DEFICIT OF HAND PRESHAPING AFTER MUSCIMOL INJECTION IN MONKEY PARIETAL CORTEX

IN order to assess the functional role of the parietal hand movement r egion, the anterior part of the lateral bank of the intraparietal sulc us (IPS), area AIP, in the visual guidance of hand grasping, we revers ibly inactivated several parts of this area with microinjections of Mu scimol in a monkey trained to grasp objects of different shapes, sizes and orientations. During the local inactivation, some of the skilled patterns of finger movements were disrupted in the contralateral hand, due to the lack of preshaping to adjust the finger posture to the obj ect; however, no major deficits in visual reaching were observed. The results suggest that area AIP plays a crucial role in the visual guida nce of goal-directed hand movements.