How to image the brain without slicing

An innovative microscope allows scientists to peek at the brain’s long-range neuronal circuitry without having to reconstruct it from individual brain slices. The technique removes lipids to make the tissue transparent before it is embedded in a material that expands when water is added. At the heart of the method is a type of lens that is usually used to identify pixel-sized defects in flat-panel displays. The prototype microscope’s resolution is comparable to that of high-resolution imaging using standard confocal microscopy. It’s also fast: it can image an entire mouse brain in less than a day.