Neurometabolites in the dlPFC and mPFC during SleepIntroduction: The medial prefrontal cortex (mPFC) and dorsolateral prefrontal cortex (dlPFC) are critical regions involved in cognitive and emotional regulation, yet their exact roles in sleep are not well understood. Given the First Night Effect (FNE), a phenomenon where sleep is disrupted in a novel environment, this study investigates how neurometabolite levels in the dlPFC and mPFC change during sleep and whether these regions differ in their involvement in sleep regulation. Methods: Two separate groups were analyzed for this study. The dlPFC group contained 14 participants in total, however, the amount of participants included in the data varied based on outliers. Similarly, the mPFC group contained 20 participants, however, outliers were excluded, with the participant being excluded varying. Participants completed two separate afternoon 90-minute nap sessions spaced one week apart. Magnetic resonance spectroscopy (MRS) was used to measure Glx (glutamine/glutamate) and GABA concentrations in the dlPFC and mPFC, while polysomnography (PSG) monitored sleep stages. Results: mPFC Glx levels significantly decreased from Day 1 to Day 2 while dlPFC Glx and GABA levels did not significantly change from wakefulness or differ between days. Higher mPFC Glx was associated with longer SOL, while greater dlPFC GABA was correlated with shorter SOL. There was a significant difference in Glx levels between the dlPFC and mPFC on Day 2. Last, age was positively correlated with dlPFC Glx levels. Conclusions: Results indicate that the mPFC and dlPFC play distinct roles in sleep, with their functions diverging overtime. While the mPFC appears to regulate excitatory activity in the transition to sleep and may contribute to wakefulness and delayed sleep onset until reaching NREM sleep, the dlPFC’s inhibitory function may facilitate sleep initiation.Kalyan, PoojacreatorSasaki, Yukathesis advisorBrown University. Neurosciencesponsor2025text_resourcesborn digitalEnglishSenior thesis (ScB)--Brown University, 2025NeurosciencethesesSleepNeuroscienceGABAPrefrontal cortexglutamatePolysomnographyAll rights reservedIn CopyrightAll Rights Reserved10.26300/5m4h-j352