Cardiovascular Activity Predominantly Modulates Brain Dynamics in Non-REM Sleep Transitions

This study explores the brain-heart axis and its directional control dynamics across various sleep stages using electroencephalography and electrocardiogram data from publicly available whole-night recordings of 50 healthy individuals. Utilizing a validated functional brain-heart interplay (BHI) mathematical model, we identified a decrease in central control over peripheral neural activity regulating heartbeat dynamics during non-REM sleep. In contrast, an increase in sympathovagal activity influencing cortical function was observed during deep sleep, particularly in Non-REM3, compared to light sleep and REM phases. These results indicate a dynamic shift in the functional balance of the brain-heart axis and related BHI throughout sleep stages, characterized by predominant central control during wakefulness and enhanced bodily neuro-cardiac-autonomic regulation during deep sleep.