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What nightmare could be worse than being buried alive? Conscious, terrified, but unable to communicate through the impenetrable barrier of a coffin lid and a metre of earth. In the past few days, this ultimate horror has been transformed from the stuff of bad dreams and B movies to two very different front page stories.
First, the uplifting images of people being pulled from the rubble of Haiti, up to 15 days after the earthquake. The joy of seeing those individual miracles provided a thin veneer over the unthinkable thoughts about the thousands who must have died, unrescued.
And now there is the extraordinary report from neuroscientists who have used a brain scanner to communicate with a very different kind of trapped victim - a patient in a Persistent Vegetative State. Let’s be clear about what they did. The technique they used, functional Magnetic Resonance Imaging (fMRI), doesn’t record brain activity directly. It detects signals related to changes in the flow of blood within the brain, in response to the local demands of active nerve cells, hungry for oxygen and glucose. Clever computer programs turn such measurements into those now-familiar pictures, looking like something you might see in a fancy restaurant in Lyon or Strasbourg - a slice of brain in aspic decorated with red and yellow blobs.
Brains consist of nerve cells, one thousand million of them, each less than a fiftieth of a millimetre in size, connected together by a monstrous tangle of nerve fibres. And these nerve cells chatter to each other by sending tiny electrical impulses, each about one-tenth of a volt lasting just one thousandth of a second. That is the real scale on which the brain works, at least on which its calculations and computations are performed.
The red and yellow blobs reflect the slow and more widespread changes in blood flow that follow the frenetic activity of nerve cells. Interpreting the blobs is comparable to trying to work out the exchange of gossip and banter between the spectators at a football match by watching movement in the terraces from the opposite side of the stadium.
Brain scanning is not going to tell us how the brain works - at least not in the kind of detail an engineer would want. But it does provide a window into the previously private world of the human mind. It can at least tell us which parts of the brain are active as a person sees, hears, thinks, remembers, plans and carries out actions.
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