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?

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?

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

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

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?

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

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…

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

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

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

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**

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

REM Sleep

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

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?

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?

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

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

Sleep Disorders Insomnia Narcolepsy Apnea Parasomnias –SIDS –Jet lag –Sleepwalking (Somnambulism) –Bruxism

Dreams Theoretically based Freud and driven unconscious

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

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…

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

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?

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

Hypnosis

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

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.

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?