To further understand the impact of acute sleep deprivation and recovery sleep on the processing of emotional information the investigators will address and attempt to answer three questions, (i) how both undisturbed sleep and sleep deprivation affect the processing and retrieval of emotional information, (ii) what neural and psychophysiological mechanisms are associated with these behavioral effects, and (iii) to explore the ability of recovery sleep to reverse the effects of sleep deprivation. Together, these studies will provide a greater breadth and depth of knowledge concerning sleep's role in emotion processing and regulation. Given the growing societal tendency to view sleep as unproductive-foregoing it to lengthen work days and increase social opportunities- such knowledge would be of practical importance for understanding the role of sleep in healthy emotional functioning, particular for individuals experiencing periods of increased stress and emotional distress (e.g., new parents, hospital staff, or combat troops).

Goal 1: How does sleep deprivation impact emotion perception and memory processing? The investigators are interested in how an acute loss of sleep impairs our ability to properly perceive, consolidate, and retrieve emotional information. There has been research on the effect of sleep deprivation on broad areas of cognition, such as attention, working memory, and reasoning ability, but the impact of sleep loss on emotional processing and regulation remains largely unexplored. The investigators aim to characterize how sleep deprivation compared to undisturbed sleep affects the ability to accurately perceive emotion, how it alters the intensity with which emotions are perceived, and the effect that these changes have on the subsequent consolidation and memory retrieval for emotional compared to neutral information.

Goal 2: How are these changes reflected in the neural signal and with psychophysiological measures? The investigators will utilize functional magnetic resonance imaging (fMRI) and measures of autonomic reactivity (heart rate and skin conductance) to characterize the neural and psychophysiological mechanisms underlying these behavioral changes following sleep deprivation compared to a normal night of sleep. This will allow us to pinpoint the brain regions involved in changes following sleep deprivation, and associate these changes with effects on downstream physiological responses.

Goal 3: Can a nap after sleep deprivation restore normal processing of emotional memory and rescue the neural and autonomic markers of sleep deprivation? The investigators are interested in determining if a brief period of recovery sleep is enough to combat the behavioral, neural, and autonomic effects of acute sleep loss, thus a portion of the sleep-deprived participants will be given a 2-hour nap opportunity to quantify its restorative effects. Such information would form the foundation for future research extending and translating these findings into effective sleep-based interventions for healthy and clinical populations alike.

Inclusion Criteria:

• willing and able to follow the protocol
• willing and able to meet inclusion criteria for fMRI scanning
• willing to refrain from alcohol and recreational drugs for the duration of the protocol
• normal or corrected to normal vision is required

Exclusion Criteria:

• self-reported sleep disturbances
• left-handedness or ambidexterity
• a history of mental illness or neurological disorder
• the use of any drugs that could affect either sleep or cognitive functioning (e.g., sleeping pills or antidepressants)