Ricerc@Sapienza

Obese subjects can be considered “food addicted”. Since there is growing evidence for the role of deep Transcranial Magnetic Stimulation (dTMS) in reducing craving for different addictions, we proposed high frequency (HF) dTMS as a mean to reduce food craving and body weight. To identify regional location of dTMS stimulation we presently measured the regional brain network centrality (degree centrality, DC), in resting-state fMRI brain patterns, to explore plastic changes associated with HF dTMS in obese patients. We used a data-driven approach and computed the regional DC for each patient before the beginning of the treatment (DCT0) and by the end of the treatment (DCT1). For each voxel in the brain, the DC was calculated as the average of the significant functional connections that each voxel has with the remaining voxels in the brain. Then, we computed the difference between DCT1 and DCT0 (△DC=DCT1-DCT0). Finally, we used an independent samples T-test to test the differences in △DC between HF (n=6) and Sham (n=6) groups. All patients underwent 15 sessions (3 per week for 5 weeks). The HF group, compared with the Sham, showed a greater increase of DC by the end of the 5 week-treatment in a cluster centred in the left superior medial frontal gyrus and encompassing the anterior portion of the supplementary motor area (p<.005, cluster-level FWE corrected). No significant DC increase was found in Sham. These preliminary findings suggest the presence of neurofunctional plastic changes associated with excitatory dTMS over both insulae. Specifically, these results suggest a mechanism through which excitatory dTMS can empower self-control and inhibitory processes to resist the feelings of craving. If confirmed in a larger sample of obese patients the present results constitute the evidence of the mechanism of action of high frequency TMS as novel treatment of obesity.