Some studies have suggested that TMS may modulate atypical interactions between two large-scale neuronal networks, the frontoparietal central executive network (CEN) and the medial prefrontal-medial parietal default mode network (DMN). These two functional networks play important roles in emotion regulation and cognition.
In order to advance our understanding of the underlying antidepressant mechanisms of TMS, Drs. Conor Liston, Marc Dubin, and their colleagues conducted a longitudinal study to test this hypothesis.
The researchers used functional magnetic resonance imaging in 17 currently depressed patients to measure connectivity in the CEN and DMN networks both before and after a 25-day course of TMS. They also compared the connectivity in the depressed patients with a group of 35 healthy volunteers.
TMS normalized depression-related hyperconnectivity between the subgenual cingulate and medial prefrontal areas of the DMN, but did not alter connectivity in the CEN.