What we do know is that the fetal brain does not even begin to develop until three to four weeks after conception, so the most basic building blocks of pain perception, the scaffolds of consciousness, do not exist before then. The major divisions of the adult brain emerge at four to eight weeks into pregnancy, but only after about eight weeks does the cerebral cortex separate into two distinct hemispheres. At twelve weeks, rudimentary neuronal connections are emerging between different parts of the brain, but these are not sufficient to support conscious experience.

  As Daniel Bor argued in his excellent 2012 book, The Ravenous Brain, the areas of the brain that need to be intact, functional, and able to communicate with one another for conscious awareness to occur do not get properly laid out until about twenty-nine weeks into the pregnancy, and it’s another month before they are communicating effectively. On the basis of the science then, it’s highly unlikely that consciousness in any form, including the ability to experience pain, emerges before about thirty-three weeks after conception.

  Detractors point out that a fetus as young as sixteen weeks responds to low-frequency sounds and light. Indeed, by nineteen weeks a fetus may flinch or withdraw a limb in response to a painful stimulus. These are persuasive signs, and it’s understandable why they are often taken as evidence for emerging consciousness. However, as Daniel says in his book, these responses are generated by the most primitive parts of the brain, which are unconnected to consciousness, and do not therefore in any way imply that the fetus is aware. What we are witnessing are early reflexes, probably controlled entirely by a primitive brain stem and spinal cord, to a set of physical circumstances and conditions. Someone with a religious orientation might point out—with some justification—that this view still doesn’t explain what makes consciousness happen. It’s almost as if a mysterious switch were flipped on. Precisely because we don’t fully understand how or when that switch is turned on, God’s will—his “grand design”—is often invoked as an explanation.

  As a scientist who has devoted much of my life to understanding whether consciousness exists in people in extremis, I think such arguments are entirely spurious. That we don’t yet know what makes consciousness happen has no bearing on whether it can be physically explained. Indeed, I have no doubt that these things will be understood and explained in the near future, just as many of the other great mysteries of the universe have in recent years been explained by physics. As scientists, we collect data, we generate hypotheses, and we test those hypotheses. Sometimes we solve the problem and explain something new, and sometimes we don’t. But whether or not we solve the problem today has no bearing on whether it is solvable. Falling back on metaphysical explanations just because we haven’t yet found the physical answers is antiscientific, illogical, and, to my mind, irrational. After all, if we did that all the time, we’d still be trying to avoid sailing off the edge of our flat earth!

  Just as we were wrestling in Cambridge with the question of whether Debbie was conscious and looking hard at when consciousness begins, it appeared that an entire country on the other side of the Atlantic was going to war over when consciousness ends. The gray zone was suddenly the lead story on the US evening news, and word quickly spread to our side of the pond. Somehow, a perfect storm erupted: the right patient, the right family, the right disagreement, and the right amount of public interest in an issue that had, until then, garnered precious little media attention. The right-to-life and the right-to-die movements faced off over one woman who had been declared vegetative and lay in her hospital bed, apparently unaware that half a nation was going to bat for her. Theresa Marie “Terri” Schiavo had had a cardiac arrest at her Florida home in 1990 and sustained massive brain damage from prolonged oxygen deprivation. In 1998, her husband, Michael, petitioned the Florida courts to remove her feeding tube so that she would be allowed to die. Terri’s parents, Robert and Mary Schindler, opposed him, arguing that their daughter was conscious.

  Cambridge looked on agog. Book deals were signed, documentaries shot, the family appeared on reality TV, lawsuits were launched, protesters for both the right-to-life and right-to-die movements took to the streets, the press seethed. To us Brits it was simply absurd. You might well imagine the conversation over tea and croquet.

  “Well, at least the president’s not involved.”

  “Oops! The president is involved.”

  With the Monica Lewinsky–Bill Clinton debacle and the O. J. Simpson trial recently behind us, we had warmed up to the idea that the American legal system is unpredictable at best and occasionally absurd.

  As if to accentuate the contrast, Britain was recovering from its own Schiavo debacle, which lacked the circuslike atmosphere of Florida but was nonetheless heart wrenching. Anthony Bland, a twenty-two-year-old supporter of the Liverpool soccer team, was injured in the Hillsborough stadium disaster—a stampede that had killed ninety-six people in 1989. Bland’s case preoccupied the country for months and the courts for years. Fans blamed the police; the police blamed the fans. Bland suffered severe brain damage that left him in a vegetative state. The hospital, with the support of his parents, applied for a court order that would allow him to “die with dignity.”

  The judge, Sir Stephen Brown, ruled, for the first time in an English court, that artificial feeding through a tube is medical treatment and that to discontinue treatment would be in accordance with good medical practice. Opposition was immediate, but of a very British sort. The lawyer appointed by the Official Solicitor to act on Bland’s behalf argued that to withdraw food from him would be tantamount to murder and appealed the decision. The appeal was rejected by the House of Lords.

  In 1993, Bland became the first patient in English legal history to be allowed to die by the courts through the withdrawal of life-prolonging treatment, including food and water. There was relatively little opposition, not much fuss, just a rather sober treatment by the media, who noted that times had now changed and in cases where there “was no hope” patients should be allowed to exercise their right to die.

