Extinction and recovery of an avoidance memory impaired by scopolamine.

PubMed

Navarro, N M; Krawczyk, M C; Boccia, M M; Blake, M G

2017-03-15

Pre-training administration of scopolamine (SCP) resembles situations of cholinergic dysfunction, leading to memory impairment of mice trained in an inhibitory avoidance task. We suggest here that SCP does not impair memory formation, but acquisition is affected in a way that reduces the strength of the stored memory, thus making this memory less able to control behavior when tested. Hence, a memory trace is stored, but is poorly expressed during the test. Although weakly expressed, this memory shows extinction during successive tests, and can be strengthened by using a reminder. Our results indicate that memories stored under cholinergic dysfunction conditions seem absent or lost, but are in fact present and experience common memory processes, such as extinction, and could be even recovered by using appropriate protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

Inhibition of transcription and translation in the striatum after memory reactivation: Lack of evidence of reconsolidation.

PubMed

Prado-Alcalá, Roberto A; Medina, Andrea Cristina; Bello-Medina, Paola C; Quirarte, Gina L

2017-07-01

It has been found that interference with neural activity after a consolidated memory is retrieved produces an amnestic state; this has been taken has indicative of destabilization of the memory trace that would have been produced by a process of reconsolidation (allowing for maintenance of the original trace). However, a growing body of evidence shows that this is not a reliable effect, and that it is dependent upon some experimental conditions, such as the age of the memory, memory reactivation procedures, the predictability of the reactivation stimulus, and strength of training. In some instances, where post-retrieval treatments induce a retention deficit (which would be suggestive of interference with reconsolidation), memory is rescued by simple passing of time or by repeated retention tests. We now report that post-training and post-retrieval inhibition of transcription and translation in dorsal striatum, a structure where both of these manipulations have not been studied, produce interference with consolidation and a transitory retention deficit, respectively. These results do not give support to the reconsolidation hypothesis and lead to the conclusion that the post-activation deficiencies are due to interference with retrieval of information. Copyright © 2016 Elsevier Inc. All rights reserved.

Differential effects of acute cortisol administration on deep and shallow episodic memory traces: a study on healthy males.

PubMed

Cioncoloni, David; Galli, Giulia; Mazzocchio, Riccardo; Feurra, Matteo; Giovannelli, Fabio; Santarnecchi, Emiliano; Bonifazi, Marco; Rossi, Alessandro; Rossi, Simone

2014-10-01

We aimed at investigating rapid effects of plasma cortisol elevations on the episodic memory phase of encoding or retrieval, and on the strength of the memory trace. Participants were asked either to select a word containing the letter "e" (shallow encoding task) or to judge if a word referred to a living entity (deep encoding task). We intravenously administered a bolus of 20mg of cortisol either 5 min before encoding or 5 min before retrieval, in a between-subjects design. The study included only male participants tested in the late afternoon, and neutral words as stimuli. When cortisol administration occurred prior to retrieval, a main effect of group emerged. Recognition accuracy was higher for individuals who received cortisol compared to placebo. The higher discrimination accuracy for the cortisol group was significant for words encoded during deep but not shallow task. Cortisol administration before encoding did not affect subsequent retrieval performance (either for deep or shallow stimuli) despite a facilitatory trend. Because genomic mechanisms take some time to develop, such a mechanism cannot apply to our findings where the memory task was performed shortly after the enhancement of glucocorticoid levels. Therefore, glucocorticoids, through non-genomic fast effects, determine an enhancement in episodic memory if administered immediately prior to retrieval. This effect is more evident if the memory trace is laid down through deep encoding operations involving the recruitment of specific neural networks. Copyright © 2014 Elsevier Inc. All rights reserved.

Regulators of Long-Term Memory Revealed by Mushroom Body-Specific Gene Expression Profiling in Drosophila melanogaster.

PubMed

Widmer, Yves F; Bilican, Adem; Bruggmann, Rémy; Sprecher, Simon G

2018-06-20

Memory formation is achieved by genetically tightly controlled molecular pathways that result in a change of synaptic strength and synapse organization. While for short-term memory traces rapidly acting biochemical pathways are in place, the formation of long-lasting memories requires changes in the transcriptional program of a cell. Although many genes involved in learning and memory formation have been identified, little is known about the genetic mechanisms required for changing the transcriptional program during different phases of long-term memory formation. With Drosophila melanogaster as a model system we profiled transcriptomic changes in the mushroom body, a memory center in the fly brain, at distinct time intervals during appetitive olfactory long-term memory formation using the targeted DamID technique. We describe the gene expression profiles during these phases and tested 33 selected candidate genes for deficits in long-term memory formation using RNAi knockdown. We identified 10 genes that enhance or decrease memory when knocked-down in the mushroom body. For vajk-1 and hacd1 , the two strongest hits, we gained further support for their crucial role in appetitive learning and forgetting. These findings show that profiling gene expression changes in specific cell-types harboring memory traces provides a powerful entry point to identify new genes involved in learning and memory. The presented transcriptomic data may further be used as resource to study genes acting at different memory phases. Copyright © 2018, Genetics.

Dietary effects on object recognition: The impact of high-fat high-sugar diets on recollection and familiarity-based memory.

PubMed

Tran, Dominic M D; Westbrook, R Frederick

2018-05-31

Exposure to a high-fat high-sugar (HFHS) diet rapidly impairs novel-place- but not novel-object-recognition memory in rats (Tran & Westbrook, 2015, 2017). Three experiments sought to investigate the generality of diet-induced cognitive deficits by examining whether there are conditions under which object-recognition memory is impaired. Experiments 1 and 3 tested the strength of short- and long-term object-memory trace, respectively, by varying the interval of time between object familiarization and subsequent novel object test. Experiment 2 tested the effect of increasing working memory load on object-recognition memory by interleaving additional object exposures between familiarization and test in an n-back style task. Experiments 1-3 failed to detect any differences in object recognition between HFHS and control rats. Experiment 4 controlled for object novelty by separately familiarizing both objects presented at test, which included one remote-familiar and one recent-familiar object. Under these conditions, when test objects differed in their relative recency, HFHS rats showed a weaker memory trace for the remote object compared to chow rats. This result suggests that the diet leaves intact recollection judgments, but impairs familiarity judgments. We speculate that the HFHS diet adversely affects "where" memories as well as the quality of "what" memories, and discuss these effects in relation to recollection and familiarity memory models, hippocampal-dependent functions, and episodic food memories. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Transient acidosis while retrieving a fear-related memory enhances its lability

PubMed Central

Du, Jianyang; Price, Margaret P; Taugher, Rebecca J; Grigsby, Daniel; Ash, Jamison J; Stark, Austin C; Hossain Saad, Md Zubayer; Singh, Kritika; Mandal, Juthika; Wemmie, John A; Welsh, Michael J

2017-01-01

Attenuating the strength of fearful memories could benefit people disabled by memories of past trauma. Pavlovian conditioning experiments indicate that a retrieval cue can return a conditioned aversive memory to a labile state. However, means to enhance retrieval and render a memory more labile are unknown. We hypothesized that augmenting synaptic signaling during retrieval would increase memory lability. To enhance synaptic transmission, mice inhaled CO2 to induce an acidosis and activate acid sensing ion channels. Transient acidification increased the retrieval-induced lability of an aversive memory. The labile memory could then be weakened by an extinction protocol or strengthened by reconditioning. Coupling CO2 inhalation to retrieval increased activation of amygdala neurons bearing the memory trace and increased the synaptic exchange from Ca2+-impermeable to Ca2+-permeable AMPA receptors. The results suggest that transient acidosis during retrieval renders the memory of an aversive event more labile and suggest a strategy to modify debilitating memories. DOI: http://dx.doi.org/10.7554/eLife.22564.001 PMID:28650315

How Does the Sparse Memory “Engram” Neurons Encode the Memory of a Spatial–Temporal Event?

PubMed Central

Guan, Ji-Song; Jiang, Jun; Xie, Hong; Liu, Kai-Yuan

2016-01-01

Episodic memory in human brain is not a fixed 2-D picture but a highly dynamic movie serial, integrating information at both the temporal and the spatial domains. Recent studies in neuroscience reveal that memory storage and recall are closely related to the activities in discrete memory engram (trace) neurons within the dentate gyrus region of hippocampus and the layer 2/3 of neocortex. More strikingly, optogenetic reactivation of those memory trace neurons is able to trigger the recall of naturally encoded memory. It is still unknown how the discrete memory traces encode and reactivate the memory. Considering a particular memory normally represents a natural event, which consists of information at both the temporal and spatial domains, it is unknown how the discrete trace neurons could reconstitute such enriched information in the brain. Furthermore, as the optogenetic-stimuli induced recall of memory did not depend on firing pattern of the memory traces, it is most likely that the spatial activation pattern, but not the temporal activation pattern of the discrete memory trace neurons encodes the memory in the brain. How does the neural circuit convert the activities in the spatial domain into the temporal domain to reconstitute memory of a natural event? By reviewing the literature, here we present how the memory engram (trace) neurons are selected and consolidated in the brain. Then, we will discuss the main challenges in the memory trace theory. In the end, we will provide a plausible model of memory trace cell network, underlying the conversion of neural activities between the spatial domain and the temporal domain. We will also discuss on how the activation of sparse memory trace neurons might trigger the replay of neural activities in specific temporal patterns. PMID:27601979

How Does the Sparse Memory "Engram" Neurons Encode the Memory of a Spatial-Temporal Event?

PubMed

Guan, Ji-Song; Jiang, Jun; Xie, Hong; Liu, Kai-Yuan

2016-01-01

Episodic memory in human brain is not a fixed 2-D picture but a highly dynamic movie serial, integrating information at both the temporal and the spatial domains. Recent studies in neuroscience reveal that memory storage and recall are closely related to the activities in discrete memory engram (trace) neurons within the dentate gyrus region of hippocampus and the layer 2/3 of neocortex. More strikingly, optogenetic reactivation of those memory trace neurons is able to trigger the recall of naturally encoded memory. It is still unknown how the discrete memory traces encode and reactivate the memory. Considering a particular memory normally represents a natural event, which consists of information at both the temporal and spatial domains, it is unknown how the discrete trace neurons could reconstitute such enriched information in the brain. Furthermore, as the optogenetic-stimuli induced recall of memory did not depend on firing pattern of the memory traces, it is most likely that the spatial activation pattern, but not the temporal activation pattern of the discrete memory trace neurons encodes the memory in the brain. How does the neural circuit convert the activities in the spatial domain into the temporal domain to reconstitute memory of a natural event? By reviewing the literature, here we present how the memory engram (trace) neurons are selected and consolidated in the brain. Then, we will discuss the main challenges in the memory trace theory. In the end, we will provide a plausible model of memory trace cell network, underlying the conversion of neural activities between the spatial domain and the temporal domain. We will also discuss on how the activation of sparse memory trace neurons might trigger the replay of neural activities in specific temporal patterns.

Short-Term Memory Trace in Rapidly Adapting Synapses of Inferior Temporal Cortex

PubMed Central

Sugase-Miyamoto, Yasuko; Liu, Zheng; Wiener, Matthew C.; Optican, Lance M.; Richmond, Barry J.

2008-01-01

Visual short-term memory tasks depend upon both the inferior temporal cortex (ITC) and the prefrontal cortex (PFC). Activity in some neurons persists after the first (sample) stimulus is shown. This delay-period activity has been proposed as an important mechanism for working memory. In ITC neurons, intervening (nonmatching) stimuli wipe out the delay-period activity; hence, the role of ITC in memory must depend upon a different mechanism. Here, we look for a possible mechanism by contrasting memory effects in two architectonically different parts of ITC: area TE and the perirhinal cortex. We found that a large proportion (80%) of stimulus-selective neurons in area TE of macaque ITCs exhibit a memory effect during the stimulus interval. During a sequential delayed matching-to-sample task (DMS), the noise in the neuronal response to the test image was correlated with the noise in the neuronal response to the sample image. Neurons in perirhinal cortex did not show this correlation. These results led us to hypothesize that area TE contributes to short-term memory by acting as a matched filter. When the sample image appears, each TE neuron captures a static copy of its inputs by rapidly adjusting its synaptic weights to match the strength of their individual inputs. Input signals from subsequent images are multiplied by those synaptic weights, thereby computing a measure of the correlation between the past and present inputs. The total activity in area TE is sufficient to quantify the similarity between the two images. This matched filter theory provides an explanation of what is remembered, where the trace is stored, and how comparison is done across time, all without requiring delay period activity. Simulations of a matched filter model match the experimental results, suggesting that area TE neurons store a synaptic memory trace during short-term visual memory. PMID:18464917

Deeper processing is beneficial during episodic memory encoding for adults with Williams syndrome.

