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CONQUER Collaborative, an interdisciplinary effort to study brain function

Research Overview

A unique brain observatory for studying human brain function and its relationship to behavior in healthy and clinical population

Research Overview

Conquer Collaborative has a global outreach in functional optical brain imaging

Partners

Conquer Collaborative has been featured in regional and national media

Recent News & Events

Conquer Collaborative

*CoNQuER = Cognitive Neuroengineering and Quantitative Experimental Research

CollabOrative = A place where all collaborators studying brain activation and function from diverse perspectives and different purposes join arOund the circle.


Interdisciplinary


CONQUER Collaborative, an interdisciplinary effort which brings together faculty, students and resources from the School of Biomedical Engineering, Psychology, Psychiatry, Nursing and Health Professions, Neurology, Neurobiology, Neurosciences, Visualization, Gaming, Computer Science, Education and other partner units (regional, national and international).

Brain Observatory


CONQUER Collaborative aims to provide interdisciplinary researchers a unique brain observatory for studying human brain function and its relationship to behavior in healthy and clinical populations. The center is equipped with a comprehensive suite of monitoring, processing, analysis and visualization technologies to conduct human subject experiments based on two complementary modalities, namely, the near-infrared (NIR) based functional optical brain imaging [fNIR] and the electroencephalogram [EEG].

Optical Brain Imaging


The laboratory is focused on the development, systems integration and field/clinical deployment of optical brain imaging techniques to monitor human brain activity of healthy individuals and patients. The team has been at the forefront of the development of portable and wearable fNIR systems as well as in the development of signal processing methodology.

CoNQuER Gallery

Year Title Author Type

2017

Functional near-infrared spectroscopy assessment of reward perception based on visual self-expression: Coloring, doodling, and free drawing.

Abstract

Visual self-expression helps with attention and improves health and well-being. Few studies have examined reward pathway activation during different visual art tasks. This pilot study is the first to examine brain activation via functional near-infrared spectroscopy (fNIRS) during three distinct drawing tasks—coloring, doodling, and free drawing. Participants (11 men, 15 women; 8 artists, 16 non-artists) engaged in each task separated by equal intervals of rest in a block design experimental protocol. Additional data included a pre- and post survey of self-perceptions of creativity, prior experience with drawing tasks, and reflections on study participation. Overall, the three visual arts tasks resulted in significant activation of the medial prefrontal cortex compared to the rest conditions. The doodling condition resulted in maximum activation of the medial prefrontal cortex compared to coloring and free drawing; however, differences between the drawing conditions were not statistically significant. Emergent differences were seen between artists and non-artists for coloring and doodling. All three visual self-expression tasks activated the medial prefrontal cortex, indicating potential clinical applications of reward perception through art making. Participants improved in their self-perceptions of problem solving and having good ideas. Participants found the drawing tasks relaxing but wanted more time per task. Further study with varied art media and longer time on tasks are needed to determine potential interactions between participants’ backgrounds and reward activation.


Citation

Kaimal, G., Ayaz, H., Herres, J., Dieterich-Hartwell, R., Makwana, B., Kaiser, D. H., & Nasser, J. A. (2017). Functional near-infrared spectroscopy assessment of reward perception based on visual self-expression: Coloring, doodling, and free drawing. The Arts in Psychotherapy, 55, 85-92. doi:10.1016/j.aip.2017.05.004
[ link ]

Kaimal, G., Ayaz, H., Herres, J., Dieterich-Hartwell, R., Makwana, B., Kaiser, D. H., & Nasser, J. A.

Journal

2017

Neural correlates of decision making on whole body yaw rotation: an fNIRS study

Abstract

Prominent accounts of decision making state that decisions are made on the basis of an accumulation of sensory evidence, orchestrated by networks of prefrontal and parietal neural populations. Here we assess whether these findings generalize to decisions on self-motion. Participants were presented with whole body yaw rotations of different durations in a 2-Interval-Forced-Choice paradigm, and tasked to discriminate motions on the basis of their amplitude. The cortical hemodynamic response was recorded using functional near-infrared spectroscopy (fNIRS) while participants were performing the task. The imaging data was used to predict the specific response on individual experimental trials, and to predict whether the comparison stimulus would be judged larger than the reference. Classifier performance on the former variable was negligible. However, considerable performance was achieved for the latter variable, specifically using parietal imaging data. The findings provide support for the notion that activity in the parietal cortex reflects modality independent decision variables that represent the strength of the neural evidence in favor of a decision. The results are encouraging for the use of fNIRS as a method to perform neuroimaging in moving individuals.


Citation

de Winkel, K. N., Nesti, A., Ayaz, H., & Bülthoff, H. H. (2017). Neural correlates of decision making on whole body yaw rotation: an fNIRS study. Neurosci Lett. doi:10.1016/j.neulet.2017.04.053
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de Winkel, K. N., Nesti, A., Ayaz, H., & Bülthoff, H. H.

Journal

2017

Need fulfillment and the modulation of medial prefrontal activity when judging remembered past, perceived present, and imagined future identities.

Abstract

People’s abilities to integrate temporally distant identities are known to be facilitated by the fulfillment of basic psychological needs. However, the neural systems that support the integrative functions of need fulfillment are not well understood. Neuroimaging studies indicate that the medial prefrontal cortex (MPFC) differentiates remembered past, perceived present, and imagined future identities, possibly on the basis of the self-relevance attributed to specific identity representations. Using optical neuroimaging, we examined the relationship between need fulfillment and activity within the MPFC when young adults (N = 110) made trait judgments about their past, present, and future identities. Participants reporting higher need fulfillment evidenced similarly high levels of activity in the right-MPFC across the conditions; in contrast, those reporting lower need fulfillment evidenced markedly reduced activity when judging past and future identities. Results thus suggest that, among people who experience higher need fulfillment, the MPFC processes temporally distant identities in a similarly self-relevant manner. These findings provide a new type of evidence of the relationship between need fulfillment and identity integration and provide future studies with a point of entry for further examining the neural basis of identity integration.


Citation

Di Domenico, S. I., Fournier, M. A., Rodrigo, A. H., Dong, M., Ayaz, H., & Ruocco, A. C. (2017). Need fulfillment and the modulation of medial prefrontal activity when judging remembered past, perceived present, and imagined future identities. Self and Identity, 1-17. doi:10.1080/15298868.2017.1327452
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Di Domenico, S. I., Fournier, M. A., Rodrigo, A. H., Dong, M., Ayaz, H., & Ruocco, A. C.

Journal

2017

Editorial: Trends in Neuroergonomics

Abstract

This Research Topic is dedicated to Professor Raja Parasuraman who unexpectedly passed on March 22nd 2015. Raja Parasuraman's pioneering work led to the emergence of Neuroergonomics as a new scientific field. Neuroergonomics is defined as the study of the human brain in relation to performance at work and everyday settings (Parasuraman, 2003; Parasuraman and Rizzo, 2008). Since the advent of Neuroergonomics, significant progress has been made with respect to methodology and tools for the investigation of the brain and behavior at work. This is especially the case for neuroscientific methods where the availability of ambulatory hardware, wearable sensors, and advanced data analyses allow for imaging of brain dynamics in humans in applied environments.


Citation

Gramann, K., Fairclough, S. H., Zander, T. O., & Ayaz, H. (2017). Editorial: Trends in Neuroergonomics. Frontiers in Human Neuroscience, 11(165). doi:10.3389/fnhum.2017.00165
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Gramann, K., Fairclough, S. H., Zander, T. O., & Ayaz, H.

Editorial Journal Article

2017

Comparison of Brain Activation during Motor Imagery and Motor Movement Using fNIRS

Abstract

Motor-activity-related mental tasks are widely adopted for brain-computer interfaces (BCIs) as they are a natural extension of movement intention, requiring no training to evoke brain activity. The ideal BCI aims to eliminate neuromuscular movement, making motor imagery tasks, or imagined actions with no muscle movement, good candidates. This study explores cortical activation differences between motor imagery and motor execution for both upper and lower limbs using functional near-infrared spectroscopy (fNIRS). Four simple finger- or toe-tapping tasks (left hand, right hand, left foot, and right foot) were performed with both motor imagery and motor execution and compared to resting state. Significant activation was found during all four motor imagery tasks, indicating that they can be detected via fNIRS. Motor execution produced higher activation levels, a faster response, and a different spatial distribution compared to motor imagery, which should be taken into account when designing an imagery-based BCI. When comparing left versus right, upper limb tasks are the most clearly distinguishable, particularly during motor execution. Left and right lower limb activation patterns were found to be highly similar during both imagery and execution, indicating that higher resolution imaging, advanced signal processing, or improved subject training may be required to reliably distinguish them.


Citation

Batula, A. M., Mark, J. A., Kim, Y. E., & Ayaz, H. (2017). Comparison of Brain Activation during Motor Imagery and Motor Movement Using fNIRS. Computational Intelligence and Neuroscience, 2017, 12. doi:10.1155/2017/5491296
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Batula, A. M., Mark, J. A., Kim, Y. E., & Ayaz, H.

Journal

2017

Mental workload classification with concurrent electroencephalography and functional near-infrared spectroscopy

Abstract

A brain-computer interface that measures the mental workload level of operators has applications in human-computer interactions (HCI) for reducing human error and improving work efficiency. In this study, concurrently recorded electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) were combined at the decision fusion stage for the classification of three mental workload levels induced by an n-back working-memory task. An average three-class classification accuracy of 42, 43, and 49% has been achieved across 13 participants for the fNIR-alone, EEG-alone, and EEG-fNIRS combined approach, respectively. The current study demonstrated a multimodality-based approach to decode human mental workload levels that may potentially be used for adaptive HCI applications.


Citation

Liu, Y., Ayaz, H., & Shewokis, P. A. (2017). Mental workload classification with concurrent electroencephalography and functional near-infrared spectroscopy. Brain-Computer Interfaces, 1-11. doi:10.1080/2326263X.2017.1304020
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Liu, Y., Ayaz, H., & Shewokis, P. A.

Journal

2017

Spatial co-registration of functional near-infrared spectroscopy to brain MRI

Abstract


Citation

M. Chen, HM. Blumen, M. Izzetoglu, R. Holtzer, "Spatial co-registration of functional near-infrared spectroscopy to brain MRI," Journal of Neuroimaging, 2017.
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M. Chen, HM. Blumen, M. Izzetoglu, R. Holtzer

Journal

2017

Investigation of optical neuro-monitoring technique for detection of maintenance and emergence states during general anesthesia

Abstract


Citation

Hernandez-Meza, G., Izzetoglu, M., Osbakken, M., Green, M., Abubakar, H., & Izzetoglu, K. (2017). Investigation of optical neuro-monitoring technique for detection of maintenance and emergence states during general anesthesia. Journal of Clinical Monitoring and Computing, 1-17.
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Hernandez-Meza, G., Izzetoglu, M., Osbakken, M., Green, M., Abubakar, H., & Izzetoglu, K.

Journal

2017

Measuring speaker-listener neural coupling with functional near infrared spectroscopy.

Abstract


Citation

Liu, Y., E. A. Piazza, E. Simony, P. A. Shewokis, B. Onaral, U. Hasson and H. Ayaz (2017). "Measuring speaker-listener neural coupling with functional near infrared spectroscopy." Scientific Reports 7(43293).
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Liu, Y., E. A. Piazza, E. Simony, P. A. Shewokis, B. Onaral, U. Hasson and H. Ayaz

Journal

2017

Prefrontal Hemodynamics of Physical Activity and Environmental Complexity During Cognitive Work

Abstract

Objective: The aim of this study was to assess performance and cognitive states during cognitive work in the presence of physical work and in natural settings.

Background: Authors of previous studies have examined the interaction between cognitive and physical work, finding performance decrements in working memory. Neuroimaging has revealed increases and decreases in prefrontal oxygenated hemoglobin during the interaction of cognitive and physical work. The effect of environment on cognitivephysical dual tasking has not been previously considered.

Method: Thirteen participants were monitored with wireless functional near-infrared spectroscopy (fNIRS) as they performed an auditory 1-back task while sitting, walking indoors, and walking outdoors.

Results: Relative to sitting and walking indoors, auditory working memory performance declined when participants were walking outdoors. Sitting during the auditory 1-back task increased oxygenated hemoglobin and decreased deoxygenated hemoglobin in bilateral prefrontal cortex. Walking reduced the total hemoglobin available to bilateral prefrontal cortex. An increase in environmental complexity reduced oxygenated hemoglobin and increased deoxygenated hemoglobin in bilateral prefrontal cortex.

Conclusion: Wireless fNIRS is capable of monitoring cognitive states in naturalistic environments. Selective attention and physical work compete with executive processing. During executive processing loading of selective attention and physical work results in deactivation of bilateral prefrontal cortex and degraded working memory performance, indicating that physical work and concomitant selective attention may supersede executive processing in the distribution of mental resources.

Application: This research informs decision-making procedures in work where working memory, physical activity, and attention interact. Where working memory is paramount, precautions should be taken to eliminate competition from physical work and selective attention


Citation

McKendrick, R., R. Mehta, H. Ayaz, M. Scheldrup and R. Parasuraman (2017). "Prefrontal Hemodynamics of Physical Activity and Environmental Complexity During Cognitive Work." Human Factors 59(1): 147-162.
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McKendrick, R., R. Mehta, H. Ayaz, M. Scheldrup and R. Parasuraman

Journal

2017

Comparison of functional connectivity estimated from concatenated task-state data from block-design paradigm with that of continuous task.

Abstract

Functional connectivity (FC) analysis with data collected as continuous tasks and activation analysis using data from block-design paradigms are two main methods to investigate the task-induced brain activation. If the concatenated data of task blocks extracted from the block-design paradigm could provide equivalent FC information to that derived from continuous task data, it would shorten the data collection time and simplify experimental procedures, and the already collected data of block-design paradigms could be reanalyzed from the perspective of FC. Despite being used in many studies, such a hypothesis of equivalence has not yet been tested from multiple perspectives. In this study, we collected fMRI blood-oxygen-level-dependent signals from 24 healthy subjects during a continuous task session as well as in block-design task sessions. We compared concatenated task blocks and continuous task data in terms of region of interest- (ROI-) based FC, seed-based FC, and brain network topology during a short motor task. According to our results, the concatenated data was not significantly different from the continuous data in multiple aspects, indicating the potential of using concatenated data to estimate task-state FC in short motor tasks. However, even under appropriate experimental conditions, the interpretation of FC results based on concatenated data should be cautious and take the influence due to inherent information loss during concatenation into account.


Citation

Zhu, Y., L. Cheng, N. He, Y. Yang, H. Ling, H. Ayaz, S. T. J. Sun and Y. Fu (2017). "Comparison of functional connectivity estimated from concatenated task-state data from block-design paradigm with that of continuous task." Computational and Mathematical Methods in Medicine 2017(4198430): 11.
[ link ]

Zhu, Y., L. Cheng, N. He, Y. Yang, H. Ling, H. Ayaz, S. T. J. Sun and Y. Fu

Journal

2017

Acquisition, retention and transfer of simulated laparoscopic tasks using fNIR and a contextual interference paradigm

Abstract

Background

Using functional near infrared spectroscopy, a noninvasive, optical brain imaging tool that monitors changes in hemodynamics within the prefrontal cortex (PFC), we assessed performance and cognitive effort during the acquisition, retention and transfer of multiple simulated laparoscopic tasks by novice learners within a contextual interference paradigm.

