Transcranial alternating current stimulation entrains single-neuron activity in the primate brain

Area of Science:

• Neuroscience
• Neurophysiology
• Noninvasive Brain Stimulation

Background:

• Spike timing is crucial for neural computation and communication.
• Transcranial electrical stimulation (tES) is a noninvasive brain stimulation technique with potential therapeutic applications.
• Skepticism exists regarding tES efficacy due to small electric fields and potential indirect effects.

Purpose of the Study:

• To investigate whether and how tES influences neuronal activity in the human brain.
• To provide a mechanistic understanding of tES effects using a relevant animal model.

Main Methods:

• Applied transcranial electrical stimulation (tES) to alert nonhuman primates.
• Recorded individual neuron firing patterns in targeted brain regions.
• Conducted control experiments to rule out indirect effects like sensory stimulation.

Main Results:

• tES consistently altered the timing of neuronal spiking activity.
• tES did not significantly affect the overall rate of neuronal firing.
• Observed frequency- and location-specific effects, including in deep brain structures.

Conclusions:

• tES, as applied in humans, directly influences individual neuron firing patterns in primates.
• The findings provide a strong mechanistic rationale for the clinical use of tES.
• Results will guide the future development and application of tES techniques.