Blogs / 80beats

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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By disrupting the memories of cocaine-addicted lab rats, researchers were able to keep the rats from seeking out a fix for up to a month. Researchers say the new study points the way towards possible drug therapies for human addicts, because memory is one of the main reasons why drug addicts who have gone sober suddenly find themselves jumping off the wagon. Environmental cues like visiting a place where you were high can make you remember the drug and weaken your resistance to taking it again [io9].

In the experiment, psychologists taught rats to associate a flashing light with the delivery of cocaine to their cages, making the light a “drug-associated memory.” Then researchers gave half the addicted rats a dose of a drug that interferes with proteins called NMDA-type glutamate receptors in rat brains. Previous work on addiction and post-traumatic stress has shown that these proteins—which are found on the surface of brain cells—are essential to memory formation. The receptors are also crucial to reconsolidating a memory—moving it from its storage area in long-term memory to brain regions that handle short-term memory [Scientific American].

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The unique patterns of lines and grooves in a person’s fingerprints have long been used for identification. But scientists now say they’ve developed a method to see what’s in your fingerprints, which could tell authorities not only who you are, but also what you’ve been doing.

Purdue University researchers used a technique called desorption electrospray ionization, or DESI, which involves spraying a solvent onto a fingerprinted surface and then analyzing the droplets that scatter off the print with a method called mass spectroscopy [Telegraph]. Spectroscopy has long been used in the lab to identify molecules by weight, but DESI can be used in the field. Study leader Graham Cooks says this method could identify trace elements of drugs like cocaine or marijuana, the leftovers from explosives like RDX, and potentially other chemicals.

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British researchers have found that giving nicotine to lab rats boosts their concentration and memory, and say that the findings could point the way towards pharmaceuticals that could treat the symptoms of Alzheimer’s and dementia. This benefit may be linked to the effect nicotine has on addicted smokers: The “boost” in concentration that smokers experience from cigarettes could help sufferers fight the mental decline associated with dementia, studies suggest [Telegraph].

Researchers are definitely not suggesting that elderly people take up smoking or start wearing nicotine patches in an attempt to ward off dementia, as the negative health effects would far outweigh any benefits. Lead researcher Professor Ian Stolerman said: “Nicotine, like many other drugs, has multiple effects, some of which are harmful, whereas others may be beneficial. It may be possible for medicinal chemists to devise compounds that provide some of the beneficial effects of nicotine while cutting out the toxic effects” [BBC News].

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Medical research is getting a little groovier. In a new report, scientists declared that the active ingredient in hallucinogenic “magic mushrooms” had beneficial effects on test subjects who took the substance under a doctor’s supervision. What’s more, the effects lingered; 14 months after the experiment, more than half the subjects reported still feeling an increase in well-being or life satisfaction, in terms of things like feeling more creative, self-confident, flexible and optimistic [AP].

The experiment was one of the few conducted in the four decades since the government cracked down on hallucinogens, banning most research and listing them as a dangerous drugs. Researchers say the study marks another shift in policy, which could yield research with dramatic insights. “These drugs are no longer being confined to rats in test tubes,” said David Nichols, a Purdue University pharmacologist who was not involved in the study. “What we’re looking at is a largely unexplored technology for brain science — it was discovered in the 1940s, set the psychiatry world ablaze in the 1950s, and was aborted by widespread recreational abuse, the reaction of the media and its confluence with the Vietnam war” [Wired News].

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When a “new and improved” sign catches your eye and your hand starts to move towards the product, an ancient part of the brain called the ventral striatum is at work. Researchers say a new study shows that primitive portion of the brain is activated when people try something unfamiliar, which suggests that the impulse to seek out new things has conveyed an advantage ever since the early stages of evolution.

To conduct the study, which was published in the journal Neuron, researchers took brain scans of volunteers who were playing a game. The test subjects were shown cards and had to pick the one they thought had a monetary reward attached; after a few repetitions, they knew which cards were most likely to win them some money. Then researchers started introducing new cards and watched the reaction. “What we found is that people preferentially go for the ones they’ve never seen before,” [lead researcher Bianca] Wittmann says. Rather than stick with the familiar — a picture for which they’ve already figured out the probability of getting money — they’d rather take their chance on a new picture [ABC News].

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The antismoking drug Chantix was considered a wonder drug for about 18 months; the drug helps people quit smoking by both reducing nicotine cravings and decreasing the pleasure derived from tobacco. Then the reports of scary side effects started leaking out. In November 2007 the Food and Drug Administration announced that the drug had caused suicides, psychosis, paranoia, and hallucinations. A wonder drug no longer, Chantix began to be perceived as a crazy pill.

Yet despite the growing concerns over the drug, a recent investigation has shown that the Veterans Affairs (VA) department continued to test Chantix on veterans who fought in Iraq or Afghanistan and who suffered from post-traumatic stress disorder (PTSD). In the aftermath of the revelations, Congress has called on the VA to immediately suspend the studies, and the agency is now sending letters to about 33,000 veterans who are taking the anti-smoking drug Chantix, warning them about possible side effects, including thoughts of suicide [AP].

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