Fig. 2

C-Fos expression in various brain regions in response to looming stimulus in young and aged mice. (a) Schematic representation of brain structures selected for c-Fos immunohistochemistry analysis [Bregma − 1,82 (top) and − 4,16 mm (bottom)]. (b) Photomicrographs of brain sections following c-Fos immunohistochemistry and counterstaining with Hoechst. Arrows indicate the presence of c-Fos immunolabeled (c-Fos⁺) cells in the BLA of control (Ctrl) and looming (Loom) animals (scale bars = 100 μm/25 µm). Density analysis of c-Fos⁺ cells in the dentate gyrus (DG) and the CA3 region of the dorsal hippocampus, the basolateral (BLA), central (CeA) and lateral (LA) amygdala, the lateral posterior thalamic nucleus (LPTN), the superior colliculus (SC) and its upper layers (uSC), the dorsolateral periaqueductal gray (dlPAG) and the parabigeminal nucleus (PBGN) of (c) young mice in the “Home-Cage” (n = 4), “Control” (n = 7) and “Looming” (n = 12) conditions and (d) aged mice in the “Home-Cage” (n = 4), “Control” (n = 8) and “Looming” (n = 7) groups (female and male are represented by circles and triangles, respectively). Data are represented as mean ± SEM ; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by Tukey’s post-hoc tests.