Single prolonged stress blocks sleep homeostasis and pre-trauma sleep deprivation does not exacerbate the severity of trauma-induced fear-associated memory impairments

• DOI: 10.1371/journal.pone.0243743
• Publication Date: 2021-01-06T18:51:54Z
• Authors: Christopher J. Davis; Jason R. Gerstner; William M. Vander...
• Keywords: Male; Science; Severity of Illness Index; Extinction, Psychological; 03 medical and health sciences; 0302 clinical medicine; Animals; Homeostasis; Rats, Long-Evans; Memory Disorders; Q; R; Fear; Rats; 3. Good health; Mental Recall; Disease Progression; Medicine; Sleep Deprivation; Wounds and Injuries; Sleep Stages; Sleep; Stress, Psychological; Research Article

Sleep is intimately linked to cognitive performance and exposure to traumatic stress that leads to post-traumatic stress disorder (PTSD) impairs both sleep and cognitive function. However, the contribution of pre-trauma sleep loss to subsequent trauma-dependent fear-associated memory impairment remains unstudied. We hypothesized that sleep deprivation (SD) prior to trauma exposure may increase the severity of a PTSD-like phenotype in rats exposed to single prolonged stress (SPS), a rodent model of PTSD. Rats were exposed to SPS alone, SD alone, or a combination of SPS+SD and measures of fear-associated memory impairments and vigilance state changes were compared to a group of control animals not exposed to SPS or SD. We found that SPS, and SPS+SD animals showed impaired fear-associated memory processing and that the addition of SD to SPS did not further exaggerate the effect of SPS alone. Additionally, the combination of SPS with SD results in a unique homeostatic sleep duration phenotype when compared to SD, SPS, or control animals. SPS exposure following SD represses homeostatic rebound and eliminates sleep-deprivation-induced increases in NREM sleep delta power. This work identifies a unique time frame where trauma exposure and sleep interact and identifies this window of time as a potential therapeutic treatment window for staving off the negative consequences of trauma exposure.