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

A decline in the frequency or intensity of a conditioned behavior following the withdrawal of the reinforcement is called experimental extinction. However, the experimental manipulation necessary to trigger memory reconsolidation or extinction is to expose the animal to the conditioned stimulus in the absence of reinforcement. Recovery protocols were used to reveal which of these two processes was developed. By using the crab contextual memory model (a visual danger stimulus associated with the training context), we investigated the dynamics of extinction memory in Chasmagnathus. Here, we reveal the presence of three recovery protocols that restore the original memory: the old memory comes back 4 days after the extinction training, or when a weak training is administered later, or once the VDS is presented in a novel context 24 h after the extinction session. Another objective was to evaluate whether the administration of multi-trial extinction training could trigger an extinction memory in Chasmagnathus. The results evince that the extinction memory appears only when the total re-exposure time is around 90 min independently of the number of trials employed to accumulate it. Thus, it is feasible that the mechanisms described for the case of the extinction memory acquired through a single training trial are valid for multi-trial extinction protocols. Finally, these results are in agreement with those reports obtained with models phylogenetically far apart from the crab. Behind this attempt is the idea that in the domain of studies on memory, some principles of behavior organization and basic mechanisms have universal validity.     

Psychological characteristics of infertile couples: can they predict pregnancy and treatment persistence?

The paper describes an exploratory study of the relative importance of different psychological variables for the prediction of (a) pregnancies and (b) treatment continuation in a sample of 140 couples seeking specialized infertility treatment one year after their first contact with an infertility clinic. The couples filled out questionnaires dealing with psychological and interpersonal functioning, marital and life satisfaction, child-related attitudes, causal attribution of infertility and general expectations towards the treatment. It could be shown that the psychological variables explain a relatively small amount of the variance of the pregnancy criterion. Nevertheless, there were some indications supporting the hypothesis that psychological complaints can be seen as a ‘risk factor’ associated with a lower pregnancy rate. Couples who had terminated treatment after one year indicated a higher amount of psychological and interpersonal complaints (females) as well as partner problems (males and females), and a dominance of internal attributions of the fertility problem. This result—which might help to develop strategies for counselling couples making use of the new reproductive technologies—highlights the importance of attribution and cognitive appraisal in coping with infertility. © 1998 John Wiley & Sons, Ltd.     

Memory is not extinguished along with CS presentation but within a few seconds after CS-offset

Prior work with the crab's contextual memory model showed that CS-US conditioned animals undergoing an unreinforced CS presentation would either reconsolidate or extinguish the CS-US memory, depending on the length of the reexposure to the CS. Either memory process is only triggered once the CS is terminated. Based on these results, the following questions are raised. First, when is extinction memory acquired, if not along extinction training, and how long does it take? Second, can acquisition and consolidation of extinction memory be pharmacologically dissected? Here we address these questions performing three series of experiments: a first one aimed to study systematically the relationship between extinction and increasing periods of unreinforced CS presentations, a second one to determine the time boundaries of the extinction memory acquisition, and the third one to assay the requirement for protein synthesis and NMDA-like receptors of acquisition and consolidation of extinction memory. Our results confirm that it is CS-offset and not the mere retrieval (CS-onset) that triggers acquisition of extinction memory and that it is completed in less than 45 sec after CS-offset. In addition, protein synthesis is required for consolidation but not for acquisition of this memory and, conversely, NMDA-like receptor activity is required for its acquisition but not for its consolidation. Finally, we offer an interpretative scheme of our results and we discuss to what extent it could apply to multitrial extinction.     

Affective state and event-based prospective memory

Event-based prospective memory tasks require the realisation of a delayed intention at the occurrence of a specific target event. The present research investigates how performance in this kind of prospective memory task is influenced by the current affective state. By manipulating participants' mood during intention realisation we tested two competing models of mood effects on memory (i.e., a capacity consuming account and a processing style account). Furthermore, we manipulated the valence of the target event to investigate mood-congruency effects in prospective memory. No evidence was found for a mood-congruency effect, but the results showed that prospective memory performance increased with a sad mood. This effect is consistent with recent theories on mood-dependent processing-style regulation, postulating that a sad mood produces a more analytic and detailed processing style whereas a happy mood produces a more global and less detailed processing style.