For those who want a better and more restful sleep, we have this enlightening "Time" article on "Bedtime":
During sleep, the brain cleans up and consolidates memories. Sleep researchers explore what happens. A night in the brain. By Tobias Hürter
21.00 watch (tiredness)
The night starts with the change of light. Photosensitive cells in the retina of the eye report to the brain: bedtime! The cells come from the primeval times of evolution and are not for the sake of vision, they can also be intact in the blind. They register the red of the sunset. Blue screen light confuses them and impedes falling asleep.
At the signal of the eyes, the pineal gland releases melatonin deep in the brain, the hormone of the night. It makes you sleepy and sexually sluggish and prepares the body for sleep. A complicated cascade of proteins and chemical messengers gets going. Some of these substances deepen sleep. Some wake up. Others block the awake-makers. Caffeine blocks the blockers.
23.00 clock (falling asleep)
The effect of melatonin is stronger, the thoughts flow more slowly, the reaction times are longer, the muscle tension decreases. One tends to shiver, the body temperature is half a degree Celsius below their average value. With the temperature also the mood decreases. Melatonin makes you melancholy, so the night sometimes seems grim.
Light off, the head sinks into the pillow. The brain is now busy with itself. As soon as the eyes are closed, the fast brainwave waves, which prevail in the wake, ebb. Instead, the more leisurely alpha waves that signal to all brain areas that it's time to relax. However, not all areas hear at the same speed. The thalamus, an evolutionary ancient structure in the middle of the brain, dawns about nine minutes earlier than the cerebral cortex.
»If this article is interesting to you, read on directly in the source: Sleep Research: The Dramaturgy of the Night | TIME ONLINE