Physiology of Transcranial Direct Current Stimulation

Area of Science:

• Neuroscience
• Neuromodulation
• Brain Stimulation

Background:

• Noninvasive brain stimulation techniques have evolved significantly since the 1950s.
• Transcranial direct current stimulation (tDCS) alters brain activity by modulating neuronal excitability, unlike methods that directly induce activity.
• tDCS induces both acute and long-lasting changes in cortical excitability, mimicking neuroplastic processes like long-term potentiation and depression.

Purpose of the Study:

• To review the current understanding of the physiological mechanisms underlying transcranial direct current stimulation (tDCS).
• To explore the acute, neuroplastic, and network-level effects of tDCS.
• To provide a foundation for the scientifically sound application of tDCS as a therapeutic tool.

Main Methods:

• Literature review of studies investigating the physiological effects of tDCS.
• Analysis of research on acute regional effects, neuroplastic changes, and network impacts.
• Synthesis of current knowledge on tDCS mechanisms of action.

Main Results:

• tDCS modulates spontaneous brain activity and neuronal excitability via subthreshold effects.
• Specific tDCS protocols can induce long-lasting neuroplastic alterations relevant to learning and memory.
• tDCS impacts cerebral networks, influencing overall brain function.

Conclusions:

• While knowledge is incomplete, significant progress has been made in elucidating tDCS physiological mechanisms.
• Understanding these mechanisms is crucial for optimizing tDCS efficacy in clinical settings.
• Further research will continue to refine the application of tDCS for neurological and psychiatric conditions.