Emotion

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Chapter 11

• Emotion

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Emotions as response patterns

• Consists of 3 types of components
• Behavioral consists of muscular movements that
  are appropriate to the situation that elicits
  them
• e.g. dog defending its territory, growls and
  assumes aggressive posture
• Autonomic facilitate the behaviors and provide
  quick mobilization of energy for vigorous
  movement
• e.g. heart rate increase
• Hormonal reinforce the autonomic responses
• e.g. hormones secreted by the adrenal medulla
  (epinephrine and NE) further increase blood flow
  to muscles

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Fear

• Research with lab animals
• The integration of the 3 components of fear
  appears to be controlled by the amygdala
• Various nuclei of the amygdala become active when
  emotionally relevant stimuli are presented
• Major regions of the amygdala
• Medial nucleus receives sensory input,
  including info about the presence of odors, and
  relays it to the medial basal forebrain and
  hypothalamus
• Lateral nucleus (LA) receives sensory info from
  the primary somatosensory cortex, assc. Cortex,
  thalamus and hippocampal formation sends
  projections to basal, accessory basal, and
  central nucleus of the amygdala
• Central nucleus (CE) region of the amygdala
  that receives sensory info from the basal,
  lateral, and accessory basal nuclei and projects
  to a wide variety of regions in the brain
  involved in emotional responses damage to the CE
  results in a reduction or abolishment of a wide
  range of emotional behaviors and physiological
  responses

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Fear

• Research with lab animals (cont)
• CE important for aversive emotional learning
• Conditioned emotional response a classically
  conditioned response that occurs when a neutral
  stimulus (e.g. bell) is followed by an aversive
  stimulus (e.g. shock) usually included
  autonomic, behavioral, and endocrine components
  such as changes in heart rate, freezing, and
  secretion of stress-related hormones
• However, if an organism can learn a coping
  response (a response that terminates, avoids, or
  minimizes an aversive stimulus), the emotional
  responses will not occur
• CE necessary for development of a conditioned
  emotional response
• Research with humans
• Lesions of the amygdala decrease peoples
  emotional responses
• Damage to the amygdala interferes with the
  effects of emotions on memory

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Anger and aggression

• Species-typical behaviors
• Many related to reproduction (e.g. gain access to
  mate)
• Threat behaviors a stereotypical
  species-typical behavior that warns another
  animal that it may be attacked if it does not
  flee or show a submissive behavior displayed
  more often than actual attacks
• Defensive behaviors a species-typical behavior
  by which an animal defends itself against the
  threat of another animal
• Submissive behaviors a stereotyped behavior
  shown by an animal in response to threat behavior
  by another animal serves to prevent an attack
• Predation attack of one animal directed at an
  individual of another species on which the
  attacking animals normally preys

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Anger and aggression

• Neural control of aggressive behavior
• Particular muscle movements an animal makes in
  attacking or defending itself are programmed by
  neural circuits in the brain stem
• Activity of these circuits controlled by
  hypothalamus and amygdala
• Defensive behavior and predation can be elicited
  by stimulating the periaqueductal gray (PAG) of
  the cats midbrain
• The activity of serotonergic synapses inhibits
  aggression while destruction of serotonergic
  axons in the forebrain facilitates aggressive
  attack
• 5-HT does not simply inhibit aggression however,
  it appears to exert a controlling influence on
  risky behaviors
• In human subjects, depressed rates of 5-HT
  release are associated with aggression and other
  forms of antisocial behavior
• Functional imaging studies found an association
  b/t differences in the genes responsible for
  production of 5-HT transporters and the reaction
  of peoples amygdala to the viewing of facial
  expressions of negative emotions

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Anger and aggression

• Many investigators believe that impulsive
  violence is a consequence of faulty emotional
  regulation
• The prefrontal cortex plays an important role in
  recognizing the emotional significance of complex
  social situations and in regulating our responses
  to such situations
• Orbitofrontal cortex region of the prefrontal
  cortex at the base of the anterior frontal
  cortex its inputs provide it with info about
  what is happening in the envt and what plans are
  being made by the rest of the frontal lobes, and
  its outputs permit it to affect a variety of
  behaviors and physiological responses
• e.g. Phineas Gage damage to orbitofrontal
  cortex caused change in personality

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Hormonal control of aggressive behavior

• Many instances of aggressive behavior are in some
  way related to reproduction thus many forms of
  aggressive behavior are affected by hormones
• Aggression in males
• Inter-male aggressiveness begins around the time
  of puberty, suggesting that the behavior is
  controlled by neural circuits that are stimulated
  by androgens
• Early androgenization has an organizational
  effect that stimulates the development of
  testosterone-sensitive neural circuits that
  facilitate inter-male aggression
• Males able to discriminate sex of another animal
  by pheromones in order to not attack females,
  only other males
• Aggression in females
• Although not as common as in males, inter-female
  aggression appears to also be facilitated by
  testosterone
• While in the womb, female mouse fetuses that are
  situated b/t two male fetuses have significantly
  higher levels of testosterone

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Hormonal control of aggressive behavior

• Maternal aggression
• Most parents who actively raise their offspring
  will vigorously defend them against intruders
• Usually begins during pregnancy stimulated by
  progesterone (like nest building)
• However, if offspring are removed (e.g. via
  experimenter), or if the mothers nipples are
  surgically removed, will not display aggressive
  behaviors this is due to the necessity of either
  the pups odors or suckling stimuli
• Effects of androgens on human aggressive behavior
• Boys gt girls
• Socialization definitely effects this difference,
  but does biology too?
• Prenatal androgenization increases aggressive
  behaviors in all species that have been studied,
  including primates
• Difficult to study lack of androgens in human
  subjects thus, data with androgens in humans not
  very reliable
• Primary social effect of androgens may be not on
  aggression but on dominance
• However, CORRELATION does not imply CAUSATION!

