Light microscopy analysis of BrdU-positive cells in p75NTR (+/+) and (-/-) dentate gyrus. Coronal sections of the dentate gyrus harvested from p75 NTR (+/+) (B, D) and p75 NTR (-/-) (C, E) transgenic mice were examined. (A) Coronal schematic of anterior and posterior dentate gyrus (modified from ). In p75 NTR (+/+) tissues (B and D), BrdU-positive cells are found in a characteristic arrangement in the SGZ adjacent to the dentate gyrus in both anterior (B) and posterior (D) sections. Labeled cells are also present in the hilar regions (arrows). In p75 NTR (-/-) mice (C and E) an apparent decrease in the number of BrdU-positive cells was found in both anterior (C) and posterior (E) regions. Labeled cells are absent in the hilar regions in p75NTR (-/-) (arrows in C and E). (F, G) Higher magnification of labeled SGZ cells demonstrates characteristic aggregation of progenitor cells in p75NTR (+/+) sections with less aggregate apparent in (-/-) sections. Scale bar 25 μm. Abbreviations: ant: anterior; post: posterior; sgz: subgranular zone; DG: dentate gyrus. Scale bar: 100 μm.