Theta-burst transcranial magnetic stimulation induced functional connectivity changes between dorsolateral prefrontal cortex and default-mode-network.

Functional connectivity (FC) is fundamental to brain function and has been implicated in many neuropsychological and neuropsychiatric disorders. It is then of great scientific and clinical interest to find a non-invasive approach to modulate FC. Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulational tool that can affect the target region and remote brain areas. While the distributed effects of TMS are postulated to be through either structural or functional connectivity, an understudied but of great scientific interest question is whether TMS can change the FC between these regions. The purpose of this study was to address this question in normal healthy brain using TMS with continuous theta burst stimulation (cTBS) pulses, which are known to have long-lasting inhibition function. FC was calculated from resting state fMRI before and after real and control (SHAM) stimulation. Compared to SHAM, the repetitive TMS (rTMS) reduces FC between the cTBS target: the left dorsolateral prefrontal cortex (lDLPFC) and brain regions within the default mode network (DMN), proving the effects of rTMS on FC. The reduction of FC might be the results of the inhibitory effects of cTBS rTMS.