eprintid: 10098605
rev_number: 8
eprint_status: archive
userid: 695
dir: disk0/10/09/86/05
datestamp: 2020-05-26 17:10:45
lastmod: 2020-05-26 17:10:45
status_changed: 2020-05-26 17:10:45
type: thesis
metadata_visibility: show
creators_name: Beith, Iain David
title: Reflex control of human trunk muscles
ispublished: unpub
keywords: Biological sciences; Muscle control
note: Thesis digitised by ProQuest.
abstract: Muscles of the human trunk are arranged in layers and attach either to the vertebral column or to the pelvis and thorax. Present understanding suggests the deeper muscles, attached to the vertebral column, stabilise the spine, whereas the more superficial muscles, attached to the thorax and pelvis, produce and control trunk movement. If so, the control of these two groups may differ, with deeper muscles working synergistically and those more superficially located acting antagonistically to one another. To this end the role that reflex connections between the different muscles may play in mediating either synergistic or antagonistic roles was investigated. Muscle afferent activity was evoked via a series of mechanical taps applied to individual muscle/tendon complexes of three abdominal and two paraspinal muscles by means of a mechanical tapping device. The resultant reflex responses were recorded by surface electromyography in the same five muscles, both ipsilateral and contralateral to the applied tap. This allowed analysis of the effect of muscle afferents from any one muscle to all the others. Short latency, (less than 25ms) heteronymous muscle afferent connections are excitatory and widespread between the abdominal muscles. They are also excitatory between ipsilateral paraspinal muscles, but inhibitory between these muscles contralaterally. Reflexes are mostly absent between abdominal and paraspinal muscles. Specifically, connections both to and from the internal oblique muscle (IO), the deepest abdominal muscle studied, were the most widespread and potent, with the connection from one IO to the other being of similar amplitude and minimal difference in latency. It is suggested that at least the earliest part of the short latency excitatory crossed reflexes observed here, are monosynaptically mediated. In addition, there is evidence of asymmetry in the presence and strength of these reflexes between the left and right sides. Longer latency reflexes with latencies of between 40 and 50ms were also observed between all muscle groups studied. These were excitatory within the abdominal and paraspinal groups, but inhibitory between them. However, whether these originate from muscle or cutaneous afferents is unclear.
date: 2002
oa_status: green
full_text_type: other
thesis_class: doctoral_open
thesis_award: Ph.D
language: eng
thesis_view: UCL_Thesis
primo: open
primo_central: open_green
verified: verified_manual
full_text_status: public
pages: 258
institution: UCL (University College London)
department: Department of Physiology
thesis_type: Doctoral
citation:        Beith, Iain David;      (2002)    Reflex control of human trunk muscles.                   Doctoral thesis  (Ph.D), UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10098605/1/10014995.pdf