Chapter 12: Emotional Behaviors


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The effects of emotions on our behavior and the brain processes involved.

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Chapter 12: Emotional Behaviors

  1. 1. Fear Anger Sadness Joy Disgust Surprise Emotional Behaviors
  2. 2. What is Emotion? Observable behaviors as opposed to feelings which are private experiences
  3. 3. Emotions & Arousal <ul><li>Strong Emotions </li></ul><ul><li>Impair reasoning but a lack of emotions can also lead to poor judgment </li></ul><ul><li>Absence Seizure </li></ul><ul><li>Originally called petite mal </li></ul><ul><li>Type of epilepsy where a person has brief periods when they stare blankly without talking or moving </li></ul>
  4. 4. Emotions & Arousal <ul><li>James-Lange Theory </li></ul><ul><li>Autonomic arousal & skeletal actions occur before an emotion </li></ul><ul><li>The cognitive component of an emotion does not need feedback from the rest of the body </li></ul><ul><li>Pure Autonomic Failure </li></ul><ul><li>Condition where output from the ANS to the body fails, either completely or almost completely </li></ul><ul><li>Locked-in Syndrome </li></ul><ul><li>Caused by damage to the ventral part of the brain stem </li></ul>
  5. 5. Emotions & Arousal <ul><li>Panic Disorder </li></ul><ul><li>A condition marked by episodes of extreme sympathetic nervous system arousal interpreted as fear </li></ul><ul><li>Perceptions of Bodily Reactions are Important for Interpreting Emotions </li></ul><ul><li>Extreme arousal is recognized as fear or panic </li></ul><ul><li>Stimuli inducing smiling or laughter are considered pleasant or amusing </li></ul>
  6. 6. Emotion Areas in the Brain <ul><li>Limbic System </li></ul><ul><li>Includes: cingulated cortex, hypothalamus, thalamus, hippocampus, amygdala & olfactory bulbs </li></ul><ul><li>Other Emotional Areas </li></ul><ul><li>Medial frontal cortex (anger) & insular cortex (disgust) </li></ul><ul><li>Hemispheric Response to Emotions </li></ul><ul><li>Right hemisphere especially activated by unpleasant emotions </li></ul>
  7. 7. Stress & Health <ul><li>Stress </li></ul><ul><li>A nonspecific response of the body to any demand made on it </li></ul><ul><li>Psychosomatic Illness </li></ul><ul><li>An illness whose onset is influenced by personality, emotions or experience </li></ul><ul><li>Ulcers: from a combination of bacteria & current & past experiences & drugs irritating the digestive system wall </li></ul><ul><li>Heart disease: more common in frequently hostile individuals </li></ul><ul><li>Voodoo death: due to the belief that a curse has destined death </li></ul><ul><li>Serendipity: stumbling on something interesting while looking for something else </li></ul>
  8. 8. Stress & the HPA Axis <ul><li>Stress Activates the ANS & the HPA Axis </li></ul><ul><li>Prolonged stress keeps the HPA axis active </li></ul><ul><li>Stress activates the hypothalamus which sends messages to the anterior pituitary gland to secrete ACTH </li></ul><ul><li>ACTH stimulates the adrenal cortex to secrete cortisol, which increases blood sugar levels & enhances metabolism </li></ul>
  9. 9. The Immune System <ul><li>Leukocytes </li></ul><ul><li>White blood cells produced in the bone marrow before migrating to the thymus gland, spleen, & peripheral lymph nodes </li></ul><ul><li>They patrol the blood & other body fluids looking for intruders </li></ul><ul><li>Antigens </li></ul><ul><li>Antibody-generator molecules </li></ul><ul><li>Proteins located on a cell’s surface </li></ul><ul><li>When leukocytes discover cells with antigens different from the rest of the body, they attack </li></ul>
  10. 10. The Immune System <ul><li>Macrophages </li></ul><ul><li>A cell that surrounds a bacterium or other intruder, digests it & exposes its antigens on the microphages own surface </li></ul><ul><li>B & T Cells </li></ul><ul><li>B cells are leukocytes which mature on the bone marrow & produce specific antibodies to attack an antigen </li></ul><ul><li>T cells are leukocytes which mature in the thymus </li></ul><ul><li>There are 2 types of T cells: cytotoxic T cells which directly attack an intruder & helper T cells which stimulate other T cells or B cells to multiply more rapidly </li></ul>
  11. 11. The Immune System <ul><li>Antibodies </li></ul><ul><li>Y-shaped proteins that circulate in the blood & attach to one specific kind of antigen </li></ul><ul><li>The body develops antibodies against antigens that it has encountered in the past </li></ul>
  12. 12. The Immune System <ul><li>Natural Killer Cells </li></ul><ul><li>Blood cells which attach to cells infected with viruses & certain kinds of tumor cells </li></ul><ul><li>Cytokines </li></ul><ul><li>Chemicals released by the immune system which cross the blood-brain barrier & influence neuronal function </li></ul>
  13. 13. Psychoneuroimmunology <ul><li>Stress & the Immune System & the CNS </li></ul><ul><li>How stress influences the immune system & how the immune system influences the CNS </li></ul><ul><li>The body can handle stressors like illness </li></ul><ul><li>Prolonged stress leads to prolonged increases in cortisol & other hormones </li></ul><ul><li>This directs energy away from synthesizing proteins, including immune system proteins </li></ul><ul><li>Extremely prolonged stress weakens the immune system </li></ul><ul><li>High cortisol levels impair memory & increase the vulnerability of neurons in the hippocampus </li></ul><ul><li>Toxins from overstimulation kill neurons </li></ul>
