Minus one gene, male mouse is Mr. Mom
Instead of killing mouse pups, he makes a nest and gets the pups cozy.
By Science News
WASHINGTON — November 19 was the last day of the Society for Neuroscience annual meeting, which was attended by about 31,000 people.
The day’s highlights include a mouse study showing that one gene can make a difference in gender-based behavior. And a genetic study in humans suggests two genes could play a role in creative ability. A study of rat moms showed long-term cognitive benefits from motherhood, and another study in rats suggests that blinking is anything but random.
The goose becomes the gander, and vice versa
Male mice abandon their homicidal tendencies to become doting parents and accomplished homemakers when a gene is removed from the region of the brain that detects pheromones, new research shows.
Most animals have sex-specific behavior, and male mice are no exception. They make male-specific grunts, they attempt to mate with nearby females and, worst of all, they commit infanticide.
New data presented November 18 by neuroscientist Catherine Dulac showed that removing a gene called Trpc2 from male mice made them act like females. The protein this gene encodes is crucial in the brain for animals to sense pheromones.
Last year, Dulac and colleagues showed the opposite: Females who lack the Trpc2 gene act like males. Irrefutable video evidence showed a female mutant mouse carousing in a cage full of either female or male mice persistently (if unsuccessfully) attempted to sow her wild oats, the team reported in Nature.
“I have to say, the first time I saw these results I just couldn’t really understand what was going on,” Dulac says of the discovery. That observation led the researchers to propose that females had the right connections of neurons in their brains to act like males, and all it took was the right switch — in this case, the lack of Trpc2 — to turn on the male behavior circuit.
In the new research, the scientists tested a mutant male’s maternal instincts by putting him in a cage with a litter of pups. Normally, the male mouse would kill the unfamiliar pups. But while observers waited for the carnage to ensue, the mutant male set about building a nest, then gently picked up each helpless pup and moved it to the new home.
His display of unexpected female behavior showed that in mice, the basis for both male and female behavior probably exists in each animal’s brain, Dulac says. It’s just a matter of activating the right collection of neurons. — Laura Sanders
Creativity may have genetic roots
A study comparing performing artists to people with little or no experience in the arts found that many of the artists inherited variants of two genes involved in novelty-seeking, attention, memory and problem solving. The variants appeared in only one of the non-artists.
These particular genes may influence the development of creative achievement in at least some individuals, across a variety of fields, proposes a team led by Kevin Dunbar and Laura Petitto, both of the University of Toronto.
Variants of the two genes were found in 15 of 58 professional dancers, musicians and actors — about one-quarter of them— versus only one of 36 comparison individuals. The genes, called DRD4 and COMT, influence transmission of dopamine, a chemical messenger in the brain.
“Combinations of genetic variants, rather than specific genetic variants, may be linked to pursuing and achieving expertise in creative activities,” Petitto says.
Brain imaging studies of the same participants indicate that, relative to the comparison group, performing artists display much more activity in a frontal brain region critical for remembering and manipulating different pieces of information at once. This disparity may partly result from intense, long-term practice of creative endeavors by performing artists, in addition to any genetic advantage, Petitto says.
The Toronto researchers plan to look for additional gene variants linked to creative expertise. They also hope to include acclaimed creative virtuosos in their experiments. — Bruce Bower
Babies care for mom
Mothers spend years caring for their young and, it turns out, may get some benefits in return. New findings from University of Richmond researchers show that babies contribute to the long-term cognitive health of their moms.
Previous studies have shown that the hormonal fluctuations that occur during pregnancy, birth and lactation work to remodel the female brain, increasing the size of neurons in some regions and producing structural changes in others.
In recent work with rats, psychologist Craig Kinsley and his students found that the brains of aged females who had given birth possessed fewer deposits of amyloid precursor protein, or APP, a harbinger of Alzheimer’s disease, than did age-matched rats who had not given birth. His group then looked at the cognitive effects of motherhood in rats that were bred to express high levels of APP as they matured. Half of the females were allowed to mate and raise pups, the other half remained virgins.
Behavioral studies showed that the moms performed better at memory and spatial tasks, such as catching prey, than the non-moms. When checking the levels of APP in the brains of the aged females, scientists found that the mother rats had an 11-fold decrease in the amount of protein in their brains.
The new study also showed that the brains of mom rats had higher numbers of estrogen receptors, which are thought to provide some protective benefits in the aging female brain, Kinsley said.
“People often focus on the time and care that mothers give to their young, but this suggests that babies are, in turn, contributing to the long-term welfare of the mother,” he says. — Susan Gaidos
A blinking minute
Humans blink 13,500 times a day on average, but not necessarily randomly, new data from rats suggest.
People blink far more than what is required to maintain moist, healthy eyes. “Spontaneous blinking is not just to maintain a tear film on the cornea. There’s something more there,” says neuroscientist Kyle Horn of Stony Brook University in New York.
Horn found that, in rats, the time increments between blinks vary widely. A rat could blink several times in quick succession and then wait a long period of time before the next blink. But closer analyses of the data showed that an overall pattern of blinks was repeated every 10 minutes.
“Something purely random is not that easy to generate,” says Horn. He and his group think that a relatively simple brain system may control blinking. By mapping the pattern of blinking, the researchers hope to figure out what that system is.
Horn’s team also tested whether factors other than time could make blinking non-random. They found that rats blink more frequently right before and after they groom themselves.
Horn says blinking in people also has behavioral components. People are more likely to blink after finishing a math problem, before and after watching a car whiz by, and before and after looking at a picture, Horn says. The team is also studying blinking in humans. — Laura Sanders
