Abstract Introduction Mild Traumatic brain injuries (mTBIs) affect ~1–3 million people per year in the US alone. Mild TBIs can have lasting (>1 year) impacts on emotional reactivity and regulation. Sleep has also been shown to be significantly altered in individuals with a mTBI, even when tested over a year since the injury. Sleep quality is strongly linked with emotional stability and emotional memory. Therefore, one possible mediating factor between emotional reactivity and mTBIs is sleep. Reduced sleep quality following a mTBI may impair the emotional regulation that typically occurs across sleep. Thus, increasing total sleep time through a nap may help to alleviate some of the emotional symptoms. This study assessed whether individuals with a chronic mTBI showed differences in brain activity associated with emotional regulatory circuits, performance on an emotional reactivity task, and sleep physiology across a nap compared to controls. Methods Participants were 53 young adults (mTBI nap group: n=9; control nap group: n=16; mTBI wake group: n=11; control wake group: n=17). Following a nap, or an equivalent bout of wake (both recorded with polysomnography), participants completed an emotional Go/No-Go task in which they were asked to respond when a particular emotional valence was presented (neutral, fearful, or happy), and withhold a response when a different valence was presented. Results There was a significant main effect of emotion on reaction time (F(2, 98)=26.55, p < 0.001). Participants were slowest to respond to the neutral images. There was also a significant three way interaction between emotion, group, and condition (F(2,98)=4.085, p = 0.02). Conclusion While these results are preliminary, they support that both napping and mTBIs may impact emotional reactivity. Further, napping may help alleviate some of the chronic emotional dysregulation associated with mTBIs. Support Zampell Family Faculty Fellow