Stress & Emotion June 24, 2014

1. Stress & EmotionJune 24, 2014

2. Emotion

3. What is Emotion? • As component of personality, decision making • Not simple states of mind • Ex. What does it mean to be “happy”? Biopsychologists look at emotion in context - component behaviors in particular situations

4. Evolution of Emotion Why would emotion have evolved? • Conserved across species • Communication w/in and between species • Expressions/displays assoc. w/ emotional states • Dominance, submission

6. Basic Human Emotions • Identifying/assoc. facial expressions w/ emotions • Can fluctuate (ex. threat in pregnancy) • 6 “primary” emotions based on typical expressions • Happiness, sadness, anger, disgust, fear, surprise • Others are “combinations” • Facial patterns not learned • Smile/frown universal

8. Biological Basis of Emotion

9. Autonomic System • Sympathetic arousal, response to threat How does a “lie detector” work? • Measure “emotional state” in response to cues/info • Heart rate, skin response, respiration

10. Limbic System • Emotional context • Connection w/ memory • Interaction w/ hypothalamus (autonomic control, motivation), frontal cortex (decision making, perception of emotional state)

11. Amygdala • Limbic nuclei – memory, emotional processing • Removal - Kluver-Bucy syndrome • Increased, undirected consumption • Inappropriately directed sexual behavior • Perseveration • Oral investigation of objects • Lack of fear

12. Frontal Cortex • Emotional context • Situation, likely consequences • Decision making • Prefrontal – emotional reactions, social rejection • Mood, personality, experience of “feeling” state – what we describe as emotion • Affect: the experience or feeling of emotion

13. Human Affect We tend to see emotion as something special – but it is a behavior like any other, a result of the brain’s interpretation of the situation

14. Human Affect • No “site” of emotion • Complex interaction of brainstem, limbic responses w/ diffuse areas throughout cortex • Modulated by 5-HT, DA • Extensive networks • Experiencing/imagining – role in empathy

15. Human Affect • Right hemisphere dominance - production, recognition of facial expressions • Much is still unknown • How to define emotion • Experiences across species

16. Theories of Emotion

17. Previous Theories James-Lange: sensory stimulus triggers appropriate autonomic response, interpreted as particular emotion Dependent on autonomic feedback Cannon-Bard: stimuli excites both feeling of emotion and expression of emotion (in parallel) Independent of autonomic system

18. Modern Theories • Something in between • Autonomic not necessary (ex. spinal cord injury) • Autonomic response caninfluence emotional experience • Facial expression can influence mood • Complex interaction - perception, feeling, physiological reaction

20. Models of Fear and Aggression

21. Fear Emotional response to perceived threat Motivates defensive behaviors (protection/avoidance of harm)

22. Fear Postures against aggression Defensive attack Freezing/fleeing Maternal defense Risk assessment (scanning the environment) Defensive burying

23. Fear • Hippocampus – associate stimuli w/ environment • Amygdala - fear conditioning (assoc. w/ previously neutral situations), emotional significance • Perception of fear?

24. Aggression • Intent to threaten or harm • Motivates aggressive behaviors • Stalk/kill prey • Social dominance (against intruders) • Role of testosterone

25. Aggression • W/out influence of cortex – abnormal aggressive response (“sham rage”) • Inappropriately severe, non-directed • Aggressive displays What does this suggest? • Hypothalamus – aggressive behavior patterns • Cortex - directs at appropriate target

26. Stress

27. What is Stress? Stressor: experience or event that signals threat or harm, causes stress to an organism • Physiological or psychological • What were common stressors, evolutionarily? • What have we adapted to deal with?

28. What is Stress? • Societal demands • Noxious stimuli • Life changes • Lack of food • Physical activity • Predation • Etc…

29. Biological Mechanisms of Stress Hypothalamic-pituitary-adrenal axis • Hypothalamic control of anterior pituitary • Release of adrenocorticotropic hormone from pituitary • Activation of adrenal cortex • Release of glucocorticoids from adrenal cortex

30. Biological Mechanisms of Stress • Glucocorticoids - receptors on body cells • Metabolism, immune function • Measure of stress • Sympathetic activation - release of epinephrine/NE from adrenal medulla

31. Biological Mechanisms of Stress • Stress increases cytokines – hormone which influences immune system What might contribute to variability in response to stress amongst individuals? • Timing of exposure • Mood, reactive state (coping)

33. Stress and Health • Short term stress is adaptive – tend to stressor, mobilization of resources • Cytokines incr. immune function/combat infection • Long term stress is maladaptive • Immune function, inflammation

34. Stress and Immune Function • Immune cells respond to glucocorticoids • Susceptibility to disease? • Chronic stress – body tissue, mental health

35. Early Stress • Influence stress response across lifetime • Maternal stress during pregnancy • Oxytocin during childbirth - adaptive mechanisms • Hippocampus, neurogenesis • Glucocorticoid receptors

36. Behavioral & Psychiatric Disorders

37. Mental Health

38. What is a Psychiatric “Disorder”? Disruption in psychological function req. treatment, considered “abnormal” Many different behaviors: • Mood, threat perception, reward mechanisms, motivation, decision making, perception, sensorimotor function…

39. What is a Psychiatric “Disorder”? • Affective disorders, anxiety, perception of reality • Variation/distortion of normal behaviors • Extremes (normal distribution) • “Abnormal” is subjective • Interfere w/ “normal” function

40. History of Mental Illness • “Madness” - spiritual possession • Exorcism • Mental asylums for the “insane” • Inconsistent definitions of sanity • Sterilization, heavy medication

41. History of Mental Illness • Lobotomies, electroshock • Misdiagnosis of other conditions? • Toxins • Epilepsy • Developmental disorders

42. Modern Therapies Less controversial approaches… • Psychiatric, behavioral therapy • Psychopharmacological • Modern psychiatric hospitals

43. Modern Therapies • Improvement in diagnosis, classification of disorders • Symptom variability • Definitions can change • Diagnostic and Statistical Manual (DSM) 5

44. Modern Therapies • Self report • Same diagnosis, vastly different symptoms • Same symptoms, different diagnoses • Drugs – tool for understanding biological basis of disease • Outcome of drug therapy • Assumptions about drug pathway

45. Mood Disorders

46. Depression Major Depressive Disorder (MDD) - affect (mood) Distortion of normal response to loss, grief Reactive (specific event) or endogenous (no specific cause)

47. Depression • ~10% of population • Common symptoms: • Anhedonia • Sadness • Problems w/ daily functions • Lack of hygiene • Sleeping/eating disturbances

48. Depression • Diagnosis - 2 weeks of continuous symptoms (clinical depression) • Risk of suicide • Genetic and environmental factors • Ex. stress

49. Biology of Depression • Cell loss - prefrontal cortex, limbic structures • Physiological markers often unreliable • Inconsistency in diagnosis • Reduced 5-HT & NE receptor binding - likely due to reduced monoamine release • Treatment through monoamine agonists

50. Treatment for Depression • MAO inhibitor (reduce breakdown of 5-HT) • Monoamine reuptake inhibitor (SSRIs) • Tricyclics (reduce reuptake of 5-HT, NE)