Transcript Emotions, Stress and Health

EMOTIONS
STRESS & HEALTH
DEFINING EMOTIONS
 Emotions constitute multiple responses
– Behavioral (Actions)
– Autonomic (Physiological)
– Hormonal (Physiological)
– Internal Subjective Experience
(Psychological)
Study Objective #1
HISTORICAL LANDMARKS IN THE
STUDY OF EMOTION
 Phineas Gage Case – 1848
 Darwin’s Publication On the Expression of
Emotion in Man and Animals, 1872
 James/Lange theory, late 19th century
 Cannon/Bard theory, early 20th century
 Sham rage experiments by Bard, 1929
 Limbic System involvement in emotion as
depicted by Papez, 1937
 Kluver-Bucy Syndrome described, 1939
THEORIES OF EMOTION
 Darwin
– Comparative studies of emotional expression
– Evolutionary theory of emotion
 James-Lange Theory
– emphasis on physiological changes
– stimulus-->autonomic response-->emotion
 Canon-Bard Theory
– emphasis on central processes
– Stimulus produces simultaneous autonomic and
emotional reactions that are not necessarily
causally related.
THEORIES OF EMOTION
Study Objective #2
THEORIES OF EMOTION
 Schachter’s Cognitive Theory
– The experience of emotion is influenced by
cognitive appraisal/interpretation of physiological
changes.
– Stimuli produce nonspecific arousal that are
cognitively labeled based on external cues.
 Schachter and Singer (1962)
– Epinephrine injections were given to participants
who then witnessed either a happy or angry
confederate.
– The environmental context influenced participant’s
interpretation/appraisal of the autonomic arousal.
NEUROBIOLOGY OF EMOTION
 Decorticate rage (sham rage)
– Bard (1929) studied decorticate cats.
– Aggressive responses were poorly coordinated and
not directed at particular targets
– Bard concluded that the hypothalamus is critical for
the expression of aggressive responses and the
cortex is responsible for inhibiting and directing
those responses.
 Kluver-Bucy Syndrome (1939)
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lesions of anterior temporal lobes/amygdala
tameness, lack of fear
hyperorality and hypersexuality
Similar syndrome has been observed in humans
with amygdala damage.
Study Objective #3
NEUROBIOLOGY OF EMOTION
 LIMBIC SYSTEM
(Papez’s circuit)
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amygdala
hippocampus
fornix
septum
hypothalamus
cingulate gyrus
mammillary bodies
Study Objective #4
NEUROBIOLOGY OF EMOTION
 Autonomic Nervous System
– Emotional Specificity??
 Uses of polygraphy
– Control-question technique
– Guilty-knowledge technique
AGGRESSION
 FORMS OF AGRESSION
– Offensive Behaviors
 Predatory (related to feeding)
 Social (establishing, maintaining social hierarchy or
territory, related to reproduction)
– Defensive Behaviors
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Intraspecific defense
Defensive attacks
Freezing and Flight
Maternal Defensive Behaviors
Risk Assessment
Defensive Burying
ANDROGENS AND AGGRESSION
 Castration reduces aggressive behavior in
male rodents.
– Testosterone injections reinstate this behavior.
 Studies in human males are less convincing.
– Mixed results
– Correlational studies --> problematic interpretation
 Testosterone and Social dominance
Study Objective #8
ANDROGENS AND AGGRESSION
Study Objective #8
SEROTONIN & AGGRESSION
 Serotonin levels show negative correlations
with aggression
– Destruction of 5-HT axons in forebrain facilitates
aggressive attack.
– 5-HIAA levels are lower in more aggressive
animals (linked to risky behavior).
– Diminished 5-HIAA levels in CSF of people with
history of violence and impulsive aggression.
 SSRIs and violent acts
– mostly anecdotal reports and media hype
– SSRIs actually decrease aggressive behavior.
Study Objective #7
FEAR CONDITIONING
Study Objective #5
NEUROBIOLOGY OF FEAR
 AMYGDALA
– Subdivided into several nuclei.
 Central Nucleus, Lateral Nucleus
– Electrical/chemical stimulation of the
amygdala elicits emotional responses
– Amygdala lesions disrupt wide range of
emotional behaviors and physiological
responses
– Lesions of the central nucleus and the lateral
nucleus abolish conditioned fear.
NEURAL CIRCUITRY OF FEAR
e.g., Freezing HR/BP Cortisol
Study Objective #6
NEURAL CIRCUITRY OF FEAR
Study Objective #6
STRESS & HEALTH
 Defining Stress
– Cluster of physiological responses to threat or
harm
 Both physical and psychological stressors produce
similar patterns of physiological changes.
 Acute stress is adaptive.
 Chronic stress is maladaptive.
– Stress response
 First described by Hans Selye, 1950s
 Activation of Hypothalamus-Anterior Pituitary-Adrenal
Cortex System (HPA axis)
– Feedback loop involving actions of CRH, ACTH, and cortisol
HPA axis
Study Objective #9
STRESS & HEALTH
 Hormonal Responses to Stress
– Glucocorticoids (e.g., cortisol) from adrenal
cortex
 assists with metabolism to provide energy
 increases blood flow
 stimulates behavioral responsiveness
– Sympathetic activation (norepinephrine) and
epinephrine from adrenal medulla
 Epinephrine influences glucose metabolism.
 Catecholamines increase blood flow to muscles
by increasing heart output.
Study Objective #10
STRESS RESPONSES
HORMONAL RESPONSES TO
SOCIAL STRESS
Study Objective #13
ADAPTATION TO STRESS
 General Adaptation Syndrome (Selye)
– Alarm Stage: fight or flight reaction
– Resistance: adaptation, immune responses
– Exhaustion: energy depletion, immune system
suppression
ADAPTATION TO STRESS
STRESS & HEALTH
 Psychoneuroimmunology
– CNS influences on immune function (through
ANS and HPA axis)
– Immune system influences on CNS (antibodies
and cytokines influence brain activity)
Study Objective #11
PSYCHONEUROIMMUNOLOGY
STRESS AND HEALTH
 Prolonged elevations in stress hormones
may cause deleterious effects:
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prolonged inc. bp ---> heart disease
muscle tissue damage
growth retardation
inhibition of inflammatory responses, slower healing,
immunosuppression
– increased cell death in hippocampus (may accelerate
aging processes)
 Stress related diseases
– Gastric Ulcers
– Cancers
– Heart Disease
Study Objective #12
STRESS AND HEALTH
Study Objective #12