Autoradiographic distribution of 11C‐PE2I in the caudate nucleaus, putamen (A, B), and cerebellum (C, D) in a control cat (A, C) and after 1 week of daily injections of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (B, D). Histogram representing 11C‐PE2I radioactivity measured in the aforementioned regions of interest.