Rendering brain tissue transparent can help explain degenerative disease

Researchers from Imperial College London and Hong Kong University have developed the method for "clearing" brain tissue as a way of making the task of tracing the complex circuitries of nerve cells within the brain much less arduous.

Traditionally, neurons are mapped by slicing the brain into multiple thin slices and tracking the cells as they pass in and out of many sections, a process that can take weeks. Scanning techniques such as MRI are useful for visualising larger structures, but cannot achieve the three-dimensional resolutions needed to map neurons.

Clearing is a technique that uses chemicals which, when soaked into brain tissue, make opaque tissues transparent, leaving the neurons visible without altering or changing their structure. However, up to now it has only been effective in rodent brain tissue, and there are major differences between the brains of mice and those of humans, including important differences in the chemistry of the tissues and the density of certain substances.