Finally, future studies will be required to address the full in vivo potential of human in vitro derived cortical interneurons for applications in regenerative medicine. Our current study illustrates the remarkable migratory potential of the hESC-derived cortical interneurons upon transplantation into the neonatal mouse cortex. Transplantation studies into several adult CNS models of disease will be of particular interest given the potential use of cortical interneuron grafts in modulating pathological seizure activity (Baraban et al., 2009), treating aspects of Parkinson’s disease (Martinez-Cerdeno et al., 2010) and inducing learning and plasticity within the postnatal brain (Southwell et al., 2010). One specific challenge for such transplantation studies is the protracted maturation of grafted hPSC-derived cortical interneuron precursors in vivo. Preliminary longer-term transplantation studies into the adult mouse cortex confirm their continued slow maturation rate with NKX2.1+ putative interneuron precursors retaining immature growth cones and showing limited integration at 3 months post grafting (data not shown). Those data are in contrast to our in vitro co-culture work where rapid functional integration and phenotypic maturation was readily achieved. In sum, this study provides a
