(a) Expression of dopaminergic neuron genes in day 30 mDA cultures from 6 iPSC lines. 3 biological replicates per line were averaged. Data are normalized to average expression in control lines and presented as 3 CTR vs 3 PD lines. No significant differences were detected using multiple t-tests with Holm-Sidak correction for multiple comparisons. (b) HPLC detection of total dopamine in d30 mDA culture lysates. n=9 CTR n=9 PD not significant p=0.29 two-tailed t-test with Welch’s correction. (c) HPLC detection of released dopamine in aCSF following a 15 min incubation at 37oC. n=9 CTR n=9 not significant p=0.14 two-tailed t-test with Welch’s correction. (d) MEA recording of spontaneous activity from 02iCTR mDA neurons at day 21 of differentiation. (e) MEA recordings of control and YOPD mDA neurons at d30 of differentiation. (f) Average sorted spikes per neuron at d30. Points represent an average of 4 independent wells, n=6 CTR n=6 PD colors indicate iPSC lines. Bar graphs represent mean, error bars represent standard deviation (s.d.).