Poor Mojo's Newswire

The evolutionary primacy of the brain's fear circuitry makes it more powerful than the brain's reasoning faculties. The amygdala sprouts a profusion of connections to higher brain regions -- neurons that carry one-way traffic from amygdala to neocortex. Few connections run from the cortex to the amygdala, however. That allows the amygdala to override the products of the logical, thoughtful cortex, but not vice versa. So although it is sometimes possible to think yourself out of fear ("I know that dark shape in the alley is just a trash can"), it takes great effort and persistence. Instead, fear tends to overrule reason, as the amygdala hobbles our logic and reasoning circuits. That makes fear "far, far more powerful than reason," says neurobiologist Michael Fanselow of the University of California, Los Angeles. "It evolved as a mechanism to protect us from life-threatening situations, and from an evolutionary standpoint there's nothing more important than that."

Now Christopher Doughty at the University of California, Irvine, and colleagues think they can get around that problem. Models show that geoengineering near the equator hits rainfall hardest, but focusing on latitudes between 30 and 60 degrees would produce a much smaller drop in rainfall. Planting crops bred or genetically modified to be more reflective could cool these regions by an average of 1 degree C. Doughty presented the research last month at the American Geophysical Union meeting in San Francisco.

The key, Doughty says, is to deploy leaves that sport a thick layer of hairs, which reflect near-infrared wavelengths back out into space. Super-hairy strains of soya have already been bred, and these reflect 3 to 5 per cent more sunlight. Doughty calculates that this would be enough - if planted in huge amounts - to generate the cooling effect.

The drugs most widely used to manage aggressive outbursts in intellectually disabled people are no more effective than dummy pills for most patients and may be less so, researchers report.

The finding, published Friday, sharply challenges standard medical practice in mental health clinics and nursing homes in the United States and around the world.

In recent years, many doctors have begun to use the so-called antipsychotic drugs, which were developed to treat schizophrenia, as all-purpose tranquilizers to settle threatening behavior - in children with attention-deficit problems, college students with depression, older people with Alzheimer's disease and intellectually handicapped people.

The new study tracked 86 adults with low IQs in community housing in England, Wales and Australia over more than a month of treatment. It found a 79 percent reduction in aggressive behavior among those taking placebo pills, compared with a reduction of 65 percent or less in those taking antipsychotic drugs.

HOUSTON (AP) — Two Baylor College of Medicine researchers in Houston are working on a cocaine vaccine they hope will become the first-ever medication to treat people hooked on the drug. "For people who have a desire to stop using, the vaccine should be very useful," said Dr. Tom Kosten, a psychiatry professor who is being assisted in the research by his wife, Therese, a psychologist and neuroscientist. "At some point, most users will give in to temptation and relapse, but those for whom the vaccine is effective won't get high and will lose interest."

The vaccine, currently in clinical trials, stimulates the immune system to attack the real thing when it's taken.

The immune system — unable to recognize cocaine and other drug molecules because they are so small — can't make antibodies to attack them.

To help the immune system distinguish the drug, Kosten attached inactivated cocaine to the outside of inactivated cholera proteins.

In response, the immune system not only makes antibodies to the combination, which is harmless, but also recognizes the potent naked drug when it's ingested. The antibodies bind to the cocaine and prevent it from reaching the brain, where it normally would generate the highs that are so addictive.

Parents may now have another reason to worry about their children smoking. Nicotine may cause the teenage brain to develop abnormally, resulting in changes to the structure of white matter - the neural tissue through which signals are relayed. Teenagers who smoke, or whose mothers smoked during pregnancy, are also more likely to suffer from auditory attention deficits, meaning they find it harder to concentrate on what is being said when other things are happening at the same time.

Leslie Jacobsen of Yale University School of Medicine and colleagues used diffusion tensor imaging, which measures how water diffuses through brain tissue, to study the brains of 33 teenagers whose mothers had smoked during pregnancy. Twenty-five of the teens were daily smokers. The team also studied 34 teens whose mothers had not smoked, of whom 14 were daily smokers.