By Jason Hreha

Glossary

Transcranial Electrical Stimulation

Reviewed by Jason Hreha

Published 1 min read

What is transcranial electrical stimulation?

Transcranial electrical stimulation (tES) uses weak currents delivered through scalp electrodes to influence neural activity. It includes transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), and transcranial random noise stimulation (tRNS).

Methods

  • tDCS applies direct current.
  • tACS uses oscillating current, while tRNS uses a varying noise pattern.

Electrode configuration and stimulation settings affect the current's distribution and the resulting neural effects.

Excitation and inhibition

The familiar claim that anodal stimulation excites and cathodal stimulation inhibits comes mainly from particular motor-cortex tDCS studies. It does not reliably predict cognitive outcomes across tasks and brain regions. Frequency, duration, intensity, and the person's state can matter.

Research applications

Researchers use tES to investigate perception, attention, learning, and memory, including working memory. Sham comparisons and possible sensory or wider network effects matter when interpreting changes in performance.

Clinical treatment and cognitive enhancement

Clinical value must be assessed for a particular method, protocol, and condition.

Reports of better performance on a task also do not establish reliable general cognitive enhancement. Replication, effect size, duration, and safety are separate questions.

Why it matters

Brain stimulation can help investigate brain function. The useful conclusion depends on what was stimulated, how it was measured, and which outcome changed.

Sources and further reading