States of Consciousness

Mouse Party&

Spiders on Drugs+ Rusty the Narcoleptic Dog

• http://learn.genetics.utah.edu/units/addiction/drugs/mouse.cfm

• http://www.collegehumor.com/video/236466/spiders-on-drugs

• http://www.youtube.com/watch?v=JB4Z0LNGBPY

Defining consciousness

Consciousness can be viewed as our subjective awareness of mental events

Consciousness may have evolved to direct or control behavior in adaptive ways

• William James (1890):–Consciousness is a constantly moving

stream of thoughts, feelings, and emotions

• Functions of consciousness:–Monitoring mental events–Control: consciousness allows us to

formulate and reach goals

altered states of consciousness

• sleep, • hypnosis, • near-death experiences, • coma, • daydreaming

Cortex and Consciousness

• The dorsolateral prefrontal cortex is activated during conscious control tasks

– Stroop task: Subjects asked to name the ink color have difficulty when the word name and color are different

– This color-naming task was associated with activation of the dorsolateral prefrontal cortex

Attention

Attention refers to the process by which we focus our awareness

• Our conscious awareness is limited in capacity • we are aware of only a small amount of the stimuli

around us at any one time

Three functions of attentional processes:

• Orienting function toward the environment• Control of the content of consciousness

I will think about this issue but not that one…• Maintaining alertness

Divided Attention

• refers to a task in which a person is asked to attend to two tasks at the same time– Subject may be asked to

listen to one conversation delivered via the left ear

– Some information on the other channel (right ear) is processed (as shown in priming tasks)

Flow of Consciousness

• Day-dreams are shifts in attention toward internal thoughts and imagined scenarios– College students may spend as much as 50% of

their waking time in a day-dream • uhh, are you folks paying attention out there????

– Beeper studies of high-school students have noted the predominance of negative thoughts when students are with their families as opposed to others

Psychodynamic View of Consciousness

• Freud argued that three mental systems form consciousness– Conscious: mental events that you

are aware of– Preconscious: Mental events that

can be brought into awareness– Unconscious: Mental events that

are inaccessible to awareness; events are actively kept out of awareness

Blindsight• People with damage to the central portion of the

occipital cortex – are blind in the sense that they are unable to see

objects placed before them– are able to provide partial information about the

geometric shape of an object (blindsight)• Blindsight may involve a primitive visual system in

the midbrain

Neurology of Consciousness• Consciousness is

distributed throughout the brain– Hindbrain and midbrain are

important for arousal and for sleep

– Damage to the reticular formation can lead to coma

– Prefrontal cortex is key for conscious control of information processing

sleep and dreams

• various theories • common sleep disorders

• sleep is not a passive process, but rather involves interactions between the thalamus and the cortex.

Species Variation in Sleep

© 2002 John Wiley & Sons, Inc.

(Figure adapted from Kripke et al., 1979)

Function of Sleep

• Memory consolidation• Energy conservation • Preservation from predators• Restoring bodily functions– Sleep deprivation can alter immune function

and lead to early death– Sleep deprivation can also lead to

hallucinations and perceptual disorder

© 2002 John Wiley & Sons, Inc.

Sleep and Dreaming

• Behavioral characteristics of sleep– Minimal movement– Stereotyped prone posture– Require a high degree of stimulation to arouse

organism• Physiological characteristics of sleep– Brain wave activity (seen in the EEG)– Paralysis of muscles (seen in the EMG)– Cardiovascular changes (alternating cycles of

arousal)

REM Sleep

• Characteristics of REM sleep– Presence of rapid-eye-movements– Presence of dreaming– Increased autonomic nervous system activity– EEG resembles that of awake state (beta wave)– Motor paralysis (except for diaphragm)

© 2002 John Wiley & Sons, Inc.

REM and NREM

• contrast rapid eye movement (REM) and nonrapid eye movement (NREM) sleep

EEG Stages of Sleep

© 2002 John Wiley & Sons, Inc.

(Figure adapted from Cartwright, 1978)

Dreaming

• Psychoanalytic view: Dreams represent a window into the unconscious– The latent content (meaning) can be inferred from the

manifest content (the actual dream)

• Cognitive view: Dreams are constructed from the daily issues of the dreamer

• Biological view: Dreams represent the attempt of the cortex to interpret the random neural firing of the brain during sleep

© 2002 John Wiley & Sons, Inc.

Sleep Disorders• Insomnia is the inability to achieve or maintain sleep• Many causes for insomnia:– Stress– Depression– Sleeping pills (iatrogenic means physician-caused)

• Some suggestions for treating insomnia– Only use your bed for sleeping– Avoid physical activity prior to sleep– Avoid consumption of caffeine and alcohol before bed– Keep a regular sleep schedule – Go to bed when you are ready(do not force sleep)– Do not sleep during the day if you have insomnia

© 2002 John Wiley & Sons, Inc.

Other Sleep Disorders

• Nightmares are vivid fear-evoking dreams– Occur during REM sleep

• Night Terrors: are episodes of intense panic– Occur during delta sleep (early in night)

• Sleep apnea: refers to awakening brought on by cessation of breathing during sleep

• Narcolepsy: falling asleep during the day

© 2002 John Wiley & Sons, Inc.

Mortality Rates and Sleep

© 2002 John Wiley & Sons, Inc.

(Figure adapted from Kripke et al., 1979)

Altered States of Consciousness

• Changes in consciousness can be brought on by– Meditation– Hypnosis– Drug ingestion– Religious experiences

© 2002 John Wiley & Sons, Inc.

Hypnosis• Hypnosis is a state of consciousness characterized by– Deep relaxation– Suggestibility

• Effects observed during hypnotic state:– Age regression– Change in pain perception– Ability to recall memories into consciousness

© 2002 John Wiley & Sons, Inc.

Changes in Pain Perception during Hypnosis

• Hilgard’s demonstration of the “Hidden Observer”– Subjective pain report

depends on the aspect of consciousness that is reporting on pain

© 2002 John Wiley & Sons, Inc.(Figure adapted from Hilgard, 1986, p. 190)

Drug-Induced States of Consciousness

• Drug effects on consciousness depend on:– Biological actions of the drug

• Usually involve drug action at brain synapses– Expectations of drug effect (what effect are you expecting

from the drug?)• Drug classes– Depressants (including alcohol)– Stimulants (amphetamine, cocaine)– Hallucinogens (LSD)– Marijuana

© 2002 John Wiley & Sons, Inc.

the effects of psychoactive drugs

Methamphetamines user first pictured in 2001, left, and then in 2008

EEG

• the role of electroencephalographs (EEGs)