Autonomic/Central Coupling during Daytime Sleep Differs between Older and Younger People

Abstract

Age-dependent functional changes are mirrored by declines in both the central the autonomic nervous systems and have been related to pathological aging. Prior studies in our group have identified a temporal coupling of Autonomic and Central Events (ACEs) during sleep using electrocardiogram to measure heart rate and electroencephalography to measure brain rhythms, with 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. ACEs predicted working memory (WM) improvement in young adults. Given that there are paralleling age-related declines in both the ANS and CNS, the current study investigated differences in ACE activity during daytime sleep in older and younger adults and their functional impact on working memory. Compared to youngers, older adults showed lower amplitude of ACEs during NREM sleep, but no age-related difference during Wake. Furthermore, while younger adults demonstrated a parasympathetic surge after HRBs, older adults showed a different pattern, with a earlier rise and maintenance of the RRHF. Finally, we examined whether ACE predicted WM in older adults. We found that older adults with good WM show stronger coupling, whereas low WM performers had less robust ACE activity. Taken together, our results demonstrated that autonomic-central coupling declines with age, with possible links to deterioration in WM function. Given that age-related deterioration in autonomic and central nervous system activity is implicated in pathological decline, the current findings may facilitate novel insights to the cognitive neuroscience of aging.