States of Consciousness

• Sleep and Dreams

• Hypnosis

• Drugs and Consciousness

• Near-Death Experiences

• Meditation

States of Consciousness

Forms of Consciousness• Spontaneous: daydreaming, drowsiness, dreaming

• Physiologically Induced: hallucinations, pain, hunger, lack of oxygen

• Psychologically induced: sensory deprivation, hypnosis, meditation

Selective Attention

Our conscious awareness processes only a small part of all that we experience. We

intuitively make use of the information we are not consciously aware of.

Inattentional Blindness

Simons & Chabris (1999) Univ. Illinois

Change Blindness

Change blindness is a form of inattentional blindness in which two-thirds of individuals giving

directions failed to notice a change in the individual asking for directions.

© 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons.

Sleep & Dreams

Biological Rhythms and SleepCircadian Rhythms: “About a Day” – our biological clock

Body temperature, sleep/wake cycle, heart rate, hormone levels, neurotransmitter release

Light suprachiasmatic nucleus decreases pineal melatonin No Light SCN increases pineal melatonin

Measuring Sleep

Measuring Sleep

Sleep Cycle: each 90 minutes, we pass through a cycle of five distinct sleep stages.

Sleep Stages

Hank Morgan/ Rainbow

Eye

Muscle

Brain

Measuring Sleep

Sleep Stages

Awake, eyes closed

Sleep: Stage 1

Sleep: Stage 2

Sleep: Stage 3/4

Sleep: REM

Brain (EEG) Stage

Awake

nonREM

REM

Stages of Sleep

Rapid Eye Movement Sleepnon-Rapid Eye Movement Sleep

Awake REM nonREM

EEG

EMG

EOG

REM Sleep

• “Awake” EEG• Muscular (skeletal) paralysis• Eye movement• Dreaming is common

90-Minute Sleep Cycles

Time asleep Stage 4 REM

AccidentsSleep Accidents

Sleep Theories

• Protection: avoid danger• Conserve energy• Recovery/Repair: restore and repair brain tissue.

(exercise, sleep)• Memory: build memories.

(sleep, memory)• Growth: growth hormone (GH) released.

(Older people: growth hormone, sleep)

Sleep’s role in recovery/repair

Growth hormone is released during the deep stages of sleep.

deep sleep

Sleep onset

Recovery/RepairLonger sleep time improves the function of the immune system and helps fight off infection

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immune system cells

Less sleep = fewer immune system cells

Neuronal Energy Production• In wake promoting areas of the brain, ATP (the

energy currency of brain cells) increases during the first few hours of sleep.

• This surge in ATP increases with deeper stages of sleep.

1/3 of life asleep!

Sleep Deprivation

•Fatigue and subsequent death

•Impaired concentration

•Emotional irritability

•Depressed immune system

•Greater vulnerability

Why Sleep?

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Sleep loss impairs social interactions

Less sleep leads to more arguments

More sleep leads to fewer arguments

Sleep habits influencephysical health

Short sleep times (≤7 hrs per night) are associated with increased:

• Appetite• Body mass (obesity)• Risk of diabetes• Risk of cancer• Incidence of cardiovascular disease

Why Sleep?

Sleep is essential for life.

World record for no sleep = 11-12 days (264-288 hours) 18 days?

Hallucinations, vision/speech/memory problems but with full recovery.

Animal Sleep

20 hr 18 hr 16 hr

13 hr 4 hr 3 hr

Unusual Animal Sleep

New calves/mothers:No sleep for 3 weeks!

Unusual Animal Sleep

Brain Mechanisms

AWAKE

Brain stem(reticular activating system)(locus coeruleus)(raphe n.)

AwakeEEG desyn

Stimulate

ACh5-HTNEHistamineHypocretin

Brain Mechanisms

Non-REM

SleepEEG Syn

Brain Mechanisms

REM

SleepEEG desynNo muscle

Brain Mechanisms

Cerebral Cortex

Thalamus

Brainstem

Discover Sleep

Dream Journal

REM “Detective”

• Insomnia: Persistent inability to fall asleep. (30-40%)

• Narcolepsy: Overpowering urge to fall asleep that may occur while talking or standing up.

• Sleep apnea: Failure to breathe when asleep. (2-3%)

• Night terrors: Sudden arousal from sleep, intense fear, rapid heart rate, sweating, Stage 4 disorder.

