Neuroscientists have made a discovery that turns 160 years of neuroanatomy on its head. Myelin, the electrical insulating material long known to be essential for the fast transmission of impulses along the axons of nerve cells, is not as ubiquitous as thought, according to a new work. "The fact that it is the most evolved neurons, the ones that have expanded dramatically in humans, suggests that what we're seeing might be the "future." As neuronal diversity increases and the brain needs to process more and more complex information, neurons change the way they use myelin to "achieve" more," says the main researcher.