PubMed

Greer, Joanna; Hamiliton, Colin; Riby, Deborah M; Riby, Leigh M

2014-07-01

Previous research exploring declarative memory in Williams syndrome (WS) has revealed impairment in the processing of episodic information accompanied by a relative strength in semantic ability. The aim of the current study was to extend this literature by examining how relatively spared semantic memory may support episodic remembering. Using a level of processing paradigm, older adults with WS (aged 35-61 years) were compared to typical adults of the same chronological age and typically developing children matched for verbal ability. In the study phase, pictures were encoded using either a deep (decide if a picture belongs to a particular category) or shallow (perceptual based processing) memory strategy. Behavioural indices (reaction time and accuracy) at retrieval were suggestive of an overall difficulty in episodic memory for WS adults. Interestingly, however, semantic support was evident with a greater recall of items encoded with deep compared to shallow processing, indicative of an ability to employ semantic encoding strategies to maximise the strength of the memory trace created. Unlike individuals with autism who find semantic elaboration strategies problematic, the pattern of findings reported here suggests in those domains that are relatively impaired in WS, support can be recruited from relatively spared cognitive processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

A dual-trace model for visual sensory memory.

PubMed

Cappiello, Marcus; Zhang, Weiwei

2016-11-01

Visual sensory memory refers to a transient memory lingering briefly after the stimulus offset. Although previous literature suggests that visual sensory memory is supported by a fine-grained trace for continuous representation and a coarse-grained trace of categorical information, simultaneous separation and assessment of these traces can be difficult without a quantitative model. The present study used a continuous estimation procedure to test a novel mathematical model of the dual-trace hypothesis of visual sensory memory according to which visual sensory memory could be modeled as a mixture of 2 von Mises (2VM) distributions differing in standard deviation. When visual sensory memory and working memory (WM) for colors were distinguished using different experimental manipulations in the first 3 experiments, the 2VM model outperformed Zhang and Luck (2008) standard mixture model (SM) representing a mixture of a single memory trace and random guesses, even though SM outperformed 2VM for WM. Experiment 4 generalized 2VM's advantages of fitting visual sensory memory data over SM from color to orientation. Furthermore, a single trace model and 4 other alternative models were ruled out, suggesting the necessity and sufficiency of dual traces for visual sensory memory. Together these results support the dual-trace model of visual sensory memory and provide a preliminary inquiry into the nature of information loss from visual sensory memory to WM. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Categorical and associative relations increase false memory relative to purely associative relations.

PubMed

Coane, Jennifer H; McBride, Dawn M; Termonen, Miia-Liisa; Cutting, J Cooper

2016-01-01

The goal of the present study was to examine the contributions of associative strength and similarity in terms of shared features to the production of false memories in the Deese/Roediger-McDermott list-learning paradigm. Whereas the activation/monitoring account suggests that false memories are driven by automatic associative activation from list items to nonpresented lures, combined with errors in source monitoring, other accounts (e.g., fuzzy trace theory, global-matching models) emphasize the importance of semantic-level similarity, and thus predict that shared features between list and lure items will increase false memory. Participants studied lists of nine items related to a nonpresented lure. Half of the lists consisted of items that were associated but did not share features with the lure, and the other half included items that were equally associated but also shared features with the lure (in many cases, these were taxonomically related items). The two types of lists were carefully matched in terms of a variety of lexical and semantic factors, and the same lures were used across list types. In two experiments, false recognition of the critical lures was greater following the study of lists that shared features with the critical lure, suggesting that similarity at a categorical or taxonomic level contributes to false memory above and beyond associative strength. We refer to this phenomenon as a "feature boost" that reflects additive effects of shared meaning and association strength and is generally consistent with accounts of false memory that have emphasized thematic or feature-level similarity among studied and nonstudied representations.

The strength of aversive and appetitive associations and maladaptive behaviors.

PubMed

Itzhak, Yossef; Perez-Lanza, Daniel; Liddie, Shervin

2014-08-01

Certain maladaptive behaviors are thought to be acquired through classical Pavlovian conditioning. Exaggerated fear response, which can develop through Pavlovian conditioning, is associated with acquired anxiety disorders such as post-traumatic stress disorders (PTSDs). Inflated reward-seeking behavior, which develops through Pavlovian conditioning, underlies some types of addictive behavior (e.g., addiction to drugs, food, and gambling). These maladaptive behaviors are dependent on associative learning and the development of long-term memory (LTM). In animal models, an aversive reinforcer (fear conditioning) encodes an aversive contextual and cued LTM. On the other hand, an appetitive reinforcer results in conditioned place preference (CPP) that encodes an appetitive contextual LTM. The literature on weak and strong associative learning pertaining to the development of aversive and appetitive LTM is relatively scarce; thus, this review is particularly focused on the strength of associative learning. The strength of associative learning is dependent on the valence of the reinforcer and the salience of the conditioned stimulus that ultimately sways the strength of the memory trace. Our studies suggest that labile (weak) aversive and appetitive LTM may share similar signaling pathways, whereas stable (strong) aversive and appetitive LTM is mediated through different pathways. In addition, we provide some evidence suggesting that extinction of aversive fear memory and appetitive drug memory is likely to be mediated through different signaling molecules. We put forward the importance of studies aimed to investigate the molecular mechanisms underlying the development of weak and strong memories (aversive and appetitive), which would ultimately help in the development of targeted pharmacotherapies for the management of maladaptive behaviors that arise from classical Pavlovian conditioning. © 2014 International Union of Biochemistry and Molecular Biology.

Gamma-band activation predicts both associative memory and cortical plasticity

PubMed Central

Headley, Drew B.; Weinberger, Norman M.

2011-01-01

Gamma-band oscillations are a ubiquitous phenomenon in the nervous system and have been implicated in multiple aspects of cognition. In particular, the strength of gamma oscillations at the time a stimulus is encoded predicts its subsequent retrieval, suggesting that gamma may reflect enhanced mnemonic processing. Likewise, activity in the gamma-band can modulate plasticity in vitro. However, it is unclear whether experience-dependent plasticity in vivo is also related to gamma-band activation. The aim of the present study is to determine whether gamma activation in primary auditory cortex modulates both the associative memory for an auditory stimulus during classical conditioning and its accompanying specific receptive field plasticity. Rats received multiple daily sessions of single tone/shock trace and two-tone discrimination conditioning, during which local field potentials and multiunit discharges were recorded from chronically implanted electrodes. We found that the strength of tone-induced gamma predicted the acquisition of associative memory 24 h later, and ceased to predict subsequent performance once asymptote was reached. Gamma activation also predicted receptive field plasticity that specifically enhanced representation of the signal tone. This concordance provides a long-sought link between gamma oscillations, cortical plasticity and the formation of new memories. PMID:21900554

Traces of Drosophila Memory

PubMed Central

Davis, Ronald L.

2012-01-01

Summary Studies using functional cellullar imaging of living flies have identified six memory traces that form in the olfactory nervous system after conditioning with odors. These traces occur in distinct nodes of the olfactory nervous system, form and disappear across different windows of time, and are detected in the imaged neurons as increased calcium influx or synaptic release in response to the conditioned odor. Three traces form at, or near acquisition and co-exist with short-term behavioral memory. One trace forms with a delay after learning and co-exists with intermediate-term behavioral memory. Two traces form many hours after acquisition and co-exist with long-term behavioral memory. The transient memory traces may support behavior across the time-windows of their existence. The experimental approaches for dissecting memory formation in the fly, ranging from the molecular to the systems, make it an ideal system for dissecting the logic by which the nervous system organizes and stores different temporal forms of memory. PMID:21482352

The role of working memory and declarative memory in trace conditioning

PubMed Central

Connor, David A.; Gould, Thomas J.

2017-01-01

Translational assays of cognition that are similarly implemented in both lower and higher-order species, such as rodents and primates, provide a means to reconcile preclinical modeling of psychiatric neuropathology and clinical research. To this end, Pavlovian conditioning has provided a useful tool for investigating cognitive processes in both lab animal models and humans. This review focuses on trace conditioning, a form of Pavlovian conditioning typified by the insertion of a temporal gap (i.e., trace interval) between presentations of a conditioned stimulus (CS) and an unconditioned stimulus (US). This review aims to discuss pre-clinical and clinical work investigating the mnemonic processes recruited for trace conditioning. Much work suggests that trace conditioning involves unique neurocognitive mechanisms to facilitate formation of trace memories in contrast to standard Pavlovian conditioning. For example, the hippocampus and prefrontal cortex (PFC) appear to play critical roles in trace conditioning. Moreover, cognitive mechanistic accounts in human studies suggest that working memory and declarative memory processes are engaged to facilitate formation of trace memories. The aim of this review is to integrate cognitive and neurobiological accounts of trace conditioning from preclinical and clinical studies to examine involvement of working and declarative memory. PMID:27422017

Expectancies as a Determinant of Interference Phenomena

ERIC Educational Resources Information Center

Hasher, Lynn; Greenberg, Michael

1977-01-01

One version, by Lockhart, Craik, and Jacoby, of a levels-of-processing model of memory asserts the importance of the role of expectancies about forthcoming information in determining the elaborateness of a memory trace. Confirmed expectancies result in less-elaborated memory traces; disconfirmed expectancies result in elaborate memory traces.…

Memories Are Made of This.

ERIC Educational Resources Information Center

Fox, Jeffrey L.

1983-01-01

Provides comments on research studies related to memory systems, considering those exploring the nature of memory traces. One researcher suggests that memory trace circuits are extremely localized (as opposed to being diffuse), such that a lesion in a rabbit's brain can completely destroy the trace for a particular learned response. (JN)

How Fuzzy-Trace Theory Predicts True and False Memories for Words, Sentences, and Narratives

PubMed Central

Reyna, Valerie F.; Corbin, Jonathan C.; Weldon, Rebecca B.; Brainerd, Charles J.

2016-01-01

Fuzzy-trace theory posits independent verbatim and gist memory processes, a distinction that has implications for such applied topics as eyewitness testimony. This distinction between precise, literal verbatim memory and meaning-based, intuitive gist accounts for memory paradoxes including dissociations between true and false memory, false memories outlasting true memories, and developmental increases in false memory. We provide an overview of fuzzy-trace theory, and, using mathematical modeling, also present results demonstrating verbatim and gist memory in true and false recognition of narrative sentences and inferences. Results supported fuzzy-trace theory's dual-process view of memory: verbatim memory was relied on to reject meaning-consistent, but unpresented, sentences (via recollection rejection). However, verbatim memory was often not retrieved, and gist memory supported acceptance of these sentences (via similarity judgment and phantom recollection). Thus, mathematical models of words can be extended to explain memory for complex stimuli, such as narratives, the kind of memory interrogated in law. PMID:27042402

Address tracing for parallel machines

NASA Technical Reports Server (NTRS)

Stunkel, Craig B.; Janssens, Bob; Fuchs, W. Kent

1991-01-01

Recently implemented parallel system address-tracing methods based on several metrics are surveyed. The issues specific to collection of traces for both shared and distributed memory parallel computers are highlighted. Five general categories of address-trace collection methods are examined: hardware-captured, interrupt-based, simulation-based, altered microcode-based, and instrumented program-based traces. The problems unique to shared memory and distributed memory multiprocessors are examined separately.

Ad hoc categories and false memories: Memory illusions for categories created on-the-spot.

PubMed

Soro, Jerônimo C; Ferreira, Mário B; Semin, Gün R; Mata, André; Carneiro, Paula

2017-11-01

Three experiments were designed to test whether experimentally created ad hoc associative networks evoke false memories. We used the DRM (Deese, Roediger, McDermott) paradigm with lists of ad hoc categories composed of exemplars aggregated toward specific goals (e.g., going for a picnic) that do not share any consistent set of features. Experiment 1 revealed considerable levels of false recognitions of critical words from ad hoc categories. False recognitions occurred even when the lists were presented without an organizing theme (i.e., the category's label). Experiments 1 and 2 tested whether (a) the ease of identifying the categories' themes, and (b) the lists' backward associative strength could be driving the effect. List identifiability did not correlate with false recognition, and the effect remained even when backward associative strength was controlled for. Experiment 3 manipulated the distractor items in the recognition task to address the hypothesis that the salience of unrelated items could be facilitating the occurrence of the phenomenon. The effect remained when controlling for this source of facilitation. These results have implications for assumptions made by theories of false memories, namely the preexistence of associations in the activation-monitoring framework and the central role of gist extraction in fuzzy-trace theory, while providing evidence of the occurrence of false memories for more dynamic and context-dependent knowledge structures. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Stress enhances reconsolidation of declarative memory.

