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The Stages of Sleep. Polysomnography measures patterns in: Electroencephalogram (EEG) ~ brain waves Electrooculography (EOG) ~ eye movement Electromyography (EMG) ~ muscle tone. Most commonly electrodes are placed at C3, C4, O1 and O2. NonREM sleep:. REM Sleep ( R apid E ye M ovement):.
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The Stages of Sleep • Polysomnography measures patterns in: • Electroencephalogram (EEG) ~ brain waves • Electrooculography (EOG) ~ eye movement • Electromyography (EMG) ~ muscle tone Most commonly electrodes are placed at C3, C4, O1 and O2
Biological Rhythms: Cycles of Sleep Delayed Sleep Phase Syndrome
Animals and Sleep: • Human sleep cycle is 90 min., cat’s 25 min., rats 11 min. The cycle length is largest in species with large brains. • Almost all mammals and birds have REM sleep, meaning they dream • Although reptiles also have periods of REM sleep, they do not show similar forms of brain activity that would indicate dreaming. • The amount of REM sleep an animal gets seems to be related to its safety in its environment. The more danger for the animal, the less REM sleep. • The amount of REM sleep is also related to how developed the animal is at birth. Animals born fairly mature, such as sheep have less REM sleep than animals that continue to grow and develop more after they are born, such as humans. • Australian echidna (egg-laying mammal) and also dolphins and porpoise do not have REM sleep. • - Dolphins are “conscious breathers” which means that they are never completely asleep. EEGs show that only half of their brain is asleep at a time.