  It was a peculiarly British way of doing things. Respectful, mournful, and stoic, with no more than a modest departure from standard protocol. In April 1994, pro-life campaigner Father James Morrow did attempt to get the doctor who withdrew food and drugs from Anthony Bland charged with murder, but the petition was quickly rejected by the High Court.

  This was not at all the atmosphere or attitude in the United States, where the party was in full swing. In 2003, “Terri’s Law” passed in Florida, which gave Governor Jeb Bush the authority to intervene in the case. Bush immediately ordered the reinsertion of Schiavo’s feeding tube, which had been removed a week earlier.

  The Schindlers created more publicity by lobbying to keep their daughter alive. They selected a notable pro-life activist, Randall Terry, as their spokesman and continued to pursue their available legal options. The madness escalated. The case drew the attention of everyone with a microphone and a mouth.

  Finally, in 2005, a court allowed Schiavo’s husband, Michael, to pull the plug for good. In all, the case involved fourteen appeals and numerous motions, petitions, and hearings in the Florida courts; five suits in federal district court; extensive political intervention by the Florida state legislature, Governor Jeb Bush, the US Congress, and President George W. Bush; and four denials of certiorari from the Supreme Court of the United States. As legal expert David Garrow put it in the Baltimore Sun, “The most-reviewed and the most-litigated death in American history” was over.

  Schiavo’s autopsy revealed widespread brain damage, with profound shrinkage to key cortical regions. After an injury or a prolonged period without oxygen, brain cells often die off and never get replaced. This is called apoptosis, a common pattern in vegetative-state patients. Damage to parts of Schiavo’s cortex critical for higher aspects of cognition—thinking, planning, understanding, and making decisions—makes it quite clear that she retained no semblance of awareness. The basic building blocks of cognition, the scaffolds upon which our consciousness is supported, had been demolished.

  Understanding whether Terri Schiavo was conscious is not like understanding whether a one-month-old is conscious. While one-month-olds’ behavior is confusing, they do have the neural machinery that is required for consciousness to exist whether it is there or not. Schiavo had neither the machinery nor the potential. She was not in the gray zone. The person who was born Theresa Marie Schindler in Montgomery County, Pennsylvania, a shy woman who had married her first love, Michael Schiavo, did not exist anymore and never would. What had replaced that person? It was hard to say. What was indisputably clear was that Terri Schiavo was long gone.

  The Schiavo case crystallized public awareness of the gray zone. It brought brain injury and science into the courtroom for the first time on a mass scale in an explosive frisson of science, law, philosophy, medicine, ethics, and religion. I realized that by investigating the gray zone, we were really investigating what it means to be alive. We were exploring the border between life and death. We were right at the nexus of trying to figure out the difference between a body and a person, the difference between a brain and a mind. As the great Francis Crick, a physicist and molecular biologist, wrote in his seminal 1994 book, The Astonishing Hypothesis, “You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules.” Only a few years later, we were beginning to uncover how that three-pound lump of gray and white matter in our heads generates every thought, feeling, plan, intention, and experience we ever have.

  CHAPTER SIX

  PSYCHOBABBLE

  The limits of my language mean the limits of my world.

  —Ludwig Wittgenstein

  As the “right to live” versus “the right to die” divided two nations, we were busy trying to build a body of evidence that would help us to understand the minds of people like Terri Schiavo and Anthony Bland. We needed more evidence; more reliable evidence. Evidence that was completely incontrovertible. The Schiavo circus had made that abundantly clear. I was convinced that the stakes of what we were doing were even higher—if we could parse what enabled Debbie’s and Kate’s brains to respond to our “stimulation,” we would be on the road to cracking the code of consciousness itself.

  Our next step was to design an experiment that would allow us to conclude that a patient like Debbie or Kate had the capacity to understand language. We knew their brains could process speech, but did they, the people inside, have any sense of what that speech actually meant?

  Ingrid Johnsrude and her colleagues Jenni Rodd and Matt Davis were working on exactly this problem at the Unit, pinpointing which parts of our brains are responsible for understanding spoken language. The reasoning behind one particular experiment was elegant and—in true Unit tradition—a little quirky. If they submerged speech in a sea of static noise, then those parts of the brain responsible for understanding language would have to work harder to extract meaning from what was being heard and thereby make themselves known on a PET scan. They were constructing experiments that were similar to turning the frequency dial on a car radio, looking for a decent signal. Sometimes you’ll chance upon a station where people are talking about something of great interest to you, but the reception is terrible and you can hardly make out what is being said. The lure of the subject matter keeps you listening, but you have to strain to decipher the content of the conversation from the background noise.

  Ingrid and her colleagues created a situation almost exactly like that in the PET scanner for a group of healthy volunteers. They were played sentences that varied in terms of their “intelligibility.” The amount of static noise, relative to clear speech, was adjusted so that some of the sentences were easily understood, some could be deciphered with a bit of extra effort, and some were almost incomprehensible. As the sentences became increasingly difficult to decipher, activity increased in an area of the temporal cortex on the left side of the brain. The more difficult the sentences were to understand, the harder this region of the brain had to work, and this showed up on the PET scan as more and more radioactive blood rushed to that region to replace used-up energy.

