0267 Infraslow Oscillations During Non-Rapid Eye Movement Sleep Across the Life Course

Abstract Introduction Sleep spindles, hallmark of stage 2 (N2) non-rapid eye movement (NREM) sleep, fluctuate in an infraslow oscillation (ISO; ~0.02Hz) regulated by the noradrenergic system and locus coeruleus. The temporal dynamics of ISOs, their frequency-domain extent, and how they evolve with age remain largely unexplored. Here, we examined how ISOs across a broad frequency range (0.5-30Hz) change across the life course, how different frequency bands synchronize in the infraslow domain, and how ISOs couple with phasic NREM sleep events to better understand their functional role in sleep neurophysiology. Methods We analyzed polysomnographic data (N=13,529, age: 3-85 years) from the National Sleep Research Resource. ISO power and peak frequency were derived from the frequency decomposition of the N2 spectrogram (0.5-30 Hz) and averaged across seven canonical bands: slow (0.5–1Hz), delta (1–4Hz), theta (4–7Hz), alpha (7–10Hz), slow sigma (10–12Hz), fast sigma (12–15Hz), and beta (15–30Hz). ISOs were characterized in the time domain after filtering the signals resulted from the first frequency decomposition in the 0.01-0.03Hz. Results All frequency bands exhibited infraslow modulation. ISO power and peak frequency showed significant age-related changes, with fast sigma power displaying an inverted U-shaped trajectory and the largest effect size (η²=.03, p.45 and ps