Neural Mechanisms

Question 1

What are the two eating systems and how do they work

Answer 1

Low glucose levels activates the Lateral hypothalamus
Increased glucose levels activated the Ventromedial hypothalamus

Damage to the lateral hypothalamus can lead to a decreased appetite and damage to the Ventromedial hypothalamus can lead to overeating and not feeling full. This suggests that the LH initiates eating behaviour and the VMH stops eating behaviour

Question 2

The lateral hypothalamus

Answer 2

Scientists first discovered that damage to the lateral hypothalamus in rats caused aphagia.

Question 3

Support for lateral hypothalamus

Answer 3

Stanley et al. A neurotransmitter called neuropeptide has also been found to be really important to activate eating behaviour. When injected with NPY rats started eating even when satiated. After numerous injections the rat became obese. This suggests that perhaps people continue to eat so much because the brain is producing excessive amounts of NPY

Question 4

Criticism of lateral hypothalamus

Answer 4

Recent research in California has found that NPY is also produced by abdominal fats and so the vicious cycle begins.
Yang et al believe that people could be treated with drugs to control their production of NPY and as a result they would be able to regulate their eating

Question 5

Conclusion of lateral hypothalamus

Answer 5

Although the LH does play an important role in eating behaviour, recent research has indicated that neural circuits which control eating run through the brain so the LH may not be as important as it was once thought

Question 6

The Ventromedial hypothalamus

Answer 6

Damage to the VMH can also cause overeating.
Gold noted that damage to the Paraventricular nucleus alone, which is another area of the hypothalamus, can cause overeating, as it is responsible for most of our cravings

Question 7

Support for Ventromedial hypothalamus

Answer 7

Early research found that damage to the Ventromedial hypothalamus resulted in overeating and obesity in certain species. Gold found that damage to the VMH only produced overeating when other areas like the Paraventricular nucleus were also damaged

Question 8

Conclusion for Ventromedial hypothalamus

Answer 8

Damage to the VMH also causes damage to other nerves and brain tissue so specific causes are not 100% accurate

Question 9

Evaluation of neural mechanisms

Answer 9

• reductionist
• deterministic
• free will