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Hormonal control of aggressive behavior

• Effects of androgens on human aggressive behavior
• Synthetic hormones given to patients with
  abnormally low levels of testosterone
  (hypogonadal syndrome) does not increase
  aggressiveness
• However, athletes who take steroids (which
  include natural androgens) reported to be more
  hostile and aggressive although may be other
  reasons besides androgens for these behaviors
• Alcohol consumption may interact with the effects
  of androgen alcohol intake increases inter-male
  aggression in dominant squirrel monkeys, but only
  during mating season

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Communication of emotions

• Many species of animals, including our own,
  communicate their emotions to others by means of
  postural changes, facial expressions, and
  nonverbal sounds they all serve useful social
  functions
• Facial expression of emotions
• Darwin suggested that human expressions evolved
  from similar expressions in other animals he
  said that they are innate, unlearned responses
  consisting of a complex set of movements,
  principally of the facial muscles
• People in different cultures use the same
  patterns of movement of facial muscles to express
  a similar emotional state
• Display rules a culturally determined rule that
  modifies the expression of emotion in a
  particular situation

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Communication of emotions

• Neural basis of the communication of emotions
• Recognition
• The ability to display ones emotional state by
  changes in expression is useful only if other
  people are able to recognize them
• Emotional expressions greater when others present
• Right hemisphere more important than left in
  comprehension of emotions found a left-ear and
  left-visual field advantage in recognition of
  emotionally related stimuli
• When a message is heard, the right hemisphere
  assesses the emotional expression of the voice
  while the left hemisphere assesses the meaning of
  the words
• Patients with R hemisphere lesions have no
  trouble making emotional judgments about
  particular situations, but were impaired in
  judging the emotions conveyed by facial
  expressions or hand gestures (Your house seems
  empty without her vs. He scowled)
• Most severe damage to the ability to recognize
  facial emotional expressions was caused by damage
  to the somatosensory cortex of the R hemisphere

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Communication of emotions

• Neural basis of the communication of emotions
• Recognition (cont)
• A possible explanation for this may be that when
  we see a facial expression of an emotion, we
  imagine ourselves making that expression
• Indeed, patients with R hemisphere damage had
  both somatosensory impairments and impairments in
  recognition of emotions
• Amygdala plays a special role in emotional
  responses also, patients with amygdala lesions
  have an impairment in recognizing facial
  expressions, especially those of fear however,
  can still recognize emotions in tone of voice
• Gaze (i.e. the direction the other person/animal
  is looking) is important when recognizing facial
  expressions helps interpret whether or not
  expression is aimed at you
• Damage to basal ganglia disrupts a persons
  ability to recognize expressions of disgust

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Communication of emotions

• Neural basis of the communication of emotions
• Expression
• Automatic and involuntary
• Genuinely happy smiles involve the contraction of
  a muscle near the eyes, the lateral part of the
  orbicularis oculi
• Facial expressions follow real emotions
  difficult to express fully without any emotion
• Volitional facial paresis difficulty in moving
  the facial muscles voluntarily caused by damage
  to the face region of the primary motor cortex or
  its subcortial connections
• Emotional facial paresis lack of movement of
  facial muscles in response to emotions in people
  who have no difficulty moving these muscles
  voluntarily caused by damage to the insular
  prefrontal cortex, subcortical white matter of
  the frontal lobe, or parts of the thalamus
• Anterior cingulate cortex may be involved in the
  muscular movements that produce laughter damage
  to this area impairs ability to understand and be
  amused by jokes
• R hemisphere not only helps in recognizing
  emotion, but also more important for expressing
  them when people show emotions, the left side of
  face usually makes a more intense expression

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Communication of emotions

• Neural basis of the communication of emotions
• Expression (cont)
• Wada test a test that is often performed before
  brain surgery verifies the functions of one
  hemisphere by testing patients while the other
  hemisphere is anesthetized
• R hemisphere plays a role in primary emotions
  i.e. negative emotions
• Amygdala not involve in emotional expression

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Feelings of emotions

• The James-Lange theory
• A theory of emotion that suggests that behaviors
  and physiological responses are directly elicited
  by situations and that feelings of emotions are
  produced by feedback from these behaviors and
  responses
• Our own emotional feelings are based on what we
  find ourselves doing and on the sensory feedback
  we receive from the activity of our muscles and
  internal organs
• e.g. if we find ourselves trembling, we
  experience fear
• However, critiques say that internal organs are
  relatively insensitive, and could not respond
  quickly, so feedback from them could account for
  our feelings of emotions
• Theory difficult to verify experimentally
• Feedback from simulated emotions
• Feedback from the contraction of facial muscles
  can affect peoples moods and alter the activity
  of the ANS