Fig. 1: Representative images for each grade of AS accumulation of the neural structures within the submucosa and muscularis propria.

a, c, e, g, i, k Representative images of neural structures (ganglia and interganglionic nerve fibers) that were assigned the same grade by all raters. The rating is based on the density of dots and fibers within the myenteric and submucosal plexuses or nerve bundles, as identified via pAS immunostaining (grade 0, negative; grade 1, sparse; grade 2, moderate; and grade 3, frequent). b, d, f, h, j, l For the confirmation of neuronal cells, NF immunostaining is performed in adjacent sections. The low-magnification insets display the anatomic locations of the respective neural structures. All representative slides are sectioned from the stomach except c, d from the rectum. Scale bars: black, 100 μm, and gray, 3 mm. AS alpha-synuclein, pAS phosphorylated AS, NF neurofilament.