Prior extinction increases acquisition context specificity in human predictive learning.

One experiment evaluated the effect of extinction on the context dependence of non-extinguished information in a situation in which physical (images), rather than predominantly verbal, contexts were used in human predictive learning. Participants received training in which different foods (Cues) were associated with the presence or the absence of gastric illness (outcome) in customers of different restaurants (contexts). One cue was associated with the gastric illness while a different cue was either extinguished or not between groups. A change in the context at test led to a general decrease in both predictive judgments and the speed of responding to the non-extinguished cue. However, these decreases were greater when training was conducted during extinction of the different cue demonstrating the extinction makes acquisition context-specific (EMACS) effect. Results are contrasted with failures to find the effect in other reports and discussed in terms of extinction leading to an allocation of attentional resources to the context, facilitating the context dependence of information.

Testing a cue outside the training context increases attention to the contexts and impairs performance in human predictive learning.

One experiment in human predictive learning explored the impact of a context change on attention to contexts and predictive ratings controlled by the cue. In Context A: cue X was paired with an outcome four times, while cue Y was presented without an outcome four times in Context B:. In both contexts filler cues were presented without the outcome. During the test, target cues X and Y were presented either in the context where they were trained, or in the alternative context. With the context change expectation of the outcome X, expressed as predictive ratings, decreased in the presence of X and increased in the presence of Y. Looking at the contexts, expressed as a percentage of the overall gaze dwell time on a trial, was high across the four training trials, and increased with the context change. Results suggest that the presentation of unexpected information leads to increases in attention to contextual cues. Implications for contextual control of behavior are discussed.

Attentional perspectives on context-dependence of information retrieval

Attention has been traditionally understood as an important factor on acquiring new information. A review of the literature suggests that attention, specifically attention to the contexts, also plays a relevant role on information retrieval. It also shows that attention to the contexts is modulated by the ambiguity of the situation, and the informative value contexts have. The virtues and limitations of different attentional theories of learning applied to the explanation of the effects of context change on retrieval of the information are discussed. This analysis uncovers the weaknesses of current research on context processing that should be corrected by future research: The need of independent measures of attention to the contexts, the evaluation of the mechanisms of contextual control, and the possibility of taking an evolutionary perspective on the effects of context change (AU)

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Attention to irrelevant contexts decreases as training increases: Evidence from eye-fixations in a human predictive learning task.

Participants were trained in a human predictive learning task in which they had to predict whether the ingestion of a given food (cue) by the imaginary customer of an imaginary restaurant (context) was followed by gastric malaise (outcome). One food was always followed by gastric malaise in one of the contexts, while other foods were not followed by gastric malaise in the same, or in an alternative context. Predictive responses and eye-fixations were recorded throughout the 48 training trials with each cue involved in the task. In agreement with the predictions of the Attentional Theory of Context Processing, attention to the contexts measured through eye-fixations decreased while attention to the cues increased as training progressed. The results of this study give support to the idea that contexts are actively processed at the beginning of acquisition, and that this processing decreases as training increases.

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.

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.

Context-outcome associations underlie context-switch effects after partial reinforcement in human predictive learning

El valor predictivo que se asigna a claves reforzadas de forma continua se ve afectado por el cambio de contexto cuando éstas se entrenan en un contexto en el que otra clave diferente recibe reforzamiento parcial. Se llevó a cabo un experimento con el objetivo de explorar el mecanismo que subyace a este efecto de cambio de contexto. Se entrenó a participantes humanos en una situación de aprendizaje predictivo en la que una clave recibía reforzamiento parcial mientras que una clave objetivo (C1) recibía reforzamiento continuo en el contexto A y una segunda clave objetivo (U2) no era reforzada en el contexto B. Los participantes del grupo Parcial-Uno no recibieron reforzamiento parcial en B, mientras que los participantes del grupo Parcial-Ambos recibieron el mismo entrenamiento que en el contexto A, pero con claves distintas. Cuando las claves objetivo se probaron en el grupo Parcial-Uno, se observó mayor respuesta en el contexto A que en el contexto B, aunque las diferencias fueron menores ante la clave U2 que ante C1. No se encontraron diferencias entre contextos en el grupo Parcial-Ambos. Estos resultados están en consonancia con la hipótesis de que el cambio de contexto tras el reforzamiento parcial se debe principalmente a la formación de asociaciones contexto-consecuencia, aunque la diferencia entre el tamaño del efecto sobre la clave reforzada y no reforzada sugiere que también podría estar implicado un mecanismo modulador en estos efectos de cambios de contexto(AU)

Predictive value for continuously reinforced cues is affected by context changes when they are trained within a context in which a different cue undergoes partial reinforcement. An experiment was conducted with the goal of exploring the mechanisms underlying this context-switch effect. Human participants were trained in a predictive learning situation in which a cue received partial reinforcement while a target cue received continuous reinforcement in context A (C1) and another target cue was presented unreinforced in context B (U2). Participants in group Partial-One did not receive partial reinforcement in context B, while participants in group Partial-Both received the same training they received in context A, but with different cues. When target cues were tested in group Partial-One, greater responding in context A than in context B was found. Differences were smaller in cue U2 than in cue C1. No differences across contexts were found in group Partial-Both. These results are in agreement with the hypothesis that context-switch effects after partial reinforcement are mainly due to the formation of direct context-outcome associations, though the difference on the effect size on the reinforced and unreinforced cues suggests that a modulator mechanism may be also responsible for these context-switch effects(AU)

Partial reinforcement and context switch effects in human predictive learning.

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.

Revisión de la teoría de la recuperación de la información: ¿qué convierte a la información en dependiente del contexto? / Revision of Retrieval Theory of forgetting: what does make information context-specific?

Este artículo explora el papel del contexto en la recuperación de la información, centrándose en los efectos diferenciales que el cambio de contexto tiene sobre la adquisición y la información interferente. Proponemos una modificación de la teoría de la recuperación de la información basada en resultados recientes de nuestro laboratorio que sugieren que la dependencia contextual de la información no depende de sus características específicas, sino de las características concretas de la situación que llevan a los participantes a prestar atención al contexto. Una vez aparece algo en la situación que lleva a los participantes a prestar atención al contexto, toda la información aprendida parece convertirse en específica del contexto, independientemente de si es el primer o segundo significado de la clave. Se proponen las bases de esta teoría atencional del procesamiento contextual

The role of context in retrieval of the information is explored, focusing in the differentiae effects of context change on acquisition and interfering information. Retrieval theory has proposed that context changes affect a specific type of information, either inhibitory or second-learned, interfering information. We propose a modification of retrieval theory based on recent results in our laboratory that suggests that context-specificity does not depend on specific features of the information, but on specific features of the situation that lead participants to pay attention to the context. Once there is something in the situation that leads participants to pay attention to the context, all the information learned seems to become context specific, regardless of whether it is the first or the second meaning of the cue. The outlines of this attentional theory of context processing are proposed