Two studies identify a signaling pathway that contributes to the fish’s sleeplessness.

By examining brainwave patterns in a posterior cortical area, scientists can predict when people are dreaming.

Great frigatebirds can sleep while flying, researchers report.

People continue to hear and process words during light non-REM sleep, a study shows.

Autonomic nervous system activity during sleep may help explain variation in the extent to which the behavior aids memory consolidation, a study shows.

The first night people sleep in a new place, one of their brain hemispheres remains somewhat alert, a study shows.

An overview of the human sleep cycle

Poor slumber during pregnancy may have consequences beyond gestation.

Ideas abound for why some animal species sleep so much more than others, but definitive data are elusive.

Mapping the dreaming brain through neuroimaging and studies of brain damage