CLARITY is a method of making brain tissue transparent using acrylamide-based hydrogels built from within, and linked to, the tissue, and as defined in the initial paper, represents "transformation of intact biological tissue into a hybrid form in which specific components are replaced with exogenous elements that provide new accessibility or functionality". When accompanied with antibody or gene-based labeling, CLARITY enables highly detailed pictures of the protein and nucleic acid structure of organs, especially the brain. It was developed by Karl Deisseroth and his colleagues at the Stanford University School of Medicine.Subsequent published papers using the CLARITY method of building acrylamide-based tissue-gel hybrids within tissue for improved optical and molecular access, have included studies on Alzheimer's Disease human brains (Ando et al., Acta Neuropathol 128:457–9, 2014), mouse spinal cords (Zhang et al., Proceedings of the National Academy of Sciences USA 111: E1149-58, 2014), multiple sclerosis animal models (Spence et al. Neuroimage, http://dx.doi.org/10.1016/ j.neuroimage.2014.07.017, 2014), and advanced microscopy methods including CLARITY-enhanced light sheet microscopy or COLM (Tomer et al., Nature Protocols 9:1682–97, 2014).