Sensory Feedback Does Not Cause Selective Adaptation of Human “Command Neurons”

Abstract

It has been proposed that body movements are partly controlled by a neural hierarchy, with cells at successively higher levels controlling increasing numbers of muscles engaged in functionally equivalent responses. In addition to physiological support for the hypothesis, obtained from infrahuman species, evidence from human subjects has been obtained in the form of negative transfer between successive similar responses. This negative transfer has been attributed to selective adaptation of “command neurons” in the human motor system. The present experiment found no evidence for negative (or positive) transfer between passive and active movements, suggesting that selective adaptation of human command neurons is caused by efference rather than afference.