What lies between grey and white in the brain

Traditionally, neuroscience regards the brain as being made up of two basic tissue types. Billions of neurons make up the grey matter, forming a thin layer on the brain’s surface. These neuronal cells are interlinked in a mindboggling network by hundreds of millions of white matter connections, running in bundles, deeper in the brain. Until very recently, not much was known about the interface between the white and grey matter – the so-called superficial white matter – because methods were lacking to study it in living human brains. Yet, previous investigations had suggested the region to be implicated in devastating conditions such as Alzheimer’s disease and autism. Now a multidisciplinary team led by Nikolaus Weiskopf from the Max Planck Institute for Human Cognitive and Brain Sciences has succeeded in making the superficial white matter visible in the living human brain.