Chronic Stress and Adult Hippocampal Neurogenesis: Unraveling the Complex Interplay

The hippocampus in mammalian brain is one of the first regions experimentally demonstrated for adult neurogenesis, which is the evidence overturned Cajals hypothesis. Adult hippocampal neurogenesis (AHN) involves the incorporation of newly generated neurons into the innermost granule cell layer (GCL) of the dentate gyrus, and the integration of new neurons into the existing hippocampal circuitry is associated with increased resilience to stress. However, chronic stress, as an upstream factor that can be controlled by neurogenesis, also have counterproductive effects on adult hippocampal neurogenesis. Considering the current trend of increasing social chronic stressors and soaring incidence of major depressive disorder (MDD), analyzing the complex interactions between chronic stress and AHN is particularly important.