The research group of Yasutaka UEDA identiied a reagent capable of simultaneous tissue swelling and rendering it transparent. When sheets of brains were analyzed by fluorescence microscopy, a complete atlas of a mouse brain could be displayed as a sort of pointillist painting. Two compounds were used: imidazole (tissue swelling agent) and antipyrine (tissue swelling and refractive index control agent). By combining these reagents with a conventional tissue degreasing agent developed by the same group for whole brain imaging (CUBIC-X”), mouse brains showing very high transparency and swollen about 10 times in volume were created. As one application, mice were administered the NMDA receptor antagonist, MK-801, and activated and inhibited cell groups were analyzed at single cell level. In the dentate gyrus cell layer of the hippocampus, activated and inhibited cells were localized at different sites, and thus functional diversity of the dentate gyrus cell layer could be observed.”

AMED news release, March 3, 2018