rTMS Suppresses Tobacco Craving via Enhanced Prefronto-Striato-Thalamic Connectivity

Studies have used repetitive transcranial magnetic stimulation (rTMS) to stimulate the left dorsolateral prefrontal cortex (DLPFC) in patients with tobacco use disorder (TUD); consequently, decreased craving for smoking was observed. However, the neural mechanism underlying this process remains unclear. Functional MRI data were collected from 59 valid TUD participants (31 rTMS and 28 shams) when they performed a Go/No-go task before and after a continuous 5-day treatment (rTMS on the left DLPFC). Three approaches of data analyses were performed: event-related data analyses to identify the brain regions that are associated with rTMS treatment; functional connectivity (FC) analyses among the left DLPFC (the stimulate region) and other survived brain regions after group comparison; FC between the left DLPFC and all brain regions to find couplings among the brain regions. rTMS decreased the craving for smoking in patients with TUD. Comparing with the sham group, the rTMS group showed enhanced brain responses in the bilateral ACC, bilateral caudate and left thalamus to the No-go smoking cues. Further, FC analyses among the survived brain regions showed that rTMS enhanced the FC in DLPFC-caudate and caudate-left thalamus pathways. Notably, enhanced FC between the DLPFC and bilateral basal ganglia thalamus was observed. The current study demonstrated the effectiveness of rTMS in the treatment of TUD, which is associated with enhanced brain responses that are responsible for executive control and reward processing; it enhanced top-down control by reshaping the prefrontal-striatal pathways.