Archives for February 2010

If all goes well NASA's latest piece of kit - the Solar Dynamics Observatory - will blast off from Cape Canaveral on an Atlas V rocket later today. You can watch the countdown on NASA's launch blog.

The SDO mission is the first in the space agency's new "Living With a Star" programme, and promises to supply unprecedented high-definition images of the Sun's roiling surface, picking out sunspots and solar flares - violent eruptions in the sun's atmosphere known as Coronal Mass Ejections.

Scientists hope the prodigious rush of images that should follow a successful deployment - images with resolution 10 times better than a high definition television - will help them to understand, and improve predictions of, solar activity.

"A Coronal Mass Ejection can carry billions of tonnes of material into space" says the Rutherford Appleton Laboratory's professor Richard Harrison, "Such events can disable satellites, cause power grid failures on earth, and expose astronauts to deadly particle releases".

All the signs are the Solar Dynamics Observatory could be in for a bumpy ride. Images from space telescopes released last week show that the Sun's activity is picking up again after a long period of relative dormancy.

Astronomers have studied the sun for hundreds of years, and the level of solar activity is known to follow a cyclical pattern. It's longest phase of inactivity - known as the Maunder minimum - was in the 17th Century and coincided with a mini ice age.

This latest quite spell - the longest since 1913 - has baffled scientists. No one knows why the Sun's activity should drop off in this way, or when it might "wake up" again.

A key goal for the SDO will be to study the inner workings of the solar dynamo - the deep network of currents that generate the sun's tangled and, at times, explosive magnetic field. It's this dynamo that drives the sun's activity, giving rise to solar flares and the sun spots that meander across its surface.

And if, as scientists believe, the current minimum is coming to an end, the Solar Dynamics Observatory will have its work cut out.

It's hard to imagine anything worse than being trapped in a useless body. Fully aware of what's happening around you, but unable to move or communicate.

That was the situation for the French journalist Jean-Dominique Bauby after a severe stroke left him physically paralysed, or "locked-in". The only function Bauby retained was the ability to blink his left eye - a skill he painstakingly exploited to dictate The Diving Bell and the Butterfly, letter by letter.

It was assumed the patients involved in a new study on Persistent Vegetative States, and published today in the New England Journal of Medicine, didn't even retain that limited level of physical ability or any mental awareness. Unlike locked-in syndrome, patients in a vegetative state appear to be awake, but are unresponsive and there's no sign of intellectual activity.

The team, lead by Dr Adrian Owen at Cambridge University, used a functional MRI scanner to test the brain activity of 23 patients thought to be in a vegetative state.

To their astonishment they were able to detect awareness in four of the subjects, and one man (a 29 year old Belgian who had sustained severe brain injuries in a car accident five years earlier) appeared to understand what was going on in the experiment, and was able to answer a series of questions about is life by directing his thoughts to signal yes or no.

Functional Magnetic Resonance Imaging picks up on minute changes in the activity of protons in the brain.

Thinking about different things produces different patterns of neural activity that can be "read" by the scanner.

In this experiment researchers asked each patient to imagine playing a shot in tennis for yes, and walking from one room to another at their home when they wanted to indicate no.

The discovery has profound implications - not least for the diagnosis of PVS.

"Not only do these scans tell us that the patient is not in a vegetative state" Dr Owen says, "but more importantly, for the first time in 5 years it has provided him with a way of communicating his thoughts to the outside world."

The discovery that some patients previously thought to be in a vegetative state are actually aware of their surroundings might be unsettling for friends and relatives, but the researchers hope it can be exploited to address important clinical questions.

It might be possible for patients to indicate if they are in pain, for instance, or to be consulted over decisions about their treatment.

"It's early days," says Dr Steven Laureys, a co-author from the University of Liege, "but in the future we hope to develop this technique to allow some patients to express their feelings and thoughts, and to increase their quality of life".