Nerves Innervate Color-Changing Iridophores in Squid Skin (video) Marine Biological Laboratory Share Print E-Mail Loading video... Caption Yellow, red, and brown chromatophores (organs composed of a large pigment cell) surround a single iridophore, which consists of hundreds of iridescence cells. A nerve bundle (not in view of video) is electrically stimulated when the red square appears in upper left corner. Brief electrical pulses initiate action potentials in the nerves which travel to the iridophores and chromatophores. At first the chromatophores respond, but with time, the iridophores also respond. The movie is 4 times normal speed. Credit Wardill, Gonzalez-Bellido, Crook & Hanlon, Proceedings of the Royal Society B: Biological Sciences Usage Restrictions May be used 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.