The picture shows where we like seeing milkshakes! There are different regions in the brain that give us positive emotions when we see or smell foods we like as opposed to actually eating foods we like. Emotion is partly mediated by dopamine signaling in the amygdala and striatum of the brain. The striatum has ventral (front) and dorsal (back) parts. The ventral striatum contains the nucleus accumbens and olfactory tubercle and responds to food CUES (seeing or smelling food) but NOT to food RECEIPT (taste and consumption) unless the food was unexpected. On the other hand, the dorsal striatum contains the caudate nucleus ("c" shaped structure) and putamen and responds to food receipt, with a decreasing response as we get full. So we like chocolate less when we are full [1]. So in the striatum, the front part makes us happy when we see or smell food, and the back part makes us happy when we taste and eat it. Genetic mutations leading to reduced dopamine signaling strength when we eat foods would be expected to make us eat more foods to compensate. Using MRI, it has been shown that reduced dopamine signaling in response to consuming a milkshake (compared to water) was correlated to higher body fat levels as well as body fat gains over 1 year in college-aged women [2]. This can be partly due to genetics, and it is known that dopamine signal-strength is down-regulated by excesive intake of palatable foods, a pattern also seen with chronic substance abuse i.e. addiction.
1. Changes in brain activity related to eating chocolate: from pleasure to aversion", Small DM et al., Brain 124 (1720) 1720
2. "Relation between obesity and blunted striatal response to food is moderated by the TaqIA A1 allele", Stice E et al., Science 322 (2008) 449
So the more you eat something that you like, the more of it that you need to eat in order to become satisfied... this rings a bell!
BTW, I just had an epiphany. Instead of getting their hearts broken trying to search the PubMed Web site directly, they can use scholar.google.com instead. If only I had this when I was taking your class!
For example, compare the results between the sites with the following search terms: protein intake nitrogen balance. PubMed returns fairly non-sensical results, IMO.
+1
Posted by: flash games collection | July 10, 2012 at 03:06 PM
So the more you eat something that you like, the more of it that you need to eat in order to become satisfied... this rings a bell!
BTW, I just had an epiphany. Instead of getting their hearts broken trying to search the PubMed Web site directly, they can use scholar.google.com instead. If only I had this when I was taking your class!
For example, compare the results between the sites with the following search terms: "protein intake nitrogen balance." PubMed returns fairly non-sensical results, IMO.
Posted by: Darwin | October 03, 2009 at 09:38 PM