Low-quality sleep is nothing new. However, the COVID-19 pandemic brought to the forefront the topic of stress and how it plays a role in negatively affecting sleep quality.
To understand the role stress plays in altering sleep quality, Professor Kevin Beier from the Department of Neurobiology and Behavior teamed up with longtime collaborators Shinjae Chung and Franz Weber from the University of Pennsylvania. The multiyear effort to shed light on the circuits that underly sleep concluded with the recent publication of their joint paper in the Proceedings of the National Academy of Sciences.
By exposing mice to social stressors, the team found microarousals occurring during nonrapid eye movement (NREM) sleep, an essential phase of the natural sleep cycle. These microarousals negatively affected all phases of sleep and were caused by an increase in activity of noradrenergic neurons in the part of the brain called the locus coeruleus, which results in increased alertness.
What’s more, when the team activated the noradrenergic neurons in unstressed mice, it elicited the same sleep disturbance response as the stressed mice. And when the neurons were inhibited, the mice’s sleep cycles returned to normal.
“Our study supports a critical role for these noradrenergic cells in determining sleep quality,” said Professor Beier. “It also extends previous observations by implicating key brain cells that receive the information conveyed by these noradrenergic neurons, which is a critical step in understanding exactly how and why our sleep is negatively impacted by stress.”
By upon previous observations of noradrenergic cells, this study might one day lead to a deeper understanding of how our brains manage stress.
And while it may be years before stressed individuals can take a pill to inhibit noradrenergic neurons for a better night’s sleep, we can rest easy knowing we understand a little bit more about what goes on inside our brains.
Learn more about the Beier Lab.