The role of emotion has virtually been ignored in basic sleep research, possibly because of a lack of established models. In the previous award period, we established that both shock training and shock associated fearful cues and contexts in the conditioned fear model of emotional learning produced similar effects on sleep, most prominently a relatively selective suppression of rapid eye movement sleep (REM). While there is a well-developed body of knowledge on the effects of fear conditioning on behavior and physiology seen immediately after the presentation of fearful cues and contexts, how these experiences influence sleep is only now receiving attention. Filling this knowledge gap should increase our understanding of how stress and emotion, particularly fear and anxiety, affect sleep. Such understanding may be critical for insight into sleep disorders such as insomnia and into emotional disorders in which sleep is affected. It also may be especially relevant to posttraumatic stress disorder (PTSD), which is typically characterized by a prominent sleep disturbance in the aftermath of a psychologically traumatic stressor. Our objectives are: 1) to identify situational and stimulus qualities that directionally impact sleep (either increase or decrease) and behavior and determine their time course of action, and 2) to examine neurobiological systems potentially responsible for conditioned changes in sleep and behavior. To accomplish these objectives, we plan to examine the influence of inescapable, escapable and avoidable shock-training / shock-associated cues and contexts on sleep and behavior, and determine the immediate and longer-term effects of fear conditioning on sleep and behavior. We will also examine the role of CRH in immediate and longer-term effects of fear conditioning on sleep and behavior, and we will determine the fear-induced changes in regional noradrenergic/serotonergic/GABAergic release in amygdala, hippocampus and nucleus pontis oralis (NPO) that may be associated with fear-induced alterations in sleep. Our hypothesis is that stressor (shock) controllability or uncontrollability and the neurobiological concomitants of each type of situation are associated with temporary and persisting alterations in sleep and behavior, respectively. The rationale is that identifying stimulus and situational qualities that can produce immediate and longer-term changes in sleep and behavior, and neural systems involved in these changes, will provide insight essential for understanding how stressful and traumatic events are related to sleep pathology. The results will identify stimulus conditions involved in the influence of fearful emotion and anxiety on sleep, determine factors relating to the persisting influence of stressful events on sleep, and they will examine neural mechanisms potentially involved in the influence of stressful emotional situations on sleep. These studies will contribute to our understanding of how behavioral stress, emotion and environmental factors influence sleep and behavior, and they will advance our understanding of both immediate and persisting effects of fear conditioning.
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