Unit 5: States of Consciousness

Introduction

Biological rhythms and sleep

1. While asleep we’re not totally “out of it” or totally unconscious. For instance, we respond to sounds.
2. People are built on an inborn 24-hour biological clock called the circadian rhythm. It regulates things like when we wake up, when we feel sleepy.
   1. Light in the morning hits our retinas which activates our suprachiasmatic nucleus (SCN) in our brain which cuts down the pineal gland’s production of melatonin, the sleep hormone.
   2. Being in bright light at night cuts down on sleep. As a result of lights in the modern world, many people get less sleep. Their bodies have taken on a 25-hour day (which throws off their night-day sleeping habits).
3. Sleep is not an on-off thing. There are 5 cycles built into sleep.
   1. Stage 1 – As you fall to sleep, an EEG registers slow alpha waves. You’re awake, but very relaxed, then slip into sleep. Breathing is slow and brain waves are irregular.
      1. Stage 1 sleep is brief.
      2. Alpha waves are very short in amplitude and tight in frequency.
      3. It may contain hallucinations, a sense of falling (ever jumped back awake?), or floating weightlessly.
   2. Stage 2 – This lasts about 20 minutes. An EEG shows sleep spindleswhich appear as very rapid, close flickers on the graph. An EEG may also show a K-complex which appears as a distinctly large and lazy flicker on the graph.
      1. Sleeptalking may occur herebut it also may occur at any other sleep stage.
   3. Stage 3 – This is a transitional stage between 2 and 4.
      1. An EEG shows some large, slow delta waves that look lazy on a graph.
   4. Stage 4 – This last about 30 minutes and is deep sleep.
      1. An EEG shows even more delta waves.
      2. This is where you’re “out of it” and may not hear loud noises like thunder.
      3. Children may wet the bed or sleepwalk.
   5. REM sleep – This is the 5th phase and the most important. This is where you brain is the most active. Oddly, whereas your body rests by doing little or nothing, your brain rests by working.
      1. After about an hour of going from stages 1, 2, 3, and 4, you leave what’s called NREM sleep. Then you start going back through the stages – 4, 3, 2 and into REM sleep.
      2. REM (rapid eye movement) first lasts about 10 minutes.
      3. An EEG shows that your brain waves are very similar to when you’re awake.
      4. Your pulse increases, your breathing becomes rapid and irregular. Your eyes shoot back and forth quickly.
      5. Your brain blocks messages to the motor cortex – you’re paralyzed.
      6. You can’t be easily awakened.
      7. REM sleep brings on dreams that are very realistic – emotional, storylike, and vivid.
   6. This 5-part sleep cycle goes through itself about every 90 minutes. Thus in a normal-length night, we go through about 4 sleep cycles.
4. Why do we sleep?
   1. People of different ages sleep different amounts of time. Children sleep longer, adults shorter.
   2. In the U.S., adults sleep just over 8 hours per day. Without lights or distractions, adults will sleep about 9 hours.
   3. Thus, we tend to have a sleep deficiency. There are good affects of enough sleep and bad affects of a deficiency…
      1. Getting enough sleep means we concentrate better, are in better moods, are less hungry/obese, have stronger immune systems, and have lower chances of accidents.
      2. Not getting enough sleep means the opposite of those things listed above. Other results of sleep deficiency are poor studying, less productivity, mistakes, crankiness, and feeling tired (imagine that!).
5. Sleep theories
   1. There are several theories to answer the question, “Why do we sleep?” They are…
      1. Sleep protects – This theory has the idea that we’re safer at night while asleep. We won’t bang into dangerous things in the dark.
      2. Sleep helps us recuperate – Brain activity creates toxins as a byproduct called “free radicals”. The idea is that sleep helps cleanse these from our brains by giving neurons a time to rest.
      3. Sleep makes for memories – After all of our daily activities, sleep enables our brain to sort things into their proper spots, so to speak. This helps with our memories later.
      4. Sleep can fuel creativity – Many great ideas come while asleep or dreaming. Or, many great ideas come just after a good night’s sleep.
      5. Sleep helps with growth – The pituitary gland, the growth gland, secretes a growth hormone while in deep sleep.
6. Sleep disorders
   1. Insomnia is the persistent inability to sleep or to fall asleep. It’s not the occasional inability to sleep.
      1. Insomnia can’t be “fixed” with alcohol or sleeping pills. These only reduce REM sleep and make the person feel even more sluggish the next day.
   2. Narcolepsy is a disorder where the person (or animal) simply falls asleep suddenly, out of the blue. It can be a problem because the person may fall asleep at a very bad or unsafe moment.
   3. Sleep apnea is a disorder where the person stops breathing at night, awakens, then breathes again.
      1. Most people don’t even know they’re waking, even though it can happen hundreds of times per night.
      2. Overweight men are especially prone to apnea.
      3. It can be treated by wearing a special mask.
   4. Night terrors attack children mostly. A child may sit up, walk, mumble, their pulse and breathing may double, and they may seem terrified.
      1. Night terrors are not nightmares. Terrors occur in stage 4 sleep. Nightmares occur during REM sleep and usually have a story or plotline to them.
      2. Children may also experience sleepwalking and sleeptalking.