FIGURE 2.

Photomicrographs showing Nissl‐stained sections including the NAcc in human‐56 (a, e), baboon‐12 (b, f), pig‐tailed macaque‐15 (c, g), and capuchin‐16 (d, h). Photomicrographs including the VP in chimpanzee‐36 (i, m), rhesus macaque‐14 (j, n), Japanese macaque‐9 (k, o), and cotton‐top tamarin‐9 (l, p). Each sampling region is indicated by a dashed line. Age in years is listed after each speciman. a.c., anterior commissure; C, caudate nucleus; P, putamen. All sections are 40‐µm thick. Scale = 1 cm.