Sleep is the first pillar of successful recovery...
The new research, led by Prof. Talma Hendler of Tel Aviv University (TAU) in Israel, identifies the neurological mechanism responsible for disturbed emotion regulation and increased anxiety due to lack of sleep.
It also shows how sleep deprivation can affect our ability to regulate emotions and allocate brain resources for cognitive processing.
Researchers kept 18 adults awake all night and had them take two rounds of tests while undergoing brain mapping using functional magnetic resonance imaging (fMRI) and/or an electroencephalogram (EEG).
The first test was taken after a good night's sleep and the second after spending a night awake in the lab.
In the first test, participants had to describe the direction in which small yellow dots moved over distracting images. These images were "positively emotional" (a cat), "negatively emotional" (a mutilated body) or "neutral" (a spoon).
Sleepless night changes emotional perception
After a good night's rest, participants 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.
After a wakeful night, however, they performed badly in both the neutral and the emotional image tests, and their electrical brain responses did not reflect a highly different response to the emotional images, indicating a lower degree of regulatory processing.
Fast facts about sleep
- 43% of Americans aged 13-64 years say they do not get enough sleep
- 60% have problems sleeping most nights
- Most Americans feel that 7.5 hours is an appropriate length of time to sleep.
TAU graduate student Eti Ben-Simon, who conducted the experiment, believes that sleep deprivation may universally impair judgment, but it is more likely that a lack of sleep causes neutral images to provoke an emotional response.
The second test examined concentration levels.
Participants inside an fMRI scanner had to complete a task that demanded their attention to press a key or button, while ignoring distracting background pictures with emotional or neutral content.
This time, researchers measured activity levels in different parts of the brain as participants completed the cognitive task.
After only one night without sleep, participants were distracted by every single image (neutral and emotional), while well-rested participants only found the emotional images distracting.
The effect was indicated by activity change, or what Prof. Hendler calls "a change in the emotional specificity" of the amygdala.