Noradrenergic infraslow rhythm during sleep is the critical link between heart-rate dynamics and memory consolidation.

Infraslow heart rate variability during sleep, driven by locus coeruleus activity, predicts memory consolidation across species with a critical LC activity threshold.

• Why it matters: Understanding how sleep-related autonomic signals relate to memory processes can reveal mechanisms underlying cognitive function and neurodegenerative disease, addressing a key gap in sleep neuroscience.
• What they did: The study used optogenetics and cross-species analysis to show that LC activity modulates infraslow HR fluctuations during NREM sleep, with HR deceleration amplitude correlating with spindle activity and memory performance in mice and humans.
• The result: Findings suggest infraslow HR variability as a non-invasive marker of brainstem function and memory processing, offering potential for early detection of neuromodulatory dysfunction in neurodegenerative diseases.