SUMMARY AND RELEVANCE: The purpose of the Core 2 is to assess the extent to which iPSC-derived neurons differentiated down a particular line Core 1 have achieved the expected mature phenotype. This is necessary so as to assure potential users of the properties of the neurons that are produced. The properties of such cells are extremely specific and the purpose of this core will be to examine how closely neurons produced from iPSC lines correspond to the known properties of the different neuronal types prior to handing them off to potential users for their individual projects. Core 2 will also be able to help clients answer specific questions about the status of different cellular characteristics in cells derived from different patient populations.