For decades, scientists said that the human brain contains 100 billion neurons. However, when neuroscientist Suzana Herculano-Houzel hunted for the source of this often-quoted number, she couldn't locate one. So she set out to count herself ... by making brain soup.
She brings a vial of brain soup with her onto the TEDGlobal 2013 stage. This substance was made by dissolving donated brains, destroying the cell membranes but leaving the nuclei intact.