Memory Retrieval

It is well established that glucocorticoid hormones, secreted by the adrenal cortex after a stressful event, influence cognitive performance. Some studies have found glucocorticoid-induced memory enhancement. However, many studies have reported impairing effects of glucocorticoids on memory function. This paper reviews recent findings from this laboratory on the acute effects of glucocorticoids in rats on specific memory phases, i.e., memory consolidation and memory retrieval. The evidence suggests that the consequences of glucocorticoid activation on cognition depend largely on the different memory phases investigated. Posttraining activation of glucocorticoid-sensitive pathways involving glucocorticoid receptors enhances memory consolidation in a pattern highly similar to that previously described for adrenal catecholamines. Also, similar to catecholamine effects on memory consolidation, glucocorticoid influences on memory consolidation depend on noradrenergic activation of the basolateral complex of the amygdala and interactions with other brain regions. By contrast, memory retrieval processes are usually impaired with high circulating levels of glucocorticoids or following infusions of glucocorticoid receptor agonists into the hippocampus. The hypothesis is proposed that these apparently dual effects of glucocorticoids on memory consolidation and memory retrieval might be related and that the basolateral complex of the amygdala is a key structure in a memory-modulatory system that regulates, in concert with other brain regions, stress and glucocorticoid effects on both memory consolidation and memory retrieval. ᭧ 2002 Elsevier Science (USA)

This research compared the effectiveness of three interview procedures for optimizing eyewitness memory performance: (a) the "cognitive interview" based on memory-retrieval mnemonics from current memory theory, (b) the presently controversial hypnosis interview, and (c) the standard (control) police interview. These methods were evaluated empirically in a controlled, yet ecologically valid, laboratory setting. Eighty-nine subjects viewed police training films of simulated violent crimes and were questioned individually in interactive interviews 48 hours later by experienced law-enforcement personnel. Both the cognitive and hypnosis procedures elicited a significantly greater number of correct items of information from the subjects than did the standard interview. This result, which held even for the most critical facts from the films, was most pronounced for crime scenarios in which the density of events was high. The number of incorrect items of information generated did not differ across the three interview conditions. The observed memory enhancement was interpreted in terms of the memory-guidance techniques common to both the cognitive and hypnosis interviews. Neither differential questioning time nor heightened subject or interviewer motivation could explain the results. the interviewers and Lisa Button, Diane Sindel, Kim O'Reilly, Robin Cohen, and Phil Gamier, who played integral roles in the conduct and analysis of the experiment.

The objective of this study was to delineate a common functional network that underlies autobiographical, episodic, and semantic memory retrieval. We conducted an event-related fMRI study in which we utilized the same pictorial stimuli, but manipulated retrieval demands to extract autobiographical, episodic, or semantic memories. To assess this common network, we first examined the functional connectivity of regions identified by a previous analysis of task-related activity that were active across all three tasks. Three of these regions (left hippocampus, left lingual gyrus, and right caudate nucleus) appeared to share a common pattern of connectivity. This was confirmed in a subsequent functional connectivity analysis using these three regions as seeds. The results of this analysis showed that there was a pattern of functional connectivity that characterized all three seeds and that was common across the three retrieval conditions. Activity in inferior frontal and middle temporal cortex bilaterally, left temporoparietal junction, and anterior and posterior cingulate gyri was positively correlated with the seeds, whereas activity in posterior occipitotemporo-parietal regions was negatively correlated. These findings support the idea that a common neural network underlies the retrieval of declarative memories regardless of memory content. This proposed network consists of increased activity in regions that represent internal processes of memory retrieval and decreased activity in regions that mediate attention to external stimuli.

This research compared the effectiveness of three interview procedures for optimizing eyewitness memory performance: (a) the "cognitive interview" based on memory-retrieval mnemonics from current memory theory, (b) the presently controversial hypnosis interview, and (c) the standard (control) police interview. These methods were evaluated empirically in a controlled, yet ecologically valid, laboratory setting. Eighty-nine subjects viewed police training films of simulated violent crimes and were questioned individually in interactive interviews 48 hours later by experienced law-enforcement personnel. Both the cognitive and hypnosis procedures elicited a significantly greater number of correct items of information from the subjects than did the standard interview. This result, which held even for the most critical facts from the films, was most pronounced for crime scenarios in which the density of events was high. The number of incorrect items of information generated did not differ across the three interview conditions. The observed memory enhancement was interpreted in terms of the memory-guidance techniques common to both the cognitive and hypnosis interviews. Neither differential questioning time nor heightened subject or interviewer motivation could explain the results. the interviewers and Lisa Button, Diane Sindel, Kim O'Reilly, Robin Cohen, and Phil Gamier, who played integral roles in the conduct and analysis of the experiment.

