Monday, June 04, 2007
Random Walks: Tunnel Vision
James Cameron's 1997 blockbuster movie Titanic broke box office records and garnered bushels of awards; it remains one of the top-grossing films of all times. A large part of its appeal lay in the central (fictional) story of the doomed young lovers, London socialite Rose DeWitt Decatur (Kate Winslet) and impoverished American artist Jack Dawson (Leonardo DiCaprio), who ultimately sacrifices his own life to save hers. A good tragic love story is a time-tested recipe for cinematic success.
But even people whose heartstrings remained untugged by the tearjerker tale couldn't help but be entranced at the spectacle of the great Titanic brought to life on the big screen, and the lavish re-enactment of its tragic sinking makes for stellar cinema. There's just something about the Titanic that resonates with us on a deep, subconscious level, and it is that element that ultimately raises Cameron's film above mere Hollywood bathos.
It's tough to put one's finger precisely on just what that "something" is, but sci-fi author Connie Willis managed to do just that in her 2001 novel, Passage, which I recently re-read for the umpteenth time while recovering from a virus. I've been a Willis fan for years, ever since I read her short stories, "At the Rialto," and "Even the Queen" (included in the collection Imaginary Things). She has the skeptical mind of a scientist -- her husband is a physicist, which probably helps -- and the soul of poet, mixing science fact, science fiction, literary allusion, and metaphor with memorable characters and terrific story-telling. Her broad popular appeal is evidenced by her winning nine Hugo Awards and six Nebula Awards (thus far), making her "one of the most honored sci-fi writers of the 1980s and 1990s."
Willis has tackled time travel, chaos theory, and the sociology of fads (Doomsday Book, To Say Nothing of the Dog, Bellwether), but in Passage, she immerses herself in what is for many the Ultimate Question: is there life after death, a part of our consciousness -- a soul, if you will -- that continues even after the body dies? And to explore her theme, she delineates the science of Near-Death Experiences (NDEs): the proverbial light at the end of the tunnel, at least if the estimated 7 million people who claim to have experienced an NDE are to be believed. Written accounts of NDEs date back some two thousand years,and hail from all over the world. There's even a research foundation devoted to the study of NDEs.
The man responsible for coining the term "near-death experience" is Raymond Moody, an MD who has written several books on the afterlife based on patient testimonials, who believes NDEs are evidence of a soul (consciousness that exists separately from the brain), and evidence of the existence of an afterlife. He's even boiled the typical NDE down to a few key features. First, there's a strange kind of noise, alternately described as a ringing or a buzzing. There is a sense of blissful peace, and often an out-of-body experience (feeling as if one is floating above one's body and observing it from that vantage point). There's that light at the end of the tunnel, being met by loved ones, angels, or other religious figures, and a kind of "life review" -- seeing one's life flash before one's eyes. But as the Skeptic's Dictionary helpfully points out, Moody's books ignore the fact that as many as 15% of NDEs are outright hellish experiences.
It's not all mystical New Age spiritualism, or even overt religiosity. There have been some solid scientific studies of what happens to the brain during such events, most notably a 2001 Dutch study published in the prestigious British medical journal, The Lancet. The researchers examined 344 patients who were resuscitated after suffering cardiac arrest, and interviewed them within a week afterwards about what -- if anything -- they remembered. The results were a bit startling: about 18% reported being able to recall some portion of what happened when they were clinically dead, and between 8 and 12 percent said they experienced some form of an NDE.
Neurochemistry offers some convincing alternative explanations, namely, that NDEs aren't evidence of an afterlife, but illusions created by a dying (oxygen deprived) brain. Cardiac arrest and the anesthesias used in ERs are capable of triggering NDE-like brain states. The Dutch researchers found that "similar experiences can be induced through electrical stimulation of the temporal lobe," for instance, as can neurochemicals such as endorphins and serotonin, and hallucinogenic drugs like LSD and mescaline. Last October, an article in New Scientist described a new theory by University of Kentucky neurophysiologist Kevin Nelson attributing NDEs to a kind of "REM intrusion" : "Elements of NDE bear uncanny similarity to the REM state," he told the magazine. He describes REM intrusion as "a glitch in the brain's circuitry that, in times of extreme stress, may flip it into a mixed state of awareness where is is both in REM sleep and partially awake at the same time." Something similar might be happening with NDEs, he reasons, although the jury is still out on that particular hypothesis.
Karl Jansen has managed to induce NDEs with ketamine, a hallucenogenic related to PCP, but far less destructive; it's an anesthetic that works not just by dulling pain, but by creating a dissociative state. According to Jansen, the conditions that give rise to NDEs -- low oxygen, low blood flow, low blood sugar, and so forth -- can kill brain cells, and the brain often responds by triggering a flood of chemicals very similar to ketamine to protect those cells, which would produce "out of body" sensations and possibly even hallucinations. Jansen claims his approach can reproduce all the main elements Moody attributes to NDEs: the dark tunnel with a light at the end, out of body experiences, strange noises, communing with god, and so on.
Why do so many people see a light at the end of the tunnel? Susan Blackmore, a psychology professor at the University of the West of England in Bristol, thinks she might have an explanation: neural noise. During cardiac arrest, in the throes of death, the brain is deprived of oxygen, causing brain cells to fire rapidly and quite randomly in the visual cortex. There are lots of cells firing in the middle, and fewer towards the outer edge, producing white light in the center fading into dark at the outer edges. That feeling of peace and well-being might be due to the fact that the brain is pumping out endorphins in response to pain, which can produce a dream-like state of euphoria. That same cerebral anoxia might also cause the strange buzzing or ringing sound people claim to hear when they enter an NDE.
