In contrast, when over 99% of doublecortin+ newborn neurons are eliminated in the dentate gyrus of transgenic mice expressing thymidine kinase under the control of GFAP promoter upon valganciclovir treatment, it does not alter the baseline level of anxiety (elevated-plus maze), yet causes depression (forced-swim and sucrose-preference tests) (Snyder et al., 2011). This evidence concerns the gene DCX and depressive disorder.