Beyond Correlation: Causal Brain-Heart Coupling During Sleep Arousals via Convergent Cross Mapping

Abstract

Sleep arousals are transient events known to elicit concurrent cortical and autonomic responses, yet the directional causal structure of brain-heart coupling during these events remains unexplored. In this study, we investigated nonlinear directed brain-heart interactions during sleep arousals using Convergent Cross Mapping (CCM).We extracted eventlocked 120 s segments from simultaneous single-channel EEG and ECG full-night recordings of 53 participants. We computed EEG amplitude envelopes for sleep-specific frequency bands and heart rate variability series. Bidirectional CCM using 30-s windows with a 1-s sliding step provided time-varying coupling estimates across all arousals. We validated coupling significance using phase-randomized surrogate data, and tested band-selective coupling changes using linear mixedeffects models. Results indicated that brain-to-heart coupling dominated in all bands and pre- and post-arousal. Heart-tobrain coupling increased significantly in all EEG bands prearousal and recovered in post-arousal, indicating autonomiccortical signaling as a hallmark of sleep arousal dynamics.