The dorsal visual stream, which includes superior and inferior parietal lobules, is strongly involved in object location and in reach-to-grasp actions (Goodale and Milner, 1992). The inferior parietal lobule is known to be involved in representing object properties and grasping actions; the superior parietal lobule in the on-line processing of visual information for the purpose of directing the hand towards objects to be reached and grasped. Area V6A is a visuomotor area of the superior parietal lobule that shows interesting functional properties to this respect. Single V6A cells are modulated by visual as well as arm-reching movements. V6A cells are involved in the neural computations needed to guide the entire act of prehension, from the transport of the hand towards the object in the peripersonal space to the hand orientation to align it with the orientation of the object, and to the hand preshaping to acquire the object. Indeed V6A contains neurons that code the different types of grip used for grasping different objects. According to these findings, reaching and grasping would be processed by the same populations of neurons. More recently, area V6A has been shown to be involved in coding the visual aspects of graspable objects. Object encoding in V6A reflects visual representations for action, useful for motor control in reach-to-grasp. The majority of V6A cells discharged during both object presentation and grip execution, displaying selectivity for either the object or the grip, or for both object and grip.

These findings could shed new light on the way the brain plans and executes visually guided action.