Sleep Deprivation And Disruption Notes

Sleep Disruption and Deprivation Melatonin rhythms One of the actions of melatonin in seasonally-breeding animals is affecting the reproductive axis and can dramatically control testicular size. In an animal with short photoperiod, the animal's testes are small, whilst in a long photoperiod the testes are considerably larger. This means that in early summer, the male would be much better equipped to breed than in winter time. Human sleep cycles Human sleep has an intrinsic short 90 minute period. It was once thought to be a passive state with no brain activity. This is false- the brain is very active and there are distinct patterns of electrical activity, associated with 90 minute cycles correlating to different stages of sleep. There are two stages of sleep that have been described - REM and non-REM. Non-REM has 4 distinct stages associated with particular patterns of electrical activity REM has its own pattern of electrical activity. Mostly sleep has 5 cycles of 90 minute bouts and then REM sleep which can be measured by using macroelectrodes whilst sleeping. EMC - skin and muscle activity, EEG - brain activity EOG ocular activity. EEG pattern for wakefulness compared with REM sleep is very similar. Awake - fast low amplitude activity, like in REM sleep. During non-REM is high amplitude low frequency oscillations. REM sleep also been called paradoxical sleep for this reason- paradoxically resembles that of waking. Thought patterns o Awake - logical progressive thought, o non-REM may have logical thoughts but more perseverative, o REM illogical thoughts Movement - o wake continuous voluntary, o non-REM, slightly repetitive occurring involuntarily o REM sleep can dream abut running but the movements are not acted out as muscle control is inhibited by other processes in the brain. Sense and perceive stimuli during sleep - waking them up immediately at different stages to ascertain perception. o Awake - externally generated, vivid; o non-REM dull or absent, o REM internally generated stimuli. Drowsiness- more definite pattern than wakefulness, activity is known as alpha-waves. Stage 1 of non-REM is characterised by theta- waves Stage 2 non-REM sleep spindles and k complexes are seen Stage 3 high amplitude, low frequency oscillations know as delta waves. In REM sleep, remarkably similar to waking patterns. 

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