When you feel sleepy some parts of your brain have already gone to sleep.
Contrary to conventional wisdom, the researchers say, there’s no control center in your brain that dictates when it’s time for you to drift off to dreamland. Instead, sleep creeps up on you as independent groups of brain cells become fatigued and switch into a sleep state even while you are still (mostly) awake. Eventually, a threshold number of groups switch and you doze off.
I had a busy weekend and I’m pretty sleepy today. I wonder what parts are asleep now? I would assume that parts that aren’t being used can be asleep and only wake up on demand or when their refresh state has been reached.
Sleepy brain
A related piece of work from UPenn:
Being deprived of sleep even for one night makes the brain unstable and prone to sudden shutdowns akin to a power failure — brief lapses that hover between sleep and wakefulness, researchers said on Tuesday.