The Cognitive Interview was tested in the field to enhance the recollection of actual victims and witnesses of crime. The technique is based on laboratory-tested principles of memory retrieval, knowledge representation, and communication. Seven experienced detectives from the Metro-Dade Police Department were trained to use the technique and were compared with 9 untrained detectives. Before and after training, all detectives tape-recorded interviews with victims and witnesses of crime. The trained detectives elicited 47% more information after than before training, and 63% more information than did the untrained detectives. Overall collaboration rates (94%) were extremely high and were equivalent for pre-and posttrained interviews. Because the Cognitive Interview reliably enhances memory and is easily learned and administered, it should be useful for a variety of investigative interviews.

Although rumination is an important mediator of depressive symptoms, there is insufficient proof that an intervention that specifically targets rumination ameliorates the clinical condition of, depressed patients. This study investigates whether a time-limited cognitive behavioral intervention (Competitive Memory Training, or COMET for depressive rumination) is an effective treatment for depression and rumination. This intervention was tested in older adult depressed outpatients. A total of 93 patients (aged !65 years with major depression and suffering from rumination) were treated in small groups according to the COMET protocol in addition to their regular treatment. Patients were randomized to two treatment conditions: 7 weeks of COMET þ treatment-as-usual (TAU) versus TAU only. COMET þ TAU showed a significant improvement in depression and rumination compared with TAU alone. This study shows that the transdiagnostic COMET protocol for depressive rumination might also be successful in treating depression and rumination in older adults.

Two studies of autobiographical memory explored the hypothesis that memories become more accessible when the linguistic environment at retrieval matches the linguistic environment at encoding. In Experiment 1, Russian-English bilinguals were asked to recall specific life experiences in response to word prompts. The results supported the hypothesis of language-dependent recall: Participants retrieved more experiences from the Russian-speaking period of their lives when interviewed in Russian and more experiences from the English-speaking period of their lives when interviewed in English. In Experiment 2, the language of the interview was varied independently from the language of the word prompts. Both variables were found to influence autobiographical recall. These findings show that language at the time of retrieval, like other forms of context, plays a significant role in determining what will be remembered.

The present fMRI study investigates, first, whether learning new arithmetic operations is reflected by changing cerebral activation patterns, and second, whether different learning methods lead to differential modifications of brain activation. In a controlled design, subjects were trained over a week on two new complex arithmetic operations, one operation trained by the application of back-up strategies, i.e., a sequence of arithmetic operations, the other by drill, i.e., by learning the association between the operands and the result. In the following fMRI session, new untrained items, items trained by strategy and items trained by drill, were assessed using an eventrelated design. Untrained items as compared to trained showed large bilateral parietal activations, with the focus of activation along the right intraparietal sulcus. Further foci of activation were found in both inferior frontal gyri. The reverse contrast, trained vs. untrained, showed a more focused activation pattern with activation in both angular gyri. As suggested by the specific activation patterns, newly acquired expertise was implemented in previously existing networks of arithmetic processing and memory. Comparisons between drill and strategy conditions suggest that successful retrieval was associated with different brain activation patterns reflecting the underlying learning methods. While the drill condition more strongly activated medial parietal regions extending to the left angular gyrus, the strategy condition was associated to the activation of the precuneus which may be accounted for by visual imagery in memory retrieval. D

Using survey responses (n = 401) of a sample of households in one market area in Austria, we test hypotheses grounded in accessibility theory: a concept or object may be 'available' from memory but may be 'accessible' only under certain conditions. Accessibility estimates strength of the cue-to-object link: a strong link facilitates retrieval of the object upon presentation of the cue. Hypotheses: (HI) top-of-mind, associate-to-store memory-retrievals are associated with most frequent choice (e.g., a consumer's primary store); (H2) each competing store (or brand) in a product-market has a unique configuration of top-of-mind, associate-to-store retrievals linked with its selection as primary store choice; (H3) each store, among two or more stores having the same name and operated by the same management and located in the same geographic market, has a unique configuration of top-of-mind, associate-to-store associations with its selection as primary store choice; and (H4) situational factors (e.g., problem contexts) are powerful framing influences that result in changing both the associations among top-of-mind, associate-to-store retrievals and the consumer's primary store choice. The findings provide support for the first, second, and fourth hypotheses, but only partial support for the third. © 1997 Elsevier Science B.V.

