Abstract
Abstract: Evoking muscle responses by electrical vestibular stimulation (EVS) may help to understand the contribution of the vestibular system to postural control. Although paraspinal muscles play a role in postural stability, the vestibulo-muscular coupling of these muscles during walking has rarely been studied. This study aimed to investigate how vestibular signals affect paraspinal muscle activity at different vertebral levels during walking with preferred and narrow step width. Sixteen healthy participants were recruited. Participants walked on a treadmill for 8 min at 78 steps/min and 2.8 km/h, at two different step width, either with or without EVS. Bipolar electromyography was recorded bilaterally from the paraspinal muscles at eight vertebral levels from cervical to lumbar. Coherence, gain, and delay of EVS and EMG responses were determined. Significant EVS-EMG coupling (P < 0.01) was found at ipsilateral and/or contralateral heel strikes. This coupling was mirrored between left and right relative to the midline of the trunk and between the higher and lower vertebral levels, i.e. a peak occurred at ipsilateral heel strike at lower levels, whereas it occurred at contralateral heel strike at higher levels. EVS-EMG coupling only partially coincided with peak muscle activity. EVS-EMG coherence slightly, but not significantly, increased when walking with narrow steps. No significant differences were found in gain and phase between the vertebral levels or step width conditions. In summary, vertebral level specific modulation of paraspinal muscle activity based on vestibular signals might allow a fast, synchronized, and spatially co-ordinated response along the trunk during walking. (Figure presented.). Key points: Mediolateral stabilization of gait requires an estimate of the state of the body, which is affected by vestibular afference. During gait, the heavy trunk segment is controlled by phasic paraspinal muscle activity and in rodents the medial and lateral vestibulospinal tracts activate these muscles. To gain insight in vestibulospinal connections in humans and their role in gait, we recorded paraspinal surface EMG of cervical to lumbar paraspinal muscles, and characterized coherence, gain and delay between EMG and electrical vestibular stimulation, during slow walking. Vestibular stimulation caused phasic, vertebral level specific modulation of paraspinal muscle activity at delays of around 40 ms, which was mirrored between left, lower and right, upper vertebral levels. Our results indicate that vestibular afference causes fast, synchronized, and spatially co-ordinated responses of the paraspinal muscles along the trunk, that simultaneously contribute to stabilizing the centre of mass trajectory and to keeping the head upright.
Original language | English |
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Pages (from-to) | 507-525 |
Number of pages | 19 |
Journal | Journal of Physiology |
Volume | 602 |
Issue number | 3 |
Early online date | 22 Jan 2024 |
DOIs | |
Publication status | Published - 1 Feb 2024 |
Bibliographical note
Publisher Copyright:© 2024 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.
Funding
Y.C.L. was funded by a scholarship (No. 202 108 520 034) from the China Scholarship Council (CSC). S.M.B. was funded by a VIDI grant (no. 016.Vidi.178.014) from the Dutch Organization for Scientific Research (NWO). The authors appreciate all participants for their voluntary participation. The authors gratefully acknowledge Dr Patrick A. Forbes from Erasmus MC for sharing the MATLAB scripts to calculate the coherence and frequency response function. The authors would like to thank Dr Mohammadreza Mahaki for his help in data collection. The authors thank Bert Clairbois and Richard Casius for the technical assistance. Y.C.L. was funded by a scholarship (No. 202 108 520 034) from the China Scholarship Council (CSC). S.M.B. was funded by a VIDI grant (no. 016.Vidi.178.014) from the Dutch Organization for Scientific Research (NWO).
Funders | Funder number |
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Nederlandse Organisatie voor Wetenschappelijk Onderzoek | |
China Scholarship Council |
Keywords
- balance control
- electrical vestibular stimulation
- gait stability
- paraspinal muscles