Fig. 4From: Establishment of high reciprocal connectivity between clonal cortical neurons is regulated by the Dnmt3b DNA methyltransferase and clustered protocadherinsEffect of Dnmt3b deficiency on the morphology and synaptic connectivity of clonal neurons. a Barrel structure visualized by cytochrome oxidase reaction (CO) in a chimeric mouse produced using Dnmt3b-knockout (KO) induced pluripotent stem cells. Scale bar: 200 μm. b, c Distribution (b) and proportion (c) of Dnmt3b-KO cells in the analyzed area in each column. The number of columns is 12, 14, and 13 for P9–11, P13–16, and P18–20, respectively. P = 0.09 (Kruskal–Wallis test). Scale bar: 100 μm. d Dnmt3b-KO spiny stellate cell (red, upper) and traces of its soma and dendrites (lower). Scale bar: 50 μm. e–g Total dendritic length (e), number of dendritic branches (f), and Sholl analyses (mean ± SEM, g) of Dnmt3b-KO (purple, n = 9 cells sampled from 4 mice) and wild-type (WT; gray, the same as shown in Fig. 2) spiny stellate cells at P18–20. A bar indicates the mean (e, f). No significant differences in morphological parameters between these two groups were observed; P = 0.41 (e), P = 0.41 (f), and P > 0.14 (g) (t test). h–k Dual whole-cell recordings from Dnmt3b-KO GFP-positive excitatory neurons (P-P) pairs. h Representative average (n = 20) traces of presynaptic spikes (pre) and resultant excitatory postsynaptic currents (post) between Dnmt3b-KO P-P pairs with a one-way (upper) or reciprocal (lower) connection. i Percentage of Dnmt3b-KO P-P pairs with one-way (blue), reciprocal (magenta), or no (gray) connections. Numbers of recorded pairs are indicated on the bars. Number of mice: P9–11(n = 9), P13–16 (n = 11), P18–20 (n = 12). *P < 0.05: connection probabilities in different age groups (χ2 test with a 3 × 2 matrix after Bonferroni correction). j, k Connection probability (j) and reciprocity (k) of Dnmt3b-KO P-P (purple) and wild-type P-P (green) or GFP-positive and -negative neuron (P-N) (gray) cell pairs. **P < 0.01 compared with wild-type clonal pairs (Fisher’s exact test)Back to article page