circadian rhythm cyclical changes that occur on a roughly 24 hour basis in many biological pro cesses biological clock term for the suprachiasmatic nucleus SCN in the hypothalamus that s respon sible for controlling our levels of alertness disruption of biological clock ex jet lag flight to a different country misconception that elderly need less sleep 1951 a discovery in Nathaniel Kleitman s sleep laboratory in the University of Chicago changed how we think about sleep and dreaming Eugene Aserinsky Kleitman s graduate student monitored Armond s eye Kleitman s son sleep electroencephalogram measured electrical charges in the brain They confirmed rapid eye movements REM where dreams were reported and non REM sleep where dreams were less likely reported but research later shows that dreams occur in this stage as well Stages of Sleep Stage 1 light stage of lseep lasts five to ten minutes brain activity powers down by 50 percent produces theta waves occurs 4 to 7 times per second hypnagogic imagery scrambled bizarre and dreamlike images that flit in and out of conscious ness myoclonic jerks sudden jerks Stage 2 Sleep brain waves slow down even more sleep spindles sudden bursts of electrical activity 65 of our sleep in this stage k complexes occasional sharply rising and falling waves Stage 3 and 4 occurs after 10 to 30 minutes delta waves occur slow as one to two cycles a second in EEG delta waves appear more than half of the time in stage 4 alcohol suppresses delta sleep Stage 5 REM SLEEP after 15 to 30 minutes increased heart rate and blood pressure we dream more in REM much more emotional when humans are deprived of REM sleep we go through REM rebound much more intense dreams MEMA middle ear muscle activity in which the muscles of our middle ears become active al most as though they re assisting us to hear sounds in the dream paradoxical sleep b c the brain is active at the same time that the body is inactive REM behavior disorder RBD we act out our dreams Lucid Dreaming dreaming knowing that you were dreaming Opens the possibility of control ling our dreams Disorders of Sleep Insomnia difficulty falling and staying asleep people that suffer depression pain or a variety of medical conditions report high rates of insomnia Ambien pill for treating insomnia some people are reported to eat drive and walk while using this drug Narcolepsy dramatic disorder in where people experience episodes of sudden sleep lasting any where from a few seconds to several minutes disorder characterized by the rapid and often un expected onset of sleep can experience cataplexy a complete loss of muscle tone Sleep Apnea disorder caused by a blockage of the airway during sleep resulting in daytime fa tigue associated with being overweight Night terrors screaming perspiring and confusion followed by a return to a deep sleep nor mally occurs in children Sleepwalking walking while fully asleep dreams are involved in a b tual reality model of the world processing emotional memories integrating new experiences with established memories to make sense of and create a vir c d e learning new strategies and ways of doing things stimulating threatening events so we can better cope with them in everyday life reorganizing and consolidating memories Major Theories of Dreams Freud s Dream Protection theory Book The Interpretation of Dreams 1900 described dreams as the guardians of sleep dream work disguises and contains the sexual and aggressive impulses by transforming them into symbols that represent wishful fulfillment According to Freud dreams don t surrender their meanings easily they need interpretation manifest content details of the dream itslef wish fulfillment is the meaning of each and every dream which is impossible for people with brain injury to have latent content the hidden meaning of a dream Activation Synthesis Theory developed by Alan Hobson and Robert McCarley proposess that drams reflect brain activation in sleep rather than repressed unconscious wish that dreams refelc the activated brain s attempt to make sense of random and internally gener ated neural signals during REM sleep REM is turned on by surges of the neurotransmitter acetlycholine activated pons send INCOMPLETE signals to the lateral geniculate nucleus of the thalamus basically that dreams reflect inputs from brain activation originating in the pons which the forebrain then attempts to weave into a story Dreaming and the Forebrain Mark Solms surveyed patients with brain dmage He determined that the deep frontal white matter that connects different parts of the cortex to the lower brain the parietal lobes can lead to a complete loss of dreaming Damage to the forebrain can eliminate dreaming completely even when the brain stem is fine According to Solms dreams are driven largely by motivational and emotional control centers in the forebrain Neurocognitive Theory scientists supporting this theory say that explaining dreams in terms of neurotransmitters random nerve impulses doesnt tell the full story complex dreams are cognitive achievements that parallel the gradual development of visual imagination and other advanced cognitive abilities Dream content is stable over long periods of time Scientists agree that 1 2 acetylcholine turns on REM Sleep the forebrain plays an important role in dreams Hallucinations are realistic perceptual experiences in the absence of any external stimuli in this the visual cortext becomes active misconception is that hallucinations occurs in psychologically disturbed individuals visual hallucinations can be brought upon by lack of oxygen and sensory deprivation Out of Body and Near Death Experiences floating outside your body calmly observing yourself People who are prone to OBEs frequently report other unusual experiences including vivid fantasies lucid dreams hallucinations perceptual dis tortions and strange body sensations in everyday life people also experience this when they are medicated this is a common frequent thing remind us of the human brains ability to integreate sensory information from different path ways into a unified experience Near Death Experiences reported by people who ve nearly died or thought they were going to die experince passing through a dark tunnel experiencing a bright light the light seeing our lives pass before our eyes and meeting spriritual beings long dead relatives all before com ing back to the body Deja Vu Experiences experience of been there done that an excess in
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