Brain circuits involved in the control of reaching and grasping

The cortex located along the medial bank of the intraparietal sulcus has a key role in the integration of sensory information for accurate reaching and grasping of objects, being fundamental for our ability to interact with the environment using our arms and hands. Lesions involving this region can result in optic ataxia, a condition in which people (and other primates) make mistakes when trying to reach and grasp objects, despite being able to see them. Moreover, damage or disturbances of neuronal activity in this region lead to other clinically relevant phenomena, such as phantom limbs. Although it is recognised that the medial intraparietal cortex is likely to encompass more than one functional area, it remains one of the least well-characterised parts of the primate brain. For example, physiological studies have proposed the existence of a “parietal reach region” (PRR) in which neurones encode the locations of objects that will be the target of reaching movements. However, the extent of the PRR remains unclear, as is its relationship to various functionally distinct areas that occupy this part of the primate brain. Building on recent successes in unravelling the organisation of primate sensory association areas (Rosa et al. 2009; Bakola et al. 2010; Passarelli et al. 2011), this project will achieve the first integrated view of the neuronal circuitry of the medial intraparietal cortex.