Neural Mechanisms in Eating Behaviour - Plan

Discuss neural mechanisms involves in the control of eating behaviour (8+16) - plan

• AO1 Homeostasis and the internal working environment - the time gap between eating and satiety.
• AO1 Reduction of glucose causes the message to lateral hypothalamus. 
• AO1 Seen as ‘eating centre’ and creates feeling of hunger.
• AO2 Anand and Brobeck 1951 - A lesion in the lateral hypothalamus led to a loss of feeding behaviour in rats known as aphagia. Electrical stimulation produced feeding 
• AO3 Use of rats and lab setting - high internal validity but struggling to generalise due to differences in rats and humans, despite similar brain structures. 

• AO1 Ghrelin released by lateral hypothalamus and human feels hungry and then seeks out and consumes food. 
• AO1 triggers response from ventromedial hypothalamus which sends message to stop eating 
• AO2 Hetherington and Ranson 1942 - Lesions in the VMH caused rats to overeat and become obese. 
• AO2 Damage to VMH has caused hyperphagia and obesity in many species, including humans. (although usually damage much be present in the paraventricular nucleus)
• AO3 much much applicable to humans sue to some studies being tested on them. Unecthical treatment of rats. 
• AO1 the feeling of satiety prevents overeating.

• AO1 Neuropeptide Y is sometimes seen as the neurotransmitter which could be responsible to overeating. 
• AO2 This could be seen as the (real-world-application) reason why people become obese - due to an overproduction of neuropeptide Y. 
• AO2 When rats were injected with neuropeptide Y, they became obese due to overeating. 
• AO2 however, Marie et al 2005 genetically modified rats without NPY and eating behaviour didn't change. 
• AO3 conflicting studies make results low in validity and hard to generalise. 

• AO1 also looked at is the role of the stomach and its contractions when hungry. 
• AO2 Canon and Washburn put balloon in stomach and witnessed more contractions of balloon when hungry. 

• AO3 IDAs - Use of animals - rats - similar brain structure, god control, not directly relatable with behaviour/biology, doesn't have implications like social pressures, immoral due to unethical treatment, speciesism, more ethical than using humans, cost-benefit analysis
• AO3 IDAs - Biological Approach - biology dictates choices, genes are the main contributing factor, no explanation of social pressures, doesn't explain association, links to ….
• AO3 IDAs - Determinism vs free will - biological impact of genes leaves no control, things like NPY can’t be altered, role of stomach is central to human biology and can’t be changed though this is debatable - gastric bands (real life applications?)