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Neural Mechanisms in Eating and Satiation Essay Plan
1. Describe in detail the lateral hypothalamus. Outline studies about Neuropeptide Y, by
Wickens; when injected into the hypothalamus of rats, NPY causes them to immediately
begin feeding, even when satiated, and Stanley; repeated injections of NPY into the
hypothalamus of rats produces obesity in just a few days.
2. Outline briefly in a couple of sentences the role of the ventromedial hypothalamus.
3. Critical Point 1: There are a couple of problems with the explanation about what the lateral
hypothalamus does. Sakurai in 1998 discovered that it is not only the hypothalamus that
controls eating behaviour, it is also neural circuits that run throughout the brain and so the
hypothalamus is not the brain's "eating centre". Therefore, this evidence disregards the
explanation that it is only the hypothalamus that controls eating.
4. Critical Point 2: This theory is unreliable. Marie in 2005 genetically manipulated mice so that
they didn't make NPY and found no significant decrease in their feeding behaviour. This
disproves the explanation about the neurotransmitter NPY which is activated by the LH and
so disproves this too. Also, there are serious ethical issues to consider about conducting this
type of research as it is not ethical to cut open mice, if it was a human it would not be allowed
unless they were dead.
5. Critical Point 3: Generalisability- many of the experiments have been done on small
creatures, in particular rats, therefore, we cannot say that humans will react in the same way
if the same experiments were performed on them.