SHERRINGTON ADOPTED a philosophical rather than a scientific viewpoint (175) when he wrote, "Since Hume it has been admitted that the perceived results of our volition are the outward ends obtained, and not the inward action of the neuromuscular machinery." Sherrington recorded this view in an analysis of the proprioceptive, or kinesthetic, sense, which he called the muscular sense. In particular he was stating his opposition to the idea, variously attributed to Johannes Muller, Helmholtz, Wundt, and others, that internally generated motor signals might have perceptual consequences. Briefly this idea is that signals, generated within the central nervous system from, or together with, the commands for movements, influence sensory perception either by modifying the processing of incoming sensory information or by irradiating higher sensory areas so as to evoke, in their own right, sensations of various kinds. This notion, to which Sherrington and others before and since were so opposed, is examined here.That one must attribute various aspects of kines-
1415In 1950, however, two important conceptual advances occurred, and the terms corollary discharges (187) and efference copy (84, 86) were introduced. Corollary discharges is the broader term. It arose as a suggestion by Sperry to explain behavioral findings obtained in experiments on fish. He had found that MENTS, p. 14331. X Gaze directed oheod Gaze voluntarily shifted Imposed mov't shifts to left gaze to left Eye s t a t k r y Eye moves Eye moves No command Commond given No command X bluntary attempt to look to lefteye muscles paralysed Eye stationary Command given Target appears Target appears Target appears to Target appears to stationor y stationary move to right move to left FIG. 1. Figure depicts circumstances important in historical development of ideas regarding corollary discharges and visual stability. Diagrams show actual positions of eye, viewed target, and retinal image. What appears to the subject to be happening is stated under each diagram.