PubMed

Bos, Marieke G N; Schuijer, Jantien; Lodestijn, Fleur; Beckers, Tom; Kindt, Merel

2014-08-01

Retrieval of negative emotional memories is often accompanied by the experience of stress. Upon retrieval, a memory trace can temporarily return into a labile state, where it is vulnerable to change. An unresolved question is whether post-retrieval stress may affect the strength of declarative memory in humans by modulating the reconsolidation process. Here, we tested in two experiments whether post-reactivation stress may affect the strength of declarative memory in humans. In both experiments, participants were instructed to learn neutral, positive and negative words. Approximately 24h later, participants received a reminder of the word list followed by exposure to the social evaluative cold pressor task (reactivation/stress group, nexp1=20; nexp2=18) or control task (reactivation/no-stress group, nexp1=23; nexp2=18). An additional control group was solely exposed to the stress task, without memory reactivation (no-reactivation/stress group, nexp1=23; nexp2=21). The next day, memory performance was tested using a free recall and a recognition task. In the first experiment we showed that participants in the reactivation/stress group recalled more words than participants in the reactivation/no-stress and no-reactivation/stress group, irrespective of valence of the word stimuli. Furthermore, participants in the reactivation/stress group made more false recognition errors. In the second experiment we replicated our observations on the free recall task for a new set of word stimuli, but we did not find any differences in false recognition. The current findings indicate that post-reactivation stress can improve declarative memory performance by modulating the process of reconsolidation. This finding contributes to our understanding why some memories are more persistent than others. Copyright © 2014. Published by Elsevier Ltd.

Analysis of memory use for improved design and compile-time allocation of local memory

NASA Technical Reports Server (NTRS)

Mcniven, Geoffrey D.; Davidson, Edward S.

1986-01-01

Trace analysis techniques are used to study memory referencing behavior for the purpose of designing local memories and determining how to allocate them for data and instructions. In an attempt to assess the inherent behavior of the source code, the trace analysis system described here reduced the effects of the compiler and host architecture on the trace by using a technical called flattening. The variables in the trace, their associated single-assignment values, and references are histogrammed on the basis of various parameters describing memory referencing behavior. Bounds are developed specifying the amount of memory space required to store all live values in a particular histogram class. The reduction achieved in main memory traffic by allocating local memory is specified for each class.

Tests of a Structural Theory of the Memory Trace.

ERIC Educational Resources Information Center

Jones, Gregory V.

1978-01-01

Jones (1976) has shown that the memory trace resulting from the viewing of a picture corresponds to a "fragment" of that picture. This research shows that the fragmentation hypothesis also correctly represents the recall of memories derived from sentences, i.e., the functional unit of memory, the mnemonic trace, is a fragment of the original item.…

Fuzzy-Trace Theory and False Memory: New Frontiers.

ERIC Educational Resources Information Center

Reyna, Valerie F.; Brainerd, C. J.

1998-01-01

Describes the origins of fuzzy-trace theory, including Piagetian, interference, information-processing, and judgment and decision-making influences. Discusses similarities and differences between fuzzy-trace theory and other approaches to memory falsification. Considers the theory's predictions regarding age differences in memory falsification and…

Environmental cue saliency influences the vividness of a remote spatial memory in rats.

PubMed

Lopez, Joëlle; de Vasconcelos, Anne Pereira; Cassel, Jean-Christophe

2008-07-01

The Morris water maze is frequently used to evaluate the acquisition and retrieval of spatial memories. Few experiments, however, have investigated the effects of environmental cue saliency on the strength or persistence of such memories after a short vs. long post-acquisition interval. Using a Morris water maze, we therefore tested in rats the effect of the saliency of distal cues on the vividness of a recent (5 days) vs. remote (25 days) memory. Rats trained in a cue-enriched vs. a cue-impoverished context showed a better overall level of performance during acquisition. Furthermore, the probe trials revealed that the rats trained and tested in the cue-impoverished context (1) spent less time in the target quadrant at the 25-day delay, and (2) swam shorter distances in the target area, with fewer crossings at both 5- and 25-day delays, as compared to their counterparts trained and tested in the cue-enriched context. Thus, the memory trace formed in the cue-enriched context shows better resistance to time, suggesting an implication of cue saliency in the vividness of a spatial memory.

Hierarchical Traces for Reduced NSM Memory Requirements

NASA Astrophysics Data System (ADS)

Dahl, Torbjørn S.

This paper presents work on using hierarchical long term memory to reduce the memory requirements of nearest sequence memory (NSM) learning, a previously published, instance-based reinforcement learning algorithm. A hierarchical memory representation reduces the memory requirements by allowing traces to share common sub-sequences. We present moderated mechanisms for estimating discounted future rewards and for dealing with hidden state using hierarchical memory. We also present an experimental analysis of how the sub-sequence length affects the memory compression achieved and show that the reduced memory requirements do not effect the speed of learning. Finally, we analyse and discuss the persistence of the sub-sequences independent of specific trace instances.

Distributed trace using central performance counter memory

DOEpatents

Satterfield, David L; Sexton, James C

2013-10-22

A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

Distributed trace using central performance counter memory

DOEpatents

Satterfield, David L.; Sexton, James C.

2013-01-22

A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

A single-trace dual-process model of episodic memory: a novel computational account of familiarity and recollection.

PubMed

Greve, Andrea; Donaldson, David I; van Rossum, Mark C W

2010-02-01

Dual-process theories of episodic memory state that retrieval is contingent on two independent processes: familiarity (providing a sense of oldness) and recollection (recovering events and their context). A variety of studies have reported distinct neural signatures for familiarity and recollection, supporting dual-process theory. One outstanding question is whether these signatures reflect the activation of distinct memory traces or the operation of different retrieval mechanisms on a single memory trace. We present a computational model that uses a single neuronal network to store memory traces, but two distinct and independent retrieval processes access the memory. The model is capable of performing familiarity and recollection-based discrimination between old and new patterns, demonstrating that dual-process models need not to rely on multiple independent memory traces, but can use a single trace. Importantly, our putative familiarity and recollection processes exhibit distinct characteristics analogous to those found in empirical data; they diverge in capacity and sensitivity to sparse and correlated patterns, exhibit distinct ROC curves, and account for performance on both item and associative recognition tests. The demonstration that a single-trace, dual-process model can account for a range of empirical findings highlights the importance of distinguishing between neuronal processes and the neuronal representations on which they operate.

Neural population-level memory traces in the mouse hippocampus.

PubMed

Chen, Guifen; Wang, L Phillip; Tsien, Joe Z

2009-12-16

One of the fundamental goals in neurosciences is to elucidate the formation and retrieval of brain's associative memory traces in real-time. Here, we describe real-time neural ensemble transient dynamics in the mouse hippocampal CA1 region and demonstrate their relationships with behavioral performances during both learning and recall. We employed the classic trace fear conditioning paradigm involving a neutral tone followed by a mild foot-shock 20 seconds later. Our large-scale recording and decoding methods revealed that conditioned tone responses and tone-shock association patterns were not present in CA1 during the first pairing, but emerged quickly after multiple pairings. These encoding patterns showed increased immediate-replay, correlating tightly with increased immediate-freezing during learning. Moreover, during contextual recall, these patterns reappeared in tandem six-to-fourteen times per minute, again correlating tightly with behavioral recall. Upon traced tone recall, while various fear memories were retrieved, the shock traces exhibited a unique recall-peak around the 20-second trace interval, further signifying the memory of time for the expected shock. Therefore, our study has revealed various real-time associative memory traces during learning and recall in CA1, and demonstrates that real-time memory traces can be decoded on a moment-to-moment basis over any single trial.

Stability of retrieved memory: inverse correlation with trace dominance.

PubMed

Eisenberg, Mark; Kobilo, Tali; Berman, Diego E; Dudai, Yadin

2003-08-22

In memory consolidation, the memory trace stabilizes and becomes resistant to certain amnesic agents. The textbook account is that for any memorized item, consolidation starts and ends just once. However, evidence has accumulated that upon activation in retrieval, the trace may reconsolidate. Whereas some authors reported transient renewed susceptibility of retrieved memories to consolidation blockers, others could not detect it. Here, we report that in both conditioned taste aversion in the rat and fear conditioning in the medaka fish, the stability of retrieved memory is inversely correlated with the control of behavior by that memory. This result may explain some conflicting findings on reconsolidation of activated memories.

Improved specificity of hippocampal memory trace labeling.

PubMed

Cazzulino, Alejandro S; Martinez, Randy; Tomm, Nicole K; Denny, Christine A

2016-06-01

Recent studies have focused on the identification and manipulation of memory traces in rodent models. The two main mouse models utilized are either a CreER(T2) /loxP tamoxifen (TAM)- or a tetracycline transactivator/tetracycline-response element doxycycline-inducible system. These systems, however, could be improved to label a more specific population of activated neurons corresponding to behavior. Here, we sought to identify an improved selective estrogen receptor (ER) modulator (SERM) in which we could label an individual memory trace in ArcCreER(T2) mice. We found that 4-hydroxytamoxifen (4-OHT) is a selective SERM in the ArcCreER(T2) × Rosa26-CAG-stop(flox) -channelrhodospin (ChR2)-enhanced yellow fluorescent protein (eYFP) mice. The half-life of 4-OHT is shorter than TAM, allowing for more specificity of memory trace labeling. Furthermore, 4-OHT allowed for context-specific labeling in the dentate gyrus and CA3. In summary, we believe that 4-OHT improves the specificity of memory trace labeling and will allow for refined memory trace studies in the future. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Optimization of immunolabeling and clearing techniques for indelibly-labeled memory traces.

PubMed

Pavlova, Ina P; Shipley, Shannon C; Lanio, Marcos; Hen, René; Denny, Christine A

2018-04-16

Recent genetic tools have allowed researchers to visualize and manipulate memory traces (i.e. engrams) in small brain regions. However, the ultimate goal is to visualize memory traces across the entire brain in order to better understand how memories are stored in neural networks and how multiple memories may coexist. Intact tissue clearing and imaging is a new and rapidly growing area of focus that could accomplish this task. Here, we utilized the leading protocols for whole-brain clearing and applied them to the ArcCreER T2 mice, a murine line that allows for the indelible labeling of memory traces. We found that CLARITY and PACT greatly distorted the tissue, and iDISCO quenched enhanced yellow fluorescent protein (EYFP) fluorescence and hindered immunolabeling. Alternative clearing solutions, such as tert-Butanol, circumvented these harmful effects, but still did not permit whole-brain immunolabeling. CUBIC and CUBIC with Reagent 1A produced improved antibody penetration and preserved EYFP fluorescence, but also did not allow for whole-brain memory trace visualization. Modification of CUBIC with Reagent-1A resulted in EYFP fluorescence preservation and immunolabeling of the immediate early gene (IEG) Arc in deep brain areas; however, optimized memory trace labeling still required tissue slicing into mm-thick tissue sections. In summary, our data show that CUBIC with Reagent-1A* is the ideal method for reproducible clearing and immunolabeling for the visualization of memory traces in mm-thick tissue sections from ArcCreER T2 mice. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Effects of Trace Amine-associated Receptor 1 Agonists on the Expression, Reconsolidation, and Extinction of Cocaine Reward Memory.

PubMed

Liu, Jian-Feng; Thorn, David A; Zhang, Yanan; Li, Jun-Xu

2016-07-01

As a modulator of dopaminergic system, trace amine-associated receptor 1 has been shown to play a critical role in regulating the rewarding properties of additive drugs. It has been demonstrated that activation of trace amine-associated receptor 1 decreased the abuse-related behaviors of cocaine in rats. However, the role of trace amine-associated receptor 1 in specific stages of cocaine reward memory is still unclear. Here, using a cocaine-induced conditioned place preference model, we tested the effects of a selective trace amine-associated receptor 1 agonist RO5166017 on the expression, reconsolidation, and extinction of cocaine reward memory. We found that RO5166017 inhibited the expression but not retention of cocaine-induced conditioned place preference. RO5166017 had no effect on the reconsolidation of cocaine reward memory. Pretreatment with RO5166017 before extinction hindered the formation of extinction long-term memory. RO5166017 did not affect the movement during the conditioned place preference test, indicating the inhibitory effect of RO5166017 on the expression of cocaine-induced conditioned place preference was not caused by locomotion inhibition. Using a cocaine i.v. self-administration model, we found that the combined trace amine-associated receptor 1 partial agonist RO5263397 with extinction had no effect on the following cue- and drug-induced reinstatement of cocaine-seeking behavior. Repeated administration of the trace amine-associated receptor 1 agonist during extinction showed a continually inhibitory effect on the expression of cocaine reward memory both in cocaine-induced conditioned place preference and cocaine self-administration models. Taken together, these results indicate that activation of trace amine-associated receptor 1 specifically inhibited the expression of cocaine reward memory. The inhibitory effect of trace amine-associated receptor 1 agonists on cocaine reward memory suggests that trace amine-associated receptor 1 agonists could be a promising agent to prevent cocaine relapse. © The Author 2016. Published by Oxford University Press on behalf of CINP.

