MIT researchers and their colleagues at University College London have become the first to report that sensations of touch can be jointly experienced by individuals an ocean apart. The experimental set-up the researchers used has robotic arms that convey a sense of touch to the user’s fingers. The arms are tied into a computerized transmission system that is in turn linked to a specialized, high-capacity Internet system, says Mandayam Srinivasan, a senior research scientist and head of the MIT group involved. In initial tests of the system, users in Cambridge and London worked together to “lift” a box that in fact existed only as a virtual object shown graphically on screens in both sites. As the experimenters cooperated, they not only experienced the force exerted by the box on their own hands but were aware of the forces of the other users’ hands. The advance improves prospects for a range of applications, among them letting surgeons who perform long-distance operations experience the feel of their robotic instruments at work. Barriers to such applications remain, though, including the fact that even modest Internet delays can significantly affect the quality of the forces that individuals thousands of miles apart may experience.
One of the most frightening medical phenomena in the news is so-called mad cow disease — formally known as bovine spongiform encephalitis (BSE) — and ailments like it. The diseases, some of which afflict both humans and animals, cause a terrifying syndrome that has much in common with real madness. What makes them especially unnerving is that they seem to be caused by an infectious agent whose exact character has largely eluded scientists. Now, though, MIT biologist Susan Lindquist and a colleague currently at Ohio State have dispelled much of the mystery. The researchers’ key finding is that a specific type of protein dubbed the prion protein can become structured in abnormal ways. Our bodies have built-in machinery for eliminating these malformed troublemakers, but in rare cases some proteins escape the effects of the disposal system. They then not only poison the cell they inhabit but can also convert other prion proteins into disease-causing agents. But why has it been so tough to figure out BSE’s origins? Lindquist, who is also director of the MIT-affiliated Whitehead Institute for Biomedical Research, says “we think the toxicity wasn’t realized before because such small amounts of the abnormal protein are required for cell death.”
DREAMS AND LEARNING
Sleep problems are epidemic in our pressurized modern world, yet the full costs of all this tossing and turning are far from clear. While it’s well-known, for example, that the sleep-deprived are at greater risk than others for problems like highway accidents, the question of how and why chronic sleep problems impair someone’s ability to carry out cognitive tasks like learning and remem-bering is poorly understood. In work that could shed light on such issues, MIT neuro-scientist Matthew Wilson of the Picower Center for Learning and Memory has discovered that rats tested during so-called slow-wave sleep — the most extensive part of the sleep cycle in both rats and humans — seem to be revisiting the prior days’ events in their brains during that phase of sleep, but with some fascinating wrinkles. Careful measurements of selected brain cells, for example, showed that the animals’ brains essentially boiled down an activity — one lap around a lab track — which takes four seconds in real time into a dream replay that lasted a scant 100 to 200 thousandths of a second. The study, combined with an earlier look at so-called rapid-eye-movement (REM) sleep, suggests that even a modest disruption of key segments of the sleep cycle could seriously disrupt the learning process. And the slow-wave phase has one key quality not shared by dreams that happen during REM sleep, says Wilson. “The slow-wave sleep replays only occurred during the period of sleep immediately following the animals’ turns around the track,” he notes.
PROBING COSMIC BURSTS
A satellite developed by an MIT-led team has permitted the most up-to-the-minute study yet of one of nature’s most awesome events. The event is called a gamma ray burst because its main product is a massive outpouring of these ultra-high-energy X-rays. The bursts are thought to stem from either a massive star’s explosion — a cataclysm far bigger than the more familiar supernova –– or from a collision between two of the extremely high-density bodies called neutron stars. In either case, these bangs carry a lot of punch, with energies at about those of a billion trillion suns –– and in both cases the end product is a so-called black hole, a cosmic body so dense even light can’t escape. Because the bursts last only seconds, and their after-glow lasts a few hours at most, it has been hard to spot them early enough to study immediate post-explosion activities. Late last year, though, the High-Energy Transient Explorer (HETE) satellite transmitted word of a burst to tracking stations around the world. Caltech astronomer Derek Fox — an MIT graduate — was the first to home in on the explosion, identifying its after-glow just 20 minutes after the HETE transmission, or well before the glow died away. The early spotting also allowed other astronomers to probe not only the burst itself but the galaxy in which it originated. Among other things, the studies may shed light on the origins of black holes. “This was the one that didn’t get away,” says George Ricker, the senior scientist at MIT’s Center for Space Research who led the HETE development team.