Sleepy Bees Lose Their Rhythm

Sleep deprived and having trouble communicating? You aren’t alone. Drowsy honey bees (Apis mellifera) are incoherent, too, researchers report online today in the Proceedings of the National Academy of Sciences. Every morning, the bees set off on their daily foraging trips and return to the nest to perform a waggle dance. The angle of the bee’s body relative to the sun indicates the direction its comrades must fly in to find the good flowers, and the duration of its dance tells how far away they are. Sleep-deprived bees—kept up all night by researchers agitating them—made more errors when communicating the direction of the flower than did well-rested bees; at least until they had caught up on their sleep. Experiments to demonstrate whether bee insomnia is bad for the colony’s survival are underway; until the results are in, worker bees are advised to be tucked up in a hive, with a hot cup of nectar by 9 p.m.

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Odor Exposure in the Womb Primes the Palate

Moms, want your children to eat their greens? Then you have to eat them, too, at least while you’re pregnant. Researchers have found that offspring of mouse mothers fed a diet enhanced with cherry and mint flavors during pregnancy continued to prefer these flavors into adulthood, while mice from mothers fed on a bland diet had no food preference. The rodents with a penchant for mint-cherry food developed larger glomeruli, the region of the brain responsible for processing odor—the first evidence that exposure to odors in the womb alters the way the brain develops. From the fetus’ point of view, this is a good evolutionary strategy; eat the foods that your mother ate because they are probably safe. It is likely that all mammals, including humans, develop their sense of taste in this same way, the researchers report online today in the Proceedings of the Royal Society B, so expectant moms, be careful the next time you have a hankering for anchovies with chocolate sauce.

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Rethinking Brain Evolution in Insects

As surprising at it may seem, wasps, bees, and even ants have relatively large and complex brains. That allows these “social insects” to keep track of the intricate relationships between the thousands of individuals in their colony—or so researchers thought. A new study indicates that these insects didn’t grow big brains to cope with social living; they evolved them millions of years earlier when they were solitary parasites.

The link between brain size and social living was first noted in 1850, when scientists identified mushroom bodies in the insect brain. Aptly named because they’re shaped like mushrooms, the structures contain thousands of neurons responsible for processing and remembering smells and sights. Social insects tend to have larger mushroom bodies than solitary ones, leading researchers to believe that the transition from solitary to social living increased the size of these brain regions.

But Sarah Farris has found a different explanation. Instead of comparing social insects with solitary ones, Farris, a neurobiologist at West Virginia University in Morgantown, looked into the past. To get a sense of how the wasp brain evolved over time, she and taxonomist Susanne Schulmeister of the American Museum of Natural History in New York City compared the mushroom bodies of parasitic wasps with those of nonparasitic wasps, which represent the very oldest form of wasp. The parasitic wasps had consistently larger and more elaborate mushroom bodies than the nonparasites, the duo reports online today in the Proceedings of the Royal Society B. In particular, the caps, called calyces, of the parasitic mushroom bodies were twice the size of nonparasites.

Farris points out that parasitism evolved 90 million years before social insects appear, and so “insects had big mushroom bodies for quite a while before sociality arose.” This is the first evidence that parasitism, and not sociality, was the driver of insect mushroom body complexity, she says. That may be because well-developed mushroom bodies help parasitic wasps better locate the nests of the larvae they lay their eggs in.

Francis Ratnieks, an evolutionary biologist at the University of Sussex in the United Kingdom agrees with the study’s findings, but he thinks the researchers need to also look at the brains of social insects. It would be useful, for example, to compare the brains of social worker bees, which process vast quantities of visual information as they fly from flower to flower, with those of parasitic wasps. If bees have even larger mushroom bodies than parasitic wasps, he says, this would suggest that social insects have further improved on the brains that they inherited from their ancestors.

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Brain Zaps Improve Math

Need to improve your math skills or do your taxes faster? Try zapping your brain with electricity. Researchers have shown that administering a small electrical charge to the brain may enhance a person’s ability to process numbers for up to 6 months. The team says the approach, which it claims is harmless, could one day restore numerical skills in people suffering from degenerative diseases or stroke, and it may even improve the math abilities of the general population.

The brain’s math center appears to be the right side of the parietal lobe, a region that sits beneath the crown of the head. People with injuries to this region have difficulty counting, and it’s unusually active in young children learning their 1, 2, 3s. Those findings made Roi Cohen Kadosh, a cognitive neuroscientist at the University of Oxford in the United Kingdom, wonder if stimulating this part of the brain could improve a person’s ability to manipulate numbers.

