Figure 1.

Synaptic and intrinsic properties of 4-week-old adult-born granule cells vs. mature granule cells.

Behavioral data suggest a critical period for 4-week-old adult-born granule cells (ABGCs) in memory processing. During this period, ABGCs display increased amplitude and decreased induction threshold for long-term potentiation. Also, input-resistance is around two-fold higher than in mature granule cells, making them more efficient in transducing ionic currents into membrane depolarization. In addition, as the intracellular Cl^- concentration is increased, γ-aminobutyric acid currents may produce shunting rather than hyperpolarizing inhibition of ABGCs. These properties afford ABGCs with a transient hyper-plastic period that may enhance their incorporation into memory circuits.