Age and Sex Moderate the Effects of Sleep Quality on Resting-State Functional Connectivity in the Salience and Default Mode Network.

Aging often coincides with declining sleep quality, which can contribute to cognitive decline and increased dementia risk. Neuroimaging offers valuable insights into how poor sleep may affect brain health before cognitive or behavioral changes appear. Given the different prevalence rates of dementia between sexes, sleep disturbances might uniquely impact females relative to males. The goal of this study was to investigate how age and sex moderate the impact of sleep quality on resting-state functional connectivity. Based on the extant literature, we predicted that sleep quality would significantly impact connectivity in the default mode network, salience network, and the amygdala. Adults (N = 95), aged 20-74, completed the Pittsburgh Sleep Quality Index and underwent two 5-min sessions of resting-state MRI. Three-way interactions between age, sex, and sleep quality were found between the default mode network and the left superior parietal lobule. A two-way interaction between age and sleep quality was found between the salience network and right precentral/postcentral gyrus. No relationships were found using the amygdala as a seed region. Furthermore, sleep consistently contributed to the sleep quality-connectivity effects found for young adults and multiple sleep components varied in older adults. The results suggest that poor sleep affects the salience networks in both males and females, with variations in adaptive patterns depending on age. The default mode network appears particularly sensitive to sleep impairments in females, consistent with early desegregation of brain networks and increased risk for dementia. The alterations in young adults support the hyperarousal hypothesis as a potential contributor to insomnia.