Measuring Consciousness

Researchers use the following operational definition of consciousness:
“If a cooperative person reports being aware of one stimulus and not of another, then he or she was conscious of the first and not the second.”

• consciousness: a state of awareness of ourselves and of the world around us.

• states of consciousness: levels of consciousness ranging from alert wakefulness to deep sleep.

• focused awareness: a state of heightened alertness in which one is fully absorbed in the task at hand.

  • wide awake, fully alert, completely engrossed in the task at hand

• drifting consciousness: a state of awareness characterized by drifting thoughts or mental imagery.

  • leads to daydreaming

• daydreaming: a form of consciousness during a waking state in which one’s mind wanders to dreamy thoughts or fantasies.

• Divided consciousness: a state of awareness characterized by divided attention to two or more tasks or activities performed at the same time.

• inattentional blindness: the failure to notice something right in front of your eyes because your attention is directed elsewhere.

• altered states of consciousness: states of awareness during wakefulness that are different than the person’s usual waking state.

• circadian rhythm : the pattern of fluctuations in bodily processes that occur regularly each day.

• Jet lag: a disruption of sleep–wake cycles caused by the shifts in time zones that accompany long-distance air travel.

stages of sleep

1-4: From Light to Deep Sleep

• stage 1 : brain waves become small and irregular with varying frequencies

  • sleeper can be easily awakened / not even realize they’re sleeping

• stage 2 : begins about 2 minutes after stage 1

  • bursts of brain wave activity represented by spindle-shaped waves called sleep spindles

  • people spend more than half of their sleep time in this stage

• stages 3 & 4 : called delta sleep or slow-wave sleep

  • difficult to awaken the person

  • distinction between Stage 3 and Stage 4 is based on the proportion of delta waves

    • Stage 3, delta waves constitute 50 percent or fewer of the brain wave patterns

    • Stage 4, they constitute more than 50 percent.

      • After Stage 4 sleep, the sleeper briefly recycles through Stages 3 and 2 and then enters REM sleep

rem sleep

• Rapid eye movement (REM) sleep: the stage of sleep that involves rapid eye movements and that is most closely associated with periods of dreaming.

  • where most dreams occur

  • brains become more active

    • Dreaming may also occur during stages 1 to 4; the stages of sleep collectively called non-REM

    • NREM : dreams are generally briefer and less detailed, less frequent, and more thought-like than story-like than dreams during REM sleep.

  • REM helps boost learning ability and creative problem-solving ability

why do we sleep?

• protective function in keeping the organism out of harm’s way

  • A sleeping animal may be less conspicuous to predators

• conserve bodily energy

  • lowering of body temperature during sleep may give warm-blooded animals more energy to maintain the higher body temperature they need during the waking state.

• a restorative function

  • helping the brain restore itself and recover from daily wear and tear

  • performing basic housecleaning functions by flushing out cellular waste products

• memory consolidation

  • the process by which freshly formed memories become lasting ones

activation-synthesis hypothesis: the proposition that dreams represent the brain’s attempt to make sense of the random discharges of electrical activity that occur during REM sleep.

• Sigmund Freud believed that dreams represent a form of wish fulfillment.

  • He called dreams the “royal road” to the unconscious mind

  • distinguished between two types of dream content:

  • 1. manifest content: the events that occur in a dream

  • 2. latent content: This is the true, underlying meaning of a dream, disguised in the form of dream symbols.

lucid dreams: dreams in which the dreamer is aware that he or she is dreaming.

Sleep Deprivation:

• preform poorly on tests & problem solving

• impaired memory

• more inclined to car accidents

• lowers immune system

  • investigators report that research participants who slept fewer than 7 hours a night were nearly 3x more likely to develop the common cold after exposure to a cold virus than those who slept 8 hours or more

• more inclined to get unhealthier food choices

  • less activity in the prefrontal cortex, the part of the brain that curbs impulsive behaviors, including impulsive eating

• result in costly errors

  • doctor the night before a surgery

Sleep-Wake Disorders

• sleep–wake disorders: a diagnostic category of psychological or mental disorders involving disturbed sleep patterns.

  • insomnia : difficulty falling asleep, remaining asleep, or returning to sleep after nighttime awakenings

    • traced to many factors, including substance abuse, physical illness, psychological disorders like depression, and even genetics

      • drugs used to treat insomnia can lead to physiological dependence and should only be used for a brief period of time, a few weeks at most

      • some are linked to increased risk of unusual behaviors, such as sleepwalking and driving or cooking while asleep

  • Narcolepsy : a sleep–wake disorder characterized by sudden unexplained “sleep attacks” during the day

    • REM sleep usually begins almost immediately after the onset of a narcoleptic attack

    • Genetics plays a role in narcolepsy, which, scientists suspect, is caused in many cases by a loss of brain cells in an area of the hypothalamus that produces a chemical needed to maintain wakefulness

      • stimulants may be used as treatments

  • sleep apnea : temporary cessation of breathing during sleep

    • caused by a structural defect, such as an overly thick palate or enlarged tonsils

    • most commonly affects middle age and older adults and obese people

  • nightmare disorder : a type of sleep–wake disorder involving a pattern of frequent, disturbing nightmares.

