Subjetive rather than absolute reward value determines long term memory formation in honey bees

MARÍA DE LOS MILAGROS AZCUETA; FERNANDO LOCATELLI; CATALINA MADARNAS; MARTÍN KLAPPENBACH

Mar del Plata

Congreso; XXXII Congreso Anual de Investigación en Neurociencias; 2017

The honey bee is a classical model for studying the neural bases of associative learning. The establishment of a protocol in which bees learn the association between an odor and a reward while they provide access for neural recordings has been critical to elucidate many of the neural pathways involved in olfactory learning. The training protocol is based on the proboscis extension response which at the beginning of training is elicited by touching the antennae with sucrose solution. During conditioning an odor is presented few seconds before the sucrose solution. After few paired trials, the bees extend the proboscis toward the odor anticipating the reward. Several works have shown that increasing sucrose concentration, reward volume, or the number trials, have a positive impact on learning and memory. Here we studied if the effectiveness of reward to elicit memory formation does depend on the absolute value of the reward or if it is affected by its subjective value, which can be manipulated based on the animal´s expectations. We found that positive and negative changes in the sucrose concentration of the reward used during the training, do have positive and negative consequences on long-term memory formation. In addition, we found that bees form short and long-term reward expectations that modulate how training induces long -term memory. The results are consistent with previous studies that analyzed the effect that different rewards have in memory in free flying bees.