Assessing Cerebral Blood Flow Dynamics associated with TMS Neuromodulation using Arterial Spin Labeling

Motivation: Transcranial magnetic stimulation (TMS) is increasingly used for targeted therapeutic alteration of brain activity. However, the mechanisms underlying these effects are insufficiently understood. Goal(s): This study aims to assess whether TMS neuromodulation affects cerebral blood flow as a mediator of neuromodulation effects. Approach: We conducted arterial spin labeling imaging before and after a TMS neuromodulation experiment including two verum and one sham neuromodulation protocol in 10 healthy volunteers. We used multivariate mixed effects modeling to analyze local CBF dynamics at the stimulation site under the employed TMS conditions. Results: We found no significant dynamics of CBF before- and after TMS. Impact: These initial results suggest that both neuromodulation protocols, as well as TMS stimulation in general does not cause significant local changes in CBF. Other imaging parameters may be more suited to track neuromodulation effects