Figure 3.

Calcium activity in the antennal lobe. (A) Total intensity of activation of the antennal lobe. Amplitudes are normalized to the global intensity of activation recorded for odors in the first trial, when bees are still naïve (0 level). Left: for learners, no difference was found between CS+ and CS− during conditioning trials (stimuli effect, p = NS). Right: the same lack of differentiation was observed for non-learners, but these bees exhibited a significant decrease of the total antennal lobe activation during conditioning trials (trial effect, ***p < 0.001). Learners did not exhibit such a decrease (trial effect, p = NS). (B) Number of activated glomeruli. To get rid of that different odors activate different numbers of glomeruli in naïve bees, we normalized the data to the number of glomeruli activated by each odor in the first trial (100%). Left: for learners no difference was found between the number of glomeruli activated by the CS+ and the CS− during conditioning trials (stimulus effect, p = NS). Right: for non-learners, there was also no difference between the number of glomeruli activated by the CS+ and the CS− during conditioning trials (stimulus effect, p = NS). Aversive conditioning does not modify global activity of the antennal lobe in a learning-dependent manner.