Methods

Third-year medical students (n = 10) were randomized to either a blocked or random practice schedule. Across 3 days, students performed 108 acquisition trials of 3 laparoscopic tasks on the LapSim® simulator followed by delayed retention and transfer tests. Performance metrics (Global score, Total time) and hemodynamic responses (total hemoglobin (μm)) were assessed during skill acquisition, retention and transfer.

Results

All acquisition tasks resulted in significant practice schedule X trial block interactions for the left medial anterior PFC. During retention and transfer, random performed the skills in less time and had lower total hemoglobin change in the right dorsolateral PFC than blocked.

Conclusions

Compared with blocked, random practice resulted in enhanced learning through better performance and less cognitive load for retention and transfer of simulated laparoscopic tasks.


Citation

Shewokis, P. A., F. U. Shariff, Y. Liu, H. Ayaz, A. Castellanos and D. S. Lind (2017). "Acquisition, retention and transfer of simulated laparoscopic tasks using fNIR and a contextual interference paradigm." The American Journal of Surgery 213(2): 336-345.
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Shewokis, P. A., F. U. Shariff, Y. Liu, H. Ayaz, A. Castellanos and D. S. Lind

Journal

2016

Stress and gender effects on prefrontal cortex oxygenation levels assessed during single and dual-task walking conditions

Abstract


Citation

R. Holtzer, C. Scheon, E. Demetriou, J.R. Mahoney, M. Izzetoglu, C. Wang, J. Verghese, “Stress and gender effects on prefrontal cortex oxygenation levels assessed during single and dual-task walking conditions,” European Journal of Neuroscience, 2016.
[ ]

R. Holtzer, C. Scheon, E. Demetriou, J.R. Mahoney, M. Izzetoglu, C. Wang, J. Verghese

Journal

2016

Brain activation changes during locomotion in middle-aged to older adults with multiple sclerosis

Abstract


Citation

M.E.Hernandez, R. Holtzer, G. Chaparro, K. Jean, J.M. Balto, B.M. Sandroff, M. Izzetoglu, R.W. Motl, “Brain activation changes during locomotion in middle-aged to older adults with multiple sclerosis,” Journal of Neurological Sciences; 370: 277-83, 2016.
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M.E.Hernandez, R. Holtzer, G. Chaparro, K. Jean, J.M. Balto, B.M. Sandroff, M. Izzetoglu, R.W. Motl

Journal

2016

Brain activation patterns in high functioning older adults and risk of falls: prospective cohort study

Abstract


Citation

J. Verghese, C. Wang, E Ayers, M. Izzetoglu, R. Holtzer, “Brain activation patterns in high functioning older adults and risk of falls: prospective cohort study,” Neurology, 2016
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J. Verghese, C. Wang, E Ayers, M. Izzetoglu, R. Holtzer

Journal

2016

Is Functional Near Infrared Spectroscopy (fNIRS) Appropriate for your Research?

Abstract

Functional near infrared spectroscopy (fNIRS) is an emerging neuroimaging technique that has found home in various human factors and ergonomics applications. Why fNIRS? Is it better than EEG or fMRI? Is it an appropriate neuroimaging technique for my research/application? What are the methodological considerations for fNIRS analyses? This panel discussion is aimed at answering these questions, among others, when panelists from varied human factors and ergonomics applications discuss how they employ fNIRS in their investigations.


Citation

Mehta, R. K., H. Ayaz, R. McKendrick, K. Izzetoglu, B. Willems and M. Ziegler (2016). "Is Functional Near Infrared Spectroscopy (fNIRS) Appropriate for your Research?" Proceedings of the Human Factors and Ergonomics Society Annual Meeting 60(1): 188-190.
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Mehta, R. K., H. Ayaz, R. McKendrick, K. Izzetoglu, B. Willems and M. Ziegler

Conference Paper

2016

Interactions of Subjective and Objective Measures of Fatigue Defined in the Context of Brain Control of Locomotion

Abstract


Citation

R. Holtzer, J Yuan, J. Verghese, J.R. Mahoney, M. Izzetoglu, C. Wang, “Interactions of Subjective and Objective Measures of Fatigue Defined in the Context of Brain Control of Locomotion”, J Gerontol A Biol Sci Med Sci, 1–7, 2016
[ ]

R. Holtzer, J Yuan, J. Verghese, J.R. Mahoney, M. Izzetoglu, C. Wang

Journal

2016

The relationship between dorsolateral prefrontal activation and speech performance-based social anxiety using functional near infrared spectroscopy

Abstract


Citation

L.H. Glassman, A.T. Kuster, J.A. Shaw, E.M. Forman, M. Izzetoglu, A. Matteucci, J.D. Herbert, “The relationship between dorsolateral prefrontal activation and speech performance-based social anxiety using functional near infrared spectroscopy,” Brain Imaging and Behavior, 1-11, 2016.
[ ]

L.H. Glassman, A.T. Kuster, J.A. Shaw, E.M. Forman, M. Izzetoglu, A. Matteucci, J.D. Herbert

Journal

2016

The role of prefrontal cortex during postural control in Parkinsonian syndromes a functional near-infrared spectroscopy study

Abstract


Citation

J.R. Mahoney, R. Holtzer, M. Izzetoglu, V. Zemon, J. Verghese, G. Allali, “The role of prefrontal cortex during postural control in Parkinsonian syndromes a functional near-infrared spectroscopy study,” Brain research, 633:126-38, 2016.
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J.R. Mahoney, R. Holtzer, M. Izzetoglu, V. Zemon, J. Verghese, G. Allali

Journal

2016

The effects of a brief acceptance-based behavioral treatment vs. traditional cognitive-behavioral treatment for public speaking anxiety: Differential effects on performance and neurophysiology

Abstract


Citation

L.H. Glassman, E.M. Forman, J.D. Herbert, L.E. Bradley, E.E. Foster, M. Izzetoglu, A.C. Ruocco, “The effects of a brief acceptance-based behavioral treatment vs. traditional cognitive-behavioral treatment for public speaking anxiety: Differential effects on performance and neurophysiology,” Behavior Modification, 11:0145445516629939, 2016.
[ ]

L.H. Glassman, E.M. Forman, J.D. Herbert, L.E. Bradley, E.E. Foster, M. Izzetoglu, A.C. Ruocco

Journal

2016

Does a combination of virtual reality, neuromodulation and neuroimaging provide a comprehensive platform for neurorehabilitation? – A narrative review of the literature.

Abstract

In the last decade, virtual reality (VR) training has been used extensively in video games and military training to provide a sense of realism and environmental interaction to its users. More recently, VR training has been explored as a possible adjunct therapy for people with motor and mental health dysfunctions. The concept underlying VR therapy as a treatment for motor and cognitive dysfunction is to improve neuroplasticity of the brain by engaging users in multisensory training. In this review, we discuss the theoretical framework underlying the use of VR as a therapeutic intervention for neurorehabilitation and provide evidence for its use in treating motor and mental disorders such as cerebral palsy, Parkinson’s disease, stroke, schizophrenia, anxiety disorders, and other related clinical areas. While this review provides some insights into the efficacy of VR in clinical rehabilitation and its complimentary use with neuroimaging (e.g., fNIRS and EEG) and neuromodulation (e.g., tDCS and rTMS), more research is needed to understand how different clinical conditions are affected by VR therapies (e.g., stimulus presentation, interactivity, control and types of VR). Future studies should consider large, longitudinal randomized controlled trials to determine the true potential of VR therapies in various clinical populations.


Citation

Teo, W. P., Muthalib, M., Yamin, S., Hendy, A. M., Bramstedt, K., Kotsopoulos, E., . . . Ayaz, H. (2016). Does a combination of virtual reality, neuromodulation and neuroimaging provide a comprehensive platform for neurorehabilitation? – A narrative review of the literature. Frontiers in Human Neuroscience, 10:284. doi:10.3389/fnhum.2016.00284
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Teo, W. P., Muthalib, M., Yamin, S., Hendy, A. M., Bramstedt, K., Kotsopoulos, E., Perrey, S., Ayaz, H.

Journal

2016

Modulation of Functional Connectivity and Activation during Preparation for Hand Movement.

Abstract

Traditional and new generations of neuroimaging techniques allow observing the modulation of brain activities during transition periods between rest and physical movement execution. A thorough understanding of the brain activity and functional connectivity changes during these transitions could contribute to increasing the precision and decreasing the latency of anticipation-based brain–computer interfaces, and improving human-system integration in general. Consistent with the neuroergonomic approach, functional near-infrared spectroscopy can monitor the outer cortex during extensive physical movement and in realistic settings using wearable and portable sensors. Methods: In this study, 19 healthy subjects were monitored with functional near-infrared spectroscopy during rest, a fist opening and closing task, and the transition period preceding the task. Functional connectivity analysis was used to evaluate how the transition period preceding the task modulated the brain activities. Results: There were several increases in functional connectivity during the transition period, especially between the right dorsolateral prefrontal cortex and the contralateral primary somatosensory and primary motor cortices, as well as the functional connectivity connecting the contralateral primary somatosensory cortex with the ipsilateral primary somatosensory cortex and the primary motor cortex. Regions located in the sensorimotor networks and right dorsolateral prefrontal cortex were also found to be activated during the transition period. Conclusions: These results demonstrate that the sensorimotor network is interacting with the high-level cognitive brain network during the transition period to maintain the preparation state. Furthermore, functional near-infrared spectroscopy is an emerging tool well-suited for region specific task-related and resting-state functional connectivity analysis. The results and the approach presented here suggest that operators' intention to move can be detected before the actual movement, and that could be employed for development of more intuitive and natural interfaces between human and machine systems.


Citation

Cheng, L., Ayaz, H., Sun, J., Tong, S., & Onaral, B. (2016). Modulation of Functional Connectivity and Activation during Preparation for Hand Movement. IIE Transactions on Occupational Ergonomics and Human Factors, 4(2-3), 175-187. doi:10.1080/21577323.2016.1191560
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Cheng, L., Ayaz, H., Sun, J., Tong, S., & Onaral, B

Journal

2016

Basic psychological needs and neurophysiological responsiveness to decisional conflict: an event-related potential study of integrative self-processes

Abstract

Fulfillment of the basic psychological needs for competence, relatedness, and autonomy is believed to facilitate people’s integrative tendencies to process psychological conflicts and develop a coherent sense of self. The present study therefore used event-related potentials (ERPs) to examine the relation between need fulfillment and the amplitude of conflict negativity (CN), a neurophysiological measure of conflict during personal decision making. Participants completed a decision-making task in which they made a series of forced choices according to their personal preferences. Three types of decision-making situations were created on the basis of participants’ unique preference ratings, which were obtained prior to ERP recording: low-conflict situations (choosing between an attractive and an unattractive option), high-conflict approach-approach situations (choosing between two similarly attractive options), and high-conflict avoidance-avoidance situations (choosing between two similarly unattractive options). As expected, CN amplitudes were larger in high- relative to low-conflict situations, and source localization analyses suggested that the anterior cingulate cortex was the generating structure of the CN. Most importantly, people reporting higher need fulfillment exhibited larger CN amplitudes in avoidance–avoidance situations relative to low-conflict situations; to a lesser extent, they also exhibited larger CN amplitudes in approach–approach situations relative to low-conflict situations. By contrast, people reporting lower need fulfillment exhibited CN amplitudes that poorly discriminated the three decision situations. These results suggest that need fulfillment may promote self-coherent functioning by increasing people’s receptivity to and processing of events that challenge their abilities to make efficient, self-congruent choices.


Citation

Di Domenico, S. I., Le, A., Liu, Y., Ayaz, H., & Fournier, M. A. (2016). Basic psychological needs and neurophysiological responsiveness to decisional conflict: an event-related potential study of integrative self-processes. Cognitive, Affective, & Behavioral Neuroscience, 1-18. doi:10.3758/s13415-016-0436-1
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Di Domenico, S. I., Le, A., Liu, Y., Ayaz, H., & Fournier, M. A.

Journal

2016

Decision Support and Shared Decision Making About Active Surveillance Versus Active Treatment Among Men Diagnosed with Low-Risk Prostate Cancer: a Pilot Study

Abstract

This study aimed to explore the effects of a decision support intervention (DSI) and shared decision making (SDM) on knowledge, perceptions about treatment, and treatment choice among men diagnosed with localized low-risk prostate cancer (PCa). At a multidisciplinary clinic visit, 30 consenting men with localized low-risk PCa completed a baseline survey, had a nurse-mediated online DS session to clarify preference for active surveillance (AS) or active treatment (AT), and met with clinicians for SDM. Participants also completed a follow-up survey at 30 days. We assessed change in treatment knowledge, decisional conflict, and perceptions and identified predictors of AS. At follow-up, participants exhibited increased knowledge (p < 0.001), decreased decisional conflict (p < 0.001), and more favorable perceptions of AS (p = 0.001). Furthermore, 25 of the 30 participants (83 %) initiated AS. Increased family and clinician support predicted this choice (p < 0.001). DSI/SDM prepared patients to make an informed decision. Perceived support of the decision facilitated patient choice of AS.


Citation

Myers, R. E., Leader, A. E., Censits, J. H., Trabulsi, E. J., Keith, S. W., Petrich, A. M., . . . Gomella, L. G. (2016). Decision Support and Shared Decision Making About Active Surveillance Versus Active Treatment Among Men Diagnosed with Low-Risk Prostate Cancer: a Pilot Study. Journal of Cancer Education, 1-6. doi:10.1007/s13187-016-1073-7
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Myers, R. E., Leader, A. E., Censits, J. H., Trabulsi, E. J., Keith, S. W., Petrich, A. M., Quinn, A. M., Den, R. B., Hurwitz, M. D., Lallas, C. D., Hegarty, S. E., Dicker, A. P., Zeigler-Johnson, C. M., Giri, V. N., Ayaz, H., Gomella, L. G.

