There is a tiny region of the brain – called the suprachiasmatic (soop-ra KYE-as-matic) nucleus, or SCN – made of only a few thousand neurons. This two-sided control center in the hypothalamus regulates circadian rhythm. It does this through the signals it gets from daylight. It tells us when to wake up, and when to go to sleep (unless you’re in college and then all bets are off).
Put more plainly, the SCN is our internal clock. Light controls our lives, and if you don’t play by its rules you can get very sick. READ MORE