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Depolarization of Ib afferent axons in the cat spinal cord during homonymous muscle contraction.
Author(s) -
Lafleur J,
Zytnicki D,
HorcholleBossavit G,
Jami L
Publication year - 1992
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.1992.sp018927
Subject(s) - orthodromic , chloralose , afferent , contraction (grammar) , muscle spindle , spinal cord , cats , depolarization , anatomy , muscle contraction , neuroscience , chemistry , medicine , stimulation , biology
1. Intra‐axonal records from the intraspinal course of Ib and Ia afferent fibres innervating the gastrocnemius medialis muscle were obtained in chloralose or Nembutal‐anaesthetized cats during submaximal contractions of the muscle. 2. Afferent fibres in continuity with their muscle of origin were functionally identified by their responses to muscle stretch or contraction. 3. In six out of eight Ib afferents, primary depolarizations (PADs) were recorded during contraction. They were independent of the presence of orthodromic impulses fired by tendon organs. 4. These observations support the assumption that the reduction of Ib autogenetic inhibition in homonymous and synergic motoneurones during GM contractions is due to presynaptic inhibition of transmission in Ib pathways.