Neuroscientists find brain cells that explain why stress keeps you up at night

If your anxiety before a big test or a high-stakes presentation has ever kept you up at night, you can rest easier knowing that scientists are trying to get to the bottom of matters.

A new study published this month in The Journal of Neuroscience explores how stress interferes with sleep, causing cascading negative effects on memory and other cognitive processes. By pinpointing the specific neural mechanisms involved in stress-related memory problems and sleep disruptions, scientists hope to figure out stress-zapping treatments in the future.

A group of researchers from the University of Pennsylvania School of Medicine’s Chronobiology and Sleep Institute simulated human stress in lab mice, restraining the animals so they couldn’t move. They then observed the animals’ neural activity while they slept and gave the mice a spatial memory test. Much like a human who gets stressed out before a big test, the mice slept poorly and showed memory deficits. 

The researchers went on to simulate the effects of the stress scenario without actually restraining the mice. By activating neurons that release the stress hormone corticotropin in a specific part of the hypothalamus known as the paraventricular nucleus, the research team stressed out the mice and went on to observe the same sleep and memory issues as if the animals had actually been restrained. 

When they blocked the same stress hormone-releasing neurons during the stress-inducing event, the mice slept a little better and had significantly less trouble during their spatial memory test—a hopeful clue in helping to understand how to mitigate the problems that stress creates in the human brain.

The researchers called the findings on the pathways of corticotropin-releasing hormone neurons in that region of the hypothalamus “an important step toward improving sleep and ameliorating cognitive deficits associated with stress-related disorders”—a conclusion that anyone tired of having that one same stress dream can definitely get behind.