He suspects the brain routinely taps into myelin for fuel, just at levels too low to detect—except during extreme events like a marathon. But there’s no need to panic, he says.

Cerebrospinal fluid, or CSF, is a clear, colorless liquid that plays a crucial role in maintaining the health and function of your central nervous system. It cushions the brain and spinal cord ...

The inner structures of the brain are difficult to investigate without surgery. Credit: K H Fung/Science Photo Library. Neuroscientists have observed for the first time how structures deep in the ...