There is a fundamental gap in our understanding of how sleep loss alters daytime emotion processes. In particular, no previous study has investigated the extent to which sleep loss alters multisensory emotion processes even though the consequences of sleep loss rarely involve the impact of emotional stimuli on a discrete sensory process, but rather, involve the consequence of altered emotion processing in one sensory modality on processing in a different sensory modality. The overall goal of the proposed research is to show the extent to which sleep loss blunts emotionally driven sensory integration. The rationale for the proposed research is that confirmation of our aims will translate into a model of how daily sleep restriction (commonly experienced by humans) can lead to daily life challenges in proper emotional processing. Guided by strong preliminary data, our hypothesis will be tested by two specific aims: Aim 1) Test the prediction that, consistent with our preliminary data, sleep deprivation will reduce visual-auditory affective priming. Aim 2) Show that, consistent with current behavioral findings, REM sleep is particularly critical for preserving emotion processes. We will test our aims by assessing affective priming after late sleep deprivation (REM-rich) compared to early sleep deprivation (slow wave sleep, SWS-rich). We hypothesize that due to the role of REM sleep in preserving waking emotion processes, late sleep deprivation will show greater blunting of affective priming measures compared to early sleep deprivation. The proposed research is significant because a comprehensive investigation into the effects of total sleep deprivation, SWS deprivation, and REM sleep loss on affectively-charged multisensory processing, such as the proposed study, can help identify repercussions in those careers which inherently expose individuals to emotional situations after sleep loss. Moreover, our genetic individual differences findings will set the stage for novel approaches for the treatment of affective disorders.