Figure 3. Increased subcerebral connectivity in somatosensory cortex of Pum2 cKO and TDP43^A315T mice.

(a) Schematic representation of cholera toxin subunit B (CTB) injections at the midbrain/hindbrain junction (pons) for retrograde labeling of subcerebral projection neurons (SCPNs), including corticospinal PNs (CSMN) and corticopontine PNs (CPoPN). (b) Coronal sections from primary somatosensory cortex (S1) of controls, Pum2 cKO, and TDP43^A315T mice at P7 traced for SCPNs without (top) or with DAPI (bottom) staining. S1 columns merged with DAPI are divided into eight equal bins. White rectangles indicate bins 3 and 4. (c) Quantification of retrogradely labeled SCPNs in equal-sized bins for the three genotypes. Analysis of bins 3 and 4 is shown separately in the left panel and combined in the right panel. Data are shown as means ± standard error of the mean (SEM), n = 3 for each genotype. **p≤0.01, ***p≤0.001, two-tailed t-test. Pum2 cKO: Pum2^fl/fl; Emx1^Cre; II–IV, V, VI: layers II–IV, V and VI, respectively. Scale bars: 100 μm.