Psychobiology Exam 4 Notes

Schizophrenia

• Onset: Schizophrenia typically begins in adolescence or early adulthood.
• Hallucinations: Often take the form of voices.
• Brain Imaging: Structural brain imaging studies reveal that findings often include:
  • Enlarged ventricles
  • Reduced gray matter in the cortex
  • Abnormalities in brain regions involved in cognitive and emotional processing.
• Prevalence: About 1% of the adult population is diagnosed with schizophrenia.

Affective Disorders

• Concordance Rates: Rates are highest for bipolar disorders and monozygotic twins, indicating a strong genetic component.
• Monoamine Theory: Based on the observation that most effective treatments for depression increase the levels of monoamines in the brain.
• MAO Inhibitors: Not commonly used anymore because they block MAO's ability to break down tyramine, leading to potentially dangerous dietary restrictions.

Anxiety Disorders

• Prevalence: Anxiety disorders are the most prevalent psychiatric disorders.
• Obsessive-Compulsive Disorder: Characterized by recurring uncontrollable anxiety-producing thoughts and impulses.
• Benzodiazepines: Medications that bind to GABA A receptors, enhancing inhibitory neurotransmission, commonly used for anxiety treatment.

Emotion Theories

• James-Lange Theory: Proposes the experience of emotion is based on the perception of bodily reactions. E.g., one feels fear because their heart races.
• Cannon-Bard Theory: Asserts that the feeling of emotion and the physiological expression of emotion occur simultaneously and independently.
• Papez Circuit: Attributes emotion to the activities in the limbic system, involving structures such as the hippocampus and amygdala.

Aggression and Behavior

• Kluver-Bucy Syndrome: Results from bilateral damage to the amygdala, leading to altered emotional responses.
• Testosterone and Aggression: Evidence is inconsistent about testosterone's effect on human aggressive behavior; factors like social context also play a role.
• Antianxiety Drugs: In studies, they have been shown to increase the efficiency of predatory behaviors in animals, such as increased success in hunting.

Stress Measurement

• Physiological Measure: The most commonly employed measure of stress is the level of circulating glucocorticoids, particularly cortisol, which is released in response to stressors.