Extinction memory in the crab Chasmagnathus: recovery protocols and effects of multi-trial extinction training

HEPP, Y; PÉREZ-CUESTA, LM; MALDONADO, H; PEDREIRA, ME

Animal Cognition

Springer-Verlag

Año: 2009

1435-9448

A decline in the frequency or intensity of aconditioned behavior following the withdrawal of thereinforcement is called experimental extinction. However,the experimental manipulation necessary to trigger memoryreconsolidation or extinction is to expose the animal to theconditioned stimulus in the absence of reinforcement.Recovery protocols were used to reveal which of these twoprocesses was developed. By using the crab contextualmemory model (a visual danger stimulus associated withthe training context), we investigated the dynamics ofextinction memory in Chasmagnathus. Here, we reveal thepresence of three recovery protocols that restore the originalmemory: the old memory comes back 4 days after theextinction training, or when a weak training is administeredlater, or once the VDS is presented in a novel context 24 hafter the extinction session. Another objective was to evaluatewhether the administration of multi-trial extinctiontraining could trigger an extinction memory in Chasmagnathus.The results evince that the extinction memory appearsonly when the total re-exposure time is around 90 min independentlyof the number of trials employed to accumulateit. Thus, it is feasible that the mechanisms described for thecase of the extinction memory acquired through a singletraining trial are valid for multi-trial extinction protocols.Finally, these results are in agreement with those reportsobtained with models phylogenetically far apart from thecrab. Behind this attempt is the idea that in the domain ofstudies on memory, some principles of behavior organizationand basic mechanisms have universal validity.