Can’t say as I really understand what this is showing, but it’s still pretty amazing. The project was funded by Paul Allen of Microsoft fame through the Allen Institute.

The Allen Brain Atlas (ABA) is an interactive, genome-wide image database of gene expression in the mouse brain. A combination of RNA in situ hybridization data, detailed Reference Atlases and informatics analysis tools are integrated to provide a searchable digital atlas of gene expression. Together, these resources present a comprehensive online platform for exploration of the brain at the cellular and molecular level.

Brain Explorer is a desktop software application for viewing Allen Brain Atlas (ABA) gene expression data in the framework of the Allen Reference Atlas (ARA) in 3D. Using Brain Explorer, you can:
• View a fully interactive version of the ARA in 3D
• View gene expression summary statistics in 3D at 100μm3 resolution
• View expression data from multiple genes superimposed on each other in 3D
• Navigate the high-resolution 2D ISH images from the ABA using the 3D model
• Link to associated gene metadata on the ABA website
The 3D data shown in Brain Explorer is generated from the same process employed in the search algorithms on the ABA web site (http://www.brain-map.org). Image registration enables the mapping of ISH data into the common coordinate framework of the reference atlas. Expression can be presented in 3D as a result of this mapping. In Brain Explorer, expression data is presented at a 100μm3 resolution level.