We are virtually learning all the time from our sensory stimuli. Sometimes we do it consciously and sometimes unconsciously. Basically, we absorb certain information from outside, convert them to suit our physiology and process them to guide our behaviour and thoughts and that is the essence of learning. Cognitive science largely attributes this entire process to the brain, which is the main processing center for information, in a human body. Cognitive learning is associated with ''thinking with the brain'', to learn, however, renowned psychologists have confirmed that the human mind is not that developed to think. Thinking can be 'slow, effortful and uncertain', hence we have to rely on our past habits and memories to guide our actions, so that we do not have to think deliberately and deeply. This study aims to understand the role of memory formation in cognitive learning; we will also discuss the role of hippocampus in memory building and storing, based on established scientific theories, case studies and experiments. Retrieval of memories is also required to further cognitive learning, for if we cannot remember what we have learned, the stored the process previous information will be of no use; learning will not take place. In the paper, we will discuss about the effective ways in which stored memory can be retrieved easily, and help in learning.

The cognitive literature now shows how critically math performance depends on working memory, for any form of arithmetic and math that involves processes beyond simple memory retrieval. The psychometric literature is also very clear on the global consequences of mathematics anxiety. People who are highly math anxious avoid math: They avoid elective coursework in math, both in high school and college, they avoid college majors that emphasize math, and they avoid career paths that involve math. We go beyond these psychometric relationships to examine the cognitive consequences of math anxiety. We show how performance on a standardized math achievement test varies as a function of math anxiety, and that math anxiety compromises the functioning of working memory. High math anxiety works much like a dual task setting: Preoccupation with one’s math fears and anxieties functions like a resource-demanding secondary task. We comment on developmental and educational factors related to math and working memory, and on factors that may contribute to the development of math anxiety.

Theories of autobiographical memory emphasise effortful, generative search processes in memory retrieval. However recent research suggests that memories are often retrieved
directly, without effortful search. We investigated whether direct and generative retrieval differed in the characteristics of memories recalled, or only in terms of retrieval latency.
Participants recalled autobiographical memories in response to cue words. For each memory, they reported whether it was retrieved directly or generatively, rated its visuo-spatial
perspective, and judged its accompanying recollective experience. Our results indicated that direct retrieval was commonly reported and was faster than generative retrieval, replicating recent findings. The characteristics of directly retrieved memories differed from generatively retrieved memories: directly retrieved memories had higher field perspective ratings and lower observer perspective ratings. However, retrieval mode did not influence recollective experience. We discuss our findings in terms of cue generation and content construction, and the implication for reconstructive models of autobiographical memory.

Cognitive stimulation via the exposure to ideas of other people is an effective tool in stimulating creativity in group-based creativity techniques. In this fMRI study, we investigate whether creative cognition can be enhanced through idea sharing and how performance improvements are reflected in brain activity. Thirtyone participants had to generate alternative uses of everyday objects during fMRI recording. Additionally, participants performed this task after a time period in which they had to reflect on their ideas or in which they were confronted with stimulus-related ideas of others. Cognitive stimulation was effective in improving originality, and this performance improvement was associated with activation increases in a neural network including right-hemispheric temporo-parietal, medial frontal, and posterior cingulate cortices, bilaterally. Given the involvement of these brain areas in semantic integration, memory retrieval, and attentional processes, cognitive stimulation could have resulted in a modulation of bottom-up attention enabling participants to produce more original ideas.

AbstractöMost functional imaging studies of memory retrieval investigate memory for standardized laboratory stimuli. However, naturally acquired autobiographical memories di¡er from memories of standardized stimuli in important ways. Neuroimaging studies of natural memories may reveal distinctive patterns of brain activation and may have particular value in assessing clinical disorders of memory. This study used functional magnetic resonance imaging to investigate brain activation during successful retrieval of autobiographical memories elicited by name-cued recall of family members and friends. The caudal part of the left posterior cingulate cortex was the most strongly activated region and was signi¢cantly activated in all eight subjects studied. Most subjects also showed signi¢cant activation of the left anterior orbitomedial, anterior middle frontal, precuneus, cuneus, and posterior inferior parietal cortices, and the right posterior cingulate and motor cortices.

