Fig. 3.

Pgf^−/− mouse performance on the novel object recognition (NOR) test. On the NOR test, Pgf^+/+ but not Pgf^−/− mice spent less time exploring the objects during the choice phase compared with the sample phase, although there was no difference between genotypes in either phase (A). Both Pgf^+/+ and Pgf^−/− mice made fewer visits to the objects during the choice phase compared with the sample phase with no significant difference between genotypes in either phase (B). There was no significant difference in time spent exploring objects (C) or number of visits to the objects (D) over the entire NOR. In the choice phase, Pgf^−/− mice were able to differentiate between the novel object and familiar objects and spent more time exploring the novel object (E). Correspondingly, Pgf^−/− mice exhibited greater preference for the novel object compared with Pgf^+/+ mice as measured by the percent of total time spent exploring the novel object (F). Each mouse completed three 10 min trials. In the first trial, the arena was empty. In the second trial, two identical objects were present for the sample phase. In the third trial, one familiar object and one novel object were present for the choice phase. Data were analyzed with repeated-measures two-way ANOVA, unpaired, two-tailed t-tests, or Mann-Whitney tests as appropriate. Graphs show values for individual mice in the sample and choice phases (A, B, E), or means ± SD (C, D, F). Circles represent Pgf^+/+ mice, while squares represent Pgf^−/− mice; n = 23 Pgf^+/+ and 20 Pgf^−/− male and female mice. *P < 0.05, ***P < 0.001, ****P < 0.0001.