Journal

2016

Evidence of anhedonia and differential reward processing in prefrontal cortex among post-withdrawal patients with prescription opiate dependence

Abstract

Anhedonia is an important but understudied element of a neuroadaptive model underlying vulnerability to relapse in opioid dependence. Previous research using fMRI has shown reduced activation to pleasant stimuli in rostral prefrontal cortex among heroin-dependent patients in early recovery. This study evaluated the presence of anhedonia among recently withdrawn prescription opiate dependent patients (PODP) in residential treatment compared to control subjects. Anhedonia was assessed using self-report, affect-modulated startle response (AMSR), and a cue reactivity task during which participant’s rostral prefrontal cortex (RPFC) and ventrolateral prefrontal cortex (VLPFC) was monitored with functional near infrared spectroscopy (fNIRS). The cue reactivity task included three distinct categories of natural reward stimuli: highly palatable food, positive social situations, and intimate (non-erotic) interactions. PODP reported greater anhedonia on self-report (Snaith–Hamilton Pleasure Scale), and showed reduced hedonic response to positive stimuli in the AMSR task relative to controls. PODP also exhibited reduced neural activation in bilateral RPFC and left VLPFC in response to food images and reduced left VLPFC in response to images depicting positive social situations relative to controls. No differences were found for emotionally intimate stimuli. When patients were divided into groups based on the Snaith–Hamilton criteria for the presence or absence of anhedonia, patients endorsing anhedonia showed reduced neural responses to images depicting positive social stimuli and food relative to patients who did not endorse anhedonia. Activations were in areas of RPFC that support the retrieval of episodic memories. The results suggest the presence of anhedonia in a subsample of PODP.


Citation

Huhn, A. S., Meyer, R. E., Harris, J. D., Ayaz, H., Deneke, E., Stankoski, D. M., & Bunce, S. C. (2016). Evidence of anhedonia and differential reward processing in prefrontal cortex among post-withdrawal patients with prescription opiate dependence. Brain Research Bulletin, 123, 102-109. doi:http://dx.doi.org/10.1016/j.brainresbull.2015.12.004
[ link ]

Huhn, A. S., Meyer, R. E., Harris, J. D., Ayaz, H., Deneke, E., Stankoski, D. M., & Bunce, S. C.

Journal

2016

Into The Wild: Neuroergonomic Differentiation of Hand-Held and Augmented Reality Wearable Displays During Outdoor Navigation with Functional Near Infrared Spectroscopy

Abstract

Highly mobile computing devices promise to improve quality of life, productivity, and performance. Increased situation awareness and reduced mental workload are two potential means by which this can be accomplished. However, it is difficult to measure these concepts in the ‘wild’. We employed an ultra-portable battery operated and wireless functional near infrared spectroscopy (fNIRS) to non-invasively measure hemodynamic changes in the brain’s prefrontal cortex. Measurements were taken during navigation of a college campus with either a hand-held display, or an augmented reality wearable display. Hemodynamic measures were also paired with secondary tasks of visual perception and auditory working memory to provide behavioral assessment of situation awareness and mental workload. Navigating with an augmented reality wearable display produced the least workload during both secondary tasks. The hemodynamics associated with errors were also different between the two devices. Errors with an augmented reality wearable display were associated with increased prefrontal activity and the opposite was observed for the hand-held display. This suggests that the cognitive mechanisms underlying errors between the two devices differ. These findings show fNIRS is a valuable tool for assessing new technology in ecologically valid settings and that head-mounted displays offer benefits with regards to mental workload while navigating, and potentially superior situation awareness with improved display design.


Citation

Mckendrick R, Parasuraman R, Murtza R, Formwalt A, Baccus W, Paczynski M and Ayaz H (2016). Into The Wild: Neuroergonomic Differentiation of Hand-Held and Augmented Reality Wearable Displays During Outdoor Navigation with Functional Near Infrared Spectroscopy. Front. Hum. Neurosci. 10:216. doi: 10.3389/fnhum.2016.00216
[ link ]

Mckendrick R, Parasuraman R, Murtza R, Formwalt A, Baccus W, Paczynski M and Ayaz H

Journal

2016

Predicting Treatment Outcomes from Prefrontal Cortex Activation for Self-Harming Patients with Borderline Personality Disorder: A Preliminary Study

Abstract

Self-harm is a potentially lethal symptom of borderline personality disorder (BPD) that often improves with dialectical behavior therapy (DBT). While DBT is effective for reducing self-harm in many patients with BPD, a small but significant number of patients either does not improve in treatment or ends treatment prematurely. Accordingly, it is crucial to identify factors that may prospectively predict which patients are most likely to benefit from and remain in treatment. In the present preliminary study, twenty-nine actively self-harming patients with BPD completed brain-imaging procedures probing activation of the prefrontal cortex during impulse control prior to beginning DBT and after seven months of treatment. Patients that reduced their frequency of self-harm the most over treatment displayed lower levels of neural activation in the bilateral dorsolateral prefrontal cortex prior to beginning treatment, and they showed the greatest increases in activity within this region after seven months of treatment. Prior to starting DBT, treatment non-completers demonstrated greater activation than treatment-completers in the medial prefrontal cortex and right inferior frontal gyrus. Reductions in self-harm over the treatment period were associated with increases in activity in right dorsolateral prefrontal cortex even after accounting for improvements in depression, mania, and BPD symptom severity. These findings suggest that pre-treatment patterns of activation in the prefrontal cortex underlying impulse control may be prospectively associated with improvements in self-harm and treatment attrition for patients with BPD treated with DBT.


Citation

Ruocco AC, Rodrigo AH, McMain SF, Page-Gould E, Ayaz H and Links PS (2016). Predicting Treatment Outcomes from Prefrontal Cortex Activation for Self-Harming Patients with Borderline Personality Disorder: A Preliminary Study. Front. Hum. Neurosci. 10:220. doi: 10.3389/fnhum.2016.00220
[ link ]

Ruocco AC, Rodrigo AH, McMain SF, Page-Gould E, Ayaz H and Links PS

Journal

2016

Developing an Optical Brain-Computer Interface for Humanoid Robot Control

Abstract

This work evaluates the feasibility of a motor imagery-based optical brain-computer interface (BCI) for humanoid robot control. The functional near-infrared spectroscopy (fNIRS) based BCI-robot system developed in this study operates through a high-level control mechanism where user specifies a target action through the BCI and the robot performs the set of micro operations necessary to fulfill the identified goal. For the evaluation of the system, four motor imagery tasks (left hand, right hand, left foot, and right foot) were mapped to operational commands (turn left, turn right, walk forward, walk backward) that were sent to the robot in real time to direct the robot navigating a small room. An ecologically valid offline analysis with minimal preprocessing shows that seven subjects could achieve an average accuracy of 32.5 %. This was increased to 43.6 % just by including calibration data from the same day of the robot control using the same cap setup, indicating that day-of calibration following the initial training may be important for BCI control.


Citation

Batula, A. M., Mark, J., Kim, Y. E., & Ayaz, H. (2016). Developing an Optical Brain-Computer Interface for Humanoid Robot Control. In D. D. Schmorrow & C. M. Fidopiastis (Eds.), Foundations of Augmented Cognition: Neuroergonomics and Operational Neuroscience (Vol. Part I, LNAI 9743, pp. 1-11).
[ link ]

Batula, A. M., Mark, J., Kim, Y. E., & Ayaz, H.

Book Chapter

2016

Evaluating Neural Correlates of Constant-Therapy Neurorehabilitation Task Battery: An fNIRS Pilot Study

Abstract

The development of cognitive task battery applications for rehabilitation in telemedicine is a rapidly evolving field, with several tablet or web based programs already helping those suffering from working memory dysfunction or attention deficit disorders. However, there is little physiological evidence supporting a measurably significant change in brain function from using these programs. The present study sought to provide an initial assessment using the portable and wearable neuroimaging modality of functional near-infrared spectroscopy (fNIRS) that can be used in ambulatory and home settings and has the potential to add value in the assessment of clinical patients’ recovery throughout their therapy.


Citation

Mark, J., Onaral, B., & Ayaz, H. (2016). Evaluating Neural Correlates of Constant-Therapy Neurorehabilitation Task Battery: An fNIRS Pilot Study. In D. D. Schmorrow & C. M. Fidopiastis (Eds.), Foundations of Augmented Cognition: Neuroergonomics and Operational Neuroscience (Vol. Part I, LNAI 9743, pp. 1-11).
[ link ]

Mark, J., Onaral, B., Ayaz, H.

Book Chapter

2016

Examining the Neural Correlates of Incidental Facial Emotion Encoding Within the Prefrontal Cortex Using Functional Near-Infrared Spectroscopy

Abstract

Previous neuroimaging research has implicated the prefrontal cortex (PFC) as a region of the brain that is vital for various aspects of emotion processing. The present study sought to examine the neural correlates of incidental facial emotion encoding, with regard to neutral and fearful faces, within the PFC. Thirty-nine healthy adults were presented briefly with neutral and fearful faces and the evoked hemodynamic oxygenation within the PFC was measured using 16-channel continuous-wave functional near-infrared spectroscopy. When viewing fearful as compared to neutral faces, participants demonstrated higher levels of activation within the right medial PFC. On the other hand, participants demonstrated lower levels of activation within the left medial PFC and left lateral PFC when viewing fearful faces, as compared to neutral faces.These findings are consistent with previous fMRI research, and suggest that fearful faces are linked to a neural response within the right medial PFC, whereas neutral faces appear to elicit a neural response within left medial and lateral areas of the PFC.


Citation

Rodrigo, A. H., Ayaz, H., & Ruocco, A. C. (2016). Examining the Neural Correlates of Incidental Facial Emotion Encoding within the Prefrontal Cortex Using Functional Near-Infrared Spectroscopy. In D. D. Schmorrow & C. M. Fidopiastis (Eds.), Foundations of Augmented Cognition: Neuroergonomics and Operational Neuroscience (Vol. Part I, LNAI 9743, pp. 1-11).
[ link ]

Rodrigo, A., Ayaz, H., Ruocco, A.

Book Chapter

2016

Monitoring Driver Cognitive Load using Near Infrared Spectroscopy in Partially Autonomous Cars

Abstract


Citation

Sibi, S., Ayaz, H., Kuhns, D. P., Sirkin, D. M., Ju, W. (2016) Monitoring Driver Cognitive Load using Near Infrared Spectroscopy in Partially Autonomous Cars, IEEE Intelligent Vehicles Symposium (IV'16), June 19-22, 2016, Gothenburg, Sweden.
[ ]

Sibi, S., Ayaz, H., Kuhns, D. P., Sirkin, D. M., Ju, W.

Conference Paper

2016

enAble Games: Designing active video games to promote fitness and physical activity in youth with cerebral palsy

Abstract


Citation

O’Neil, M. E., Shewokis, P. A., Ayaz H. , Gray, R, Diefenbach, P. J. (2016) enAble Games: Designing active video games to promote fitness and physical activity in youth with cerebral palsy, International Conference on Cerebral Palsy and other Childhood-onset Disabilities, June 1-4, 2016, Stockholm, Sweden
[ ]

O’Neil, M. E., Shewokis, P. A., Ayaz H. , Gray, R, Diefenbach, P. J.

Conference Paper

2016

Acquisition of Simulated Surgical Tasks Using fNIR and a Contextual Interference Paradigm

Abstract


Citation

Shewokis, P. A., Shariff, F. U., Syed, M., Ayaz, H., Castellanos, A., Lind, D. S. (2016) Acquisition of Simulated Surgical Tasks Using fNIR and a Contextual Interference Paradigm, Association for Surgical Education (ASE'16), April 12-16, 2016, Boston, MA
[ ]

Shewokis, P. A., Shariff, F. U., Syed, M., Ayaz, H., Castellanos, A., Lind, D. S.

Conference Paper

2016

Changes in neural activity of the prefrontal cortex during eating in humans

Abstract


Citation

Nasser, J.A., Ayaz, H., Golen, R.P., Makwana, B., Albajri, E., Price, M. B., Mogil, S., Cucalon, G., DelParigi, A. (2016) Changes in neural activity of the prefrontal cortex during eating in humans, British Feeding and Drinking Group, April 7-8, 2016, Teddington, London
[ ]

Nasser, J.A., Ayaz, H., Golen, R.P., Makwana, B., Albajri, E., Price, M. B., Mogil, S., Cucalon, G., DelParigi, A.

Conference Paper

2016

Cognitive Load Assessment of Simulated Laparoscopic Surgical Tasks Using Optical Imaging

Abstract


Citation

Shariff, F. U., Syed, M., Renza-Stingone, E., Ayaz, H., Castellanos, A., Lind, D. S., Shewokis, P. A. (2016) Cognitive Load Assessment of Simulated Laparoscopic Surgical Tasks Using Optical Imaging, Surg Endosc 30:S211–S263
[ ]

Shariff, F. U., Syed, M., Renza-Stingone, E., Ayaz, H., Castellanos, A., Lind, D. S., Shewokis, P. A.

Journal

2016

Linking Trait-Based Phenotypes to Prefrontal Cortex Activation during Inhibitory Control

Abstract

Inhibitory control is subserved in part by discrete regions of the prefrontal cortex whose functionality may be altered according to specific trait-based phenotypes. Using a unified model of normal range personality traits, we examined activation within lateral and medial aspects of the prefrontal cortex during a manual go/no-go task. Evoked hemodynamic oxygenation within the prefrontal cortex was measured in 106 adults using a 16-channel continuous-wave functional near-infrared spectroscopy system. Within lateral regions of the prefrontal cortex, greater activation was associated with higher trait levels of extraversion, agreeableness and conscientiousness, and lower neuroticism. Higher agreeableness was also related to more activation in the medial prefrontal cortex during inhibitory control. These results suggest that personality traits reflecting greater emotional stability, extraversion, agreeableness and conscientiousness may be associated with more efficient recruitment of control processes subserved by lateral regions of the prefrontal cortex. These findings highlight key links between trait-based phenotypes and neural activation patterns in the prefrontal cortex underlying inhibitory control.


Citation

Rodrigo, A. H., Di Domenico, S. I., Graves, B., Lam, J., Ayaz, H., Bagby, R. M., & Ruocco, A. C. (2016). Linking Trait-Based Phenotypes to Prefrontal Cortex Activation during Inhibitory Control. Social Cognitive and Affective Neuroscience. 11 (1), pp55-65 doi: 10.1093/scan/nsv091
[ link ]

Rodrigo, A. H., Di Domenico, S. I., Graves, B., Lam, J., Ayaz, H., Bagby, R. M., & Ruocco, A. C.

Journal

2015

Neurological Gait Abnormalities Moderate the Functional Brain Signature of the Posture First Hypothesis

Abstract


Citation

R. Holtzer, J.R. Mahoney, M. Izzetoglu, C. Wang, S. England, J. Verghese, “Neurological Gait Abnormalities Moderate the Functional Brain Signature of the Posture First Hypothesis”, Brain Topography, 1-10, 2015.
[ ]

R. Holtzer, J.R. Mahoney, M. Izzetoglu, C. Wang, S. England, J. Verghese

Journal

2015

Online Fronto-cortical Control Of Simple and Attention-Demanding Locomotion in Humans

Abstract


Citation

R. Holtzer, J.R. Mahoney, M. Izzetoglu, C. Wang, S. England, J. Verghese, “Online Fronto-cortical Control Of Simple and Attention-Demanding Locomotion in Humans”, Neuroimage, 112:152-159, 2015
[ ]

R. Holtzer, J.R. Mahoney, M. Izzetoglu, C. Wang, S. England, J. Verghese

Journal

2015

Near-Infrared Spectroscopy for the Evaluation of Anesthetic Depth

Abstract


Citation

G. Hernandez-Meza, M. Izzetoglu, M. Osbakken, M. Green, K. Izzetoglu, “Near-Infrared Spectroscopy for the Evaluation of Anesthetic Depth,” BioMed Research International, vol. 11, 2015.
[ ]

G. Hernandez-Meza, M. Izzetoglu, M. Osbakken, M. Green, K. Izzetoglu

Journal

2015

Detection of Impaired Cerebral Autoregulation Following Hypoxia Ischemia in Newborn Piglets Using a Novel Near Infrared Spectroscopy Technique

Abstract


Citation

Malaeb S., Izzetoglu M., Du J., McGowan J. "Detection of Impaired Cerebral Autoregulation Following Hypoxia Ischemia in Newborn Piglets Using a Novel Near Infrared Spectroscopy Technique," PAS 2015 Annual Meeting
[ ]

Malaeb S., Izzetoglu M., Du J., McGowan J.

