Fig. 3.

Histological sections from one monkey that showed the recording area in the ventral striatum. Frontal sections at A23, A20, and A18 from top to bottom, which span the recording area along the rostrocaudal direction, are shown. The thick line in the A20 photograph indicates the approximate area where we recorded single-unit responses. Theinset shows a magnified view of an electrolytic lesion marking a recording site in the outlined area of the A20 histological section. A, anterior.