Abstract: Transcranial direct current stimulation（tDCS）, as a non-invasive brain stimulation technique, is widely used in improving brain function and behavior. Growing evidence shows its broad therapeutic promise in neuropsychiatric disorders.However, there is a lot of uncertainty about how this approach works. This review focuses on the current research on the mechanism of tDCS. The immediate effect of tDCS is mainly reflected in the change of membrane potential of neurons, while the aftereffect of tDCS can cause dynamic changes in Ca2+concentration, regulate the release and distribution of various neurotransmitters, directly or indirectly alter synaptic plasticity, and play an important role in the regulation of synaptic metaplasticity. In addition to regional effects, tDCS results in widespread network-level changes across the brain. This review probes into the predicament of current research and puts forward some unsolved problems.

Key words: transcranial direct current stimulation（tDCS）, mechanism, synaptic plasticity