Figure 1.
Reprogrammed Neurons Functionally Mature over Time
(A) Endogenous GFP expression can be detected in a reprogrammed neuron (unstained tissue) and was used to identify cells for recordings.
(B) Post-recorded biocytin-filled neuron shows mature neuronal morphology including dendritic spines.
(C–F) The reprogrammed neurons show maturation in membrane-intrinsic properties from 8 to 12 w.p.i., as shown for (C) membrane capacitance (Cm), (D) input resistance, (E) resting-membrane potential (RMP), and (F) frequency in spontaneous postsynaptic activity (for Cm, input resistance, and RMP, n = 6 [8 w.p.i.], n = 7 [12 w.p.i.], and n = 7 [endogenous]; for spontaneous postsynaptic activity, n = 4 [5 w.p.i.], n = 6 [8 w.p.i.], n = 7 [12 w.p.i.], and n = 5 [endogenous]).
(G and H) Traces showing (G) inhibitory (GABAergic) activity that was blocked with picrotoxin, a GABAA receptor antagonist and (H) excitatory activity that was blocked with CNQX, an AMPA receptor antagonist.
(I) Reprogrammed neurons show repetitive firing already at 5 w.p.i. and continue to show that at 8 and 12 w.p.i.
(J) The number of neurons with postsynaptic activity increases over time.
All data are presented as means ± SEM; ∗p < 0.05 in one-way ANOVA. Scale bars: (A and B), 25 μm. See also Figure S1.