Preferential consolidation of emotional reactivity during sleep: A systematic review and meta-analysis

Abstract

Many studies have investigated whether sleep affects cognitively unmodulated reactivity to emotional stimuli. These studies operationalize emotion regulation by using subjective and/or objective measures to compare pre- and post-sleep reactivity to the same emotional stimuli. Findings have been inconsistent: some show that sleep attenuates emotional reactivity, whereas others report enhanced or maintained reactivity. Across-study methodological differences may account for discrepant findings. To resolve the questions of whether sleep leads to the attenuation, enhancement, or maintenance of emotional reactivity, and under which experimental conditions particular effects are observed, we undertook a synthesized narrative and meta-analytic approach. We searched PubMed, PsycINFO, PsycARTICLES, Web of Science, and Cochrane Library databases for relevant articles, using search terms determined a priori and search limits of language = English, participants = human, and dates = January 2006–June 2021. Our final sample included 24 studies that investigated changes in emotional reactivity in response to negatively and/or positively valenced material compared to neutral material over a period of sleep compared to a matched period of waking. Primary analyses used random effects modeling to investigate whether sleep preferentially modulates reactivity in response to emotional stimuli; secondary analyses examined potential moderators of the effect. Results showed that sleep (or equivalent periods of wakefulness) did not significantly affect psychophysiological measures of reactivity to negative or neutral stimuli. However, self-reported arousal ratings of negative stimuli were significantly increased post-sleep but not post-waking. Sub-group analyses indicated that (a) sleep-deprived participants, compared to those who slept or who experienced daytime waking, reacted more strongly and negatively in response to positive stimuli; (b) nap-exposed participants, compared to those who remained awake or who slept a full night, rated negative pictures less negatively; and (c) participants who did not obtain substantial REM sleep, compared to those who did and those exposed to waking conditions, had attenuated reactivity to neutral stimuli. We conclude that sleep may affect emotional reactivity, but that studies need more consistency in methodology, commitment to collecting both psychophysiological and self-report measures, and should report REM sleep parameters. Using these methodological principles would promote a better understanding of under which conditions particular effects are observed.

Orexin Neurons to Sublaterodorsal Tegmental Nucleus Pathway Prevents Sleep Onset REM Sleep-Like Behavior by Relieving the REM Sleep Pressure

“…We next evaluated whether the contribution of the orexin-SLD pathway in REM sleep homeostasis was more importantly required when REM sleep need was elevated, because this kind of elevation is a common feature crucial for several important brain functions, such as emotion regulation and energy balance [ 28 , 29 ]. To test this, we created a REM sleep high-need condition through REM sleep deprivation (RSD) for 24 h (Fig.…”

“…Due to both deficits in REM sleep timing and consolidation, severe REM sleep fragmentation and delayed response to REM sleep need finally appear in the orexin SLD-caspase mice, implying the important significance of the orexin-SLD pathway in REM sleep homeostatic response. It should be noted that efficient homeostatic regulation of REM sleep is a crucial process for the homeostasis of several important functions, including emotion processing, motor control, and also energy balance [ 28 , 29 ]. Consistently, the disturbed REM sleep homeostasis has been reported to cause several related clinical disorders, such as depression, attention-deficit hyperactivity disorder (ADHD), and overweight [ 54 – 57 ].…”