Conference Paper

2015

Non-invasive Monitoring of Cerebral Edema in Real-Time Following Hypoxia Ischemia in Newborn Piglets Using Near Infrared Spectroscopy

Abstract


Citation

Malaeb S., Izzetoglu M., Du J., McGowan J. "Non-invasive Monitoring of Cerebral Edema in Real-Time Following Hypoxia Ischemia in Newborn Piglets Using Near Infrared Spectroscopy," PAS 2015 Annual Meeting
[ ]

Malaeb S., Izzetoglu M., Du J., McGowan J.

Conference Paper

2015

Investigation of hemodynamic changes during general anesthesia via functional near infrared spectroscopy

Abstract


Citation

Green MS, Hernandez G, Izzetoglu K, Osbakken M, Rao S, Izzetoglu M. Investigation of hemodynamic changes during general anesthesia via functional near infrared spectroscopy. American Society of Anesthesiology National Meeting, San Diego, CA. 2015.
[ ]

Green MS, Hernandez G, Izzetoglu K, Osbakken M, Rao S, Izzetoglu M.

Conference Paper

2015

Neural Correlates of Affective Context in Facial Expression Analysis: A Simultaneous EEG-fNIRS Study

Abstract

We present a framework to measure the correlation between spontaneous human facial affective expressions and relevant brain activity. The affective states were registered from the video capture of facial expression and related neural activity was measured using wearable and portable neuroimaging systems: functional near infrared spectroscopy (fNIRS), electroencephalography (EEG) to asses both hemodynamic and electrophysiological responses. The methodology involves the simultaneous detection and comparison of various affective expressions by multi-modalities and classification of spatiotemporal data with neural signature traits. The experimental results show strong correlation between the spontaneous facial affective expressions and the affective states related brain activity. We propose a multimodal approach to jointly evaluate fNIRS signals and EEG signals for affective state detection. Results indicate that proposed method with fNIRS+EEG improves performance over fNIRS or EEG only approaches. These findings encourage further studies of the joint utilization of video and brain signals for face perception and braincomputer interface (BCI) applications.


Citation

Sun, Y., Ayaz, H., Akansu, A. (2015). Neural Correlates of Affective Context in Facial Expression Analysis: A Simultaneous EEG-fNIRS Study, IEEE Global SIP, Orlando, FL
[ link ]

Sun, Y., Ayaz, H., Akansu, A.

Conference Paper

2015

An Optical Brain Imaging Study on the Improvements in Mathematical Fluency from Game-based Learning

Abstract

In this study we examined the effectiveness of game-based learning in improving math fluency compared to a conventional drill and practice approach. An optical brain imaging method called functional near-infrared spectroscopy (fNIR) was utilized to assess changes in brain activation in prefrontal cortex related to cognitive load and working memory functions, so that the improvement gained by the increased attentional and cognitive training involved in a mobile game called MathDash could be examined in terms of how and why game-based learning can be effective. Overall, our experiment with college students indicated that Math Dash was equally effective in terms of improving computational fluency in comparison to the drill and practice approach.


Citation

Çakır, M. P., Çakır, N. A., Ayaz, H., & Lee, F. J. (2015). An Optical Brain Imaging Study on the Improvements in Mathematical Fluency from Game-based Learning. ACM CHIPLAY, London, UK pp209-219 doi: 10.1145/2793107.2793133
[ link ]

Çakır, M. P., Çakır, N. A., Ayaz, H., & Lee, F. J.

Conference Paper

2015

Neural Adaptation to a Working Memory Task: A Concurrent EEG-fNIRS Study

Abstract

Simultaneously recorded electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) measures from sixteen subjects were used to assess neural correlates of a letter based n-back working memory task. We found that EEG alpha power increased and prefrontal cortical oxygenation decreased with increased practice time for the high memory load condition (2-back), suggesting lower brain activation and a tendency toward the ‘idle’ state. The cortical oxygenation changes for the low memory load conditions (0-back and 1-back) changed very little throughout the training session which the behavioral scores showed high accuracy and a ceiling effect. No significant effect of practice time were found for theta power or the behavioral performance measures.


Citation

Liu, Y., Ayaz, H., Onaral, B., & Shewokis, P. (2015). Neural Adaptation to a Working Memory Task: A Concurrent EEG-fNIRS Study. In D. D. Schmorrow & C. M. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 9183, pp. 268-280): Springer International Publishing.
[ link ]

Liu, Y., Ayaz, H., Onaral, B., & Shewokis, P.

Book Chapter

2015

Investigation of Functional Near Infrared Spectroscopy in Evaluation of Pilot Expertise Acquisition

Abstract

Functional Near-Infrared (fNIR) spectroscopy is an optical brain imaging technology that enables assessment of brain activity through the intact skull in human subjects. fNIR systems developed during the last decade allow for a rapid, non-invasive method of measuring the brain activity of a subject while conducting tasks in realistic environments. This paper examines the hemodynamic changes associated with expertise development during C-130j simulated flying missions.


Citation

Hernandez-Meza, G., Slason, L., Ayaz, H., Craven, P., Oden, K., & Izzetoglu, K. (2015). Investigation of Functional Near Infrared Spectroscopy in Evaluation of Pilot Expertise Acquisition. In D. D. Schmorrow & C. M. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 9183, pp. 232-243): Springer International Publishing.
[ link ]

Hernandez-Meza, G., Slason, L., Ayaz, H., Craven, P., Oden, K., & Izzetoglu, K.

Book Chapter

2015

Brain-in-the-Loop Learning Using fNIR and Simulated Virtual Reality Surgical Tasks: Hemodynamic and Behavioral Effects

Abstract

Functional near infrared spectroscopy (fNIR) is a noninvasive, portable optical imaging tool to monitor changes in hemodynamic responses (i.e., oxygenated hemoglobin (HbO)) within the prefrontal cortex (PFC) in response to sensory, motor or cognitive activation. We used fNIR for monitoring PFC activation during learning of simulated laparoscopic surgical tasks throughout 4 days of training and testing. Blocked (BLK) and random (RND) practice orders were used to test the practice schedule effect on behavioral, hemodynamic responses and relative neural efficiency (EFFrel-neural) measures during transfer. Left and right PFC for both tasks showed significant differences with RND using less HbO than BLK. Cognitive workload showed RND exhibiting high EFFrel-neural across the PFC for the coordination task while the more difficult cholecystectomy task showed EFFrel-neural differences only in the left PFC. Use of brain activation, behavioral and EFFrel-neural measures can provide a more accurate depiction of the generalization or transfer of learning.


Citation

Shewokis, P., Ayaz, H., Panait, L., Liu, Y., Syed, M., Greenawald, L., Shariff, F., Castellanos, A., Scott Lind, D. (2015). Brain-in-the-Loop Learning Using fNIR and Simulated Virtual Reality Surgical Tasks: Hemodynamic and Behavioral Effects. In D. D. Schmorrow & C. M. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 9183, pp. 324-335): Springer International Publishing.
[ link ]

Shewokis, P., Ayaz, H., Panait, L., Liu, Y., Syed, M., Greenawald, L., Shariff, F., Castellanos, A., Scott Lind, D.

Book Chapter

2015

Wearable functional Near Infrared Spectroscopy (fNIRS) and transcranial Direct Current Stimulation (tDCS): Expanding Vistas for Neurocognitive Augmentation

Abstract

Contemporary studies with transcranial direct current stimulation (tDCS) provide a growing base of evidence for enhancing cognition through the non-invasive delivery of weak electric currents to the brain. The main effect of tDCS is to modulate cortical excitability depending on the polarity of the applied current. However, the underlying mechanism of neuromodulation is not well understood. A new generation of functional near infrared spectroscopy (fNIRS) systems is described that are miniaturized, portable, and include wearable sensors. These developments provide an opportunity to couple fNIRS with tDCS, consistent with a neuroergonomics approach for joint neuroimaging and neurostimulation investigations of cognition in complex tasks and in naturalistic conditions. The effects of tDCS on complex task performance and the use of fNIRS for monitoring cognitive workload during task performance are described. Also explained is how fNIRS + tDCS can be used simultaneously for assessing spatial working memory. Mobile optical brain imaging is a promising neuroimaging tool that has the potential to complement tDCS for realistic applications in natural settings.


Citation

Mckendrick R, Parasuraman R and Ayaz H(2015) Wearable functional Near Infrared Spectroscopy (fNIRS) and transcranial Direct Current Stimulation (tDCS): Expanding Vistas for Neurocognitive Augmentation. Front. Syst. Neurosci. 9:27. doi:10.3389/fnsys.2015.00027
[ link ]

Ryan McKendrick, Raja Parasuraman, and Hasan Ayaz

Journal

2015

Decision-making conflict and the neural efficiency hypothesis of intelligence: A functional near-infrared spectroscopy investigation

Abstract

Research on the neural efficiency hypothesis of intelligence (NEH) has revealed that the brains of more intelligent individuals consume less energy when performing easy cognitive tasks but more energy when engaged in difficult mental operations. However, previous studies testing the NEH have relied on cognitive tasks that closely resemble psychometric tests of intelligence, potentially confounding efficiency during intelligence-test performance with neural efficiency per se. The present study sought to provide a novel test of the NEH by examining patterns of prefrontal activity while participants completed an experimental paradigm that is qualitatively distinct from the contents of psychometric tests of intelligence. Specifically, participants completed a personal decision-making task (e.g., which occupation would you prefer, dancer or chemist?) in which they made a series of forced choices according to their subjective preferences. The degree of decisional conflict (i.e., choice difficulty) between the available response options was manipulated on the basis of participants' unique preference ratings for the target stimuli, which were obtained prior to scanning. Evoked oxygenation of the prefrontal cortex was measured using 16-channel continuous-wave functional near-infrared spectroscopy. Consistent with the NEH, intelligence predicted decreased activation of the right inferior frontal gyrus (IFG) during low-conflict situations and increased activation of the right-IFG during high-conflict situations. This pattern of right-IFG activity among more intelligent individuals was complemented by faster reaction times in high-conflict situations. These results provide new support for the NEH and suggest that the neural efficiency of more intelligent individuals generalizes to the performance of cognitive tasks that are distinct from intelligence tests.


Citation

Stefano I. Di Domenico, Achala H. Rodrigo, Hasan Ayaz, Marc A. Fournier, Anthony C. Ruocco, Decision-making conflict and the neural efficiency hypothesis of intelligence: A functional near-infrared spectroscopy investigation, NeuroImage, Volume 109, 1 April 2015, Pages 307-317, ISSN 1053-8119, http://dx.doi.org/10.1016/j.neuroimage.2015.01.039. (http://www.sciencedirect.com/science/article/pii/S1053811915000555)
[ link ]

Stefano I. Di Domenico, Achala H. Rodrigo, Hasan Ayaz, Marc A. Fournier, Anthony C. Ruocco

Journal

2014

Brain Response to Reading Tasks and Reading raining in Dyslexia as Measured by fNIRS

Abstract


Citation

Chuntonov O., Izzetoglu M., Sela I., Onaral B. “Brain Response to Reading Tasks and Reading raining in Dyslexia as Measured by fNIRS,” fNIRS Conference, 2014.
[ ]

Chuntonov O., Izzetoglu M., Sela I., Onaral B.

Conference Paper

2014

Investigation of Hemodynamic Changes during General Anesthesia via Functional Near Infrared Spectroscopy

Abstract


Citation

Hernandez G., Izzetoglu K, Osbakken M., Izzetoglu M., Green M., Sihna A., Onaral B., “Investigation of Hemodynamic Changes during General Anesthesia via Functional Near Infrared Spectroscopy,” fNIRS Conference, 2014.
[ ]

Hernandez G., Izzetoglu K, Osbakken M., Izzetoglu M., Green M., Sihna A., Onaral B.

Conference Paper

2014

Applying Functional Near Infrared (fNIR) Spectroscopy to Enhance MIS Research

Abstract

This review paper introduces the emerging technology of optical brain imaging, also known as functional near infrared (fNIR) spectroscopy, and discusses its potential role in enhancing theory and methodology used in MIS research. We discuss basic fNIR principles including the technique’s safe and portable nature, which allows ambulatory brain activity assessment in real world environments. We then touch on the neural correlates that fNIR measures, and the cortical oxygenation changes in the dorsal and anterior regions of the prefrontal cortex. We compare fNIR with traditional neuroimaging methods such as fMRI and PET. We also list case studies, future directions, and potential approaches relevant to MIS. fNIR may be used to inform theory and improve assessments in MIS-based studies, including informing theory, by identifying neural correlates, studying constructs that could not easily if at all be measured with traditional methods, applying objective constructs that subjects are unaware of, and designing better surveys.


Citation

Gefen D., Ayaz, H, Onaral, B. (2014) Applying Functional Near Infrared (fNIR) Spectroscopy to Enhance MIS Research, AIS Transactions of Human Computer Interaction, (6)2 pp 53-71
[ link ]

Gefen D., Ayaz, H, Onaral, B.

Journal

2014

Differentiating functions of the lateral and medial prefrontal cortex in motor response inhibition

Abstract

The right inferior frontal gyrus is generally considered a critical region for motor response inhibition. Recent studies, however, suggest that the role of this cortical area in response inhibition may be overstated and that the contributions of other aspects of the prefrontal cortex are often overlooked. The current study used optical imaging to identify regions of the prefrontal cortex beyond the right inferior frontal gyrus which may serve to support motor response inhibition. Forty-three right-handed healthy adults completed a manual Go/No-Go task while evoked oxygenation of the prefrontal cortex was measured using 16-channel functional near-infrared spectroscopy. During motor response inhibition, the right inferior frontal gyrus, and to a lesser extent the homologous contralateral region, showed increased activation relative to a baseline task. Conversely, the medial prefrontal cortex was significantly deactivated, and the extent of reduced activity in this region was associated with fewer errors on the response inhibition task. These findings suggest a more substantial role of the left inferior frontal gyrus in response inhibition and possibly a distinct function of the middle frontal gyrus subserving error detection on manual motor control tasks.


