What is consciousness?
What is cognitive neuroscience?
Conscious and the Nonconscious Mind
Levels of Nonconscious
Preconscious - easily cued
Unconscious - levls of processing without awareness
Circadian Rhythms – biological clock (about 24 hours); regular body rhythms
- Regulated by hormones / Light resets biological clock
o Darkness stimulates secretion of melatonin by pineal gland, which causes slowing of biological activity
o Can buy melatonin to induce sleep
Sleep stages
Measure brain activity during sleep with EEG.
Awake and relaxed – alpha waves
Sleep – low amplitude brain waves; slowed breathing, 90 minute cycles
Stage 1 – (5 min) hypnogogic state (floating, falling), low amplitude EEG, easily awakened
Stage 2 – (20 min) sleep spindles, clearly asleep, sleeptalking may occur here
Stage 3 – (transitional) begin delta waves (large and slow); slow-wave sleep
Stage 4 – (shorter as night progresses) delta waves, sleepwalking, deep sleep
Progress backwards through stages 3, then 2, then REM sleep
REM sleep – (longer as night progresses) EEG like alpha waves, heart rate increases, breathing rapid and irregular, eyes move back and forth, genital arousal, brainstem blocks messages from motor cortex, paralyzed, dream here -
Why we sleep?
1. Evolutionary psychology – sleep protects; better to be safe in cave than vulnerable in dark
2. Physiological psychology – sleep frees up energy to restore body and brain and allow for growth
Sleep Disorders
Insomnia – problems falling or staying asleep
- People with insomnia tend to overestimate their lack of sleepSleeping pills and alcohol reduce REM sleep
Narcolepsy – uncontrollable sleep attacks
- 1 in 2000 people
- triggered by strong emotions
- lapse into REM sleep with accompany muscular paralysis
Sleep apnea – stop breathing during sleep / in babies SID
- 1 in 25 people (mostly overweight men)
- Can repeat up to 400 times per night!
- Wake up snorting so partner often complains of loud snoring
- Most don’t remember awakening
Night terrors – high arousal and physiological symptoms of terror during stage 4 sleep
- Heart rate and breathing rate double
Why do we dream?
- Freud’s theory – (wish-fulfillment) dreams are time for the id to express itself; they reflect our innermost desires that are too threatening to express directly. Thus, dreams have manifest content (the literal narrative) and latent content (the underlying meaning)
- Information processing – dreams facilitate memory by rehearsing important events; dreams are bizarre because we incorporate other memories into them
- Activation-synthesis theory – the brain periodic “exercises” during the night by sending random electrical impulses; dreams are the brain’s interpretation of its own activity
We need REM sleep – if prevented from it, we have experience REM rebound (increase in REM sleep) later.
Hypnosis
Hypnosis – an interaction in which one person suggests to another that certain perceptions, feelings, etc with occur spontaneously.
- The ability to turn attention inward, relax, and imagine
- Posthynoptic amnesia – inability to remember things that happened during hypnotic state (controversial)
- Evidence suggests that people cannot do anything under hypnosis that they cannot do normally; it seems to be a state of increased motivation
- Susceptibility to hypnosis
- Highly susceptible people tend to have rich fantasy lives
- More likely to be responsive if you believe it
- Enhancing Recall of Forgotten Events
- Not true; a few rare instances, but not confirmed
- Hypnotically refreshed memories combine fact and fiction; susceptible to false memory suggestions
- Acting Against their Will
Alleviate pain?
- YES
- 10% can become so deeply hypnotized they can undergo major surgery without anesthesia
- 50% experience some pain relief from hypnosis.
- How? Selective attention or actually dissociating pain from conscious awareness?
Theories of Hypnosis
- Social-influence theory – hypnosis an extension of everyday social behavior
- Divided-consciousness theory – hypnosis is a dissociation between our conscious awareness and our automatic behaviors
Drugs and Consciousness
Psychoactive drugs – chemical that alters perceptions and mood
- Tolerance – user requires a larger amount to get same effects
- Withdrawal – user experiences discomfort when discontinuing use
- Physical – physical pain
- Psychological – cravings
Psychoactive Drugs
Depressants – calm neural activity and slow body function
Alcohol
- 1. decreases inhibitions – people are more aggressive and more loving
- 2. Relaxes sympathetic nervous system (reactions slow speech slurred, performance deteriorates)
- 3. Disrupts processing of information into long-term memory
- 4. suppresses REM sleep
- 5. People who believe they have ingested alcohol exhibit symptoms of being drunk
- TYPES OF DRUGS - SEE TEXT LIST