a, HE-stained sections of the cerebral cortex, the gracile nucleus and cerebellum from control (Atg5flox/+; nestin-Cre) and Atg5flox/flox; nestin-Cre (Atg5flox/flox) mice at three months of age. Purkinje cells are indicated with arrowheads. Arrows indicate eosinophilic spheroids, which represent axon swelling. Scale bar, 10 µm. 