I'd never been through an MRI scan before, and this one was anything but routine.

Our assignment was to find a way to illustrate a complex story about patients diagnosed as "vegetative" showing signs of awareness when in a functional MRI scanner.

The story emerged from a study published in the New England Journal of Medicine.

Producer Jonathan Wald immediately set to work ringing hospitals, neurosurgeons, and research centers.

Eventually, we got through to one of the authors of the study.

Dr. Adrian Owen offered to question me while inside the fMRI scanner at the MRC Cognition and Brain Sciences unit at Cambridge– much like what the patients in his study had gone through.

Twenty-three of those patients were believed to be in a so-called "vegetative state;" unresponsive and unaware of their surroundings.

But when asked to imagine playing tennis (meant to activate parts of the brain associated with movement), and walking through the rooms of their homes (meant to activate regions associate with spatial navigation), four of the patients' brains showed a similar response to those of healthy control subjects.

The researchers then went on to ask one of them a series of yes and no questions, imagining tennis for yes, and walking through the house for no.

Incredibly, using only his thoughts, he was able to answer.

We set out to illustrate how the tests were done. So cameraman Andrew Bobbin and I took a pre-dawn train from London to the MRC in Cambridge, in order to use the fMRI scanner early in the morning, the only time it was free.

Dr. Owen had me remove all the metal from my pockets, take off my shoes and jacket, and lie down on the machine. Next, a sort of mirrored visor was placed over my eyes, in which I could see a blue digital rectangle, and I was lowered into the machine.

[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/02/09/t1larg.jpg caption ="MRI scan shows different responses in the brain after the patient is asked different questions."]

For the first ten minutes or so, I was asked to alternate between imagining standing in one spot swinging a tennis racket, and resting under the sun, doing nothing. Next, I was told to imagine walking through the rooms of my house. Only then did we get to the questions.

Dr. Owen asked, "Do you have any brothers or sisters"? He then spoke into the microphone, saying either "answer" - to which I would imagine tennis for yes and navigating my house for no - or "rest".

Though I generated clear enough signals for Dr. Owen to decipher my "yes" answer, it surprised me how difficult it was to think in such a disciplined way for five minutes or so.

For example, I'd be thinking of walking through my childhood home, then suddenly veer off into the neighbors yard and start remembering their old hound dog, or walk into my old bedroom and wonder if that closet door is still broken.

And then, I thought, what a different experience this would be if you were one of the patients in the study. When I was asked every so often if I understood and if I were doing ok, I could respond with no problem.

Not so for the study's patients.

What's more, for those patients diagnosed as "vegetative" but who now appear to be aware, this must have seemed one of the most important tests in their lives.

It was a chance to show not just their loved ones, but the world that they were still inside there - conscious!

Dr. Owen went on to ask a second question, and then we were out of time.

There are many reasons to be cautious about the results of this study, I've been told by doctors and scientists. Further tests need to be done, only those suffering from traumatic injuries responded like the healthy subjects, and only a small percentage of the "vegetative" patients showed signs of cognition.

But none of that has stopped me from wondering at the difference this could potentially make in the lives of some patients, and the possibilities for the future.

We'd like to know what you think - please leave comments or questions below.