ABSTRACT
The brain’s own body image is normally expressed in both a cognitive and pragmatic manner. By projecting the indentation patterns impressed upon the skin onto external objects that touch its surface, the tactile sense in the hand serves a cognitive function. Information derived from tactile receptors about an object’s intrinsic properties — its 220size, shape, and surface texture — is used to identify and classify it. However, the hand is not merely a sensor; it is also a skillful motor device that can manipulate objects to achieve a desired goal. A functional body image is essential for planning and executing movements, especially the skilled actions of the hand that distinguish primates from lower species. Cutaneous receptors in both glabrous and hairy skin provide information about the kinematics and posture of the hand, as well as the grip and load forces used during prehension and object manipulation (Edin and Abbs, 1991; Edin and Johansson, 1995; Hulliger et al., 1979; Johansson, 1996; Westling and Johansson, 1987). In order to understand coordinated skilled movements of the hand, we need to examine the central representation and dynamics of the pragmatic functions monitored by the tactile system.
