Discuss the Role of Neural Mechanisms in Controlling Eating and Satiation

Essay Question

Discuss the role of neural mechanisms in controlling eating and satiation (9 + 16)

A01

• Dual Centre Model of Feeding
• All humans and mammals are homeostatic - run our bodies on constant state of balance
• "Feeding" Centre in the brain activated when we are hungry
• "Satiety" Centre in the brain activated when we are full
• Hypothalamus in the brain regulates eating behaviour
• Blood glucose levels drop or ghrelin levels increase - Lateral Hypothalamus is activated - feel hungry and eat
• Blood glucose levels increase or ghrelin levels decrease - Ventromedial Hypothalamus is activated - feel full and stop eating 

A02

• Support - Heatherington and Ranson 1942
• Lesions to the Ventromedial Hypothalamus caused rats to become obese
• Lesions destroyed satiety centre - led to uncontrolled eating and an inibility to feel full
• Ventromedial Hypathalamus normally activated when animal is full or satiated
• Ventromedial Hypathalamus' function is to stop feeding

• Support - Anand and Brobeck 1951
• Lesioning to the Lateral Hypothalamus led to loss of feeding in rats - aphagia
• Lesions damaged feeding centre - no longer activated when blood glucose levels decreased
• Lateral Hypothalamus' normal function is to stimulate feeding and feelings of hunger

However

• Extrapolation
• Means - Research conducted on rats to explain human behaviour but humans are different to rats
• Example - Humans are more complex and might react in a different way to having their hypothalamus lesioned in this way
• Problem because - Findings cannot be generalised to human eating behaviour

However

• Reductionism - Ignores research into the influence of biological rhythms
• Means - Neurological mechanisms are more complex than just the dual centre model
• Example - Rats are more active…