Preserved for years in hospitals and labs, human brain samples may contain valuable clues to how neurons connect to each other, or go awry in disease. Yet their secrets are often hidden among cloudy fatty molecules. This thumbnail-sized piece of human cerebellum has been bathing in a newly-developed 'clearing' solution – a cocktail of chemicals that sluices away fats and other obstructive particles. Similar solutions have already turned rodent brains transparent, but scientists have only just cracked the right mixture for human brains. Pictured under a microscope, a coloured stain highlights neurofilaments – stringy proteins found in the cytoplasm of neurons, each colour-coded by its depth in the tissue. The technique can be used with archived tissue samples around the world, but also with brains donated to medical science – so researchers can compare diseased and healthy tissue for clues to illnesses and insight into brain injuries.
Written by John Ankers
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