mind and brain

I. Stress

a. The effects of short-term vs. long-term stressors

  • Short-term stressors (acute stress): Temporary, such as an exam or a public speaking event.

    • Effects: Heightened energy, increased heart rate, and faster breathing (adaptive).

  • Long-term stressors (chronic stress): Persistent, like caregiving for a sick family member or financial struggles.

    • Effects: Suppressed immune function, cardiovascular diseases, digestive problems, and mental health issues like anxiety or depression.

b. The HPA Axis and Negative Feedback

  • The HPA axis (Hypothalamic-Pituitary-Adrenal axis) is activated in stress:

    1. Hypothalamus releases CRH (corticotropin-releasing hormone).

    2. CRH signals the pituitary gland to release ACTH (adrenocorticotropic hormone).

    3. ACTH prompts the adrenal glands to release cortisol.

  • Negative Feedback: Elevated cortisol tells the hypothalamus and pituitary to reduce stress signals, returning the system to balance.

c. Physiological stress response

  1. Sympathetic Nervous System (SNS): Fight-or-flight response.

    • Increases heart rate, blood pressure, breathing rate.

    • Diverts blood to muscles and away from digestion.

  2. Cortisol:

    • Mobilizes energy (glucose/fats).

    • Suppresses non-essential functions (immune response, digestion, etc.).

d. General Adaptation Syndrome (Hans Selye)

  1. Alarm: Immediate response to stress (fight or flight).

  2. Resistance: Continued stress response, using stored energy.

  3. Exhaustion: Resources depleted, leading to health issues or burnout.

e. Types of stressors

  • Physical: Injury, environmental hazards.

  • Psychological: Public speaking, deadlines.

  • Acute: Short-lived, immediate (e.g., an exam).

  • Chronic: Persistent, ongoing (e.g., caregiving).

f. Ethics of studying stress

  1. Milgram Study: Participants believed they were inflicting harm, causing ethical concerns about psychological trauma.

  2. Zimbardo Prison Experiment: Highlighted the psychological harm caused by extreme stress situations and lack of ethical oversight.

II. Perception of Stress

a. Jay Weiss’s experiments

  • Key factors: Predictability and controllability reduce stress.

    • Rats with a predictable shock or control (lever to stop the shock) had lower stress.

b. Yoked Control

  • Definition: A control subject receives the same conditions but lacks control over the stressor.

    • Example: One rat presses a lever to stop shocks, while the yoked rat gets shocks without control.

c. Role of feedback

  • Feedback provides a sense of control, which lowers stress. Without it, individuals may feel helpless, increasing stress responses.

III. Emotions and Psychopathologies

a. Defining emotions

  • Emotions: Complex reactions involving subjective experience, physiological response, and behavioral expression.

  • Affect: Outward expression of emotion.

  • Mood: A prolonged emotional state.

b. Processing emotional experiences

  1. James-Lange: Emotions result from physiological reactions (e.g., trembling → fear).

  2. Cannon-Bard: Emotions and physiological responses occur simultaneously.

  3. Biopsychological View: Emotions, physiology, and environment interact dynamically.

c. Brain areas mediating emotions

  • Amygdala: Processes fear/emotional responses.

    • Low Road: Fast, unconscious response to threats.

    • High Road: Slower, deliberate processing.

  • Prefrontal Cortex: Regulates emotional responses.

  • Hippocampus: Links emotions to memories.

d. DSM (Diagnostic and Statistical Manual of Mental Disorders)

  • A standardized tool for diagnosing mental illnesses.

  • Ensures consistency and reliability in diagnoses.

e. Importance of reliable diagnostic tools

  • Reliability: Consistent diagnoses across clinicians.

  • Validity: Accurately identifies the disorder.

IV. Schizophrenia

a. Symptoms

  1. Positive Symptoms: Added behaviors (hallucinations, delusions).

  2. Negative Symptoms: Reduced functions (social withdrawal, flat affect).

b. Brain areas affected

  • Enlarged ventricles, reduced prefrontal activity (hypofrontality), and dysregulated dopamine pathways.

c. Treatment of schizophrenia

  1. Early drugs (e.g., Chlorpromazine): Dopamine D2 blockers, reducing positive symptoms but causing side effects.

  2. Recent drugs (e.g., Clozapine): Targets dopamine and serotonin receptors, improving both positive and negative symptoms.

d. Dopamine Theory

  • Overactive dopamine pathways cause positive symptoms. Supported by the effectiveness of dopamine-blocking drugs.

e. Role of Genes vs. Environment (Epigenetics)

  • Concordance rates: Identical twins show 50% concordance, indicating both genetic and environmental factors.

  • Epigenetics: Environment influences how genes are expressed.