From Eye to Brain (3 of 3) (image) Salk Institute Caption Photoreceptors in the retina convert visual information into electrical signals and send them to an intermediate layer, which in turn relays signals to the 20 or so distinct types of retinal ganglion cells. Credit Image: Courtesy of Jamie Simon, Salk Institute for Biological Studies. Usage Restrictions News media reproduction to illustrate this story permitted with the proper attribution as provided above. For one time use only. 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.