Modulating somatosensory alpha oscillations using short-period transcranial alternating current stimulation.

Area of Science:

• Neuroscience
• Brain Stimulation
• Electrophysiology

Background:

• Transcranial alternating current stimulation (tACS) modulates neuronal oscillations.
• Longer tACS durations (10-40 min) show persistent changes, particularly in alpha power.
• The efficacy of short tACS durations (1-8 s) remains less understood.

Purpose of the Study:

• To investigate if short tACS periods applied to the somatosensory cortex induce post-stimulation alpha power changes.
• To compare the effects of 10s and 30s tACS trains on neuronal oscillations.

Main Methods:

• Simultaneous magnetoencephalography (MEG) and tACS acquisition.
• Application of 10s and 30s tACS trains at individually adapted stimulation frequency (ISF) followed by a 15s interval.
• Statistical comparison of post-stimulation power changes (Δpower) between tACS and control conditions.

Main Results:

• Significant power elevations at ISF were observed following tACS compared to control.
• The effect extended bilaterally over somatosensory and frontal regions.
• Ten-second tACS produced greater power increases at ISF than 30s tACS, with modulations also seen in the beta band.

Conclusions:

• Short-duration tACS (10s) robustly elevates power in the somatosensory cortex at ISF.
• This finding supports the potential utility of brief tACS protocols in future research.
• tACS can modulate brain oscillations even with very short stimulation periods.