SCIENCE

Pronghorn antelope trying to migrate between calving and wintering grounds have lost many of their routes to development.
Pronghorn antelope trying to migrate between calving and wintering grounds have lost many of their routes to development. (By Julie Larsen Maher -- Copyright Wildlife Conservation Society)
Monday, July 17, 2006

Brain to Computer to Action

An electronic array implanted in the brain of a 25-year-old man paralyzed from the neck down has allowed him to use his brain signals to take actions such as opening e-mail and manipulating a computer mouse, scientists report.

While such brain-to-computer devices are still far from being able to mimic what humans can do in terms of fine control, precision and speed, they offer hope that people with spinal cord damage and other serious problems might one day regain important aspects of autonomy and functioning.

Scientists at Massachusetts General Hospital and other academic institutions said the system developed at Cyberkinetics Neurotechnology Systems Inc. is remarkable not just as a technological marvel but also because it shows that the brain is capable of sending out signals years after a severing of its connection to the limbs.

Shortly after the device was installed and calibrated, the patient was able to play a simple video game, read e-mail and control a television set.

A report on the case was published last week in the journal Nature, along with an article detailing a technique that seeks to convert an even earlier stage of brain activity into action. By picking up brain signals at the level of intentions instead of waiting until the brain begins to direct physical movement, scientists at Stanford University hope to allow patients one day to complete actions without even having to think about the action itself.

-- Shankar Vedantam

Migration Corridors Disappear

The mammals who make the longest overland migration in the continental United States may disappear from the ecosystem of Yellowstone and Grand Teton national parks, according to a study in the latest issue of the journal Biology Letters.

A herd of pronghorn antelope, which for more than 6,000 years have journeyed at least 400 miles between their calving and wintering grounds, is being squeezed out of its migration routes by development and human disturbance outside the parks. Scientists from the Wildlife Conservation Society and the National Park Service found that six of the antelopes' eight migration corridors in and out of the Yellowstone ecosystem have disappeared, and the animals must now pass through bottlenecks that are not much wider than a football field.

"It's amazing that this marathon migration persists in a nation of almost 300 million people," said lead author Joel Berger, a researcher at the Wildlife Conservation Society. "At the same time, the migration is in real trouble and needs immediate recognition and protection."

While the herd is small at this point -- it numbers between 200 and 300 -- the researchers wrote that saving its migration route would be "more than symbolic" and that if it is obstructed, "whether by petroleum development, housing or other factors, an entire population from a national park could be eliminated, leaving a conspicuous gap in the ecology and function of native predator-prey interactions."


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