Heterogeneity in mGluR1-TRPC3 signaling, and in overall gene expression, in lobules IV/V, lobule X, and the flocculus. a, Schematic of the postsynaptic signaling pathway involved in the slow EPSC at PF to Purkinje cell synapses (combined and adapted from Hartmann et al., 2011; Kano and Watanabe, 2017; Hirai and Kano, 2018; Cole and Becker, 2023). b, Visualization of gene expression heterogeneity in single-nucleus RNA-seq data of 16,634 Purkinje cells, from Kozareva et al. (2021). The dot plot shows the scaled expression of selected genes of interest across cerebellar regions. The regions of interest are highlighted with appropriately colored boxes (Flocc = flocculus). The following transcripts code for the proteins of interest in b: Trpc3, TRPC3; Grm1, mGluR1; Itpr1, IP₃ receptor; Prkcg, PKCγ; Plcb, isoforms of PLCβ; Gabbr, GABA_B receptor; Grid2, GluD2 receptor; Dgkg, DAG kinase isoforms; Pld1, phospholipase D1; Prkca, protein kinase C; Stim1, stromal interaction molecule 1. c, Visualization of gene expression heterogeneity in scRNA-seq data of 16,634 Purkinje cells as described by Kozareva et al. (2021). UMAP dimension reduction showing original authors’ identified PC clusters. Aldoc and zebrin are equivalent. d, UMAP plot showing the region of the cerebellum that the cells were sampled from, demonstrating the lack of full alignment between molecularly defined cell-type and lobular identity. e, Lobules IV/V, lobule X, and the flocculus are separated out from d, demonstrating that all three regions fall in different clusters, with some overlap. Also see Extended Data Figure 6-1.