In this study, we present functional measurements of DG granule-cell-like neurons differentiated from iPSCs derived from EBV-immortalized lymphocytes of BD patients. We find that the endophenotype of hyperexcitability is shared by BD DG neurons, in support of our previous findings.42 We further show that BD neurons can be subdivided into at least two populations of neurons, where neurons within a sub-population share similar features but these sub-populations are very different functionally from each other. Using features extracted from electrophysiological measurements from these two sub-populations, can predict the responsiveness of a new patient to Li with a success rate of over 92%. The cellular phenotype shared by these sub-populations is hyperexcitability, and the electrophysiological feature that they share is a large fast AHP, a feature known to assist fast spiking interneurons with their fast spiking abilities.
