(A–C) Coronal optical sections showing typical distributions of inputs in the ventral striatum. A comparison of the typical ‘patch’ structure of inputs from the ventral striatum (to VS-projecting or DS-projecting dopamine neurons, for example) with the atypical ‘patch-less’ structure of inputs from the striatum to TS-projecting dopamine neurons. (D) Percentage of input neurons within the ventral striatum (core, medial shell, and lateral shell combined) in each condition. Red dotted line indicates the percentage expected based on chance distribution throughout the brain, while green dotted line indicates the average percentage among all animals. (E) Horizontal optical section showing a typical distribution of inputs in the ventral striatum, with many input neurons in tight clusters. Bar represents 2 mm. (F) A zoomed view of E, taken from the indicated box. Clusters are dispersed along the A-P axis, so two planes are used to display them in coronal sections: the black arrow indicates the anterior plane and the white arrow indicated the posterior plane. (G–H) Coronal optical sections showing the two planes indicated above, as well as a graphical representation of the five patches in those planes. (I) Among labeled neurons in the ventral striatum, the percentage within the patches in each condition. Red dotted line indicates the percentage expected based on chance distribution throughout the nucleus accumbens, while green dotted line indicates the average percentage among all animals. (J) Among labeled neurons within the patches, the percentages within each patch in each condition. Green arrows point to patch 2, cyan arrows point to patch 3, and yellow arrows point to patch 5. More detailed description of the patches shown in Figure 7—figure supplement 1.