Figure 2

Associative olfactory task. (a) Mice were trained to discriminate between two odors using an associative olfactory task in which the + odor but not the -odor was paired with sugar. (b) The + and -odors were composed of increasingly similar binary mixtures of R-carvone and S-carvone. (c) During training, mice spent more time digging at the + odor compared to the -odor regardless of odor similarity (100:0: n = 10; 90:10: n = 9; 80:20: n = 8; 70:30: n = 8; 60:40: n = 9; 50:50: n = 8). (d) During a probe test given 24 hours after training, mice spent more time digging at the + odor compared to the -odor when the odors were relatively distinct (100:0, 90:10, 80:20) but not when the odors were relatively similar (70:30, 60:40) or identical (50:50). (e) Mice had discrimination indices above chance level only when the odors were relatively distinct (100:0, 90:10, 80:20).