a–c Membrane properties of an mCherry+ astrocyte recorded in an acute dorsal midbrain slice prepared from a WT mouse that was infected with the control virus AAV–mCherry at 30 DPI. Membrane voltages (b) and currents (c) were recorded in current- and voltage-clamp modes, respectively, in responses to the step current or voltage commands. Arrow indicates the cell recorded (a). d–h Membrane functions of iN cells (mCherry+, d) in slices of the dorsal midbrain that were prepared from WT mice infected with AAV–Neurog2/mCherry virus at 30 DPI. Membrane voltages (e) and membrane currents (f) were recorded in current- and voltage-clamp modes, respectively. The membrane currents were blocked with NBQX. g EPSCs were recorded in the mCherry+ cells of iN cells. h Double staining of Biocytin and mCherry on mCherry+ cells from AAV-Neurog2/mCherry-infected slices. Scale bar: 25 μm. i The comparison of membrane capacitance among AAV-mCherry-infected cells (red), local neurons (purple), and AAV-Neurog2/mCherry-infected cells (light blue). A one-way ANOVA revealed a significant effect of group (F[2,49] = 9.31, p < 0.001), followed by Tukey’s multiple comparison test. j The comparison of input resistance among AAV-mCherry-infected cells, local neurons and AAV-Neurog2/mCherry-infected cells. A one-way ANOVA revealed a significant effect of group (F[2,49] = 33.50, p < 0.001), followed by Tukey’s multiple comparison test. A total of 31 cells, 14 cells, and 15 cells were recorded in astrocytes, local neurons, and Neurog2-iNs, respectively. ** And *** represent 0.001 < p < 0.01 and p < 0.001, respectively; n.s. denotes not significant. k, l The fine structure of synapse between iN cells and local cells by immunogold electron microscopy. Brown-colored areas in (k) and (l) show iN cells (mCherry+, marked by gold particles, red arrows); light green areas (local neurons) represent presynaptic structure (k) and postsynaptic structures (l), respectively; White arrowheads indicate synaptic vesicles. Yellow arrows indicate connective buttons between induced neurons and host cells. Scale bar: 200 nm.