http://www.newscientisttech.com/article/dn11518-how-to-make-a-brain-transparent.html

The entire neural network of a mouse’s brain has been seen in 3D for the first time, using a new technique that renders tissues transparent.

The method – dubbed “ultramicroscopy” – has also enabled researchers to visualise the detailed anatomy of a mouse embryo in 3D. It will provide new insight into how organs such as the brain develop, the researchers say.

Until now, it has been impossible to visualise entire neuronal networks in an intact brain – techniques such as computer tomography (CT scans) or magnetic resonance imaging (MRI) do not have the resolution to reveal detail at the cellular level. Slicing the brain for microscopic imaging is possible, but creating a 3D image from many slices is laborious and prone to distortion problems.

Hans-Ulrich Dodt, now at Vienna University of Technology in Austria, and colleagues, have combined two old techniques to make a new tool that allows researchers to look at an entire brain on a microscopic level.