1. Chapter 12 Biology of Emotion

2. What is Emotion?
Psychologists define emotion in terms of three components:
Cognition
Action
Feeling

3. Emotions, Autonomic Arousal, and the James-Lange Theory
Emotional situations arouse the autonomic nervous system
Each situation evokes its own special mixture of sympathetic and parasympathetic arousal

5. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)
The James-Lange theory of emotion suggests that autonomic arousal and skeletal action occurs first in an emotion
The emotion that is felt is the label that we give the arousal of the organs and muscle

6. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)

7. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)
James-Lange theory leads to two predictions:
People with a weak autonomic or skeletal response should feel less emotion
Increasing one’s response should enhance an emotion

8. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)
Research indicates the following:
Paralyzed people report feeling emotion to the same degree as prior to their injury
People with “pure autonomic failure” still report feeling emotion but less intensely
Pure autonomic failure: output from autonomic nervous system to body fails
Suggests other factors are involved in the perception of emotion

9. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)
BOTOX blocks transmissions at synapses and nerve-muscle junctions
People with BOTOX injections show:
Slower time in reading unhappy sentences
Weaker than usual emotional responses after watching short videos
Points to body change being important for feeling an emotion
However, people with certain types of brain damage show “normal” responses

10. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)
According to the James-Lange theory, emotional feelings result from the body’s action
Panic attacks are marked by extreme sympathetic nervous system arousal (rapid heartbeat, fast breathing, etc.)
Only if perceived as occurring spontaneously

11. Emotions, Autonomic Arousal, and the James-Lange Theory (cont’d.)
Creating certain body actions may also slightly influence emotion
Smiling slightly increases happiness
Inducing a frown leads to the rating of stimuli as slightly less pleasant
Indicates that perception of the body's actions do contribute to emotional feeling
However, body’s actions are not required
Example: Möbius syndrome
(see a video here: )

14. Brain Areas Associated with Emotion
Emotional experiences arouse many areas of the brain
The limbic system includes the forebrain areas surrounding the thalamus
Traditionally been regarded as critical for emotion
PET and fMRI studies also suggest many other areas of the cerebral cortex, especially the frontal and temporal lobes, are activated during an emotional experience

16. Brain Areas Associated with Emotion (cont’d.)
Measurement of evoked responses indicate the brain is specialized to attend strongly to facial expressions
Emotions tend not to be localized in specific parts of the cortex
A single emotion increases activity in various parts of the brain

18. Brain Areas Associated with Emotion (cont’d.)
Localization in the brain seems to exist for the emotion of disgust
The insular cortex is strongly activated during exposure to stimuli perceived as “disgusting”
Also the primary taste cortex
Also reacts to frightening stimuli and angry faces, so not completely dedicated to disgust

19. Brain Areas Associated with Emotion (cont’d.)
The two hemispheres of the brain play different roles in emotion
Activation of the frontal and temporal areas of the left hemisphere is associated with “approach” and the Behavioral Activation System
Marked by low to moderate arousal
Can characterize either happiness or anger

20. Brain Areas Associated with Emotion (cont’d.)
The Behavioral Inhibition System (BIS) is associated with increased activity of the frontal and temporal lobe of the right hemisphere
Increases attention and arousal
Inhibits action
Stimulates emotions such as fear and disgust

21. Brain Areas Associated with Emotion (cont’d.)
Differences in frontal cortex activity relates to personality
People with greater activity in the left hemisphere tend to be happier, more out-going, and friendlier
People with greater right hemisphere activity tend to be socially withdrawn, less satisfied with life, and prone to unpleasant emotions

22. Brain Areas Associated with Emotion (cont’d.)
The right hemisphere seems to be more responsive to emotional stimuli than the left
Damage to the right temporal cortex causes problems in the ability to identify emotions of others
Wada test: One hemisphere at a time was anesthetized by drug injection into one of the carotid arteries, which provide blood to the head, used before certain kinds of brain surgery.
See video :
When the right hemisphere is inactived, people do not experience strong emotions and don’t remember feeling them

23. The Functions of Emotions
Functions of emotions include:
Adaptive values (fear leads to escape, anger lead to attack, etc.)
Allow us to make quick decisions
Help us make moral decisions

