Learning related plasticity in the antennal lobe helps discrimination of similar floral odors

FERNANDEZ P; LOCATELLI F; YOSHIHIRO A; SMITH B

Colonia del Sacramento, Uruguay

Congreso; Ist Latin American Meeting of Chemical Ecology 2010; 2010

Latin American Society for Chemical Ecology

Learning related plasticity in the antennal lobe helps discrimination of similar floral odors Patricia C. Fernandez2, Fernando F. Locatelli3, Anna Yoshihiro1, Brian H Smith1 1 School of Life Sciences, Arizona State University, AZ, USA 2  EEA Delta del Paraná, INTA. Paraná de las Palmas y canal Comas, Campana, Buenos Aires and Cátedra de Biomoléculas, Facultad de Agronomía, UBA. Av. San Martin 4453, CABA, Argentina 3.  IFIByNE, CONICET, Pab II, Ciudad Universitaria, CABA, Argentina. Flower odors are highly variable combinations of several volatile components. No two flowers smell exactly alike, even examples from the same species and cultivar. Pollinators must therefore establish if a newly encountered flower is similar enough to a previous rewarded one, turning foraging decisions into a fine tuned generalization-discrimination task. Sensory and neural systems must provide mechanisms for very precise odor recognition, allowing perceptual stability (i.e. generalization to prevent all experiences from being independent and novel) [1]. We hypothesize that experience with odors tunes sensory processing and thereby improves odor recognition and classification of newly encountered flowers [2]. In the present work we designed artificial floral blends that mimic the components, proportions and variability of 2 natural varieties of snapdragon flowers. All designed blends share the same components. But they can be differentiated based on the relative concentration of the components, which were more similar within than between cultivars. We trained restrained honey bees using the proboscis extension response paradigm (PER). Bees were differentially conditioned using examples of both cultivars. After training we tested the ability to recognize a new example from each cultivar. The duration of PER was lower and the latency longer when an example of the non-rewarded cultivar was offered to the trained bee. Odor induced activity patterns were measured in Projection Neurons of the Antennal Lobe by calcium imaging. Consistent with behavior, results suggest that the neural network in the AL is tuned via differential conditioning to decorrelate mixtures representing different floral varieties. Experience-dependent plasticity at the level of the Antennal Lobe may help animals categorize a newly flower as belonging to a class related to reinforcement. This kind of mechanism may allow bees a quick adaptation to a different and constantly changing environment.