The brain of a sleeping person wakes up more than a hundred times a night, and this is normal.

Frequent awakenings of the brain during sleep is absolutely normal. This process is important for memory - short awakenings reboot the brain so that it can retain all memories. It takes about 30 seconds from the peak of one wave of norepinephrine to another. The deeper the low point, the stronger the sleep and the higher the next peak, and hence the degree of awakening. These conclusions were reached by scientists from the University of Copenhagen in the course of experiments on mice. The researchers believe the results of the work will be useful in the creation of new antidepressants.