24. The Functions of Emotions (cont’d.)
The consequences of our decisions have emotional considerations
Emotions are an important component to moral decisions
Failure to anticipate the unpleasantness of an event can lead to bad decision making
Contemplating moral decisions activates the prefrontal cortex, cingulate gyrus, and amygdala

26. The Functions of Emotions (cont’d.)
Damage to the prefrontal cortex impairs decision making
Leads to impulsive decision-making without pausing to consider consequences
Stems from failure to anticipate unpleasantness of an outcome
Example: Phineas Gage
Those with damage to the ventromedial prefrontal cortex show decreased guilt

27. The Functions of Emotions (cont’d.)
Phineas P. Gage was an American railroad construction foreman remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe.

28. The Functions of Emotions (cont’d.)
Damasio (1994) examined a man with prefrontal cortex damage who expressed almost no emotions.
Nothing angered him. He was never very sad, even about his own brain damage. Nothing gave him much pleasure,
Rational, but he frequently made bad decisions that cost him his job, his marriage, and his savings.
When tested in the laboratory, he successfully predicted the probable outcomes of various decisions, but he apparently did not anticipate that one action would win him approval would feel good and trouble would feel bad
Failure to anticipate the unpleasantness of likely outcomes leads to bad decisions.

29. Attack and Escape Behaviors
Attack and escape behaviors are closely related physiologically and behaviorally
Related with the sympathetic nervous system (fight-or-flight system)
Corresponding behaviors are anger and fear

30. Attack Behaviors
Pain, threat, or other unpleasant stimuli can trigger an attack behavior
Attack behaviors are associated with increased activity in the the amygdala
After experiencing a provocation, people are more likely to attack for a period of time afterwards
An initial attack behavior increases the probability of a second attack behavior

32. Attack Behaviors (cont’d.)
Environmental factors associated with increased violent tendencies include:
Exposure to lead which is harmful to developing brains.
Since the banning of lead-based paints and the rise of unleaded gasoline, the prevalence of violent crime has declined,
Witness or victim of violence in childhood
Living in a violent neighborhood

33. Attack Behaviors (cont’d.)
Twins studies suggest genetic contribution to the likelihood of violent behavior
Monozygotic twins resembled each other much more than dizygotic twins with regard to violent and criminal behavior
Attempts to identify a specific gene have found only a weak effect
Example: one gene linked to aggression only found among people with Finnish ancestry

34. Attack Behaviors (cont’d.)
Hormones also influence aggressive behavior
Male aggressive behavior is influenced by the hormone testosterone
On average, males engage in more aggressive and violent behaviors than do females
Research shows that men with the highest rates of violent behavior also have slightly higher testosterone levels
Watch video:

36. Attack Behaviors (cont’d.)
“Triple imbalance hypothesis”: violence depends on other chemicals besides testosterone, notably cortisol (stress hormone) and serotonin
Aggression levels are highest when cortisol levels are low and testosterone levels are high
Cortisol increases fear
Serotonin tends to inhibit violent impulses
Increased testosterone levels in women, increased importance of social status, and decreased ability to recognize angry faces

38. Attack Behaviors (cont’d.)
Testosterone alters the way people respond to stimuli
May increase the response of the amygdala to angry expressions
Decreases ability of the cerebral cortex to identify and regulate emotion

39. Attack Behaviors (cont’d.)
Studies also suggest a connection between aggressive behavior and low serotonin release.
Turnover is the amount of a neurotransmitter that is released, reabsorbed and resynthesized by neurons
Valzelli’s (1973) study with male juvenile mice found that social isolation decreased serotonin turnover and increased aggressive behavior

40. Attack Behaviors (cont’d.)
5-hydroxyindoleacetic acid (5-HIAA) is a serotonin metabolite found in the cerebrospinal fluid, blood, and urine that allows researchers to infer turnover rate
High levels of 5-HIAA imply much serotonin release and turnover
Research with monkeys has demonstrated that low levels of 5-HIAA increases the probability of attack on larger monkey
Few survived past age six

41. Attack Behaviors (cont’d.)
Monkeys with high levels of 5-HIAA were more likely to survive
Evolution seems to select for an intermediate amount of anxiety and aggression
Evolution might also select for high aggressive behaviors
May die young, but are more likely to achieve a dominant position within the troop

