PirB Expression (image) NIH/National Eye Institute Caption PirB (red) is heavily concentrated on the surface of growing nerve cells. Credit Dr. Carla Shatz, Stanford University. Usage Restrictions Please credit Dr. Carla Shatz, Stanford University. 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.