Fig. 1

a-Syn inclusions were observed in the axons of the input and output of neural connections in the striatum. An immunohistochemical evaluation of p-syn inclusions in the input and output of neural connections in the striatum (Str) was conducted in the brains of mice 6 months after the injection of mouse a-syn PFFs seeds into the striatum. a Medium spiny neurons (MSN) of the striatum stained with anti-DARPP-32 antibody (DARPP-32, red) showed anti-p-syn #64 (p-syn, green)-positive deposits. Z-stack confocal images are shown as merged images. Side views are examined the xz and zy planes. b Schematic of the input and output fibers of the striatum. CTX: cortex, Str: striatum, SNpc: substantia nigra pars compacta, SNr: substantia nigra pars reticulata. c Double staining of the anti-p-syn#64 (p-syn, green) and each axonal marker for the input and output of the striatum. In the retrograde direction, p-syn deposits (threads) were detected in axons from the cortex, stained with anti-neurofilament H antibodies (NFH, red) (upper panel, left), and in axons from the SNpc, stained with anti-tyrosine hydroxylase antibody (TH: red) (upper panel, center and right). In the anterograde direction, p-syn deposits were detected in axons from the striatum to the SNr, stained with anti-mSCN4B-C antibodies (β4, red) (lower panel, left), or with anti-Nav1.2 antibodies (Nav1.2, red) (lower panel, right). Arrows indicate p-syn in the axons, with each axonal marker. d Following injection of a-syn PFFs into the striatum, at 0.75,1.5, 3, and 6 months, the typical shape of the inclusions was evaluated as shown. Scale bars, 10 μm (a, c), 50 μm (d)