CBV mapping reveals regional brain activity changes in rats following longitudinal focal Transcranial Magnetic Stimulation (TMS)

Motivation: TMS has been cleared by FDA for treating various neuropsychiatric disorders, but its mechanisms remain poorly understood. Goal(s): This study aims to: i) create a rat model mimicking longitudinal TMS condition in humans; ii) image brain activity resulting from longitudinal TMS. Approach: Healthy adult rats (N=33) underwent daily single-session high-density theta burst stimulation (hdTBS) with a focal TMS coil for 5 days. Cortical excitability and basal brain activity were probed by measuring motor-evoked potential (MEP) and basal CBV. Results: Compared with the sham condition, hdTBS for 5 days significantly enhanced basal CBV and MEP signal. Impact: This is the first awake rat model that replicates the focality and temporal patterns of TMS conditions in humans, opening a novel platform further investigating TMS-induced neuroplasticity.