Experimental Brain Research

, Volume 12, Issue 2, pp 161–170 | Cite as

Effects of prolonged stretch of flexor muscles upon excitability of an extensor reflex arc

  • M. Decandia
  • E. Eldred
  • F. S. Grover
Article
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Summary

Prolonged steady stretch of flexor muscles inhibits the monosynaptic response evoked by maximal stimulation of Group I extensor afferent fibers. However, the amplitude of the monosynaptic response tends to recover control values as a function of time. No temporal correlation between adaptation of inhibiting receptors and adaptation of inhibition has been found. As a consequence, it seems that the disinhibiting mechanism must be located mainly within the spinal cord. Usually, enhanced excitability of extensor primary afferent endings in monosynaptic contact with homonymous motoneurons occurs as long as the stretch of flexor muscles is maintained, but it dwindles to a relatively steady value, and so paralleling the changes of the monosynaptic responses, with opposite sign.

Key Words

Monosynaptic response Primary afferent depolarization Muscle stretch 
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Copyright information

© Springer-Verlag 1971

Authors and Affiliations

  • M. Decandia
    • 1
  • E. Eldred
    • 1
  • F. S. Grover
    • 1
    • 2
  1. 1.Department of Anatomy and Brain Research InstituteUniversity of California at Los AngelesUSA
  2. 2.Department of PhysiologyUniversity of Southern CaliforniaLos Angeles

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