Visual Neurons (IMAGE) Howard Hughes Medical Institute Caption Shown here in different colors are two of the many neurons that provide visual signals to the compass in the fly brain. Each of these neurons spans the entire compass, producing a set of concentric circles. Credit Isabel D'Alessandro Usage Restrictions Must use credit. License Licensed content 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.