42. Attack Behaviors (cont’d.)
In human studies, low serotonin turnover has been linked to:
People with a history of violent behavior and violent crime
People who attempt suicide by violent means
Recurrent violent behaviors
A simple blood test does not enable the reliable identification
Not applicable in the “normal” population

44. Attack Behaviors (cont’d.)
Changes in diet can alter serotonin synthesis
It would seem prudent for anyone with aggressive or suicidal tendencies to reduce consumption of aspartame and maize (American corn)

45. Fear and Anxiety
Proneness to approach, avoidance, and anxiety varies with the situation
Amygdala is one of the main areas for integrating both environmental and genetic influences and then regulating current levels of anxiety

46. Fear and Anxiety (cont’d.)
The startle reflex is the extremely fast response to unexpected loud noises
Found in young infants
Auditory information stimulates an area of the pons that commands the tensing of the neck and other muscles (because neck is so vulnerable to injury)
Information reaches the pons within 3 to 8 milliseconds after
The startle response occurs within two-tenths of a second
See a video:

47. Fear and Anxiety (cont’d.)
Current mood or situation can modify the reaction
Startle reflex is more strong if already tense
Cells in the amygdala receive information from pain, vision, and hearing circuits
Axons extend to areas in the midbrain that relay information to the nucleus in the pons
The relay controls the startle reflex
See a video for an example of a startle response:

49. Fear and Anxiety (cont’d.)
Output from the amygdala to the hypothalamus controls autonomic fear responses such as increased blood pressure.
Axons extending from the amygdala to the prefrontal cortex regulate approach and avoidance responses

50. Fear and Anxiety (cont’d.)
Damage to the amygdala interferes with:
The learning of fear responses
Retention of fear responses previously learned
Interpreting or understanding stimuli with emotional consequences
When Toxoplasma gondii parasites enters a rat, it damages the amygdala. The rat fearlessly approach a cat, and get eaten by a cat.

51. Fear and Anxiety (cont’d.)
In the early 1900s, studies of monkeys with Kluver-Bucy syndrome illustrated the effects of amygdala damage
Monkeys with this syndrome are calm and placid and display less than normal fear of snakes and larger, more dominant monkeys
Also alters social behaviors in that they have decreased ability to interpret threat gestures
Non-damaged monkeys with a vigorously active amygdala show fear to noise/intruder

52. Fear and Anxiety (cont’d.)
fMRI studies suggest the amygdala responds strongly to emotional stimuli/facial expressions
Activity is strongest when the meaning is unclear and requires some processing
Responds more strongly to an angry face directed toward the viewer and frightened faces directed elsewhere
Amygdala also responds to stimuli not consciously perceived

54. Fear and Anxiety (cont’d.)
People’s tendency for anxiety remains fairly consistent over time
College students who reported more unpleasant emotions showed higher amygdala response than others one year later
Soldiers with initial high levels of amygdala response showed more combat stress
People with a greater startle response show more support for military and guns. People with a highly reactive amygdala are likely to perceive dangers, and therefore to support strong protection against those dangers.

56. Fear and Anxiety (cont’d.)
In humans, damage to the amygdala does not result in the loss of emotion
Damage to the amygdala impairs the processing of emotional information
People with damage recognize the cognitive aspects of emotions, but not the feeling aspect

57. Fear and Anxiety (cont’d.)
Urbach-Wiethe disease: rare genetic condition that causes calcium to build up into the amygdala until it wastes away
Case study of SM
Experiences fearlessness that is dangerous to her: robberies at gunpoint, physical assaults, no inhibition when strangers approach
Reports feeling angry but not afraid in response to these incidents

60. Fear and Anxiety (cont’d.)
Amygdala damage also affects the ability to recognize emotions specifically in photographs or pictures
Effect is particularly strong for fear or disgust
Amygdala damage does not affect the ability to recognize fear in real life
Attention to certain aspects of the face (eyes versus mouth) may account for the difference

62. Anxiety Disorders (cont’d.)
Panic disorder: frequent periods of anxiety and occasional attacks of rapid breathing, increased heart rate, sweating, trembling, etc.
More common in women than men; more common in adolescents and young adults
Possible genetic component
Seems to be linked to abnormalities in the hypothalamus
Decreased GABA, increased orexin (maintaining wakefulness and activity)

