consciousness

Consciousness

What is consciousness?

¨    People can be conscious even when they don’t appear to be

¨    All conscious experience is associated with brain activity

¨    Variations in consciousness occur naturally

¨    Consciousness can be manipulated

¨    Conscious experience varies from person to
person

Consciousness: one’s subjective experience of the world, resulting from brain activity

-       The brain and mind are inseparable.

-       Each of us experiences consciousness personally.

-       We cannot know if two people experience the world similarly.

The global workspace model

- consciousness arises as a function of which brain circuits are active.

§  In some cases, brain-injured patients are unaware of their deficits (hemineglect)

- Most importantly, the global workspace model presents no single area of the brain as responsible for general “awareness.”

Traumatic Brain Injury (TBI): impairments in mental functioning caused by a blow to or very sharp movement of the head
– TBIs can range from mild to severe.
– CTE: Chronic Traumatic Encephalopathy

Coma

Conditions of impaired consciousness provide valuable points of contrast to “normal” (fully functioning) consciousness.
– minimally conscious state
         • Deliberate movement and communication are possible.
– unresponsive wakefulness syndrome
         • complete coma that lasts more than a month
         • formerly known as a persistent vegetative state
         • Terri Schiavo

Brain Death: The irreversible loss of brain function.

o   Terri Schiavo had a severe brain injury, but there was still activity in her brain stem (cannot survive without it)

o   Jahi McMath suffered brain death after a routine tonsil surgery.

Locked-In Syndrome: Compared to being buried alive. You see all the sights around you and hear every noise, but you cannot respond physically to these sights and noises.
• Christine Waddell

-Automatic vs. controlled processing

-the cocktail party phenomenon

Selective Attention

·      Donald Broadbent developed filter theory to explain the selective nature of attention.
– In this model, attention is like a gate that opens for important information and closes for irrelevant details.
• Some stimuli demand attention and virtually shut off the ability to attend to anything else.
• Decisions about what to attend to are made early in the perceptual process.

Change Blindness: a failure to notice large changes in one’s environment

A Freudian slip occurs when an unconscious thought is suddenly expressed at an inappropriate time or in an inappropriate social context. ( When you say things

Subliminal Perception: the processing of information by sensory systems without conscious awareness.

Circadian rhythms: biological patterns that occur at regular intervals as a function of time of day
– Circadian roughly translates to “about a day.”

Sleeping Brain

·      The average person sleeps around 8 hrs per night (but this can vary).

·      Bright light suppresses the production of melatonin, whereas darkness triggers its release.

·      Information about light detected by the eyes is sent to a small hypothalamus region called the suprachiasmatic nucleus.
         – sends signals to a tiny structure called the pineal gland.

·      The pineal gland then secretes melatonin

·      EEG reveals the brain is active in sleep.
         – Beta waves: The EEG shows this activity as short, frequent, irregular brain signals.
Alpha waves: When people focus their attention on something or close their eyes and relax, brain activity slows and becomes more regular.

Stages of Sleep

·      Stage 1: The EEG shows theta waves

·      Stage 2: The EEG continues to show theta waves. It also indicates occasional bursts of activity called sleep spindles & large waves called K-complexes

·      Stages 3 & 4

o   Nowadays, they are typically seen as one stage because their brain activity is nearly identical.
– This period is marked by large, regular brain patterns called delta waves, often called slow-wave sleep.
– People in slow-wave sleep are very hard to wake up and are often very disoriented when they wake up.

REM sleep: The stage of sleep marked by rapid eye movement, paralysis of motor systems, and dreaming.

o   The sleep cycle reverses after about 90 min, returning to stage 1

o   Most dreaming occurs in REM sleep

o   About 80% of the time, when people are awakened during REM sleep, they report dreaming.

o   Cycle through REM five times per night

Sleep Disorders

·      Insomnia: a disorder characterized by an inability to sleep that cause significant problems in daily living.

o   An estimated 12 percent to 20 percent of adults have insomnia; it is more common in women than in men and older adults than in younger adults.

o   Obstructive sleep apnea: a person, while asleep, stops breathing because his or her throat closes.

§  It’s most common among middle-aged men and is often associated with obesity.

o   Narcolepsy: a sleep disorder in which people experience excessive sleepiness during normal waking hours, sometimes going limp and collapsing

§  During an episode of narcolepsy, a person may experience muscle paralysis accompanied with REM sleep, causing him or her to go limp and collapse.

o   REM behavior disorder: Sufferers act out their dreams while sleeping, often striking their sleeping partners (mostly seen in elderly males)

o   Somnambulism: sleepwalking

§  Most common in children

·      We cannot override the desire to sleep indefinitely. Eventually, our bodies shut down, and we sleep whether we want to or not.
– Research suggests sleep is adaptive for three functions:
         • restoration
         • following of circadian rhythms
         • facilitation of learning
– sleep deprivation:
         • problems in mood and cognitive performance
         • problems with the immune system

·      Circadian rhythm theory:

o   Many creatures are quiet and inactive at night because the darkness makes them more vulnerable to attack.
– reduced risk of exposure to predators
– Humans are adapted to sleeping at night because our early ancestors were more at risk in the dark.

·      Dreams: products of an altered state of consciousness in which images and fantasies are confused with reality
         – everyone dreams unless a particular kind of brain
         injury or a particular kind of medication interferes.

·      REM Dreams & Non-REM Dreams

o   REM Dreams: more likely to to be bizarre

o   Non-REM dreams: relatively dull

§  Non- REM dreams: general deactivation of many brain regions

§  REM dreams: brain structures associated w/ motivation, emotion, reward, & vision are active; the prefrontal cortex is not.

·      Freud: Dreams contain hidden content that represents unconscious conflicts.

o   Manifest contest: the plot of the dream

o   Latent content: what a dream symbolizes

§  There is no scientific evidence of this

·      Activation-synthesis theory: the brain tries to make sense of random brain activity that occurs during sleep by synthesizing the activity with stored memories

·      Hypnosis: a person, responding to suggestions, experiences changes in memory, perception, and/or voluntary action

o   Works primarily for suggestible people (who are open that  it will work)

·      Meditation: a mental procedure that focuses attention on an external object or on a sense of awareness

o   Concentrative meditation: focusing attention on one thing, such as your breathing pattern, a mental image, or a specific phrase (sometimes called a mantra)

o   Mindfulness meditation: letting your thoughts flow freely, paying attention to them but trying not to react to them

o   Popular in Hinduism, Buddhism, & Sikhism

o   Methods include Zen, Yoga, transcendental meditation

·      Ex. Of Escapist behaviors:

o   Drug & alcohol use

o   Excessive tv viewing

o   Surfing the web

o   Texting

o   Video games

·      Purposes of escapist behavior:

o   Distracts people from problems

o   Avoids feeling shameful for themselves

How do Drugs affect consciousness?

·      Drugs have been used throughout history to create altered states.

o   Around 317 million people use illicit drugs each year (United Nations Office on Drugs and Crime,2013b).

o   Other widely used drugs include alcohol, prescription medications, caffeine, and nicotine.

o   Addiction: drug use that remains compulsive despite its negative consequences

·      Why do people become addicted?

o   Physiological:

§  Activation of brain dopamine systems which play a role in the pleasurable experience that drugs create and regions (the insula) that govern cravings

§   Hereditary Alcoholism

o   Psychological:

§  high in the sensation-seeking personality trait

§  social learning (modeling drug use by others)