An appraisal of electrogastrogram-electroencephalogram interactions in healthy adults

In recent years, the intricate interplay between the brain and gastrointestinal system has garnered significant attention, particularly in the context of mental and physical health. A critical aspect of this relationship is the gut-brain axis, a bidirectional communication network linking the central nervous system (CNS) and enteric nervous system (ENS). In this study, we investigated phase–amplitude coupling (PAC) between infra-slow gastric rhythms and cortical alpha activity (8–13 Hz) using simultaneous EEG and EGG recordings in 23 healthy adults at rest. To systematically assess how analytic decisions shape coupling outcomes, we implemented a multiverse analysis comprising 216 theoretically defensible preprocessing pipelines. Results revealed robust and region specific PAC effects, with the left fronto-central region showing the most consistent evidence of gut–brain coupling across pipelines. Specification curve analysis identified key preprocessing parameters, such as FIR filtering and manual ICA, as associated with stronger and more stable coupling effects. These findings were supported by permutation based inference tests and topographical inspection of alpha-band activity. While prior studies have often relied on single analytic pipelines, our approach underscored the importance of evaluating result sensitivity across the analytic space. This research demonstrated how multiverse analysis could improve inferential transparency and methodological rigor in gut-brain electrophysiology. Rather than proposing definitive conclusions about physiological mechanisms, our findings provided a principled foundation for future research by clarifying which analytic choices matter, which do not, and how such variability may shape theoretical interpretations in gut–brain coupling studies.