Electrophysiological characterization of induced pluripotent stem cell (iPSC) - derived neurons from a chromosome 15q11-q13.1 duplication syndrome (Dup15q) subject. (a) Representative whole cell potassium currents (top) and sodium currents (bottom) recorded from a 12-week-old Idic1-8 iPSC-derived neuron generated using the embryoid body based differentiation protocol. (b) Current-voltage relationship for peak sustained K current (filled triangles) and peak Na current (open triangles) from 12-week-old neurons (n = 16). (c) Representative action potential train from a 12-week-old neuron. (d) Example sweeps of excitatory synaptic currents recorded from a 14-week-old neuron. (e) Group data showing average frequency and amplitude of synaptic currents in 14 week-old-neurons (n = 20).