Ch.4 State of Consciousness

Consciousness

Our awareness of internal and external stimuli

Internal stimuli

Pain, hunger, thirst, being aware of our thoughts and emotions

External stimuli

Seeing the light from the sun, feeling the warmth of a room, hearing the voice of a friend

Wakefulness

high levels of sensory awareness, thought, and behavior; being alert

Sleep

A state marked by relatively low levels of physical of activity and reduced sensory awareness distinct from periods of rest that occur during wakefulness

Altered state of consciousness

State in which there is a shift in the quality or pattern of mental activity as compared to wakefulness

• daydreaming

• Intoxication

• Anesthesia

Biological rhythms

Internal cycles of biological activity

Circadian rhythms

Biological rhythm that occurs over approximately 24 hrs

• sleep-wake cycle is linked to our environment’s natural light-dark cycle

Hypothalamus

Homeostasis center

Suprachiasmatic Nucleus (SCN)

The brain clock mechanism.

Enables our internal clock to be synced with the outside world

What do the Pineal glands do?

Release melatonin and maintain various biological rhythms

Melatonin

Hormone that regulates sleep-wake cycle

• stimulated by darkness (sleepy)

• Inhibited by light (wakeful)

What is sleep?

A state marked by relatively low levels of physical activity and reduced sensory awareness

Sleep regulation

the brain’s control of switching between sleep and wakefulness and coordinating this cycle with the outside world

• can be disrupted by jet lag, insomnia, rotating shift work

Sleep debt

Insufficient sleep on a chronic basis

Sleep rebound

tendency to fall asleep faster during subsequent opportunities for sleep (when in sleep debt)

Effects of sleep debt and sleep deprivation

• irritability

• cognitive impairment

• impaired immune system

• risk of diabetes type 2

• increased heart rate variability

• risk of heart disease

• increased reaction time

• decreased accuracy

• growth suppression

• risk of obesity

How much sleep do we need?

Average of 7-9 hours each nigh for adults

• sleep quality matters too

• younger need more; older less

why do we sleep?: Adaptive Perspective (evolutionary)

• Sleep is essential to restore resources expended during the day

• Avoid predators in darkness

• WHEN we sleep

Restorative Perspective (cognitive)

• Physical health restoration

  • replenish chemicals and repair cellular damage

• Mental health functioning

  • attention, decision-making, memory, emotions

• WHY we sleep

Electroencephalogram (EEG)

• Brain waves are studied by placing electrodes on scalp

• When neurons fire, they produce electrical activity (brainwaves)

• Researchers can record electrical activity in response to certain stimuli or during different states of consciousness

Rapid-Eye Movement (REM) Sleep

• Eyes move rapidly under the eyelids

• Brainwaves appear similar to those during wakefulness

• Dreaming

Non-REM (NREM) Sleep

All the other stages of sleep, distinguished by brainwave activity

Brainwaves during Sleep

Brainwave activity (measured with EEG) changes dramatically across the different sleep stages

NREM Stage 1

• Transitional phase occurring between wakefulness and sleep

• Rates of respiration and heartbeat slows down

• Overall muscle tension and core body temperature decrease

• “Light Sleep”

  • mostly alpha waves

  • easy to wake up

NREM Stage 2

• The body goes into deep relaxation

• Theta waves

• Characterizes by the appearance of:

  • Sleep spindles

  • K-complexes

Sleep Spindles

rapid burst of high frequency brainwaves

• learning and memory

K-complexes

very high amplitude pattern of brain activity

NREM Stage 3

• Respiration and heart rate slow down further

• Known as slow-wave sleep

• “Deep Sleep”

  • Delta waves

  • Difficult to wake someone up v

REM Sleep

• Paralysis of voluntary muscles

• Brain waves are similar to those seen during wakefulness

• Dreams

• Important for emotion regulation, creating new synapses in the brain (learning and memory)

