Figure 2. Odor Learning and Discrimination Is Enhanced, but Odor Memory Is Reduced in GluR-B^ΔFB Mice.

(A) Schematic diagram depicting Cre-mediated ablation of loxP-flanked exon 11 of the GluR-B alleles.

(B and C) Nine GluR-B^ΔFB (red) and nine GluRB^2lox littermate controls (black) were trained for successive odor discrimination tasks on 1% AA versus 1% EB (400 trials), 0.4% Cin/0.6% Eu versus 0.6% Cin/0.4% Eu (400 trials) and 1% Pel versus 1% Val. GluR-B^ΔFB mice showed increased learning/discrimination compared with controls, both using the performance as measured by percentage of correct trials ([B]; group effect: F_1,16 = 6.55, p < 0.05) or the discrimination index (C), that is the maximal difference of the sampling pattern (see Materials and Methods and Figure 1D–1F; F_1,16 = 29.5, p < 10⁻⁴).

(D) Sampling difference for the last 100 trials of the mixture discrimination task (indicated with a black arrow in [C]) for all 18 individual mice. Note that the GluR-B^ΔFB mice show a consistently larger sampling difference.

(E) Olfactory memory performance for nine littermate controls (black) and nine GluR-B^ΔFB (red) mice. Olfactory memory was tested at the time indicated by the black bar in (C) by interleaving the Pel and Val trials with unrewarded AA and EB trials. AA, amylacetate; Cin, cineol; EB, ethylbutyrate; Eu, eugenol; Pel, pelargonic acid; Val, valeric acid.