Rutgers University scientists reveal that the quality of sleep may be associated with the regions of the brain involved in fear learning. The work was published yesterday and can be found in JNeurosci.
Shira Lupkin and Itamar Lerner, two of the study's authors, had subjects monitor their sleep for one week using sleep monitoring tools that kept track of brain waves and arm movements. The subjects then participated in a neuroimaging experiment during which they learned to associate a neutral image with a mild electric shock. They found that subjects who had a greater amount of time in rapid eye movement (REM) sleep showed a weaker link in connectivity between their amygdala, hippocampus and ventromedial prefrontal cortex during fear learning.
The results were replicated using polysomnographic monitoring of sleep during the night just prior to fear learning and the results remained considered. The findings hint at the idea that REM sleep reduces levels of norepinephrine in the brain, which may dampen an individual's sensitivity to fearful stimuli.
Image: More time in Rapid-Eye-Movement sleep predicted less connectivity between key brain regions that are involved in fear learning. Image courtesy of Itamar Lerner and Shira Lupkin.