Fig 1.

A typical force profile during the force-matching task at 15% MVC of I/I task in an ipsilateral matching task. Reference, Relaxation and Matching represent the periods of the reference force production, force relaxation, and the matching force production, respectively. During each trial, the subject was instructed to match a reference force using the same or different fingers within the hand (i.e., the ipsilateral task), or the fingers of the other hand (i.e., the contralateral task). Note that visual feedback was provided during the Reference and Relaxation periods (solid line), but not the Matching period (dash line).