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We tested the validity of two alternative accounts of the Attentional Boost Effect (ABE) - the finding that words associated with to-be-responded targets are recognized better than words associated with to-be-ignored distractors. The distinctiveness hypothesis assumes that, during recognition, participants probe their memories for distinctive information confirming that a word was studied (e.g., "I remember having pressed the spacebar, so I must have studied the word"). This strategy cannot be used in a between-subjects condition in which participants cannot appreciate the differences between target - and distractor-paired words. In agreement, Experiments 1A and 1B found that the ABE was significant in a within-subjects design, whereas it was eliminated in a between-subjects design. On the other hand, the performance anticipation hypothesis assumes that, during the study phase, participants anticipate the need of responding to a subset of target-paired words: this would create a persistent performance anticipation that would prevent them from effectively encoding distractor-paired words. In contrast with this account, we found that, when blocks of five distractor trials were regularly alternated with blocks of five target trials in Experiment 2, recognition accuracy decreased linearly in both conditions. Overall, these results suggest that distinctiveness, but not performance anticipation, might underlie the ABE.

In the attentional boost effect (ABE), words or images encoded with to-be-responded targets are later recalled better than words or images encoded with to-be-ignored distractors. The ABE has been repeatedly demonstrated to improve item memory, whereas evidence concerning contextual memory is mixed, with studies showing both significant and null results. The present three experiments investigated whether the ABE could enhance contextual memory when using a recognition task that allowed participants to reinstate the original study context, by simultaneously manipulating the nature of the instructions provided at encoding. Participants studied a sequence of colored words paired with target (gray circles) or distractor (gray squares) stimuli, under the instructions to remember either the words and their colors (Exps. 1-2) or only the words (Exp. 3) and simultaneously press the space bar whenever a gray circle appeared on the screen. Then, after a brief interval, they were administered a modified recognition task involving two successive stages. First, participants were presented with two different words and had to decide which word was originally encoded; second, they were presented with five colored versions of the (correct) old words and had to remember the color in which they were studied. Results converged in showing that the ABE enhanced contextual memory, although the effect was more robust with intentional encoding instructions., (© 2022. The Psychonomic Society, Inc.)

The present study examined predictions of the early-phase-elevated-attention hypothesis of the attentional boost effect (ABE), which suggests that transient increases in attention at encoding, as instantiated in the ABE paradigm, should enhance the recognition of neutral and positive items (whose encoding is mostly based on controlled processes), while having small or null effects on the recognition of negative items (whose encoding is primarily based on automatic processes). Participants were presented a sequence of negative, neutral and positive stimuli (pictures in Experiment 1, words in Experiment 2) associated to target (red) squares, distractor (green) squares or no squares (baseline condition). They were told to attend to the pictures/words and simultaneously press the spacebar of the computer when a red square appeared. In a later recognition task, stimuli associated to target squares were recognised better than stimuli associated to distractor squares, replicating the standard ABE. More importantly, we also found that: (a) the memory enhancement following target detection occurred with all types of stimuli (neutral, negative and positive) and (b) the advantage of negative stimuli over neutral stimuli was intact in the DA condition. These findings suggest that the encoding of negative stimuli depends on both controlled (attention-dependent) and automatic (attention-independent) processes.

The present study reports 2 experiments examining the Attentional Boost Effect (ABE) in schizophrenic patients and matched healthy controls, using visual and verbal materials. The ABE refers to the surprising finding that, in a divided attention condition, images and words encoded with targets are remembered better than images and words encoded with distractors. Unlike controls (who showed the typical ABE), schizophrenic patients reported no memory advantage for stimuli presented together with targets in the divided attention condition. On the other hand, the interference effect on the recognition of stimuli presented with distractors was not exacerbated in patients (as compared with controls). In line with the dual-task interaction model proposed by Swallow and Jiang (2013), the absence of a significant facilitation indicates that schizophrenic patients have a deficit in the process of attentional enhancement triggered by target detection. A number of neural mechanisms potentially underlying this impairment are discussed, as well as implications for the characterization of the attentional deficits involved in schizophrenia., ((c) 2014 APA, all rights reserved.)

