Figure 6.

Summary of granule neuron maturation in the adult mouse hippocampus. a, Granule neuron maturation was separated into four stages. Stage A covers the initial events after the cell exits the cell cycle, including differentiation, polarization, migration, and the initial neurite outgrowth. Stage B involves dendritic and axonal growth. B1 and B2 are separated at the time when axon fibers first enter the CA3 area. The initiation of spine growth marks the beginning of stage C, and this stage covers the later dendritic and axonal growth. Stage D starts shortly after spine formation during stage C and continues for several months. DG, Dentate gyrus; HF, hippocampal fissure. b, Temporal map of morphogenetic events during the maturation of newborn granule neurons. The arrowheads indicate key events during early morphogenesis: the migration of axon fibers into the CA3 area and the initiation of spine genesis.