title: Neuronal activity related to eye-hand coordination in the primate premotor cortex.
abstract: To test the functional implications of gaze signals that we previously reported in the dorsal premotor cortex (PMd), we trained two rhesus monkeys to point to visual targets presented on a touch screen while controlling their gaze orientation. Each monkey had to perform four different tasks. To initiate a trial, the monkey had to put his hand on a starting position at the center of the touch screen and fixate a fixation point. In one task, the animal had to make a reaching movement to a peripheral target randomly presented at one of eight possible locations on a circle while maintaining fixation at the center of this virtual circle (central fixation + reaching). In the second task, the monkey maintained fixation at the location of the upcoming peripheral target and, later, reached to that location. After a delay, the target was turned on and the monkey made a reaching arm movement (target fixation + reaching). In the third task, the monkey made a saccade to the target without any arm movement (saccade). Finally, in the fourth task, the monkey first made a saccade to the target, then reached to it after a delay (saccade + reaching). This design allowed us to examine the contribution of the oculomotor context to arm-related neuronal activity in PMd. We analyzed the effects of the task type on neuronal activity and found that many cells showed a task effect during the signal (26/60; 43%), set (16/49; 33%) and/or movement (15/54; 28%) epochs, depending on the oculomotor history. These findings, together with previously published data, suggest that PMd codes limb-movement direction in a gaze-dependent manner and may, thus, play an important role in the brain mechanisms of eye-hand coordination during visually guided reaching.
authors.affiliation: Institut des Sciences Cognitives, CNRS UPR 9075, 67 Boulevard Pinel, F-69675 Bron Cedex, France,
authors.forename: C
authors.initials: C
authors.lastname: Jouffrais
authors.forename: D
authors.initials: D
authors.lastname: Boussaoud
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D005133:Eye Movements / Q000502:physiology*; D005403:Fixation, Ocular / Q000502:physiology; D006225:Hand / Q000294:innervation*; D008253:Macaca mulatta; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012438:Saccades / Q000502:physiology