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Biopsychology, 8th Edition
by John P.J. Pinel
Prepared by Jeffrey W. Grimm
Western Washington University
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Chapter 17
Biopsychology of Emotion,
Stress, and Health
Fear, the Dark Side of Emotion
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Biopsychology of Emotion:
Introduction

Phineus Gage


Why would a tamping iron through the skull lead
to dramatic changes in personality?
Damage to the medial prefrontal lobes

Site of planning and emotion
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FIGURE 17.1 A reconstruction of
the brain injury of Phineas
Gage. The damage focused on
the medial prefrontal lobes.
(Based on Damasio et al., 1994.)
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Darwin’s Theory of the
Evolution of Emotional
Expression


Expressions of emotion evolve from
behaviors that indicate what an animal is
likely to do next
If emotional signals are beneficial, they will
evolve to more effectively communicate and
may lose their original meaning
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Evolution of Emotional
Expression Continued


Opposite messages are often signaled by
opposite movements – “principle of
antithesis”
Threat displays, for example, are beneficial –
intimidate victims without the costs and risks
for fighting
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Theories of Emotion

James-Lange
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Cannon-Bard
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Stimulus triggers autonomic/skeletal response
which triggers emotion
Autonomic/skeletal response necessary for
emotion
Stimulus triggers autonomic/skeletal response
and emotion
Autonomic/skeletal response independent of
emotion
Both are wrong
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FIGURE 17.3 Four ways of thinking
about the relations among the
perception of emotion-inducing
stimuli, the autonomic and somatic
responses to the stimuli, and the
emotional experience.
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Sham Rage



Decorticated cats exhibit extreme and
unfocused aggressive responses
Hypothalamus must be intact
Perhaps hypothalamus is needed for
expression of aggression and cortex serves
to inhibit and direct responses
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Limbic System and Emotion

Papez proposed emotional circuit (limbic
system) that includes hypothalamus
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FIGURE 17.4 The location of the major limbic
system structures. In general, they are arrayed
near the midline in a ring around the thalamus.
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Kluver-Bucy Syndrome




Rare cerebral neurological disorder
Major symptoms – urge to put objects into
mouth, memory loss, extreme sexual
behavior, placidity, visual distractibility
Results from bilateral damage to anterior
temporal lobes
First seen in monkeys, then other species
(including humans)
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Emotions and the Autonomic
Nervous System (ANS)

Two important questions



Which patterns of ANS activity are associated with
specific emotions?
Are ANS measures effective on polygraph (“lie
detector”)?
There is not a separate ANS profile for each
emotion
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Polygraphy


Lie detection is really emotion detection
Control-question technique

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Physiological response to a target question compared
with response to control question
Success rate in studies is about 80%
Guilty knowledge technique


Merely ask a question that only the culprit would know
the answer to
Success rate in distinguishing guilty vs. innocent is
88% in one study
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Emotions and Facial
Expression


The meanings of facial expressions appear to
be universal
Six primary emotions

Naturally occurring expressions are usually variations
or combinations of the basic ones
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Emotions and Facial
Expressions


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Facial feedback hypothesis – smiling makes
you happier; facial muscles influence
emotional experience
Microexpressions – brief facial expressions
reveal true feelings; may break through false
ones
Different muscles involved in fake and real
smiles
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Fear, Defense, and Aggression

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Fear – emotional reaction to threat
Aggressive behaviors – designed to threaten or
harm
Defensive behaviors – designed to protect from
threat or harm (motivated by fear)
Social aggression – unprovoked attacks on
members of one’s own species to establish
dominance
Defensive attack – aggressive behavior, as
when cornered
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Types of Aggressive and
Defensive Behaviors

Colony-intruder model of aggression and
defense in rats
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Observation of cats and mice
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
Study interaction between alpha male of an
established colony with a small male intruder
Cat “play” with prey is actually a combination of
attack and defense behaviors
Target-site concept – aggressive behaviors
designed to attack specific sites on body,
defensive to protect specific sites
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Aggression and Testosterone (T)

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Nonprimates – T release around birth of male
rats prepares them for T-activated social
aggression at maturity
T increases or has no effect on social
aggression, depending on species; castration
decreases or has no effect on social
aggression in same species
In humans, social aggression does not
increase along with higher T levels at puberty
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Aggression and Testosterone
Continued

Social aggression in humans



Does not decrease with castration or increase with
testosterone injections
Violent criminals and aggressive male athletes may have
high testosterone levels, but may be result (not cause) of
aggressive behavior
Possible sources of discrepancies in human studies


Measured blood testosterone level; should measure brainpart testosterone levels
Failure of researchers to distinguish between social
aggression (testosterone-related, for establishing
dominance) and defensive aggression (e.g., when
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Neural Mechanisms of Fear
Conditioning

Fear conditioning


Pair a neutral stimulus (e.g., a tone) with an
aversive stimulus (e.g., a shock)
Present the tone later and the animal will show a
conditioned fear response

Usually a defensive behavior
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Amygdala and Fear
Conditioning


Lesions of the amygdala block fear
conditioning
The amygdala receives input from all sensory
systems


Appears to be responsible for adding emotional
significance to another stimulus
Amygdala projects to brainstem regions that
control emotional behavior output
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FIGURE 17.9 The structures that are thought to
mediate the sympathetic and behavioral responses
conditioned to an auditory conditional stimulus.
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Contextual Fear Conditioning
and the Hippocampus

Pair an aversive stimulus with the context
instead of with a discrete stimulus


Hippocampus is linked to spatial memory
Effect of bilateral hippocampal lesions on
contextual fear conditioning

