Basal forebrain cholinergic circuits orchestrate diverse cell types in the adult dentate gyrus to support neural stem cell function and spatial memory

Dentate gyrus (DG) is a critical structure involved in spatial memory and adult neurogenesis, two distinct processes dynamically regulated by local circuits comprising diverse populations of DG cells. It remains unknown how these DG cells are orchestrated to regulate these distinct hippocampal functions. Here we report activation of a cholinergic circuit from the Diagonal Band of Broca to DG promotes quiescent radial neural stem cell (rNSC) activation and spatial memory. Furthermore, single-nucleus RNA-sequencing reveals broad transcriptomic changes across DG mature and adult-born cells in response to cholinergic-circuit activation. Notably, neuronal populations exhibit cholinergic-activity-induced molecular changes related to synaptic functions crucial for spatial memory; while rNSCs exhibit changes related to structural remodeling and neurogenic proliferation crucial for hippocampal neurogenesis. Electrophysiology and NicheNet analyses reveal granule cells, endothelial cells, and astrocytes as potential intermediaries for cholinergic regulation of rNSCs. Our findings reveal cell-type-specific signaling mechanisms underlying cholinergic regulation of distinct DG functions.