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 19 th century  Cannon/Bard theory, early 20 th 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) –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) –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  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: –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