Document Detail

Neuronal pathways for spinal reflexes activated by group I and group II muscle afferents in the spinal segment (Co1) innervating the tail in the low spinalized cat.
MedLine Citation:
PMID:  10204766     Owner:  NLM     Status:  MEDLINE    
We studied neuronal pathways for spinal reflexes activated by group-I and group-II muscle afferents in the spinal segments innervating the tail in unanesthetized and spinalized (L1) cats. Experiments were performed on 25 adult cats of both sexes. The effects of stimulating nerves innervating six tail muscles on both sides were recorded from tail motoneurons in the first coccygeal spinal segment (Co1) using glass microelectrodes. Stable recordings were obtained from 150 tail motoneurons. Stimulation of group-1 muscle afferents (stimulus intensity <1.8 T) often produced EPSPs (82/150) after stimulating nerves innervating neighboring tail muscles. Motoneurons innervating the long-tendoned muscles, M. extensor caudae lateralis and M. flexor caudae longus (ECL and FCL), received heteronymous monosynaptic connections from group-I muscle afferents innervating the ipsilateral tail muscles. The motoneurons innervating segmental muscles, M. extensor caudae medialis and M. flexor caudae brevis (ECM and FCB), received heteronymous monosynaptic connections from group-I muscle afferents innervating tail muscles on both sides. The motoneurons innervating tail muscles originated from the Ossa coxae, M. abductor caudae externus and M. abductor caudae internus (ACE and ACI), received monosynaptic connection from group-I muscle afferents innervating most of the tail muscles on both sides. Crossed disynaptic inhibitory pathways activated by primary muscle afferent inputs were observed in ECM, ACE, FCL, and FCB motoneurons. The effects of group-II afferent inputs were not dependent on the kind of motoneuron, and alternative excitatory and inhibitory pathways were not clearly observed in the tail motoneuron pool. It is suggested that variability of the neuronal pathways from group-I and -II muscle afferents to tail motoneurons corresponds to functional relationships among tail muscles, depending on the tail movements.
N Wada; N Shikaki
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Experimental brain research     Volume:  125     ISSN:  0014-4819     ISO Abbreviation:  Exp Brain Res     Publication Date:  1999 Mar 
Date Detail:
Created Date:  1999-06-03     Completed Date:  1999-06-03     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  129-38     Citation Subset:  IM    
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MeSH Terms
Decerebrate State / physiopathology*
Electric Stimulation
Lumbosacral Region
Motor Neurons / physiology
Muscle, Skeletal / innervation*
Neural Pathways / physiopathology*
Neurons, Afferent / physiology*
Reflex / physiology*
Spinal Cord / physiopathology*
Synaptic Transmission / physiology
Tail / innervation*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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