Are memory traces localized or distributed?

PubMed

Thompson, R F

1991-01-01

Evidence supports the view that "memory traces" are formed in the hippocampus and in the cerebellum in classical conditioning of discrete behavioral responses (e.g. eyeblink conditioning). In the hippocampus, learning results in long-lasting increases in excitability of pyramidal neurons that appear to be localized to these neurons (i.e. changes in membrane properties and receptor function). However, these learning-altered pyramidal neurons are distributed widely throughout CA3 and CA1. Although it plays a key role in certain aspects of classical conditioning, the hippocampus is not necessary for learning and memory of the basic conditioned responses. The cerebellum and its associated brain stem circuitry, on the other hand, does appear to be essential (necessary and sufficient) for learning and memory of the conditioned response. Evidence to date is most consistent with a localized trace in the interpositus nucleus and multiple localized traces in cerebellar cortex, each involving relatively large ensembles of neurons. Perhaps "procedural" memory traces are relatively localized and "declarative" traces more widely distributed.

Mapping and Deciphering Neural Codes of NMDA Receptor-Dependent Fear Memory Engrams in the Hippocampus

PubMed Central

Tsien, Joe Z.

2013-01-01

Mapping and decoding brain activity patterns underlying learning and memory represents both great interest and immense challenge. At present, very little is known regarding many of the very basic questions regarding the neural codes of memory: are fear memories retrieved during the freezing state or non-freezing state of the animals? How do individual memory traces give arise to a holistic, real-time associative memory engram? How are memory codes regulated by synaptic plasticity? Here, by applying high-density electrode arrays and dimensionality-reduction decoding algorithms, we investigate hippocampal CA1 activity patterns of trace fear conditioning memory code in inducible NMDA receptor knockout mice and their control littermates. Our analyses showed that the conditioned tone (CS) and unconditioned foot-shock (US) can evoke hippocampal ensemble responses in control and mutant mice. Yet, temporal formats and contents of CA1 fear memory engrams differ significantly between the genotypes. The mutant mice with disabled NMDA receptor plasticity failed to generate CS-to-US or US-to-CS associative memory traces. Moreover, the mutant CA1 region lacked memory traces for “what at when” information that predicts the timing relationship between the conditioned tone and the foot shock. The degraded associative fear memory engram is further manifested in its lack of intertwined and alternating temporal association between CS and US memory traces that are characteristic to the holistic memory recall in the wild-type animals. Therefore, our study has decoded real-time memory contents, timing relationship between CS and US, and temporal organizing patterns of fear memory engrams and demonstrated how hippocampal memory codes are regulated by NMDA receptor synaptic plasticity. PMID:24302990

The influence of the substrate on the adhesive strength of the micro-arc oxidation coating developed on TiNi shape memory alloy

NASA Astrophysics Data System (ADS)

Hsieh, Shy-Feng; Ou, Shih-Fu; Chou, Chia-Kai

2017-01-01

TiNi shape memory alloys (SMAs), used as long-term implant materials, have a disadvantage. Ni-ion release from the alloys may trigger allergies in the human body. Micro-arc oxidation has been utilized to modify the surface of the TiNi SMA for improving its corrosion resistance and biocompatibility. However, there are very few reports investigating the essential adhesive strength between the micro-arc oxidized film and TiNi SMA. Two primary goals were attained by this study. First, Ti50Ni48.5Mo1.5 SMA having a phase transformation temperature (Af) less than body temperature and good shape recovery were prepared. Next, the Ti50Ni50 and Ti50Ni48.5Mo1.5 SMA surfaces were modified by micro-arc oxidation in phosphoric acid by applying relatively low voltages to maintain the adhesive strength. The results indicated that the pore size, film thickness, and P content increased with applied voltage. The micro-arc oxidized film, comprising Ti oxides, Ni oxide, and phosphate compounds, exhibited a glassy amorphous structure. The outmost surface of the micro-arc oxidized film contained a large amount of P (>12 at%) but only a trace of Ni (<5 at%). The adhesive strengths of all the micro-arc oxidized films exceeded the requirements of ISO 13779. Furthermore, Mo addition into TiNi SMAs was found to be favorable for improving the adhesive strength of the micro-arc oxidized film.

Comparing single- and dual-process models of memory development.

PubMed

Hayes, Brett K; Dunn, John C; Joubert, Amy; Taylor, Robert

2017-11-01

This experiment examined single-process and dual-process accounts of the development of visual recognition memory. The participants, 6-7-year-olds, 9-10-year-olds and adults, were presented with a list of pictures which they encoded under shallow or deep conditions. They then made recognition and confidence judgments about a list containing old and new items. We replicated the main trends reported by Ghetti and Angelini () in that recognition hit rates increased from 6 to 9 years of age, with larger age changes following deep than shallow encoding. Formal versions of the dual-process high threshold signal detection model and several single-process models (equal variance signal detection, unequal variance signal detection, mixture signal detection) were fit to the developmental data. The unequal variance and mixture signal detection models gave a better account of the data than either of the other models. A state-trace analysis found evidence for only one underlying memory process across the age range tested. These results suggest that single-process memory models based on memory strength are a viable alternative to dual-process models for explaining memory development. © 2016 John Wiley & Sons Ltd.

Competitive Trace Theory: A Role for the Hippocampus in Contextual Interference during Retrieval.

PubMed

Yassa, Michael A; Reagh, Zachariah M

2013-01-01

Much controversy exists regarding the role of the hippocampus in retrieval. The two dominant and competing accounts have been the Standard Model of Systems Consolidation (SMSC) and Multiple Trace Theory (MTT), which specifically make opposing predictions as to the necessity of the hippocampus for retrieval of remote memories. Under SMSC, memories eventually become independent of the hippocampus as they become more reliant on cortical connectivity, and thus the hippocampus is not required for retrieval of remote memories, only recent ones. MTT on the other hand claims that the hippocampus is always required no matter the age of the memory. We argue that this dissociation may be too simplistic, and a continuum model may be better suited to address the role of the hippocampus in retrieval of remote memories. Such a model is presented here with the main function of the hippocampus during retrieval being "recontextualization," or the reconstruction of memory using overlapping traces. As memories get older, they are decontextualized due to competition among partially overlapping traces and become more semantic and reliant on neocortical storage. In this framework dubbed the Competitive Trace Theory (CTT), consolidation events that lead to the strengthening of memories enhance conceptual knowledge (semantic memory) at the expense of contextual details (episodic memory). As a result, remote memories are more likely to have a stronger semantic representation. At the same time, remote memories are also more likely to include illusory details. The CTT is a novel candidate model that may provide some resolution to the memory consolidation debate.

Competitive Trace Theory: A Role for the Hippocampus in Contextual Interference during Retrieval

PubMed Central

Yassa, Michael A.; Reagh, Zachariah M.

2013-01-01

Much controversy exists regarding the role of the hippocampus in retrieval. The two dominant and competing accounts have been the Standard Model of Systems Consolidation (SMSC) and Multiple Trace Theory (MTT), which specifically make opposing predictions as to the necessity of the hippocampus for retrieval of remote memories. Under SMSC, memories eventually become independent of the hippocampus as they become more reliant on cortical connectivity, and thus the hippocampus is not required for retrieval of remote memories, only recent ones. MTT on the other hand claims that the hippocampus is always required no matter the age of the memory. We argue that this dissociation may be too simplistic, and a continuum model may be better suited to address the role of the hippocampus in retrieval of remote memories. Such a model is presented here with the main function of the hippocampus during retrieval being “recontextualization,” or the reconstruction of memory using overlapping traces. As memories get older, they are decontextualized due to competition among partially overlapping traces and become more semantic and reliant on neocortical storage. In this framework dubbed the Competitive Trace Theory (CTT), consolidation events that lead to the strengthening of memories enhance conceptual knowledge (semantic memory) at the expense of contextual details (episodic memory). As a result, remote memories are more likely to have a stronger semantic representation. At the same time, remote memories are also more likely to include illusory details. The CTT is a novel candidate model that may provide some resolution to the memory consolidation debate. PMID:23964216

The origin of children's implanted false memories: memory traces or compliance?

PubMed

Otgaar, Henry; Verschuere, Bruno; Meijer, Ewout H; van Oorsouw, Kim

2012-03-01

A longstanding question in false memory research is whether children's implanted false memories represent actual memory traces or merely result from compliance. The current study examined this question using a response latency based deception task. Forty-five 8-year-old children received narratives about a true (first day at school) and false event (hot air balloon ride). Across two interviews, 58/32% of the participants developed a partial/full false memory. Interestingly, these children also showed higher false recall on an unrelated DRM paradigm compared to children without a false memory. The crucial finding, however, was that the results of the deception task revealed that children with partial and full false memories were faster to confirm than to deny statements relating to the false event. This indicates that children's implanted false memories reflect actual memory traces, and are unlikely to be explained by mere compliance. Copyright © 2012 Elsevier B.V. All rights reserved.

Goal-Driven Autonomy and Robust Architecture for Long-Duration Missions (Year 1: 1 July 2013 - 31 July 2014)

DTIC Science & Technology

2014-09-30

Mental Domain = Ω Goal Management goal change goal input World =Ψ Memory Mission & Goals( ) World Model (-Ψ) Episodic Memory Semantic Memory ...Activations Trace Meta-Level Control Introspective Monitoring Memory Reasoning Trace ( ) Strategies Episodic Memory Metaknowledge Self Model...it is from incorrect or missing memory associations (i.e., indices). Similarly, correct information may exist in the input stream, but may not be

Unified pre- and postsynaptic long-term plasticity enables reliable and flexible learning.

PubMed

Costa, Rui Ponte; Froemke, Robert C; Sjöström, P Jesper; van Rossum, Mark Cw

2015-08-26

Although it is well known that long-term synaptic plasticity can be expressed both pre- and postsynaptically, the functional consequences of this arrangement have remained elusive. We show that spike-timing-dependent plasticity with both pre- and postsynaptic expression develops receptive fields with reduced variability and improved discriminability compared to postsynaptic plasticity alone. These long-term modifications in receptive field statistics match recent sensory perception experiments. Moreover, learning with this form of plasticity leaves a hidden postsynaptic memory trace that enables fast relearning of previously stored information, providing a cellular substrate for memory savings. Our results reveal essential roles for presynaptic plasticity that are missed when only postsynaptic expression of long-term plasticity is considered, and suggest an experience-dependent distribution of pre- and postsynaptic strength changes.

Decay of Iconic Memory Traces Is Related to Psychometric Intelligence: A Fixed-Links Modeling Approach

ERIC Educational Resources Information Center

Miller, Robert; Rammsayer, Thomas H.; Schweizer, Karl; Troche, Stefan J.

2010-01-01

Several memory processes have been examined regarding their relation to psychometric intelligence with the exception of sensory memory. This study examined the relation between decay of iconic memory traces, measured with a partial-report task, and psychometric intelligence, assessed with the Berlin Intelligence Structure test, in 111…

NMDA-receptor blockade by CPP impairs post-training consolidation of a rapidly acquired spatial representation in rat hippocampus.

PubMed

McDonald, Robert J; Hong, Nancy S; Craig, Laura A; Holahan, Matthew R; Louis, Meira; Muller, Robert U

2005-09-01

Recent evidence suggests that N-methyl-D-aspartate (NMDA)-receptor mediated plasticity in hippocampus has a more subtle role in memory-based behaviours than originally thought. One idea is that NMDA-based plasticity is essential for the consolidation of post-training memory but not for the initial encoding or for short-term memory. To further test this idea we used a three-phase variant of the hidden goal water maze task. In the first phase, rats were pre-trained to an initial location. Next, intense, massed training was done in a 2-h interval to teach the rats to go to a new location after either an injection of the NMDA receptor antagonist (6)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) or of vehicle. Finally, under drug-free conditions 24 h after new location training, a competition test was done between the original and new locations. We find that N-methyl-D-aspartate (NMDA)-receptor blockade has little or no effect on new location training. In contrast, when tested 24 h later, the strength of the trace for the new location learned during NMDA-receptor blockade was much weaker compared with the trace for the new location learned after saline injection. Further experiments showed similar effects when NMDA-receptors were blocked immediately after the new location training, suggesting that this is a memory consolidation effect. Our results therefore reinforce the notion that hippocampal NMDA-receptors participate in post-training memory consolidation but are not essential for the processes necessary to learn or retain navigational information in the short term.

Sleep on your memory traces: How sleep effects can be explained by Act-In, a functional memory model.

