Supplementary Figure 9: Differential connectivity with the amygdala, nucleus accumbens, and BST.

(a) Amygdala-projecting neurons are distributed through layer 3 in the ProSUB, SUBv, and SUBvv whereas anterogradely-labeled fibers from the amygdala terminate primarily in the molecular layer (dashed white lines outline the pyramidal layer). Most cortical amygdala nuclei (COApl, PAA, COAa, etc.) terminate in the superficial part of the molecular layer, but the BMAp and BLAp innervate the deep part of the molecular layer and layer 3 and the caudal BLAa has an entirely unique projection pattern (see Fig. 7b). (b) Injection of anterograde and/or retrograde tracers into the SUBv and SUBvv reveals two distinct topographic connectivity patterns within the amygdala (dashed white lines outline the basolateral amygdala complex). SUBvv fibers and retrograde labeling are more robust in medial amygdala nuclei (particularly MEApd) whereas SUBv fibers and retrograde labeling are denser in BMAp, BLAp, and parts of the LA. (c) SUB projections target topographically distinct zones within the ACB (dashed white lines outline approximate boundaries of ACB). ProSUB fibers innervate the lateral core and shell of the ACB whereas SUBv fibers target the medial ACB core and middle part of the ACB shell. The SUBvv projects distinctly to the dorsomedial tip of the ACB shell and the CA1v projections overlap the area of the combined SUBv and SUBvv terminal fields. (d) Differential innervation of BST subnuclei by hippocampal inputs (white dashed lines outline BST subnuclei, anterior BST on top, posterior BST on bottom). The anterior BST is primarily innervated by the SUBv and SUBvv. Few ProSUB fibers enter into the BST. SUBv fibers are located throughout the anterior BST while SUBvv fibers are restricted to the BSTam/BSTdm. In the posterior BST, the BSTif/tr region is commonly innervated by ProSUB, SUBv, SUBvv, and CA1v. For the number of tracer experiments and cross-validated results, see the Supplementary Methods.