FIGURE 1. Definition of VOIs for putamen, caudate, thalamus, and white matter (left), mesencephalon (middle), and cerebellum (right) in transversal slices of the ¹¹C-(+)-McN5652-PET template. VOIs were composed of circles of 4.1-mm radius drawn in appropriate number of slices (mesencephalon, no. of slices = 3/no. of circles = 9/no. of voxels = 50; putamen, 4/24/166; caudate, 6/12/83; thalamus, 4/16/105; cerebellum, 5/40/273; white matter, 8/16/108).