Science News

People who are resuscitated from near death often report strange sensory phenomena, such as memories “flashing before their eyes.” Now a rare assessment of brain activity just before death offers clues about why such experiences occur.

Anesthesiologist Lakhmir Chawla of George Washington University Medical Center and his colleagues recently published a retrospective analysis of brain activity in seven sedated, critically ill patients as they were removed from life support. Using EEG recordings of neural electrical activity, Chawla found a brief but significant spike at or near the time of death--despite a preceding loss of blood pressure and associated drop in brain activity.

In 1970 the Soviet Union put a laser reflector on the moon, carried by a rover. A few months later, it disappeared. Some speculated that the rover had fallen into a crater or parked in such a way as to render the reflector inaccessible. Now, after 40 years on the lunar surface, the reflector has been found.

A team at U.C. San Diego had been searching for it. Earlier this year, NASA’s Lunar Reconnaissance Orbiter camera provided images of the original landing area. A sunlit speck, miles from where the team was looking, turned out to be the rover and reflector. The San Diego team was quickly able to pinpoint the reflector’s location to within 10 meters.

The video my colleagues and I shot is amazing. A blind man is making his way down a long corridor strewn with boxes, chairs and other office paraphernalia. The man, known to the medical world as TN, has no idea the obstacles are there. And yet he avoids them all, here sidling carefully between a wastepaper basket and the wall, there going around a camera tripod, all without knowing he has made any special maneuvers. TN may be blind, but he has “blindsight”--the remarkable ability to respond to what his eyes can detect without knowing he can see anything at all. [To see the film of the experiment, go to www.ScientificAmerican.com/may2010/blindsight .]

TN’s blindness is of an extremely rare type, caused by two strokes he suffered in 2003. The strokes injured an area at the back of his brain called the primary visual cortex, first on his left hemisphere and five weeks later on the right. His eyes remained perfectly healthy, but with his visual cortex no longer receiving the incoming signals he became completely blind.

Eat less saturated fat: that has been the take-home message from the U.S. government for the past 30 years. But while Americans have dutifully reduced the percentage of daily calories from saturated fat since 1970, the obesity rate during that time has more than doubled, diabetes has tripled, and heart disease is still the country’s biggest killer. Now a spate of new research, including a meta-analysis of nearly two dozen studies, suggests a reason why: investigators may have picked the wrong culprit. Processed carbohydrates, which many Americans eat today in place of fat, may increase the risk of obesity, diabetes and heart disease more than fat does--a finding that has serious implications for new dietary guidelines expected this year.

In March the American Journal of Clinical Nutrition published a meta-analysis--which combines data from several studies--that compared the reported daily food intake of nearly 350,000 people against their risk of developing cardiovascular disease over a period of five to 23 years. The analysis, overseen by Ronald M. Krauss, director of atherosclerosis research at the Children’s Hospital Oakland Research Institute, found no association between the amount of saturated fat consumed and the risk of heart disease.

After the death of her mother, Rosie had a fitful night, tossing and turning and getting up frequently. [More]

When physicists puzzle out the workings of some new part of nature, that knowledge can be used to build devices that do amazing things -- airplanes that fly, radios that reach millions of listeners.  When we come to understand how brains function, we should become able to build amazing devices with cognitive abilities -- such as cognitive cars that are better at driving than we are because they communicate with other cars and share knowledge on road conditions.  In 2008, the National Academy of Engineering chose as one of its grand challenges to reverse-engineer the human brain.  When will this happen? Some are predicting that the first wave of results will arrive within the decade, propelled by rapid advances in both brain science and computer science . This sounds astonishing, but it’s becoming increasingly plausible. So plausible, in fact, that the great race to reverse-engineer the brain is already triggering a dispute over historic “firsts.” [More]