The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval.

Surprisingly little is known about the neural correlates of remembering real life events in the context of normal aging. We therefore asked young and older adults to retrieve real life autobiographical event memories accrued over decades, while their brains were scanned using functional MRI. There were many commonalities between the groups in the wider network of brain areas active during retrieval. Nevertheless, one key difference emerged; while left hippocampal activation was apparent in the young, bilateral hippocampal activation was evident in older adults and direct comparison between the groups con®rmed signi®cantly greater right hippocampal activation in older adults. Notably, this difference was speci®c to autobiographical event memory retrieval, as the groups were comparable in the areas active during semantic memory retrieval. The present ®ndings show that even when stimuli, tasks and performance appear indistinguishable between young and older adults, neural changes occur in aging with speci®city in both the memory type and the brain regions affected. In particular, the results reveal that agerelated effects are detectable in the hippocampus. This highlights the need to consider how the dynamic course of normal aging interacts with pathological processes that might also affect the hippocampus. Understanding this relationship may aid prognosis, as well as providing insights into plasticity in the anatomy of memory.

Over the last decades considerable evidence has accumulated indicating that glucocorticoids -stress hormones released from the adrenal cortex -are crucially involved in the regulation of memory. Specifically, glucocorticoids have been shown to enhance memory consolidation of emotionally arousing experiences, but impair memory retrieval and working memory during emotionally arousing test situations. Furthermore, growing evidence indicates that these different glucocorticoid effects all depend on emotional arousal-induced activation of noradrenergic transmission within the basolateral complex of the amygdala (BLA) and on interactions of the BLA with other brain regions, such as the hippocampus and neocortical regions. Here we review findings from both animal and human experiments and present an integrated perspective of how these opposite glucocorticoid effects might act together to serve adaptive processing of emotionally significant information. Furthermore, as intense emotional memories also play a crucial role in the pathogenesis and symptomatology of anxiety disorders, such as posttraumatic stress disorder (PTSD) or phobias, we discuss to what extent the basic findings on glucocorticoid effects on emotional memory might have implications for the understanding and treatment of these clinical conditions. In this context, we review data suggesting that the administration of glucocorticoids might ameliorate chronic anxiety by reducing retrieval of aversive memories and enhancing fear extinction.

Though emotion conveys memory benefits, it does not enhance memory equally for all aspects of an experience nor for all types of emotional events. In this review, I outline the behavioral evidence for arousal's focal enhancements of memory and describe the neural processes that may support those focal enhancements. I also present behavioral evidence to suggest that these focal enhancements occur more often for negative experiences than for positive ones. This effect of valence appears to arise because of valence-dependent effects on the neural processes recruited during episodic encoding and retrieval, with negative affect associated with increased engagement of sensory processes and positive affect leading to enhanced recruitment of conceptual processes.

The temporal relations among word-list items exert a powerful influence on episodic memory retrieval. Two experiments were conducted with younger and older adults in which the age-related recall deficit was examined by using a decomposition method to the serial position curve, partitioning performance into (a) the probability of first recall, illustrating the recency effect, and (b) the conditional response probability, illustrating the lag recency effect (M. W. Howard & M. J. . Although the older adults initiated recall in the same manner in both immediate and delayed free recall, temporal proximity of study items (contiguity) exerted a much weaker influence on recall transitions in older adults. This finding suggests that an associative deficit may be an important contributor to older adults' well-known impairment in free recall.

The Cognitive Interview was tested in the field to enhance the recollection of actual victims and witnesses of crime. The technique is based on laboratory-tested principles of memory retrieval, knowledge representation, and communication. Seven experienced detectives from the Metro-Dade Police Department were trained to use the technique and were compared with 9 untrained detectives. Before and after training, all detectives tape-recorded interviews with victims and witnesses of crime. The trained detectives elicited 47% more information after than before training, and 63% more information than did the untrained detectives. Overall collaboration rates (94%) were extremely high and were equivalent for pre-and posttrained interviews. Because the Cognitive Interview reliably enhances memory and is easily learned and administered, it should be useful for a variety of investigative interviews.

