Neurogenesis is a process by which the brain forms new neurons and promotes the proliferation, survival, and differentiation of said neurons.
While neurogenesis occurs in low levels in adults, it is still a governing process in some regions of the brain. The hippocampus in particularly is largely mediated by neurogenesis even into adulthood. The hippocampus is the region of the brain responsible for memory consolidation, spatial navigation, and cognitive processing (particularly executive functions such as impulse control).
As such, it stands to reason that neurogenesis can be a powerful tool for enhancing cognition, and can be very effecting for improving long-term and episodic memory, as this is one of the primary functions of the hippocampus.
Neurogenesis can be enhanced through the use of nootropic substances, which typically do this by raising levels of the neurotrophins BDNF (Brain-Derived Neurotrophic Factor) and NGF (Nerve Growth Factor), two endogenously produced molecules in the brain which regulate neurogenesis.
While BDNF and NFG are not the only neurotrophins in the brain, most nootropics that promote neurogenesis have been shown to effect them almost exclusively. Some nootropics such as Semax appear to elevate BDNF levels quite significantly, which is a rather rare quality.
List of Nootropics for Neurogenesis: