Discrimination of odor mixtures: effects of stimulation time, composition and training protocol

FERNANDEZ P; LOCATELLI F; RENNEL N; DELEO G; SMITH B

Sarasota, FL, EEUU

Congreso; Association for Chemoreception Sciences (AChemS) Meeting 2007; 2007

Association for Chemoreception Sciences (AChemS)

 Discrimination of odor mixtures: effects of stimulation time, composition and training protocol Fernandez P., Rennell N., Deleo G., Locatelli F., Smith B. ASU, Department of Life Sciences, Tempe, AZ Recognition and discrimination of floral scents by honeybees is a good model for how animals learn about odors. After learning about the relationship between a complex, multicomponent floral odor and carbohydrate or protein rewards offered by flowers, odor recognition is affected by factors such as carbon chain length, functional group, chain shape and concentrations of the components. Recently, there has been considerable debate as to whether stimulation times affect detectability and discriminability of odors. In order to test this hypothesis, we used proboscis extension response conditioning to examine the degree of generalization and discrimination of different ratios of binary odor mixtures (1-hexanol and 2-octanone). We first conditioned bees to either 9:1 or 1:9 ratios. In this protocol, honeybees generalize broadly to all other tested ratios (9:1, 7:3, 5:5, 3:7, 1:9). Discrimination conditioning (9:1+ vs 1:9-) produced steeper decreases in response from the reinforced (+) to the non-reinforced (-) mixture. Reinforcement of 5:5 (+) vs 9:1 or 1:9 (-) produced a Peak Shift in the response away from the unreinforced mixture, indicating an interaction of positive and negative generalization gradients. We are currently evaluating how shortening stimulus duration affects discrimination via the interaction of these gradients. These data are also being correlated to neural activity patterns in the Antennal Lobes using calcium imaging. Supported by DC007997 from NIH-NIDCD.