Fig. 1.

Learning (A), group (B), and learning × group interaction effects (C) revealed by a liner mixed effect model (LME) to olfactory stimulus presentation. Activation regions are overlaid onto a standard rat atlas to facilitate anatomical localization and show statistically significant differences in (A) response to S+ vs. S− in insula (spatial extent 10 voxels) and NAc (9 voxels), (B) difference between cocaine and sucrose groups in medial prefrontal (8 voxels) (infralimbic, prelimbick and cingulate cortices) and dorsal striatum (9 voxels), and (C) double dissociation response pattern in dorsal striatum (7 voxels) to S+ and S− in cocaine and sucrose groups. Note, spatial extent of significant clusters for Figs. 1 and 2 is based on a resampled voxel size of 0.14 × 0.14 × 1 mm³ for coregistration to a brain atlas and 0.14 × 0.14× 0.18 mm³ for coregistering to T1 images, respectively.