Dopaminergic potentiation of rTMS-induced motor cortex inhibition.

Background: Experiments in animal models suggest that neuronal plasticity can be enhanced by dopaminergic receptor activation. The present study tested whether stimulation-induced plasticity of human motor cortex after low-frequency repetitive transcranial magnetic stimulation (rTMS) could be potentiated by a single oral dose of the combined D1/D2 receptor agonist pergolide.

Methods: In a randomized, double-blind, placebo-controlled cross-over design, nine healthy young volunteers received .

Half sine, monophasic and biphasic transcranial magnetic stimulation of the human motor cortex.

Objective: To compare half sine transcranial magnetic stimuli (TMS) with conventional monophasic and biphasic stimuli, measuring resting and active motor threshold, motor evoked potential (MEP) input/output curve, MEP latency, and silent period duration.

Methods: We stimulated the dominant hand representation of the motor cortex in 12 healthy subjects utilising two different MagPro stimulators to generate TMS pulses of distinct monophasic, half sine and biphasic shape with anteriorly or posteriorly directed current flow.

Results: The markedly asymmetric monophasic pulse with a posterior current flow in the brain yielded a higher motor threshold, a less steep MEP input/output curve and a longer latency than all other TMS types.