Figure 2. Overview of Whole Brain Input to DR Serotonin and GABA Neurons.

(A and B) Coronal sections of a Sert-cre (A) and a Gad2-cre (B) tracing brain showing the distribution of presynaptic partners. Approximate section planes are shown in the top right on a sagittal section of a schematic brain, with approximate distance (anterior-posterior) from the bregma. Images at the bottom are higher magnification views of the rectangular regions on the top images.

(C) Six horizontal sections of one hemisphere of a Sert-cre tracing brain showing the location of presynaptic partners. Approximate section planes and distances from bregma are shown in the top right on a schematic sagittal brain section.

(D) Inputs to DR serotonin or GABA neurons from eight brain regions, shown as the proportion of the total cells counted that are located in a region. Dots represent four individual Sert-cre (blue) and Gad2-cre (red) tracing experiments. Serotonin neurons receive a greater proportion of their input from the cortex. BNST, bed nucleus of the stria terminalis; IPAC, interstitial nucleus of the posterior limb of the anterior commissure; Hypoth, hypothalamus; Amyg, amygdala; Medu, medulla; Thal, thalamus; Cereb, cerebellum; Striat, striatum; HP, hippocampus.

Scale, 250 μm. Statistical analysis here, and in Figures 3 and 5, used two-way ANOVA on normalized cell counts with Bonferroni corrections (see Experimental Procedures). Hypothalamus values are underestimates, as not all subregions were counted (see Table S1). In this and subsequent figures, error bars indicate SEM. Significance notation: *p < 0.05; **p < 0.01; ***p < 0.001. Figure S2 shows horizontal and sagittal views of inputs to DR serotonin and GABA neurons from 3D-reconstructed coronal sections. Figures S3 and S4 show starter cell distributions for each of the eight experiments used.