Spatiospectral signatures of stomach-brain synchrony

While cognitive neuroscience has increasingly recognized the brain-body connection, the temporal dynamics of how the stomachs intrinsic rhythm ([~]0.05 Hz) modulates human neural activity remain poorly understood. Leveraging high-resolution magneto-encephalography (MEG) and novel high-density electrogastrography (EGG), we provide the first comprehensive spatiotemporal mapping of human gastric-brain coupling at rest. Our circular-linear correlation approach revealed widespread, broadband phase-amplitude coupling between the gastric rhythm and spontaneous cortical oscillations across delta, theta, alpha, and beta bands. Using nonnegative matrix factorization, we identified distinct spatiospectral fingerprints that significantly overlap with the known fMRI-based gastric resting-state network. Crucially, we discovered a consistent preferred gastric phase for these modulations, i.e. during the transition between stomach waves, that was stable across brain regions, frequencies, and time. These findings suggest that the gastric rhythm - potentially in unison with other physiological signals - provides a stable, global scaffold for large-scale oscillatory brain organization. By unravelling these spectral signatures, our results establish the stomach as a critical driver of the temporal coordination of human brain dynamics.