A combined fMRI and EMG study of emotional contagion following partial sleep deprivation in young and older humans

Abstract

Sleep deprivation is proposed to inhibit top-down-control in emotion processing, but it is unclear whether sleep deprivation affects emotional mimicry and contagion. Here, we aimed to investigate effects of partial sleep deprivation on emotional contagion and mimicry in young and older humans. Participants underwent partial sleep deprivation (3 h sleep opportunity at the end of night), crossed-over with a full sleep condition in a balanced order, followed by a functional magnetic resonance imaging and electromyography (EMG) experiment with viewing of emotional and neutral faces and ratings of emotional responses. The final sample for main analyses was n = 69 (n = 36 aged 20-30 years, n = 33 aged 65-75 years). Partial sleep deprivation caused decreased activation in fusiform gyri for angry faces and decreased ratings of happiness for all stimuli, but no significant effect on the amygdala. Older participants reported more anger compared to younger participants, but no age differences were seen in brain responses to emotional faces or sensitivity to partial sleep deprivation. No effect of the sleep manipulation was seen on EMG. In conclusion, emotional contagion, but not mimicry, was affected by sleep deprivation. Our results are consistent with the previously reported increased negativity bias after insufficient sleep.The Stockholm sleepy brain study: effects of sleep deprivation on cognitive and emotional processing in young and old. https://clinicaltrials.gov/ct2/show/NCT02000076 .

Figure 1

Experimental paradigm (adapted from Nilsonne et al. 2016). Between every set of three, participants were asked to rate how happy they felt and how angry they felt, using a visual analogue scale ranging from 0 to 100. The face shown in the figure is one of the stimuli (AF01HAS) from the KDEF data base that was used in the experiment. Written consent exists for the publication of KDEF sample images in scientific papers; see https://www.kdef.se/home/using%20and%20publishing%20kdef%20and%20akdef.html.

Figure 2

Rated emotional experience, model estimates with 95% confidence estimates.

Figure 3

EMG activity, model estimates with 95% confidence estimates.

Figure 4

Regions of interest, shown on gray matter mask including only voxels with complete coverage across all participants. Left: amygdala ROI:s from Jülich atlas. Right: fusiform face area ROI:s from Henson and Mouchlinaitis 2007; spherical centered on top coordinates. ROI:s can be visualised and downloaded from https://neurovault.org/collections/RLWUZRQN/.