In Brief

In Brief

Medicine & Science

November 17, 2003

Differences found in brain metabolism of gay, straight men

A new study has for the first time identified differences in brain metabolism of heterosexual and homosexual men.

University of Chicago researchers gave Prozac to a group of eight exclusively gay males and seven exclusively straight men. Then they measured how the Prozac, which increases brain levels of serotonin, affected glucose metabolism in the hypothalamus, which controls sexual behavior.

Presented at last week's annual meeting of the Society For Neuroscience, the study found that the heterosexual group showed a larger decrease in glucose metabolism than the homosexual group. The researchers are not sure whether the difference contributes to sexual orientation or is somehow caused by it.

Flies provide insights into high-speed tracking

Flesh flies gathered from road kill have provided Cornell University scientists with insights into high-speed target-tracking for the U.S. Air Force, which helped pay for the research.

Using high-speed digital photography and imaging software, Cornell entomologist Cole Gilbert was able to create a "view from the cockpit of a fly," tracing the insect's gaze as it swiveled its head like a gun turret in pursuit of female flies.

Despite a tiny brain, the flies tracked and followed the elusive females at speeds of more than 2 meters per second. Scaled up to the size of fighter, that's the equivalent of a hypersonic Mach 12 - 12 times the speed of sound. The work was presented last week at a Society for Neuroscience meeting in New Orleans.

Pollination study may aid in understanding evolution

In a study with implications for our understanding of how species evolve, scientists have found that hummingbirds and bees preferred pollinating two species of monkeyflowers based on the colors of their petals.

Researchers at the University of Washington say hummingbirds pollinated a monkeyflower (like the one above) 70 times more often after the scientists genetically altered its petals so that it retained its shape but changed from pink to orange. Bees normally attracted to the pink monkeyflower shunned the man-made orange variety but favored a species altered from orange to pink. The results were published in Nature last week.

The researchers say the results coincide with Darwin's theory of natural selection but suggest that plants and animals might evolve through sudden, major mutations - such as color change - rather than through more incremental variations over extensive periods.

Studies suggest connection between looking, liking

The more you like something, the more you look at it. And the more you look, the more you like. That's the conclusion from scientists in California and Japan who studied how people form preferences.

In a study published online in the journal Nature Neuroscience, the researchers describe studies of people asked to look at pairs of shapes or faces. The research subjects spent more time looking at the shape or face they eventually came to prefer.

And when the subjects were presented with one of the faces or shapes for more time than the other, people were more likely to say they preferred it.

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