Background. Cognitive deficits are common in major depressive disorder, but their nature is unclear. The effort hypothesis states that performance on effortful tasks is disproportionately impaired compared with the performance on automatic tasks. The cognitive speed hypothesis states that depression is characterized by cognitive slowness, which is a source of cognitive dysfunctioning. The present study investigated both theories in unmedicated adult depressive patients. It was also investigated whether the cognitive deficits can be attributed to more general physical illness-related factors or specifically to depressive disorder.

Measures of the speed and accuracy of processing sentences with nonadjacent dependencies derived from the response-signal speed-accuracy tradeoff procedure were used to examine the nature of the memory system that underlies sentence comprehension. Three experiments with different sentence structures demonstrated that the accuracy of processing a dependency decreased as more material was interpolated between nonadjacent constituents. However, processing speed was unaffected by the amount of interpolated material, indicating that memory representations for previously processed constituents can be accessed directly. These results suggest that a content-addressable memory system mediates sentence comprehension, in which syntactic and semantic information provide direct access to memory representations without the need to search through extraneous representations. Notably, content-addressability appears to underlie the interpretation of sentence structures that also require the recovery of order information, a type of operation that has been shown to necessitate a slow search process in list-learning experiments .

This paper presents the cue-based retrieval theory of parsing and reanalysis and illustrates how this account can accommodate a number of key results about parsing and reanalysis, including effects due to structure, distance, and type of structural change. Three offline experiments and one online experiment permit establishing the locus of these effects as due to properties of the initial parsing processes or to the repair mechanism. Specifically, the data reported here suggest that a structural factor specific to the operation of the parser, retrieval interference, affects attachment uniformly across ambiguous and unambiguous sentences and serves to create a limit on successful repair. In addition, these experiments suggest that distance of the head of an ambiguous phrase from its disambiguator affects repair processes-and not attachment processes-independently of the interference effect. These results are interpreted with respect to alternative models of reanalysis, which are contrasted with the cue-based retrieval account, which requires no distinct repair mechanism to account for the current results. A further contribution of this article is to suggest a statistical correction for individual variance in reading rates. Statistical analyses on individual subject data confirmed previous speculations regarding a possible increase in reading rates as subjects move through a sentence. While this individual variation limits fair comparisons of reading times in sentence regions that appear in non-identical serial positions, we demonstrate that such comparisons become meaningful when the appropriate regression analyses have been performed.

Deferred imitation was used to trace changes in memory retrieval by 18-30-month-olds. In all experiments, an adult demonstrated 2 sets of actions using 2 different sets of stimuli. In Experiments 1A and IB, independent groups of infants were tested immediately or after a 24-hr delay. Each infant was tested with 1 set of stimuli from the original demonstration and 1 set of stimuli that was different. Recall of the target actions when tested with different stimuli increased as a function of age, particularly after a delay. In Experiment 2, infants were provided with a unique verbal label for the stimuli during the demonstration and the test. The verbal label facilitated performance by 24-month-olds tested with different stimuli but had no effect on performance by 18-month-olds. One hallmark of memory development appears to be an age-related increase in the range of effective retrieval cues for a particular memory.

This research extends the dual coding theory of memory retrieval beyond its traditional focus on verbal and pictorial information to olfactory information. We manipulate the presence or absence of olfactory and pictorial stimuli at the time of encoding (study 1) or retrieval (study 2) and measure the impact on verbal recall. After a time delay, scent enhances recall of verbal information, and scent-based retrieval cues potentiate the facilitative effect of pictures on recall. These results cannot be attributed merely to increased elaboration at the time of exposure.

Memory retrieval is a fundamental component or stage of memory processing. In fact, retrieval is the only possible measure of memory. The ability to recall past events is a major determinant of survival strategies in all species and is of paramount importance in determining our uniqueness as individuals. Most biological studies of memory using brain lesion and/or gene manipulation techniques cannot distinguish between effects on the molecular mechanisms of the encoding or consolidation of memories and those responsible for their retrieval from storage. Here we examine recent findings indicating the major molecular steps involved in memory retrieval in selected brain regions of the mammalian brain. Together the findings strongly suggest that memory formation and retrieval may share some molecular mechanisms in the hippocampus and that retrieval initiates extinction requiring activation of several signaling cascades and protein synthesis.

