A group at Stanford led by Karl Deisseroth have pioneered a chemical process that leaves brain (and other) tissue intact but optically transparent. The procedure, aptly named CLARITY, exposes internal structure by replacing the opaque lipid layers that surround cells with a transparent shape-preserving hydro-gel. Neurons, glia, genes and other molecules of interest can then be selectively highlighted in this transparent brain by molecular markers. The results are spectacular and reminiscent of swimming among the jellyfish.
This is a
link to Nature which published the article. The accompanying set of video clips is compelling; in one frame, a single nerve projection is traced out among a tangle of other neurons. The technique will provide a boost for the field of connectomics; researchers who would otherwise have to reconstruct neural wiring from small piece-meal sections of brain will be able to view whole-brain connections in one glance.
Update August 10 2013:
A short clip of Karl Deisseroth on CLARITY.
