Forgoing sleep to watch one more episode of the latest show, to read one more chapter of a thrilling book, or even to pull an all-nighter, is not uncommon. But sleep deprivation can catch up to people ...

I llusions are everywhere. For example, the moon appears larger when it rests on the horizon than when it is hanging in the sky. Other visual tricks occur when a person perceives an object in an image ...

Certain brain cells are responsible for coordinating smooth, controlled movements of the body. But when those cells are constantly overactivated for weeks on end, they degenerate and ultimately die.