Substantia Nigra (IMAGE) University of Basel Caption These are two cell populations in the substantia nigra that are responsible for different aspects of locomotion. Credit University of Basel, Biozentrum Usage Restrictions With current release only 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.