Locusts are prompted to band together in enormous, destructive swarms by the same brain chemical that is linked to happiness in humans. A fascinating new study has found that locusts that are about to swarm experience a sudden surge of serotonin, the same neurotransmitter that’s targeted by antidepressant drugs. “Here we have a solitary and lonely creature, the desert locust. But just give them a little serotonin, and they go and join a gang,” observed Malcolm Burrows [AP], one of the study’s authors.

Researchers say the findings may lead to methods to block the formation of locust swarms. These infestations, which can cover hundreds of square miles and involve billions of vegetation-munching insects, can devastate agriculture and cost tens of millions of dollars to control [The New York Times].

Because locusts usually avoid each other, it’s only dire circumstances that bring them together in buzzing hordes. For instance, unpredictable desert rains cause vegetation blooms, which in turn makes locust populations skyrocket. But as the rains abate and fertile land shrivels up, locusts crowd together in the remaining green patches. Eventually, the swarm trigger goes off and the locusts take to the skies—”a strategy of desperation driven by hunger,” [National Geographic News], says coauthor Stephen Rogers. When they make that behavior shift they also change appearance dramatically, going from light green to dark brown.

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Gay young adults who were rejected by their families when they came out as teenagers are much more likely to attempt suicide, have unprotected sex, and have problems with drug use and depression, according to a new study. The findings are based on surveys of 224 gay, lesbian, bisexual and transgender adults in California who ranged in age from 21 to 25. Gay Latinos were most likely to experience a poor reception from their parents, and had the highest rates of risk factors for HIV and mental health problems, according to the research [Scientific American].

The findings, published in the journal Pediatrics [subscription required], don’t prove that a family’s negative reaction to a child’s sexuality directly causes problems later in life. But it’s clear that “there’s a connection between how families treat gay and lesbian children and their mental and physical health” [HealthDay News] said social worker Caitlin Ryan, the study’s lead author. She found that teenagers who were rejected by their families were eight times as likely to attempt suicide, six times as likely to report serious depression, and three times as likely to have unprotected sex and use drugs.

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Happiness is catching and spreads like the flu, according to a study that followed a whole community of people for 20 years. The effect of one happy person could ripple through three degrees of separation, researchers report. “It is sometimes said that you can’t be happier than your least happy child. It is truly amazing to discover that when you replace the word ‘child’ with ‘best friend’s neighbor’s uncle,’ the sentence is still true,” [Boston Globe] said psychologist Daniel Gilbert, who was not involved in the study. The researchers liken the pattern of happiness transmission to the spread of a virus: those with the most number of happy contacts are the mostly likely to catch the happy bug.

The study, published in the British Medical Journal, followed more than 4,700 people living in Framingham, Massachusetts from 1983 to 2003. The participants answered periodic questionnaires about their emotional well-being and listed the names of relatives, friends, and co-workers, many of whom were also participating in the study. Researchers found that happiness wasn’t scattered evenly throughout the population but instead seemed to spread through social networks. “Happiness is like a stampede,” said [co-author] Nicholas Christakis… “Whether you’re happy depends not just on your own actions and behaviors and thoughts, but on those of people you don’t even know” [AP].

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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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A new study of the prairie vole, a rodent species famed for its monogamous ways, has shown that the vole’s brain chemistry changes when its mate is taken away, and that it loses some of its vim and vigor. Researchers compared the behavior of males who were separated from either their mates or their siblings, and found that those voles who had lost their loyal mates were passive and unresponsive–maybe even depressed.

Prairie voles are one of the few mammals that are generally monogamous; the mates form life-long bonds and rear their pups together. In the new study, researchers subjected all the male voles to stress tests, like dunking them in basins of water and holding them suspended by their tails, and found that the voles whose mates had been spirited away put up less struggle. In the water, for example, they floated listlessly instead of paddling for their lives. These voles “basically were passive — they gave up,” [study coauthor Larry] Young said. “I would be hesitant to say that these animals were depressed, but their behavior is reminiscent of what you would see in a depressed person” [HealthDay News].

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The little blue pills that have given so many men a sexual boost may be of some use to women as well. A small study looked at women whose sex lives had suffered as a side effect of taking antidepressants, and found that Viagra increased their sexual sensation and orgasms.

However, the pills didn’t boost the women’s sex drive, leading some experts to question whether the medication could help most women. “Viagra is not a desire drug. It dilates the blood vessels, allowing intercourse to occur,” said Rutgers University psychology professor Barry R. Komisaruk, an expert on sexual dysfunction. [Sexual health expert Leonard] Derogatis agreed: “The most prevalent female sexual dysfunction is not arousal but desire. Viagra doesn’t have a direct effect on that,” he said [Baltimore Sun].

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Researchers have the best evidence yet that the brain chemical serotonin plays a role in sudden infant death sydrome (SIDS).

In a new study, researchers genetically engineered mice to have low levels of serotonin at birth, and found that more than half of the mice abruptly died before they were 3 months old. More intriguing, they had erratic episodes where their heart rate would drop and, five to 10 minutes later, so would their body temperature, [study author Cornelius] Gross reported. Sometimes they died in the midst of what Gross calls those crises, other times afterward [AP].

Serotonin is most commonly known as a mood regulator involved in depression, but it also helps control some of the body’s most basic functions, including breathing, heart rate, and body temperature. The mouse study supports earlier data gathered from the autopsied brain tissue of SIDS babies, which showed alterations in brainstem nerve cells that communicate using serotonin.

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Researchers have made a map of the human brain that shows a dense network of connections at the top of the cerebral cortex, suggesting that electrical signals travel through this hub on their way to more specialized regions. “This is just about the coolest paper I’ve seen in a long time, and forward-looking in terms of where the science is going,” said Dr. Marcus E. Raichle, a professor of neurology and radiology… who was not involved in the research. He added, “They’ve found in the brain what looks like a hub map of the airline system for the United States” [The New York Times].

An international team of researchers used a technique called diffusion spectrum imaging to map the connections between different parts of the brain. The technique traces the path of water moving along axons, long fibers that extend from a neuron’s main body and carry electrical signals [Science News]. They found the most connections at the top of the cortex along the crack that separates the brain’s two hemispheres. According to researchers, that area is not only a relay station, it’s also the area that’s most active when the brain is in “default mode,” the activation state present when the brain is not engaged in any specific cognitive task [The Scientist].

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Here’s one easy way to help avoid conflict and strife in your interactions with others: When you eat your three square meals a day, don’t skimp on the meats and cheeses.

Those foods contain high levels of the amino acid tryptophan, which the body needs to produce the neurotransmitter serotonin, a chemical in the brain that plays a role in regulating mood, aggression and social behavior. In a new study, test subjects with high serotonin levels responded less aggressively while making emotionally charged financial decisions in a test known as the ultimatum game.

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