Single-cell transcriptomics reveals a pallial GABAergic neurogenic lineage in the pallium of adult zebrafish

The adult zebrafish pallium is a highly active neurogenic niche, yet adult pallial neuro-genesis has been assumed to generate predominantly glutamatergic neurons. Previous in vivo EdU labeling revealed that ~3% of adult-born pallial neurons adopt a GABAergic phenotype, a proportion that increases approximately fourfold after cognitive training. To test whether pallial neural stem cells (NSCs) generate GABAergic lineages, we analyzed a published scRNA-seq dataset of the adult zebrafish telencephalon. After quality filtering and clustering, we identified 16,321 cells across 15 groups, including 11,130 neuronal-lineage cells. Integrated annotation revealed GABAergic immature neu-rons with pallial identity, co-expressing GABAergic genes (dlx1a, dlx2a, dlx5a, gad1a/b, gad2) and pallial markers (cbln1, nr2f2, sox4a, emx2/3). Their molecular signature ena-bled detection of GABAergic-like pallial neuroblasts (~4% of pallial neuroblasts) and NSCs with GABAergic features (~5% of NSCs). These NSCs expressed pallial markers (emx2/3, wnt3a) alongside GABAergic determinants (nkx2.1, lhx5, zfhx3/4) and were tran-scriptionally distinct from pallial glutamatergic and subpallial GABAergic NSCs. Together, our results support a local GABAergic neurogenic trajectory in the adult zebrafish pallium and reveal previously underappreciated flexibility in adult NSC fate output.