The Functional Principle (IMAGE) University of Bonn Caption The rear laryngeal muscles are genetically modified so that they open the air passage when exposed to light. Credit Courtesy of Dr. Tobias Bruegmann Usage Restrictions This photo may be used with the press release. 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.