  My psycholinguist friends had found a way in—a way to distinguish between a brain that was understanding speech and one that was merely experiencing it. Could this be the answer? The key to unlocking the conscious mind? We needed another patient to answer that question.

  In June 2003, Kevin, a fifty-three-year-old bus driver from Cambridge, collapsed with a severe headache and quickly became drowsy. The next day he was unresponsive, paralyzed down one side with strange, uncontrollable eye movements. After he was admitted to Addenbrooke’s, an MRI scan revealed that he had experienced a massive stroke in his brain stem and thalamus—the ultimate “double whammy” for consciousness.

  As we’ve seen, many of the brain’s most essential functions, including sleeping and waking cycles, heart rate, breathing, and consciousness, depend on the brain stem. The brain stem also sends a multitude of sensory signals about hearing, taste, and the sense of touch and pain to the thalamus. The thalamus is a central relay station, or a hub, connecting multiple brain areas in an incredibly complicated network of communicating neurons. The relationship between the brain stem and the thalamus is crucial for holding it all together, maintaining consciousness, and keeping us alive. It’s the be-all and end-all.

  After his admission to Addenbrooke’s, Kevin’s level of wakefulness fluctuated, but then stabilized into deep unresponsiveness. Three weeks of follow-up assessments revealed no change in his condition and he was declared vegetative. Four months after he collapsed, in October 2003, his condition was considered stable enough for us to scan him, and we decided to give the new test Ingrid and her colleagues had developed a go. We’d scan Kevin as we played him the recorded sentences submerged in static and try to figure out whether he could understand them. It seemed like a long shot but worth a try.

  As Kevin’s scan began, I wondered if, after Kate and Debbie, we could get lucky a third time. Amazingly, we did! We saw a strong response in Kevin’s brain areas specifically devoted to processing speech sounds. This was exciting but not new; it was almost exactly the same thing we’d seen in Debbie’s brain when we’d played her single words, with signal-correlated noise for comparison. But it did tell us that Kevin, like Debbie before him, was still processing speech as he had done before his injury.

  In Debbie’s case, that’s where the case had run cold. We could ask no more because we had only tested her with speech and nonspeech sounds, nothing in between. The question of whether her brain could understand speech had therefore remained unresolved. With Kevin we had more. We carefully compared what happened in his brain when we played him sentences that were easy to understand with ones that could only be understood with a bit of extra effort, and with sentences that were difficult to decipher.

  Incredibly, this revealed two sparks of brain activity in the upper and middle ridges of the left temporal lobe of Kevin’s brain. These were the same parts of the brain that were activated when healthy participants had to try that little bit harder to make sense of the sentences submerged in static. Put simply, language comprehension is strongly related to brain activity in the left temporal lobe in healthy participants. In Kevin, supposedly in a vegetative state for four months, activity in this same part of the brain changed as we made a series of sentences increasingly incomprehensible. Surely this was key evidence that Kevin’s brain wasn’t just hearing speech—his brain understood it!

  Nine months after we first scanned Kevin nothing had changed. He was still in a vegetative state, still entirely physically nonresponsive, and still in the hospital. We decided to rescan him. The results were identical. His brain lit up when we played him the same sentences as before; the activity was stronger when those sentences were submerged in static that made them more difficult to understand. The areas of his brain that lit up with each scan were almost identical to those that we had seen nine months earlier. We had replicated our findings. There could be little doubt that Kevin’s brain was processing meaning.

  While it was satisfying to replicate our study, it was also frustrating. What I really wanted to know was what it was like to be Kevin, and whether we could do anything to alleviate any suffering that he might be experiencing. Did he feel the same raging thirst that Kate had felt? Had he tried to end his life by holding his breath? Was he listening to every conversation, or had he left this world and detached himself from the nightmare that his life had become? Was he aware that we had scanned him? Did he know that we had tried to make contact? Did he even care?

  These questions were tantalizing, but I knew that to answer them we had to remain focused, proceed step by step, take each piece of scientific data, scrutinize it, then use it to build up a picture of what was going on in Kevin’s world. If, indeed, he had a world at all.

  In both Kevin’s and Debbie’s cases, we were still trying to understand the ways in which language and consciousness were related. We’d moved forward, but many of the thorny old questions about consciousness persisted. Kevin’s brain could understand the meaning of sentences. Did it mean that when he heard a sentence such as “The man drove to work in his new car,” Kevin experienced the event in his mind’s eye, a fully fleshed-out stream of imagery that he could reflect on and even embellish? Or was his response at a lower, more automatic level; not so much an experience that could be reflected upon, but a simpler association between words and their meanings such that the sentence conjured up an image of a man and a car but little else? Man, work, and car are all common nouns that could register because of their familiarity in the machinery of the brain, yet they could have been for Kevin (and others like him) devoid of the detail or imagery that is part and parcel of our fully conscious experiences.