To summarize, we have demonstrated that iPSCs can be derived from EBV-immortalized B-lymphocytes and that these iPSCs can be differentiated into DG-like neurons. We reproduced the reported endophenotype of hyperexcitability in DG neurons from a new cohort of BD patients and cells. We showed that BD neurons originating from LR and NR patients create two sub-populations of cells that are so intrinsically different from each other that it is possible to predict the response of a new patient to Li based on electrophysiological recordings alone. The large fast AHP that all BD neurons share suggests that it is a key to their repetitive spiking abilities and their hyperexcitability, similar to reports on other types of neurons in which a large fast AHP contributes to fast spiking abilities, such as the fast spiking interneurons.
