Poor sleep alters brain communication in distinct ways depending on a person's age and biological sex, according to a study published in the journal Neurobiology of Aging and announced on Jul. 14. The research included psychology experts from Binghamton University, State University of New York, as well as collaborators from The University of Alabama.
The team analyzed brain scans from more than 1,300 participants to examine how rest-related brain network connectivity changes among people reporting poor sleep quality. In college-age adults with poor sleep, researchers found overconnected regions involved in movement, which may indicate that their bodies are not physically prepared for sleep. Conversely, older adults—typically those aged 65 and above—showed under-connected movement regions but hyperconnectivity in areas linked to cognition.
Associate Professor Ian McDonough said that older women with poor sleep displayed abnormal hyperconnectivity between the Default Mode Network (DMN), responsible for internal thoughts and memory, and the Frontal Parietal Network (FPN), associated with sustained attention and working memory. "This over-communication pattern was directly linked to poorer memory performance and mirrors brain wiring patterns seen in the preclinical, silent stages of Alzheimer's disease," McDonough said.
The reasons behind these differences remain unclear. Researchers suggest that older adults might become habituated to hyperarousal or develop coping mechanisms such as taking sleep-related medications. Rumination—overthinking often related to anxiety or depression—may also play a role regardless of age or personal circumstances. "One strong possibility is that people who have a lot of running thoughts right before bed are not in a calm state, but rather more of an agitated state," McDonough said.
McDonough also discussed the relationship between depression and dementia: "Depression has a complicated relationship with dementia, with some studies showing a link between the two conditions," McDonough said. He added that cognitive function can improve when depression is treated. The study raises questions about whether abnormal brain connections cause sleep dysfunction or vice versa; however, it found that increased DMN-FPN connectivity was associated with poorer cognition over time.
Growing evidence suggests early signs of declining brain health may be reflected by increased connectivity between certain networks like the DMN. For young adults struggling with arousal before bedtime, strategies such as journaling may help reduce racing thoughts; for older adults facing different mechanisms behind poor sleep quality, consulting a physician is recommended. "If connectivity changes do precede sleep loss, then strengthening brain networks could be one solution," McDonough said.
