Localization of WFA and brevican reactivity in PNNs. Brevican immunoreactivity was found in (A and C) neuropil and PNNs of cortical layers II, III, deep layer IV and V. WFA immunoreactivity is predominant in (B and C) PNNs of cortical layer III. A higher magnification of cortex reveals PNNs that are positive for (D) brevican and (E) WFA reactivity. A confocal micrograph (G) of retrosplenial cortex stained with anti-brevican (green), biotinylated-WFA (red) and DAPI (blue) demonstrates a small subpopulation reactive for both anti-brevican and WFA (arrows). While the majority of PNNs showed only brevican immunoreactivity, some were identified as only WFA reactive (denoted by asterisk). Images A-C were captured at 100× magnification, D-F were captured at 200× magnification and confocal image G was captured at 630×. Scale bar represents 100 μm.