(IMAGE) Max-Planck-Gesellschaft Caption This projection neuron forwards carbon dioxide information to the region in the fly's brain where the animals can gauge internal and external signals. Credit MPI of Neurobiology / Purayil & Kadow Usage Restrictions None 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.