Neural Mechanisms Flashcards
How is the hypothalamus involved in eating and satiation?
ventromedial = satiation, lateral = hunger
What is the glucostat theory? Why is this theory incorrect?
blood glucose is the main signal to hypothalamus but levels don’t change enough to show hunger/satiety so theory is false
Who conducted research on animals into the role of the ventromedial hypothalamus?
Hetherington and Ranson 1942: lesions to the VMH in rats = increased feeding and body weight
Who conducted research on animals into the role of the lateral hypothalamus?
Anand and Brobeck 1951: lesion to LH = loss of feeding in rats (aphagia)
What IDA point can be made about research into the role of the hypothalamus?
biological vs psychological hunger (rats aren’t the same as humans)
What is the role of ghrelin in eating and satiation?
hormone secreted from empty stomach, acts on hypothalamus
Who conducted research into the role of ghrelin?
Cummings 2004: blood ghrelin levels between meals, dropped after eating and rose over time (6 Pps, correlational but support previous findings, medically accurate, isolation from time cues)
What is the role of leptin in eating and satiation?
hormone released from fat tissue (adipocytes), acting on hypothalamus in long term, controls fat and weight norm, stimulates satiety when there is more fat tissue
Who conducted research into the role of leptin?
Carlson 2007: genetically obese mice don’t produce leptin (fixed by injection)
What is the relevance of leptin in obese people?
brain mechanisms controlling feeding behaviour are insensitive to leptin, leptin levels are rarely low
What is the practical application of leptin research?
Reduce obesity in pets as animal research cant apply to humans, injection wouldn’t work as humans insensitive to leptin once obese
What is CCK?
cholecystokinin: hormone released from duodenum (short section of intestines) when food is detected, satiety signal sent to inhibit feeding
Who conducted research into the role of CCK?
Smith, Gibbs and Kulkosky 1982: CCK injections in animals and humans reduces meal size, animals that genetically don’t have CCK become obese
What is the practical application of research into CCK?
new diet pills/injections containing CCK for obese patients who are unable to lose weight by diet/exercise
