It’s hard to tell how much a mouse remembers, but by peering at the activity of nerve cells in animals’ brains while they sleep, researchers have found some clues. That’s how Wen-Biao Gan, a neuroscientist and physiologist at New York University, learned some interesting things about what happens when mice snooze.
By tagging nerves cells in their brains, Gan and his colleagues report in the journal Science that sleep is actually a very active time for the brain, in which connections between buzzing nerve cells are made in order to consolidate memories. The researchers had mice run on a rotating and accelerating rod, then allowed them to sleep. Some of the mice got to slumber undisturbed, while others were handled to keep them from getting quality sleep. The animals who slept undisturbed showed signs of new neural connections forming during just the first phases of sleep, known as non REM sleep.
“My feeling is that sleep is important to the process of forming long term memory,” says Gan. During REM, not only are the same nerve connections that the mice made while they ran reactivated, but new connections were also made. When he blocked the reactivation of nerves, no new connections were made, suggesting that learning, or making long term memories, is a two part process in which sleep plays an important role.
How applicable are these findings to helping people? Hopefully some of same principles apply, says Gan, although more studies will be needed to confirm that. So don’t underestimate how much work your brain is doing while you catch some z’s. Most of what you remember could be thanks to getting a good night’s sleep.