Sleep and Sleep Disorders Neural Control of Sleep

Sleep and Sleep Disorders

Neural Control of Sleep § Sleep and waking are different states of arousal. § Reticular activating system controls this. § Decrease in arousal is accompanied by less cortical activity.

Neural Control of Sleep § Bodily cycles (circadian rhythms) are controlled by part of the hypothalamus. § Pineal gland controls circulating levels of melatonin —more light, less melatonin.

Biological Clock Circadian Rhythms

Stages of Sleep REM Sleep

Rapid Eye Movement (REM)Sleep § Eyes move rapidly. § If awakened 90% report dreaming. § Paradoxical § Muscles relaxed. § Brain active. § Sometimes called active sleep. § Seems to be necessary. § If insufficient, amount per night increases.

Effects of REM Deprivation

Sleep Disorders

Sleep Apnea § Most who suffer from sleep apnea snore heavily. § All snorers do not have sleep apnea. § So what is it?

Sleep Apnea § Relaxation of sleep leads to blocking of airway. § Person awakes briefly, gasps, and falls back to sleep. § May happen 100 s of times per night.

Insomnia § Inadequate or poor quality sleep because of: § Difficulty falling asleep. § Waking up frequently during the night with difficulty returning to sleep. § Waking too early in the morning. § Unrefreshing sleep.

Insomnia § More common for: § § § Elderly Females Those who are depressed. § Causes: § § § Stress Environmental noise Extreme temperatures Change in the surrounding environment Sleep-wake schedule problems, e. g. , shift work, jet lag. Side effects of medication.

Insomnia § Contributing factors: § Expecting to have difficulty sleeping. § Large amounts of caffeine. § Drinking alcohol before bedtime. § Smoking cigarettes before bedtime. § Excessive napping in the afternoon or evening. § Irregular, or continually changing sleep-wake schedules.

Less Common Sleep Disorders § Narcolepsy § Sleep disorder characterized by sudden bouts of irrepressible sleep. § Individual may fall to ground in sound sleep. § Can be dangerous if not controlled. § Regular hours and sufficient sleep. § Drugs § Cataplexy § Individual experiences sudden muscle paralysis as in REM sleep while they are awake. § Will collapse.

Sleep Walking § More common in children. § Usually outgrown by the age of 15. § Occurs during deepest sleep rather than REM sleep.

Night Terrors

Night Terrors § Also occurs during deepest, Stage 4 sleep. § Most common in children between 4 – 7 years of age. § Child wakes crying as if in terror but seems as if not really awake. No response to visual stimuli or questions. § May, or may not report a scary dream when fully awake.

What is Sleep For? § It seems to be restorative: § Restores glycogen stores and stengthens the immune system. § Bodily repair—extremely active people sleep more. § Bodily rhythms may have evolved to ensure quiet periods during time when most predators for the species are about. § Consolidation of learning: § Lack of sleep interferes with memory storage.