Expression of human α-Synuclein in populations of principal neurons. Triple fluorescent labeling reveals that immunoreactivity of both hα-Syn (green channel) and pan α-Syn (blue channel) is absent from neurogranin-positive mitral cells (NG, red channel) in the olfactory bulb (arrowheads in A). In contrast, a subset of neocortical (B) and hippocampal (C) pyramidal neurons expresses α-Syn; co-localization of all three color channels (arrows) is indicated by the occurrence of whitish pixels. Single channel images are rotated clockwise in panels A and C. Abbreviations: neurogranin (NG), stratum plexiforme externum/internum (spe/i), stratum mitrale (smt), stratum oriens (so), stratum pyramidale (sp), stratum radiatum (sr), cortical layers III and IV (III and IV), cornu ammonis area 3 (CA3). Scale bar = 50 μm.