Premotor and motor cortex and visually guided grasp - A methodological and experimental study of local field potentials in the cortex of the awake, behaving macaque monkey

When we reach for and grasp an object, we must transport our hand to the correct location, shape it appropriately and subsequently grasp the object with an appropriate amount of force. This involves a complex series of neuronal computations to process the visual properties of the object, generate a desired action, and to finally relay instructions to the musculature of the hand and arm to execute the action. The premotor and primary motor cortices constitute an important part of this pathway. In the macaque monkey, the premotor cortex (F5) is known to receive visual and visuomotor information concerning the properties of graspable objects from the anterior intraparietal region (AIP). A strong reciprocal connection links F5 to the primary motor cortex (M1), from which the major descending output to the hand and arm muscles originates. This thesis is a study of local field potentials recorded in M1 and F5 during the performance of a reach to grasp task in the macaque monkey, and investigates their relationship to the task and to each other during two phases of the task; the observation of the object to be grasped, and the execution of the grasp. This study required the development of sophisticated techniques for the accurate localisation of recordings and for chronic recordings to be made with multiple electrodes in the two different cortical areas simultaneously. The use of MRI to aid localisation, and the use of an antimitotic solution that retards dural growth and thus allows long term multielectrode recordings are also described and validated