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William Freedman

Professor Emeritus

William Freedman

M.S., Mathematics, New York University
Ph.D., Drexel University

Research Interests

Control of motor systems; postural control and locomotion; neural network description of plasticity in motor systems.


Biomechanical and Electromyographic Correlates of Step-down in Humans

The purpose of this project is to determine which sensory parameters dominate the selection of the motor programs for step-down (toe first stepping) or ambulation (heel first stepping). Healthy subjects step from variable heights onto an instrumented walkway. Data are collected on the height of the step-down, the force with which the subject contacts the walkway and muscle activity in order to characterize the motor program selected by the subject.

Postural Sway and its Effects on stability of Stance in the Elderly

The goal of this project is to develop a model of quiet and perturbed stance which will provide the appropriate measures needed to identify people who are incipient "fallers." Measurements of postural sway are performed on an instrumented, movable force plate.

Cervico-ocular Reflex (cor) and Vestibulo-ocular Reflex (vor) Effects on Eye Stability during Passive Movements

The purposes of this project are to determine whether the cor can substitute for a defective vor in stabilizing the eyes during head and body movements. This goal is one milestone in the long range aim of defining the influence of sensory systems on locomotion. The experiments involve testing of humans in a darkened environment during quiet standing on a platform which can be moved in a controlled manner. The subject`s head can be moved separately so that angular perturbations can be applied independently to the head and neck.

Neural Network Description of Plasticity in Motor Dystems

A description of specific motor system plasticity using the framework of non-linear dynamical equations offers the possibility of useful models when considering large neuronal systems.