63. Anxiety Disorders (cont’d.)
Drugs that increase GABA activity inhibit panic
Benzodiazepines are the most commonly used anti-anxiety drugs
Examples: diazepam (Valium), alprazolam (Xanax)
Benzodiazepines bind to the GABAA receptor, and facilitate the effects of GABA
Benzodiazepines exert their effects in the amygdala, hypothalamus, midbrain, and other areas

65. Anxiety Disorders (cont’d.)
Alcohol as an Anxiety Reducer
Ethyl alcohol has behavioral effects similar to benzodiazepines
Alcohol enhances GABA effects

66. Concepts of Stress
Hans Selye (1979) defined stress as the non-specific response of the body to any demand made upon it
Threats on the body activate a general response to stress called the general adaptation syndrome

67. Concepts of Stress (cont’d.)
The general adaptation syndrome:
Alarm stage: increased sympathetic nervous system activity
Resistance stage: sympathetic response declines; adrenal cortex releases cortisol and other hormones; prolonged alertness
Exhaustion stage: occurs after prolonged stress; inactivity, vulnerability, and decreased energy, tiredness

68. Concepts of Stress (cont’d.)
Sapolsky (1998) argues that the nature of today’s crises are more prolonged (such as advancing in a career, paying a mortgage)
Accounts for widespread stress-related illnesses and psychiatric problems in industrial societies
Long-term, inescapable issues activate the general adaptation syndrome which is harmful to our health over time

69. Stress and the Hypothalamus-Pituitary-Adrenal Cortex Axis
Stress activates two systems in the body:
The sympathetic nervous system: “fight or flight” response that prepares the body for brief emergency responses
The HPA axis: the hypothalamus, pituitary gland, and adrenal cortex

71. Stress and the Hypothalamus-Pituitary-Adrenal Cortex Axis (cont’d.)
The HPA axis becomes the dominant response to prolonged stressors
Activation of the hypothalamus induces the pituitary gland to secrete adrenocorticotropic hormone (ACTH)
ACTH stimulates the adrenal cortex to secrete cortisol
Cortisol helps to mobilize energies to fight a difficult situation

72. Stress and the Hypothalamus-Pituitary-Adrenal Cortex Axis (cont’d.)
The effects of stress depend on amount and duration
Brief or moderate stress improves attention and memory formation performance on relatively simple tasks
It impairs performance that requires complex, flexible thinking

73. Stress and the Hypothalamus-Pituitary-Adrenal Cortex Axis (cont’d.)
In response to a stressful experience, the nervous system activates the immune system
Prolonged stress response is damaging to the body
Prolonged increase of cortisol detracts from the synthesis of proteins of the immune system
Prolonged stress of longer than a month significantly increases the likelihood of illness

74. Stress and the Hypothalamus-Pituitary-Adrenal Cortex Axis (cont’d.)
Prolonged stress can also be harmful to the hippocampus and can affect memory
Cortisol enhances metabolic activity in the body
When metabolic activity is high in the hippocampus, the neurons are more sensitive to damage by toxins or over-stimulation
Stress also impairs the production of new hippocampal neurons

75. Stress and the Hypothalamus-Pituitary-Adrenal Cortex Axis (cont’d.)
A variety of ways exist to reduce stress or control our response to it:
Breathing routines, exercise, meditation, distraction, and addressing issues
Social support from a loved one helps to reduce stress
Reduces response in several brain areas, including the prefrontal cortex

76. Post-traumatic Stress Disorder
Post-traumatic stress disorder (PTSD) occurs in some people after terrifying experiences and includes the following symptoms:
Frequent distressing recollections
Nightmares
Avoidance of reminders of the event
Exaggerated arousal in response to noises and other stimuli

77. Post-traumatic Stress Disorder (cont’d.)
Most PTSD victims have a smaller than average hippocampus
Severe stress elevated the cortisol secretion and high cortisol damaged the hippocampus
PTSD victims show lower than normal cortisol levels after the trauma
People with low cortisol levels may be ill-equipped to combat stress and more prone to the damaging effects of stress
The amygdala is essential for the extreme emotional impact that produces PTSD