2012 Volume 23 Issue 2 Pages 137-142
Positron emission tomography (PET) has been used to elucidate the mechanism of action of electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS). We measured cerebral blood flow during acute ECT and demonstrated an increase in the midbrain, mesencephalon, basal ganglia, etc, suggesting the importance of the centroencephalic areas for seizure generalization and the therapeutic efficacy of ECT. Ten-30 minutes after the seizure, reduction in the medial prefrontal and anterior cingulate and an increase in the thalamus were found, indicating those areas are also important. With the recent development of various radioligands, several researches on the neurotransmission using PET have been reported. One study showed no change in serotonin 1A receptors after a course of ECT, while another showed a decrease in dopamine D2 receptor binding in the anterior cingulate, which indicate down- regulation of the receptor due to dopamine release. Very recently, a widespread reduction in the 5-HT2 receptor bindings in all cortical areas was reported. On the other hand, increases in the release of dopamine by acute TMS have been shown in animal and human studies, however, no change in dopamine D2 receptor binding and dopamine synthesis in the striatum were found after a TMS treatment course for depression.
