Abstract
In the last decades, several components of the visual control of eye and hand movements have been disentangled by studying single neurons in the brain of awake macaque monkeys. In this presentation, particular attention will be given to the influence of the direction of gaze upon the reaching activity of neurons of the dorsomedial visual stream. We recorded from the caudal part of the medial posterior parietal cortex, finding neurons sensitive to the direction and amplitude of arm reaching actions. The reaching activity of these neurons was influenced by the direction of gaze, some neurons preferring foveal reaching, others peripheral reaching. Manipulations of eye/target positions and of hand position showed that the reaching activity could be in eye-centered, head-centered, or a mixed frame of reference according to the considered neuron. We also found neurons modulated by the visual features of real objects and neurons modulated also by grasping movements, such as wrist orientation and grip formation. So it seems that the entire neural machinery for encoding eye and hand action is hosted in the dorsomedial visual stream. This machinery takes part in the sequence of visuomotor transformations required to encode many aspects of the reach-to-grasp actions.
Meeting abstract presented at VSS 2017