Increased transcranial magnetic motor threshold after ECT. A case report.

Electroconvulsive therapy (ECT) is a powerful antidepressive treatment, but its mechanism of action remains poorly understood. To clarify the influence of ECT on corticospinal tract excitability we tested the motor threshold, the motor evoked potential (MEP) input/output curve, and the intracortical excitability using transcranial magnetic stimulation in a depressed patient before and after successful treatment with ECT. Resting motor thresholds were increased bilaterally after treatment, and the input/output curve less steep. These results point to a decreased excitability of the corticospinal motor tract after successful ECT.