Emotional Memory Moderates the Relationship Between Sigma Activity and Sleep-Related Improvement in Affect.

Bethany J Jones,Ahren B Fitzroy,Rebecca M C Spencer

doi:10.3389/fpsyg.2019.00500

Bethany J Jones, Ahren B Fitzroy + Show 1 more

Open Access

https://doi.org/10.3389/fpsyg.2019.00500

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Abstract

Sleep is essential for regulating mood and affect, and it also consolidates emotional memories. The mechanisms underlying these effects may overlap. Here, we investigated whether the influence of sleep on affect may be moderated by emotional memory consolidation. Young adults viewed 45 negative and 45 neutral pictures before taking an afternoon nap measured with polysomnography. Following the nap period, participants viewed the same pictures intermixed with novel ones and indicated whether they remembered each picture. Affect was measured with the Positive and Negative Affect Schedule (PANAS) at baseline before the initial picture viewing task, immediately following the initial picture viewing task, and following the nap. The ratio of positive to negative affect declined over the task period and recovered over the nap period. When controlling for pre-nap affect, NREM sigma activity significantly predicted post-nap affect. Memory for negative pictures moderated this relationship such that a positive association between sigma activity and affect occurred when memory was low but not when memory was high. These results indicate that emotional memory consolidation influences the relationship between nap physiology and mood.

Highlights

Sleep is important for multiple domains of emotional functioning
We show that percent time spent in NREM2 sleep as well as NREM sigma density during an afternoon nap predict recovery of affect over the nap period following a decline related to viewing negative pictures
The relationship between sigma density and affect was moderated by memory performance for negative pictures

Summary

Introduction

Sleep is important for multiple domains of emotional functioning. One such domain is the regulation of mood and affect. Sleep disturbances and alterations are prevalent among those with mood disorders and may contribute to the development of these disorders (Meerlo et al, 2015; Murphy and Peterson, 2015). The mechanisms underlying the contribution of sleep to daily mood/affect in healthy individuals are not well understood, but REM sleep and SWS are both implicated by prior work. In healthy male adults who underwent two nights of normal sleep and two nights of sleep restriction, reduced REM sleep was associated with reduced functional connectivity between the medial prefrontal cortex and

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