Mouse Study Finds Chronic Sleep Loss in Adolescence May Increase Risk for Mental DisordersA new animal study may influence parents to keep a closer check on their teens’ sleeping habits. Researchers from the University of Wisconsin-Madison discovered sleep restriction in adolescent mice prevented the balanced growth of brain synapses.

Synapses are the site where nerve cells connect and communication occurs.

“One possible implication of our study is that if you lose too much sleep during adolescence, especially chronically, there may be lasting consequences in terms of the wiring of the brain,” says Dr. Chiara Cirelli.

Mental illnesses such as schizophrenia tend to start during adolescence but the exact reasons remain unclear. “Adolescence is a sensitive period of development during which the brain changes dramatically,” Cirelli says.

“There is a massive remodeling of nerve circuits, with many new synapses formed and then eliminated.”

The study appears in the advance online publication of the journal Nature Neuroscience.

Cirelli and colleagues wanted to see how alterations to the sleep-wake cycle affected the anatomy of the developing adolescent brain.

Their earlier studies showed that during sleep, synapses in adult rodents and flies become weaker and smaller, presumably preparing them for another period of wakefulness when synapses will strengthen again and become larger in response to ever-changing experiences and learning.

They call this the synaptic homeostasis hypothesis of sleep.

In the current study, they compared adolescent mice that for eight to 10 hours were spontaneously awake, allowed to sleep or forced to stay awake.

“These results using acute manipulations of just eight to 10 hours show that the time spent asleep or awake affects how many synapses are being formed or removed in the adolescent brain,” Cirelli says.

“The important next question is what happens with chronic sleep restriction, a condition that many adolescents are often experiencing.”

The experiments are under way, but Cirelli can’t predict the outcome.

“It could be that the changes are benign, temporary and reversible,” she says, “or there could be lasting consequences for brain maturation and functioning.”

Source: University of Wisconsin-Madison