<p> Although most muscle spindle investigations have used the cat model and
mvasiVe surgical measurement techniques, several investigators have used
microneurography to record from the Ia and II fibres in humans during tendon vibration.
In these studies the muscle spindle primary (Ia) endings are stimulated using transverse
vibration of the tendon at reflex sub-threshold amplitudes. Others have used low
amplitude vibration and the H-reflex (monosynaptic electrical response) to determine
reflex properties during both agonist and antagonist voluntary contractions. Both of these
methods explore only certain parts of the monosynaptic reflex arc; microneurography
focus on the properties and firing characteristics of the muscle spindles themselves,
whereas the H-reflex response to vibration is a representation of the response of the
spinal cord as well as the muscle spindles. </p> <p> In the past we have developed a PC based instrument that uses Lab VIEW and a
linear servomotor to study tendon reflex properties by recording H-reflexes (or stretch
reflexes for mechanical stimuli) from single tendon taps or electrical stimuli to the
afferent nerve. In this thesis we describe a further development of this system to provide
precise vibrations of the tendon at up to 55 Hz with amplitudes up to 4 mm. The
resultant vibration stretch reflex train is extracted from 2 major background noise
sources, 60 Hz power line noise, and vibration artifact noise, of the EMG recording via
phase coherent subtractive filtering. </p> <p> To demonstrate the versatility and efficacy of this system in studying the
monosynaptic reflex arc, test results from several pilot studies are presented, using the
system to vibrate the human distal flexor carpi radialis tendon: (i) whether stretch
reflexes could be entrained with high frequency vibration, as contrary to H-reflexes, (ii)
whether the responses were affected by low levels of agonist or antagonist contraction, in
agreement with the existing pool of work on the subject using the H-reflex, (iii) whether a
separation of the Ia (primary) and II (secondary) ending pathways is observable as
individual but delayed responses at low vibration frequencies due to different activation
characteristics, and axon diameters, of each ending. Possible physiological mechanisms
that explain the resultant behaviour are also discussed. </p> / Thesis / Master of Applied Science (MASc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22374 |
| Date | 08 1900 |
| Creators | Tsang, Kenneth |
| Contributors | de Bruin, Hubert, Electrical and Computer Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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