DESIGN FEATURES OF THE SEGMENTAL MOTOR CONTROL SYSTEM: THE EFFICACY OF MONOSYNAPTIC SPINDLE IA CONNECTIONS ONTO THEIR HOMONYMOUS MOTONEURONS (EPSP, SPINAL CORD, COMPOSITE, NEUROPHYSIOLOGY).

Persistent Link:
http://hdl.handle.net/10150/187843
Title:
DESIGN FEATURES OF THE SEGMENTAL MOTOR CONTROL SYSTEM: THE EFFICACY OF MONOSYNAPTIC SPINDLE IA CONNECTIONS ONTO THEIR HOMONYMOUS MOTONEURONS (EPSP, SPINAL CORD, COMPOSITE, NEUROPHYSIOLOGY).
Author:
Vanden Noven, Sharyn
Issue Date:
1984
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
In the field of spinal-cord neurophysiology, the nature of and the rules which govern the strength of functional connections between muscle afferents and motoneurons supplying the same muscle are important to delineate. This study addressed a facet of this issue by testing the possibility that the strength of the spindle Ia-motoneuronal connections is stronger (as demonstrated by the differing amplitudes of the mean maximum composite Ia EPSPs) if both neurons supply the same sub-volume of the muscle, providing the various sub-volumes of the muscle are capable of independent action. Intracellular recordings were made of the Ia EPSP responses of semimembranosus (SM) and lateral gastrocnemius (LG) motoneurons in anesthetized low-spinal cats to electrical stimulation (Group I range) of nerve branches supplying different parts of the homonymous muscle, as well as different heteronymous muscles. For study of SM motoneurons, stimulated nerve branches included those supplying the anterior (SMa) and posterior (SMp) heads of the SM muscle and three providing heteronymous input from the anterior (BFa) and posterior (BFp) parts of biceps femoris and the distal part of the semitendinosus (STd) muscle. Ia EPSPs were partitioned such that stimulation of the SMa nerve branch produced significantly larger EPSPs in SMa motoneurons than in SMp cells; likewise, stimulation of the SMp nerve branch produced larger EPSPs in SMp motoneurons than in SMa cells. Study of the differences in the strength of heteronymous Ia input (i.e., from BFa, BFp and STd) between the SMa and SMp cell groups correlates with the different actions reported previously for the two heads of the SM muscle. For study of LG motoneurons, the stimulated nerve branches were those supplying the four neuromuscular compartments of the LG muscle (LG1, LG2, LG3 and LGm) and the nerve to a heteronymous muscle, soleus (SOL). In all five instances, partitioned Ia effects were evident. An association is suggested between the present results and previous electromyographic studies. The previous studies have shown that the muscle heads (SM) or neuromuscular compartments (LG) under consideration in this study are capable of somewhat separate actions. The present study also included assessment of the relative extent to which the partitioned Ia effects could be attributed, in part, to one or two developmental factors, topographic specificity and species specificity. The analysis suggested that both factors were potentially implicated, with species specificity somewhat predominant over topographic specificity.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Spinal nerves.; Neuromuscular spindles.; Neuromuscular transmission.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Physiology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Stuart, Douglas G.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleDESIGN FEATURES OF THE SEGMENTAL MOTOR CONTROL SYSTEM: THE EFFICACY OF MONOSYNAPTIC SPINDLE IA CONNECTIONS ONTO THEIR HOMONYMOUS MOTONEURONS (EPSP, SPINAL CORD, COMPOSITE, NEUROPHYSIOLOGY).en_US
dc.creatorVanden Noven, Sharynen_US
dc.contributor.authorVanden Noven, Sharynen_US
dc.date.issued1984en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractIn the field of spinal-cord neurophysiology, the nature of and the rules which govern the strength of functional connections between muscle afferents and motoneurons supplying the same muscle are important to delineate. This study addressed a facet of this issue by testing the possibility that the strength of the spindle Ia-motoneuronal connections is stronger (as demonstrated by the differing amplitudes of the mean maximum composite Ia EPSPs) if both neurons supply the same sub-volume of the muscle, providing the various sub-volumes of the muscle are capable of independent action. Intracellular recordings were made of the Ia EPSP responses of semimembranosus (SM) and lateral gastrocnemius (LG) motoneurons in anesthetized low-spinal cats to electrical stimulation (Group I range) of nerve branches supplying different parts of the homonymous muscle, as well as different heteronymous muscles. For study of SM motoneurons, stimulated nerve branches included those supplying the anterior (SMa) and posterior (SMp) heads of the SM muscle and three providing heteronymous input from the anterior (BFa) and posterior (BFp) parts of biceps femoris and the distal part of the semitendinosus (STd) muscle. Ia EPSPs were partitioned such that stimulation of the SMa nerve branch produced significantly larger EPSPs in SMa motoneurons than in SMp cells; likewise, stimulation of the SMp nerve branch produced larger EPSPs in SMp motoneurons than in SMa cells. Study of the differences in the strength of heteronymous Ia input (i.e., from BFa, BFp and STd) between the SMa and SMp cell groups correlates with the different actions reported previously for the two heads of the SM muscle. For study of LG motoneurons, the stimulated nerve branches were those supplying the four neuromuscular compartments of the LG muscle (LG1, LG2, LG3 and LGm) and the nerve to a heteronymous muscle, soleus (SOL). In all five instances, partitioned Ia effects were evident. An association is suggested between the present results and previous electromyographic studies. The previous studies have shown that the muscle heads (SM) or neuromuscular compartments (LG) under consideration in this study are capable of somewhat separate actions. The present study also included assessment of the relative extent to which the partitioned Ia effects could be attributed, in part, to one or two developmental factors, topographic specificity and species specificity. The analysis suggested that both factors were potentially implicated, with species specificity somewhat predominant over topographic specificity.en_US
dc.description.noteDigitization note: pg. 65 missing from original paper.en
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectSpinal nerves.en_US
dc.subjectNeuromuscular spindles.en_US
dc.subjectNeuromuscular transmission.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePhysiologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorStuart, Douglas G.en_US
dc.contributor.committeememberAngevine, Jay B., Jr.en_US
dc.contributor.committeememberLansing, Robert W.en_US
dc.contributor.committeememberHasan, Ziaulen_US
dc.contributor.committeememberGore, Robert W.en_US
dc.identifier.proquest8504135en_US
dc.identifier.oclc693404828en_US
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