This micrograph of a zebra fish brain was a finalist in Nikon´s annual Small World Competition, a contest among professionals and amateurs in the field of light microscopy, the craft of imaging small items with visible light. Here, the fish´s embryonic brain glows because of fluorescent molecules that bind to specific proteins in the tissue. Long, message-carrying axons of neurons shine blue, while a specific form of a protein called tuberin radiates red.
Scientists use zebra fish to study vertebrate development because they are often cheaper and easier to work with than mice or chicks. The researcher who shot this image, biologist Michael Hendricks of the Temasek Life Sciences Laboratory in Singapore, is investigating tuberin´s role in forming connections between neurons. The study is of particular interest because tuberin plays a role in a genetic disease that causes benign tumors in humans.