State-dependent modulation of brain co-activation patterns induced by individually targeted VLPFC stimulation during viewing emotional film clips

Accumulating evidence indicates that repetitive transcranial magnetic stimulation (rTMS) outcomes are state-dependent, with ongoing emotional states influencing neuromodulatory effects. However, how emotional context during stimulation influences subsequent brain functional state organization remains unclear. A total of 99 healthy participants were recruited in this study and allocated to one of three groups: active rTMS with sad film viewing (sad group), active rTMS with neutral film viewing (neutral group), or sham rTMS with sad film viewing (sham group). We combined rTMS during emotional film viewing with co-activation pattern (CAP) analysis to investigate the potential state-dependent effects of rTMS on brain dynamics. The fraction of time, resilience, and transition probabilities of CAPs were calculated to characterize brain dynamics. Four recurring CAPs were identified in this study. Relative to the sham group, participants following stimulation during the sad condition exhibited increased engagement of CAP 2, characterized by deactivations in the frontoparietal network and co-activations of the visual and somatomotor networks, along with decreased engagement of CAP 4, characterized by deactivations in the default mode network and co-activations of the somatomotor and salience networks. In contrast, the neutral condition exhibited attenuated effects. Furthermore, the change in transition probability from CAP 2 to CAP 3 was significantly greater in the sad condition than in the neutral condition. Together, these findings indicate that the effects of rTMS on brain dynamics may be modulated by the emotional context during stimulation. This work offers novel insights into the state-dependent modulation by rTMS and may help inform the optimization of therapeutic outcomes for rTMS interventions.