Human Physiology   7/e   Vander/Sherman/Luciano
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Chapter 13: Consciousness and Behavior


Study Outline

Chapter 13: Consciousness and Behavior

  1. CONSCIOUSNESS

    1. Consciousness includes states of consciousness and conscious experiences.

  2. STATES OF CONSCIOUSNESS

    1. The electroencephalogram provides one means of defining the state of consciousness.

      1. Electric currents in the cerebral cortex due predominately to summed postsynaptic potentials are recorded as the EEG.
      2. Slower EEG waves correlate with less responsive behaviors.
      3. Rhythm generators in the thalamus are probably responsible for the wavelike nature of the EEG.
      4. EEG is used to diagnose brain disease and damage.

    2. Alpha rhythms and, during EEG arousal, beta rhythms characterize the EEG of an awake person.
    3. Slow-wave sleep progresses from stage 1 (faster, lower-amplitude waves) through stage 4 (slower, higher-amplitude waves) and then back again, followed by an episode of REM (paradoxical) sleep. There are generally four or five of these cycles per night.
    4. Aminergic and cholinergic brainstem centers interact and, via their projections forward to the cerebrum as components of the reticular activation system, interact with the thalamus to regulate the sleep-wake cycles. Hypothalamic nuclei also play a role.

  3. CONSCIOUS EXPERIENCES

    1. Brain structures involved in directed attention determine which brain areas gain temporary predominance in the ongoing stream of conscious experience.
    2. Conscious experiences might occur by a set of neurons temporarily functioning together, with the neurons comprising the set changing as the focus of attention changes.

  4. MOTIVATION AND EMOTION

    1. Behaviors that satisfy homeostatic needs are primary motivated behaviors. Behavior not related to homeostasis is a result of secondary motivation.

      1. Repetition of a behavior indicates that it is rewarding, and avoidance of a behavior indicates it is punishing.
      2. The mesolimbic component of the reticular activating system, which goes to prefrontal cortex and parts of the limbic system, mediates emotion and motivation.
      3. Dopamine is the primary neurotransmitter in the brain pathway that mediates motivation and reward.

    2. Two aspects of emotion, inner emotions and emotional behavior, can be distinguished. The limbic system integrates inner emotions and behavior.

  5. ALTERED STATES OF CONSCIOUSNESS

    1. Schizophrenics manifest either mainly positive or negative symptoms. Hyperactivity in brain dopaminergic system is implicated in the disease.
    2. The mood disorders are caused, at least in part, by disturbances in transmission at brain synapses mediated by dopamine.
    3. Many psychoactive drugs, which are often chemically related to neurotransmitters, result in drug dependence, withdrawal, and tolerance. The mesolimbic component of the reticular activating system and the nucleus accumbens are implicated in substance abuse.

  6. LEARNING AND MEMORY

    1. The brain processes, stores, and retrieves information in different ways to suit different needs.
    2. Memory traces contain cellular or molecular changes specific to different memories.
    3. Procedural memories are memories of how to do things. Declarative memories are involved in remembering facts and events.
    4. Learning is enhanced after subjects are exposed to enriched environments. The enhancement is presumably due to the brain neural and chemical development that follows such exposure.

  7. CEREBRAL DOMINANCE AND LANGUAGE

    1. The two cerebral hemispheres differ anatomically, chemically, and functionally. In 90 percent of the population, the left hemisphere is superior at producing language and in performing other tasks that require rapid changes over time.
    2. The development of language functions occurs in a critical period that closes at puberty.
    3. After damage to the dominant hemisphere, some language function can be acquired by the opposite hemisphere; the younger the patient, the greater the transfer of function.

  8. CONCLUSION

    1. Many brain units are involved in the performance of even simple mental tasks.
    2. Each unit is localized to a specific brain area, but, because many units are involved, widely distributed brain areas take part in mental tasks.
    3. Little is known definitely about how consciousness and behavior are actually determined.

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