BACKGROUND: Segmenting continuous experience into discrete units-event segmentation-is fundamental for situational awareness and adaptive action. Based on Event Segmentation Theory (EST), we used auricular transcutaneous vagus nerve stimulation (atVNS) to test whether the control of event segmentation is moderated by norepinephrine (NE) and/or GABAergic systems.

METHODS: Healthy adults (n = 40) completed a double-blind, counterbalanced experiment in which they watched a narrative movie and indicated perceived event boundaries under active atVNS and sham stimulation while EEG was recorded. Multivariate pattern analysis (MVPA) quantified the decodability of boundary interval (BI) vs. no-boundary interval (NBI), and EEG source reconstruction assessed cortical activation.

RESULTS: Relative to sham, active atVNS reduced the likelihood of segmentation. Converging neurophysiological evidence mirrored this behavioral effect: MVPA revealed lower decoding accuracy for BI and NBI, indicating less distinct neural representational patterns. Source reconstruction showed reduced activation in prefrontal cortex, a region involved in working memory.

CONCLUSIONS: Across behavioral and neural measures, atVNS stabilized ongoing event representation and restricted the updating of the current event working model, consistent with a GABAergic modulation of event segmentation. These findings extend prior work linking atVNS to working memory gating and demonstrate its impact on an ecologically relevant cognitive process-event segmentation.