Download Attack and Escape Behaviors

Chapter 12
Emotional Behaviors
Module 11.1:
What Is Emotion?
Module 11.2:
Attack and Escape
Behaviors
Module 11.3:
Stress and Health
What is Emotion?
•
An emotional state
has three aspects:
1. Cognition
(assessment of
situation: “This is
dangerous.”)
2. Feelings (“I feel
scared”—requires
labeling)
3. Action (involves
physical response,
such as running
away)
Common Sense View
What is Emotion?
• Action, or “readiness for action” is a product of the
autonomic nervous system (ANS).
• James-Lange theory (1884): autonomic arousal and
skeletal action occur first, then come feelings/emotions.
• The emotion that is felt is the label that we give the arousal
of the organs and muscles.
What is Emotion?
•
According to the
James-Lange theory:
1. People with a weak
autonomic or
skeletal response
should feel less
emotion.
2. Increasing one’s
response should
enhance an
emotion.
What is Emotion?: Evidence
Supporting the James-Lange Theory
• People with “pure autonomic
failure” report feeling emotion less
intensely.
– Pure autonomic failure - output
from the autonomic nervous
system almost entirely fails.
• Botulinum toxin (BOTOX): blocks
transmission at synapses and
nerve-muscle junctions, resulting
in temporary paralysis, resulting
in weaker than usual emotional
responses
What is Emotion?: Evidence
Supporting the James-Lange Theory
• 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
What is Emotion?: Evidence Refuting
the James-Lange Theory
Research indicates that paralyzed
people report feeling emotion to the
same degree as prior to their injury
• Contradictory research suggests other factors are involved
in the perception of emotion.
What is Emotion?: Basic Emotions
• Facial expressions are just one source of information about
emotion
• Research indicates that facial expressions, body posture,
tone of voice all convey emotional meaning
What is Emotion?
• Emotional experiences arouse many areas of the brain.
• The limbic system has 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.
What is Emotion?
• Emotions tend not to be localized in specific parts
of the cortex.
• A single emotion increases activity in various parts
of the brain.
What is Emotion?
• Inactivation of the medial frontal cortex appears to
impair the ability to recognize angry expression.
What is Emotion?
• Insular cortex
– strongly activated when
experiencing disgust
– primary taste cortex
– reacts to frightening
stimuli as well.
What is Emotion?
• The two hemispheres of the brain play different
roles in emotion.
• Behavioral Inhibition
System (BIS): associated
with increased activity of
the frontal and temporal
lobes of the right
hemisphere
– Increases attention and
arousal
– Inhibits action
– Stimulates emotions
such as fear and disgust
What is Emotion?
• Behavioral Activation
System: increased
activity of left
hemisphere frontal and
temporal areas
– associated with
“approach”
– marked by low to
moderate arousal
– registers happiness
or anger
What is Emotion?
• Differences in prefrontal cortex activity relates to personality.
• People with
greater
activity in
the left
hemisphere
tend to be
happier,
more outgoing and
friendlier.
• People with
greater right
hemisphere
activity tend
to be
socially
withdrawn,
less satisfied
with life, and
prone to
unpleasant
emotions.
What is Emotion?
• 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.
What is Emotion?
• One major function of emotion is to help us make decisions.
• Failure to anticipate the unpleasantness of an event can
lead to bad decision making.
• Low autonomic arousal is correlated with making logical
moral decisions
Attack and Escape Behaviors
• Pain, threat or other
unpleasant stimuli usually
trigger an attack behavior.
• Attack behaviors are
associated with increased
activity in the corticomedial
area of 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.
Attack and Escape Behaviors
• Twins studies suggest genetic
contribution to the likelihood of
violent behavior.
• Smoking cigarettes while pregnant is
correlated with violent behavior in
offspring.
• The effect is particularly strong if the
mother smoked and also had
complications during pregnancy.
Attack and Escape Behaviors
• Environmental factors can
combine with genetic factors to
influence behavior.
• Adopted children have the
highest probability of violent
behavior if the biological parent
has a criminal record and there
is discord in the adopted family
household.
• A biological predisposition
alone, or a troubled adoptive
family by itself, produces only
moderate effects.
Attack and Escape Behaviors
• On average, males engage in more aggressive and violent
behaviors than do females.
• Male aggressive behavior is influenced by the hormone
testosterone.
• Research shows that men with the highest rates of violent
behavior also have slightly higher testosterone levels.
Attack and Escape Behaviors
• Studies suggest a connection
between aggressive behavior
and low serotonin release.
• Turnover is the amount of
release and resynthesis of a
neurotransmitter by
presynaptic neurons.
• In human and animal studies,
low serotonin turnover has
been linked to:
– violent behavior and violent
crime
– suicide by violent means
Attack and Escape Behaviors
• “Fear” is associated with a
strong tendency to escape
from an immediate threat.
• “Anxiety” is a general
sense that something
dangerous might occur.
– Not necessarily
associated with the
desire to flee.
Attack and Escape Behaviors
• The startle reflex is the
extremely fast response
to unexpected loud
noises.
– found in young
infants and thus
unlearned.
• Auditory information
stimulates an area of
the pons that
commands the tensing
of the neck and other
muscles.
Attack and Escape Behaviors
• Stimuli previously associated
with the startle response
enhances the startle
response.
