Schematic of the main conclusions from Kang et al. (2022) illustrating a maturational stage-dependent contribution of GCs to feedback inhibition after CCI. Mature GCs that are born during the early postnatal period (P8-P12; early-born) show a moderate increase in their contribution to feedback inhibition (indicated with a dashed line) compared with similarly aged GCs in sham-injured mice. Whereas GCs that are immature at the time of injury (adult-born pre-CCI) show a substantial increase in feedback inhibition (thick line), GCs born after injury (adult-born post-CCI) have a limited contribution to feedback inhibition that is not different from what would be expected from this population under normal conditions (dotted line). Blue represents ChR2-expressing GC from each cohort. Red represents PV⁺ basket cell. Gray represents a ChR2-negative mature GC used for electrophysiological recordings.