Repetitive transcranial magnetic stimulation of the human prefrontal cortex induces dopamine release in the caudate nucleus

Dopamine is implicated in movement, learning, and motivation, and in illnes ses such as Parkinson's disease, schizophrenia, and drug addiction. Little is known about the control of dopamine release in humans, but research in e xperimental animals suggests that the prefrontal cortex plays an important role in regulating the release of dopamine in subcortical structures. Here we used [C-11] raclopride and positron emission tomography to measure chang es in extracellular dopamine concentration in vivo after repetitive transcr anial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex in healthy human subjects. Repetitive TMS of the left dorsolateral prefrontal cortex caused a reduction in [C-11] raclopride binding in the left dorsal c audate nucleus compared with rTMS of the left occipital cortex. There were no changes in binding in the putamen, nucleus accumbens, or right caudate. This shows that rTMS of the prefrontal cortex induces the release of endoge nous dopamine in the ipsilateral caudate nucleus. This finding has implicat ions for the therapeutic and research use of rTMS in neurological and psych iatric disorders.