Manuel M. Ramos Alvarez

Long-term stabilization of place cell remapping produced by a fearful experience

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.

Extinction of Learned Fear Induces Hippocampal Place Cell Remapping

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.

Self-Efficacy Expectations in Teacher Trainees and the Perceived Role of Schools and Their Physical Education Department in the Educational Treatment of Overweight Students.

This study is about the relation between self-efficacy expectations and the attitude towards child and youth obesity, as well as the role of the school in this matter. A questionnaire was given to a sample of 436 trainee physical education teachers from eight universities in Andalusia (Spain). The questionnaire was a version of Teaching Self-Efficacy in Higher Education (Prieto, 2007) and of Perceptions of Youth Obesity among Physical Educators (Greenleaf and Weiller, 2005). The results indicated that those trainees who possessed a higher level of perceived self-efficacy for the assessment of not only their own teaching, but also of the knowledge acquired by overweight students and of school intervention in their learning process, tended to show more favourable attitudes towards the educational treatment of child and youth obesity, and towards obese students’ fitness and healthcare. The trainees with a perceived higher level of self-efficacy for the assessment of the progress made by overweight students and with a more favourable disposition towards revising their teaching practice tended to show a more negative attitude towards obese people.