Fig. 1: Arc structure is identified in neonatal gyrencephalic brains.
a, MRI 3D reconstruction of the postnatal human, pig, marmoset and mouse brains. Two gyrencephalic brains (human at birth (term) and P0-aged piglet) and two lissencephalic brains (marmoset at 4.5 years of age and mouse at birth). b, Nissl-stained serial sections across species taken at birth. Black arrows indicate a cell-dense region extending dorsally from the lateral ventricle. c, Quantification of Arc area relative to total brain area (Arc area ratio, %) by Nissl staining at birth. Two-tailed unpaired t test (*P = 0.0268, ****P < 00001). The data are presented as mean ± s.e.m. Sample size is provided as source data. d, Correlation (Pearson’s r) between GI with the Arc area ratio across species (r = 0.8291, ****P < 0.0001). e, Arrangement of DCX+ cells (green) near the ventricular wall across species. Insets 1–4 (right of schematic) show confocal images of DCX+-enriched regions. Blood vessels are shown in red; dark green clusters correspond to DCX+ cellular densities. f, Quantification of DCX+ cells near the ventricular wall (green line). Quantification of BV areas, labeled by alpha smooth muscle actin (α-SMA), relative to total Arc area (BV ratio, %, red line) across species. The data are presented as mean ± s.e.m. Human (n = 4), piglet (n = 3), marmoset and mice (each n = 2). g, Left, confocal microscopy of single molecule fluorescence in situ hybridization (smFISH) for RNA expression of GABAergic-neuron markers (GAD1, GAD2 and DLX2) in the neonatal human and piglet brain. DCX protein expression was codetected. Right, quantification of DCX+ GAD1+ cells of all DCX+ cells across tiers. Data means ± s.e.m., n = 2 individuals (each species) in three independent experiments. Sample size is provided as source data. h, Triangle plot showing a comparison of core Arc features across species. All values are normalized to humans (raw values are shown as source data), and two-way MANOVA analysis is shown in Supplementary Table 2. Red dotted line (human), blue dotted line (piglet), green dotted line (marmoset) and black dotted line (mouse). LV, lateral ventricle; St: striatum; BV, blood vessel.
