Changing Cerebral Blood Flow, Glucose Metabolism, and Dopamine Binding Through Transcranial Magnetic Stimulation: A Systematic Review of Transcranial Magnetic Stimulation-Positron Emission Tomography LiteratureS

Abstract

Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disor-ders. Despite its widespread use, we have an incomplete understanding of the way in which acute and chronic sessions of TMS affect various neural and vascular sys-tems. This systematic review summarizes the state of our knowledge regarding the effects TMS may be having on cerebral blood flow, glucose metabolism, and neurotransmitter release. Forty-five studies were identified. Several key themes emerged: 1) TMS transiently increases cerebral blood flow in the area under the coil; 2) TMS to the prefrontal cortex increases glucose metabolism in the anterior cingulate cortex of patients with depression; and 3) TMS to the motor cortex and prefrontal cortex de- creases dopamine receptor availability in the ipsilat-eral putamen and caudate respectively. There is, however, a paucity of literature regarding the effects TMS may have on other neurotransmitter and neuro-peptide systems of interest, all of which may shed vi-tal light on existing biologic mechanisms and future therapeutic development. Significance Statement——Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disorders. This systematic review summarizes the state of our knowledge regarding the effects TMS on cerebral blood flow, glucose metabo-lism, and neurotransmitter release.