– Cells in the amygdala are
responsible.
• 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 enhances the
startle reflex.
Attack and Escape Behaviors
• Output from the
amygdala to the
hypothalamus
controls autonomic
fear responses.
• Axons extending from
the amygdala to the
prefrontal cortex
regulate approach
and avoidance
responses.
Attack and Escape Behaviors
• fMRI studies of humans
suggest the amygdala
responds strongly to emotional
stimuli and facial expressions.
– Activity is strongest when
the meaning is unclear and
requires some processing.
– With some exceptions,
looking at happy faces
activates the amygdala only
weakly.
• Amygdala also responds to
stimuli not consciously
perceived.
Attack and Escape Behaviors
Damage to the
amygdala interferes
with:
• learning of fear
responses
• retention of fear
responses
previously learned
• interpreting or
understanding
stimuli with
emotional
consequences
Attack and Escape Behaviors:
Anxiety Disorders
• Damage to the amygdala
impairs the processing of
emotional information when
the signals are subtle or
complicated.
• Amygdala damage affects the
ability to judge
“trustworthiness” in people.
• People with amygdala
damage focus on emotional
stimuli the same as irrelevant
stimuli or details.
Attack and Escape Behaviors
• People with overactive amygdalae may experience anxiety:
– physical distress, including muscle tension, heart
palpitations, sweating, rapid breathing
– emotional distress, including worry, etc.
• Panic Disorder: episodes of extreme anxiety
• Generalized Anxiety Disorder: recurrent/continuous anxiety
with no identifiable cause
• Phobias: fear of a specific place, thing, or situation
• Post-traumatic Stress Disorder (PTSD): anxiety that occurs
after experiencing a traumatic event
Attack and Escape Behaviors
• Excessive fear and anxiety disorders
are associated with hyperactivity in the
amygdala
• Drugs intended to control anxiety alter
activity at amygdala synapses.
• The main excitatory neuromodulator in
the amygdala is CCK, and the main
inhibitory transmitter is GABA.
– Injections of CCK-stimulating drugs
into the amygdala enhance the
startle response.
– Drugs that increase GABA activity
decrease panic.
GABA =STOP
CCK/Orexin=GO
Attack and Escape Behaviors
• Benzodiazepines are the most commonly used anti-anxiety
drugs (anxiolytics or tranquilizers).
• Benzodiazepines bind to the GABAA receptor complex, and
facilitate the effects of GABA.
• Benzodiazepines exert their effects in the amygdala,
hypothalamus, midbrain, and other areas.
Attack and Escape Behaviors
• Ethyl alcohol has
behavioral effects
similar to
benzodiazepines.
• Alcohol enhances
GABA effects.
Stress and Health
• Behavioral medicine
emphasizes the effects
of diet, smoking,
exercise, stressful
experiences, and other
behaviors on health.
• Emotions and other
experiences influence
illness and pattern of
recovery.
Stress and Health
• Hans Selye (1979) defined stress as the nonspecific 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.
Stress and Health
The General Adaptation Syndrome:
• Alarm stage - characterized by
increased sympathetic nervous
system activity.
• Resistance stage - sympathetic
response declines, the adrenal
cortex releases cortisol and
other hormones that enable the
body to maintain prolonged
alertness.
• Exhaustion stage - occurs after
prolonged stress and is
characterized by inactivity and
decreased immune system.
Stress and Health
Stress activates two
systems in the body:
1. The autonomic
nervous system “fight or flight”
response that
prepares the body
for brief emergency
responses
2. The HPA axis - the
hypothalamus,
pituitary gland, and
adrenal cortex.
Stress and Health
• 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 enhances metabolic
activity and elevates blood
levels of sugars and other
nutrients to mobilize energies.
Stress and Health
• Prolonged increased cortisol
levels impair the immune system.
• The immune system consists of
cells that protect the body against
viruses and bacteria.
– Leukocytes – white blood cells.
Stress and Health
• During an infection, leukocytes
and other cells produce small
proteins called cytokines.
– Combat infection and
communicate with the brain
to inform of illness.
• Cytokines in the brain produce
symptoms of illness.
– Fever, sleepiness, lack of
energy etc.
– Sleep and inactivity are the
body’s way of conserving
energy to fight illness.
Stress and Health
• Psychoneuroimmunology is
the study of the relationship
between the nervous system
and the immune system.
• Deals with the way in which
experiences, especially
stressful ones, alter the
immune system.
• Also deals with how the
immune system influences
the central nervous system.
Stress and Health
Prolonged stress response
is damaging to the body:
• Increase of cortisol
detracts from the
synthesis of proteins of
the immune system.
• Cortisol enhances
metabolic activity in the
body.
• Significantly increases
the likelihood of illness,
including autoimmune
disease (immune
system attacks normal
cells)
Stress and Health
• Prolonged stress response is
damaging to the body:
– Can be harmful to
hippocampus and can
affect memory.
– When metabolic activity is
high in the hippocampus,
the neurons are more
sensitive to damage by
toxins or over-stimulation.
– Stress also impairs the
adaptability and the
production of new
hippocampal neurons.
Stress and Health
• Posttraumatic 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
Stress and Health
• Studies have revealed
most PTSD victims have
a smaller than average
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.
Stress and Health
• There are many ways to combat and manage stress!