Abstract
Background Repetitive transcranial magnetic stimulation (rTMS) of the supplementary motor area (SMA) has been associated with reduced tic severity in Tourette Syndrome (TS), yet little is known about its impact on functional brain networks. Prior research shows individual differences in functional brain organization, such that rTMS targeting the same anatomical region may engage different networks across patients. The current study generated patient-specific functional network maps to identify the extent to which delivering rTMS over SMA may stimulate different functional networks across TS patients. Methods Anatomical, resting-state, and finger tapping task fMRI data were collected from N = 23 youth (12-21 years) with TS pre-investigational rTMS treatment. Individualized rTMS targets were computationally determined based on task activation and modeled electric field data. We later identified the functional cortical parcel corresponding to each participant’s TMS target coordinates and generated individual whole-brain functional connectivity seed maps for that parcel. Results rTMS coordinates used for intervention fell within 7 previously defined cortical parcels that are part of two functional networks. The targeted parcel was within the ventral attention network for n=8 and within the cingulo-opercular network for n=13. Seed maps confirmed strong functional connectivity between each targeted parcel and its corresponding functional brain network. Conclusions We found variable functional network organization within SMA, such that our TMS targeting approach resulted in selecting coordinates within two different networks. Results highlight the importance of considering individual network topography in TMS target selection for youth with TS. Future research will explore whether differential network engagement impacts clinical outcomes.