Immunology

By Sally Robertson BSc

Sleep could play a major role in our ability to form long-term memories, suggest study findings.

By examining neural activity in the brains of mice, researchers have been able to observe the active consolidation of memories that occurs in these creatures while they are asleep.

“We show sleep really helps to make connections and that in sleep, the brain is not quiet, it is replaying what happened during the day,” says lead author Wen-Biao Gan from New York University.

For the study, Gan and colleagues tagged nerve cells in the brains of mice. The animals then ran on a rotating rod before being allowed to sleep. Some of the mice were allowed to sleep for an uninterrupted period, while others were handled intermittently to disrupt the quality of their sleep.

As reported in the journal Science, the mice that slept uninterrupted showed stronger signs of neural connections being formed during the initial, non-REM phase of sleep. During the REM phase, nerve connections that were made while the mice ran were reactivated. However, when the this reactivation was blocked, no further new connections were made.

The researchers say these findings suggest that the formation of long-term memory is a two-part process, in which sleep is a vital component.

Further research is required to assess the relevance of these findings to humans, says Gan, who hopes that some of the same principles apply.