More information about tDCS

Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulation method that applies a weak, constant electrical current (typically ~1–2 mA) to the brain through electrodes placed on the scalp. The current flows between an anode and a cathode, passing through the scalp, skull, and cerebrospinal fluid to reach the cortical surface. Rather than directly triggering action potentials, the electric field slightly shifts the resting membrane potential of neurons. Anodal stimulation generally causes a small depolarisation of neuronal membranes, making neurons more likely to fire in response to incoming synaptic input, whereas cathodal stimulation tends to hyperpolarise neurons, reducing their likelihood of firing. In this way, tDCS modulates the excitability of cortical networks and influences ongoing neural activity rather than generating activity independently.

Beyond these immediate effects on membrane polarisation, repeated or prolonged tDCS can produce longer-lasting changes in synaptic strength by engaging mechanisms of Neuroplasticity, particularly processes similar to Long-Term Potentiation and Long-Term Depression. These plastic changes are thought to involve alterations in neurotransmitter systems (such as glutamatergic and GABAergic signaling), changes in calcium dynamics, and modulation of NMDA-receptor–dependent synaptic activity. Because of these effects on cortical excitability and plasticity, tDCS is widely used in neuroscience research to study brain function and is being explored as a therapeutic tool for neurological and psychiatric conditions, including depression, stroke rehabilitation, and cognitive training.