PubMed

Cherdieu, Mélaine; Versace, Rémy; Rey, Amandine E; Vallet, Guillaume T; Mazza, Stéphanie

2018-06-01

Numerous studies have explored the effect of sleep on memory. It is well known that a period of sleep, compared to a similar period of wakefulness, protects memories from interference, improves performance, and might also reorganize memory traces in a way that encourages creativity and rule extraction. It is assumed that these benefits come from the reactivation of brain networks, mainly involving the hippocampal structure, as well as from their synchronization with neocortical networks during sleep, thereby underpinning sleep-dependent memory consolidation and reorganization. However, this memory reorganization is difficult to explain within classical memory models. The present paper aims to describe whether the influence of sleep on memory could be explained using a multiple trace memory model that is consistent with the concept of embodied cognition: the Act-In (activation-integration) memory model. We propose an original approach to the results observed in sleep research on the basis of two simple mechanisms, namely activation and integration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acute Ethanol Withdrawal Impairs Contextual Learning and Enhances Cued Learning

PubMed Central

Tipps, Megan E.; Raybuck, Jonathan D.; Buck, Kari J.; Lattal, K. Matthew

2014-01-01

Background Alcohol affects many of the brain regions and neural processes that support learning and memory, and these effects are thought to underlie, at least in part, the development of addiction. Although much work has been done regarding the effects of alcohol intoxication on learning and memory, little is known about the effects of acute withdrawal from a single alcohol exposure. Methods We assess the effects of acute ethanol withdrawal (6 h post-injection with 4 g/kg ethanol) on two forms of fear conditioning (delay and trace fear conditioning) in C57BL/6J and DBA/2J mice. The influence of a number of experimental parameters (pre- and post-training withdrawal exposure; foreground/background processing; training strength; non-associative effects) is also investigated. Results Acute ethanol withdrawal during training had a bidirectional effect on fear conditioned responses, decreasing contextual responses and increasing cued responses. These effects were apparent for both trace and delay conditioning in DBA/2J mice and for trace conditioning in C57BL/6J mice; however, C57BL/6J mice were selectively resistant to the effects of acute withdrawal on delay cued responses. Conclusions Our results show that acute withdrawal from a single, initial ethanol exposure is sufficient to alter long-term learning in mice. In addition, the differences between the strains and conditioning paradigms used suggest that specific learning processes can be differentially affected by acute withdrawal in a manner that is distinct from the reported effects of both alcohol intoxication and withdrawal following chronic alcohol exposure. Thus, our results suggest a unique effect of acute alcohol withdrawal on learning and memory processes. PMID:25684050

The Sensory Nature of Episodic Memory: Sensory Priming Effects Due to Memory Trace Activation

ERIC Educational Resources Information Center

Brunel, Lionel; Labeye, Elodie; Lesourd, Mathieu; Versace, Remy

2009-01-01

The aim of this study was to provide evidence that memory and perceptual processing are underpinned by the same mechanisms. Specifically, the authors conducted 3 experiments that emphasized the sensory aspect of memory traces. They examined their predictions with a short-term priming paradigm based on 2 distinct phases: a learning phase consisting…

Memory and consciousness: trace distinctiveness in memory retrievals.

PubMed

Brunel, Lionel; Oker, Ali; Riou, Benoit; Versace, Rémy

2010-12-01

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. Copyright © 2010 Elsevier Inc. All rights reserved.

Retrieval Search and Strength Evoke Dissociable Brain Activity during Episodic Memory Recall

PubMed Central

Reas, Emilie T.; Brewer, James B.

2014-01-01

Neuroimaging studies of episodic memory retrieval have revealed activations in the human frontal, parietal, and medial-temporal lobes that are associated with memory strength. However, it remains unclear whether these brain responses are veritable signals of memory strength or are instead regulated by concomitant subcomponents of retrieval such as retrieval effort or mental search. This study used event-related fMRI during cued recall of previously memorized word-pair associates to dissociate brain responses modulated by memory search from those modulated by the strength of a recalled memory. Search-related deactivations, dissociated from activity due to memory strength, were observed in regions of the default network, whereas distinctly strength-dependent activations were present in superior and inferior parietal and dorsolateral PFC. Both search and strength regulated activity in dorsal anterior cingulate and anterior insula. These findings suggest that, although highly correlated and partially subserved by overlapping cognitive control mechanisms, search and memory strength engage dissociable regions of frontoparietal attention and default networks. PMID:23190328

Fuzzy-trace theory: dual processes in memory, reasoning, and cognitive neuroscience.

PubMed

Brainerd, C J; Reyna, V F

2001-01-01

Fuzzy-trace theory has evolved in response to counterintuitive data on how memory development influences the development of reasoning. The two traditional perspectives on memory-reasoning relations--the necessity and constructivist hypotheses--stipulate that the accuracy of children's memory for problem information and the accuracy of their reasoning are closely intertwined, albeit for different reasons. However, contrary to necessity, correlational and experimental dissociations have been found between children's memory for problem information that is determinative in solving certain problems and their solutions of those problems. In these same tasks, age changes in memory for problem information appear to be dissociated from age changes in reasoning. Contrary to constructivism, correlational and experimental dissociations also have been found between children's performance on memory tests for actual experience and memory tests for the meaning of experience. As in memory-reasoning studies, age changes in one type of memory performance do not seem to be closely connected to age changes in the other type of performance. Subsequent experiments have led to dual-process accounts in both the memory and reasoning spheres. The account of memory development features four other principles: parallel verbatim-gist storage, dissociated verbatim-gist retrieval, memorial bases of conscious recollection, and identity/similarity processes. The account of the development of reasoning features three principles: gist extraction, fuzzy-to-verbatim continua, and fuzzy-processing preferences. The fuzzy-processing preference is a particularly important notion because it implies that gist-based intuitive reasoning often suffices to deliver "logical" solutions and that such reasoning confers multiple cognitive advantages that enhance accuracy. The explanation of memory-reasoning dissociations in cognitive development then falls out of fuzzy-trace theory's dual-process models of memory and reasoning. More explicitly, in childhood reasoning tasks, it is assumed that both verbatim and gist traces of problem information are stored. Responding accurately to memory tests for presented problem information depends primarily on verbatim memory abilities (preserving traces of that information and accessing them when the appropriate memory probes are administered). However, accurate solutions to reasoning problems depend primarily on gist-memory abilities (extracting the correct gist from problem information, focusing on that gist during reasoning, and accessing reasoning operations that process that gist). Because verbatim and gist memories exhibit considerable dissociation, both during storage and when they are subsequently accessed on memory tests, dissociations of verbatim-based memory performance from gist-based reasoning are predictable. Conversely, associations are predicted in situations in which memory and reasoning are based on the same verbatim traces (Brainerd & Reyna, 1988) and in situations in which memory and reasoning are based on the same gist traces (Reyna & Kiernan, 1994). Fuzzy-trace theory's memory and reasoning principles have been applied in other research domains. Four such domains are developmental cognitive neuroscience studies of false memory, studies of false memory in brain-damaged patients, studies of reasoning errors in judgment and decision making, and studies of retrieval mechanisms in recall. In the first domain, the principles of parallel verbatim-gist storage, dissociated verbatim-gist retrieval, and identity/similarity processes have been used to explain both spontaneous and implanted false reports in children and in the elderly. These explanations have produced some surprising predictions that have been verified: false reports do not merely decline with age during childhood but increase under theoretically specified conditions; reports of events that were not experienced can nevertheless be highly persistent over time; and false reports can be suppressed by retrieving verbatim traces of corresponding true events. In the second domain, the same principles have been invoked to explain why some forms of brain damage lead to elevated levels of false memory and other forms lead to reduced levels of false memory. In the third domain, the principles of gist extraction, fuzzy-to-verbatim continua, and fuzzy-processing preferences have been exploited to formulate a general theory of loci of processing failures in judgment and decision making, cluminating in a developmental account of degrees of rationality that distinguishes more and less advanced reasoning. This theory has in turn been used to formulate local models, such as the inclusion illusions model, that explain the characteristic reasoning errors that are observed on specific judgment and decision-making tasks. Finally, in the fourth domain, a dual-process conception of recall has been derived from the principles of parallel verbatim-gist storage and dissociated verbatim-gist retrieval. In this conception, which has been used to explain cognitive triage effects in recall and robust false recall, targets are recalled either by directly accessing their verbatim traces and reading the retrieved information out of consciousness or by reconstructively processing their gist traces.

The Molecular Basis of Memory

PubMed Central

2012-01-01

We propose a tripartite biochemical mechanism for memory. Three physiologic components are involved, namely, the neuron (individual and circuit), the surrounding neural extracellular matrix, and the various trace metals distributed within the matrix. The binding of a metal cation affects a corresponding nanostructure (shrinking, twisting, expansion) and dielectric sensibility of the chelating node (address) within the matrix lattice, sensed by the neuron. The neural extracellular matrix serves as an electro-elastic lattice, wherein neurons manipulate multiple trace metals (n > 10) to encode, store, and decode coginive information. The proposed mechanism explains brains low energy requirements and high rates of storage capacity described in multiples of Avogadro number (NA = 6 × 1023). Supportive evidence correlates memory loss to trace metal toxicity or deficiency, or breakdown in the delivery/transport of metals to the matrix, or its degradation. Inherited diseases revolving around dysfunctional trace metal metabolism and memory dysfunction, include Alzheimer's disease (Al, Zn, Fe), Wilson’s disease (Cu), thalassemia (Fe), and autism (metallothionein). The tripartite mechanism points to the electro-elastic interactions of neurons with trace metals distributed within the neural extracellular matrix, as the molecular underpinning of “synaptic plasticity” affecting short-term memory, long-term memory, and forgetting. PMID:23050060

Repetition Strengthens Target Recognition but Impairs Similar Lure Discrimination: Evidence for Trace Competition

ERIC Educational Resources Information Center

Reagh, Zachariah M.; Yassa, Michael A.

2014-01-01

Most theories of memory assume that representations are strengthened with repetition. We recently proposed Competitive Trace Theory, building on the hippocampus' powerful capacity to orthogonalize inputs into distinct outputs. We hypothesized that repetition elicits a similar but nonidentical memory trace, and that contextual details of…

Neural Global Pattern Similarity Underlies True and False Memories.

PubMed

Ye, Zhifang; Zhu, Bi; Zhuang, Liping; Lu, Zhonglin; Chen, Chuansheng; Xue, Gui

2016-06-22

The neural processes giving rise to human memory strength signals remain poorly understood. Inspired by formal computational models that posit a central role of global matching in memory strength, we tested a novel hypothesis that the strengths of both true and false memories arise from the global similarity of an item's neural activation pattern during retrieval to that of all the studied items during encoding (i.e., the encoding-retrieval neural global pattern similarity [ER-nGPS]). We revealed multiple ER-nGPS signals that carried distinct information and contributed differentially to true and false memories: Whereas the ER-nGPS in the parietal regions reflected semantic similarity and was scaled with the recognition strengths of both true and false memories, ER-nGPS in the visual cortex contributed solely to true memory. Moreover, ER-nGPS differences between the parietal and visual cortices were correlated with frontal monitoring processes. By combining computational and neuroimaging approaches, our results advance a mechanistic understanding of memory strength in recognition. What neural processes give rise to memory strength signals, and lead to our conscious feelings of familiarity? Using fMRI, we found that the memory strength of a given item depends not only on how it was encoded during learning, but also on the similarity of its neural representation with other studied items. The global neural matching signal, mainly in the parietal lobule, could account for the memory strengths of both studied and unstudied items. Interestingly, a different global matching signal, originated from the visual cortex, could distinguish true from false memories. The findings reveal multiple neural mechanisms underlying the memory strengths of events registered in the brain. Copyright © 2016 the authors 0270-6474/16/366792-11$15.00/0.

Muscarinic receptors in amygdala control trace fear conditioning.

PubMed

Baysinger, Amber N; Kent, Brianne A; Brown, Thomas H

2012-01-01

Intelligent behavior requires transient memory, which entails the ability to retain information over short time periods. A newly-emerging hypothesis posits that endogenous persistent firing (EPF) is the neurophysiological foundation for aspects or types of transient memory. EPF is enabled by the activation of muscarinic acetylcholine receptors (mAChRs) and is triggered by suprathreshold stimulation. EPF occurs in several brain regions, including the lateral amygdala (LA). The present study examined the role of amygdalar mAChRs in trace fear conditioning, a paradigm that requires transient memory. If mAChR-dependent EPF selectively supports transient memory, then blocking amygdalar mAChRs should impair trace conditioning, while sparing delay and context conditioning, which presumably do not rely upon transient memory. To test the EPF hypothesis, LA was bilaterally infused, prior to trace or delay conditioning, with either a mAChR antagonist (scopolamine) or saline. Computerized video analysis quantified the amount of freezing elicited by the cue and by the training context. Scopolamine infusion profoundly reduced freezing in the trace conditioning group but had no significant effect on delay or context conditioning. This pattern of results was uniquely anticipated by the EPF hypothesis. The present findings are discussed in terms of a systems-level theory of how EPF in LA and several other brain regions might help support trace fear conditioning.

