The Cerebral Correlates of Reaching

This chapter focuses on the cerebral correlates of reaching. The recent studies of the activity of single cells in various brain regions of behaving primates have provided new insights into the brain mechanisms underlying reaching. The chapter discusses these studies with emphasis on parametric studies of the relations of the neuronal activity to the direction of reaching. Reaching to objects of interest in immediate extrapersonal space is an important motor activity of primates in everyday life. The planning and execution of reaching involves the concurrent or sequential activation of several brain regions such as posterior parietal cortex, premotor cortex, and motor cortex. The study of the role of the various areas in this function is made possible by the advent of a technique that allowed the recording of the activity of single cells in the brain of behaving animals during reaching. This technique is indispensable for the study of neural mechanisms underlying motor aspects of behavior. This combined behavioral-neurophysiological experiment provides a fine-grained direct tool by which the brain mechanisms underlying performance can be studied.