Proprioceptive input resets central locomotor rhythm in the spinal cat

B. A. Conway, H. Hultborn, O. Kiehn

Research output: Contribution to journalArticle

319 Citations (Scopus)

Abstract

The reflex regulation of stepping is an important factor in adapting the step cycle to changes in the environment. The present experiments have examined the influence of muscle proprioceptors on centrally generated rhythmic locomotor activity in decerebrate unanesthetized cats with a spinal transection at Th12. Fictive locomotion, recorded as alternating activity in hindlimb flexor and extensor nerves, was induced by administration of nialamide (a monoamine oxidase inhibitor) and L-DOPA. Brief electrical stimulation of group I afferents from knee and ankle extensors were effective in resetting fictive locomotion in a coordinated fashion. An extensor group I volley delivered during a flexor burst would abruptly terminate the flexor activity and initiate an extensor burst. The same stimulus given during an extensor burst prolonged the extensor activity while delaying the appearance of the following flexor burst. Intracellular recordings from motoneurones revealed that these actions were mediated at premotoneuronal levels resulting from a distribution of inhibition to centres generating flexor bursts and excitation of centres generating extensor bursts. These results indicate that extensor group I afferents have access to central rhythm generators and suggest that this may be of importance in the reflex regulation of stepping. Experiments utilizing natural stimulation of muscle receptors demonstrate that the group I input to the rhythm generators arises mainly from Golgi tendon organ Ib afferents. Thus an increased load of limb extensors during the stance phase would enhance and prolong extensor activity while simultaneously delaying the transition to the swing phase of the step cycle.

LanguageEnglish
Pages643-656
Number of pages14
JournalExperimental Brain Research
Volume68
Issue number3
DOIs
Publication statusPublished - 30 Nov 1987

Fingerprint

Locomotion
Cats
Reflex
Nialamide
Muscles
Mechanoreceptors
Monoamine Oxidase Inhibitors
Motor Neurons
Hindlimb
Ankle
Electric Stimulation
Knee
Extremities

Keywords

  • entrainment
  • fictive locomotion
  • group I afferents
  • motoneurones
  • resetting
  • spinal cord

Cite this

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Proprioceptive input resets central locomotor rhythm in the spinal cat. / Conway, B. A.; Hultborn, H.; Kiehn, O.

In: Experimental Brain Research, Vol. 68, No. 3, 30.11.1987, p. 643-656.

Research output: Contribution to journalArticle

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