Originally posted on TED Blog:
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. This made a homogenous mixture that allowed her to count the neurons in a sample. As it turns out, the human brain really has 86 billion neurons.
Why does this difference of 14 billion neurons matter? It answers a vital question: What makes the human brain different, allowing us to get together for thought-fests like TEDGlobal 2013, while other animals don’t?
For a long time, scientists thought that all mammal brains were made of the same…
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