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.