Understanding how the brain works to produce behaviour is one of biology’s greatest challenges, and the sheer complexity and number of cells in vertebrate brains makes it difficult to get a close look. While most studies rely on painstakingly reconstructing 3D images from thin sections, a new technique allowing much thicker samples, even whole brains, to be observed in detail has recently been developed. Named CLARITY, the method uses a detergent to dissolve the cells’ fatty membranes, effectively making brain tissue transparent under the microscope. Researchers can then see deep inside the brain, identify particular cell types and track their connections. In the video, CLARITY has been used to image a mouse hippocampus, and different cell types have been labelled with fluorescent proteins. The technique has also been applied to human samples, opening up new possibilities for exploring both neural networks in healthy brains and the causes of neuronal diseases.
Written by Emmanuelle Briolat
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