Fig. 3

Both AST-derived dopamine neurons and mouse dopamine neurons overexpressing α-synuclein exhibit bursting firing pattern. The experiments and analyses were performed in parallel and via a blinded experimental design. a₁ Representative trace of a spontaneously active NAS-derived dopamine neurons shows a mixture of single spikes and small burst activity with an underlying “pacemaker-like” periodicity. a₂ Representative trace of a spontaneously active AST-derived dopamine neuron shows a unique high up-state (depolarized plateau) and high frequency of spontaneous activity with a pause between subsequent broadbrimmed bursts. a₃ Time courses of instantaneous firing frequency, action potential half-width and amplitude obtained from (a₁) and (a₂). b₁ Representative trace of a spontaneously active wild type mouse dopamine neuron obtained from midbrain primary neuronal culture. b₂ Representative trace of a spontaneously active mouse dopamine neuron overexpressing α-synuclein. b₃ Time courses of instantaneous firing frequency, action potential half-width and amplitude obtained from b₁ and b₂. c Phase-plane plot of action potentials generated from (a₁) and (a₂). Unlike AST-derived dopamine neurons, the action potentials in NAS-derived dopamine neurons show a smooth and slower onset at initiation site. d Phase-plane plot of action potentials generated from b₁ and b₂. e Interspike histogram (in ms) from top to bottom: NAS-, AST-derived neurons, WT mouse dopamine neurons, and mouse dopamine neurons overexpressing α-synuclein. n corresponds to the total number of spikes for each histogram