Neurogenesis persists in the dentate gyrus throughout life, but declines sharply with aging. We have recently shown that 40 Hz audiovisual stimulation (AuViS) enhances activity in the aged dentate gyrus and promotes neurogenesis in middle-aged mice. These effects may be related with changes within the neurogenic niche, yet the underlying cellular and molecular mechanisms remain unclear. We hypothesized that AuViS-induced cellular modifications are driven by transcriptional changes in the aged neurogenic niche. To test this idea, we performed single-nuclei RNA sequencing of the dentate gyrus from 8-month-old mice exposed to 6 weeks of AuViS or control conditions. Notably, the most significant change was the transcriptional upregulation of tight junction–related genes such as Cldn5 in endothelial cells, suggesting enhanced blood–brain barrier (BBB) integrity. In contrast, neuronal populations displayed only subtle changes in gene expression. These results reveal that AuViS elicits cell type-specific transcriptional responses and point to BBB remodeling as a potential mechanism contributing to enhanced neurogenesis in the aged dentate gyrus.