The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses

The vestibular system provides sensory information regarding linear and angular motion of the head for tasks such as spatial navigation and postural stabilization. In these dynamic environments examination of vestibular signals is experimentally difficult given current techniques. Recently, continuo...

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Main Author: Dakin, Christopher James
Language:English
Published: University of British Columbia 2012
Online Access:http://hdl.handle.net/2429/43284
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spelling ndltd-UBC-oai-circle.library.ubc.ca-2429-432842018-01-05T17:26:06Z The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses Dakin, Christopher James The vestibular system provides sensory information regarding linear and angular motion of the head for tasks such as spatial navigation and postural stabilization. In these dynamic environments examination of vestibular signals is experimentally difficult given current techniques. Recently, continuous stochastic stimuli have shown promise in addressing some limitations in current vestibular probes and might provide a useful tool for investigating the dynamic behaviour of the vestibular system. The purpose of this thesis is a) to develop further the stochastic stimulus format by examining the customizability of the stimulus bandwidth and the stimulus’ effectiveness in extracting dynamic responses, and b) to use these advancements to explore dynamic vestibular function during locomotion and head rotation. Exploration of the customizability of stimulus bandwidth revealed that a single broad bandwidth stimulus provides similar information to the sum of a series of sinusoidal stimuli or narrow bandwidth stimuli, but in much less time, and that stimulus bandwidth can be modified, by removing frequencies below 2 Hz, to attenuate the postural perturbation created by the stimulus. In a dynamic context the stochastic stimulus was also shown to be very effective in extracting the time varying modulation of vestibular-evoked responses during motion by identifying phase-dependent vestibular responses in the gastrocnemius during locomotion. The stochastic stimulus was then used to examine vestibular modulation and suppression during locomotion and vestibular spatial transformation during head turn. During locomotion, phase-dependent modulation of vestibular responses was observed in muscles of the leg and hip. In some muscles around the ankles these responses are attenuated with increasing cadence and walking speed. Lastly the transmission and spatial transformation of these vestibular-evoked responses are not hindered by motion and the spatial transformation occurs in nearly real time during head rotation. In general, the stochastic stimulus can be customized to reduce postural sway and is effective in extracting the dynamic modulation of vestibular influence on muscle activation. The identification of widespread phase-dependent vestibular coupling in the lower limbs and continuous spatial transformation of vestibular signals demonstrates that the stochastic waveform is an effective tool for the investigation of human vestibular physiology in dynamic contexts. Education, Faculty of Kinesiology, School of Graduate 2012-09-27T22:13:57Z 2012-09-27T22:13:57Z 2012 2012-11 Text Thesis/Dissertation http://hdl.handle.net/2429/43284 eng Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ University of British Columbia
collection NDLTD
language English
sources NDLTD
description The vestibular system provides sensory information regarding linear and angular motion of the head for tasks such as spatial navigation and postural stabilization. In these dynamic environments examination of vestibular signals is experimentally difficult given current techniques. Recently, continuous stochastic stimuli have shown promise in addressing some limitations in current vestibular probes and might provide a useful tool for investigating the dynamic behaviour of the vestibular system. The purpose of this thesis is a) to develop further the stochastic stimulus format by examining the customizability of the stimulus bandwidth and the stimulus’ effectiveness in extracting dynamic responses, and b) to use these advancements to explore dynamic vestibular function during locomotion and head rotation. Exploration of the customizability of stimulus bandwidth revealed that a single broad bandwidth stimulus provides similar information to the sum of a series of sinusoidal stimuli or narrow bandwidth stimuli, but in much less time, and that stimulus bandwidth can be modified, by removing frequencies below 2 Hz, to attenuate the postural perturbation created by the stimulus. In a dynamic context the stochastic stimulus was also shown to be very effective in extracting the time varying modulation of vestibular-evoked responses during motion by identifying phase-dependent vestibular responses in the gastrocnemius during locomotion. The stochastic stimulus was then used to examine vestibular modulation and suppression during locomotion and vestibular spatial transformation during head turn. During locomotion, phase-dependent modulation of vestibular responses was observed in muscles of the leg and hip. In some muscles around the ankles these responses are attenuated with increasing cadence and walking speed. Lastly the transmission and spatial transformation of these vestibular-evoked responses are not hindered by motion and the spatial transformation occurs in nearly real time during head rotation. In general, the stochastic stimulus can be customized to reduce postural sway and is effective in extracting the dynamic modulation of vestibular influence on muscle activation. The identification of widespread phase-dependent vestibular coupling in the lower limbs and continuous spatial transformation of vestibular signals demonstrates that the stochastic waveform is an effective tool for the investigation of human vestibular physiology in dynamic contexts. === Education, Faculty of === Kinesiology, School of === Graduate
author Dakin, Christopher James
spellingShingle Dakin, Christopher James
The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
author_facet Dakin, Christopher James
author_sort Dakin, Christopher James
title The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
title_short The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
title_full The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
title_fullStr The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
title_full_unstemmed The development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
title_sort development of stochastic vestibular stimulation and its application to dynamic vestibular evoked responses
publisher University of British Columbia
publishDate 2012
url http://hdl.handle.net/2429/43284
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