The highly conserved mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling cascade is involved in several intracellular processes ranging from cell differentiation to proliferation, as well as in synaptic plasticity. In the last two decades, the role of MAPK/ERK in long-term memory formation in mammals, particularly in fear-related memories, has been extensively investigated. In this review we describe knowledge advancement on the role of MAPK/ERK in orchestrating the intracellular processes that lead to the consolidation, reconsolidation and extinction of fear memories. In doing so, we report studies in which the specific role of MAP/ERK in switching from memory formation to memory erasure has been suggested. The possibility to target MAPK/ERK in developing and/or refining pharmacological approaches to treat psychiatric disorders in which fear regulation is defective has also been envisaged., (Copyright © 2013 Elsevier Inc. All rights reserved.)

RNA-Induced Silencing Complex (RISC) mediates post-transcriptional control of gene expression and contains Argonaute 2 (AGO2) protein as a central effector of cleavage or inhibition of mRNA translation. In the brain, the RISC pathway is involved in neuronal functions, such as synaptic development and local protein synthesis, which are potentially critical for memory. In this study, we examined the role of RISC in memory formation in rodents, by silencing AGO2 expression in dorsal hippocampus of C57BL/6 mice and submitting animals to hippocampus-related tasks. One week after surgery, AGO2 downregulation impaired both short-term and long-term contextual fear memories. Conversely, no long-lasting effects were observed three weeks after surgery, when AGO2 levels were re-established. These results show that altered RISC activity severely affects learning and memory processes in rodents.

Neurogenesis in the dentate gyrus of the adult hippocampus has been implicated in neural plasticity and memory, but the molecular mechanisms controlling the proliferation and differentiation of newborn neurons and their integration into the synaptic circuitry are still largely unknown. To investigate this issue, we have analyzed the adult hippocampal neurogenesis in a PC3/Tis21-null mouse model. PC3/Tis21 is a transcriptional co-factor endowed with antiproliferative and prodifferentiative properties; indeed, its upregulation in neural progenitors has been shown to induce exit from cell cycle and differentiation. We demonstrate here that the deletion of PC3/Tis21 causes an increased proliferation of progenitor cells in the adult dentate gyrus and an arrest of their terminal differentiation. In fact, in the PC3/Tis21-null hippocampus postmitotic undifferentiated neurons accumulated, while the number of terminally differentiated neurons decreased of 40%. As a result, PC3/Tis21-null mice displayed a deficit of contextual memory. Notably, we observed that PC3/Tis21 can associate to the promoter of Id3, an inhibitor of proneural gene activity, and negatively regulates its expression, indicating that PC3/Tis21 acts upstream of Id3. Our results identify PC3/Tis21 as a gene required in the control of proliferation and terminal differentiation of newborn neurons during adult hippocampal neurogenesis and suggest its involvement in the formation of contextual memories.

Adult neurogenesis in the dentate gyrus plays a critical role in hippocampus-dependent spatial learning. It remains unknown, however, how new neurons become functionally integrated into spatial circuits and contribute to hippocampus-mediated forms of learning and memory. To investigate these issues, we used a mouse model in which the differentiation of adult-generated dentate gyrus neurons can be anticipated by conditionally expressing the pro-differentiative gene PC3 (Tis21/BTG2) in nestin-positive progenitor cells. In contrast to previous studies that affected the number of newly generated neurons, this strategy selectively changes their timing of differentiation. New, adult-generated dentate gyrus progenitors, in which the PC3 transgene was expressed, showed accelerated differentiation and significantly reduced dendritic arborization and spine density. Functionally, this genetic manipulation specifically affected different hippocampus-dependent learning and memory tasks, including contextual fear conditioning, and selectively reduced synaptic plasticity in the dentate gyrus. Morphological and functional analyses of hippocampal neurons at different stages of differentiation, following transgene activation within defined time-windows, revealed that the new, adult-generated neurons up to 3-4 weeks of age are required not only to acquire new spatial information but also to use previously consolidated memories. Thus, the correct unwinding of these key memory functions, which can be an expression of the ability of adult-generated neurons to link subsequent events in memory circuits, is critically dependent on the correct timing of the initial stages of neuron maturation and connection to existing circuits.

