Neurons in a brain structure called the paraventricular nucleus help translate stress into poor sleep and memory.Credit: Filmstax/Getty
Scientists have identified a group of neurons that might explain the mechanism behind how stress gives rise to problems with sleep and memory.
The study — published last week in The Journal of Neuroscience1 — shows that neurons in a brain area called the hypothalamus mediate the effects of stress on sleep and memory, potentially providing a new target for the treatment of stress-related sleep disorders.
Previous work has shown that within the hypothalamus, neurons in a structure called the paraventricular nucleus communicate with other areas important for sleep and memory. The neurons of the paraventricular nucleus release a hormone called corticotropin and have a role in regulating stress. But the neural mechanisms underlying the effect of stress on sleep and memory have remained elusive.
For co-author Shinjae Chung, a neuroscientist at the University of Pennsylvania in Philadelphia, the question of how exactly how stress affects these processes is personal, because, she says, “I experience a lot of sleep problems when I’m stressed”. She adds that “when I have an exam deadline, I have a tendency to have bad sleep that really affects my score the next day”.
Losing sleep
To study how neurons in the paraventricular nucleus translate stress into sleep and memory problems, the researchers put laboratory mice through a stressful experience by physically restraining the animals in a plastic tube. The team then tested the creatures’ spatial memory and monitored their brain activity as they slept.
As expected, the stressed mice showed difficulty sleeping and struggled with memory when tested the following day. Stimulating neurons in the paraventricular nucleus mimicked these effects, whereas blocking these neurons resulted in modest improvements in sleep, and more substantial gains in memory performance.
