Here's a real-life horror story: Five people have been found buried alive inside their bodies. Paralyzed by brain injuries, they lay inert for years, seemingly oblivious to the doctors and loved ones around them. Four were diagnosed as vegetative. Then a European research team scanned their brains. It turns out they're aware; they just can't speak or move. God knows how many more are trapped like this.
On the heels of this frightening idea comes another: The scans that exposed these patients' thoughts could expose yours. They could read your mind. "Governments are interested in the thoughts of their citizens—whether their voting intentions or their propensities to crime," warns Colin Blakemore, an Oxford neuroscientist. In the European scans, he sees "the possibility that brain science could bring an era of surveillance that will make the epidemic of CCTV cameras look trivial."
Relax. The brain scans are wonderful news. The patients were trapped anyway; the scans have simply restored their ability to communicate. Better yet, that communication remains voluntary. Without the patients' cooperation, the scans would have found nothing. That's the most marvelous thing the scans have discovered: Human minds stripped of every other power can still control one last organ—the brain.
In the age of neuroscience, this sounds ridiculous. We think of the brain as its own master, controlling or fabricating the mind. The New York Times, for instance, says that when the first pseudo-vegetative patient was scanned, "areas of her motor cortex leapt to life," and "spatial areas in the brain became active"—as though these areas animated themselves. The Times of London calls the organ in the scans "the talking brain." Blakemore sees the scans as part of a new understanding: Our intentions, far from guiding of our behavior, are really just products of brain cells that have already "made up their minds."
If the brain controls the mind this way, then brain scanning seems like mind reading. The Washington Post says the European scans enabled scientists to "peek inside the minds" of the patients. The London Independent says the scientists "read the minds of the living dead." Blakemore thinks such scans will soon detect not just lies but intentions, now that technology can "see inside the heads (and hence the minds) of living people."
It's fun to spin out these neuro-determinist theories and mind-reading fantasies. But the reality of the European scans is much more interesting. They don't show the brain controlling the mind. The patients' brains didn't talk; their motor cortexes didn't leap to life; their neurons didn't "make up their minds." The scans show the opposite: the mind operating the brain.
The scans rely on functional magnetic resonance imaging (fMRI), which maps the distribution of blood oxygen—a proxy for cellular activity—across brain regions. They're far too coarse to differentiate neurons or discern hidden intentions. But they can detect gross categorical differences. For example, they can distinguish activity in the area that processes navigation from activity in the area that processes motor commands. In an open-ended test, they can't tell that you're imagining playing tennis. But if you alternate between two prescribed thoughts—playing tennis and walking through your house—they can tell which is which.
That's why the European scientists used tennis and navigation to do their scans. They asked each patient to imagine swinging a tennis racket. Then they asked him to imagine navigating his home or his city. In essence, they asked the patients to generate the kinds of brain activity scans can read.
Then the scientists put one patient through a further experiment: They asked him several yes-or-no questions about his life. But brain scans can't distinguish "yes" from "no." So they asked him to say "yes" by imagining tennis and to say "no" by imagining navigation. The machine needed translation assistance from the paralyzed human being.