Willis takes that tiny bit of factual thread and spins it into a complex scientific mystery, skewering cheap spiritualism in the bargain. She got the idea for the book when a friend insisted she read a book on NDEs, insisting she would find it inspiring. Instead, Willis loathed it. In fact, it made her angry: "I thought it was not only pseudoscience, but absolutely wicked in the way it preyed on people's hopes and fears of death, telling them comforting fictions." She channeled that anger into the novel, creating the character of Dr. Maurice Mandrake, a physician who has abandoned all pretense of scientific objectivity, prompting his "witnesses" to say what he expects to hear -- a strategy that has made him a best-selling author of just the sort of book that triggered Willis' creative rage. (The savvy reader will note some striking likenesses to Moody.)
Mandrake's foil in the novel is the main protagonist, Joanna Lander, also a doctor studying NDEs, but her approach is far more rational, firmly grounded in the scientific method -- which puts her at odds with Mandrake and his minions. She finds an ally (and potential love interest) in neuroscientist Richard Wright, who has contrived a way to induce NDEs using a psychoactive drug called dithetamine. (I guess one could say he's the fictional counterpart to Jansen.) His theory is that the NDE is a survival mechanism, part of a series of strategies the brain employs whenever the body is seriously injured. The NDE is a side effect of neurochamical events.
While NDEs seem to have some striking similarities in the various recorded accounts, what specific form the NDE will take depends on the individual, and for Willis, this provides an opportunity for a clever twist. Recall the now-famous final scene in Cameron's Titanic, when the elderly Rose, having lived a long, full life, dies quietly in her sleep. The camera follows her "soul's" journey out of her body, towards a white light, then down into the ocean depths until she reaches the present-day wreck. As the camera moves into the main dining hall, we see the shipwreck morph back into its former unsunken glory, and all those who perished are on hand to welcome Rose back to the fold. Waiting at the top of the grand staircase is Jack himself, who takes Rose's hand, her youth restored, and the lovers are reunited in eternity. (Cue violins and a thousand sobbing fans, followed by that overblown -- and overplayed -- Celine Dion ballad.)
But what if Rose hadn't willingly gone into the light? Then she may have popped back to her reality as an elderly woman in the middle of the ocean, on a complimentary junket to re-visit the sunken ship because she alone might know the secret of the fabulous lost diamond necklace. And her "vision" would have classified as a classic NDE. Joanna would definitely have wanted to interview her. Not only would Rose have made an excellent witness, but the two share a common NDE framework. When Joanna consents to let Richard induce NDEs in herself as a subject, she also finds herself on the Titanic -- the very day of its sinking.
Of course, it isn't really the Titanic: she knows that, even though the experience feels uncannily real, nothing like a typical dream state. But Joanna is convinced there's a reason her subconscious has picked this particular framework in which to place her NDE. The Titanic is the perfect metaphor for what is happening as the brain strives to make sense of things even as it is dying (or pseudo-dying, in the case of induced NDEs). The body is a sinking ship, the chemical signals and electrical impulses are SOS messages trying to find some form of rescue, some way of jump-starting the body before brain death sets in, within four to six minutes after the onset of oxygen deprivation. The metaphor of the Titanic, says Joanna's former English teacher, is "the very mirror image of death."
Willis knows a little something about death, having lost her mother quite suddenly when she was 12, an experience she has described as "a knife that cut across my life and chopped it in two. Everything changed." But she didn't take refuge in the popular Hallmark sentiments that often pass for profundity in this country. ["[O]ur American culture is especially in denial about death," she said in a 2003 interview, and while writing Passage, "I wanted to make sure some reader who had just had somebody die... would say, 'Thank you for telling the truth and trying to help me understand this whole process.'"
And what a brutal truth it is. The novel ends by taking us right into the dying brain of one of the characters, quite conscious and very aware of what these visions represent: synapses firing randomly, memories falling away, even language being lost, before the visual cortex shuts down completely. The depiction is unflinching, and all the more powerful because it never resorts to easy platitudes. It's not an easy book to read; it's decidedly unsettling, yet I return to it again and again. Maybe it's because Willis stops short of letting everything go dark; in the end, she acknowledges that perhaps some things cannot -- and need not -- be known. By leaving things open-ended, Passage reassures us that it's okay for this to remain unknown. Our only job, as human beings, is to make the life journey as rich and meaningful as possible -- in whatever way we choose to do so.
It's safe to say that a vast majority of the world's population professes to believe in some form of life after death, even if the form it takes differs from culture to culture; it's far more comforting to them. No doubt many of those resist any attempt by scientists to explain their experiences from a rational perspective. Like Maurice Mandrake and his fawning acolytes in Willis' novel, they want their mystical/spiritual trappings, and consider alternative scientific explanations to be a kind of cheapening of such beliefs and experiences.
Even before I became a science writer, I never understood that attitude. How much more magical and wondrous to discover that there is a rational reason why we experience such things. "[P]eople are trying to validate their experience by making these paranormal claims, but you don't need to do that," Blackmore told ABC News when the Lancet study was published in 2002. "They're valid experiences in themselves, only they're happening in the brain and not in the world out there."
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