The Great Mystery: Circadian Rhythms
Human alertness ebbs and flows along with other brain and body processes, a direct reflection of circadian rhythms. The hormone melatonin also contributes to the control of sleep. It is secreted in the darkness and inhibited by light. People need at...
The Great Mystery: Stages of Sleep
Sleep and dream research is part of the scientific study of consciousness. Both the body and brain are quite active during sleep. The frequencies and amplitudes of the EEG recorded during sleep reveal two primary types of sleep: REM sleep (rapid eye...
The Great Mystery: Functions of Sleep
Although the exact functions of sleep are unknown, researchers believe it serves a restorative function, providing a period when the body can heal and get ready for the next day. Some think that sleep is related to thermoregulation of the temperatur...
The Great Mystery: REM Sleep
During REM sleep eye movement and brainwaves are very active, but everything else seems paralyzed. Even the thermoregulatory system does not work during REM sleep. Newborn infants sleep about 16 hours a day, half of which is REM sleep. This leads re...