Citation

Rodrigo, A., Di Domenico, S. I., Ayaz, H., Gulrajani, S., Lam, J., & Ruocco, A. C. (2014). Differentiating functions of the lateral and medial prefrontal cortex in motor response inhibition. NeuroImage. Volume 85, Part 1, pp423–431 doi:10.1016/j.neuroimage.2013.01.059
[ link ]

Rodrigo, A., Di Domenico, S. I., Ayaz, H., Gulrajani, S., Lam, J., & Ruocco, A. C.

Journal

2014

Enhancing Dual-Task Performance with Verbal and Spatial Working Memory Training: Continuous Monitoring of Cerebral Hemodynamics with NIRS

Abstract

To better understand the mechanisms by which working memory training can augment human performance we continuously monitored trainees with near infrared spectroscopy (NIRS) while they performed a dual verbal–spatial working memory task. Linear mixed effects models were used to model the changes in cerebral hemodynamic response as a result of time spent training working memory. Nonlinear increases in left dorsolateral prefrontal cortex (DLPFC) and right ventrolateral prefrontal cortex (VLPFC) were observed with increased exposure to working memory training. Adaptive and yoked training groups also showed differential effects in rostral prefrontal cortex with increased exposure to working memory training. There was also a significant negative relationship between verbal working memory performance and bilateral VLPFC activation. These results are interpreted in terms of decreased proactive interference, increased neural efficiency, reduced mental workload for stimulus processing, and increased working memory capacity with training.


Citation

McKendrick, R., Ayaz, H., Olmstead, R., & Parasuraman, R. (2014). Enhancing Dual-Task Performance with Verbal and Spatial Working Memory Training: Continuous Monitoring of Cerebral Hemodynamics with NIRS. Neuroimage. Volume 85, Part 3, pp1014–1026 doi: 10.1016/j.neuroimage.2013.05.103
[ link ]

McKendrick, R., Ayaz, H., Olmstead, R., & Parasuraman, R.

Journal

2014

Near-infrared spectroscopic assessment of in-vivo prefrontal activation in public speaking anxiety: A preliminary investigation

Abstract

Public-speaking anxiety (PSA) may be associated with changes in functional activation of the right dorsolateral prefrontal cortex (DLPFC) during public speaking tasks. Research on the neural underpinnings of this disorder is limited by the physical restrictions imposed by conventional neuroimaging techniques. This study examined the feasibility of functional near-infrared spectroscopy (fNIRS) to investigate activation of the DLPFC in vivo while individuals gave a speech. Adults with PSA (n = 19) were assessed using self-rated anxiety measures during the anticipation and performance of a public speech while DLPFC activation was measured using fNIRS. Individuals showed bilateral changes in the DLPFC during both anticipation of and actual delivery of the speech. Only changes in blood volume in the right DLPFC were associated with higher subjective reports of anxiety during the speaking task. Results add to prior research examining DLPFC activation in generalized social anxiety disorder, and extend these findings to PSA for the first time. These findings highlight the utility of fNIRS for measuring cortical activation in vivo during social interactions. (PsycINFO Database Record (c) 2014 APA, all rights reserved)


Citation

Near-infrared spectroscopic assessment of in vivo prefrontal activation in public speaking anxiety: A preliminary study. Glassman, Lisa H.; Herbert, James D.; Forman, Evan M.; Bradley, Lauren E.; Izzetoglu, Meltem; Ruocco, Anthony C.; Goldstein, Stephanie P. Psychology of Consciousness: Theory, Research, and Practice, Vol 1(3), Sep 2014, 271-283. http://dx.doi.org/10.1037/cns0000009
[ link ]

L.H. Glassman, J.D. Herbert, E.M. Forman, L.E. Bradley, M. Izzetoglu, A.C. Ruocco, S.P. Goldstein

Journal

2014

Pupillometry Based System for ADD/ADHD Pharmacotherapy

Abstract

In the present state of the art, there is no convenient, non-invasive, cost-effective way to quantify the pharmacodynamic effects of a particular drug used in the treatment of Attention Deficit Disorder (ADD) and Attention Deficit Hyperactivity Disorder (ADHD), at a particular dose, in a given patient. Here we propose a novel, pupillometry-based system that can objectively, reproducibly, and non-invasively quantify the effects of stimulant drugs on the central nervous system (CNS) of patients with ADD/ADHD.


Citation

Johnson A., Morford M., Hirsh R., Head L., Izzetoglu M., "Pupillometry Based System for ADD/ADHD Pharmacotherapy," IEEE EMBS Conference, 2014
[ link ]

Johnson A., Morford M., Hirsh R., Head L., Izzetoglu M.

Conference Paper

2014

UAV Operators Workload Assessment by Optical Brain Imaging Technology (fNIR)

Abstract

The use of unmanned aerial vehicles (UAVs) is expected to increase exponentially over the next few years. UAV ground operators are required to acquire skills quickly and completely, with a level of expertise that builds the operator’s confidence in his/her ability to control the UAV under adverse conditions. As UAVs are held to increasingly higher standards of efficiency and safety, operators are routinely required to perform more informationally dense and cognitively demanding tasks, resulting in increased cognitive workloads during operation. Functional brain monitoring offers the potential to help UAV operators meet these challenges. Recent research has demonstrated the utility of near- infrared-based functional brain imaging systems (fNIRs) for the purpose of monitoring frontal cortical areas that support executive functions (attention, working memory, response monitoring). This technology provides portable, safe, affordable, noninvasive, and minimally intrusive monitoring systems with rapid application times for continuous measures of cortical activity. fNIR technology allows continuous monitoring of operators during training as they develop expertise, as well as the capacity to monitor their cognitive workload under operational conditions while controlling UAVs in critical missions. This chapter discusses the utilization of fNIR in the monitoring of a cognitive workload during UAV operation, and as an objective measure of expertise development, that is, the transition from novice to expert during operator training.


Citation

Izzetoglu, K., Ayaz, H., Hing, J., Shewokis, P., Bunce, S., Oh, P., & Onaral, B. (2014). UAV Operators Workload Assessment by Optical Brain Imaging Technology (fNIR). In K. P. Valavanis & G. J. Vachtsevanos (Eds.), Handbook of Unmanned Aerial Vehicles (pp. 2475-2500): Springer Netherlands.
[ link ]

Izzetoglu, K., Ayaz, H., Hing, J., Shewokis, P., Bunce, S., Oh, P., & Onaral, B.

Book Chapter

2014

Assessment of Prefrontal Cortex Activity in Amyotrophic Lateral Sclerosis Patients with Functional Near Infrared Spectroscopy

Abstract


Citation

Ayaz, H., Shewokis, P. A., Scull, L., Libon, D., J. , Feldman, S., Eppig, J., Onaral, B., Heiman-Patterson, T. (2014). Assessment of Prefrontal Cortex Activity in Amyotrophic Lateral Sclerosis Patients with Functional Near Infrared Spectroscopy. Journal of Neuroscience and Neuroengineering, 3(1), 41-51. doi: 10.1166/jnsne.2014.1095
[ link ]

Ayaz, H., Shewokis, P. A., Scull, L., Libon, D., J. , Feldman, S., Eppig, J., Onaral, B., Heiman-Patterson, T.

Journal

2014

Cognitive Workload and Learning Assessment During the Implementation of a Next-Generation Air Traffic Control Technology Using Functional Near-Infrared Spectroscopy

Abstract


Citation

Harrison, J., Izzetoglu, K., Ayaz, H., Willems, B., Hah, S., Ahlstrom, U., Woo, H., Shewokis, P. A. Bunce, S. C., Onaral, B. (2014). Cognitive Workload and Learning Assessment During the Implementation of a Next-Generation Air Traffic Control Technology Using Functional Near-Infrared Spectroscopy. Human-Machine Systems, IEEE Transactions on, 44(4), 429 - 440 doi: 10.1109/THMS.2014.2319822
[ link ]

Harrison, J., Izzetoglu, K., Ayaz, H., Willems, B., Hah, S., Ahlstrom, U., Woo, H., Shewokis, P. A. Bunce, S. C., Onaral, B.

Journal

2014

A Problem-Solving Task Specialized for Functional Neuroimaging: Validation of the Scarborough adaptation of the Tower of London (S-TOL) using Near-Infrared Spectroscopy

Abstract


Citation

Ruocco, A. C., Rodrigo, A. H., Lam, J., Di Domenico, S., Graves, B., & Ayaz, H. (2014). A Problem-Solving Task Specialized for Functional Neuroimaging: Validation of the Scarborough adaptation of the Tower of London (S-TOL) using Near-Infrared Spectroscopy. Frontiers in Human Neuroscience, 8. doi: 10.3389/fnhum.2014.00185
[ link ]

Ruocco, A. C., Rodrigo, A. H., Lam, J., Di Domenico, S., Graves, B., & Ayaz, H.

Journal

2014

Neuroimaging of Mobility in Aging: A Targeted Review

Abstract


Citation

Holtzer, R., Epstein, N., Mahoney, J. R., Izzetoglu, M., & Blumen, H. M. (2014). Neuroimaging of Mobility in Aging: A Targeted Review. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, glu052.
[ link ]

Holtzer, R., Epstein, N., Mahoney, J. R., Izzetoglu, M., & Blumen, H. M.

Journal

2013

Verbal working memory impairments following traumatic brain injury: an fNIRS investigation

Abstract

The construct of working memory and its reliance on dorsolateral prefrontal cortex (DLPFC) have been the focus of many studies in healthy subjects and in clinical populations. However, transfer of knowledge gained from cognitive science studies to clinical applications can be a challenging goal. This scarce cross-dissemination may be partially due to the use of 'tools' that are limited in their ability to generate meaningful information about impairments in clinical groups. To this end, this paper investigates the use of functional near-infrared spectroscopy (fNIRS), which offers unique opportunities for recording neuroactivation. Specifically, we examine measures of the DLPFC hemodynamic response during a working memory task in adults with traumatic brain injury (TBI) and healthy controls. Analysis of hemodynamic measures showed significant differences between the two groups, even without differences in behavioral performance. Additional subtle disparities were linked to levels of performance in TBI and healthy subjects. fNIRS hemodynamic measures may therefore provide novel information to existing theories and knowledge of the working memory construct. Future studies may further define these subtle differences captured by fNIRS to help identify which components affect inter-individual variations in performance and could play a contributing role in the choice and planning of neurorehabilitation interventions targeting working memory.


Citation

A.C.R. Merzagora, M. Izzetoglu, B. Onaral, M.T. Schultheis, “Verbal working memory impairments following traumatic brain injury: an fNIRS investigation,” Brain imaging and behavior, 1-14, 2013.
[ link ]

A.C.R. Merzagora, M. Izzetoglu, B. Onaral, M.T. Schultheis

Journal

2013

Continuous monitoring of brain dynamics with functional near infrared spectroscopy as a tool for neuroergonomic research: Empirical examples and a technological development

Abstract

Functional near infrared spectroscopy (fNIRS) is a non-invasive, safe, and portable optical neuroimaging method that can be used to assess brain dynamics during skill acquisition and performance of complex work and everyday tasks. In this paper we describe neuroergonomic studies that illustrate the use of fNIRS in the examination of training-related brain dynamics and human performance assessment. We describe results of studies investigating cognitive workload in air traffic controllers, acquisition of dual verbal-spatial working memory skill, and development of expertise in piloting unmanned vehicles. These studies used conventional fNIRS devices in which the participants were tethered to the device while seated at a workstation. Consistent with the aims of mobile brain imaging (MoBI), we also describe a compact and battery-operated wireless fNIRS system that performs with similar accuracy as other established fNIRS devices. Our results indicate that both wired and wireless fNIRS systems allow for the examination of brain function in naturalistic settings, and thus are suitable for reliable human performance monitoring and training assessment.


Citation

Ayaz, H., Onaral, B., Izzetoglu, K., Shewokis, P. A., McKendrick, R., & Parasuraman, R. (2013). Continuous monitoring of brain dynamics with functional near infrared spectroscopy as a tool for neuroergonomic research: Empirical examples and a technological development. Frontiers in Human Neuroscience, 7, 1-13. doi: 10.3389/fnhum.2013.00871
[ link ]

Ayaz, H., Onaral, B., Izzetoglu, K., Shewokis, P. A., McKendrick, R., & Parasuraman, R.

Journal

2013

Molecular concentration of deoxyHb in human prefrontal cortex predicts the emergence and suppression of consciousness

Abstract

Abstract Coming Soon...


Citation

Leon-Dominguez, U., Izzetoglu, M., Leon-Carrion, J., Solís-Marcos, I., Garcia-Torrado, F. J., Forastero-Rodríguez, A., Mellado-Miras, P., Villegas-Duque, D., Lopez-Romero, J. L., Onaral, B., Izzetoglu, K. (2013). Molecular concentration of deoxyHb in human prefrontal cortex predicts the emergence and suppression of consciousness.. Neuroimage,
[ ]

Leon-Dominguez, U., Izzetoglu, M., Leon-Carrion, J., Solís-Marcos, I., Garcia-Torrado, F. J., Forastero-Rodríguez, A., Mellado-Miras, P., Villegas-Duque, D., Lopez-Romero, J. L., Onaral, B., Izzetoglu, K.

Journal

2013

Functional Near-Infrared Spectroscopy for the Measurement of Propofol Effects in Conscious Sedation during Outpatient Elective Colonoscopy

Abstract

Abstract coming soon.


Citation

Curtin, A., Izzetoglu, K., Reynolds, J., Menon, R., Izzetoglu, M., Osbakken, M., & Onaral, B. (2013). Functional Near-Infrared Spectroscopy for the Measurement of Propofol Effects in Conscious Sedation during Outpatient Elective Colonoscopy.. Neuroimage,
[ ]

Curtin, A., Izzetoglu, K., Reynolds, J., Menon, R., Izzetoglu, M., Osbakken, M., & Onaral, B.

Journal

2013

Assessment of Fatigue in Brain Computer Interface Users

Abstract

The brain computer interface (BCI) is an alternative communication method for those living with physically disabling conditions such as neuromuscular disorders, traumatic brain injuries, and stroke that uses a cap with embedded electrodes to read electroencephalography (EEG) signals and uses them to control a computer. Specifically, the P300, a naïve response to target stimuli, is used to select letters from a matrix. The system provides those with no neuromuscular control with a novel channel for communication. To date, little to no work has investigated the effects of mental fatigue arising from short-term BCI use on the signals that are used to control the BCI itself. Methods typically used to characterize fatigue in EEG signals employ spectral analysis techniques that are confounded by periodic stimulus presentation in the BCI protocol. The characterization of the effects of fatigue could enable developers to create BCI systems that compensate for or prevent fatigue, which could improve overall usability. To date, little to no work has investigated the effects of mental fatigue arising from short-term BCI use on the signals that are used to control the BCI itself. Methods typically used to characterize fatigue in EEG signals employ spectral analysis techniques that are confounded by periodic stimulus presentation in the BCI protocol. The characterization of the effects of fatigue could enable developers to create BCI systems that compensate for or prevent fatigue, which could improve overall usability. To date, little to no work has investigated the effects of mental fatigue arising from short-term BCI use on the signals that are used to control the BCI itself. Methods typically used to characterize fatigue in EEG signals employ spectral analysis techniques that are confounded by periodic stimulus presentation in the BCI protocol. The characterization of the effects of fatigue could enable developers to create BCI systems that compensate for or prevent fatigue, which could improve overall usability. Eleven healthy subjects from the Philadelphia region participated in trials using the P300-based BCI alongside cognitive and self-reported measures of fatigue under informed consent. The changes in EEG signals related to increased mental fatigue occured in a predictable manner, forming a "checkmark" pattern in P300 amplitude across BCI trials, mirroring the results of a 20006 study investigating fatigue's effects on the P300 signal specifically. Future work may incorporate this pattern into adaptive BCI systems capable of detecting and compensating for mental fatigue during long-term BCI use.


