Traveling-wave transcranial alternating current stimulation (twtACS) causally links neural timing to cognitive...

Area of Science:

• Neuroscience
• Cognitive Science
• Brain Stimulation

Background:

• Cortical traveling waves (TWs) are neural oscillation patterns crucial for information transfer between brain regions.
• The directional properties of TWs are thought to influence cognitive functions, but direct causal evidence has been limited.
• Understanding the causal role of TWs is essential for developing targeted neuromodulation strategies.

Purpose of the Study:

• To establish a causal link between externally applied TW-like electric fields and brain dynamics/behavior.
• To introduce and validate a novel noninvasive brain stimulation protocol, traveling-wave transcranial alternating current stimulation (twtACS).
• To investigate the impact of directionally controlled electric fields on neural activity and cognitive performance.

Main Methods:

• Development of twtACS, a noninvasive technique to generate precise, directional electric fields mimicking TWs.
• Validation of twtACS-generated electric field propagation using human intracranial recordings.
• Recording neural spiking activity in monkeys and measuring cognitive performance in humans during twtACS application.

Main Results:

• Neural spiking in monkeys was directionally modulated by twtACS, shifting systematically with the applied field direction.
• Human participants exhibited direction-dependent improvements in cognitive performance when stimulated with twtACS.
• Intracranial recordings confirmed the accurate propagation of the electric field generated by twtACS across the cortical surface.

Conclusions:

• Externally imposed TWs, via twtACS, can causally influence neural activity and cognitive functions.
• twtACS provides a novel method for precisely controlling brain activity patterns.
• This study highlights the potential of twtACS as a neuromodulation tool for cognitive enhancement and understanding brain dynamics.