In the Attentional Boost Effect (ABE), words or images encoded with to-be-detected target squares are later recognized better than words or images encoded with to-be-ignored distractor squares. The present study sought to determine whether the ABE enhanced the encoding of the item-specific and relational properties of the studied words by using the multiple recall paradigm. Previous evidence indicates that manipulations fostering item-specific encoding increased the number of item gains, whereas manipulations fostering relational encoding decreased item losses. Across three experiments, participants were presented with lists of semantically related or unrelated words paired with target (red) or distractor (green) squares, under the instructions to remember all the words and press the spacebar when the square was red. Immediately after the study phase, they were involved in four consecutive recall attempts. In all cases, the classical ABE was replicated, in that participants recalled more target- than distractor-paired words. Most importantly, the analyses converged in showing that item gains were significantly greater for target- than for distractor-paired words when participants studied lists of related words (but not when they studied unrelated lists); in contrast, item losses did not differ between the two types of words, irrespective of the nature of the studied list. Taken together, these data suggest that the ABE enhanced the encoding of item-specific information but had no effect on the encoding of relational information.

Long-lasting memories of adverse experiences are essential for individuals' survival but are also involved, in the form of recurrent recollections of the traumatic experience, in the aetiology of anxiety diseases (e.g., post-traumatic stress disorder [PTSD]). Extinction-based erasure of fear memories has long been pursued as a behavioral way to treat anxiety disorders; yet, such a procedure turns out to be transient, context-dependent, and ineffective unless it is applied immediately after trauma. Recent evidence indicates that, in both rats and humans, extinction training can prevent the return of fear if administered within the reconsolidation window, when memories become temporarily labile and susceptible of being updated. Here, we show that the reconsolidation-extinction procedure fails to prevent the spontaneous recovery of a remote contextual fear memory in a mouse model of PTSD, as well as the long-lasting behavioral abnormalities induced by traumatic experience on anxiety and in both social and cognitive domains (i.e., social withdrawal and spatial learning deficits). Such a failure appears to be related to the ineffectiveness of the reconsolidation-extinction procedure in targeting the pathogenic process of fear sensitization, a nonassociative component of traumatic memory that causes animals to react aberrantly to harmless stimuli. This indicates fear sensitization as a major target for treatments aimed at mitigating anxiety and the behavioral outcomes of traumatic experiences.

Previous studies indicate that pregnancy is associated with a mild impairment in verbal recall tasks, but the relative roles of item-specific and relational encoding processes have not been fully elucidated. The present study was specifically aimed at determining whether pregnancy had a differential impact on the use of these 2 types of encoding processes. The performance of pregnant, postpartum, and control women was assessed in the category-cued recall (Experiment 1: explicit memory) and category exemplar generation (Experiment 2: implicit memory) tasks, by simultaneously varying the number of exemplars presented during the study phase (1 exemplar for small categories, 6 exemplars for large categories). Control women showed the expected crossed double dissociation: Performance in category-cued recall was better for small than for large categories (confirming that this task relied on the use of item-specific encoding processes), whereas repetition priming in category exemplar generation was higher for large than for small categories (confirming that this task relied on the use of relational encoding processes). For pregnant and postpartum women, no significant differences between small and large categories were detected in the category-cued recall task; furthermore, in the category exemplar generation task, these 2 groups exhibited greater priming for small category exemplars. Overall, our data suggest that pregnancy might involve complex changes in the use of item-specific and relational encoding processes. [ABSTRACT FROM AUTHOR]

Remembering places in which emotional events occur is essential for individual's survival. However, the mechanisms through which emotions modulate information processing in working memory, especially in the visuo-spatial domain, is little understood and controversial. The present research was aimed at investigating the effect of incidentally learned emotional stimuli on visuo-spatial working memory (VSWM) performance by using a modified version of the object-location task. Eight black rectangles appeared simultaneously on a computer screen; this was immediately followed by the sequential presentation of eight pictures (selected from IAPS) superimposed onto each rectangle. Pictures were selected considering the two main dimensions of emotions: valence and arousal. Immediately after presentation, participants had to relocate the rectangles in the original position as accurately as possible. In the first experiment arousal and valence were manipulated either as between-subject (Experiment 1A) or as within-subject factors (Experiment 1B and 1C). Results showed that negative pictures enhanced memory for object location only when they were presented with neutral ones within the same encoding trial. This enhancing effect of emotion on memory for object location was replicated also with positive pictures. In Experiment 2 the arousal level of negative pictures was manipulated between-subjects (high vs. low) while maintaining valence as a within-subject factor (negative vs. neutral). Objects associated with negative pictures were better relocated, independently of arousal. In Experiment 3 the role of emotional valence was further ascertained by manipulating valence as a within-subject factor (neutral vs. negative in Experiment 3A; neutral vs. positive in Experiment 3B) and maintaining similar levels of arousal among pictures. A significant effect of valence on memory for location was observed in both experiments. Finally, in Experiment 4, when positive and negative pictures were encoded in the same trial, no significant effect of valence on memory for object location was observed. Taken together results suggest that emotions enhance spatial memory performance when neutral and emotional stimuli compete with one another for access into the working memory system. In this competitive mechanism, an interplay between valence and arousal seems to be at work. [ABSTRACT FROM AUTHOR]

