Where new neurons arise in the adult brain
Adult neurogenesis, the birth of new neurons after development, is concentrated in a specific niche: the subgranular zone of the dentate gyrus, part of the hippocampus. There, neural stem and progenitor cells divide, and a subset of their offspring mature, migrate a short distance, and integrate into existing circuits. The hippocampus is central to learning and memory, which is why this region attracts so much interest.
It is worth noting that the extent of human adult hippocampal neurogenesis is still scientifically debated, with studies reaching different conclusions; it appears to decline substantially with age.
Inputs proposed to raise or lower the rate
The pace of neurogenesis is not fixed. Aerobic exercise, learning, and enriched environments are among the most consistently reported promoters in animal studies, while chronic stress and elevated cortisol are reported to suppress it. Growth factors such as BDNF are part of the molecular machinery, and some supplements are marketed on the premise of supporting these signals.
Supplement claims here largely extrapolate from animal data, so they should be read cautiously. This is general educational information, not medical advice; consult a qualified professional regarding cognitive or neurological concerns.