Competing aversive and appetitive memory traces in the crab Neohelice and in honey bees

FERNANDO LOCATELLI; KLAPPEBACH MARTIN

Guaruja

Congreso; The IUSSI International Congress; 2018

The IUSSI International Congress

Competing aversive and appetitive memory traces in thecrab Neohelice and in honey bees Fernando Locatelli,Martin Klappenbach The neurobiology of learning andmemory has been mainly studied by focusing on exclusive aversive or appetitivelearning paradigms. However, real-life experiences involve in many cases stimulithat become predictors of both aversive and appetitive consequences. We studiedthe learning and memory processes after experiences that contain conflictinginformation, and evaluated at which extent animals are able to integrate this informationto ensure adaptive behavior. Initially we studied this phenomenonby using Neohelice crabs. We took advantage of two well described appetitiveand aversive learning paradigms and combined them in a single training session.We found that crabs build separate appetitive and aversive memories thatcompete during retrieval but not during acquisition. Which memory prevails depends on the balance between the strength of the aversiveand appetitive stimuli and on the motivational state of the animals duringretrieval. Later on we moved to honey beesand tested this phenomenon by using appetitive and aversive olfactoryconditioning of the proboscis extension response. First of all we developed atraining/testing protocol that allowed us to evidence aversive conditioningafter pairing an odor with a bitter solution. We found that in contrast toappetitive training, aversive conditioning induces memory formation that lasts24 but not 48 hours. Second, we trained animals in a differential conditioningprotocol in which an odor was paired with sugar and a second odor was pairedwith a bitter solution. We found that bees were able to form two independentmemories. Third, we performed an experiment in which after differentialconditioning, animals were tested with an odor mixture that contained theappetitive and the aversive conditioned odors. During test, animals behavedalternatively according to the appetitive or to the aversive odor depending ontheir satiation level. Thus, in honey bees as in crabs, appetitive and aversivememories seem to be stored independently and compete during retrieval.