  • Infants spend HALF of their sleep time in REM stage

Stages of Sleep

• 4-6 cycles per night

  • 90-110 minutes each

• The depth of out sleep alternates up and down many times

Dreams

• 6 years of your life is spent dreaming

• 10,000 dreams in a lifetime

• most reflect real-life worries, hopes desires

• Most involve people and places you know

Theories of Why We Dream: Wish Fulfillment Theory

• Freud

• Dreams preserve our sanity by allowing us to gratify forbidden or unrealistic wishes

• Dream content may be so threatening or disgusting that it was disguised in dreams

Manifest Content

Dream content

Latent Content

Dream’s true meaning

Theories of Why We Dream: Information Processing Theory

• Rosalind Cartwright

• Dreams reflect daily life events that are important to us

  • Help us sift through our everyday experiences and thoughts

  • Help us regulate emotions

Theories of Why We Dream: Activation Synthesis Hypothesis

• Alan Hobson

• Dreams are a result of out brains imposing narrative explanations to explain random brain activation

  • Synthesize= make sense of

  • Activation= neural activity during REM

• Cerebral cortex tries to make sense of this random brain stimulation (pons; brainstem)

Insomnia

Difficulty falling or staying asleep

Sleep Apnea

Multiple bursts of not breathing

Narcolepsy

Sudden slip into sleep, often directly to REM sleep

Night Terrors

• Rare(common in children)

• Extreme fear, panic, screaming

REM Behavior Disorder

• Mechanism that blocks the movement of the voluntary muscles fails

• Acting out dreams (kicking, punching, yelling)

Sleepwalking (Somnambulism)

• Complex behaviors with eyes open but still asleep

• NREM Stage 3 (slow-wave)

Basic Science

interested in developing a fundamental understanding of how things work

• what is sleep? why do we sleep? How do we sleep?

Applied Science

Interested in solving practical problems

• How can we intervene with, or improve, sleep?

Substance Abuse

a compulsive pattern of drug use despite negative consequences

Physical dependence

need to take a drug to avoid changes in normal bodily functions and withdrawal symptoms

Psychological dependence

Emotional need for a drug; thoughts about getting/using a drug

Tolerance

Occurs when a person requires more and more of a drug to achieve effects previously experienced at lower doses

Withdrawal

adverse symptoms experienced when drug use is discontinued

Stimulants

Drugs that increase levels of neural activity

• associated with reward and pleasure (highly addictive)

Stimulants example

Caffeine, Nicotine, Cocaine, Amphetamines, MDMA

Stimulants Effects on the Body

Increased heart rate, blood pressure, body temperature

Stimulants When Used

Increased alertness, mild euphoria, decreased appetite in low doses. High doses increase agitation, paranoia, can cause hallucinations.

Depressants

Drugs that suppress the central nervous system activity

• Act as agonists of GABA neurotransmitters, which have a “quieting effect” on the brain

Depressants examples

• Alcohol

• Barbiturates

• Benzodiazepines (Xanax)

Depressants Effects on the body

Decreased heart rate, blood pressure

Depressants Effects when used

Low doses increase relaxation, decrease inhibitions. High doses can induce sleep, cause motor disturbance, memory loss

Opiates

Serve as analgesics (decrease pain) through their effects on the endogenous opioid neurotransmitter system

• Highly addictive

Opiates Examples

• Opium

• Heroin

• Fentanyl

• Morphine

• Oxycodone

Opiates Effects on the body

decreased pain, pupil dilation, decreased gut motility, decreased respiratory function

Opiates Effects when used

Pain relief, euphoria, sleepiness. High doses can cause death due to respiratory depression

Hallucinogens

Cause chances in sensory and perceptual experiences

Hallucinogens examples

• cannabis

• LSD

• Peyote

Hallucinogens effects on the body

increased heart rate and blood pressure that may dissipate over time

Hallucinogens effects when used

Mild to intense perceptual changes with high variability in effects based on strain

Hypnosis

a state of extreme self focus and attention in which minimal attention is given to external stimuli

Theories of Hypnosis: Dissociation Theory

• Divided consciousness

• One stream of mental activity occurs outside of awareness and control

  • ex: not remember act of driving

Theories of Hypnosis: Social-Cognitive Theory

• People are playing the role expected of them in the situation

• not an altered or dissociative state, but fulfilling social expectations