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Experimental Brain Research

, Volume 88, Issue 1, pp 59–66 | Cite as

Electromyographic studies of neck muscles in the intact cat

II. Reflexes evoked by muscle nerve stimulation
  • F. J. R. Richmond
  • G. E. Loeb
Article

Summary

Short-latency reflexes were studied in the neck muscles of four alert cats following electrical stimulation of nerves supplying biventer cervicis (BC), splenius (SP) or rectus capitis posterior (RCP). Reflexes were assessed by comparing levels of EMG activity of muscles before and after each stimulus, as the cats lapped milk, licked their paws or walked on a treadmill. When BC or SP nerves were stimulated at 1.5–4 times threshold (T) for their motor axons, no short-latency heteronymous reflexes could be identified in most neck muscles. However, stimulation of RCP nerves produced inhibitory effects as early as 3–4 ms in the ipsilateral BC, CM, and SP muscles and 6 ms in contralateral BC. At stimulus strengths above 4xT, a more complex pattern of inhibitory or excitatory effects was observed in CM, SP and the intervertebral muscle spinalis dorsi. The reflex effects were attenuated or abolished by partial or complete C1 dorsal rhizotomy (2 cats). Cervicocollic reflex data may need to be reevaluated to consider the possible effects of disinhibition rather than excitation in short-latency reflex pathways.

Key words

Reflexes Electromyography Nuchal afferents Neck muscles Cat 

Muscle abbreviations

BC

biventer cervicis

CM

complexus

OCI

obliquus capitis inferior

RCP

rectus capitis posterior

SP

splenius

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Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • F. J. R. Richmond
    • 1
  • G. E. Loeb
    • 1
  1. 1.Department of Physiology and Bio-Medical Engineering UnitQueen's University at KingstonCanada

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