Recall of words from categorised lists was examined in 77 patients and 12 normal control subjects. In Experiment I, both left temporal-lobe excisions that included the hippocampus (LTH) and left frontal-lobe removals (LF) impaired free recall, but the LF group performed normally when encoding and retrieval strategies were supplied. In Experiment 2, experimentally induced interference during cued recall abnormally hampered performance for the LF, but not for the LTH group.

Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evidence from both animal and human research indicates that emotionally significant experiences activate hormonal and brain systems that regulate the consolidation of newly acquired memories. These effects are integrated through noradrenergic activation of the basolateral amygdala which regulates memory consolidation via interactions with many other brain regions involved in consolidating memories of recent experiences. Modulatory systems not only influence neurobiological processes underlying the consolidation of new information, but also affect other mnemonic processes, including memory extinction, memory recall and working memory. In contrast to their enhancing effects on consolidation, adrenal stress hormones impair memory retrieval and working memory. Such effects, as with memory consolidation, require noradrenergic activation of the basolateral amygdala and interactions with other brain regions.

The neural correlates of conscious awareness during successful memory retrieval were examined. In a recognition test, subjects indicated whether they consciously recalled the event in which a word was earlier presented (Remembering), or whether they recognized it on the basis that it was familiar in the absence of recollection (Knowing). An early EEG synchronization in the theta band predicted knowing, and a later remembering. Moreover, early and late event-related potentials were also found to predict knowing and remembering, respectively. The results indicate that the temporal dynamics of theta synchronization are related to the particular conscious experiences associated with memory retrieval.

Long-term memories are influenced by the emotion experienced during learning as well as by the emotion experienced during memory retrieval. The present article reviews the literature addressing the effects of emotion on retrieval, focusing on the cognitive and neurological mechanisms that have been revealed. The reviewed research suggests that the amygdala, in combination with the hippocampus and prefrontal cortex, plays an important role in the retrieval of memories for emotional events. The neural regions necessary for online emotional processing also influence emotional memory retrieval, perhaps through the reexperience of emotion during the retrieval process.

AMPA 2-amino-3-hydroxy-5-methyl-4-isoxazole proprionate EEG electro-encephalogram LIA large irregular activity in hippocampal EEG LTD long-term depression LTP long-term potentiation NMDA N-methyl-D-aspartate REMS rapid eye movement (paradoxical) sleep SWS slow-wave sleep

Memory suppression refers to the ability to exclude distracting memories from conscious awareness, and this ability can be assessed with the think/no-think paradigm. Recent research with older adults has provided evidence suggesting both intact and deficient memory suppression. The present studies seek to understand the conditions contributing to older adults’ ability to suppress memories voluntarily. We report 2 experiments
indicating that the specificity of the think/no-think task instructions contributes to older adults’ suppression
success: When older adults receive open-ended instructions that require them to develop a retrieval suppression
strategy on their own, they show diminished memory suppression compared with younger adults. Conversely, when older adults receive focused instructions directing them to a strategy thought to better isolate inhibitory control, they show suppression-induced forgetting similar to that exhibited by younger adults. Younger adults demonstrate memory suppression regardless of the specificity of the instructions given, suggesting that the ability to select a successful suppression strategy spontaneously may be compromised in
older adults. If so, this deficit may be associated with diminished control over unwanted memories in naturalistic settings if impeded strategy development reduces the successful deployment of inhibitory control.

The paper explores the effects of adding audio description to an educational film on children's learning behaviour, manifested by a visual recognition task. We hypothesize that the multimodal educational setting, consisting of both verbal (film dialogue and audio description) and non-verbal (motion pictures) representations of knowledge, fosters knowledge acquisition as it provides information via multiple channels, which in turn strengthens

BACKGROUND: Gender is known to modulate the clinical course and severity of bipolar disorder (BD). Although cognitive abnormalities are an established feature of BD, there is limited information regarding whether gender also influences the pattern and severity of cognitive impairment.METHOD: We evaluated the performance of 86 remitted patients with BD, type 1, (BD-I) (36 male and 50 female) and 46 healthy participants (21 male and 25 female) on tasks of general intellectual ability, memory encoding, recognition and retrieval, response inhibition and executive function (abstraction and perseveration). The impact of illness severity in patients was assessed using the global assessment of functioning (GAF).RESULTS: We found a gender effect and an interaction between diagnosis and gender on immediate memory, implicating encoding and retrieval processes, both showing male BD-I patients being disadvantaged compared with female patients and healthy controls. Immediate memory correlated with GAF scores and this association was statistically significant for male BD-I patients.CONCLUSIONS: Our findings suggest that gender differences in BD-I are associated with memory function, particularly processes relating to encoding and retrieval, and may contribute to poor functional outcome particularly in men.

