Figure 8. Covariance between Input Regions and Summary of Findings.

(A and B) Pairwise correlations and cluster analysis of six regions counted in seven Sert-cre (A) and eight Gad2-cre (B) experiments. Heatmaps represent high correlation (red) or anticorrelation (blue) between regions. Cortex includes all neocortical regions anterior to the corpus callosum crossing.

(C–E) Example graphs showing a strong negative correlation between cortical and medullary inputs in Sert-cre tracing experiments (C), a strong negative correlation between central amygdalar and medullary inputs (D), and a strong positive correlation between inputs from the central amygdala and BNST (E) in Gad2-cre tracing experiments. Each dot is a separate tracing experiment. Values shown are Pearson correlation coefficients with uncorrected p values from a two-tailed test.

(F) Summary of inputs to the DR on a schematic sagittal section showing regions that make up greater than 1% of total inputs. Percentage of total input is coded by gray scales (inset). Stars indicate biased input to DR serotonin (blue) or GABA (red) neurons. The primary neurotransmitters expressed by input regions are shown as small circles as indicated in the inset.

(G) Schematic of local inputs to DR serotonin neurons. Blue, serotonergic inputs; red, GABAergic inputs. The number of circles in each region reflects the quantitative distribution of local inputs of each cell type.

Ventricles Serotonin biased GABA biased Glutamatergic GABAergic Peptidergic Other

Abbreviations: Aq: aqueduct; BNST: bed nucleus of the stria terminalis; CeA: central amygdala; CP: caudoputamen; DCN: deep cerebellar nuclei; DW: dorsal wing; EAM: extended amygdala; LHb: lateral habenula; MRtN: midbrain reticular nucleus; NAc: nucleus accumbens; PVH: paraventricular hypothalamic nucleus; VW: ventral wing