The Distinctions of False and Fuzzy Memories.

ERIC Educational Resources Information Center

Schooler, Jonathan W.

1998-01-01

Notes that fuzzy-trace theory has been used to understand false memories of children. Demonstrates the irony imbedded in the theory, maintaining that a central implication of fuzzy-trace theory is that some errors characterized as false memories are not really false at all. These errors, when applied to false alarms to related lures, are best…

Decay uncovered in nonverbal short-term memory.

PubMed

Mercer, Tom; McKeown, Denis

2014-02-01

Decay theory posits that memory traces gradually fade away over the passage of time unless they are actively rehearsed. Much recent work exploring verbal short-term memory has challenged this theory, but there does appear to be evidence for trace decay in nonverbal auditory short-term memory. Numerous discrimination studies have reported a performance decline as the interval separating two tones is increased, consistent with a decay process. However, most of this tone comparison research can be explained in other ways, without reference to decay, and these alternative accounts were tested in the present study. In Experiment 1, signals were employed toward the end of extended retention intervals to ensure that listeners were alert to the presence and frequency content of the memoranda. In Experiment 2, a mask stimulus was employed in an attempt to distinguish between a highly detailed sensory trace and a longer-lasting short-term memory, and the distinctiveness of the stimuli was varied. Despite these precautions, slow-acting trace decay was observed. It therefore appears that the mere passage of time can lead to forgetting in some forms of short-term memory.

Global Neural Pattern Similarity as a Common Basis for Categorization and Recognition Memory

PubMed Central

Xue, Gui; Love, Bradley C.; Preston, Alison R.; Poldrack, Russell A.

2014-01-01

Familiarity, or memory strength, is a central construct in models of cognition. In previous categorization and long-term memory research, correlations have been found between psychological measures of memory strength and activation in the medial temporal lobes (MTLs), which suggests a common neural locus for memory strength. However, activation alone is insufficient for determining whether the same mechanisms underlie neural function across domains. Guided by mathematical models of categorization and long-term memory, we develop a theory and a method to test whether memory strength arises from the global similarity among neural representations. In human subjects, we find significant correlations between global similarity among activation patterns in the MTLs and both subsequent memory confidence in a recognition memory task and model-based measures of memory strength in a category learning task. Our work bridges formal cognitive theories and neuroscientific models by illustrating that the same global similarity computations underlie processing in multiple cognitive domains. Moreover, by establishing a link between neural similarity and psychological memory strength, our findings suggest that there may be an isomorphism between psychological and neural representational spaces that can be exploited to test cognitive theories at both the neural and behavioral levels. PMID:24872552

Genetic Dissociation of Acquisition and Memory Strength in the Heat-Box Spatial Learning Paradigm in "Drosophila"

ERIC Educational Resources Information Center

Diegelmann, Soeren; Zars, Melissa; Zars, Troy

2006-01-01

Memories can have different strengths, largely dependent on the intensity of reinforcers encountered. The relationship between reinforcement and memory strength is evident in asymptotic memory curves, with the level of the asymptote related to the intensity of the reinforcer. Although this is likely a fundamental property of memory formation,…

Visual Information-Processing in the Perception of Features and Objects

DTIC Science & Technology

1989-01-05

or nodes in a semantic memory network, whereas recall and recognition depend on separate episodic memory traces. In our experiment, we used the same...problem for the account in terms of the separation of episodic from semantic memory , since no pre- existing representations of our line patterns were... semantic memory : amnesic patients were thought to have lost the ability to lay down (or retrieve) episodic traces of autobiographical events, but had

Visuomotor learning in cerebellar patients.

PubMed

Timmann, D; Shimansky, Y; Larson, P S; Wunderlich, D A; Stelmach, G E; Bloedel, J R

1996-11-01

The aim of the present study was to demonstrate that patients with pathology affecting substantial regions of the cerebellum can improve their performance in a series of two-dimensional tracing tasks, thus supporting the view that this type of motor behavior can be acquired even when the integrity of this structure is compromised. Eight patients with chronic, isolated cerebellar lesions and eight age- and sex-matched healthy controls were tested. Three patients had mild, five had moderate upper limb ataxia. The experiment was divided into two parts. In the first, subjects traced an irregularly shaped outline over 20 consecutive trials ('Trace 1' task). Next, subjects were asked to redraw the object without any underlying template as a guide ('Memory 1' task). In the second part of the study, subjects were asked to trace a different, irregularly shaped outline over 20 consecutive trials ('Trace 2' task). Next, they were required to redraw it by memory with its axis rotated 90 degrees ('Memory 2' task). In each of the memory tasks the template was placed over the drawn image after each trial and shown to the subjects. The error of performance was determined by calculating three different measurements, each focused on different aspects of the task. Based on these measurements, the cerebellar patients showed improvement in both memory tasks. In the 'Memory 1' task the calculated error decreased significantly for the patients with mild ataxia. In the 'Memory 2' task all cerebellar patients improved their performance substantially enough to reduce significantly the magnitude of all three error measurements. The experiments demonstrate that patients with cerebellar lesions are capable of improving substantially their performance of a complex motor task involving the recall of memorized shapes and the visuomotor control of a tracing movement.

From learning to forgetting: behavioral, circuitry, and molecular properties define the different functional states of the recognition memory trace.

PubMed

Romero-Granados, Rocío; Fontán-Lozano, Angela; Delgado-García, José María; Carrión, Angel M

2010-05-01

Neuropsychological analyses of amnesic patients, as well as lesion experiments, indicate that the temporal lobe is essential for the encoding, storage, and expression of object recognition memory (ORM). However, temporal lobe structures directly involved in the consolidation and reconsolidation of these memories are not yet well-defined. We report here that systemic administration of a protein synthesis inhibitor before or up to 4 h after training or reactivation sessions impairs consolidation and reconsolidation of ORM, without affecting short-term memory. We have also observed that ORM reconsolidation is sensitive to protein synthesis inhibition, independently of the ORM trace age. Using bdnf and egr-1 gene expression analysis, we defined temporal lobe areas related to consolidation and reconsolidation of ORM. Training and reactivation 21 days after ORM acquisition sessions provoked changes in bdnf mRNA in somatosensory, perirhinal, and hippocampal cortices. Reactivation 2 days after the training session elicited changes in bdnf and egr-1 mRNA in entorhinal and prefrontal cortices, while reactivation 9 days post-training provoked an increase in egr-1 transcription in somatosensory and entorhinal cortices. The differences in activated circuits and in the capacity to recall the memory trace after 9 or 21 days post-training suggest that memory trace suffers functional changes in this period of time. All these results indicate that the functional state of the recognition memory trace, from acquisition to forgetting, can be specifically defined by behavioral, circuitry, and molecular properties. 2009 Wiley-Liss, Inc.

Grip Strength Is Associated With Cognitive Performance in Schizophrenia and the General Population: A UK Biobank Study of 476559 Participants.

PubMed

Firth, Joseph; Stubbs, Brendon; Vancampfort, Davy; Firth, Josh A; Large, Matthew; Rosenbaum, Simon; Hallgren, Mats; Ward, Philip B; Sarris, Jerome; Yung, Alison R

2018-06-06

Handgrip strength may provide an easily-administered marker of cognitive functional status. However, further population-scale research examining relationships between grip strength and cognitive performance across multiple domains is needed. Additionally, relationships between grip strength and cognitive functioning in people with schizophrenia, who frequently experience cognitive deficits, has yet to be explored. Baseline data from the UK Biobank (2007-2010) was analyzed; including 475397 individuals from the general population, and 1162 individuals with schizophrenia. Linear mixed models and generalized linear mixed models were used to assess the relationship between grip strength and 5 cognitive domains (visual memory, reaction time, reasoning, prospective memory, and number memory), controlling for age, gender, bodyweight, education, and geographical region. In the general population, maximal grip strength was positively and significantly related to visual memory (coefficient [coeff] = -0.1601, standard error [SE] = 0.003), reaction time (coeff = -0.0346, SE = 0.0004), reasoning (coeff = 0.2304, SE = 0.0079), number memory (coeff = 0.1616, SE = 0.0092), and prospective memory (coeff = 0.3486, SE = 0.0092: all P < .001). In the schizophrenia sample, grip strength was strongly related to visual memory (coeff = -0.155, SE = 0.042, P < .001) and reaction time (coeff = -0.049, SE = 0.009, P < .001), while prospective memory approached statistical significance (coeff = 0.233, SE = 0.132, P = .078), and no statistically significant association was found with number memory and reasoning (P > .1). Grip strength is significantly associated with cognitive functioning in the general population and individuals with schizophrenia, particularly for working memory and processing speed. Future research should establish directionality, examine if grip strength also predicts functional and physical health outcomes in schizophrenia, and determine whether interventions which improve muscular strength impact on cognitive and real-world functioning.

Ventral Fronto-Temporal Pathway Supporting Cognitive Control of Episodic Memory Retrieval

PubMed Central

Barredo, Jennifer; Öztekin, Ilke; Badre, David

2015-01-01

Achieving our goals often requires guiding access to relevant information from memory. Such goal-directed retrieval requires interactions between systems supporting cognitive control, including ventrolateral prefrontal cortex (VLPFC), and those supporting declarative memory, such as the medial temporal lobes (MTL). However, the pathways by which VLPFC interacts with MTL during retrieval are underspecified. Prior neuroanatomical evidence suggests that a polysynaptic ventral fronto-temporal pathway may support VLPFC–MTL interactions. To test this hypothesis, human participants were scanned using fMRI during performance of a source-monitoring task. The strength of source information was varied via repetition during encoding. Single encoding events should produce a weaker memory trace, thus recovering source information about these items should demand greater cognitive control. Results demonstrated that cortical targets along the ventral path—anterior VLPFC, temporal pole, anterior parahippocampus, and hippocampus—exhibited increases in univariate BOLD response correlated with increases in controlled retrieval demand, independent of factors related to response selection. Further, a functional connectivity analysis indicated that these regions functionally couple and are distinguishable from a dorsal pathway related to response selection demands. These data support a ventral retrieval pathway linking PFC and MTL. PMID:24177990

On the dynamic nature of the engram: evidence for circuit-level reorganization of object memory traces following reactivation.

PubMed

Winters, Boyer D; Tucci, Mark C; Jacklin, Derek L; Reid, James M; Newsome, James

2011-11-30

Research has implicated the perirhinal cortex (PRh) in several aspects of object recognition memory. The specific role of the hippocampus (HPC) remains controversial, but its involvement in object recognition may pertain to processing contextual information in relation to objects rather than object representation per se. Here we investigated the roles of the PRh and HPC in object memory reconsolidation using the spontaneous object recognition task for rats. Intra-PRh infusions of the protein synthesis inhibitor anisomycin immediately following memory reactivation prevented object memory reconsolidation. Similar deficits were observed when a novel object or a salient contextual change was introduced during the reactivation phase. Intra-HPC infusions of anisomycin, however, blocked object memory reconsolidation only when a contextual change was introduced during reactivation. Moreover, disrupting functional interaction between the HPC and PRh by infusing anisomycin unilaterally into each structure in opposite hemispheres also impaired reconsolidation when reactivation was done in an altered context. These results show for the first time that the PRh is critical for reconsolidation of object memory traces and provide insight into the dynamic process of object memory storage; the selective requirement for hippocampal involvement following reactivation in an altered context suggests a substantial circuit level object trace reorganization whereby an initially PRh-dependent object memory becomes reliant on both the HPC and PRh and their interaction. Such trace reorganization may play a central role in reconsolidation-mediated memory updating and could represent an important aspect of lingering consolidation processes proposed to underlie long-term memory modulation and stabilization.

False Memory for Orthographically versus Semantically Similar Words in Adolescents with Dyslexia: A Fuzzy-Trace Theory Perspective

ERIC Educational Resources Information Center

Obidzinski, Michal; Nieznanski, Marek

2017-01-01

The presented research was conducted in order to investigate the connections between developmental dyslexia and the functioning of verbatim and gist memory traces--assumed in the fuzzy-trace theory. The participants were 71 high school students (33 with dyslexia and 38 without learning difficulties). The modified procedure and multinomial model of…

Extinction training during the reconsolidation window prevents recovery of fear.