Remembering a past experience can, surprisingly, cause forgetting. Forgetting arises when other competing traces interfere with retrieval and inhibitory control mechanisms are engaged to suppress the distraction they cause. This form of forgetting is considered to be adaptive because it reduces future interference. The effect of this proposed inhibition process on competing memories has, however, never been observed, as behavioral methods are ‘blind’ to retrieval dynamics and neuroimaging methods have not isolated retrieval of individual memories. We developed a canonical template tracking method to quantify the activation state of individual target memories and competitors during retrieval. This method revealed that repeatedly retrieving target memories suppressed cortical patterns unique to competitors. Pattern suppression was related to engagement of prefrontal regions that have been implicated in resolving retrieval competition and, critically, predicted later forgetting. Thus, our findings demonstrate a cortical pattern suppression mechanism through which remembering adaptively shapes which aspects of our past remain accessible.

The aim of this article was to provide experimental evidence that classical dissociation between levels of consciousness associated with memory retrieval (i.e., implicit or explicit) can be explained in terms of task dependency and distinctiveness of traces. In our study phase, we manipulated the level of isolation (partial vs. global) of the memory trace by means of an isolation paradigm (isolated words among non-isolated words). We then tested these two types of isolation in a series of tasks of increasing complexity: a lexical decision task, a recognition task, and a free recall task. The main result of this study was that distinctiveness effects were observed as a function of the type of isolation (level of isolation) and the nature of the task. We concluded that trace distinctiveness improves subsequent access to the trace, while the level of trace distinctiveness also appears to determine the possibility of conscious or explicit retrieval.

Imagery research typically deals with the commonalities and differences between imagery and perception. As such, it is usually confined to one specific modality. Yet, it is likely that some of the underlying processes are shared between different sensory modalities while others are modality-specific. In this fMRI study, we used a balanced design that allowed for a direct comparison between imagery and perception in visual and auditory modalities, and also for a link between subjective imagery experience and brain activation. Results indicated a selective role for the "default mode network" as a modality-independent "core" imagery network. In addition, results identified areas in the visual and auditory association cortices that contributed to mental imagery in a modality-specific fashion. Interestingly during mental imagery, primary visual and auditory cortices showed modality-specific suppression of activity. This is the first fMRI study to characterize both modality-specific and modality-independent components of the human imagery system.

The cholinergic hypothesis of Alzheimer disease (AD) has provided the rationale for the current pharmacotherapy of this disease, in an attempt to downgrade the cognitive decline caused by cholinergic deficits. Nevertheless, the search for potent and long-acting acetylcholinesterase (AChE) inhibitors that exert minimal side effects to AD patients is still an ongoing effort. Amazonian communities use traditional remedies prepared with Ptychopetalum olacoides (PO, Olacaceae) roots for treating various central nervous system conditions, including those associated with aging. The fact that PO ethanol extract (POEE) has been found to facilitate memory retrieval in the step down procedure in young and aged mice prompt us to evaluate its effects on AChE activity in memory relevant brain areas. POEE significantly inhibited AChE activity in vitro in a dose-and time-dependent manner in rat frontal cortex, hippocampus and striatum; a significant inhibition was also found in these same brain areas of aged (14 months) mice after acute administration of POEE (100 mg/kg ip). We propose that such AChE inhibitory activity is a neurochemical correlate of a number of therapeutic properties traditionally claimed for P. olacoides, particularly those associated with cognition. D

Recent studies suggest that the content of confabulation is mainly positive and self-enhancing. In this group study, we aimed to investigate whether this positive bias is specific to self-referent information. Confabulating amnesic patients, amnesic non-confabulating patients and healthy controls were asked to reproduce a series of short stories. We manipulated the emotional valence of the material by including positive, negative and neutral story plots. We also manipulated the self-reference of the material by including self-referent versus other-referent encoding instructions.

