Cranky or grumpy after a long night? Your brain’s ability to regulate emotions is probably compromised by fatigue.
A new study from Isreal’s Tel Aviv University has identified the neurological mechanism responsible for disturbed emotion regulation and increased anxiety due to only one night’s lack of sleep. The research reveals the changes sleep deprivation can impose on our ability to regulate emotions and allocate brain resources for cognitive processing.
“Prior to our study, it was not clear what was responsible for the emotional impairments triggered by sleep loss,” said the research team’s leader, Prof. Talma Hendler. “We assumed that sleep loss would intensify the processing of emotional images and thus impede brain capacity for executive functions. We were actually surprised to find that it significantly impacts the processing of both neutral and emotionally-charged images.
“It turns out we lose our neutrality. The ability of the brain to tell what’s important is compromised. It’s as if suddenly everything is important,” she said.
For the purpose of the study, 18 adults were given two rounds of tests, first following a good night’s sleep and the second following a night of lack of sleep in the lab. One of the tests required participants to describe in which direction small yellow dots moved over distracting images. These images were “positively emotional,” “negatively emotional” or “neutral.”
When participants had a good night’s rest, they identified the direction of the dots hovering over the neutral images faster and more accurately, and their EEG pointed to differing neurological responses to neutral and emotional distractors. When sleep-deprived, however, participants performed badly in the cases of both the neutral and the emotional images, and their electrical brain responses, as measured by EEG, did not reflect a highly different response to the emotional images. This pointed to decreased regulatory processing.
The researchers also conducted a second experiment testing concentration levels. Participants were shown neutral and emotional images while performing a task demanding their attention while ignoring distracting background pictures with emotional or neutral content while the participants were inside an fMRI scanner. This time researchers measured activity levels in different parts of the brain as they completed the cognitive task.
The team found that participants after only one night of lack of sleep were distracted by every single image (neutral and emotional), while well-rested participants were only distracted by emotional images. The effect was indicated by activity change in the amygdala, a major limbic node responsible for emotional processing in the brain.
The new findings emphasize the vital role sleep plays in maintaining good emotional balance in our life for promoting mental health. The researchers are currently examining how novel methods for sleep intervention (mostly focusing on REM sleep) may help reduce the emotional dysregulation seen in anxiety, depression, and traumatic stress disorders.