dream, mental activity associated with the rapid-eye-movement (REM) period of sleep. Itis commonly made up of a number of visual images, scenes or thoughts expressed in termsof seeing rather than in those of the other senses or in words. Electroencephalographstudies, measuring the electrical activity of the brain during REM sleep, have shown thatyoung adults dream for 1 1/2 to 2 hours of every 8-hour period of sleep. Infants spend anaverage of 50% of their sleep in the REM phase (they are believed to dream more oftenthan adults) a figure which decreases steadily with age. During dreams, blood pressure andheart rate increase, and breathing is quickened, but the body is otherwise immobile.Studies have shown that sleepers deprived of dream-sleep are likely to become irritableand lose coordination skills. Unusually frightening dreams are called nightmares, anddaydreams are constructed fantasies that occur while the individual is awake. Studies havedemonstrated the existence of lucid dreaming, where the individual is aware that he isdreaming and has a degree of control over his dream. Sigmund , in his pioneering work The Interpretation of Dreams (1900, tr. 1913), was oneof the first to emphasize dreams as keys to the unconscious. He distinguished the manifestcontent of dreams—the dream as it is recalled by the individual—from the latent contentor the meaning of the dream, which Freud saw in terms of wish fulfillment. C. G. held thatdreams function to reveal the unconscious mind, anticipate future events, and giveexpression to neglected areas of the dreamer's personality. Another theory, which PETscan studies appear to support, suggests that dreams are a result of electrical energy thatstimulates memories located in various regions of the brain....