Citation

Petaccio, V., Ayaz, H, (2013) Assessment of Fatigue in Brain Computer Interface Users, Masters Degree Thesis, Biomedical Engineering, Drexel University,
[ link ]

Petaccio, V., Ayaz, H.

Master's Thesis

2013

EEG band powers for characterizing user engagement in P300 BCI

Abstract

An asynchronous P300-based brain computer interface (BCI) allows users to operate the BCI at their own pace by being able to detect a user’s engagement. In our previous work, band powers has been shown to be able to provide additional information for characterizing user engagement and yielded better performance compared to the use of only the amplitudes of event-related potentials. In this follow up study, 19 subjects participated in an experiment which was designed to further evaluate additional predictors of user engagement using band powers. In addition to the regular P300 attended condition, two not-engaged conditions were considered: one with the P300 stimulus matrix still shown (control 1) and the other with stimulus covered by a blank screen (control 2). Alpha and beta band activities decreased in the order of control 2, control 1 and attended. Furthermore, the attended condition had lower delta activity compared to the control conditions. Classification results indicated that band powers were better at differentiating attended and control 2 conditions. Using band powers as additional features resulted in a moderate to moderately large (dz= 0.52 to 0.74) improvement over the classification of the two conditions.


Citation

Liu, Y., Ayaz, H., Onaral, B., Shewokis, P.A. (2013) EEG band powers for characterizing user engagement in P300 BCI, Proc. 6th International IEEE/EMBS Conf on Neural Engineering (NER), San Diago, CA
[ link ]

Liu, Y., Ayaz, H., Onaral, B., Shewokis, P.A.

Conference Paper

2013

Enhancing Dual-Task Performance with Verbal and Spatial Working Memory Training: Continuous Monitoring of Cerebral Hemodynamics with NIRS

Abstract

To better understand the mechanisms by which working memory training can augment human performance we continuously monitored trainees with near infrared spectroscopy (NIRS) while they performed a dual verbal–spatial working memory task. Linear mixed effects models were used to model the changes in cerebral hemodynamic response as a result of time spent training working memory. Nonlinear increases in left dorsolateral prefrontal cortex (DLPFC) and right ventrolateral prefrontal cortex (VLPFC) were observed with increased exposure to working memory training. Adaptive and yoked training groups also showed differential effects in rostral prefrontal cortex with increased exposure to working memory training. There was also a significant negative relationship between verbal working memory performance and bilateral VLPFC activation. These results are interpreted in terms of decreased proactive interference, increased neural efficiency, reduced mental workload for stimulus processing, and increased working memory capacity with training.


Citation

McKendrick, R., Ayaz, H., Olmstead, R., & Parasuraman, R. (2013). Enhancing Dual-Task Performance with Verbal and Spatial Working Memory Training: Continuous Monitoring of Cerebral Hemodynamics with NIRS. Neuroimage. doi: 10.1016/j.neuroimage.2013.05.103
[ link ]

McKendrick, R., Ayaz, H., Olmstead, R., & Parasuraman, R.

Journal

2013

Differentiating functions of the lateral and medial prefrontal cortex in motor response inhibition

Abstract

The right inferior frontal gyrus is generally considered a critical region for motor response inhibition. Recent studies, however, suggest that the role of this cortical area in response inhibition may be overstated and that the contributions of other aspects of the prefrontal cortex are often overlooked. The current study used optical imaging to identify regions of the prefrontal cortex beyond the right inferior frontal gyrus which may serve to support motor response inhibition. Forty-three right-handed healthy adults completed a manual Go/No-Go task while evoked oxygenation of the prefrontal cortex was measured using 16-channel functional near-infrared spectroscopy. During motor response inhibition, the right inferior frontal gyrus, and to a lesser extent the homologous contralateral region, showed increased activation relative to a baseline task. Conversely, the medial prefrontal cortex was significantly deactivated, and the extent of reduced activity in this region was associated with fewer errors on the response inhibition task. These findings suggest a more substantial role of the left inferior frontal gyrus in response inhibition and possibly a distinct function of the middle frontal gyrus subserving error detection on manual motor control tasks.


Citation

Rodrigo, A., Di Domenico, S. I., Ayaz, H., Gulrajani, S., Lam, J., & Ruocco, A. C. (2013). Differentiating functions of the lateral and medial prefrontal cortex in motor response inhibition. NeuroImage. doi:10.1016/j.neuroimage.2013.01.059
[ link ]

Rodrigo, A., Di Domenico, S. I., Ayaz, H., Gulrajani, S., Lam, J., & Ruocco, A. C.

Journal

2013

Functional near-infrared spectroscopy-based correlates of prefrontal cortical dynamics during a cognitive-motor executive adaptation task

Abstract

This study investigated changes in brain hemodynamics, as measured by functional near infrared spectroscopy, during performance of a cognitive-motor adaptation task. The adaptation task involved the learning of a novel visuomotor transformation (a 60◦ counterclockwise screen-cursor rotation), which required inhibition of a prepotent visuomotor response. A control group experienced a familiar transformation and thus, did not face any executive challenge. Analysis of the experimental group hemodynamic responses revealed that the performance enhancement was associated with a monotonic reduction in the oxygenation level in the prefrontal cortex. This finding confirms and extends functional magnetic resonance imaging and electroencephalography studies of visuomotor adaptation and learning. The changes in prefrontal brain activation suggest an initial recruitment of frontal executive functioning to inhibit prepotent visuomotor mappings followed by a progressive de-recruitment of the same prefrontal regions. The prefrontal hemodynamic changes observed in the experimental group translated into enhanced motor performance revealed by a reduction in movement time, movement extent, root mean square error and the directional error. These kinematic adaptations are consistent with the acquisition of an internal model of the novel visuomotor transformation. No comparable change was observed in the control group for either the hemodynamics or for the kinematics. This study (1) extends our understanding of the frontal executive processes from the cognitive to the cognitive-motor domain and (2) suggests that optical brain imaging can be employed to provide hemodynamic based-biomarkers to assess and monitor the level of adaptive cognitive-motor performance.


Citation

Gentili, R. J., Shewokis, P. A., Ayaz, H., & Contreras-Vidal, J. L. (2013). Functional near-infrared spectroscopy-based correlates of prefrontal cortical dynamics during a cognitive-motor executive adaptation task. Frontiers in Human Neuroscience, 7. doi: 10.3389/fnhum.2013.00277
[ link ]

Gentili, R. J., Shewokis, P. A., Ayaz, H., & Contreras-Vidal, J. L.

Journal

2013

Neural correlates of cognitive decline in ALS: An fNIRS study of the prefrontal cortex

Abstract

Functional near infrared spectroscopy (fNIRS) is a clinically feasible functional neuroimaging modality for detecting early cortical changes due to neurodegenerative diseases that affect cognition. The objective of this preliminary investigation was to test for reduced prefrontal activity in persons with cognitive impairments due to amyotrophic lateral sclerosis (ALS). Participants were required to complete two N-back working memory tasks of increasing complexity during fNIRS recordings. Five participants with ALS and age- and gender-matched healthy participants comprised the experimental and control groups, respectively. Significant reductions in prefrontal oxygenation levels were observed for the left and right hemispheres in the ALS group compared to the control group. Reduced prefrontal activation despite intact behavioral performance for a working memory task may suggest early neuroanatomical, neurophysiological and/or compensatory mechanisms in affected individuals. The fNIRS-derived oxygenation measure shows promise as a sensitive neural marker to identify early neuropsychological impairments due to ALS.


Citation

Kuruvilla, M. S., Green, J. R., Ayaz, H., & Murman, D. L. (2013). Neural correlates of cognitive decline in ALS: An fNIRS study of the prefrontal cortex. Cognitive Neuroscience, 4(2), 115-121. doi: 10.1080/17588928.2013.797889
[ link ]

Kuruvilla, M. S., Green, J. R., Ayaz, H., & Murman, D. L.

Journal

2013

Differential prefrontal response during natural and synthetic speech perception: An fNIR based neuroergonomics study

Abstract

Synthetic speech has a growing role in human computer interaction and automated systems with the emergence of ubiquitous computing such as smart phones, car multimedia control and navigation systems. Cognitive processing costs associated with comprehension of synthetic speech relative to comprehension of natural speech have been demonstrated with behavioral (reaction time, accuracy, etc.) and self-reported (ratings, etc.) measures. In this neuroergonomics study, we have used optical brain imaging (fNIR: functional near infrared spectroscopy) to capture the brain activation of participants while they were listening to speech with varied quality, as well as natural speech. Results indicated a differential hemodynamic response with speech quality. As fNIR systems are safe, portable and record brain activation in real world settings, fNIR is a practical and minimally intrusive assessment tool for user experience researchers and can provide an objective metric for the design and development of next generation synthetic speech systems.


Citation

Ayaz, H., Crawford, P., Curtin, A., Syed, M., Onaral, B., Beltman, W.M., Shewokis, P.A. (2013) Differential prefrontal response during natural and synthetic speech perception: An fNIR based neuroergonomics study, In D. Schmorrow & C. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 8027, pp. 241-249): Springer Berlin Heidelberg.
[ link ]

Ayaz, H., Crawford, P., Curtin, A., Syed, M., Onaral, B., Beltman, W.M., Shewokis, P.A.

Book Chapter

2013

Towards a hybrid P300-based BCI using simultaneous fNIR and EEG

Abstract

Next generation brain computer interfaces (BCI) are expected to provide robust and continuous control mechanism. In this study, we assessed integration of optical brain imaging (fNIR: functional near infrared spectroscopy) to a P300-BCI for improving BCI usability by monitoring cognitive workload and performance. fNIR is a safe and wearable neuroimaging modality that tracks cortical hemodynamics in response to sensory, motor, or cognitive activation. Eight volunteers participated in the study where simultaneous EEG and 16 optode fNIR from anterior prefrontal cortex were recorded while participants engaged with the P300-BCI for spatial navigation. The results showed a significant response in fNIR signals during high, medium and low performance indicating a positive correlation between prefrontal oxygenation changes and BCI performance. This preliminary study provided evidence that the performance of P300-BCI can be monitored by fNIR which in turn can help improve the robustness of the BCI classification.


Citation

Liu, Y., Ayaz, H., Curtin, A., Onaral, B., Shewokis, P.A. (2013) Towards a hybrid P300-based BCI using simultaneous fNIR and EEG, In D. Schmorrow & C. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 8027, pp. 335-344): Springer Berlin Heidelberg.
[ link ]

Liu, Y., Ayaz, H., Curtin, A., Onaral, B., Shewokis, P.A.

Book Chapter

2013

Brain in the Loop Learning using Functional Near Infrared Spectroscopy

Abstract

The role of practice is crucial in the skill acquisition process and for assessments of learning. In this study, we used a portable neuroimaging technique, functional near infrared (fNIR) spectroscopy for monitoring prefrontal cortex activation during learning of spatial navigation tasks throughout 11 days of training and testing. Two different tasks orders, blocked and random, were used to test the effect of the practice schedule on the acquisition and transfer of 3D computer mazes. Results indicated variable decreases in the hemodynamic response during the initial days of practice. Although there were no differences in mean oxygenation for the practice orders across acquisition the random practice order used less oxygenation than the blocked order for the more difficult tasks in the transfer phase Use of brain activation and behavioral measures provides can provide a more accurate depiction of the learning process. Since fNIR systems are safe, portable and record brain activation in ecologically valid settings, fNIR can contribute to future learning settings for assessment and personalization of the training regimen.


Citation

Shewokis, P.A., Ayaz, H., Curtin, A., Izzetoglu, K., Onaral, B.(2013) Brain in the Loop Learning using Functional Near Infrared Spectroscopy, In D. Schmorrow & C. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 8027, pp. 381-389): Springer Berlin Heidelberg.
[ link ]

Shewokis, P.A., Ayaz, H., Curtin, A., Izzetoglu, K., Onaral, B.

Book Chapter

2013

Human Performance Assessment Study in Aviation Using Functional Near Infrared Spectroscopy

Abstract

Functional near infrared (fNIR) spectroscopy is a field-deployable optical neuroimaging technology that provides a measure of the prefrontal cortex’s cerebral hemodynamics in response to the completion of sensory, motor, or cognitive tasks. Technologies such as fNIR could provide additional performance metrics directly from brain-based measures to assess safety and performance of operators in high-risk fields. This paper reports a case study utilizing a continuous wave fNIR technology deployed in a real-time air traffic control (ATC) setting to evaluate the cognitive workload of certified professional controllers (CPCs) during the deployment of one of the Federal Aviation Administration’s (FAA’s) Next Generation (NextGen) technologies.


Citation

Harrison, J., Izzetoglu, K., Ayaz, H., Willems, B., Hah, S., Woo, H., Shewokis, P.A., Bunce, S.C., Onaral, B. (2013) Human Performance Assessment Study in Aviation Using Functional Near Infrared Spectroscopy, In D. Schmorrow & C. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 8027, pp. 433-442): Springer Berlin Heidelberg.
[ link ]

Harrison, J., Izzetoglu, K., Ayaz, H., Willems, B., Hah, S., Woo, H., Shewokis, P.A., Bunce, S.C., Onaral, B.

Book Chapter

2013

Functional Near-Infrared Spectroscopy in Addiction Treatment: Preliminary Evidence as a Biomarker of Treatment Response

Abstract

There is growing evidence that there are functional changes in the brains of individuals with substance use disorders. Numerous studies utilizing functional magnetic resonance imaging (fMRI) have shown that drug cues elicit increased regional blood flow in reward-related brain areas among addicted participants that is not found among normal controls. This finding has prompted leading investigators to suggest fMRI might be useful as a diagnostic or prognostic biomarker of addiction severity. However, fMRI is too costly for routine use in most treatment facilities. Functional near-infrared spectroscopy (fNIRs) offers an alternative neuroimaging modality that is safe, affordable, and patient-friendly. This manuscript reviews evidence that fNIRs can be used to differentiate prefrontal cortical responses of current alcohol dependent participants from alcohol dependent patients in treatment for 90-180 days. Differential responses to both alcohol and natural reward cues in both groups suggests fNIRs might serve as a clinic-friendly neuroimaging technology to inform clinical practice.


