Sonja Cornelsen

People execute a variety of arm and hand movements to interact with objects in the environment. These movements can be performed accurately even in the presence of sudden perturbations such as a change of target location or size. The fast adjustment to a change of the target requires the brain to control the movement continuously. Even though people perceive such actions as a single smooth movement, two simultaneous occurring components are distinguished in motor control research. The first one is the reaching movement or transport component, which adjusts the kinematic hand and arm profile to the location and distance of the target. The second component is the grasping movement or grip component. It orients the hand and regulates the width of grip aperture defined as the distance between the thumb and the index finger to fit the shape and size of the target.

Although only grasping requires the fine-grained processing of the target’s shape, size and orientation, both components comprise the movement of the hand to the target, and follow the same goal. Consequently, the question arises whether grasping and reaching movements might share a common neuronal correlate, or distinct cortical regions might mediate these two components of a movement.

Reaching and grasping movements require the contribution of several parietal and premotor areas. Whereas some of these areas belong to the dorsolateral circuit associated with grasping, others are part of the dorsomedial circuit associated with reaching. The extent of functional separation between the neuronal correlates of these movements is still under debate. Recent findings indicate that the functional overlap between the dorsolateral and dorsomedial networks might be influenced by specific task requirements.

I am interested in the neuronal correlates of regions involved in the on-line control of reach-to-grasp movements and the question whether the neuronal substrates of these cortical regions are functionally segregated or not.