The Journal of physiology
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The Journal of physiology · Oct 1982
Closely coupled excitation of gamma-motoneurones by group III Muscle afferents with low mechanical threshold in the cat.
1. The reflex responses of gamma-motoneurones to discharges of muscle receptors innervated by Group III axons have been examined in hind-limb muscles of decerebrated and spinal cats.2. Electrical stimulation of the gastrocnemius medialis nerve at a strength sufficient to excite Group III axons caused excitation of gastrocnemius lateralis or soleus gamma-motoneurones. ⋯ Receptive fields of all Group III units were confined to either the proximal third or distal third of gastrocnemius medialis or, in a few instances, the Achilles tendon.11. We conclude that discharges in Group III axons from receptors which respond to non-noxious, low threshold mechanical stimuli cause a tightly coupled excitation of gamma-motoneurones. The likely contribution of this reflex to the control of movement is discussed.