As fatigue grows, electrical activity mounts
Sleep deprivation makes the brain groggy, but as waking hours mount nerve cells grow increasingly jumpy, a new study shows.
This amped-up state may explain why seizures and hallucinations can accompany an all-nighter. More generally, the results help clarify what goes wrong in a brain deprived of shut-eye.
“It’s an important finding,” says neuroscientist Christopher Colwell of UCLA. “Sleep deprivation is an area of huge interest because most of us do not get enough sleep.”
By subjecting six people to a night of sleep deprivation and measuring their brain responses, Marcello Massimini of the University of Milan and colleagues found that people’s brains become more reactive as hours awake accumulate.
To look for signs of altered brain function, the team delivered magnetic pulses to the participants’ skulls that kicked off an electrical response in the nerve cells (an effect like the noise made when a hamme