Operant behavior in Zif268 mutant mice under progressive ratio schedule.

Groups of homozygous (KO, n = 11) and heterozygous (Het, n = 16) Zif268 mutant mice and their wild type (WT, n = 18) littermates were trained under progressive ratio (or PR) schedule. a) Breaking point measured during 2-h session under progressive ratio schedule. Both homozygous and heterozygous mutant mice show reduced breaking points when compared to wild type controls. The results (means ± SEM) are analyzed using one-way ANOVA (see the F value in Results). Post hoc comparison (Bonferroni test): * p<0.05. b) Cumulative number of nose-pokes into the reinforced orifice during progressive ratio schedule session (2 h). Both homozygous and heterozygous mutant mice show a reduced activity on the reinforced hole as compared to wild type controls. At 2 h, data were analyzed with one-way ANOVA (see the F value in Results).