Citation

Bunce, S.C., Harris, J., Izzetoglu, K., Ayaz, H., Izzetoglu, M., Pourrezaei, K., Onaral, B., (2013) Functional Near-Infrared Spectroscopy in Addiction Treatment: Preliminary Evidence as a Biomarker of Treatment Response, In D. Schmorrow & C. Fidopiastis (Eds.), Foundations of Augmented Cognition (Vol. 8027, pp. 250-258): Springer Berlin Heidelberg.
[ link ]

Bunce, S.C., Harris, J., Izzetoglu, K., Ayaz, H., Izzetoglu, M., Pourrezaei, K., Onaral, B.

Book Chapter

2013

The Use of Functional Near Infrared Spectroscopy (fNIRS) to Assess Cognitive Workload of Air Traffic Controllers

Abstract

The performance of a Certified Professional Controller (CPC) can have a critical impact on safety. A specific concern is that a high cognitive load has been associated with performance decrement. Thus, it is important to continuously monitor and accurately assess CPC cognitive load. The purpose of the study was to evaluate the effectiveness of Conflict Resolution Advisory (CRA), automation which provides CPCs with resolutions to avoid conflicts. In this study, we used functional Near Infrared Spectroscopy (fNIRS) to index cognitive workload of 12 CPCs from En Route centers. Results indicate that fNIRS measures were sensitive to air traffic level, but we did not find significant differences across CRA conditions. In addition, we conducted analysis on fNIRS data time-locked to selected events such as clearance commands. With this event-related analysis, we found differences among CRA conditions for different events. The findings indicate that fNIRS can be a potential objective workload measurement tool in the air traffic control domain.


Citation

Woo, H., Willems, B., Harrison, J., Izzetoglu, K., Hah, S., & Ayaz, H. (2013) The Use of Functional Near Infrared Spectroscopy (fNIRS) to Assess Cognitive Workload of Air Traffic Controllers, 17th International Symposium on Aviation Psychology, May 6 – May 9, 2013, Wright State University, Dayton, Ohio, USA.
[ link ]

Woo, H., Willems, B., Harrison, J., Izzetoglu, K., Hah, S., & Ayaz, H.

Conference Paper

2012

Exploring frontal asymmetry using functional near-infrared spectroscopy: a preliminary study of the effects of social anxiety during interaction and performance tasks

Abstract

Preliminary studies examining brain function associated with social anxiety suggest the possibility of right-sided prefrontal activation associated with phobic stimulation. Although most existing neuroimaging techniques preclude participants from engaging in ecologically valid social tasks during assessment, functional near-infrared spectroscopy (fNIRS) is a promising new technique that permits such assessment. The present study investigated the utility of the fNIRS procedure and explored frontal asymmetry during in vivo social challenge tasks among female undergraduate students who scored in top and bottom percentiles on a social anxiety screening measure. Results revealed that participants in both groups experienced a significant increase in concentration of blood volume and oxygenated hemoglobin in the right hemisphere compared to the left hemisphere while giving a speech. Non-hemispheric effects were also observed. In addition, the high anxiety group showed a non-significant trend toward greater right frontal activity than the low anxiety group. This study highlights the utility of the fNIRS device in successfully assessing real-time changes in cerebrovascular response as a function of naturalistic social behavior, and supports the potential utility of this technology in the study of the neurophysiology of social anxiety.


Citation

L.A. Tuscan, J.D. Herbert, E.M. Forman, A.S. Juarascio, M. Izzetoglu, M. Schultheis, "Exploring frontal asymmetry using functional near-infrared spectroscopy: a preliminary study of the effects of social anxiety during interaction and performance tasks," Brain Imaging and Behavior, 7(2):140-53, 2012.
[ link ]

L.A. Tuscan, J.D. Herbert, E.M. Forman, A.S. Juarascio, M. Izzetoglu, M. Schultheis

Journal

2012

Hemodynamic response to repeated noxious cold pressor tests measured by functional near infrared spectroscopy on forehead

Abstract

The objective of this research was to assess the utility of a simple near infrared spectroscopy (NIRS) technology for objective assessment of the hemodynamic response to acute pain. For this exploration, we used functional near infrared spectroscopy (fNIRS) to measure the hemodynamic response on the forehead during three trials of a cold pressor test (CPT) in 20 adults. To measure hemodynamic changes at the superficial tissues as well as the intracranial tissues, two configurations of 'far' and 'near' source-detector separations were used. We identified two features that were found to be fairly consistent across all subjects. The first feature was the change of total hemoglobin (THb) concentration in a given condition divided by the duration of that condition [Formula: see text]. Statistical analyses revealed that during the first CPT trial [Formula: see text] significantly changed from its baseline value in all channels. Also, adaptation to repeated CPTs was observed in both [Formula: see text] parameter and the reported post-stimulus pain rating scores. The second feature was the difference between the maximum and the minimum of the evoked changes in the THb concentration (ΔTHb). A significant correlation was observed between the post-stimulus pain rating score and ΔTHb at all channels. An asymmetrical activity was observed only at the 'far' channels. These results suggest that fNIRS can potentially be used as a reliable technique for the assessment of the hemodynamic response to tonic pain induced by the CPT.


Citation

K. Pourrezaei, Z. Barati, P.A. Shewokis, M. Izzetoglu, R. Polikar, G. Mychaskiw, " Hemodynamic response to repeated noxious cold pressor tests measured by functional near infrared spectroscopy on forehead," Annals of Biomedical Engineering, 41(2):223-237, 2012.
[ link ]

K. Pourrezaei, Z. Barati, P.A. Shewokis, M. Izzetoglu, R. Polikar, G. Mychaskiw

Journal

2012

A Functional Near-Infrared Spectroscopy Study of Lexical Decision Task Supports the Dual Route Model and the Phonological Deficit Theory of Dyslexia

Abstract

The dual route model (DRM) of reading suggests two routes of reading development: the phonological and the orthographic routes. It was proposed that although the two routes are active in the process of reading; the first is more involved at the initial stages of reading acquisition, whereas the latter needs more reading training to mature. A number of studies have shown that deficient phonological processing is a core deficit in developmental dyslexia. According to the DRM, when the Lexical Decision Task (LDT) is performed, the orthographic route should also be involved when decoding words, whereas it is clear that when decoding pseudowords the phonological route should be activated. Previous functional near-infrared spectroscopy (fNIR) studies have suggested that the upper left frontal lobe is involved in decision making in the LDT. The current study used fNIR to compare left frontal lobe activity during LDT performance among three reading-level groups: 12-year-old children, young adult dyslexic readers, and young adult typical readers. Compared to typical readers, the children demonstrated lower activity under the word condition only, whereas the dyslexic readers showed lower activity under the pseudoword condition only. The results provide evidence for upper left frontal lobe involvement in LDT and support the DRM and the phonological deficit theory of dyslexia.


Citation

I. Sela, M. Izzetoglu, K. Izzetoglu, B. Onaral, "A Functional Near-Infrared Spectroscopy Study of Lexical Decision Task Supports the Dual Route Model and the Phonological Deficit Theory of Dyslexia," Journal of Learning Disabilities, 2012.
[ link ]

I. Sela, M. Izzetoglu, K. Izzetoglu, B. Onaral

Journal

2012

Emerging economies, enduring partnerships

Abstract

Our instincts as well as the data of the world suggest that the conversion of scientific knowledge into social good and economic value creates well-being, prosperity, and peace, transcending cultural, disciplinary, or national boundaries. Forging innovation alliances that defy space and time and overcome political separation is a sure path to this end. But stakeholders around the world have not yet fully mastered the art and science of cultivating fruitful and long-lasting alliances between partners in advanced and advancing economies. As Drexel University prepares to host regional, national, and international guests at our inaugural Global Innovation Partnership week of activities, I share insights I’ve gained over the past two decades as an on-site facilitator of biomedical technology collaborations between scientists and other stakeholders in the United States and in countries with emerging economies.


Citation

Onaral B (2012). Emerging economies, enduring partnerships.. Science Translational Medicine, 4(158):158ed8.
[ link ]

Onaral B.

Journal

2012

A Working Memory Deficit among Dyslexic Readers with No Phonological Impairment as Measured Using the N-Back Task: An fNIR Study

Abstract

Abstract coming soon


Citation

Sela I, Izzetoglu M, Izzetoglu K, Onaral B (2012). A Working Memory Deficit among Dyslexic Readers with No Phonological Impairment as Measured Using the N-Back Task: An fNIR Study.. PLoS ONE, 7(11): e46527.
[ ]

Sela I, Izzetoglu M, Izzetoglu K, Onaral B

Journal

2012

Frontal lobe role in simple arithmetic calculations: An fNIR study

Abstract

Abstract coming soon...


Citation

Meiri, H., Sela, I., Nesher, P., Izzetoglu, M., Izzetoglu, K., Onaral, B., & Breznitz, Z. (2012). Frontal lobe role in simple arithmetic calculations: An fNIR study.. Neuroscience Letters, 510(1), 43-47.
[ ]

Meiri, H., Sela, I., Nesher, P., Izzetoglu, M., Izzetoglu, K., Onaral, B., & Breznitz, Z.

Journal

2012

In Search of Integrative Processes: Basic Psychological Need Satisfaction Predicts Medial Prefrontal Activation During Decisional Conflict

Abstract

Research has shown that people’s abilities to develop and act from a coherent sense of self are facilitated by satisfaction of the basic psychological needs for competence, relatedness, and autonomy. The present study utilized functional near infrared spectroscopy (fNIRS) to examine the effect of need satisfaction on activity in the medial prefrontal cortex (MPFC), a key region in processing information about the self. Participants completed a decision-making task (e.g., Which occupation would you prefer, dancer or chemist?) in which they made a series of forced choices according to their personal preferences. The degree of decisional conflict (i.e., choice difficulty) between the available response options was manipulated on the basis of participants’ unique preference ratings for the target stimuli, which were obtained prior to scanning. Need satisfaction predicted elevated MPFC activity during high-conflict relative to low-conflict situations, suggesting that one way need satisfaction may promote self-coherence is by enhancing the utilization of self-knowledge in the resolution of decisional conflicts.


Citation

Di Domenico, S. I., Fournier, M. A., Ayaz, H., & Ruocco, A. C. (2012). In Search of Integrative Processes: Basic Psychological Need Satisfaction Predicts Medial Prefrontal Activation During Decisional Conflict. Journal of Experimental Psychology: General, . doi: 10.1037/a0030257
[ link ]

Di Domenico, S. I., Fournier, M. A., Ayaz, H., & Ruocco, A. C.

Journal

2012

A Methodology for Validating Artifact Removal Techniques for Physiological Signals

Abstract

Artifact removal from physiological signals is an essential component of the biosignal processing pipeline. The need for powerful and robust methods for this process has become particularly acute as healthcare technology deployment undergoes transition from the current hospital-centric setting toward a wearable and ubiquitous monitoring environment. Currently, determining the relative efficacy and performance of the multiple artifact removal techniques available on real world data can be problematic, due to incomplete information on the uncorrupted desired signal. The majority of techniques are presently evaluated using simulated data, and therefore, the quality of the conclusions is contingent on the fidelity of the model used. Consequently, in the biomedical signal processing community, there is considerable focus on the generation and validation of appropriate signal models for use in artifact suppression. Most approaches rely on mathematical models which capture suitable approximations to the signal dynamics or underlying physiology and, therefore, introduce some uncertainty to subsequent predictions of algorithm performance. This paper describes a more empirical approach to the modeling of the desired signal that we demonstrate for functional brain monitoring tasks which allows for the procurement of a “ground truth” signal which is highly correlated to a true desired signal that has been contaminated with artifacts. The availability of this “ground truth,” together with the corrupted signal, can then aid in determining the efficacy of selected artifact removal techniques. A number of commonly implemented artifact removal techniques were evaluated using the described methodology to validate the proposed novel test platform.


Citation

Sweeney, K., Ayaz, H., Ward, T., Izzetoglu, M., McLoone, S., & Onaral, B. (2012). A Methodology for Validating Artifact Removal Techniques for Physiological Signals. Information Technology in Biomedicine, IEEE Transactions on, pp(99), 1-1. doi: 10.1109/titb.2012.2207400
[ link ]

Sweeney, K., Ayaz, H., Ward, T., Izzetoglu, M., McLoone, S., & Onaral, B.

Journal

2012

Tangram solved? Prefrontal cortex activation analysis during geometric problem solving

Abstract

Recent neuroimaging studies have implicated prefrontal and parietal cortices for mathematical problem solving. Mental arithmetic tasks have been used extensively to study neural correlates of mathematical reasoning. In the present study we used geometric problem sets (tangram tasks) that require executive planning and visuospatial reasoning without any linguistic representation interference. We used portable optical brain imaging (functional near infrared spectroscopy - fNIR) to monitor hemodynamic changes within anterior prefrontal cortex during tangram tasks. Twelve healthy subjects were asked to solve a series of computerized tangram puzzles and control tasks that required same geometric shape manipulation without problem solving. Total hemoglobin (HbT) concentration changes indicated a significant increase during tangram problem solving in the right hemisphere. Moreover, HbT changes during failed trials (when no solution found) were significantly higher compared to successful trials. These preliminary results suggest that fNIR can be used to assess cortical activation changes induced by geometric problem solving. Since fNIR is safe, wearable and can be used in ecologically valid environments such as classrooms, this neuroimaging tool may help to improve and optimize learning in educational settings.


Citation

Ayaz, H., Shewokis, P. A., Izzetoglu, M., Cakir, M. P., Onaral, B. (2012) Tangram solved? Prefrontal cortex activation analysis during geometric problem solving, 34th Annual International IEEE EMBS Conference, August 28 – September 1, 2012, San Diego, CA, USA.
[ link ]

Ayaz, H., Shewokis, P. A., Izzetoglu, M., Cakir, M. P., Onaral, B.

Conference Paper

2012

A P300-based EEG-BCI for Spatial Navigation Control

Abstract

Abstract Coming Soon...


Citation

Curtin, A., Ayaz, H., Liu, Y., Shewokis, P. A., Onaral, B. (2012) A P300-based EEG-BCI for Spatial Navigation Control, 34th Annual International IEEE EMBS Conference, August 28 – September 1, 2012, San Diego, CA, USA.
[ link ]

Curtin, A., Ayaz, H., Liu, Y., Shewokis, P. A., Onaral, B.

Conference Paper

2012

Detection of attention shift for asynchronous P300-based BCI

Abstract

Brain-computer interface (BCI) provides patients suffering from severe neuromuscular disorders an alternative way of interacting with the outside world. The P300-based BCI is among the most popular paradigms in the field and most current versions operate in synchronous mode and assume participant engagement throughout operation. In this study, we demonstrate a new approach for assessment of user engagement through a hybrid classification of ERP and band power features of EEG signals that could allow building asynchronous BCIs. EEG signals from nine electrode locations were recorded from nine participants during controlled engagement conditions when subjects were either engaged with the P3speller task or not attending. Statistical analysis of band power showed that there were significant contrasts of attending only for the delta and beta bands as indicators of features for user attendance classification. A hybrid classifier using ERP scores and band power features yielded the best overall performance of 0.98 in terms of the area under the ROC curve (AUC). Results indicate that band powers can provide additional discriminant information to the ERP for user attention detection and this combined approach can be used to assess user engagement for each stimulus sequence during BCI use.


