a, Estimated relative density of visceral motor neurons along the rostral-caudal axis of the spinal cord based on Allen Spinal Cord Atlas10. Density functions are combined density estimates of marker genes for each cluster (see Methods). Clusters were grouped according to shape of density function, with clusters 3,7, and 10 clearly enriched in the sacral spinal cord. b, Validation of visceral spatial modeling from (a) via high-resolution in situ hybridization for Chat and visceral cluster markers (Piezo2, Cdh8, Creb5, Cpne4, Fbn2). Plots show number of motor neurons counted in the autonomic column, added across three counted slides in each region. Individual data points for total visceral motor neurons shown with filled circles, while marker gene-positive cell numbers shown with filled triangles. n = 2 (Piezo2, Cdh8, Creb5, Cpne4) or 5 (Fbn2) biologically independent replicates. Error bars are SEM. c, Average log-normalized expression of Rxfp1 and Nts across all visceral motor neuron clusters (labeled), overlaid on UMAP. d, Representative in situ hybridization against Chat/Fbn2/Rxfp1 in transverse sacral spinal cord shows coexpression in the autonomic column but not in the ventral horn (VH). n = 3 biologically independent animals. Scale bar=100 µm. e, Average log-normalized expression of Adra2a across all visceral clusters (labeled) shows that sporadic expression exists across populations, overlaid on UMAP. f, Representative in situ hybridization against Chat/Piezo2/Cdh8 in cholinergic cells around the central canal (CC). Scale bar=50 µm. n = 2 biologically independent animals. g, Average log-normalized expression of Gldn across all cells in spinal cord shows clear enrichment in partition cell cluster (arrowhead), overlaid on UMAP. h, Average log-normalized expression of Nrxn3 across cholinergic interneurons shows that Nrxn3 expression is limited to half of partition cells (arrowhead), overlaid on UMAP.