Investigation of neural networks of emotion regulation with transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (FMRI)

The aim of the study is to investigate the changes in the neural networks of emotion regulation by inhibiting the right dorsolateral prefrontal cortex (dlPFC) with transcranial magnetic stimulation (TMS). For this purpose, the behavioral and neural responses were investigated after TMS during emotional regulation task with functional magnetic resonance imaging (fMRG). Furthermore, the effect of TMS on the connectivity of large-scale networks was examined. In a placebo controlled with-in subject design, 1 Hz active and sham TMS was applied to the right dlPFC of 19 healthy subjects in two sessions. After both sessions, fMRI data was recorded during resting state and approach / avoidance task. Functional activation analyses, psychophysiological interaction analysis and seed-based functional connectivity analyses for the resting state were performed. Findings showed that the reaction time was slower and the activation was higher and lateralized to the right hemisphere during the negative stimuli compared to the positive. An increased activation was observed in the left medial prefrontal cortex after active stimulation compared to sham. The response times were shortened, the error rates decreased after the active stimulation and there were altered connections between a large number of large-scale networks both during resting and during the approach / avoidance task. As a result, TMS to the frontal region affects large-scale networks rather than local, negative stimuli are more salience for healthy individuals and this bias can be reduced with TMS. Findings from this study can be an important step in using TMS in the treatment of mood disorders.