This article describes a series of experiments directed toward the following questions: (1) Do signals from musculotendinous receptors reach consciousness? (2) Does feed-forward information of muscular force and expected extent of voluntary movement exist? To answer these questions data from voluntary compression of springs and strain-gauge have been analysed in healthy young subjects and in patients with unilateral focal lesions of the cerebral hemispheres.
By successive elimination of information from other sources it was possible to verify that receptors in muscles and tendons do signal movement magnitude and muscular tension to the cerebral cortex, and that this information does indeed reach consciousness. There also exists a feed-forward mechanism signalling parameters of voluntary contraction. However, it is unclear whether peripheral, subcortical, or intracortical loops are directly involved. Perception of signals of muscular tension is abolished by lesions of the contralateral cortex near the central sulcus. It is possible that there exist separate cortical projection areas for kinaesthetic signals from muscles and from joints.