Sleep as a State of Consciousness

1. Sleep as a State of Consciousness Even when you are deeply asleep, your perceptual window is not completely shut What is our evidence of this?

2. Biological Rhythms and Sleep • Circadian Rhythm • 24 hour cycle of day and night through our biological clock • Body temp rises, peaks, dips, and drops • Thinking is sharpest at peak • Why is pulling an all-nighter a TERRIBLE idea?

3. So what’s going on here… • Let’s take a second to go back to the eye/brain relationship 1. Bright light tweaks circadian clock by activating light sensitive retinal proteins 2. Proteins control circadian clock triggering suprachiasmatic nucleus (SCN) in the ____________ 3. SCN causes brain’s pineal gland to decrease production of melatonin (sleep-inducing hormone) in mornings and increase in evenings

4. What has caused us to stay up later and force ourselves awake in the morning?

5. Sleep Stages • Considered different state of consciousness because different parts of brain’s cortex stop communicating • Still-active sleeping brain has its own biological rhythm • Which brain scan is used most in sleep studies?

6. Sleep • Need for sleep varies with individuals • 20 hours for infants • 6 hours for adults in their 70’s

7. Stage 0: A person is relaxed with eyes closed • EEG shows alpha waves • “falling asleep” called hypnagogic state • Lucid dreaming • “waking” period is called hypnopompic state • just ten more minutes…

8. Quiet Sleep: NREM sleep • Stage 1 lasts from 30 secs to 10 min • Characterized by sensory images and slow rolling eye movements • Appearance of theta waves on EEG • May experience hallucinations • Sensation of falling • Most alien abductions happen here

9. Quiet Sleep • Stage 2 lasts 20 minutes • theta waves, sleep spindles, and K-complexes on EEG • Sleep spindles: bursts of rapid, rhythmic brain wave activity • Sleep talking occurs most here • You are now full on asleep

10. Quiet Sleep • Stage 3 • Transition to stage 4 • Recognized by the beginning of delta waves on EEG

11. Quiet Sleep • Stage 4 • Deep sleep • Lasts 30 min, recognized by 20-50% delta waves in EEG **AMOUNT OF TIME SPENT ON STAGES 3 AND 4 VARIES AS NIGHT PROGRESSES**

12. Active Sleep: REM • Nearly all dreams occur in REM • Dreams are more vivid and story-like than in earlier stages • REM increases during the night • Less than a minute to over an hour • 25% of the night’s sleep • Causes atonia which is temporary paralysis of the body • Brain is active while body shows loss of muscle tone

13. REM Sleep

14. During REM Sleep • Heart rate rises • Breathing becomes rapid and irregular • Eyes dart around • Genitals become aroused • Erections/vaginal lubrication and clitoral engorgement (not dependent on sexual nature of dream) • Men’s erection upon waking stems from the night’s last REM • Typical 25 year old male erections happen for half the night

15. How are you “active” yet not… • Brain’s motor cortex is running… • Brainstem blocks the messages • Muscles relaxed (essentially paralyzed) • REM is called paradoxal sleep • Internally aroused, externally calm • So, how is it that arousal happens when we sleep?

16. Sleep Cycle • Repeats about every 90 minutes • Night progresses, deep stage 4 gets briefer and disappears • REM and stage 2 get longer • By morning, 20 to 25% has been REM • Everyone dreams, we don’t remember most of what we dream • What are the dreams called that we most remember?

17. Why do we sleep? • Without sleep our bodies deteriorate • Functionality/productivity • Aging • Weight gain and metabolism • Suppress immune cells (infections/cancer) • Memory impairment

18. Wait… hold up… you said weight gain? • Sleep deprivations increases hunger-arousing hormone – gherlin – and decreases hunger-suppressing hormone – leptin • Increases appetite and eating • Also increases stress hormone – cortisol

20. Sleep Disorders • Insomnia • Narcolepsy http://www.youtube.com/watch?v=-zVCYdrw-1o • Apnea • Parasomnias • SIDS • Jet lag • Sleepwalking (Somnambulism) • Bruxism

21. Dreams • Theoretically based • Freud and driven unconscious

22. Freud’s wish-fulfillment • Psychic safety valve • Safe place to express unacceptable feelings • Hidden meanings • On The Interpretation of Dreams

23. Information-processing • Dreams help sort the day’s events and consolidate our memories • That story about the place with the guy that did the stuff… oh crap I lost it…

24. Physiological function • Brain stimulation during REM = develop and preserve neural pathways

25. Activation-synthesis • REM triggers neural activity to evoke random memories which our brain weaves into stories • Ever had a dream about the first house you lived in or a childhood occurrence?

26. Cognitive development • Dreams reflect individual’s knowledge and understanding of the world around them • Some take it WAY to seriously

27. Hypnosis

28. Can anyone experience hypnosis? • Yes! • Well, sort of – it’s called suggestion

29. Can hypnosis be theraputic? • Maybe kinda sorta not really but in only in some cases… • Posthypnotic suggestion has been found to alleviate headaches, asthma, stress-related disorders • How about pain? • Hmmmm that’s up for debate.

30. How does it work? • Hypnosis is a divided consciousness • According to some or most or any or none • Dissociation: a split in consciousness which allows some thoughts and behaviors to occur simultaneously with others • Remember selective attention?