Cohen Kadosh and colleagues recruited 15 university students and trained them to learn the value of nine made-up symbols, including shapes that looked like triangles and staples (see picture). To replicate what children go through when they first learn numbers, the researchers presented the volunteers with two symbols at a time and asked them which one had a higher value. At first, the volunteers had to guess, because they had never seen the symbols before. But as the training progressed, those volunteers who remembered their correct guesses began to learn the relative value of all nine symbols.

During 6 days of training, the researchers passed electrical currents into the volunteers’ brains. Using a technique called transcranial direct current stimulation (TDCS), the team attached electrodes to the scalps of the volunteers—over the right side of the parietal lobe—and applied a weak electrical current. Each day, five volunteers received a positive current for 20 minutes; five volunteers received a negative current for 20 minutes; and five volunteers received a positive current for 30 seconds. The volunteers usually report just a “tingling sensation” around the electrodes on the scalp, says Cohen Kadosh, who says that he tried out the procedure on himself before subjecting anyone else to it.

Each training day ended with a type of test known as a numerical Stroop task. In the classic version of the test, volunteers are shown, say, the word “blue” written in red ink and asked to state the color of the ink. Most of us hesitate for a second because we have good reading skills and want to say what we’ve read—i.e., “blue.” (You can try the test for yourself here.) In Cohen Kadosh’s version of the test, the volunteers were asked to look at the symbols they had learned—except this time, some of the low-value symbols were written larger than the high-value symbols—and say which of the symbols was larger in size. Students who hesitated were judged to have learned the symbols better than those who did not hesitate.

Volunteers who had received 20 minutes of positive electric current to their brains per day performed best on the test, the team reports online today in Current Biology. Specifically, they hesitated about twice as long as the group that received only 30 seconds of positive current. Students in the group that received 20 minutes of negative current per day were unable to recognize the symbols at all and didn’t respond. The effects of the electrical treatment were retained even 6 months later.

In addition to improving peoples’ numerical skills, electrically stimulating the brain could help patients recover word recognition and motor control after strokes, speculates Cohen Kadosh. And he adds that he sees no reason why this approach can’t be used to enhance word and numbers skills in people with normal math or language ability.

Silke Göbel, a psychologist at the University of York in the United Kingdom, cautions that although the people treated with TDCS may have altered reactions on the Stroop test, the research team has not yet directly shown this improves real-world math skills. “It is not clear whether this effect is really specific to number learning or would generalize to any new stimuli, … [but] this is obviously an important question for future studies”, she says.

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A nervous switch

In 1863 a Heidelberg doctor described a devastating neurodegenerative condition that causes children to forget how to walk and talk before their teens.

The symptoms begin with muscle weakness, poor balance and a slurring of speech, and develop into a gradual breakdown in all motor control.

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A Musical Memory Tour

For many of us, songs by the Beatles trigger vivid and specific memories. What’s going on in our brains when this happens and what makes a tune ‘catchy’? In this show, we go on a musical memory tour to the famous Cavern Club, successor to the Beatles’ first venue, to find the links between memory and music.

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Facial Recognition

How do we recognise faces and are there different ways of doing it in different parts of the World? I researched a piece for BBC Radio Four’s Material World.

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Sound Masking

How has the brain evolved to cope in a noisy world? I investigate how the brain overcomes the problem of sound masking for BBC World Service’s Science in Action.

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Morning sickness may be sign of a bright baby

SICK of morning sickness? Take heart: it may be a sign that your child is developing a high IQ.

Irena Nulman and colleagues at the Hospital for Sick Children in Toronto, Canada, contacted 120 women who years earlier had called a morning sickness hotline. Thirty did not have morning sickness, but the researchers asked the rest to recall the severity of their sickness, and gave the children of all the women, now aged between 3 and 7, a standard intelligence test. Those whose mothers had nausea and vomiting during pregnancy were more likely to get high scores than those whose mothers did not (The Journal of Pediatrics, DOI: 10.1016/j.jpeds.2009.02.005). The reported severity of the vomiting also correlated with the IQ scores.

Morning sickness, which affects most pregnant women, is thought to be a reaction to the hormones human chorionic gonadotropin and thyroxine, which are secreted at unusually high levels during pregnancy to maintain a healthy placenta. Now Nulman speculates that these hormones, which are higher in women who experience morning sickness, may protect the fetus’s developing brain.

Her team found that taking the morning sickness drug Diclectin had no effect on the IQ scores.

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