Tsuyoshi Yamamoto is steering his way through the brain. Since joining Hitachi’s Advanced Research Laboratory in Hatoyama, Japan, in 1997, he has codeveloped an optical-topography system that measures changes of concentrations of hemoglobin in the brain, providing insight into how neurons process language, images, and movement. Yamamoto’s device, which is easier to use and cheaper than magnetic-resonance imaging (MRI), beams light through the skull and into the cortex, the brain’s outer layer. By charting the intensity of the light reflected back by the cortex, the machine gauges changes in blood cell concentrations- indications of brain activity. The instrument, which looks like a beauty salon dryer, is less motion sensitive than MRI equipment, so rather than lying flat, patients are seated for scans. Now on sale in Japan, the system has received U.S. Food and Drug Administration approval. Patients robbed of muscle control by neurodegenerative disease can communicate via Yamamoto’s gear, which can sense the brain’s “yes” and “no” responses to questions. He hopes his device will further understanding of language processes. “We don’t know so much about the brain,” he says. “I would like to find new functional areas.”