title: Neuronal activity in the ventral part of premotor cortex during target-reach movement is modulated by direction of gaze.
abstract: We recorded 200 neurons from the ventral part of the premotor cortex (PMv) and 110 neurons from the primary motor cortex (MI) of a monkey performing a visually cued arm-reaching task with a delay. We compared neuronal activity in the premovement period while the monkey reached the target with the eyes fixating on either a left or right fixation target. Our data demonstrate that about half of the movement-related activity in the PMv was modulated by the direction of gaze. In contrast, a vast majority of the activity of MI neurons and about half of PMv neurons were not influenced by the direction of gaze. We further analyzed the movement-related activity during the reaching movement to targets at the top, bottom, left, and right of each fixation point. The magnitude of activity of neurons showing the gaze-direction selectivity was primarily determined by the position of the reaching target relative to the eye-fixation target, and not by the position of the target relative to the animal's body. These data suggest that a part of the coordinate transformation of the motor command signals concerning the direction of reaching from the retinotopic to body-centered frame of reference may occur at the level of premotor cortex but not in MI.
authors.affiliation: Department of Physiology, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mushiake
authors.forename: Y
authors.initials: Y
authors.lastname: Tanatsugu
authors.forename: J
authors.initials: J
authors.lastname: Tanji
mesh_terms: D000818:Animals; D001132:Arm; D003463:Cues; D005403:Fixation, Ocular / Q000502:physiology*; D008251:Macaca; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*