Discuss Neural Mechanisms in the Control of Eating Behaviour
One major neural mechanism involved in the control of eating behaviour is the role of homeostasis. This is when the process by which the body maintains a constant internal environment. It is important to note, homeostasis is maintained via a negative feedback loop. In other words, each body has a set point. Therefore, the set point in obese people is more likely nearer to hunger, and thin people nearer to satiety. However, this is not always the case as some very overweight people do not eat as much as their weight suggests and some underweight people may eat quite a large amount of food.
Therefore, it is sensible to argue the fact that individual differences can influence set points. Such as, genetics, family, culture and society, or even medical conditions which promote weight gain or loss. A good example is oral corticosteroids, such as “deltasone”, carry a higher risk of weight gain, particularly with long-term use. Some people’s weight can even be affected by specific medical conditions, for instance, low or high thyroid. However, this is only 12% of people.
One other important neural mechanism involved in the control of eating behaviour is the dual theory of feeding behaviour. This theory suggests the hypothalamus has two areas that are involved in eating behaviour. Firstly, we have the lateral hypothalamus (LH) which controls hunger. Then we have the Ventro Medial hypothalamus (VMH) which controls satiety (feeling full). This theory gained much attention and thus research followed. A good example to use is the animal research which has been conducted, where rats have had their hypothalamus stimulated to see the effects of eating behaviour.
This research was done by Hetherington + Ranson (1942). Their study involved lesioning rats hypothalamuses. This is when areas of the brain (in this case hypothalamus) are cut away. The findings yielded some interesting results. For instance, it was revealed lesions to the VMH lead to hyperphagia (excessive eating) and weight gain. This study can be supported, however not directly. Anad and Brobeck found 9 years later, that lesions to the LH lead to under eating and weight loss. As a result, psychologists suggest if these areas have been effected (dysfunctional), eating disorders may occur such as obesity and anorexia.
This suggestion is so strongly supported that damage (such as a tumour) to the VMH (excessive eating) can actually lead to a type of obesity, hence the name “hypothalamic obesity”. Unfortunately, this form of weight gain is not responsive to diet and exercise and will actually gain weight regardless of their best efforts.
Regarding the original study, it is fair to say animal research is reliable in that it has a high level of control, this is because cause and effects can be clearly seen and analysed. However, at the end of the day humans are more complex than rats and there are social