Fig. 1

DG interneurons are highly connected with MS GABAergic neurons. A Schematic for monosynaptic retrograde tracing of GABAergic neurons in the DG of Vgat-Cre mice. B Representative images of mCherry-Rabies virus labeling in the DG of Vgat-Cre (scale bar = 200 μm). C Representative images of mCherry and GFP labeling in the starter cells from the retrograde tracing of DG GABAergic neurons (scale bar = 50 μm). D Representative images of mCherry labelied input cells in the MS and DB of 5 month Vgat-Cre mice. E Quantification of Vgat-Cre connectivity in 5 month Vgat-Cre mice. Data from 4 Vgat-WT mice. DB Diagonal band of Broca, MS Medial Septum, VTA Ventral Tegmental Area, cCA contralateral Cornu Ammonis, cDG contralateral Dentate Gyrus, HY  Hypothalamus, ENT Entorhinal cortex, DR Dorsal raphe, LS Lateral Septum, TH Thalamus, SUB Subiculum, PIR Piriform cortex, mPFC medial Prefrontal Cortex, LC Locus coeruleus. F Representative images of mCherry-labeled input cells in the MS co-labeled with anti-GABA antibodies (Yellow arrows indicate co-localization) in 5 month Vgat-Cre mice. (scale bar = 25 μm). G–H Quantification of mCherry⁺, mCherry⁺GABA⁺ cells and percentage of mCherry⁺GABA⁺ in total mCherry⁺ cells in retrograde labeling of MS neurons in 5 month Vgat-Cre mice. 3 mice and 3 slices/mouse were counted