in neurons expressing hM3Dq, we were able to estimate a half maximal effective concentration (EC50) of approximately 30 nM based on our dose-response curve. This is within the same order of magnitude as the EC50 of 85 ± 17 nM established in HEK293 cells, reported by Gomez et al.30 These experiments demonstrated the formation of a neural circuit model within a microdevice that can be subjected to HTS assays conducted within an automated instrument.