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Updated: Aug 1, 2026

Non-Invasive Electrical Brain Stimulation Montages for Modulation of Human Motor Function
Published on: February 4, 2016
Frequency-specific modulation of motor cortical excitability by transcranial alternating current stimulation
Lei Tingting1,2, Chen Lilin1,3, Wang Chuangjia1
1Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510630, Guangdong, China.
Background:
Transcranial alternating current stimulation (tACS) is a non-invasive technique that modulates neural oscillations, yet its specific effects on cortical excitability are not well-understood. This study investigated the effects of tACS on neuroplasticity in the primary motor cortex (M1) across different frequencies.
Methods:
In this randomized, sham-controlled, crossover study, 18 healthy young adults received β-tACS γ-tACS, and sham stimulation over the M1. Neurophysiological responses were assessed using motor evoked potentials (MEPs), electroencephalograms (EEG), and transcranial evoked potentials (TEPs) to determine the frequency-specific effects of tACS on cortical excitability and neuroplasticity.
Results:
γ-tACS significantly enhanced cortical excitability, as reflected by larger MEP amplitudes compared to both β-tACS and sham stimulation. In addition, γ-tACS resulted in significantly smaller M1-P15 amplitudes in TEP than other stimulation conditions. In contrast, β-tACS did not produce significant changes in either MEPs or TEPs compared to sham stimulation.
Conclusion:
These findings provide evidence that tACS induces frequency-dependent effects on cortical excitability and neuroplasticity within the M1. This selective modulation of cortical excitability with γ-tACS suggests its potential as a therapeutic intervention for optimizing motor function and rehabilitation.
Trial Registration:
This study was registered in the Chinese Clinical Trial Registry (ChiCTR2300074898, date of registration: 2023/08/18).
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