Emotional reactivity to negative images reduced after wake time, preserved over sleep time
FRIDAY, Jan. 20 (HealthDay News) -- Sleep is associated with enhanced emotional memory and maintenance of emotional reactivity compared with wake, according to a study published in the Jan. 18 issue of The Journal of Neuroscience.
Bengi Baran, from the University of Massachusetts in Amherst, and colleagues used an incidental memory task in humans and collected valence and arousal ratings for 106 young adults (age 18 to 30 years) during two sleep sessions. The sessions were separated by either 12 hours of daytime wake or 12 hours including overnight sleep.
The researchers found that, for both negative and neutral pictures, recognition accuracy was greater following sleep, compared with wake. For negative pictures, the emotional reactivity was greatly reduced after wake time, whereas the negative emotional response was maintained over sleep time. Maintenance of this emotional reactivity correlated with increased time spent in REM sleep. Accuracy of recognition did not correlate with REM sleep.
"Here we provide the first examination of how memory processing relates to changes in emotional reactivity over sleep. Recognition memory was better following sleep compared with wake. Additionally, a period of wake was associated with attenuation of negative ratings, whereas a period of sleep was associated with relative maintenance of the initial negative ratings. Therefore sleep may, in fact, be protective of the emotional salience of a stimulus just as sleep protects the emotional memory," the authors write.
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