Adult Neurogenesis: Cellular Mechanisms, Regulatory Pathways, and Therapeutic Prospects in Neurodegenerative Diseases

Adult neurogenesis, the generation of new neurons within the mature brain, remains an active area of investigation and debate. Robust evidence from animal models demonstrates that newly generated neurons contribute to learning, memory, and neural plasticity, and that disruption of this process accompanies neurodegenerative conditions such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. In contrast, evidence for persistent and functionally relevant neurogenesis in the adult human brain is more limited and heterogeneous. Recent studies have advanced understanding of the intrinsic and extrinsic mechanisms regulating adult neurogenesis, including transcriptional, epigenetic, and signaling pathways, as well as hormonal and environmental influences. These findings have prompted interest in therapeutic strategies to enhance neurogenesis through pharmacological agents, gene- and stem-cell-based approaches, and lifestyle interventions such as physical exercise and cognitive training. This review critically synthesizes current knowledge of adult neurogenesis, delineates key controversies regarding its persistence and functional significance in humans, and highlights translational challenges that must be addressed before neurogenesis can be reliably harnessed for brain repair.