Consciousness Section 2 Sleep and Dreams Consciousness Section 2

Why do we sleep? Different theories… It recharges our batteries – we recover from exhaustion and stress It is a primitive form of hibernation (we are conserving energy) It is adaptive (sleep kept humans safe at night when they would be more likely to be harmed by animals with better night vision

Sleep State of altered consciousness with patterns of brain activity and inactivity Consciousness – state of awareness, including feelings, sensations, ideas, and perceptions Altered consciousness means that there are different levels of awareness. Electroencephalograph – used to study the electrical activity of the brain during sleep

Stages of Sleep Physiological characteristics Temperature decreases, heart rate drops, breathing is slow and even Brain shows alpha waves which indicate an absence of concentration

Stages cont. Early stages Stage 1: ~10 minutes Stage 2: ~ 30 minutes Pulse rate slows more and your muscles relax Breathing is uneven Brain waves are irregular (theta waves) Stage 2: ~ 30 minutes Eyes roll from side to side Change in brain waves Stage 3: Deeper level Brain waves are large in amplitude and not as frequent

Stages cont. Later stages Stage IV Deepest sleep Difficult to awaken; if awaken by a loud noise or sudden movement, you may be disoriented Talking out, sleep-walking, bed-wetting occur during this stage (you do not remember these) Must have deep sleep for physical and psychological functioning REM sleep (active sleep) – rapid eye movement; ~15-45 minutes Pulse rate and breathing are more irregular Adrenal and sex hormones increase Small muscles may twitch; large muscles are “paralyzed” Brain waves are like those of someone who is fully awake Most dreams happen Cycle repeats approximately every 90 minutes

How much sleep do we need? Newborns – 16 hours 7-12 years old – 10-11 hours Teens – 9 Adults – 8 Circadian rhythm – biological clock genetically programmed to regulate activity over 24 hour time period Get hungry or sleepy at the same of day; go to the bathroom at the same time each day Does not control sleep cycles

Sleep Disorders Insomnia Sleep apnea Inability to get enough sleep at night in order to feel rested Prolonged Many causes: Anxiety Depression Alcohol/drug use Sleep apnea Person has trouble breathing during sleep; breathing passages are blocked Ends when low levels of oxygen or high levels of CO2 triggers breathing reflexes Symptom – snoring that ends abruptly with a sudden movement of the body Caused by a physical problem such as enlarged tonsils, infections in the throat or ears, or obesity

Sleep Disorders cont. Narcolepsy Nightmares and Night Terrors Permanent and overwhelming feeling of sleepiness or fatigue Person may fall asleep suddenly May have hallucinations or unusual sleep patterns Nightmares and Night Terrors Nightmares occur during REM; person will awaken and remember the dream Night terrors – occur during stage IV; last 5-20 minutes; may involve screaming, sweating, confusion, and a rapid heart rate; person will not remember the night terror Sleepwalking and Sleep talking Sleepwalking – person is partially but not completely awake; person will walk or do other things without any recollection of doing so Occurs mostly with children Neither dangerous or necessary to awaken sleepwalkers Talking – words or phrases Can occur during REM or NonREM Usually do not remember it

Dreams Dreams at first are a result of the days activity As sleep progresses, dreams are longer, more vivid, and dramatic The last is usually the longest and the one a person remembers Content Usually dull; however we remember the ones that are more interesting Usually occur in a common setting (work, home, school) A large percentage of emotions are negative – anxiety, anger, etc. Dream interpretation Sigmund Freud – dreams contain clues to thoughts the person is afraid to acknowledge; believed they contained hidden messages Some cultures believe that during dreams people can interact with people who have died Some think that dreams allow a person to review and address some of the problems of the day Daydreams Require a low level of awareness Involve fantasizing or idle thinking May allow us to control our creativity and our emotions