Reprogramming Brain Cells (IMAGE) University of Pennsylvania School of Medicine Caption These are dopaminergic neurons generated by directly reprogramming astrocytes. Green stain denotes expression of tyrosine hydroxylase, an enzyme required for dopamine synthesis. Credit Russell Addis, PhD, Perelman School of Medicine, University of Pennsylvania 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.