Fig. 3. Synaptic dysfunction observed in DA neurons derived from patients with sPD compared to healthy controls.

We recorded a total of 113 control and 57 sPD neurons derived from 3 control and 4 sPD patients. a and b Representative traces of evoked action potentials of control and sPD neurons, respectively. c sPD DA neurons were hypoexcitable compared to control neurons as measured by the total evoked action potentials. d and e Example recordings of excitatory post-synaptic currents (EPSCs) in control and sPD DA neurons, respectively. f Reduced amplitudes of EPSCs in sPD DA neurons as compared to control DA neurons. g The rate of EPSCs was not significantly different between sPD and control neurons. h The cumulative distribution of EPSC amplitudes in control and sPD neurons. i The capacitance was not significantly different between control and sPD neurons. j and k Examples recordings of the sodium and potassium currents obtained in voltage-clamp mode from a control and an sPD neuron. l Sodium currents were decreased in sPD DA neurons compared to controls. m Fast potassium currents and n slow potassium currents were not significantly different between sPD and control neurons. The results were acquired from 2 to 3 separate differentiation cycles for each of the cell lines. The sodium and potassium currents were analyzed using a one-way ANOVA, while all other comparisons were analyzed using the Mann–Whitney U test. Error bars indicate the standard error of the mean (SEM).