Theta Burst Transcranial Magnetic Stimulation of Fronto-parietal Networks: Modulation by Mental State

The purpose of this study is to improve understanding of the way transcranial magnetic stimulation (TMS), a form of non-invasive brain stimulation, affects the brain. The study hypothesis that when theta burst stimulation (TBS) is applied during a controlled mental state, network changes will be facilitated, compared to stimulation when mental state is uncontrolled. This study will focus on the dorsolateral prefrontal cortex (dlPFC) and the associated frontoparietal network (FPN), which subserves cognitive control - the ability to flexibly adapt and regulate behavior, an ability known to be impaired in neuropsychiatric conditions such as depression and dementia. Healthy volunteers that qualify for this study will have psychological assessments and cognitive measures (due to Covid, some of these were done via teleconference), as well as functional Magnetic Resonance Imaging (fMRI) scans, completed after administration of TMS. Participants will be asked to come in for a total of five visits that include; a screening and assessment visit; a baseline functional magnetic resonance imaging (fMRI) scan, followed by TMS session; Visits 3, 4, and 5 will be the experimental TMS session, followed by fMRI scan.