Edward G. Freedman, Ph.D.

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RESEARCH:

Neural Control of Coordinated Movements.

Maintaining our sense of the world around us and being able to interact with our environment depends in large part on the nervous system's ability to perform a few basic functions. We must be able to gather accurate sensory information about our surroundings, distinguish our movements from the movements of objects in the world, and coordinate our own movements in order to orient, and navigate smoothly through a complex setting. Vision, audition and somatosensation provide information about objects in the world, information about self movement is provided through the vestibular and proprioceptive systems. This wealth of sensory information must be integrated into a unified representation of objects including our own bodies. This neural representation of the environment can then be used to plan and implement behaviors which allow us to manipulate and interact with objects of interest. For example, we might hear or see an object in the periphery, and in order to visually localize and identify the object we need to plan and execute a movement which will re-direct our line of sight. To accomplish this task (which we do more than 125,000 times a day) we need to assess the object's location based on either the visual or auditory inputs. Then we must compute the difference between our current line of sight and the position of the target, incorporate information about the capabilities of the body segments which will contribute to moving the line of sight (e.g. the mobility of the eyes and head given their current positions), and coordinate more than 40 muscles and muscle groups to smoothly look at the target. Although we generally take this type of computationally intensive behavior for granted, even minor failures can cause a drastic reduction in our ability to function adequately in the world.

My approach to understanding these critical brain functions focuses on issues of sensori-motor integration and the neural computations necessary to plan and execute coordinated movements. In particular, using psychophysical and neurophysiological techniques, research in my lab addresses the neural mechanisms which result in the control and coordination of visual orienting behaviors.

SELECTED PUBLICATIONS:

Freedman, E.G. Coupling Between Horizontal and Vertical Components of Saccadic Eye Movements during Constant Amplitude and Direction Gaze Shifts in the Rhesus Monkey. J. Neurophysiology. 100:3375-3393, 2008.

Freedman, E.G. Coordination of the Eyes and Head during Visual Orienting Behaviors. Invited Review, Exp. Brain Res.190: 369-387, 2008.

Cecala, A.L., and Freedman, E.G. Amplitude Changes in response to Target Displacements During Human Eye-Head Movements. Vision Res. 48: 149-166, 2008.

Freedman, E.G. and Sparks, D. L. Coordination of the eyes and head: Movement kinematics. Exp. Brain Res.131:22-32, 2000.

Freedman, E. G. Interactions between eye and head control signals can account for movement kinematics. Biological Cybernetics, 84: 453-462, 2001.

Freedman, E.G. and Quessy, S. Electrical stimulation of rhesus monkey nucleus reticularis gigantocellularis: II. Effects on metrics and kinematics of ongoing gaze shifts to visual targets. Exp. Brain Res. 156: 357-376, 2004.

Quessy, S and Freedman, E.G. Electrical stimulation of rhesus monkey nucleus reticularis gigantocellularis: Characteristics of evoked head movements. Exp. Brain Res. 156:342-356, 2004.

Freedman, E.G. and Sparks, D.L. Activity of cells in the deeper layers of the superior colliculus of the rhesus monkey: Evidence for a gaze displacement command. J. Neurophysiol. 78: 1669-1690, 1997.

Freedman, E.G. and Sparks, D.L. Eye-head coordination during head-unrestrained gaze shifts in rhesus monkeys. J. Neurophysiol. 77:2328-2348, 1997.

Current Appointments

• Associate Professor - Department of Neurobiology and Anatomy (SMD)
• Associate Professor - Department of Biomedical Engineering (SMD)

Education
PhD Neuroscience	Univ of Pennsylvania	1996
MS Neurobiology	Cornell University	1992
BS Biology	Brown University	1986

Post-Doctoral Training & Residency
Post-doctoral Fellow, Univ. of Washington, Seattle WA	1997 - 1999
Post-doctoral Fellow, Univ. of Pennsylvania, Philadelphia PA.	1996 - 1997

Lab Website

http://www.urmc.rochester.edu/labs/Freedman-Lab/

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Recent Journal Articles
Showing the 5 most recent journal articles. (26 available)
Cecala AL; Freedman EG. "Head-unrestrained gaze adaptation in the rhesus macaque." Journal of neurophysiology. 2009; 101(1):164-83. Epub 2008 Nov 12.
Freedman, E.G. "Coupling Between Horizontal and Vertical Components of Saccadic Eye Movements during Constant Amplitude and Direction Gaze Shifts in the Rhesus Monkey." J. Neurophysiology 100 (2008): 3375-3393.
Cecala AL; Freedman EG. "Amplitude changes in response to target displacements during human eye-head movements." Vision research. 2008; 48(2):149-66. Epub 2007 Dec 21.
Freedman EG. "Coordination of the eyes and head during visual orienting." Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale. 2008; 190(4):369-87. Epub 2008 Aug 13.
Freedman EG; Cecala AL. "Oblique gaze shifts: head movements reveal new aspects of component coupling." Progress in brain research. 2008; 171():323-30.