PubMed

Schiller, Daniela; Raio, Candace M; Phelps, Elizabeth A

2012-08-24

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents the return of fear. Pavlovian fear-conditioning paradigms are commonly employed to create a controlled, novel fear association in the laboratory. After pairing an innocuous stimulus (conditioned stimulus, CS) with an aversive outcome (unconditioned stimulus, US) we can elicit a fear response (conditioned response, or CR) by presenting just the stimulus alone. Once fear is acquired, it can be diminished using extinction training, whereby the conditioned stimulus is repeatedly presented without the aversive outcome until fear is no longer expressed. This inhibitory learning creates a new, safe representation for the CS, which competes for expression with the original fear memory. Although extinction is effective at inhibiting fear, it is not permanent. Fear can spontaneously recover with the passage of time. Exposure to stress or returning to the context of initial learning can also cause fear to resurface. Our protocol addresses the transient nature of extinction by targeting the reconsolidation window to modify emotional memory in a more permanent manner. Ample evidence suggests that reactivating a consolidated memory returns it to a labile state, during which the memory is again susceptible to interference. This window of opportunity appears to open shortly after reactivation and close approximately 6 hrs later, although this may vary depending on the strength and age of the memory. By allowing new information to incorporate into the original memory trace, this memory may be updated as it reconsolidates. Studies involving non-human animals have successfully blocked the expression of fear memory by introducing pharmacological manipulations within the reconsolidation window, however, most agents used are either toxic to humans or show equivocal effects when used in human studies. Our protocol addresses these challenges by offering an effective, yet non-invasive, behavioral manipulation that is safe for humans. By prompting fear memory retrieval prior to extinction, we essentially trigger the reconsolidation process, allowing new safety information (i.e., extinction) to be incorporated while the fear memory is still susceptible to interference. A recent study employing this behavioral manipulation in rats has successfully blocked fear memory using these temporal parameters. Additional studies in humans have demonstrated that introducing new information after the retrieval of previously consolidated motor, episodic, or declarative memories leads to interference with the original memory trace. We outline below a novel protocol used to block fear recovery in humans.

Global neural pattern similarity as a common basis for categorization and recognition memory.

PubMed

Davis, Tyler; Xue, Gui; Love, Bradley C; Preston, Alison R; Poldrack, Russell A

2014-05-28

Familiarity, or memory strength, is a central construct in models of cognition. In previous categorization and long-term memory research, correlations have been found between psychological measures of memory strength and activation in the medial temporal lobes (MTLs), which suggests a common neural locus for memory strength. However, activation alone is insufficient for determining whether the same mechanisms underlie neural function across domains. Guided by mathematical models of categorization and long-term memory, we develop a theory and a method to test whether memory strength arises from the global similarity among neural representations. In human subjects, we find significant correlations between global similarity among activation patterns in the MTLs and both subsequent memory confidence in a recognition memory task and model-based measures of memory strength in a category learning task. Our work bridges formal cognitive theories and neuroscientific models by illustrating that the same global similarity computations underlie processing in multiple cognitive domains. Moreover, by establishing a link between neural similarity and psychological memory strength, our findings suggest that there may be an isomorphism between psychological and neural representational spaces that can be exploited to test cognitive theories at both the neural and behavioral levels. Copyright © 2014 the authors 0270-6474/14/347472-13$15.00/0.

Research on Contextual Memorizing of Meaning in Foreign Language Vocabulary

ERIC Educational Resources Information Center

Xu, Linjing; Xiong, Qingxia; Qin, Yufang

2018-01-01

The purpose of this study was to examine the role of contexts in the memory of meaning in foreign vocabularies. The study was based on the cognitive processing hierarchy theory of Craik and Lockhart (1972), the memory trace theory of McClelland and Rumelhart (1986) and the memory trace theory of cognitive psychology. The subjects were non-English…

Arc expression identifies the lateral amygdala fear memory trace

PubMed Central

Gouty-Colomer, L A; Hosseini, B; Marcelo, I M; Schreiber, J; Slump, D E; Yamaguchi, S; Houweling, A R; Jaarsma, D; Elgersma, Y; Kushner, S A

2016-01-01

Memories are encoded within sparsely distributed neuronal ensembles. However, the defining cellular properties of neurons within a memory trace remain incompletely understood. Using a fluorescence-based Arc reporter, we were able to visually identify the distinct subset of lateral amygdala (LA) neurons activated during auditory fear conditioning. We found that Arc-expressing neurons have enhanced intrinsic excitability and are preferentially recruited into newly encoded memory traces. Furthermore, synaptic potentiation of thalamic inputs to the LA during fear conditioning is learning-specific, postsynaptically mediated and highly localized to Arc-expressing neurons. Taken together, our findings validate the immediate-early gene Arc as a molecular marker for the LA neuronal ensemble recruited during fear learning. Moreover, these results establish a model of fear memory formation in which intrinsic excitability determines neuronal selection, whereas learning-related encoding is governed by synaptic plasticity. PMID:25802982

Propranolol–induced Impairment of Contextual Fear Memory Reconsolidation in Rats: A similar Effect on Weak and Strong Recent and Remote Memories

PubMed Central

Taherian, Fatemeh; Vafaei, Abbas Ali; Vaezi, Gholam Hassan; Eskandarian, Sharaf; Kashef, Adel; Rashidy-Pour, Ali

2014-01-01

Introduction Previous studies have demonstrated that the β-adrenergic receptor antagonist propranolol impairs fear memory reconsolidation in experimental animals. There are experimental parameters such as the age and the strength of memory that can interact with pharmacological manipulations of memory reconsolidation. In this study, we investigated the ability of the age and the strength of memory to influence the disrupting effects of propranolol on fear memory reconsolidation in rats. Methods The rats were trained in a contextual fear conditioning using two (weak training) or five (strong training) footshocks (1mA). Propranolol (10mg/kg) injection was immediately followed retrieval of either a one-day recent (weak or strong) or 36-day remote (weak or strong) contextual fear memories. Results We found that propranolol induced a long-lasting impairment of subsequent expression of recent and remote memories with either weak or strong strength. We also found no memory recovery after a weak reminder shock. Furthermore, no significant differences were found on the amount of memory deficit induced by propranolol among memories with different age and strength. Discussion Our data suggest that the efficacy of propranolol in impairing fear memory reconsolidation is not limited to the age or strength of the memory. PMID:25337385

Interplay between Short- and Long-Term Plasticity in Cell-Assembly Formation

PubMed Central

Hiratani, Naoki; Fukai, Tomoki

2014-01-01

Various hippocampal and neocortical synapses of mammalian brain show both short-term plasticity and long-term plasticity, which are considered to underlie learning and memory by the brain. According to Hebb’s postulate, synaptic plasticity encodes memory traces of past experiences into cell assemblies in cortical circuits. However, it remains unclear how the various forms of long-term and short-term synaptic plasticity cooperatively create and reorganize such cell assemblies. Here, we investigate the mechanism in which the three forms of synaptic plasticity known in cortical circuits, i.e., spike-timing-dependent plasticity (STDP), short-term depression (STD) and homeostatic plasticity, cooperatively generate, retain and reorganize cell assemblies in a recurrent neuronal network model. We show that multiple cell assemblies generated by external stimuli can survive noisy spontaneous network activity for an adequate range of the strength of STD. Furthermore, our model predicts that a symmetric temporal window of STDP, such as observed in dopaminergic modulations on hippocampal neurons, is crucial for the retention and integration of multiple cell assemblies. These results may have implications for the understanding of cortical memory processes. PMID:25007209

Single-nitrogen-vacancy-center quantum memory for a superconducting flux qubit mediated by a ferromagnet

NASA Astrophysics Data System (ADS)

Lai, Yen-Yu; Lin, Guin-Dar; Twamley, Jason; Goan, Hsi-Sheng

2018-05-01

We propose a quantum memory scheme to transfer and store the quantum state of a superconducting flux qubit (FQ) into the electron spin of a single nitrogen-vacancy (NV) center in diamond via yttrium iron garnet (YIG), a ferromagnet. Unlike an ensemble of NV centers, the YIG moderator can enhance the effective FQ-NV-center coupling strength without introducing additional appreciable decoherence. We derive the effective interaction between the FQ and the NV center by tracing out the degrees of freedom of the collective mode of the YIG spins. We demonstrate the transfer, storage, and retrieval procedures, taking into account the effects of spontaneous decay and pure dephasing. Using realistic experimental parameters for the FQ, NV center and YIG, we find that a combined transfer, storage, and retrieval fidelity higher than 0.9, with a long storage time of 10 ms, can be achieved. This hybrid system not only acts as a promising quantum memory, but also provides an example of enhanced coupling between various systems through collective degrees of freedom.

A BDNF Sensitive Mechanism Is Involved in the Fear Memory Resulting from the Interaction between Stress and the Retrieval of an Established Trace

ERIC Educational Resources Information Center

Giachero, Marcelo; Bustos, Silvia G.; Calfa, Gaston; Molina, Victor A.

2013-01-01

The present study investigates the fear memory resulting from the interaction of a stressful experience and the retrieval of an established fear memory trace. Such a combination enhanced both fear expression and fear retention in adult Wistar rats. Likewise, midazolam intra-basolateral amygdala (BLA) infusion prior to stress attenuated the…

Elaboration versus suppression of cued memories: influence of memory recall instruction and success on parietal lobe, default network, and hippocampal activity.

PubMed

Gimbel, Sarah I; Brewer, James B

2014-01-01

Functional imaging studies of episodic memory retrieval consistently report task-evoked and memory-related activity in the medial temporal lobe, default network and parietal lobe subregions. Associated components of memory retrieval, such as attention-shifts, search, retrieval success, and post-retrieval processing also influence regional activity, but these influences remain ill-defined. To better understand how top-down control affects the neural bases of memory retrieval, we examined how regional activity responses were modulated by task goals during recall success or failure. Specifically, activity was examined during memory suppression, recall, and elaborative recall of paired-associates. Parietal lobe was subdivided into dorsal (BA 7), posterior ventral (BA 39), and anterior ventral (BA 40) regions, which were investigated separately to examine hypothesized distinctions in sub-regional functional responses related to differential attention-to-memory and memory strength. Top-down suppression of recall abolished memory strength effects in BA 39, which showed a task-negative response, and BA 40, which showed a task-positive response. The task-negative response in default network showed greater negatively-deflected signal for forgotten pairs when task goals required recall. Hippocampal activity was task-positive and was influenced by memory strength only when task goals required recall. As in previous studies, we show a memory strength effect in parietal lobe and hippocampus, but we show that this effect is top-down controlled and sensitive to whether the subject is trying to suppress or retrieve a memory. These regions are all implicated in memory recall, but their individual activity patterns show distinct memory-strength-related responses when task goals are varied. In parietal lobe, default network, and hippocampus, top-down control can override the commonly identified effects of memory strength.

Elaboration versus Suppression of Cued Memories: Influence of Memory Recall Instruction and Success on Parietal Lobe, Default Network, and Hippocampal Activity

PubMed Central

Gimbel, Sarah I.; Brewer, James B.

2014-01-01

Functional imaging studies of episodic memory retrieval consistently report task-evoked and memory-related activity in the medial temporal lobe, default network and parietal lobe subregions. Associated components of memory retrieval, such as attention-shifts, search, retrieval success, and post-retrieval processing also influence regional activity, but these influences remain ill-defined. To better understand how top-down control affects the neural bases of memory retrieval, we examined how regional activity responses were modulated by task goals during recall success or failure. Specifically, activity was examined during memory suppression, recall, and elaborative recall of paired-associates. Parietal lobe was subdivided into dorsal (BA 7), posterior ventral (BA 39), and anterior ventral (BA 40) regions, which were investigated separately to examine hypothesized distinctions in sub-regional functional responses related to differential attention-to-memory and memory strength. Top-down suppression of recall abolished memory strength effects in BA 39, which showed a task-negative response, and BA 40, which showed a task-positive response. The task-negative response in default network showed greater negatively-deflected signal for forgotten pairs when task goals required recall. Hippocampal activity was task-positive and was influenced by memory strength only when task goals required recall. As in previous studies, we show a memory strength effect in parietal lobe and hippocampus, but we show that this effect is top-down controlled and sensitive to whether the subject is trying to suppress or retrieve a memory. These regions are all implicated in memory recall, but their individual activity patterns show distinct memory-strength-related responses when task goals are varied. In parietal lobe, default network, and hippocampus, top-down control can override the commonly identified effects of memory strength. PMID:24586492

Sleep Shelters Verbal Memory from Different Kinds of Interference

PubMed Central

Sheth, Bhavin R.; Varghese, Reni; Truong, Thuy

2012-01-01

Study Objectives: Studies have shown that sleep shelters old verbal memories from associative interference arising from new, more recently acquired memories. Our objective is to extend the forms of interference for which sleep provides a sheltering benefit to non-associative and prospective interference, and to examine experimental conditions and memory strengths for which sleep before or after learning particularly affects verbal memory consolidation. Design: Acquiring paired word associates, retention across intervening sleep and wake, training on new, interfering word associates, and test recall of both sets. Setting: University laboratory. Participants: Healthy volunteers. Interventions: N/A. Measurements and Results: Comparing recall before and after intervening periods of sleep versus wake, we found that: (i) Sleep preferentially shields weakly encoded verbal memories from retroactive interference. (ii) Sleep immediately following learning helps shelter memory from associative and non-associative forms of retroactive interference. (iii) Sleep protects new verbal memories from prospective interference. (iv) Word associations acquired for the first time in the evening after a day spent in the wake state are encoded more strongly than word associations acquired in the morning following a night of sleep. Conclusions: The findings extend the known sleep protection from interference to non-associative as well as prospective interference, and limit the protection to weakly encoded word associations. Combined, our results suggest that sleep immediately after verbal learning isolates newly formed memory traces and renders them inaccessible, except by specific contextual cues. Memory isolation in sleep is a passive mechanism that can reasonably account for several experimental findings. Citation: Sheth BR; Varghese R; Truong T. Sleep shelters verbal memory from different kinds of interference. SLEEP 2012;35(7):985-996. PMID:22754045

Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence

PubMed Central

Gilbert, Annie C.; Boucher, Victor J.; Jemel, Boutheina

2014-01-01

We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis. PMID:24678304

Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence.

