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.
If the scientists had been trying to read hidden intentions, this would be cheating. But their aim was exactly the opposite. They were looking for deliberate activity—the signature of a living, choosing mind. The patients couldn't produce physical activity, as you or I would. But they could produce mental activity. They could use the brain as a kind of tablet, writing "tennis" on their supplementary motor area or "navigation" on their parahippocampal gyrus. That's the real genius of the European study: The mind can use the brain as a communication device.
Before brain scans, this was impossible. Nobody could see your brain. Thinking was one thing; doing was another. Scans have abolished that distinction. They have illuminated the paradoxical world of cognitive acts. We can ask you to think about tennis, and the scan will show whether you've done it. The European scientists' report, published in the New England Journal of Medicine, brings us a strange new language in which patients "perform imagery tasks" and then "rest" between thoughts. The criteria by which patients prove they're aware—interaction, communication, purposeful response—have been redefined to include mental feats. Scans, the authors explain, can take us beyond "behavior that is readily observable" to something deeper: behavior within the brain.
But this inner behavior, in turn, is only a clue to something still deeper. Look at the title of the scientists' report: "Willful Modulation of Brain Activity in Disorders of Consciousness." The purpose of the scans is to detect the will. To make itself detectable, the will must generate activity. If activity can't be found in the visible body, we must look for it in the brain. It isn't the brain we're after. It's the person using it.
Everything the scientists did was designed to detect the will. They instructed patients to concentrate on tennis or navigation for a full 30 seconds because no unwilled brain blip could last that long. According to the report, the patients' success in doing this demonstrates their "sustained involvement in the task." The scientists also made the instructions to patients somewhat complicated so that their responses would "depend on the patient's conscious decision (or 'mindset') about which answer to give."
In other words, the patients had a choice. They could write the requested answer on their brains, or they could write something else, or perhaps nothing. Four years ago, when members of the European team reported their first successful scan of a pseudo-vegetative patient, they observed that "her decision to cooperate with the authors by imagining particular tasks when asked to do so represents a clear act of intention." In their latest report, they make the same point: "Participants were asked to respond by thinking of whichever imagery corresponded to the answer that they wanted to convey." Even when every other power is gone, you can refuse to cooperate. On the tablet of your brain, you can write whatever answer you want.
So cheer up. Brain scans have brought you a whole new way to communicate—or to tell your interrogators to go to hell. Human Nature's latest short takes on the news, via Twitter: