Abstract
Objective. Maintaining upright posture is a complex task governed by the integration of afferent sensorimotor and visual information with compensatory neuromuscular reactions. The objective of the present work was to characterize the visual dependency and functional dynamics of cortical activation during postural control. Approach. Proprioceptic vibratory stimulation of calf muscles at 85 Hz was performed to evoke postural perturbation in open-eye (OE) and closed-eye (CE) experimental trials, with pseudorandom binary stimulation phases divided into four segments of 16 stimuli. 64-channel EEG was recorded at 512 Hz, with perturbation epochs defined using bipolar electrodes placed proximal to each vibrator. Power spectra variation and linearity analysis was performed via fast Fourier transformation into six frequency bands (Δ, 0.5–3.5 Hz; θ, 3.5–7.5 Hz; α, 7.5–12.5 Hz; β, 12.5–30 Hz; γlow, 30–50 Hz; and γhigh, 50–80 Hz). Finally, functional connectivity assessment was explored via network segregation and integration analyses. Main results. Spectra variation showed waveform and vision-dependent activation within cortical regions specific to both postural adaptation and habituation. Generalized spectral variation yielded significant shifts from low to high frequencies in CE adaptation trials, with overall activity suppressed in habituation; OE trials showed the opposite phenomenon, with both adaptation and habituation yielding increases in spectral power. Finally, our analysis of functional dynamics reveals novel cortical networks implicated in postural control using EEG source-space brain networks. In particular, our reported significant increase in local θ connectivity May signify the planning of corrective steps and/or the analysis of falling consequences, while α band network integration results reflect an inhibition of error detection within the cingulate cortex, likely due to habituation. Significance. Our findings principally suggest that specific cortical waveforms are dependent upon the availability of visual feedback, and we furthermore present the first evidence that local and global brain networks undergo characteristic modification during postural control.
Original language | English |
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Article number | 026037 |
Journal | Journal of Neural Engineering |
Volume | 16 |
Issue number | 2 |
Early online date | 12 Feb 2019 |
DOIs | |
Publication status | Published - 13 Mar 2019 |
Bibliographical note
©2019 IOP Publishing Ltd. After the Embargo Period, the full text of the Accepted Manuscript may be made available on the non-commercial repository for anyone with an internet connection to read and download. After the Embargo Period a CC BY-NC-ND 3.0 licence applies to the Accepted Manuscript, in which case it may then only be posted under that CC BY-NC-ND licence provided that all the terms of the licence are adhered to, and any copyright notice and any cover sheet applied by IOP is not deleted or modified.Keywords
- EEG
- Functional connectivity
- Power spectral density
- Proprioceptive stimulation
- Vertical posture