Abstract
Neuroimaging techniques such as positron emission tomography (PET) have been performed to elucidate the mechanism of action of electroconvulsive therapy (ECT). We showed that acute ECT increases the regional cerebral blood flow (CBF) in the brain stem, diencephalon, basal ganglia, and medial temporal lobes. We particularly emphasized the importance of the centrencephalon for seizure generalization. Furthermore, after 10-30 min of acute ECT, decreased CBF in the anterior cingulate cortex and the medial prefrontal cortex and increased CBF in the thalamus were observed. The CBF reduction in the frontal part of the brain may support the anticonvulsant theory of ECT by Sackeim. After a course of ECT sessions, the results of CBF and glucose metabolism were inconsistent, which could be attributed to the different measurement methods and the time elapsed after the last treatment. Recent studies have shown the effects of ECT on neurotransmitters. One study showed a decrease in the dopamine D2 receptor binding in the rostral cingulate gyrus after a course of ECT, which indicates a downregulation of the receptor. Another study showed a reduction in the 5-HT2 receptor binding in large portions of the cerebral cortex. However, their sample sizes were small, and further studies are required.
