The main inhibitory cell populations in the cerebellum are deficient in KO. (A–F) WT (A,D,E) and KO (B,D,F) cerebellar sections at P21. (A–D) In WT, GFAP+ Bergmann glia cells (green) are embedded within the Purkinje cell layer (Pcl) and extend their radial fibers throughout the molecular layer (ml). Reelin (Reln, red)+ granule cells are located in the granular layer (gl). In KO, GFAP labels misaligned and fragmented radial fibers of the Bergmann glia with Reln+ granule cells embedded in an abnormal distribution within the molecular layer. DAPI is shown as counterstaining. Merge images are shown. (C,D) are high magnification panels of (A,B), respectively. (E,F) As mentioned in (A–D), GFAP labels normal and fragmented Bergmann glia in WT and KO, respectively. Parvalbumin (PV)+ interneurons are distributed throughout the molecular layer in WT but their distribution pattern is disrupted in the KO being intermingled in the misaligned Bergmann glia. PV also labels mature Purkinje cells, normally labeled in WT and with deficiencies in KO. Scale bars: (A,B) (250 μm) and (C–F) (50 μm).