Phase-shifted tACS can modulate cortical alpha waves in human subjects

Area of Science:

• Neuroscience
• Biophysics

Background:

• Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique.
• Understanding the precise effects of tACS on neural activity, particularly traveling waves, is crucial for its therapeutic applications.

Purpose of the Study:

• To investigate traveling waves induced by alpha frequency tACS in healthy subjects.
• To analyze the spatial and temporal dynamics of tACS-induced electric fields and brain activity.
• To explore the potential of tACS for modulating cortical interactions and developing personalized treatment protocols.

Main Methods:

• Electroencephalography (EEG) was recorded from 12 healthy subjects during and after phase-shifted tACS.
• Numerical simulations were performed to model the induced electric fields.
• EEG data analysis was compared with simulation results.

Main Results:

• tACS induced a rotating electric field in the brain, as confirmed by numerical simulations.
• Traveling waves were observed during and after stimulation, with aftereffects lasting at least 30 seconds.
• The directionality of induced waves was controllable.

Conclusions:

• tACS can facilitate the propagation of circulating brain waves in a controlled direction.
• The findings suggest tACS can modulate interactions between distant cortical areas.
• This research opens avenues for innovative tACS protocols for neurological disorders.