Learning tunes spatio-temporal patterns in early olfactory coding

LOCATELLI F; FERNANDEZ P; YOSHIHIRO A; SMITH B

Huerta Grande, Cordoba, Argentina

Congreso; Primera Reunion Conjunta de Neurociencias; 2009

Sociedad Argentina de Neurociencias y Taller de Neurociencias

Learning tunes spatio-temporal patterns in early olfactory coding. Fernando F. Locatelli, Patricia C. Fernandez,  Anna Yoshihiro and  Brian H Smith. School of Life Sciences, Arizona State University, USA. The olfactory system is commonly based on a large number of generalist receptors whose combinatorial activation guarantees an almost infinite number of percepts. However, an individual animal does never encounter such wide range of stimuli. Instead, it has to optimize its sensory system to gain discrimination of the odors that are present in the reduced environment in which it exists. We use honey bees and their capacity for olfactory learning to address how experience shapes stimuli processing in the antennal lobe. Honey bee foragers learn about floral odors that are rewarded and also learn to ignore flowers that have no predictive value. They must establish if any new encountered flower is similar to a previous rewarded one or to a non-rewarded one, turning foraging decision into a fine tuned generalization-discrimination task. We performed behavioral experiments and calcium imaging of odor driven activity in the antennal lobe to study if learning modifies the perceptual boundaries used to classify a floral perfume within a rewarded or a non-rewarded flower category. We designed odor blends that mimic the variability within and between two real cultivars of snapdragon flowers. All blends could be differentiated based on the relative concentration of the components, which was more similar within cultivar than between them. Bees were trained to either generalize or differentiate between both cultivars. Odor representation was measured in projection neurons of the antennal lobe. Antennal lobe activity was modified by learning in a way that odor representations of rewarded and non rewarded flowers are more different. These data suggest that learning tunes the AL such that relevant odors become more discriminable.