Aversive and appetitive memories compete during retrieval in the crab Neohelice

AYELÉN NALLY; MARTÍN KLAPPENBACH; FERNANDO LOCATELLI

Montevideo

Congreso; XII Congress of the International Society for Neuroethology; 2016

Unlike experimentally controlled situations, animals in nature might be exposed to contradictory information. Situations or places might simultaneously predict desired and undesired consequences. However, at some point the situation has to be categorized as appetitive or aversive, in order to decide if repeat or avoid it in the future. How contradictory information is integrated and how it affects learning and memory has not been yet extensively studied. In the present work we took advantage of the well described aversive and appetitive learning paradigms in the crab Neohelice to explore learning after simultaneous appetitive and aversive experiences associated to the same context. First, we found that two parallel memory traces are formed after simultaneous appetitive and aversive training. Second, we found that the probabilities to express no, one or both learned behaviors depend on the balance between the relative strength of the aversive and appetitive unconditioned stimuli, thus revealing a mutual interference under certain conditions. Finally, we found that the mentioned interferences do not occur during learning or memory formation, rather during memory retrieval. These results suggest that both memories could be actually available to be retrieved upon presentation of the conditioned stimulus, but the access of memory to behavior might be modulated based on specific demands at the moment of retrieval.