Biopsychology of Emotion, Stress, and Health Notes

Chapter Overview

  • Biopsychology of Emotion
    • Learning Objectives:
    • LO 17.1: Major events in the history of emotion research.
    • LO 17.3: Research on facial expressions of emotions.
  • Stress and Health
    • Learning Objectives:
    • LO 17.14: Components of the stress response.
    • LO 17.17: Definition and components of psychoneuroimmunology.

Key Concepts in Emotion Research

Phineas Gage

  • Incident (1848): Tamping iron through skull led to significant personality change due to damage to medial prefrontal lobes.
  • Outcome: Provided insight into the relationship between brain regions and emotions.

Darwin’s Theory of Emotional Expression

  • Evolution: Emotional expressions evolve from behaviors indicating future actions.
    • Principle of Antithesis: Opposite emotional signals often communicated through opposing physical gestures.
      • Example in dogs:
      • Aggressive: Ears forward, back arched, hair up, tail up.
      • Submissive: Ears back, back down, hair down, tail down.
  • Threat Displays: Function to intimidate without direct costs or risks of fighting.

Theories of Emotion

James-Lange Theory
  • Emotion arises from autonomic/skeletal responses triggered by stimuli.
  • Autonomic/skeletal responses are necessary for experiencing emotion.
Cannon-Bard Theory
  • Emotion and autonomic/skeletal responses occur simultaneously upon stimulus presentation.
  • Independent autonomic and emotional responses.

Facial Expressions of Emotion

  • Universality: Six primary emotions recognized globally: surprise, anger, disgust, fear, sadness, happiness.
  • Microexpressions: Brief, involuntary facial expressions that reveal true emotions that may differ from the expressed feelings.
    • Duchenne Smile: Distinguishes between genuine and fake smiles through differing muscle involvement.

Understanding Stress

Stress Response

  • Definition: Physiological reactions to perceived threats or harm.
  • Triggers:
    • Hormonal: Activation of anterior-pituitary adrenal-cortex system, releasing glucocorticoids.
    • Neurotransmitters: Activation of sympatho-adrenal system, releasing epinephrine and norepinephrine.
    • Cytokines: Induce inflammation and fever.
  • Individual Variability: Response influenced by the nature of the stressor, individual perceptions, and coping strategies (McEwen, 1994).

Stress Pathways

  1. Acute Stress:
    • Hypothalamus → Sympathetic nervous system → Adrenal medulla → Immediate physiological responses (e.g., increased heart rate).
  2. Prolonged Stress:
    • Hypothalamus → Pituitary gland → Release of ACTH → Adrenal cortex → Long-term responses (e.g., energy mobilization, reduced immune response).

Psychoneuroimmunology

  • Definition: Study of interactions between psychological factors, the nervous system, and immune function.
  • Effects of Stress on Immune Function:
    • Acute stressors (eustress) can enhance immune response.
    • Chronic stressors (distress) can impair immune function.
    • Mechanisms:
      • Lymphocytes (white blood cells) have receptors for stress hormones which can influence their activity.
      • Behavior modifications due to stress can also affect susceptibility to infections.