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Projection from low‐threshold muscle afferents of hand and forearm to area 3a of baboon's cortex
Author(s) -
Phillips C. G.,
Powell T. P. S.,
Wiesendanger M.
Publication year - 1971
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1971.sp009579
Subject(s) - anatomy , afferent , baboon , motor cortex , extensor digitorum communis , forearm , chloralose , cortex (anatomy) , central sulcus , neuroscience , chemistry , medicine , biology , stimulation , tendon
1. The precentral and postcentral banks of the Rolandic fissure of the arm area of the baboon's cortex have been probed to their depths with extracellular micro‐electrodes under nitrous oxide and oxygen anaesthesia, supplemented by minimal intravenous pentobarbitone or chloralose. 2. Afferent volleys were sent in from the deep (motor) radial nerve and the deep palmar (motor) branch of the ulnar nerve. Their entry into the central nervous system was timed at the dorsal root entry zone. The nerves were stimulated in continuity and the effects of stimuli below threshold for the motor axons were investigated. 3. Area 3a, in the depths of the postcentral bank, which is cytoarchitectonically transitional between areas 3 and 4, is the receiving area for afferent impulses from muscle. 4. Evoked potential waves and unitary discharges began 4 msec, and the majority of units discharged between 5 and 10 msec, after the afferent volley reached the dorsal root entry zone. 5. Similar responses were elicited by a brief pull (70 μ in 1 msec) or brief vibration (50 μ at 250–400 Hz) applied to the tendons of m. extensor digitorum communis. 6. No potential waves were evoked in area 4, even in the depths adjacent to area 3a, by muscle afferent volleys.