Input from muscle and cutaneous nerves of the hand and forearm to neurones of the precentral gyrus of baboons and monkeys

Abstract

3. Responses to electrical stimulation of the deep (motor) radial nerve, the deep palmar (motor) branch of the ulnar nerve, and the superficial (cutaneous) radial nerve could be recorded in the majority of neurones of the motor cortex provided that short trains of strong stimuli were used.Minimal responses to muscle nerve stimulation were observed in a few neurones at 1P4 x group I threshold, but most units reacted only with higher stimulus intensities (2-3 x group I threshold).4. The latencies to peripheral nerve stimulation were measured from the first peak of the incoming volley recorded at the root entry zone. The mean response latencies of pyramidal tract cells were between 20 and 25 msec; non-pyramidal tract cells were activated at slightly shorter mean latencies, the difference being significant for superficial radial nerve stimulation only (4 msec). These latencies are more than twice as long as those recorded in the postcentral gyrus, and the probability of discharge is lower than for postcentral neurones. 5. A further difference between neurones of the postcentral and precentral gyrus is the pronounced convergence from different nerves and also from different modalities (cutaneous and muscle afferents) in units of the precentral cortex in contrast to units of the postcentral cortex.

Functional properties of monkey motor cortex neurones receiving afferent input from the hand and fingers

“…Since most of the cutaneous neurones were not influenced by joint motion it would appear that modality of afferent input from the hand remains separate within the motor cortex. However 12 % of the present sample showed convergent responses to both cutaneous and joint motion stimuli, as reported previously (Wiesendanger, 1973;Wong et al 1978).…”

Electromagnetic Muscle Stretch Strongly Excites Sensorimotor Cortex Neurons in Behaving Primates

“…The data are in accord with results in acute anesthetized preparations (8,9) and awake relaxed animals (6) indicating that short-latency responses to muscle stretch occur in primary motor as well as primary sensory cortex. The predominance of phasic responses and the small magnitude of FCU stretch (< 75 Am in the cadaver) suggest that group IA muscle afferents play a significant role.…”

Somatosensory and motor representations in cerebral cortex of a primitive mammal (Monodelphis domestica): A window into the early evolution of sensorimotor cortex

“…Similarly, Malis et al (1953) found that sensory-evoked potentials could be elicited in precentral motor cortex in monkeys. More recent electrophysiological studies have confirmed somatic motor functions in S1 (Doetsch and Gardner, 1972;Sapienza et al, 1981;Gioanni and Lamarche, 1985) and somatic sensory functions in M1 (Welt et al, 1967;Thompson et al, 1970;Rosén and Asanuma, 1972;Wiesendanger, 1973;Asanuma et al, 1979Asanuma et al, , 1980Tanji and Wise, 1981;Strick and Preston, 1982;Asanuma and Arissian, 1984;Nudo et al, 1997).…”