Figure 2.

Critical periods for spatial learning induced changes in immature cell survival in the dentate gyrus. Spatial learning does not impact the survival of immature neurons that are 1–5 days old at the time of learning. Survival of immature neurons that are 6–10 days old during training is selectively enhanced [although this can depend on task difficulty (Epp and Galea, 2009) and quality of learning (Epp et al., 2007; Sisti et al., 2007)]. Survival of immature neurons that are 15–20 days old at the time of learning is decreased. This effect cannot be detected if animals are perfused the day following training but can be observed if histological examination is delayed until day 20 following a probe trial 90 min before perfusion. Collected from findings from Epp et al. (2007 and 2011a). Described changes in neurogenesis are in comparison to rats trained on a cued version of the task.