Some features of Transcranial Direct Current Stimulation (tDCS) are stated below:
A. The membrane potential of neurons is modulated by applying a weak electrical current between two electrodes placed on the scalp.
B. Neurons under the anode become depolarized, and neurons under the cathode become hyperpolarized during tDCS.
C. tDCS can disrupt neuronal activity and create a “virtual lesion” via anodal stimulation.
D. Neuronal activity is decreased in regions below the anode and increased in regions below the cathode.
Which one of the following options represents the combination of all correct statements?

Correct option is D

Correct Answer
(d) A and B only
Explanation
tDCS works by applying a weak direct current through scalp electrodes, thereby modulating neuronal membrane potentials, making statement A correct. Anodal stimulation generally depolarizes neurons while cathodal stimulation hyperpolarizes them, validating statement B. Statement C is incorrect because virtual lesions are typically associated with cathodal, not anodal, stimulation. Statement D is incorrect as anodal stimulation increases, rather than decreases, neuronal excitability.
Information Booster
• tDCS alters neuronal excitability without directly triggering action potentials
• Anodal stimulation is usually excitatory, while cathodal stimulation is inhibitory
• Effects of tDCS can persist beyond the stimulation period
• Widely studied in neurorehabilitation and cognitive enhancement
Additional Knowledge
Statement C is incorrect because virtual lesion effects are produced by inhibitory (cathodal) stimulation. Statement D is incorrect since neuronal activity increases under the anode and decreases under the cathode, the opposite of what is stated.