Have you read William Saletan's piece in the September 12th edition of Slate?

The wheels lock, the car skids, you see the 18-wheeler heading for your windshield. You have just enough time to open your mouth. Then the bite of glass and metal, and merciful blackness.

Somebody's talking. You try to open your eyes, but nothing happens. You can't move or feel anything.

...You try to call out, to scream. No one knows you're here, awake inside your skull. No one will ever know.

Saletan's frightening opener was inspired by a report in last week's edition of Science. Seems a group of British scientists used a Functional Magnetic Resonance Imaging scanner to track blood flow to different parts of a "vegetative" young woman's brain. Surprise! "The scan lit up with telltale patterns of language, movement, and navigation indistinguishable from the brains of healthy people."

What does this mean? Well, one thing it doesn't mean is that Terri Schiavo was mentally alert when doctors ceased extreme measures to keep her alive.

The English patient had several factors in her favor: Her injury was traumatic, her brain was largely intact, and she had been vegetative for only a few months. At the other end of the spectrum are people such as Terri Schiavo. Their injuries are caused by oxygen starvation, their brains are liquefied, and they've been vegetative for years.

However, Saletan offers some troubling statistics and questions:

By various estimates, 25,000 to 35,000 Americans have been diagnosed as vegetative. How many of them have received FMRI scans? How many would light up? How many are awake in there?

You might want to read the whole article. It's definitely food for unsettling thoughts.