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Consciousness Raising: Can the darkness of anesthesia shed light on the mind?

By Phungushead, Jan 9, 2014 | |
  1. Phungushead
    View attachment 36650 If you want to commingle the arts with the science of anesthesiology without scaring away the audience for either, telling a zombie tale never hurts. That’s what George A. Mashour, MD, PhD, did when he co-authored a 2008 article in the journal Consciousness and Cognition that could have passed peer review in a Poe anthology. The paper argued that a “philosophical zombie”—an unconscious creature that behaves and responds like a human—is “naturally improbable.” But an “inverse zombie”—a creature that appears to be unconscious but in fact is not—is possible. Indeed, such a state fairly describes a patient experiencing awareness during anesthesia.

    Dr. Mashour’s blending of sci-fi horror with anesthesiology produced “an absolutely brilliant article,” said Max B. Kelz, MD PhD, professor of anesthesiology at the University of Pennsylvania, in Philadelphia. Dr. Mashour “is extremely well-read and able to see connections between ideas that span diverse fields.”

    Dr. Mashour, professor of anesthesiology at the University of Michigan, in Ann Arbor, is interested in the hard science behind his field. His most recent study, for instance, found that patients who previously experienced intraoperative awareness with recall were five times more likely to do so again than were patients who had never had the experience.

    From Aladdin’s Lamp to Areas Under the Curve

    View attachment 36648 Much of his work uses electroencephalograms (EEGs) to parse the effects of different anesthetic drugs on the brain. That’s not terribly unusual. But what sets Dr. Mashour apart from his peers is his desire to have an intellectual, liberal arts conversation about anesthesiology—one that would attract and entertain folks at a dinner party who had never laid eyes on a medical textbook. His manuscripts are just as liable to contain references to Aladdin’s lamp and psychedelic mushrooms as they are to P values and confidence intervals.

    Dr. Mashour is particularly interested in understanding consciousness. “It’s really a fundamental question,” he said. “We wake up in the morning. We open our eyes and this world shows up for us. The question is how does that happen? What is the mechanism in the human brain that allows us to generate experience? How is it that the anesthetics we use are able to turn that off in a rapidly reversible way?”

    Although anesthesia has been around the better part of two centuries, the scientific study of consciousness is relatively young. Dr. Mashour counts himself among the early adopters. An acceptable scientific definition of “consciousness” remains ephemeral to him. “Philosophers have been asking this question for millennia,” he said. “Everybody knows what it is. You know what it’s like to see a sunset or hear a symphony. But how do we put this subjective process into objective terms? And if I use a term, how can I be sure that I mean the same thing you do? How do I know what you’re calling ‘green’ isn’t something different? This problem becomes even more difficult when considering a scientific or quantitative description of a subjective process.”

    Dr. Mashour received what he called a “classical liberal arts” education, but became interested in the conscious mind when he read DNA pioneer Francis Crick’s articles on the subject. He had just started at Georgetown University School of Medicine (he completed his MD and PhD in 2001), and it “opened my eyes.” He became further interested when he began his residency at Harvard.

    “For most of the 20th century, consciousness—even in the field of psychology—was not considered a valid topic of interest,” he said. A multidisciplinary approach to it wasn’t taken seriously until the 1990s. Even today, anesthesiologists “have a very small representation in this field.”

    Jamie Sleigh, MD, an anesthesiologist at the University of Auckland, in New Zealand, who has followed Dr. Mashour’s work, said the study of consciousness had been frowned upon for too long. “It was ridiculous to ignore such a fundamental phenomenon,” Dr. Sleigh said. “It is driven by fear that it would expose the limitations of reductionist science—which is probably true.”

    Dr. Mashour’s contribution is to examine anesthesia’s role in consciousness. “Is that the same brain that’s coming out of the general anesthetic, or does that anesthetic have effects that cause persistent cognitive dysfunction?” he said. “Is it a patient factor? Is it the anesthetic? Is it the surgery, stress, inflammation or some combination of these factors? Whether all the pieces are being put back together is a question for the field.”

    Dr. Mashour’s studies on consciousness provide a bridge between anesthesiology and the outside world because he “links the latest EEG/imaging analysis methods with the clinical and philosophical consequences,” Dr. Sleigh said.

    “There are not many clinicians, let alone full-time scientists, who could blend seemingly divergent fields as harmoniously as George has,” Dr. Kelz said. “Most amazingly, George’s science isn’t restricted to the lofty towers of academic institutions. Rather, I’m confident that George’s work has already had—and will continue to have—true translational power. His work has adapted and extended previous basic science discoveries—such as the asymmetric directional changes in the EEG that herald the loss and return of consciousness—that may improve patient safety by reducing the incidence of awareness under anesthesia.”

    Getting Metaphysical

    Dr. Mashour made a splash in the general news cycle last August with the publication of a study on which he was senior author describing electrical activity in the brains of dying rats (Proc Natl Acad Sci USA Aug 12, 2013; doi: 10.1073/pnas.1308285110). The researchers found, contrary to commonly accepted belief, that there was a “transient surge” in meaningful neurophysiologic activity in the 30 seconds after a heart attack that exceeded activity during the waking state. A Washington Post article on the study attracted 1,300 comments and much buzz about whether people who have had near-death experiences may have experienced heaven, as some have claimed—including a neurosurgeon, Eben Alexander, MD, who wrote about his experience in the book, “Proof of Heaven.”

    “It’s a topic that transcends science and moves into questions about religion, the afterlife, the existence of God,” Dr. Mashour said. But he hastened to add: “We weren’t making a claim that animals were having a near-death experience.” Instead, the study showed that after a heart attack, “there are some features associated with conscious processing that seem to come back with a vengeance.”

    His lab at Michigan is as varied as his writings. It includes biomedical engineers, physicists, neuroscientists and even a philosopher. “I like a multidisciplinary approach,” he said, even if things can get chaotic. “I do like people who are able to take a broad look at the problem.”

    JANUARY 2014

    John Dillon
    Anesthesiology News


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