Fig. 2.

Spontaneous spatial novelty preference task. (a) GRM2/3^−/− mice showed reduced spatial novelty preference compared with WT animals. GRM2^−/− (b) and GRM3^−/− (c) mice did not differ from WT controls. Data shown are mean discrimination ratios for the time spent in the arms during the test phase [novel arm/(novel + other arm)] ± SEM. A discrimination ratio of 0.5 reflects chance performance. Asterisk indicates a statistically significant difference between groups (t-test at p < 0.05). n = 11 WT; n = 11 GRM2/3^−/−; n = 15 WT; n = 14 GRM2^−/−; n = 15 WT; n = 15 GRM3^−/−.