nor does it produce any major changes in the passive membrane properties of D398 and N398 human neurons (Fig. 2I). However, while DA neurons with different CHRNA5 gene variants have similar intrinsic excitabilities, the N398 variants also have a slightly higher frequency of spontaneous APs (Fig. 2F), which could be due to differences in synaptic network activity. Since the DA neuronal cultures also form synapses as revealed by synapsin puncta (Fig. 2J,K), we turned to measurements of postsynaptic activity.
