Neurons Used for Drug Testing (IMAGE) Cell Press Caption Neurons generated from neural stem cells. These are the cells, which were used for drug testing. They show the typical neuronal morphology with long processes. Again, this is an immunofluorescence analysis, this time with antibodies to the neuronal proteins beta-III-tubulin (green) and tau (red); many processes contain both proteins and thus appear yellow. Credit <i>Stem Cell Reports</i>, Mertens et al. Usage Restrictions Credit Required 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.