Age-dependent functional changes are mirrored by declines in both the central nervous system (CNS) and in the autonomic nervous system (ANS) and have been related to pathological aging. Prior studies have demonstrated inter-dependence between central and autonomic events that contribute to cognition. Moreover, our group recently identified a temporal coupling of Autonomic and Central Events (ACEs) during sleep using electrocardiogram (ECG) to measure heart rate and electroencephalography (EEG) to measure sleeping brain rhythms . We showed that heart rate bursts (HRBs) temporally coincided with increased slow wave activity (SWA, 0.5-1Hz) and sigma activity (12-15Hz), followed by parasympathetic surge (RRHF) during non-rapid eye movement (NREM) sleep. Given that there are paralleling age-related declines in both the ANS and CNS, the current study investigated how these declining systems impact ACE coupling during daytime naps in older and younger adults. Despite, lower overall EEG activity during ACE windows in older adults, both younger and older adults showed HRB-modulated increases in SWA and sigma during wake and N2. However, older adults did not show the same pattern during N3. Furthermore, while younger adults demonstrated a RRHF increase only after HRBs, older adults showed an earlier rise and maintenance of the RRHF. Taken together, our results demonstrated that ACE activity remains generally intact with age. Given that age-related deterioration in autonomic and central nervous system activity is implicated in pathological decline, the general maintenance of alignment between the two systems is intriguing and may facilitate novel insights to aging.
bioRxiv Subject Collection: Neuroscience