Fear is an emotional response to danger that is highly conserved throughout evolution because it is critical for survival. Accordingly, episodic memory for fearful locations is widely studied using contextual fear conditioning, a hippocampus-dependent task (Kim and Fanselow, 1992; Phillips and LeDoux, 1992). The hippocampus has been implicated in episodic emotional memory and is thought to integrate emotional stimuli within a spatial framework. Physiological evidence supporting the role of the hippocampus in contextual fear indicates that pyramidal cells in this region, which fire in specific locations as an animal moves through an environment, shift their preferred firing locations shortly after the presentation of an aversive stimulus (Moita et al., 2004). However, the long-term physiological mechanisms through which emotional memories are encoded by the hippocampus are unknown. Here we show that during and directly after a fearful experience, new hippocampal representations are established and persist in the long term. We recorded from the same place cells in mouse hippocampal area CA1 over several days during predator odor contextual fear conditioning and found that a subset of cells changed their preferred firing locations in response to the fearful stimulus. Furthermore, the newly formed representations of the fearful context stabilized in the long term. Our results demonstrate that place cells respond to the presence of an aversive stimulus, modify their firing patterns during emotional learning, and stabilize a long-term spatial representation in response to a fearful encounter. The persistent nature of these representations may contribute to the enduring quality of emotional memories.

This study aimed to test a structural model to examine the protective role of psychosocial variables, such as social support, emotional intelligence and their interaction, on the cognitive dimension of subjective positive well-being (life satisfaction) and negative well-being (depression) in Moroccan adolescents. The participants consisted of 1277 students (571 men, 694 women and 12 missing values) with a mean age of 16.15 years ( SD = 2.22; range = 9 to 23) who attended 26 public schools in different territories of Morocco. These students were in secondary education ( n = 893) and high school ( n = 378) (6 missing values). The scales for measuring the variables of interest had to be adapted and validated as a previous step for the further proposal of a model of relations. Statistical analyses were conducted using structural equation modeling (SEM) to test the proposed model. The model that optimally adjusted the data confirmed the protective role of social support in the well-being of Moroccan adolescents. Consistent with previous studies, social support was directly related to well-being. However, it also modulated levels of satisfaction with life. Likewise, the inclusion of emotional intelligence as an additional protective factor contributed to the explanation of the well-being mechanisms in adolescents. In addition to direct associations with the levels of social support, satisfaction with life and depression (negative in the latter case), emotional intelligence participated in a complex chain affecting life satisfaction and life satisfaction affecting depression. Moreover, the interaction of emotional intelligence with social support was confirmed to determine levels of life satisfaction in adolescents. Specifically, social support multiplied the effects of the relationship between satisfaction with life and emotional intelligence in cases of moderate and high levels in Moroccan adolescents. This study fills a gap in the literature by adapting and further analyzing several scales with Moroccan samples of adolescents and by proposing and verifying a relational model that can help researchers and teachers to more precisely clarify these relations according to their context. The enhancement of protective factors, such as social support and emotional intelligence, will promote healthy youth development, thus creating healthier societies in the future.

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Human participants were trained in a trial-by-trial contingency judgements task in which they had to predict the probability of an outcome (diarrhoea) following different cues (food names) in different contexts (restaurants). Cue P was paired with the outcome on half of the trials (partial reinforcement), while cue C was paired with the outcome on all the trials (continuous reinforcement), both cues in Context A. Test was conducted in both Context A and a different but equally familiar context (B). Context change decreased judgements to C, but not to P (Experiment 1). This effect was found only in the cue trained in the context where a different cue was partially reinforced (Experiment 2). Context switch effects disappeared when different cues received partial reinforcement in both contexts of training (Experiment 3). The implications of these results for an explanation of context switch effects in terms of ambiguity in the meaning of the cues prompting attention to the context (e.g., Bouton, 1997) are discussed.

The extinction of learned fear is a hippocampus-dependent process thought to embody new learning rather than erasure of the original fear memory, although it is unknown how these competing contextual memories are represented in the hippocampus. We previously demonstrated that contextual fear conditioning results in hippocampal place cell remapping and long-term stabilization of novel representations. Here we report that extinction learning also induces place cell remapping in C57BL/6 mice. Specifically, we observed cells that preferentially remapped during different stages of learning. While some cells remapped in both fear conditioning and extinction, others responded predominantly during extinction, which may serve to modify previous representations as well as encode new safe associations. Additionally, we found cells that remapped primarily during fear conditioning, which could facilitate reacquisition of the original fear association. Moreover, we also observed cells that were stable throughout learning, which may serve to encode the static aspects of the environment. The short-term remapping observed during extinction was not found in animals that did not undergo fear conditioning, or when extinction was conducted outside of the conditioning context. Finally, conditioning and extinction produced an increase in spike phase locking to the theta and gamma frequencies. However, the degree of remapping seen during conditioning and extinction only correlated with gamma synchronization. Our results suggest that the extinction learning is a complex process that involves both modification of pre-existing memories and formation of new ones, and these traces coexist within the same hippocampal representation.

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Highlights d Sleep deprivation improves memory in old mice but worsens it in young ones d Sleep deprivation decreases hippocampal flexibility and spindle counts in young mice d Increased spindle counts are associated with improved memory in old mice d Sleep deprivation improves the quality of hippocampal representations in old mice