What’s the News: The bacterium that causes ulcers and some stomach cancers, Helicobacter pylori, could at least contribute to Parkinson’s disease, according to a new study in mice presented at a microbiology conference yesterday. Mice infected with H. pylori have shown Parkinson’s-like symptoms, building on earlier work that has suggested a link between the bacteria and Parkonson’s disease.

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What’s the News: Researchers have found that whether people stick with advice they were given, even when their own experience contradicts it, is linked to their genes, according to a new study published online in the Journal of Neuroscience. These findings suggest a possible genetic component of confirmation bias, the tendency to focus on new information that agrees with what you already know, and ignore information that contradicts your views.

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Those delicious chills you get as your favorite piece of music reaches its climax? They’re the result of a glorious spike of dopamine in your brain–that’s the same neurotransmitter that’s involved in reward, motivation, and addiction.

In a nifty series of experiments published in Nature Neuroscience, researchers determined that music provokes floods of dopamine in music lovers. Study coauthor Valorie Salimpoor notes that dopamine has long been known to play a role in more physical activities like taking drugs and having sex, but this research highlights its role in other aspects of our lives.

“It is amazing that we can release dopamine in anticipation of something abstract, complex and not concrete,” Salimpoor said. “This is the first study to show that dopamine can be released in response to an aesthetic stimulus.” [Discovery News]

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Do you often feel the need for a sweet sugar rush or a moment of bacon-induced bliss? A new study offers evidence that that surge of pleasure is similar to a heroin high, and that eating junk food regularly can significantly change the brain’s chemical make-up, creating junk food addicts who are driven to overeat.

Lead researcher Paul Kenny says it had previously been unclear whether extreme overeating was initiated by a chemical irregularity in the brain or if the behavior itself was changing the brain’s biochemical makeup. The new research by Kenny and his colleague Paul Johnson, a graduate student, shows that both conditions are possible [Scientific American].

For the study, published online in Nature Neuroscience, Kenny and colleagues headed to the grocery store. “We basically bought all of the stuff that people really like — Ding-Dongs, cheesecake, bacon, sausage, the stuff that you enjoy, but you really shouldn’t eat too often,” he said [Reuters]. One set of lab rats was allowed unfettered access to these high-calorie foods, while another rat group was allowed just one hour of access to the junk food per day. Both sets of rats also had the option of eating standard healthy lab rat fare. Finally, a control group of rats were kept on a healthy diet.

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To a gambler’s brain, a near miss provides almost the same high as a win, according to a new study that helps explain the allure of slot machines and the difficulty that some gamblers have in walking away. “The near-miss is quite a paradoxical event,” [researcher Luke] Clark says. Gamblers who almost win put “their head down in their hands — they can’t believe it. And then the next thing they do is place another bet” [Science News].

In the small study, published in Neuron [subscription required], researchers had 15 volunteers play a slot machine while their brain activity was recorded with fMRI scans. When the researchers compared the scans, they found that near misses drew more blood to reward regions such as the insula and the ventral striatum than full misses did [ScienceNOW Daily News]. These areas are also activated by rewards like chocolate and cocaine; when the near misses partially activated the so-called reward pathway, it released pleasant doses of the brain chemical dopamine.

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The global economic crisis has everybody looking for scapegoats–and now we may have a couple, in the form of a pair of genes that influence people’s desire to take financial risks. The two genes regulate dopamine, the brain chemical associated with reward and risk-taking, and serotonin, the chemical linked to mood and anxiety. In a new study, researchers found that people with the “high-risk” version of the dopamine gene tended to invest in risky but potentially lucrative propositions, while those with the “high anxiety” version of serotonin managed their money more carefully [Reuters].

While an experiment showed a clear correlation between the genes and risk-taking behavior, study coauthor Camelia Kuhnen says the results don’t suggest that all bankers should get their DNA tested. “I wouldn’t want to oversell this as a screening device to find good traders…. Even if I have a gene that predisposes me to taking a lot of financial risk, I could go through a stock market crash that will make me less risk-taking” [Scientific American], says Kuhnen.

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In a counterintuitive new study, researchers have found that obese women get less pleasure from drinking a chocolate milkshake than average-weight women, and suggest that obese women are therefore more likely to overeat in an attempt to get that high. Researchers used a fMRI brain scanner to record women’s levels of the pleasure-providing brain chemical dopamine while they were sipping milkshakes, and found that obese women had a muted pleasure response.

They also studied a dopamine-regulating gene variant that has previously been linked to obesity, and showed that women with this variant had the lowest dopamine levels and were also very likely to gain weight over the ensuing year. Dopamine expert Nora Volkow says this furthers the research on the genetic component of obesity: “It takes the gene associated with greater vulnerability for obesity and asks the question why. What is it doing to the way the brain is functioning that would make a person more vulnerable to compulsively eat food and become obese?” [AP]

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