Roles of Proprioceptive Input in the Programming of Arm Trajectories

TLDR

Sensory loss in limbs causes severe movement disorders, and proprioceptive input from skin, muscle, and joint receptors is essential for movement control, yet its precise role remains incompletely understood, as shown by historical deafferentation studies that revealed both impairments and preserved purposeful movement. The authors concluded that movement initiation depends on afferent input and that coordinated movement arises from concatenated reflex responses.

Abstract

It has been known for more than 100 years that loss or impairment of sensation in our limbs may produce severe disorders of movement and that sensory input plays a critical role in controlling movement. Indeed, the skin, muscles, and joints of our limbs are richly innervated by a variety of sensory receptors that convey proprioceptive information to all levels of the nervous system. What role this input plays in movement control has been a question of recurring interest but remains incompletely understood. In 1895, Mott and Sherrington demonstrated that surgical deafferentation of a monkey's limb produces severe disorders of movement and an unwillingness to use the limb in purposeful action. They therefore concluded that movement initiation requires the support of afferent information and proposed that coordinated movement results from the concatenation of reflex responses. Subsequently, however, it was established that deafferentation does not abolish the capacity to make purposeful...