Health & Science

New hope for people who are paralyzed

Within the next three years, quadriplegics may learn to walk again by moving a full-body prosthetic device with their minds alone. A team of neuroscientists has taken a giant step toward that goal by teaching monkeys to use their thoughts to operate a virtual arm that sends feedback directly to the brain about the “texture” of things they touch. The new technology could allow paralyzed patients “to get sensations back from their legs, arms, and hands,” Duke University researcher Miguel Nicolelis tells the London Guardian. That sensory feedback is crucial for all kinds of movement, from walking over rocky terrain to grasping a coffee cup. To achieve it, he and his colleagues implanted electrodes in the sensory and motor regions of the monkeys’ brains and attached them to a computer. When a monkey thought about moving its virtual arm, its motor cortex sent signals to the computer to move the limb on-screen. When the arm touched an object, the computer sent return pulses to the sensory cortex: Slow pulses indicated a rough surface, faster pulses a smooth one. The technology may lead to the development of a motorized, full-body exoskeleton that provides sensory feedback, enabling paralyzed people to walk.

A stem cell breakthrough

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A new cloning technique has enabled scientists to turn adult human stem cells into more useful embryonic stem cells—a breakthrough that opens a path to using a patient’s own tissues to grow new organs. In the new technique, scientists insert the nucleus from a patient’s skin cell into an unfertilized egg, which then generates embryonic stem cells that bear the donor’s genetic signature. The process works only when the egg retains its original nucleus, however, so the resulting embryo has an extra set of chromosomes and is not viable for the long term. “It’s an early research step towards curing devastating diseases,” Dieter Egli of the New York Stem Cell Foundation Laboratory tells The Wall Street Journal. He and his team have yet to figure out how to remove the extra set of chromosomes, and some experts have expressed ethical concerns about using human eggs—for which female donors are paid—to create embryos destined only for therapeutic use. But scientists say that cloning embryonic stem cells with adult genetic material will make it possible to create healthy organs and tissue to treat or cure diabetes, Parkinson’s disease, Alzheimer’s, and other illnesses, with minimal risk of rejection. “For the first time we have an experiment that works,” says Egli. “The technical hurdles can be overcome.’’

The perks of envy

Feeling envious may be unpleasant, but it does offer some advantages, The New York Times reports. Psychologists asked college students to write about instances when they’d coveted something belonging to a friend, and then tested their reading comprehension skills. The students who recalled envy were much better at remembering the details of what they read than students who hadn’t done the exercise. Subsequent tests showed that volunteers paid closer attention to stories about people they envied than they did to stories about people they didn’t. The results suggest that envy heightens our powers of memory and observation. “We can’t get our minds off people who have advantages we want for ourselves,” says Sarah E. Hill of Texas Christian University. “It’s much like a car crash we can’t stop looking at.” That single-minded focus may help us learn how to imitate—or sabotage—people we envy in order to win some of their success. But coveting also takes up a lot of energy. Reading about classmates who were rich and good-looking made students quicker to give up on tasks that required prolonged mental effort, like completing puzzles.

Crickets’ lesson in gallantry

Male crickets will risk their lives to protect females, suggesting that chivalry confers an evolutionary edge. Researchers videotaped crickets in the wild for thousands of hours and discovered that if a predator attacks a cricket couple, the male will wait until his partner reaches the safety of a burrow before taking cover himself. That makes male cricket escorts four times as likely to get eaten as single crickets—but guarantees that partnered females are six times less likely to meet that fate. “The consequences of this chivalrous behavior are the same for men and crickets,” Rolando Rodríguez-Muñoz of the University of Exeter in the U.K. tells USA Today. “Both can get more matings and increase their paternity.” Female crickets are more attracted to protectively minded males, who reap an evolutionary benefit from making the ultimate sacrifice: If they can save a female that is carrying their sperm, they ensure that their genes will be passed on to future generations.