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Brain chemistry, demystified

Mind Wide Open Your Brain and the Neuroscience of Everyday Life Steven Johnson Scribner: 276 pp., $25

March 10, 2004|Bernadette Murphy | Special to The Times

Steven JOHNSON is fascinated by brain chemistry, an attraction he traces back to a biofeedback session he participated in some years ago. Hooked up to the machine, he watched as the numbers documented precisely how much he was sweating. "I've never taken a lie detector test, but something about having a stranger ask me questions while keeping a close eye on my sweat glands put me on edge. And so I started making jokes," he writes in "Mind Wide Open," an absorbing narrative charting his journey, as a nonscientist, into the realm of the brain.

Johnson, editor of Feed, an Internet magazine covering technology, science and culture, was on to learning something crucial about himself. As he repeatedly caused a spike in his own adrenaline levels by telling those nervous jokes, he realized that he'd established a simple feedback circuit, compelling his brain to deliver a targeted adrenaline rush every time he made a passing joke. "I thought of all those dreary meetings or sober conversations with friends that I'd interrupted with borderline inappropriate jokes; I thought of how deeply ingrained that impulse was in my day-to-day personality -- and suddenly my attempts at humor seemed more like the cravings of a drug addict than the amusements of a class clown, my brain scrambling to put together a cheap laugh to secure another adrenaline fix."

The experience got him thinking: If we could study the minute-by-minute variations in our brain chemistry, what would we learn about ourselves and our emotions? Could understanding these chemicals help us make sense of our dreams and phobias? "What would you learn about yourself ... [i]f you could see what your brain looked like when it was remembering a long-forgotten childhood experience, or listening to a song, or conceiving a good idea?"

He sets out to answer these questions in "Mind Wide Open" and uses himself as the guinea pig. Exploring how our brains are wired, he looks into the way they move chemicals about and respond to stimuli. Our personal history -- childhood memories or previous trauma, for example -- clearly plays a role in our reaction to the outside world, but chemicals, he tells us, have an equally strong influence. If we're low on serotonin, say, we might feel depressed and have a heightened sensitivity to personal rejection. If oxytocin is flowing, as is common in a nursing mother, we're driven to form deep emotional bonds with those we love. Adrenaline gives us a surge of energy, while endorphins flood the brain with a sense of expansive bliss.

As he explores this subject, Johnson participates in tests to see how his brain is actually working. He undergoes a computer-based assessment of his ability to "read" faces by staring at photographs of people's eyes and naming the correct emotion of the person photographed. One of the human brain's greatest evolutionary achievements, he learns, is its ability to model the mental events occurring in other brains. But we can't think about this as we do it because intellectualizing the process lessens our ability. "[W]hen I just let myself look -- look without thinking," he writes, "the underlying emotions came through with startling clarity."

In "Survival of the Ticklish," a fascinating chapter on humor and laughter as human traits, he finds that most laughter takes place as a kind of community-building -- laughing together with others over nothing particularly funny -- rather than responding to a joke. We're programmed to laugh, not because things are so comical, but because laughter connects us to others. Likewise, tickling a child is preprogrammed: "Children who laugh and roughhouse and tickle with their guardians create powerful bonds of affection ... and those bonds help them survive."

Johnson even undergoes an fMRI scan of his brain at the moment he's composing words for the book to see what will show up. Half hoping that the scan will demonstrate extraordinary language skills in his brain, he's initially surprised by the results. The test shows that when he is focused, there is almost no activity in areas of his brain that aren't related directly to the task at hand; the scan itself is almost blank. But this, he comes to see, is a sign of efficiency, proof of a well-orchestrated brain.

Our brains, he shows us in this intriguing, accessible narrative, are wonderful, complex instruments, marvelous in their multiplicity. "You are part reptile, part mammal, part primate, part homo sapien.

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