+ Site Statistics
References:
52,654,530
Abstracts:
29,560,856
PMIDs:
28,072,755
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn

+ Translate
+ Recently Requested

Organization of recurrent inhibition and facilitation in motoneuron pools innervating dorsiflexors of the cat hindlimb



Organization of recurrent inhibition and facilitation in motoneuron pools innervating dorsiflexors of the cat hindlimb



Experimental Brain Research 125(3): 344-352



The incidence of recurrent inhibition and facilitation in motor nuclei innervating the dorsiflexors of the ankle and digits was examined in spinalized, decerebrate cats. Motoneurons innervating the anterior and posterior portions of the tibialis anterior (TAa and TAp, respectively) received strong recurrent inhibition following stimulation of either of the homonymous muscle nerves. Both motoneuron species received substantial recurrent inhibition from the semitendinosus (St), but stimulation of the nerve to the extensor digitorum longus (EDL), an ankle flexor synergist, evoked smaller recurrent IPSPs. TA motoneurons received mainly facilitation from hindlimb extensors of the hip and ankle. Motoneurons of the EDL and extensor digitorum brevis (EDB), synergists which share mechanical action at the metatarsophalangeal joint and the digits, received little recurrent inhibition in response to stimulation of the nerve to either muscle. Overall, stimulation of heteronymous flexor nerves (including TAa, TAp, and St) failed to evoke responses in most of the EDB and EDL neurons tested (50-83%), and the amplitude of recurrent inhibitory responses was small. Recurrent facilitation from the extensors was more common in these motor nuclei. Most responses recorded in EDB motoneurons following either flexor or extensor nerve stimulation were recurrent facilitations. The sensitivity of this facilitation in EDB motoneurons to injection of polarizing current and its central latency indicate that it is mediated by a disinhibitory, trisynaptic pathway. Stimulation of the nerve to EDB produced recurrent IPSPs in some flexor motoneurons, but these potentials were infrequent and their amplitude was usually small. Based on a comparison of the distribution of recurrent inhibition to published reports of the activities of TAa, TAp, EDL, and EDB during different forms of locomotion, we conclude that recurrent inhibition is large for motor nuclei that exhibit stereotypical activity, while motor nuclei that are activated independently receive and produce little recurrent inhibition. Despite the absence of recurrent inhibition in some motor nuclei, recurrent circuits may still participate in their control through disinhibitory, facilitatory mechanisms.

(PDF emailed within 0-6 h: $19.90)

Accession: 011098229

Download citation: RISBibTeXText

PMID: 10229025

DOI: 10.1007/s002210050690



Related references

Recurrent inhibition and facilitation in motoneuron pools innervating dorsiflexors of the cat hindlimb. Society for Neuroscience Abstracts 23(1-2): 1043, 1997

Topographical organization of the motoneuron pools innervating the muscles of the pinna in the facial nucleus of the cat. Society for Neuroscience Abstracts 18(1-2): 1194, 1992

Simulation of effects of recurrent inhibition of activity of concurrently active motoneuron pools. Society for Neuroscience Abstracts 19(1-3): 140, 1993

The localization of motoneuron pools innervating wing muscles in the chick. Anatomy and Embryology 166(2): 209-218, 1983

CGRP-like immunoreactivity in normal and axotomized motoneuron pools innervating different hind limb muscles in the rat. Society for Neuroscience Abstracts 19(1-3): 617, 1993

Calcitonin gene-related peptide-like immunoreactivity in motoneuron pools innervating different hind limb muscles in the rat. Experimental Brain Research. 96(2): 291-303, 1993

Quantitative studies of chronic facilitation in human motoneuron pools. American Journal of Physiology 150(2): 229-238, 2011

Use of linear quadratic control theory to predict optimal feedback from proprioceptors onto motoneuron pools of the cat hindlimb. Society for Neuroscience Abstracts 14(1): 64, 1988

Relationship between the arrangement of motoneuron pools in the ventral horn and ramification pattern of the spinal nerve innervating trunk muscles in the cat (Felis domestica). Experimental Neurology 128(2): 290-300, 1994

Relationship between the arrangement of motoneuron pools in the ventral horn and ramification pattern of the spinal nerve innervating trunk muscles in the cat ( dag elis domestica). Experimental Neurology 128(2): 290-300, 1994

Organization of recurrent inhibition and facilitation in motor nuclei innervating ankle muscles of the cat. Journal of Neurophysiology (Bethesda) 79(2): 778-790, 1998

Spatial organization within rat motoneuron pools. Neuroscience Letters 60(3): 325-330, 1985

Organization of forelimb motoneuron pools in two bat species. Acta Anatomica 158(2): 121-129, 1997

Topographical organization of the motoneuron pools that innervate the muscles of the pinna of the cat. Journal of Comparative Neurology 363(4): 600-614, 1995