Developing Brain (image) Howard Hughes Medical Institute Share Print E-Mail Caption In a ferret's developing brain, stem cells (green) send long fibers (green threads) throughout the cortex. These fibers shepherd new neurons to the right place -- and ultimately help the cortex form its folded structure. Credit Walsh Lab/HHMI/Boston Children's Hospital Usage Restrictions Must use with credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.