Distribution of FAIM_L-immunoreactive cells during the development of mice brain. A–E, In the cortex, many neuronal cell bodies show immunohistochemical labeling. A, At E16, neurons in the CP and SP contain FAIM_L. B, At P0, some neurons in the incipient layer V are FAIM_L-positive cells. In postnatal stages, many neuronal cell bodies and dendrites present FAIM_L-immunolabeling, mainly in layer V (C, arrows). F–H, In the hippocampus, many pyramidal neurons and hippocampal interneurons express FAIM_L, and granular neurons in the dentate gyrus (DG) present weak immunostaining. Some hippocampal interneurons scattered in all hippocampal layers show a strong immunostained signal (F, H, arrows). I–L, In the cerebellum, the soma and dendrites of Purkinje cells show immunohistochemical staining at all postnatal stages analyzed. Also, some interneurons located in the granular layer (GL) express FAIM_L (J, arrows). M, N, Immunofluorescence colocalization (arrows) of FAIM_L and NeuN proteins in cortical layer V at P5. P–R, Immunofluorescence colocalization of FAIM_L and calbindin in Purkinje cells (arrows) in the adult cerebellum. MZ, Marginal zone; IZ, intermediate zone; SVZ, subventricular zone; VZ, ventricular zone; CA1–CA3, hippocampal fields; so, stratum oriens; sp, stratum pyramidale; sr, stratum radiatum; slm, stratum lacunosum-moleculare; sm, stratum moleculare; sg, stratum granulosum; h, hilus; ML, molecular layer; PCL, Purkinje cell layer; GL, granule cell layer. Scale bars: (in A) A, B, F, J, H, 100 μm; (in C) C–E, 100 μm; G, 100 μm; (in I) I, K, L, 100 μm; (in M) M–O, 25 μm; (in P) P–R, 100 μm.