Neurons derived from human pluripotent stem cells (hPSCs) and primary rodent neurons both are excellent resources for disease modeling and drug screening. Human PSCs derived neural stem cells (NSCs) can be expanded in culture and further differentiated into mature neurons for various applications, however, these often contain mixed population of both differentiated neurons and undifferentiated NSCs. Due to the continuing proliferation of undifferentiated NSCs, very high cell densities and cell aggregation are usually observed during the differentiation of hPSC-derived NSCs which increase over time, posing challenges for long-term maintenance and downstream analysis. Primary rodent neuronal cultures, while highly physiologically relevant, are often challenged by glial cell overgrowth, which may exacerbate assay and analysis issues. Here we demonstrate the use of CultureOne(tm) - a new supplement which can reduce the proliferation of undifferentiated NSCs without negatively impacting the rate or extent of differentiation for hPSC-derived NSCs. Further, we will demonstrate the ability to "tune" the glial cell population in primary rodent neuronal cultures. The overall effect in both instances increases the relevant population of neurons in culture. Experimental data presented in this webinar will illustrate the functionality, morphology, and maturity of these neuronal cultures.