  • sleep terror disorder : a type of sleep–wake disorder involving repeated episodes of intense fear during sleep, causing the person to awake abruptly in a terrified state.

  • sleepwalking disorder : a sleep–wake disorder characterized by repeated episodes of sleepwalking

• meditation: a process of focused attention that induces a relaxed, contemplative state.

• transcendental meditation (TM): A form of meditation in which practitioners focus their attention by repeating a particular mantra.

  • mantra: a sound or phrase chanted repeatedly during transcendental meditation.

• mindfulness meditation: a form of meditation in which one adopts a state of nonjudgmental attention to the unfolding of experience on a moment-to-moment basis.

• hypnosis: an altered state of consciousness characterized by focused attention, deep relaxation, and heightened susceptibility to suggestion.

• hypnotic age regression: A hypnotically induced experience that involves reexperiencing past events in one’s life.

• hypnotic analgesia: A loss of feeling or responsiveness to pain in certain parts of the body occurring during hypnosis.

• posthypnotic amnesia: An inability to recall what happened during hypnosis.

• posthypnotic suggestion: A hypnotist’s suggestion that the subject will respond in a particular way following hypnosis.

• neo-dissociation theory: A theory of hypnosis based on the belief that hypnosis represents a state of dissociated (divided) consciousness.

• hidden observer: Hilgard’s term for a part of consciousness that remains detached from the hypnotic experience but aware of everything that happens during it.

• Psychoactive drugs: Chemical substances that affect a person’s mental or emotional state.

• drug abuse: Maladaptive or dangerous use of a chemical substance.

• polyabusers: People who abuse more than one drug at a time.

• drug dependence: A severe drug-related problem characterized by impaired control over the use of the drug.

• physiological dependence: A state of physical dependence on a drug caused by repeated usage that changes body chemistry.

• withdrawal syndrome: A cluster of symptoms associated with abrupt withdrawal from a drug.

• tolerance: A form of physical habituation to a drug in which increased amounts are needed to achieve the same effect.

• drug addiction: Drug dependence accompanied by signs of physiological dependence, such as the development of a withdrawal syndrome.

• Psychological dependence: A pattern of compulsive or habitual use of a drug to satisfy a psychological need.

• Internet addiction (IA): A nonchemical form of addiction characterized by excessive and maladaptive use of the Internet.

• Depressants: Drugs, such as alcohol and barbiturates, that dampen (slows down) central nervous system activity.

• intoxicant: A chemical substance that induces a state of drunkenness.

  • a single drink in women = two drinks in men

• Alcoholism: A chemical addiction characterized by impaired control over the use of alcohol and physiological dependence on it.

• narcotics: Addictive drugs that have pain-relieving and sleep-inducing properties. (opioids)

• Barbiturates : calming or sedating drugs that have several legitimate medical uses

• Stimulants: A drug that activates the central nervous system, such as amphetamines and cocaine.

• Hallucinogens: Drugs that alter sensory experiences and produce hallucinations.

• delirium: A mental state characterized by confusion, disorientation, difficulty in focusing attention, and excitable behavior.

The suprachiasmatic nucleus is located in the

• hypothalamus

Limited, answerable research questions:
• Why does consciousness exist?
• Does it have elements, analogous to the elements of chemistry?
• What does it accomplish?

Modern Methods to Measure Brain Activity

Electroencephalography (EEG) & magnetoencephalography (MEG)
• Simplest methods of measuring noninvasive brain activity.
• Detectors on scalp measure rapid changes in electrical or magnet activity.
• Approximate location of brain activity is measured.

Functional magnetic resonance imaging (fMRI)
• Identifies location of activity more precisely than EEG and MEG.
• Less precise measurement of timing.

Ways of Controlling Consciousness of a Stimulus

• Masking : is a procedure of preceding or following a stimulus with an interfering pattern that might prevent consciousness of the stimulus.

• Flash suppression : is a procedure of blocking consciousness of a stationary visual stimulus by surrounding it with rapidly flashing items.

• Attentional blink occurs when your attention to a first stimulus blocks notice of a second stimulus.

• Binocular rivalry is an alteration between seeing a pattern in the left retina and the pattern in a right retina.

When someone is conscious of a stimulus

• The stimulus activates neurons more
  strongly.

• Their activity reverberates through other
  brain areas.

• That activity rebounds to magnify the
  original response.

• The process inhibits responses to
  competing stimuli.

  
  

• all-or-none phenomenon : either the brain activity spreads strongly through the brain, or it does not.

• construction : conscious experience of a stimulus is a construction that can occur slightly after the stimulus itself, rather than simultaneously with it
  

Physicians distinguish various gradations of brain activity that relate to arousal, responsiveness, and presumed consciousness.

• Brain death: The brain shows no activity and no response to any stimulus

• Coma: The brain shows a steady but low level of activity and no response to any stimulus.

• Vegetative state: Limited responsiveness to stimuli, such as increased heart rate in response to pain.

• Minimally conscious state: Brief periods of purposeful actions and speech
  comprehension