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Our research studies the sensory-motor transformation performed by brain systems that controls movements to targets in space. Work in progress examines the role played by the cerebellum in integrating visual and vestibular inputs during eye movements to stationary and moving visual targets during body and head movement. In previous work, we examined motor and premotor cortex neurons during arm movements to targets in space. Initial tasks required single direction movements to lighted buttons in spave. In more recent experiments, monkeys viewed a sequence of button positions, retained these positions during a delay period, and then generated appropriate movement sequences to remembered locations; this paradigm examines both the planning and execution of sequences of movements. Experimental analyses look at both the activities of individual neurons and at interactions among simultaneously recorded groups of single neurons. Theoretical analyses attempt to simulate neural responses usingneural network models, and examine how information coded coarsely at theindividual neuron level could more accurately be coded at the level ofpopulations of neurons. |
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| Ronald E. Kettner Res. Associate Professor PhD UC Irvine |
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| r-kettner@northwestern.edu | ||||||
| Ward 5-090 | ||||||
| (312) 503-0456 |
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A biologically realistic network model of the cerebellum produces responses very similar to those observed during complex predictive eye pursuit. |
Firing rates during 2D trajectories (red) are modeled (blue) by the sum of 2D postion and velocity influences. When position and velocity influences are perpendicular complex responses occur including CCW-specific responses. |
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| Selected Publications: Suh M, Leung H, Kettner RE. (2000) Cerebellar flocculus and ventral paraflocculus purkinje cell activity during predictive and visually driven pursuit in monkey. J. Neurophysiol. 84:1835-1850. Leung HC, Suh M, Kettner RE. (2000) Cerebellar flocculus and paraflocculus Purkinje cell activity during circular pursuit in monkey. J. Neurophysiol. 83:13-30. Leung, H.-C. and Kettner, R. E. (1997) Predictive smooth pursuit of complex two-dimensional trajectories demonstrated by perturbation responses in monkeys. Vis. Res. 37: 1347-1354. Kettner, R.E., Mahamud, S., Leung, H.-C., Sitkoff, N., Houk, J.C. and Peterson, B.W., Barto, A.G. (1997) Prediction of complex two-dimensional trajectories by the eye and by a cerebellar model of smooth eye movement. J. Neurophysiol. 77: 2115-2130. Kettner, R.E., Marcario, J.K., and Clark-Phelps, M.C. (1996) Control of remembered reaching sequences in monkey. I. Activity during movement in motor and premotor cortex. Exp. Brain Res. 112: 335-346. Kettner, R.E., Marcario, J.K., and Port, N. L. (1996) Control of remembered reaching sequences in monkey. II. Storage and preparation before movement in motor and premotor cortex. Exp. Brain Res. 112: 347-358. Kettner, R.E., Leung, H.-C. and Peterson, B.W. (1996) Predictive smooth pursuit of complex two-dimensional trajectories in monkey: component interactions. Exp. Brain Res. 108: 221-235. Georgopoulos, A.P., Schwartz, A. B. and Kettner, R.E. (1986) Neuronal population coding of movement direction. Science 233: 1416-1419.
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