The role of ventral premotor cortex in eye and head movements

University Of Pittsburgh At Pittsburgh, Pittsburgh PA

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Abstract

ABSTRACT The ventral premotor cortex (PMv) plays a significant role in the control of coordinated movements. Long duration microstimulation of PMv evokes complex orienting and avoidance movements (Cooke & Graziano, 2004; Graziano, Taylor, & Moore, 2002). Such goal directed orienting behaviors often incorporate a movement of the eyes and the head. A recent unpublished anatomical study by Billig and Strick shows that PMv may exert influence over the muscles of the neck and the eye through pathways that do not include other cortical areas (Billig & Strick, 2012). Presence of these pathways and the previously mentioned microstimulation effects strongly suggest that PMv plays a role in gaze shifts. I propose to characterize PMv?s role in coordinating head and eye movements using neural recordings and long duration microstimulation techniques. Rhesus monkeys will be trained to use a head-mounted miniature laser that experimentally controls initial head-in-space position, and consequently eye-in-head rotation, before generation of gaze shifts (Gandhi & Sparks, 2001). The animals will perform goal-directed as well as constant amplitude gaze shifts towards or away from stimuli based on context. Orienting and avoidance behavior will be assessed by comparing gaze shifts toward rewarding objects or away from aversive stimuli. I hypothesize that neural activity encodes both kinematics and the intent of the gaze shift. Goal-directed gaze shifts play a key part in the way we interact with our environment. Full understanding of the neural substrate behind these behaviors will allow us to effectively treat any deficits in gaze shifts that may occur from injuries or disorders.