Arousal-related Memory Following Theta Burst Stimulation.

Aim 1 (cTBS): Behavioral outcomes will include relative order discrimination and temporal distance estimation. Data will be analyzed using linear mixed-effects models with fixed effects of stimulation condition (cTBS vs. Sham-cTBS), session (Week 2 vs. Week 4) within the cTBS group, counterbalanced across active and sham sessions, and their interaction, and random intercepts and slopes for participants to account for repeated measures. Continuous physiological arousal (heart rate) and subjective arousal ratings during encoding will be included as covariates. Neural analyses will focus on baseline fMRI collected during high-arousal movie clips. Regions of interest (ROIs) include the intraparietal sulcus, amygdala subregions (basolateral and central-medial), anterior and posterior hippocampus, and perirhinal cortex. IPS-linked network connectivity at baseline will be modeled as a predictor of behavioral sensitivity to cTBS, rather than measuring post-TBS changes. Multiple comparisons will be controlled using false discovery rate (FDR) correction at q \< .05.

Aim 2 (iTBS): Analyses will mirror Aim 1, substituting iTBS versus Sham-iTBS as the primary contrast. Behavioral indices of temporal memory and physiological arousal (heart rate, continuous ratings) during encoding will serve as primary outcomes. Baseline IPS connectivity measures will be used to examine individual susceptibility to iTBS modulation of behavior. ROI-level analyses will apply FDR correction (q \< .05). Voxelwise exploratory analyses of baseline functional connectivity may be conducted, with AFNI 3dLME modeling and cluster correction via 3dClustSim (voxelwise p \< 0.001, cluster α = 0.05).

Aim 3 - Individual Differences and Exploratory Contrasts: Individual difference analyses will incorporate baseline arousal indices, self-report measures (STAI, BAI, PCL-5), and participant-specific electric field (E-field) estimates from SimNIBS (individualized modeling software) as continuous moderators. Mixed-effects models will examine condition × moderator interactions to determine whether baseline physiology, self-report anxiety measures, or E-field strength predict differential behavioral sensitivity to cTBS or iTBS. Session order will be included as a covariate to account for potential practice or carryover effects. FDR correction (q \< .05) will be applied across all behavioral and ROI-level analyses.

cTBS: Each session will consist of a single continuous 600-pulse train delivered over 40 seconds, comprising 50 Hz bursts repeated at 5 Hz.

Device: Active TMS · Device: Sham TMS

iTBS: Each session (\~3.5 min) will consist of 20 trains of 10 seconds, comprising 2 seconds of 50 Hz bursts repeated at 5 Hz, with 8-second inter-train intervals, totaling 600 pulses per session.

Device: Active TMS · Device: Sham TMS

Theta Burst Stimulation (TBS): TBS will be delivered using a MagVenture MagPro X100 stimulator with a Cool-B65 A/P coil. One session of 600 pulses will be delivered per visit.

Theta Burst Stimulation (TBS): TBS will be delivered using a MagVenture MagPro X100 stimulator with a Cool-B65 A/P coil. One session of 600 pulses will be delivered per visit.

Plazo: Task will be administered immediately following TBS or sham stimulation at Weeks 2 and 4.

Participants will view sequences of emotionally arousing movie clips and judge the chronological order in which specific events occurred. Accuracy in determining sequential order will serve as a primary measure of temporal memory.

Plazo: Task will be administered immediately following TBS or sham stimulation at Weeks 2 and 4.

Following each clip sequence, participants will estimate the perceived temporal distance between events. These estimates will capture subjective distortions in the encoding of elapsed time under arousal.

Arousal-related Memory of Movie Clips During Individualized IPS Targeting fMRI and TBS.