Induction of αS pathology throughout the neuroaxis 8 months after neonatal brain injection of 25 μg fibrillar 21–140 αS in M20 Tg mice. Tissue sections were stained with pSer129. Dystrophic neurites were diffusely present throughout the brain and spinal cord. The more rounded, Lewy body-like pathology was seen predominantly in the olfactory bulb (OB), motor cortex (MC), amygdala (AMY), dentate gyrus of the hippocampus (DG), thalamus (TH), hypothalamus (HYP), substantia nigra (SN), ventral pons (VP), and both the ventral and dorsal horns of the spinal cord (VH-SC and DH-SC). Lewy neurite-like pathology extending into the cellular processes was more predominantly seen in the piriform cortex (PC), entorhinal cortex (EC), striatum (ST), corpus callosum (CC), and CA1 of the hippocampus (CA1). Tissue sections were counterstained with hematoxylin. Scale bar = 50 μm (OB), 100 μm (MC), 50 μm (PC), 50 μm (EC), 100 μm (ST), 200 μm (CC), 50 μm (AMY), 50 μm (DG), 50 μm (CA1), 50 μm (TH), 50 μm (HYP), 50 μm (SN), 50 μm (VP), 200 μm (VH-SC), and 200 μm (DH-SC).