At Memorial Sloan-Kettering, Dr. Philip Gutin and neuroscientist Joy Hirsch have begun applying a decade-old technique -- functional magnetic resonance imaging (fMRI) -- to brain surgery. Unlike conventional MRI, which only shows structure, fMRI detects minute changes in blood flow, so areas of the brain that are active during a particular task -- say, tapping your finger or telling a story -- light up. Dr. Gutin can then pin down the relationship between a tumor and sectors of the brain that shouldn't be touched. (After pre-operative fMRI, Gutin may also map brain function during the actual surgery using electrical stimulation.) "We don't have one language area," explains Hirsch. "We have a network of areas that are bound together in a transient way for the purpose of executing that task." Moreover, some tasks, like object-naming, are accomplished slightly differently in different brains. "Unless you do an individual map for an individual person," Hirsch says, "you just don't know what you might be hurting."

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• Archive: “Cover Story”
• Articles by Erika Kinetz
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