Dynamic stomach-brain electrical coupling in human sleep

Sleep involves continuous communication between the brain and body, yet the dynamics of peripheral signals during human sleep remain poorly understood. Here we tested whether gastric electrophysiology exhibits structured dynamics that align with cortical oscillations across sleep. Simultaneous high-density electroencephalography (EEG) and electrogastrography (EGG) were recorded in sixty healthy adults across multiple nights. Gastric activity persisted throughout sleep, increased during NREM, and showed infraslow amplitude fluctuations that were selectively amplified during NREM. Gastric rhythms synchronized with cortical slow oscillations and sleep spindles, with gastric power tracking spindle occurrence and infraslow fluctuations in cortical sigma power. Stomach-brain coupling predicted next-day memory recall beyond cortical measures alone, and gastric infraslow dynamics predicted subjective sleep quality beyond standard polysomnographic and cardiac measures. Together these findings position the human stomach as a peripheral oscillator whose dynamics track thalamocortical activity during sleep, reframing sleep as a coordinated multi-organ state.