Figure 7.

(a) Experiment 2 (N = 17, regular alternation of high a low reward trials). (b) Experiment 3 (N = 20, regular occurrence of targets). The overlays show t values for the contrast high vs. low reward during the foraging patches, thresholded for illustration purposes at p < 0.01, uncorrected. In the insets in the bottom row, percentages of classification of voxels across the sample in the iron-rich region of the brainstem (attributable to SN pars reticulata) are shown by overlays in light blue (from the segmentation algorithm used in the registration). The classification data are the same as in Figs. 2a and 3.