Tired brain defaults differently
Finding may explain why sleep-deprived people have trouble on mental tasks
SAN FRANCISCO — Sleep-deprived people make mistakes. New research suggests that a tired brain may turn on the equivalent of an internal screen saver instead of concentrating on mental tasks, which may explain those blunders.
Ninad Gujar of the University of California, Berkeley and colleagues presented evidence March 22 at the annual meeting of the Cognitive Neuroscience Society that sleep deprivation affects the brain’s default network.
Scientists describe the default network as the parts of the brain that deactivate when a person is doing a specific mental task, such as having a conversation, reading or memorizing a list of words, or solving a math problem. The network is active, though, when people are ruminating, daydreaming, recalling the past or when the mind wanders. Researchers still don’t fully understand how the network works and how it affects cognition.
Gujar wanted to find out if sleep deprivation affects the default network. His team tested 28 young adults; half got a normal amount of sleep and half were kept awake for 35 hours before testing. The volunteers did memory tests while in an fMRI scanner. Every time the volunteers saw a particular picture, they were supposed to punch a button.