• Sleepwalking: Stage 4 disorder, usually harmless, no recall (1-15%)

• Sleeptalking: Stage 1-4 disorder, runs in families

• Restless Legs Syndrome: unusual feelings at bedtime (10%)

Sleep Disorders

Why Dream?• Wish Fulfillment (Freud): safety valve to discharge

unacceptable feelings; symbolic meanings.

Problem: Theory lacks support; interpretation of dreams difficult.

• Information Processing: Dreams may help sift, sort, and fix a day’s experiences in our memories.

Problem: dreams can contain events

not experienced.

Sigmund Freud(1856-1939)

Why Dream?• Physiological Function: Develop neural pathways.

Babies develop many new neural connection and require more sleep.

• Cognitive Development: Brain maturation and cognitive development.

Why Dream?• Activation-Synthesis Theory: random neural

activity; dreams attempt to make sense of this activity.

REM sleep is essential!

If deprived of REM sleep, REM rebound occurs.

Hypnosis

Hypnos: Greek god of sleep

One person (the hypnotist) suggests to another (the subject) that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur.

Hypnosis: Facts and Myths Power of Suggestion

Can anyone experience hypnosis? Yes, to some extent.

Can hypnosis enhance recall of forgotten events?

No.

Can hypnosis be therapeutic? Yes.

Can hypnosis alleviate pain? Yes.

Can hypnosis force people to act against their will?

No.

What Causes Hypnosis?

• Social Influence Theory: Playing acting; expectations.• Divided Consciousness Theory: Special state of

consciousness

ExampleBad smell attention is diverted

Social Influence Theory: told to ignore smell

Divided Consciousness Theory: consciousness/awareness split

Drugs and ConsciousnessPsychoactive Drug: A chemical substance that alters perceptions and mood (affects consciousness).

• Heroin• Inhalants• LSD• Marijuana• Nicotine• PCP • Rohypnol • 1,4-Butanediol

• Alcohol• Amphetamines • Barbiturates• Caffeine• Cocaine• Ecstasy• GHB • Hallucinogenic Mushrooms

Dependence & Addiction

Continued use of a psychoactive drug produces tolerance. With repeated exposure to a drug, the drug’s effect lessens. Thus it takes greater quantities to get the desired effect.

Withdrawal & Dependence

• Withdrawal: Upon stopping use of a drug (after addiction), users may experience the undesirable effects of withdrawal.

• Dependence: Absence of a drug may lead to a feeling of physical pain, intense cravings (physical dependence), and negative emotions (psychological dependence).

Psychoactive Drugs

Psychoactive drugs are divided into three groups.

1. Depressants

2. Stimulants

3. Hallucinogens

Depressants

Depressants: reduce neural activity and slow body functions.

1. Alcohol

2. Barbiturates

3. Opiates

DepressantsAlcohol: affects motor skills, judgment, and memory; increases aggressiveness while reducing self awareness.

Drinking and Driving

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Depressants

Barbiturates: reduce the activity of the central nervous system; reduce anxiety but impair memory and judgment.

Opiates (morphine and heroin): reduce neural activity, reduce pain and anxiety; highly addictive.

Stimulants

Stimulants: excite neural activity and speed up body functions.

• Caffeine • Nicotine• Cocaine• Ecstasy• Amphetamines• Methamphetamines

Caffeine & Nicotine

Caffeine and nicotine increase heart and breathing rates and other autonomic functions to provide energy.

Why Do People Smoke?

1. Socially rewarding.

2. Genetic factors.

3. Reduce unpleasant cravings

4. Rewarding

Cocaine

Cocaine induces immediate euphoria followed by a crash. Crack, a form of cocaine, can be smoked. Other forms of cocaine can be sniffed or injected.

Ecstasy(Methylenedioxymethamphetamine, MDMA)

Stimulant, mild hallucinogen.

Can damage serotonin-producing neurons

Possible depression, memory problems.

Image courtesy of Dr. GA Ricaurte, Johns Hopkins University School of Medicine

• LSD: (lysergic acid diethylamide) powerful hallucinogenic drug.

• THC (delta-9-tetrahydrocannabinol): major active ingredient in marijuana (hemp plant)

Hemp Plant

Hallucinogens

Distort perceptions; create sensory images without sensory input.

Drugs

Summary

After a close brush with death, many people report an experience of moving through a dark tunnel with a light at the end. Under the influence of hallucinogens, others report bright lights at the center of their field of vision.

Near-Death Experiences(From

“Hallucinations” by R

.K. Siegel. C

opyright ©

1977 Scientific Am

erican, Inc. All rights reserved.)