FIG. 1.

Apoptotic cell death in the cortex of polysialic acid-deficient mice. (A) Vibratome sections showing sagittal views of 1-month-old WT (upper) and II^−/−/IV^−/− (lower) mice. CB, cerebellum; CX, cerebral cortex; HC, hippocampus; LV, lateral ventricle; OB, olfactory bulb. (B to E) Apoptotic cells (brown) in sagittal sections of 1-month-old WT (B and C) and II^−/−/IV^−/− (D and E) mice were detected. Nuclei were stained by cresyl violet. The cerebral cortex (B and D) and hippocampus (C and E) are shown. Many cells undergo apoptosis in the SVZ of double mutant mice (arrows in panel D). CC, corpus callosum; DG, dentate gyrus. Bar, 0.2 mm.