Citation

Liu, Y., Ayaz, H., Curtin, A., Shewokis, P. A., Onaral, B. (2012) Detection of attention shift for asynchronous P300-based BCI, 34th Annual International IEEE EMBS Conference, August 28 – September 1, 2012, San Diego, CA, USA.
[ link ]

Liu, Y., Ayaz, H., Curtin, A., Shewokis, P. A., Onaral, B.

Conference Paper

2012

Using brain activity to predict task performance and operator efficiency

Abstract

The efficiency and safety of many complex human-machine systems are closely related to the cognitive workload and situational awareness of their human operators. In this study, we utilized functional near infrared (fNIR) spectroscopy to monitor anterior prefrontal cortex activation of experienced operators during a standard working memory and attention task, the n-back. Results indicated that task efficiency can be estimated using operator’s fNIR and behavioral measures together. Moreover, fNIR measures had more predictive power than behavioral measures for estimating operator’s future task performance in higher difficulty conditions.


Citation

Ayaz, H., Bunce, S., Shewokis, P. A., Izzetoglu, K., Willems, B., Onaral, B. (2012) Using brain activity to predict task performance and operator efficiency, International Conference on Brain Inspired Cognitive Systems, July 11-14, 2012, Shenyang, China. doi: 10.1007/978-3-642-31561-9_16
[ link ]

Ayaz, H., Bunce, S., Shewokis, P. A., Izzetoglu, K., Willems, B., Onaral, B.

Conference Paper

2012

Treatment Status Predicts Differential Prefrontal Cortical Responses to Alcohol and Natural Reinforcer Cues among Alcohol Dependent Individuals

Abstract

This study used functional near-infrared spectroscopy (fNIRs) to test the hypothesis that non-treatment seeking alcohol-dependent participants (NTSA) would show greater response in dorsolateral prefrontal cortex (DLPFC) to alcohol cues than recovering alcoholics (RA; sober 90-180 days) or social drinkers. Opposite predictions were made for responses to natural reward cues. NTSA (n=4), RA (n=6), and social drinkers (n=4) were exposed to alcohol and natural reward cues while being monitored with fNIRs. Results confirmed enhanced responses to alcohol cues among NTSA vs. RA in right middle frontal gyrus. The opposite effect (RA>NTSA) was found in response to natural reward cues. Neural responses to alcohol and natural reward cues were negatively correlated in right DLPFC. Real-time craving ratings were positively correlated with greater neural response to alcohol cues. Differential responses to drug and natural reward cues suggest that a psychological mechanism related to treatment status may modulate drug cue responses in DLPFC.


Citation

Bunce, S., Izzetoglu, K., Izzetoglu, M., Ayaz, H., Pourrezaei, K., Onaral, B. (2012) Treatment Status Predicts Differential Prefrontal Cortical Responses to Alcohol and Natural Reinforcer Cues among Alcohol Dependent Individuals, International Conference on Brain Inspired Cognitive Systems, July 11-14, 2012, Shenyang, China. doi: 10.1007/978-3-642-31561-9_20
[ link ]

Bunce, S., Izzetoglu, K., Izzetoglu, M., Ayaz, H., Pourrezaei, K., Onaral, B.

Conference Paper

2012

Evaluation of UAS Camera Operator Interfaces in a Simulated Task Environment: An Optical Brain Imaging Approach

Abstract

In this paper we focus on the effect of different interface designs on the performance and cognitive workload of sensor operators (SO) during a target detection task in a simulated environment. Functional near-infrared (fNIR) spectroscopy is used to investigate whether there is a relationship between target detection performance across three SO interfaces and brain activation data obtained from the subjects’ prefrontal cortices that are associated with relevant higher-order cognitive functions such as attention, response selection and decision making. The preliminary findings of the study suggest that brain regions in the vicinity of medial frontal gyrus of the right hemisphere respond differentially to the cognitive workload induced by different interfaces.


Citation

Cakir, M. P., Senyigit, A. M., Akay, D. M., Ayaz, H., Isler, V. (2012) Evaluation of UAS Camera Operator Interfaces in a Simulated Task Environment: An Optical Brain Imaging Approach, International Conference on Brain Inspired Cognitive Systems, July 11-14, 2012, Shenyang, China. doi: 10.1007/978-3-642-31561-9_7
[ link ]

Cakir, M. P., Senyigit, A. M., Akay, D. M., Ayaz, H., Isler, V.

Conference Paper

2012

Functional Brain Activity Monitoring during Unmanned Aerial Vehicle Coordination

Abstract

The efficiency and safety of many complex human-machine systems such as Unmanned Aerial Vehicle (UAV) are closely related to the cognitive workload and situational awareness of their operators. Subjective operator reports, physiological and behavioral measures are not reliably sensitive for monitoring cognitive overload. Drexel's Optical Brain Imaging Team has already developed a portable safe and cost-effective optical brain imaging method called functional near-infrared spectroscopy (fNIR) for monitoring the prefrontal cortex in clinical and field settings. The current study examined the relationship of the hemodynamic response in prefrontal cortex to mental workload, level of expertise, and task performance.


Citation

Ayaz, H., Izzetoglu, K., Cakir, M. P., Curtin, A., Harrison, J., Izzetoglu, M., Shewokis, P. A., Onaral, B. (2012) Functional Brain Activity Monitoring during Unmanned Aerial Vehicle Coordination, 20th IEEE Signal Processing and Communications Applications Conference, April 18-20, 2012, Fethiye, Muğla, Turkey. doi: 10.1109/SIU.2012.6204810
[ link ]

Ayaz, H., Izzetoglu, K., Cakir, M. P., Curtin, A., Harrison, J., Izzetoglu, M., Shewokis, P. A., Onaral, B.

Conference Paper

2012

Monitoring Expertise Development during Simulated UAV Piloting Tasks using Optical Brain Imaging

Abstract

An accurate assessment of mental workload and expertise level would help improve operational safety and efficacy of human computer interaction for aerospace applications. The current study utilized functional near-infrared spectroscopy (fNIR) to investigate the relationship of the hemodynamic response in the anterior prefrontal cortex to changes in mental workload, level of expertise, and task performance during learning of simulated unmanned aerial vehicle (UAV) piloting tasks. Results indicated that fNIR measures are correlated to task performance and subjective self-reported measures; and contained additional information that allowed categorizing learning phases. Level of expertise does appear to influence the hemodynamic response in the dorsolateral/ventrolateral prefrontal cortices. Since fNIR allows development of portable and wearable instruments, it has the potential to be deployed in future learning environments to personalize the training regimen and/or assess the effort of human operators in critical multitasking settings.


Citation

Ayaz, H., Cakir, M. P., Izzetoglu, K., Curtin, A., Shewokis, P. A., Bunce, S., Onaral, B. (2012) Monitoring Expertise Development during Simulated UAV Piloting Tasks using Optical Brain Imaging, IEEE Aeroscpace Conference, March 3-10, 2012, BigSky, MN, USA. doi: 10.1109/AERO.2012.6187350
[ link ]

Ayaz, H., Cakir, M. P., Izzetoglu, K., Curtin, A., Shewokis, P. A., Bunce, S., Onaral, B.

Conference Paper

2012

Using functional near infra-red spectroscopy to determine ALS-related motor, cognitive, and language deficits

Abstract

Abstract coming soon...


Citation

Kuruvilla, M. S., Green, J. R., Hogan, T., Yunusova, Y., Ayaz, H. (2012) Using functional near infra-red spectroscopy to determine ALS-related motor, cognitive, and language deficits, Conference on Motor Speech, February 29-March 4, 2012, Santa Rosa, California.
[ ]

Kuruvilla, M. S., Green, J. R., Hogan, T., Yunusova, Y., Ayaz, H.

Conference Paper

2012

Optical Brain Monitoring for Operator Training and Mental Workload Assessment

Abstract

An accurate measure of mental workload in human operators is a critical element of monitoring and adaptive aiding systems that are designed to improve the efficiency and safety of human–machine systems during critical tasks. Functional near infrared (fNIR) spectroscopy is a field-deployable non-invasive optical brain monitoring technology that provides a measure of cerebral hemodynamics within the prefrontal cortex in response to sensory, motor, or cognitive activation. In this paper, we provide evidence from two studies that fNIR can be used in ecologically valid environments to assess the: 1) mental workload of operators performing standardized (n-back) and complex cognitive tasks (air traffic control — ATC), and 2) development of expertise during practice of complex cognitive and visuomotor tasks (piloting unmanned air vehicles — UAV). Results indicate that fNIR measures are sensitive to mental task load and practice level, and provide evidence of the fNIR deployment in the field for its ability to monitor hemodynamic changes that are associated with relative cognitive workload changes of operators. The methods reported here provide guidance for the development of strategic requirements necessary for the design of complex human–machine interface systems and assist with assessments of human operator performance criteria.


Citation

Ayaz, H., Shewokis, P. A., Bunce, S., Izzetoglu, K., Willems, B., Onaral, B. (2012) Optical Brain Monitoring for Operator Training and Mental Workload Assessment, Neuroimage, 59(1), 36-47. doi: 10.1016/j.neuroimage.2011.06.023.
[ link ]

Ayaz, H., Shewokis, P. A., Bunce, S., Izzetoglu, K., Willems, B., Onaral, B.

Journal

2011

Optical Brain Imaging to Enhance UAV Operator Training, Evaluation, and Interface Development

Abstract


Citation

Menda J, Hing JT, Ayaz H, Shewokis PA, Izzetoglu K, Onaral B, Oh P, (2011). Optical Brain Imaging to Enhance UAV Operator Training, Evaluation, and Interface Development. Journal of Intelligent and Robotic Systems, 61:423-443.
[ ]

Menda J, Hing JT, Ayaz H, Shewokis PA, Izzetoglu K, Onaral B, Oh P

Journal

2011

fNIRS Study of Walking and Walking While Talking in Young and Old Individuals

Abstract


Citation

Holtzer R, Mahoney JR, Izzetoglu M, Izzetoglu K, Onaral B, Verghese J, (In Press). fNIRS Study of Walking and Walking While Talking in Young and Old Individuals. Journal of Gerontology
[ ]

Holtzer R, Mahoney JR, Izzetoglu M, Izzetoglu K, Onaral B, Verghese J

Journal

2011

The Evolution of Field Deployable fNIR Spectroscopy From Bench to Clinical Settings

Abstract

In the late 1980s and early 1990s, Dr. Britton Chance and his colleagues, using picosecond-long laser pulses, spearheaded the development of time-resolved spectroscopy techniques in an e®ort to obtain quantitative information about the optical characteristics of the tissue. These e®orts by Chance and colleagues expedited the translation of near-infrared spectroscopy (NIRS)-based techniques into a neuroimaging modality for various cognitive studies. Beginning in the early 2000s, Dr. Britton Chance guided and steered the collaboration with the Optical Brain Imaging team at Drexel University toward the development and application of a ¯eld deployable continuous wave functional near-infrared spectroscopy (fNIR) system as a means to monitor cognitive functions, particularly during attention and working memory tasks as well as for complex tasks such as war games and air tra±c control scenarios performed by healthy volunteers under operational conditions. Further, these collaborative e®orts led to various clinical applications, including traumatic brain injury, depth of anesthesia monitoring, pediatric pain assessment, and brain!computer interface in neurology. In this paper, we introduce how these collaborative studies have made fNIR an excellent candidate for speci¯ed clinical and research applications, including repeated cortical neuroimaging, bedside or home monitoring, the elicitation of a positive e®ect, and protocols requiring ecological validity. This paper represents a token of our gratitude to Dr. Britton Chance for his in°uence and leadership. Through this manuscript we show our appreciation by contributing to his commemoration and through our work we will strive to advance the ¯eld of optical brain imaging and promote his legacy.


Citation

Izzetoglu K, Ayaz H, Merzagora A, Izzetoglu M, Shewokis PA, Bunce SC, Pourrezaei K, Rose A, Onaral B. (2011). The Evolution of Field Deployable fNIR Spectroscopy From Bench to Clinical Settings. Journal of Innovative Optical Health Sciences, 4(3):239-250.
[ link ]

Izzetoglu K, Ayaz H, Merzagora A, Izzetoglu M, Shewokis PA, Bunce SC, Pourrezaei K, Rose A, Onaral B.

Journal

2011

fNIR-based assessment of attention impairments after traumatic brain injury

Abstract

In the late 1980s and early 1990s, Dr. Britton Chance and his colleagues, using picosecond-long laser pulses, spearheaded the development of time-resolved spectroscopy techniques in an e®ort to obtain quantitative information about the optical characteristics of the tissue. These e®orts by Chance and colleagues expedited the translation of near-infrared spectroscopy (NIRS)-based techniques into a neuroimaging modality for various cognitive studies. Beginning in the early 2000s, Dr. Britton Chance guided and steered the collaboration with the Optical Brain Imaging team at Drexel University toward the development and application of a ¯eld deployable continuous wave functional near-infrared spectroscopy (fNIR) system as a means to monitor cognitive functions, particularly during attention and working memory tasks as well as for complex tasks such as war games and air tra±c control scenarios performed by healthy volunteers under operational conditions. Further, these collaborative e®orts led to various clinical applications, including traumatic brain injury, depth of anesthesia monitoring, pediatric pain assessment, and brain!computer interface in neurology. In this paper, we introduce how these collaborative studies have made fNIR an excellent candidate for speci¯ed clinical and research applications, including repeated cortical neuroimaging, bedside or home monitoring, the elicitation of a positive e®ect, and protocols requiring ecological validity. This paper represents a token of our gratitude to Dr. Britton Chance for his in°uence and leadership. Through this manuscript we show our appreciation by contributing to his commemoration and through our work we will strive to advance the ¯eld of optical brain imaging and promote his legacy.


Citation

Merzagora AC, Schultheis MT, Onaral B, Izzetoglu M. (2011). fNIR-based assessment of attention impairments after traumatic brain injury. Journal of Innovative Optical Health Sciences, 4(3):251-260.
[ link ]

Merzagora AC, Schultheis MT, Onaral B, Izzetoglu M.

Journal

2011

Using MazeSuite and functional near infrared spectroscopy to study learning in spatial navigation

Abstract

MazeSuite is a complete toolset to prepare, present and analyze navigational and spatial experiments. Functional near-infrared spectroscopy (fNIR) is an optical brain imaging technique that enables noninvasive and portable monitoring of cerebral blood oxygenation changes. This paper summarizes collective use of MazeSuite and fNIR within a cognitive processing learning paradigm.


Citation

Ayaz H, Shewokis PA, Curtin A, Izzetoglu M, Izzetoglu K, Onaral B. (2011). Using MazeSuite and functional near infrared spectroscopy to study learning in spatial navigation. Journal of Visual Experiments, (56), e3443.
[ link ]

Ayaz H, Shewokis PA, Curtin A, Izzetoglu M, Izzetoglu K, Onaral B.

Journal