Sleep research. Time-lapse photograph of the movements of a man asleep over a period of time. Sleep is a state of lowered consciousness and reduced metabolism which takes up about one third of a person's life. Two distinct types of sleep have been recognised: REM (rapid eye movement) and NREM (nonrapid eye movement). The latter,which accounts for the major part of sleep,starts with drowsiness; brain waves become increasingly deeper and slower until brain activity and metabolism fall to their lowest level. In REM sleep,the brain suddenly becomes more electrically active,its blood flow increases,the eyes move rapidly and dreaming occurs | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Spagna, Ted |
Taille de l’image : | 3435 px × 2407 px |
Model Release : | Le droit n'est pas encore disponible. Merci de nous contacter avant utilisation. |
Property Release : | Non requis |
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