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 […]Continue reading
Why you should listen
How many neurons make a human brain? For years, the answer has been (give or take) 100 billion. But neuroscientist Suzana Herculano-Houzel decided to count them herself. Her research approach involved dissolving four human brains (donated to science) into a homogeneous mixture -- in her lab at the Institute of Biomedical Sciences in Rio de Janeiro, they call it "brain soup." She then took a sample of the mix, counted the number of cell nuclei belonging to neurons, and scaled that up. Result: the human brain has about 86 billion neurons, 14 billion fewer than assumed -- but intriguingly, far more than other animals, relative to brain size.
She suggests that it was the invention of cooking by our ancestors -- which makes food yield much more metabolic energy -- that allowed humans to develop the largest primate brain. She's now working on elephant and whale brains to test her hypothesis.
"What others say"
Suzana Herculano-Houzel’s TED talks
Suzana Herculano-Houzel on the TED Blog
This session asks us to pay closer attention to what nature has to tell us — both about itself and about the world around us. We’ll investigate a variety of sources — from the soundscapes of ecosystems to the neurons of cockroaches to the extraordinary sex lives of animals. Here are the speakers who appeared […]Continue reading