1. Department of Physiology, Tohoku University School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan
2. The Core Research for Evolutional Science and Technology Program, Kawaguchi, 332-0012 , Japan

Correspondence to: Jun Tanji^1,2 Correspondence and requests for materials should be addressed to J.T. (e-mail: Email: tanjij@mail.cc.tohoku.ac.jp).

Abstract

To plan an action, we must first select an object to act on and the body part (or parts) to use to accomplish our intention. To plan the motor task of reaching, we specify both the target to reach for and the arm to use. In the process of planning and preparing a motor task, information about the motor target and the arm to use must be integrated before a motor program can be formulated to generate the appropriate limb movement. One of the structures in the brain that is probably involved in integrating these two sets of information is the premotor area in the cerebral cortex of primates^{1, 2, 3, 4, 5}. The lateral sector of the dorsal premotor cortex is known to receive both visual and somatosensory input^{6, 7, 8}, and we show here that neurons in this area gather information about both the target and the body part, while subsequent activity specifies the planned action.