Transcranial Magnetic Stimulation of Prefrontal Cortex Alters Functional Brain Network Architecture: Graph Theoretical Analysis

Transcranial magnetic stimulation (TMS) is increasingly used in basic as well as clinical research. Intermittent theta burst stimulation (iTBS) with high stimulation intensities are typically applied on frontal cortex as therapy for the modulation of functional connectivity of brain in patients with mood disorders. However, there are not yet sufficient understanding of the impacts of this technique on brain neuronal activities. In this study, we aimed to investigate the network reorganization following the offline application of iTBS to prefrontal cortex at two different intensities. The network architecture was analyzed using resting state functional magnetic resonance imaging as well as graph theory analysis. Results show that the offline iTBS, applied to just one node of the brain network, changes the whole organization of the network. Furthermore, the reorganization followed by the stimulation is dependent on the intensity of the applied stimulation. Moreover, our research suggests that the network analysis can bring new insights into the mechanism of transcranial magnetic stimulation, and improves our understanding of its local as well as global effects.