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🎯 Main Points

Chapter 39

PSYP610 - Neurological Bases of Behavior

🔑 Key Definitions

Glucostatic Theory: Mayer's theory that hunger is triggered by decreased blood glucose availability
CCK (Cholecystokinin): Gut hormone released during eating that signals satiety to brain
LH (Lateral Hypothalamus): "Feeding center"; stimulation causes eating, lesion causes starvation
VMH (Ventromedial Hypothalamus): "Satiety center"; stimulation stops eating, lesion causes obesity

👤 Important Figures

  • Walter Cannon & A.L. Washburn - Studied stomach contractions; balloon swallowing experiment demonstrated hunger correlates with stomach contractions
  • Jean Mayer - Developed glucostatic theory; proposed glucose utilization signals hunger/satiety

🧠 Hunger Signals

  • Oral Factors: Taste, smell, texture of food; immediate but temporary influence
  • Stomach Contractions: Cannon & Washburn showed correlation with hunger, but not necessary (people without stomachs still feel hunger)
  • CCK (Satiety Signal): Released from intestines during eating; signals "stop eating"
  • Metabolic Factors: Blood glucose, insulin, leptin levels influence hunger

📊 Hypothalamic Control

  • Lateral Hypothalamus (LH): "Feeding center"; damage causes aphagia (refusal to eat), eventual starvation
  • Ventromedial Hypothalamus (VMH): "Satiety center"; damage causes hyperphagia (overeating) and obesity
  • Dual-Center Model: LH promotes eating, VMH inhibits eating; balance controls food intake

📊 Glucostatic Theory

  • Mayer's Proposal: Hunger triggered when glucose UTILIZATION decreases (not just glucose levels)
  • Glucose Sensors: Hypothalamus and liver monitor glucose availability
  • Insulin Role: Allows glucose into cells; low insulin = cells can't use glucose = hunger

💡 Exam Tips

  • Cannon & Washburn = stomach contraction experiments
  • LH = eating ON (lateral = "go eat"), VMH = eating OFF (ventromedial = "stop")
  • CCK = satiety hormone from gut
  • Glucostatic theory: it's about glucose UTILIZATION, not just levels
  • Dual-center model: LH vs VMH balance controls hunger
  • Remember: LH lesion = won't eat (aphagia), VMH lesion = overeat (hyperphagia)