Fig. 1
Prairie voles have more Oxtr positive cells than meadow voles in the nucleus accumbens. (A, B) Representative in situ hybridization images of dopamine receptor 1 (Drd1), dopamine receptor 2 (Drd2), and oxytocin receptor (Oxtr) in the nucleus accumbens core of prairie voles (A) and meadow voles (B). Scale bar = 200 μm in low magnification images (left) and 50 μm in high magnification images (right). (C) Cell quantification using Fiji Image J: DAPI stained cells are computationally identified and thresholding is manually adjusted to remove background and detect nuclei. Nuclei are outlined, numbered and an outline mask is generated to overlay on other channels to then identify positive cells for each transcript channel. (D-F) Quantification of transcript presence or absence within a DAPI mask in the nucleus accumbens core (D), medial shell (E), and lateral shell (F) of prairie voles and meadow voles. There was a main effect of transcript identity and a significant interaction between species and transcript identity. Post hoc species tests revealed that prairie voles had significantly more Oxtr+ and no transcript(NT)+ cells than meadow voles in all subregions, while meadow voles had more Drd2+ cells. No consistent species differences were observed for Drd1+ cells. Post hoc transcript identity within species tests revealed that Drd1+ and Drd2+ cells were more abundant than Oxtr+ and NT+ cells in both species. In prairie voles, Drd1 predominated over Drd2 in the medial and lateral shell, while the two were comparable in the core. Oxtr+ cells were consistently more abundant than NT+ cells. In meadow voles, Drd2+ cells were most abundant across regions, and Oxtr+ cells more abundant than NT+ cells, except in the lateral shell. Species-level differences are annotated directly in the figure (Šidák-corrected post hoc comparisons). Due to the number of significant within-species differences between transcript identity groups, those comparisons are not shown visually but are fully reported in Supplementary Table S1. Error bars show SEM. n = 13 per group. ** p < 0.01,*** p < 0.001, **** p < 0.0001.
