The Lim Laboratory is interested in the interface between sleep and common neurological disorders across the lifespan, such as traumatic brain injury (TBI), post-traumatic stress disorder (PTSD), autism, and Alzheimer’s disease. We analyze EEG data for sleep, oscillations, and other quantitative markers in order to identify biomarkers that predict disease trajectories and response to treatment. We also manipulate sleep quality and sleep amounts to assess the function of sleep in the progression of these disorders. Our research is conducted in both animal models and clinical research in human subjects with the ultimate goal of designing interventions to optimize sleep and enable better treatments in these vulnerable populations.
We have shown that mild traumatic brain injury (TBI) causes persistent sleep disturbances, and that dietary supplementation with branched chain amino acids improves wakefulness in mice. Notice how the hypnogram shows recovery of non-TBI sleep-wake patterns when an animal with a TBI has been eating a diet supplemented with BCAAs. We are currently investigating changes in orexin, glutamate, and GABA after TBI as they relate to control of sleep and wakefulness. We are also investigating sleep disturbances in combined TBI and PTSD in both mice and humans and how sleep quality and biomarkers of the sleep EEG relate to symptom severity in veterans with separate or combined TBI and PTSD.
Prairie voles are a highly social, monogamous wild rodent that are used as a model organism for pair bonding behavior. We are investigating the role of sleep on the developing brain. Fragmenting sleep in infant prairie voles prevented them from forming normal social bonds with other voles. We hope to investigate the underlying mechanisms of how sleep disruption during a sensitive developmental period affects behavioral circuits important for social functioning, and may contribute to developmental disorders such as autism spectrum disorder (ASD).