Fig. 2: Drd1+ and Drd2+ BLA neurons innervate the entire span of the ventral striatum.

A Schematic of approach for identifying BLA Drd1+ and Drd2+ synaptic innervation of the ventral striatum. B Maps of BLA injection sites for Drd1-Cre (left) and A2a-Cre mice (right), where each color represents individual mice. C Representative images showing direct innervation of BLA neurons into the ventral striatum in both Drd1- and A2a-Cre mice. Inset locations denoted by square white box, inset sale bar = 10 µm. D Quantification of synaptophysin puncta in Drd1-Cre (n = 3, 2/1/sex) and A2a-Cre (n = 3, 2/1/sex) mice. Mean ± SEM. E Approach for defining whether, and if so, BLA neurons send contralateral projections to the ventral striatum using an AAV encoding synaptophysin. GFP in the BLA in one hemisphere and synaptophysin.mRuby in the BLA in the opposite hemisphere. F Representative images from one mouse of ipsilateral and contralateral projections from the BLA to the ventral striatum following injection as in E. These example images show that while some BLA neurons transverse into the contralateral ventral striatum, qualitatively, the bulk of input is ipsilateral. G Diagram of approach for identifying BLA Drd1+ and Drd2+ projecting neurons to the NAc and TuS in the ventral striatum. H Percentage of the Drd1+ and Drd2+ neurons within the BA that project to the NAc (red), TuS (green), or both (yellow) (n = 3 mice/genotype, 2/1/sex, 5–6 sections/mouse). I Representative image of a retrograde injection in a Drd1-Cre mouse and J the anterior to posterior span of VS projecting BLA neurons. Scale bars = 500 µm. PCx piriform cortex, NAcC and NAcSh nucleus accumbens core and shell, respectively, BLA basolateral amygdala, BA basal amygdala, LA lateral amygdala.