Neural basis of latent inhibition to odors in honeybees

LOCATELLI F; GALIZIA G; SMITH B

Sarasota, FL, EEUU

Congreso; Association for Chemoreception Sciences (AChemS); 2007

Association for Chemoreception Sciences (AChemS)

Neural basis of latent inhibition to odors in honeybees Fernando F. Locatelli, C. Giovanni Galizia, Brian H. Smith School of Life Sciences, Arizona State University, Tempe, AZ, USA Lehrstuhl für Neurobiologie, Universität Konstanz, Germany Honeybee foragers learn about rewarded floral odors. They also must learn to ignore odors that have no predictive value. This form of learning, called Latent Inhibition (LI), is induced by unrewarded exposure to an odor. LI is revealed by reduced learning performance when the preexposed odor is subsequently paired with reinforcement. We used calcium imaging to evaluate if exposure to an odor in a way that induces behavioral LI affects the neural representation of that odor in the primary olfactory neuropil, the antennal lobe (AL). AL projection neurons were labeled with the calcium sensor dye Fura2. Odor-evoked activity was measured for two pure odors and the binary mixture before and after preexposure to one of the pure odors. Analysis based on intensity and spatial distribution of the evoked activity shows odor specific activity patterns characterized by partially overlapping groups of glomeruli. Binary mixtures evoked activity in the same glomeruli as the single odors. Induction of LI produced an odor-specific reduction in activity. This effect was not evident in all animals, which is consistent with genetic variation in expression of LI. The reduction in response was specific to the preexposed odor, so it was not due to a generalized reduction of activity in the AL. After LI induction the activity evoked by the mixture is less similar to the preexposed odor and shifts toward the pattern for the other odor. We are currently investigating modulatory pathways that mediate this form of plasticity in the AL. Supported by DC007997 from NIH-NIDCD.