  14. 14. Posttraumatic Stress Disorder <ul><li>Symptoms </li></ul><ul><li>Frequent distressing flashbacks & nightmares about the event, avoidance of reminders of it, & exaggerated arousal in response to noises & other stimuli </li></ul><ul><li>Victims have a smaller than average hippocampus & lower than normal levels of cortisol </li></ul>
  15. 15. Attack Behaviors <ul><li>Trigger is Some Sort of Pain or Threat </li></ul><ul><li>Primed by stimulating corticomedial area of the amygdala (seen in hamsters) </li></ul><ul><li>This area shows increased neural activity immediately after a 1 st attack </li></ul><ul><li>Heredity & Environment in Violence </li></ul><ul><li>Evidence of genetic influences in aggression, antisocial & criminal behavior (twin studies) </li></ul><ul><li>Monozygotic twins more likely to commit crimes & be aggressive than dizygotic </li></ul><ul><li>Adoptees with parents with criminal records more likely to exhibit aggressive behaviors </li></ul>
  16. 16. Attack Behaviors <ul><li>Hormones </li></ul><ul><li>In animals, male aggressive behavior is linked to testosterone </li></ul><ul><li>In humans, higher levels of testosterone related to higher violent activities and criminal behaviors </li></ul><ul><li>Women injected with testosterone showed increase in heart rate when looking at a picture of angry face </li></ul><ul><li>Suggests that testosterone may induce people to attend longer & respond more vigorously to certain situations </li></ul>
  17. 17. Attack Behaviors <ul><li>Brain Abnormalities & Violence </li></ul><ul><li>Intermittent explosive disorder: </li></ul><ul><li>Condition marked by occasional outbursts of violent behavior with little or no provocation </li></ul><ul><li>Sometimes linked with temporal lobe epilepsy </li></ul><ul><li>Damage to the prefrontal cortex induces fighting & threatening responses with less provocation </li></ul><ul><li>Prefrontal damage causes a general loss of inhibition & a tendency toward many socially inappropriate behaviors, not just violence </li></ul>
  18. 18. Attack Behaviors <ul><li>Serotonin Synapses & Aggressive Behavior </li></ul><ul><li>Turnover: The amount of release & resynthesis of a neurotransmitter by a presynaptic neuron </li></ul><ul><li>Social isolation induces a drop in serotonin turnover in brains of male mice; this further increases the possibility of aggressive behavior toward other males </li></ul><ul><li>Monkeys with the lowest serotonin turnover had the highest amount of aggressive behaviors; they also died earlier </li></ul><ul><li>Low serotonin turnover are not only linked specifically to violence but to decreased inhibition impulses </li></ul><ul><li>In humans, lower-than-normal serotonin turnover was found in those convicted of violent crimes or attempted suicides </li></ul><ul><li>Neurons synthesize serotonin from tryptophan </li></ul><ul><li>A diet high in other amino acids but low in tryptophan impairs the brain’s ability to synthesize serotonin </li></ul><ul><li>An increase in aggressive behaviors was found in young men a few hours after eating a diet low in tryptophan </li></ul>
  19. 19. Escape, Fear & Anxiety The Amygdala Fear is a temporary experience Anxiety is longer lasting The startle reflex The response to a sudden, unexpected loud noise The amygdala enhances the startle reflex by sending axons to the hypothalamus & relaying information to the central gray area of the midbrain
  20. 20. Escape, Fear & Anxiety <ul><li>Urbach-Wiethe Disease </li></ul><ul><li>A genetic disorder causing gradual atrophy of the amygdale </li></ul><ul><li>Produces a weakened experience of fear-related emotions </li></ul><ul><li>Those with this disorder have difficulty recognizing fear in others </li></ul>
  21. 21. Anxiety-reducing Drugs <ul><li>Cholecystokinin </li></ul><ul><li>One of the main excitatory neuromodulators in the amygdale </li></ul><ul><li>Injections of CCK-stimulating drugs into the amygdala enhances the startle reflex </li></ul><ul><li>Gamma Amino Butyric Acid (GABA) </li></ul><ul><li>Main inhibitory neurotransmitter in the amygdale </li></ul><ul><li>Injections of GABA-blockers induce panic </li></ul><ul><li>Barbiturates </li></ul><ul><li>Tranquilizers of years back </li></ul><ul><li>Are addicting & can be fatal </li></ul>
  22. 22. Anxiety-reducing Drugs <ul><li>Benzodiazepines </li></ul><ul><li>Commonly used class of tranquilizers </li></ul><ul><li>Includes: diazepam, chlordiazepoxide & alprozolam </li></ul><ul><li>They bind to a receptor site on the GABA A receptor complex which causes the receptor to change shape & bind more tightly </li></ul><ul><li>They exert their antianxiety effects in the amygdala & hypothalamus </li></ul>
  23. 23. Anxiety-reducing Drugs <ul><li>Diazepam-binding Inhibitor (DBI) aka Endozepine </li></ul><ul><li>A protein that binds to the same sites as benzodiazepines but blocks their behavioral effects </li></ul><ul><li>Alcohol’s effects </li></ul><ul><li>Alcohol has similar behavioral effects as benzodiazepines </li></ul><ul><li>Combinations of alcohol & tranquilizers can be fatal </li></ul><ul><li>Alcohol, benzodiazepines & barbiturates exhibit cross-tolerance </li></ul>