By combining physics, neuroscience, and optics, Mark Schnitzer intends to directly observe single neurons deep below the surface of the living mammalian brian; it would be a scientific first. While working at Lucent Technologies’ Bell Labs, Schnizer crafter an incredibly small endoscope- a fiber-optic viewing device with lenses as small as 350 micrometers across. The scope illuminates brain cells that have been labeled with a fluorescent dye; detectors in the device pick up the fluorescence and software constructs images of the cells. The device could allow neuroscientists to see how brain cells function, grow, and communicate across time synaptic gaps. Already, researchers are preparing to use Schnizer’s tool to study how animals store long-term memories. Because it is so small, the endoscope could also be fed deep into the brain, inflicting minimal harm on surrounding neurons. Human trials are years away, but Schnitzer says eventually his tool may help doctors detect brain cancers and blood clots without biopsy. Now an assistant professor in Stanford University’s departments of applied physics and biological sciences, Schnitzer continues to apply his tools to brain research.