Cortical Pathways During Postural Control: New Insights From Functional EEG Source Connectivity

Abstract

Postural control is a complex feedback system that relies on vast array of sensory inputs in order to maintain a stable upright stance. The brain cortex plays a crucial role in the processing of this information and in the elaboration of a successful adaptive strategy to external stimulation preventing loss of balance and falls. In the present work, the participants postural control system was challenged by disrupting the upright stance via a mechanical skeletal muscle vibration applied to the calves. The EEG source connectivity method was used to investigate the cortical response to the external stimulation and highlight the brain network primarily involved in highlevel coordination of the postural control system. The cortical network reconfiguration was assessed during two experimental conditions of eyes open and eyes closed and the network flexibility (i.e. its dynamic reconfiguration over time) was correlated with the sample entropy of the stabilogram sway. The results highlight two different cortical strategies in the alpha band: the predominance of frontal lobe connections during open eyes and the strengthening of temporal-parietal network connections in the absence of visual cues. Furthermore, a high correlation emerges between the flexibility in the regions surrounding the right temporo-parietal junction and the sample entropy of the CoP sway, suggesting their centrality in the postural control system. These results open the possibility to employ network-based flexibility metrics as markers of a healthy postural control system, with implications in the diagnosis and treatment of postural impairing diseases.

Sensorimotor recalibration of postural control strategies occurs after whole body vibration

“…The EEG signals were de-trended, mirrored to avoid edge-artefacts, filtered in beta band (13–32 Hz) with a zero-phase FIR filter, cropped and de-trended again. Eye-blinks were removed automatically by subtracting the signals recorded at FP1, FPz and FP2 sites from the remaining 60 EEG channel data, proportionally to their contribution to each channel 66 , 67 . Channels with standard deviation (SD) exceeding the average SD by a factor of 1.7 were replaced by the average of the signals from neighbouring channels 10 .…”

Motion sickness susceptibility and visually induced motion sickness as diagnostic signs in Parkinson’s disease

“…Further studies on MS with BioVRSea on electroencephalographic responses can be interesting to, as in healthy subject, for example to investigate if HC or PD can adapt to this perturbation, as HC know a cortical adaptation during a proprioceptive perturbation, 55,56 and investigate the effect of vision on this adaptation. 57 Concerning the relation between MS and medication, LED did not predict RIMS susceptibility. As discussed above, RIMS susceptibility does not seem to be more frequent in PD patients than in HC.…”

“…Further studies on MS with BioVRSea on electroencephalographic responses can be interesting to, as in healthy subject, for example to investigate if HC or PD can adapt to this perturbation, as HC know a cortical adaptation during a proprioceptive perturbation, 55 , 56 and investigate the effect of vision on this adaptation. 57 …”

EEG Dynamics of Locomotion and Balancing: Solution to Neuro-Rehabilitation

“…Challenging the postural control system by disrupting the upright stance with mechanical skeletal muscle vibrations applied to the calve muscles, the predominance of frontal lobe connections and the strengthening of temporal-parietal network connections were found in the alpha band. 70 Moreover, the auditory biofeedback was applied to the subjects during quiet standing, both with closed and open eyes, suggesting that the postural sway reduces and postural stability increases with auditory biofeedback. 71 On the other hand, the continuous balance tasks of increasing difficulties show that the spectral power of alpha-band reduces as the task difficulty is increased.…”

“…Challenging the postural control system by disrupting the upright stance with mechanical skeletal muscle vibrations applied to the calve muscles, the predominance of frontal lobe connections and the strengthening of temporal-parietal network connections were found in the alpha band. 70…”