Why do teenagers take so many risks, and how does schizophrenia work in the brain? These two questions may share a common answer: they are possibly due to a type of brain cell called "in-between neurons." 

The brain still holds many mysteries; one of these is the in-between neurons. They are neither grey matter, the information processing center of the brain, nor are they white matter, where neurons are surrounded by a myelin sheath, a fatty layer needed for speedy signal transmissions.

In-between neurons are technically referred to as superficial white matter (SWM). They are special because they only have a thin layer of myelin, but not enough to make them visible under a microscope. Strangely enough, even though SWM only has a thin layer of fat, it is one of the last parts of the brain to fully develop.

Until now, scientists have been unable to view these lightweight neurons through a microscope. However, a European research group has now devised a simple solution to see them up close. They used ultra-high resolution brain imaging and found that iron was a good indicator of where SWM is located in the brain. They then developed a mathematical model to map the location of iron in SWM throughout the human brain, enabling them to non-invasively "see" these in-between neurons. 

Being able to get a more detailed picture of these SWM neurons will allow for greater understanding of the brain. Areas of the brain with SWM are important to the normal functioning of the brain and also in conditions such as schizophrenia and Alzheimer's. Finding out more about SWM's role in these conditions could help improve symptoms in those who have them.