Modulating Temporoparietal Junction Mentalizing-Related Activity in Autism Spectrum Disorder Using Transcranial Magnetic Stimulation

All participants will be scheduled for four study sessions that include a baseline and three subsequent sessions that will each include two functional magnetic resonance imaging (fMRI) scans, one pre and one post an rTMS session.

During each fMRI scan, participants will be engaged in intersocial, competitive Domino task that involves mentalizing. rTMS manipulation, administered in a double-blind, counterbalanced fashion, includes one session each of excitatory (intermittent theta-burst stimulation, iTBS), inhibitory (continuous TBS, cTBS), and sham sequences. The rTMS will be guided with individualized electric-field modeling calculated from a structural MRI scan collected on the baseline session. This robust design is necessary to identify the optimal rTMS sequence to engage the right TPJ and the mentalizing network in ASD because firm conclusions about how best to modulate this network cannot be drawn from the few known published reports.

Investigators hypothesize that iTBS will result in increased, while cTBS in decreased MTR neural activity in the mentalizing network, with this being more pronounced in ASD, and sham resulting in no change. Understanding this mechanism will be the first and crucial step in validating rTMS of the right TPJ as a viable neural target to modulate neural circuit, and subsequently to modulate social-communication skills in ASD in future clinical studies. The significance of such a line of research should be considered in the context of the high prevalence of ASD and the dire need of developing effective interventions, especially for adults.

The three rTMS sessions will be compared within-subject and between-groups.