Confocal image of "Brainbow" mouse cerebral cortex.
In Brainbow mice, neurons randomly choose combinations of red, yellow and cyan fluorescent proteins, so that they each glow a particular color. This provides a way to distinguish neighboring neurons and visualize brain circuits. Honorable Mention, 2007 Olympus BioScapes Digital Imaging Competition.
For additional details see: Livet J, Weissman TA, Kang H, Draft RW, Lu J, Bennis RA, Sanes JR, Lichtman JW.
Nature. 2007 Nov 1;450(7166):56-62.