Brainbow is the process by which individual neurons in the brain can be distinguished from neighboring neurons using fluorescent proteins. By randomly expressing different ratios of red, green, and blue derivatives of green fluorescent protein in individual neurons, it is possible to flag each neuron with a distinctive color.
The technique was originally developed in the Spring of 2007 in the Department of Neurobiology at Harvard Medical School, and first published in the November 1, 2007 issue of the journal Nature.
While earlier labeling techniques allowed for the mapping of only a few neurons, this new method allows more than 100 differently mapped neurons to be simultaneously and differentially illuminated in this manner. The resulting images can be quite striking and have won awards in science photography competitions.