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Behavioral/Systems/Cognitive A Relative Position Code for Saccades in Dorsal Premotor
 

Summary: Behavioral/Systems/Cognitive
A Relative Position Code for Saccades in Dorsal Premotor
Cortex
Bijan Pesaran,1 Matthew J. Nelson,2 and Richard A. Andersen2,3
1Center for Neural Science, New York University, New York, New York 10003, and 2Computation and Neural Systems Program and 3Division of Biology,
California Institute of Technology, Pasadena, California 91125
Spatialcomputationsunderlyingthecoordinationofthehandandeyepresentformidablegeometricchallenges.Onewayforthenervous
system to simplify these computations is to directly encode the relative position of the hand and the center of gaze. Neurons in the dorsal
premotorcortex(PMd),whichiscriticalfortheguidanceofarm-reachingmovements,encodetherelativepositionofthehand,gaze,and
goal of reaching movements. This suggests that PMd can coordinate reaching movements with eye movements. Here, we examine
saccade-related signals in PMd to determine whether they also point to a role for PMd in coordinating visual­motor behavior. We first
compared the activity of a population of PMd neurons with a population of parietal reach region (PRR) neurons. During center-out
reaching and saccade tasks, PMd neurons responded more strongly before saccades than PRR neurons, and PMd contained a larger
proportion of exclusively saccade-tuned cells than PRR. During a saccade relative position-coding task, PMd neurons encoded saccade
targets in a relative position code that depended on the relative position of gaze, the hand, and the goal of a saccadic eye movement. This
relative position code for saccades is similar to the way that PMd neurons encode reach targets. We propose that eye movement and eye
position signals in PMd do not drive eye movements, but rather provide spatial information that links the control of eye and arm
movements to support coordinated visual­motor behavior.
Introduction
Hand­eye coordination allows the fovea to guide skilled man-

  

Source: Andersen, Richard - Division of Biology, California Institute of Technology

 

Collections: Biology and Medicine