in rats. In the Morris water maze paradigm, rats show deficits in lasting retention of spatial information at least 4 weeks following ablation of hippocampal neurogenesis, but not before (Shors et al., 2002; Madsen et al., 2003; Snyder et al., 2005; Jessberger et al., 2009). In mice, the picture is less clear. Studies have shown deficits or no change in context fear conditioning and Morris water maze learning in mice of various strains, gender, and ages, from different time points following ablation (Raber et al., 2004; Rola et al., 2004; Saxe et al., 2006; Meshi et al., 2006; Imayoshi et al., 2008; Dupret et al., 2008; Zhang et al., 2008; Farioli-Vehhcioli et al., 2008; Deng et al, 2009; Garthe et al., 2009; Ko et al., 2009, Kitamura et al., 2009; Snyder et al., 2009a; Goodman et al., 2010), suggesting that strain, gender, and age-related differences in mice may exist in the time course for new neuron maturation and integration or reactions to different ablation techniques.