It has been recently proposed that pregnant women would perform memory tasks by focusing more on item-specific processes and less on relational processing, compared to post-partum women (Mickes, Wixted, Shapiro & Scarff, ). The present cross-sectional study tested this hypothesis by directly manipulating the type of encoding employed in the study phase. Pregnant, post-partum and control women either rated the pleasantness of word meaning (which induced item-specific elaboration) or named the semantic category to which they belonged (which induced relational elaboration). Memory for the encoded words was later tested in free recall (which emphasizes relational processing) and in recognition (which emphasizes item-specific processing). In line with Mickes et al.'s () conclusions, pregnant women in the item-specific condition performed worse than post-partum women in the relational condition in free recall, but not in recognition. However, compared to the other two groups, pregnant women also exhibited lower recognition accuracy in the item-specific condition. Overall, these results confirm that pregnant women rely on relational encoding less than post-partum women, but additionally suggest that the former group might use item-specific processes less efficiently than post-partum and control women. [ABSTRACT FROM AUTHOR]

Fear allows organisms to cope with dangerous situations and remembering these situations has an adaptive role preserving individuals from injury and death. However, recalling traumatic memories can induce re-experiencing the trauma, thus resulting in a maladaptive fear. A failure to properly regulate fear responses has been associated with anxiety disorders, like Posttraumatic Stress Disorder (PTSD). Thus, re-establishing the capability to regulate fear has an important role for its adaptive and clinical relevance. Strategies aimed at erasing fear memories have been proposed, although there are limits about their efficiency in treating anxiety disorders. To re-establish fear regulation, here we propose a new approach, based on the re-evaluation of the aversive value of traumatic experience. Mice were submitted to a contextual-fear-conditioning paradigm in which a neutral context was paired with an intense electric footshock. Three weeks after acquisition, conditioned mice were treated with a less intense footshock (pain threshold). The effectiveness of this procedure in reducing fear expression was assessed in terms of behavioral outcomes related to PTSD (e.g., hyper-reactivity to a neutral tone, anxiety levels in a plus maze task, social avoidance, and learning deficits in a spatial water maze) and of amygdala activity by evaluating c-fos expression. Furthermore, a possible role of lateral orbitofrontal cortex (IOFC) in mediating the behavioral effects induced by the re-evaluation procedure was investigated. We observed that this treatment: (i) significantly mitigates the abnormal behavioral outcomes induced by trauma; (ii) persistently attenuates fear expression without erasing contextual memory; (iii) prevents fear reinstatement; (iv) reduces amygdala activity; and (v) requires an intact IOFC to be effective. These results suggest that an effective strategy to treat pathological anxiety should address cognitive re-evaluation of the traumatic experience mediated by IOFC. [ABSTRACT FROM AUTHOR]

Abstract: The present study investigated the use of perceptual binding processes in schizophrenic (SC) patients and matched healthy controls, by examining their performance on the recall of symmetrical (vertical, horizontal and diagonal) and asymmetrical patterns varying in length between 2 and 9 items. The results showed that, although SC patients were less accurate than controls in all conditions, both groups recalled symmetrical patterns better than asymmetrical ones. The impairment of SC patients was magnified with supra-span symmetrical arrays, and they were more likely to reproduce symmetrical patterns as asymmetrical, particularly at medium and high length levels. Hierarchical regression analyses further indicated that the between-group differences in the recall of supra-span vertical and horizontal arrays, which require a greater involvement of visual pattern processes, remained significant after removing the variance associated with performance on asymmetrical patterns, which primarily reflects intrafigural spatial processes. It is proposed that schizophrenia may be associated with a specific deficit in the formation and retrieval of the global visual images of studied patterns and in the use of the on-line information about the type of symmetry being tested to guide retrieval processes. [Copyright &y& Elsevier]