(a) UMAP plot showing just VPHGLUT clusters 1–5 and 20 (details from Figure 2b). (b) Mouse brain atlas schematic modified from Paxinos, 2012, showing subregions of the MB in a coronal section at distance from bregma of −2.92 mm. Color-coding of subdivisions indicate correlations between transcriptionally distinct subpopulations in (a) and anatomical subdivisions within the MB: cluster 1 (MM, light orange), cluster 2 (ventromedial MnM, dark orange), cluster 3 (dorsomedial MnM, light green), cluster 4 (ML, medium green), cluster 5 (TMNv or ventrobasal MM/ML, dark green) and cluster 20 (LM, brown). (c) Schematic of connections between the MB, hippocampal formation, ATN and VTg comprising the Papez circuit. (d) Schematic parasagittal section illustrating anterograde viral tracing using AAV-DIO-ChR2-EYFP injection in the MB of three cre driver lines (Slc17a6-Cre, Nts-Cre, and Calb1-Cre). Number labels indicate imaged coronal sections. (e) Representative fluorescence images of coronal sections for anterograde tracing in Slc17a6-Cre (n = 3 mice; left), Nts-Cre (n = 3 mice; middle) and Calb1-Cre (n = 2; right) mice at the following approximate distances from bregma: (1) ATN, −0.82 mm; (2) mtt, −1.94 mm; (3) MB injection site, −2.92 mm; and (4) VTg, −4.84 mm. All sections were counterstained with DAPI (blue). Abbreviations: AV (anteroventral), AM (anteromedial), AD (anterodorsal), mtt (mammilothalamic tract), mtg (mammillotegmental tract), and pm (principle mammillary tract).