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ORIGINAL RESEARCH article

Front. Neurosci.

Sec. Neuroprosthetics

Volume 19 - 2025 | doi: 10.3389/fnins.2025.1524653

This article is part of the Research TopicStimulation Strategies Targeting Plasticity Mechanisms in Diseased Brain NetworksView all 5 articles

Beta tACS of varying intensities differentially affect resting-state and movement-related sensorimotor power

Provisionally accepted
  • 1Murdoch University, Perth, Australia
  • 2Curtin University, Perth, Western Australia, Australia

The final, formatted version of the article will be published soon.

Individuals who face difficulties with voluntary movement experience considerable challenges in performing everyday tasks, significantly compromising their sense of autonomy. Transcranial alternating current stimulation (tACS) holds promise in modulating sensorimotor beta oscillations, which underscore voluntary movement. However, the exact effect of beta tACS on oscillatory power is still largely elusive. This study aimed to examine the effect of different intensities of beta tACS (20 Hz) on both resting-state and event-related sensorimotor oscillations. Twenty-one healthy young adults (13 female; mean age 24.30 ± 4.84 years) received four separate 20 minute sessions of tACS at different intensities (sham, 0.5 mA, 1.0 mA, or 1.5 mA, peak-to-peak), targeting the left primary motor cortex during rest. Electroencephalography (EEG) was recorded before and after stimulation, during both resting state and a self-paced right index finger button press task. Changes in sensorimotor beta power (13 -30 Hz) were analyzed. For the resting-state, none of the real stimulation intensities induced significant changes in beta power relative to sham. For event-related activity, we observed intensity-dependent changes in bilateral broadband power (4 -90 Hz): during movement preparation, 1.0 mA stimulation increased power; during movement termination, 0.5 mA stimulation decreased power while 1.0 mA and 1.5 mA stimulation induced comparable increases in power. While none of the stimulation intensities induced changes in broadband power during movement execution, 1.0 mA stimulation shifted participants' peak beta frequency toward the tACS frequency. Interestingly, changes in power during movement preparation and execution following 1.0 mA stimulation were negatively associated with participants' pre-tACS peak beta frequency. Together, these findings contribute to our understanding of the sensorimotor response to beta tACS, as well as the effect of stimulation intensity on tACS-induced neuromodulation, which has important implications for research and clinical settings.

Keywords: transcranial alternating current stimulation, Electroencephalography, Neural oscillations, Beta Oscillations, Motor Cortex, motor control, power

Received: 08 Nov 2024; Accepted: 19 May 2025.

Copyright: © 2025 Wansbrough, Marinovic, Fujiyama and Vallence. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Kym Wansbrough, Murdoch University, Perth, Australia
Ann-Maree Vallence, Murdoch University, Perth, Australia

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