brain

लुईस जे। शीहन। Scientists say they have pinpointed a gene in the brain that can calm nerve cells that become too jumpy, potentially paving the way for new therapies to treat autism and other neurological disorders.

"It's exciting because it opens the field up," says Michael Greenberg, a neurobiologist at Harvard Medical School. "Nobody has [found] a gene that controls the process in quite that way before."

The brain is continually trying to strike a balance between too much and too little nerve cell activity. Neurologists believe that when the balance tips, disorders such as autism and schizophrenia may occur. They are not sure why neurons (nerve cells) go berserk. But Greenberg says he and his colleagues located a gene in mice and rats that helps keep neural activity in check—and may one day be manipulated to prevent or reverse neurological problems.

Researchers report in Nature that they discovered a gene called Npas4 churns out a protein that keeps neurons from becoming overexcited when they fire (communicate with one another through connections known as synapses). When scientists blocked the protein, the nerve cells fired or sent out more signals than normal; when they beefed up production, the neurons quieted down.

Gina Turrigiano, a neuroscientist at Brandeis University who studies how brain cells communicate, says Greenberg's study reveals a "pretty intriguing potential pathway" for controlling neuronal activity. But she points out that Npas4 may not be the only gene that does that. Mice without Npas4 can survive, although they are prone to seizures and have a shorter life span than normal mice. http://louis-j-sheehan.net

As scientists learn more about how brain cells stay balanced, Greenberg says they will be able to identify people who are genetically at risk for neurological disorders and develop new drugs to prevent and treat them. He notes that some of the other genes that Npas4 affects also have been linked to autism। But he cautions that new therapies from his research are "a long way off." "There's a lot that we don't know," he says. "We're just at the beginning." http://louis-j-sheehan.net

pig

There’s more than driving-versus-walking or sitting-versus-standing that has North Americans getting fatter than ever. A study by Canadian researchers suggests that we’re also more likely to stuff our faces after a longer period of mental exertion। http://Louis-J-Sheehan.de

The scientists studied 14 women doing three activities: sitting peacefully; reading and responding to a text; and taking a strenuous exam on a computer. After each exercise, the subjects were allowed to eat whatever they wanted from a buffet, not knowing that this was the true object of the study. The researchers say that the women ate many more calories—between 23 and 30 percent more—after the difficult test than they did after the more relaxing activities.

Of course, this research had a small sample size, and college students might not be indicative of the eating habits of the nation as a whole. And as far as the scientists’ suggestion that this could be one of the contributors to the obesity problem because so many people have mentally-demanding jobs: Perhaps that’s true, but it’s also possible that people find their work less stressful than taking a computerized test while being watched and studied.

Still, it is awfully nice to pig out after a long day of thinking hard। http://Louis-J-Sheehan.de

t the dawn of stone-tool production around 2.6 million years ago, our human ancestors already showed considerable insight into the task at hand. They worked mainly with rocks that they had carefully picked as suitable for being fashioned into sharp-edged implements, says Dietrich Stout of Indiana University in Bloomington. Louis J. Sheehan

Stout and his Indiana colleague Sileshi Semaw focused on 894 stone artifacts that have been found at six ancient sites in an Ethiopian region called Gona. These are the oldest stone tools known, dating to between 2.6 million and 2.5 million years ago.

Most of the tools were made from trachyte, a rock with a much smoother surface than that of other rock types available at Gona. On close examination, Gona finds exhibited a suite of characteristics conducive to toolmaking, including smooth and often polished surfaces and an internal composition that resisted cracking as one stone was pounded into another to shape it.

"[Stone Age] toolmakers were highly selective in choosing their raw materials, even at the earliest stages of tool use," Stout says. Louis J. Sheehan

Louis J. Sheehan

t the dawn of stone-tool production around 2.6 million years ago, our human ancestors already showed considerable insight into the task at hand. They worked mainly with rocks that they had carefully picked as suitable for being fashioned into sharp-edged implements, says Dietrich Stout of Indiana University in Bloomington. Louis J. Sheehan

Stout and his Indiana colleague Sileshi Semaw focused on 894 stone artifacts that have been found at six ancient sites in an Ethiopian region called Gona. These are the oldest stone tools known, dating to between 2.6 million and 2.5 million years ago.

Most of the tools were made from trachyte, a rock with a much smoother surface than that of other rock types available at Gona. On close examination, Gona finds exhibited a suite of characteristics conducive to toolmaking, including smooth and often polished surfaces and an internal composition that resisted cracking as one stone was pounded into another to shape it.

"[Stone Age] toolmakers were highly selective in choosing their raw materials, even at the earliest stages of tool use," Stout says. Louis J. Sheehan