Functional mapping of rat brain activation following rTMS using activity-induced manganese-dependent contrast

Objective: Functional neuroimaging techniques act as the navigator to assess changes in brain activity induced by repetitive transcranial magnetic stimulation (rTMS) in rTMS studies. The aim of this study was to investigate the feasibility of using manganese-enhanced magnetic resonance imaging (MEMRI) to measure the brain activity in rTMS studies. Methods: Eighteen Wistar rats were randomized into three groups (n=6) including a high rTMS group, a low rTMS group and a sham stimulation group (controls). They were given rTMS of 10 Hz, 1 Hz or sham stimulation for 5 hours separately. MEMRI was used to assess the changes of brain activity. Results: Compared with the controls, image intensity was enhanced differently in various brain regions on T1-weighted images after rTMS with different frequencies, higher intensity and wider enhancement occurred in the high frequency rTMS group as compared with that in the low frequency rTMS group. Conclusion: MEMRI can be used to reveal the changes of brain activity in live rats following rTMS. Significance: The current experiment might provide a new functional neuroimaging technique for the study of rTMS.