Fig. 2: SuM GLU neurons projecting to the septum and to the paraventricular thalamic nucleus mediate positive and negative reinforcements, respectively.

a Schematics showing Cre-specific virus injections into SuM and optogenetic stimulation sites in Sept (n = 23 mice) vs vSub (n = 7 mice) or Sept vs PVT (n = 12 mice). Data are mean lever presses with SEM for each group. Gray, orange, and purple circles indicate data with septal, vSub, and PVT stimulation, respectively. b Summary of active lever-presses (mean − SEM) per session. See (a) for procedure and n’s. In addition, AAV was injected into VTA with fiber placed in septum (n = 6 mice). ^**p’s < 0.005, SuM:Sept^vGlut2 responding more than any other groups over sessions 3–7, Tukey HSD post hoc test. c c-Fos expression after stimulation at respective sites. Arrows indicate the tips of optic fiber; green labels indicate vGlut2 neurons expressing ChR2 (scale bar = 200 µm); and c-Fos-ir is shown in red (scale bar = 100 µm). d c-Fos counts (mean + SEM). c-Fos counts in septum (stimulation, n = 8 mice; non-stimulation, n = 9 mice) and PVT (stimulation, n = 6; non-stimulation, n = 5) were significantly greater when stimulated than when not (unpaired t-test, ^***p’s < 0.001). In the vSub, c-Fos counts were significantly greater in the hemisphere ipsilateral to stimulation than contralateral to stimulation (n = 8 mice) or when not stimulated (n = 7 mice). ^*p < 0.001, Bonferroni test. e Schematic of optogenetic preparation of within-subject comparison of SuM:Sept^vGlut2 vs SuM:PVT^vGlut2 pathways in real-time place preference. f Schematic of real-time place preference chamber. The stimulation compartment (STM) is shown with a dotted line. g Time spent in stimulation side (n = 8 mice; mean + SEM) of the real-time place preference/aversion chamber during baseline (no stimulation) session and stimulation session with septal or PVT stimulation. ^**p < 0.001, ^*p < 0.01, Bonferroni test. h Example heatmaps of mouse position showing time spent in each compartment. Warmer colors indicate more time spent in that area. Source data are provided as a Source Data file.