Paraffin section, 7 μm, PAS-hematoxylin. The hippocampal formation (dentate gyrus, hippocampus CA1, Ca2, and CA3, and subiculum) occupies the center of the field, and a sector of cerebral neocortex lies in the left part of the field of a 15-month-old knockout mouse. Glial cells contain increased glycogen in the radiatum and lacunosum layers of the hippocampus, in the dentate gyrus and subiculum, in the corpus callosum dorsal to the hippocampus, while glycogen-rich glial and vascular cells lie in the gray matter of the cerebral cortex (top left) and thalamus (left of inset). The inset shows lysosomal fluorescence (white), due to binding of the filipin reagent to lysosomal cholesterol in the apical cytoplasm of CA1 pyramidal neurons, even though these cells, delimited by the black bars in the colored part of the figure, are predominantly glycogen-free. Bar: 500 μm.