Cortical oscillations and interareal synchronization as a preparatory activity for postural response

Abstract

Neural mechanisms of human standing are expected to be elucidated for preventing fallings. Postural response evoked by sudden external perturbation originates from various areas in the central nervous system. Recent studies have revealed that the corticospinal pathway is one of the key nodes for an appropriate postural response. The corticospinal pathway that mediates the early part of the electromyographic response is modulated with prediction before a perturbation occurs. Temporal prediction explicitly exhibiting an onset timing contributes to enhancing corticospinal excitability. However, how the cortical activities in the sensorimotor area with temporal prediction are processed before the corticospinal pathway enhancement remains unclear. In this study, using electroencephalography, we investigated how temporal prediction affects both neural oscillations and synchronization between sensorimotor and distal areas. Our results revealed that desynchronization of cortical oscillation at αand β-bands was observed in the sensorimotor and parietooccipital areas (Cz, CPz, Pz and POz), and those are nested in the phase at θ-band frequency. Furthermore, a reduction in the interareal phase synchrony in the α-band was induced after the timing cue for the perturbation onset. The phase synchrony at the low frequency can relay the temporal prediction among the distant areas and initiate the modulation of the local cortical activities. Such modulations contribute to the preparation for sensory processing and motor execution that are necessary for optimal responses.

Corticocortical and Corticomuscular Connectivity Dynamics in Standing Posture: Electroencephalography Study

“…We concentrated on the impact of spontaneous posture sway and time transition on connectivity dynamics. Based on the above previous research (Mierau et al 2017;Peterson and Ferris 2019;Fujio et al 2023;Stokkermans et al 2023), we inferred that both connectivity would be facilitated by the increased postural demand. Corticomuscular connectivity strength was measured at a specific phase in the anteroposterior (AP) sway in which the lower-limb muscles respond (Masani et al 2003).…”

“…The global α-band network is linked to higher-order cognitive functions, like attention and response selection, which involve the front-parietal network (Hon et al 2006;Sadaghiani et al 2012). Research suggests that a reduction in α-synchrony, particularly in the central region, occurs during the preparation phase for voluntary arm movement (Lu et al 2011) and postural response (Fujio et al 2023), which may serve to maintain a stable internal state for sensory processing. We assume that the tendency of reduced αconnectivity in ON and WD conditions is led by the higher postural demand and contributes to rapid response.…”

“…Based on the above previous research (Mierau et al . 2017; Peterson and Ferris 2019; Fujio et al . 2023; Stokkermans et al .…”

“…Cortical oscillation is an effective probe for capturing posture-related brain activity. Electroencephalography (EEG) studies have shown that the power spectrum in the specific frequency, δ-, θ-, α-, β-, and γ-bands, can indicate the engagement of cortical drive (Thibault et al 2014;Hulsdunker et al 2015;Mierau et al 2017;Fujio et al 2023;Stokkermans et al 2023). Higher β-and γ-powers appeared over occipital and frontal areas in upright posture compared to lying (Thibault et al 2014), while α-power decreased at electrodes over the sensorimotor area before predictable perturbation (Solis-Escalante et al 2019;Fujio et al 2023).…”

“…Electroencephalography (EEG) studies have shown that the power spectrum in the specific frequency, δ-, θ-, α-, β-, and γ-bands, can indicate the engagement of cortical drive (Thibault et al 2014;Hulsdunker et al 2015;Mierau et al 2017;Fujio et al 2023;Stokkermans et al 2023). Higher β-and γ-powers appeared over occipital and frontal areas in upright posture compared to lying (Thibault et al 2014), while α-power decreased at electrodes over the sensorimotor area before predictable perturbation (Solis-Escalante et al 2019;Fujio et al 2023). In the θ-frequency band, higher θ-power in the frontocentral area indicates error monitoring following the postural perturbation (Hulsdunker et al 2015;Stokkermans et al 2023).…”