Sleep disorders may do more than leave people feeling tired. New research from FIU shows these sleep disorder effects are associated with structural changes in brain regions involved in attention, motivation and decision-making.
The findings, published in the Nature Portfolio journal Scientific Reports, provide one of the most comprehensive looks to date at how different sleep disorders affect the brain and could help pave the way for earlier diagnosis and more targeted treatments.
Sleep disorders affect an estimated 50 to 70 million Americans. To better understand what happens in the brain across a range of sleep disorders, researchers at FIU's Center for Children and Families conducted a meta-analysis of 57 brain imaging studies. The study is among the first to examine multiple types of sleep disorders side by side, looking for both shared and distinct patterns in brain structure.
Researchers analyzed two major categories: dyssomnias, including insomnia and sleep apnea, which make it difficult to fall or stay asleep; and parasomnias, including sleepwalking, nightmare disorder and sleep terrors, which disrupt the sleep cycle itself.
"As more people recognize how important sleep is, there's growing urgency to understand what's happening in the brain," said Matthew Sutherland, a cognitive neuroscientist at FIU and senior author of the study. "By bringing together results from many studies, this research gives us a clearer picture of how sleep disorders affect brain structure and function and where we need to focus next."
Across both categories, researchers identified decreases in the thalamus, a brain region critical for filtering information, maintaining focus and supporting higher-level thinking. They specifically found structural changes in the pulvinar, part of the thalamus that helps direct attention and regulate cognitive control.
These changes were also linked to broader brain networks involved in focus and task performance, helping explain why disrupted sleep can contribute to slower responses, impaired decision-making and an increased risk of mistakes and accidents.
"Most research looks at sleep disorders one at a time," said Katharine Crooks, a recent FIU cognitive neuroscience doctoral graduate and lead author of the study. "By looking across many studies, we found shared patterns in the brain that help explain why sleep problems can impact focus, decision-making and everyday functioning. With so many people struggling with sleep, understanding what is happening in the brain is key to finding better interventions, diagnostic tools and personalized treatments."
The study also uncovered patterns unique to parasomnias. Researchers found structural changes in the posterior cingulate cortex, a region involved in motivation, decision-making and emotional regulation. These findings may help explain why people with parasomnias sometimes experience changes in mood, behavior and emotional control.
Matthew Sutherland, director of Florida International University's Neuroinformatics and Brain Connectivity Lab and an associate professor of psychology in the College of Arts, Sciences & Education, reviews brain imaging scans in his laboratory at FIU's Center for Children and Families. FIU photo by Taimy Alvarez)
Researchers did not find consistent structural changes unique to dyssomnias, suggesting different sleep disorders may affect the brain in distinct ways depending on how sleep is disrupted.
The team hopes the findings will help inform future interventions designed not only to improve sleep but also to protect the brain systems that support attention, decision-making and emotional regulation.
Next, researchers plan to investigate specific parasomnias, such as sleepwalking and REM sleep behavior disorder, and explore whether the observed brain changes are a cause of sleep disorders, a consequence of them or both.