In this study we investigated the neurocognitive processes underlying the control of memory retrieval. In a Think/No-Think paradigm, adopted for the use in an event-related potential (ERP) experiment, participants learned word pairs and were subsequently presented with cue words and asked to either suppress or to recall the target word. During final cued recall tests for all initially learned targets, memory for the to-be-suppressed or to be-recalled items were tested. Memory for to be-recalled items was enhanced but no forgetting of to-be-suppressed items was obtained. The ERPs in the test phase were separated on the basis of prior learning success and failure, allowing separate analyses of strategic memory control, i.e. attempts to retrieve or to avoid retrieval and the outcome of these processes, i.e. successful retrieval and retrieval avoidance. An early P2 component and a parietal positivity were related to retrieval attempts and a centro-parietal N2 component was associated with attempts to avoid memory retrieval. The parietal positivity was attenuated for No-Think trials on learned items, for which item-specific memories exist. However, under the present testing conditions and in contrast to prior studies the parietal positivity was also sensitive to mere retrieval attempts. To examine whether similar neural systems are involved in the inhibitory control of unwanted memories and prepotent motor responses, a motor stopping experiment using a stop signal task was conducted with the same participants. Successful stopping was associated with an enhanced stop signal N2 that showed a similar centro-parietal scalp distribution as the aforementioned N2 to No-Think trials. As both components were significantly correlated, we assumed that some of the systems recruited to override prepotent motor responses are also involved to suppress memory retrieval. ava i l a b l e a t w w w. s c i e n c e d i r e c t . c o m w w w. e l s ev i e r. c o m / l o c a t e / b r a i n r e s

Calculating prodigies are individuals who are exceptional at quickly and accurately solving complex mental calculations. With positron emission tomography (PET), we investigated the neural bases of the cognitive abilities of an expert calculator and a group of non-experts, contrasting complex mental calculation to memory retrieval of arithmetic facts. We demonstrated that calculation expertise was not due to increased activity of processes that exist in non-experts; rather, the expert and the non-experts used different brain areas for calculation. We found that the expert could switch between short-term effort-requiring storage strategies and highly efficient episodic memory encoding and retrieval, a process that was sustained by right prefrontal and medial temporal areas.

Mood-congruent cognitive biases constitute critical factors for the vulnerability to depression and its maintenance. One important aspect is impaired memory for positive information during depression and after recovery. To elucidate its state (during depression only) and trait (during depression and recovery) related neural bases, we investigated medication free depressed, recovered, and healthy individuals with functional MRI while they memorized and recognized happy and neutral face stimuli. The imaging results revealed group differences in mood-incongruent successful memory encoding and retrieval activity already in the absence of significant memory performance differences. State effects were observed in the amygdala and posterior cingulate cortex. Whereas the amygdala was generally involved in memory formation, its activity predicted subsequent forgetting of neutral faces in depressed patients. Furthermore, the amygdala and posterior cingulate cortex were involved in memory retrieval of happy faces in depressed patients only. Trait effects were observed in the fusiform gyrus and prefrontal cortex. The fusiform gyrus was involved in memory formation and retrieval of happy faces in both patient groups, whereas it was involved in memory formation and retrieval of neutral faces in healthy individuals. Similar trait effects were observed during memory retrieval in the orbitofrontal cortex and left inferior frontal gyrus. Thus, while memory processing of positive information in the amygdala and posterior cingulate cortex is biased during depression only, memory processing in the fusiform gyrus and prefrontal cortex is biased also after recovery. These distinct neural mechanisms may respectively constitute symptom maintenance and cognitive vulnerability factors for depression.

Recent studies suggest that the content of confabulation is mainly positive and self-enhancing. In this group study, we aimed to investigate whether this positive bias is specific to self-referent information. Confabulating amnesic patients, amnesic non-confabulating patients and healthy controls were asked to reproduce a series of short stories. We manipulated the emotional valence of the material by including positive, negative and neutral story plots. We also manipulated the self-reference of the material by including self-referent versus other-referent encoding instructions.Confabulating patients were as impaired as a group of amnesic patients in the amount of information they recalled, both groups being worse than healthy controls. Importantly, confabulating patients showed a selective bias in the negative self-referent condition, in that they recalled such information in a manner which portrayed a more positive image of themselves. This positive bias was not present in stories that were not encoded in a self-referent manner and it was not significantly correlated to patients’ self-reported mood. We propose that both confabulation and its motivated content result from a deficit in the control and regulation of memory retrieval, which allows motivational factors to acquire a greater role than usual in determining which memories are selected for retrieval. To this extent, the self-enhancing content of confabulation could be explained as a neurogenic exaggeration of normal self-serving memory distortion.