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Before training – prevents conditioning
Shortly after training – blocks retention of conditioning
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Amygdala Complex and Fear
Conditioning


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Current synthesis of findings indicates that the
lateral amygdala is most critical in conditioned
fear
In addition, conditioned fear is suppressed by
the prefrontal cortex inhibiting the lateral
amygdala
The hippocampus mediates conditioned fear
learning by informing the lateral amygdala about
the context of the fear-related event
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Stress and Health

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Stress – reaction to harm or threat
Stressors – stimuli that cause stress
Chronic psychological stress – most clearly
linked to ill health
In the short-term, stress is adaptive; in the
long-term, it is maladaptive
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The Stress Response

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Stress triggers stress hormone: anterior-pituitary adrenal-cortex system (glucocorticoids,
epinephrine, and norepinephrine) and
cytokines (causing inflammation and fever)
Selye neglected sympathetic nervous system
Individual differences, such as attitude, affect
the magnitude of the stress response

Example: women awaiting surgery who were
“certain” they did not have breast cancer had
milder stress than others
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FIGURE 17.10 The two-system
view of the stress response.
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Animal Models of Stress


Some early models used levels of stress that
might not have a human equivalent
Some more recent models use social
stresses

For example, subordination stress
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Psychosomatic Disorders: The
Case of Gastric Ulcers

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Gastric ulcers – lesions of stomach lining and
duodenum
More common in those who are stressed;
readily created in the animal lab
Ulcers are caused by a bacteria – stress
appears to makes the body vulnerable to this
bacteria
75% of healthy subjects have the bacteria
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Psychoneuroimmunology

Study of the interaction of psychological
factors, the nervous system, and the
immune system
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Immune System

Divisions of the mammalian immune system
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Innate immune system
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First line of defense
Attacks generic classes of pathogens
Adaptive immune system
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Targets specific pathogens identified by their
antigens
Has memory (the basis of effectiveness of
vaccination)
Cytokines activate lymphocytes (white blood cells)


Cell-mediated (T lymphocytes)
Antibody-mediated (B lymphocytes)
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FIGURE 17.12 Two adaptive barriers to infection: Cell-mediated immunity and antibody-mediated
immunity. In cell-mediated immunity, microorganisms or body cells that they have invaded are
killed by T cells; in antibody-mediated immunity, microorganisms are killed by antibodies
produced by B cells.
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What Effect Does Stress Have
on Immune Function:
Disruptive or Beneficial?

Effects of stress on immune function
depends on the kind of stress



Acute stressors improve immune function
Chronic stressors impair immune function
Many ways that stress can impact immune
function

Effects of stress can be good (adaptive and
healthful), bad, or mixed
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Early Experience of Stress

Stress or mistreatment early in life may cause
brain and endocrine abnormalities later in life


Rat pups handled by researchers had more
adaptive stress response in adulthood (less
circulating glucocorticoids following stress),
probably due to less negative feedback from
hippocampal glucocorticoid receptors
A good example of epigenetic (“not of the
genes”) transmission: fearful, poor-grooming
mothers raise daughters who become fearful,
poor-grooming mothers
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Stress and the Hippocampus


Hippocampus has many glucocorticoid
receptors
Following stress
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Dendrites of pyramidal cells are shorter and less
branched
Adult neurogenesis of granule cells reduced
Effects blocked with adrenalectomy;
produced with corticosteroids
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Brain Mechanisms of Human
Emotion: Cognitive
Neuroscience

Three main points have advanced the
understanding of brain mechanisms of emotion



Brain activity associated with each human emotion is
diffuse
There is usually motor and sensory regional activity
along with an emotional response
Brain activity for experienced, imagined, or observed
emotion is similar
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FIGURE 17.13 A functional MRI scan illustrates areas of increased activity in
primary motor cortex and premotor cortex when volunteers watched facial
expressions of emotion. The same areas were active when the volunteers
made the expressions themselves. (From Carr et al., 2003.)
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Amygdala in Human Emotion


Early theories of emotion were general
theories (e.g., limbic system theory – limbic
system plays a role in all emotions)
Recent discoveries


From brain imaging, amygdala activity is
correlated with fear (especially social fear) and
certain other negative emotions
Urbach-Wiethe disease (calcification of
amygdala) causes loss of facial expression and
loss of recognition of fear
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Medial Prefrontal Lobes and
Human Emotion

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Includes medial portions of the orbitofrontal
cortex and cingulate cortex
Site of emotion-cognitive interaction, especially
cognitive suppression of emotional reactions
Possible roles in comparison of outcome and
expectancy, guiding behavior based on recent
experience, response to social rejection
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Lateralization of Emotion

Two theories

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Right-hemisphere model – the right hemisphere is
dominant for all aspects of emotion
Valence model – the right hemisphere specializes
in negative emotions
Both theories are probably too general
Strong evidence for lateralization for particular
structures and emotions
Males may be more lateralized than females
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FIGURE 17.15 The asymmetry of facial expressions. Notice that the expressions are
more obvious on the left side of two well-known faces: those of Mona Lisa and Albert
Einstein. The Einstein face is actually that of a robot that has been programmed to make
natural facial expressions.
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Individual Differences in the
Neural Mechanisms of Emotion


Most (but not all) of nine patients with bilateral
amygdalar lesions had difficulty recognizing
fear in facial expressions (Adolphs and
colleagues, 2003)
Personality differences: both high extraversion
and high neuroticism healthy subjects showed
higher amygdalar activity while viewing fearful
faces; only extraverts showed higher
amygdalar activity while viewing happy faces
(Canli and colleagues, 2002)
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