PubMed

Gilbert, Annie C; Boucher, Victor J; Jemel, Boutheina

2014-01-01

We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis.

Effect of acoustic similarity on short-term auditory memory in the monkey

PubMed Central

Scott, Brian H.; Mishkin, Mortimer; Yin, Pingbo

2013-01-01

Recent evidence suggests that the monkey’s short-term memory in audition depends on a passively retained sensory trace as opposed to a trace reactivated from long-term memory for use in working memory. Reliance on a passive sensory trace could render memory particularly susceptible to confusion between sounds that are similar in some acoustic dimension. If so, then in delayed matching-to-sample, the monkey’s performance should be predicted by the similarity in the salient acoustic dimension between the sample and subsequent test stimulus, even at very short delays. To test this prediction and isolate the acoustic features relevant to short-term memory, we examined the pattern of errors made by two rhesus monkeys performing a serial, auditory delayed match-to-sample task with interstimulus intervals of 1 s. The analysis revealed that false-alarm errors did indeed result from similarity-based confusion between the sample and the subsequent nonmatch stimuli. Manipulation of the stimuli showed that removal of spectral cues was more disruptive to matching behavior than removal of temporal cues. In addition, the effect of acoustic similarity on false-alarm response was stronger at the first nonmatch stimulus than at the second one. This pattern of errors would be expected if the first nonmatch stimulus overwrote the sample’s trace, and suggests that the passively retained trace is not only vulnerable to similarity-based confusion but is also highly susceptible to overwriting. PMID:23376550

Effect of acoustic similarity on short-term auditory memory in the monkey.

PubMed

Scott, Brian H; Mishkin, Mortimer; Yin, Pingbo

2013-04-01

Recent evidence suggests that the monkey's short-term memory in audition depends on a passively retained sensory trace as opposed to a trace reactivated from long-term memory for use in working memory. Reliance on a passive sensory trace could render memory particularly susceptible to confusion between sounds that are similar in some acoustic dimension. If so, then in delayed matching-to-sample, the monkey's performance should be predicted by the similarity in the salient acoustic dimension between the sample and subsequent test stimulus, even at very short delays. To test this prediction and isolate the acoustic features relevant to short-term memory, we examined the pattern of errors made by two rhesus monkeys performing a serial, auditory delayed match-to-sample task with interstimulus intervals of 1 s. The analysis revealed that false-alarm errors did indeed result from similarity-based confusion between the sample and the subsequent nonmatch stimuli. Manipulation of the stimuli showed that removal of spectral cues was more disruptive to matching behavior than removal of temporal cues. In addition, the effect of acoustic similarity on false-alarm response was stronger at the first nonmatch stimulus than at the second one. This pattern of errors would be expected if the first nonmatch stimulus overwrote the sample's trace, and suggests that the passively retained trace is not only vulnerable to similarity-based confusion but is also highly susceptible to overwriting. Copyright © 2013 Elsevier B.V. All rights reserved.

Consolidation and restoration of memory traces in working memory.

PubMed

De Schrijver, Sébastien; Barrouillet, Pierre

2017-10-01

Consolidation is the process through which ephemeral sensory traces are transformed into more stable short-term memory traces. It has been shown that consolidation plays a crucial role in working memory (WM) performance, by strengthening memory traces that then better resist interference and decay. In a recent study, Bayliss, Bogdanovs, and Jarrold (Journal of Memory and Language, 81, 34-50, 2015) argued that this process is separate from the processes known to restore WM traces after degradation, such as attentional refreshing and verbal rehearsal. In the present study, we investigated the relationship between the two types of processes in the context of WM span tasks. Participants were presented with series of letters for serial recall, each letter being followed by four digits for parity judgment. Consolidation opportunity was manipulated by varying the delay between each letter and the first digit to be processed, while opportunities for restoration were manipulated by varying the pace at which the parity task had to be performed (i.e., its cognitive load, or CL). Increasing the time available for either consolidation or restoration resulted in higher WM spans, with some substitutability between the two processes. Accordingly, when consolidation time was added to restoration time in the calculation of CL, the new resulting index, called extended CL, proved a very good predictor of recall performance, a finding also observed when verbal rehearsal was prevented by articulatory suppression. This substitutability between consolidation and restoration suggests that both processes may rely on the same mechanisms.

Postretrieval new learning does not reliably induce human memory updating via reconsolidation.

PubMed

Hardwicke, Tom E; Taqi, Mahdi; Shanks, David R

2016-05-10

Reconsolidation theory proposes that retrieval can destabilize an existing memory trace, opening a time-dependent window during which that trace is amenable to modification. Support for the theory is largely drawn from nonhuman animal studies that use invasive pharmacological or electroconvulsive interventions to disrupt a putative postretrieval restabilization ("reconsolidation") process. In human reconsolidation studies, however, it is often claimed that postretrieval new learning can be used as a means of "updating" or "rewriting" existing memory traces. This proposal warrants close scrutiny because the ability to modify information stored in the memory system has profound theoretical, clinical, and ethical implications. The present study aimed to replicate and extend a prominent 3-day motor-sequence learning study [Walker MP, Brakefield T, Hobson JA, Stickgold R (2003) Nature 425(6958):616-620] that is widely cited as a convincing demonstration of human reconsolidation. However, in four direct replication attempts (n = 64), we did not observe the critical impairment effect that has previously been taken to indicate disruption of an existing motor memory trace. In three additional conceptual replications (n = 48), we explored the broader validity of reconsolidation-updating theory by using a declarative recall task and sequences similar to phone numbers or computer passwords. Rather than inducing vulnerability to interference, memory retrieval appeared to aid the preservation of existing sequence knowledge relative to a no-retrieval control group. These findings suggest that memory retrieval followed by new learning does not reliably induce human memory updating via reconsolidation.

Neuronal Oscillations Indicate Sleep-dependent Changes in the Cortical Memory Trace.

PubMed

Köster, Moritz; Finger, Holger; Kater, Maren-Jo; Schenk, Christoph; Gruber, Thomas

2017-04-01

Sleep promotes the consolidation of newly acquired associative memories. Here we used neuronal oscillations in the human EEG to investigate sleep-dependent changes in the cortical memory trace. The retrieval activity for object-color associations was assessed immediately after encoding and after 3 hr of sleep or wakefulness. Sleep had beneficial effects on memory performance and led to reduced event-related theta and gamma power during the retrieval of associative memories. Furthermore, event-related alpha suppression was attenuated in the wake group for memorized and novel stimuli. There were no sleep-dependent changes in retrieval activity for missed items or items retrieved without color. Thus, the sleep-dependent reduction in theta and gamma oscillations was specific for the retrieval of associative memories. In line with theoretical accounts on sleep-dependent memory consolidation, decreased theta may indicate reduced mediotemporal activity because of a transfer of information into neocortical networks during sleep, whereas reduced parietal gamma may reflect effects of synaptic downscaling. Changes in alpha suppression in the wake group possibly index reduced attentional resources that may also contribute to a lower memory performance in this group. These findings indicate that the consolidation of associative memories during sleep is associated with profound changes in the cortical memory trace and relies on multiple neuronal processes working in concert.

Role of Immediate-Early Genes in Synaptic Plasticity and Neuronal Ensembles Underlying the Memory Trace

PubMed Central

Minatohara, Keiichiro; Akiyoshi, Mika; Okuno, Hiroyuki

2016-01-01

In the brain, neuronal gene expression is dynamically changed in response to neuronal activity. In particular, the expression of immediate-early genes (IEGs) such as egr-1, c-fos, and Arc is rapidly and selectively upregulated in subsets of neurons in specific brain regions associated with learning and memory formation. IEG expression has therefore been widely used as a molecular marker for neuronal populations that undergo plastic changes underlying formation of long-term memory. In recent years, optogenetic and pharmacogenetic studies of neurons expressing c-fos or Arc have revealed that, during learning, IEG-positive neurons encode and store information that is required for memory recall, suggesting that they may be involved in formation of the memory trace. However, despite accumulating evidence for the role of IEGs in synaptic plasticity, the molecular and cellular mechanisms associated with this process remain unclear. In this review, we first summarize recent literature concerning the role of IEG-expressing neuronal ensembles in organizing the memory trace. We then focus on the physiological significance of IEGs, especially Arc, in synaptic plasticity, and describe our hypotheses about the importance of Arc expression in various types of input-specific circuit reorganization. Finally, we offer perspectives on Arc function that would unveil the role of IEG-expressing neurons in the formation of memory traces in the hippocampus and other brain areas. PMID:26778955

Updating Procedures Can Reorganize the Neural Circuit Supporting a Fear Memory.

PubMed

Kwapis, Janine L; Jarome, Timothy J; Ferrara, Nicole C; Helmstetter, Fred J

2017-07-01

Established memories undergo a period of vulnerability following retrieval, a process termed 'reconsolidation.' Recent work has shown that the hypothetical process of reconsolidation is only triggered when new information is presented during retrieval, suggesting that this process may allow existing memories to be modified. Reconsolidation has received increasing attention as a possible therapeutic target for treating disorders that stem from traumatic memories, yet little is known about how this process changes the original memory. In particular, it is unknown whether reconsolidation can reorganize the neural circuit supporting an existing memory after that memory is modified with new information. Here, we show that trace fear memory undergoes a protein synthesis-dependent reconsolidation process following exposure to a single updating trial of delay conditioning. Further, this reconsolidation-dependent updating process appears to reorganize the neural circuit supporting the trace-trained memory, so that it better reflects the circuit supporting delay fear. Specifically, after a trace-to-delay update session, the amygdala is now required for extinction of the updated memory but the retrosplenial cortex is no longer required for retrieval. These results suggest that updating procedures could be used to force a complex, poorly defined memory circuit to rely on a better-defined neural circuit that may be more amenable to behavioral or pharmacological manipulation. This is the first evidence that exposure to new information can fundamentally reorganize the neural circuit supporting an existing memory.

Scalability Analysis of Gleipnir: A Memory Tracing and Profiling Tool, on Titan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janjusic, Tommy; Kartsaklis, Christos; Wang, Dali

2013-01-01

Application performance is hindered by a variety of factors but most notably driven by the well know CPU-memory speed gap (also known as the memory wall). Understanding application s memory behavior is key if we are trying to optimize performance. Understanding application performance properties is facilitated with various performance profiling tools. The scope of profiling tools varies in complexity, ease of deployment, profiling performance, and the detail of profiled information. Specifically, using profiling tools for performance analysis is a common task when optimizing and understanding scientific applications on complex and large scale systems such as Cray s XK7. This papermore » describes the performance characteristics of using Gleipnir, a memory tracing tool, on the Titan Cray XK7 system when instrumenting large applications such as the Community Earth System Model. Gleipnir is a memory tracing tool built as a plug-in tool for the Valgrind instrumentation framework. The goal of Gleipnir is to provide fine-grained trace information. The generated traces are a stream of executed memory transactions mapped to internal structures per process, thread, function, and finally the data structure or variable. Our focus was to expose tool performance characteristics when using Gleipnir with a combination of an external tools such as a cache simulator, Gl CSim, to characterize the tool s overall performance. In this paper we describe our experience with deploying Gleipnir on the Titan Cray XK7 system, report on the tool s ease-of-use, and analyze run-time performance characteristics under various workloads. While all performance aspects are important we mainly focus on I/O characteristics analysis due to the emphasis on the tools output which are trace-files. Moreover, the tool is dependent on the run-time system to provide the necessary infrastructure to expose low level system detail; therefore, we also discuss any theoretical benefits that can be achieved if such modules were present.« less

Remembered study mode: support for the distinctiveness account of the production effect.

PubMed

Ozubko, Jason D; Major, Jennifer; MacLeod, Colin M

2014-01-01

The production effect is the finding that words spoken aloud at study are subsequently remembered better than are words read silently at study. According to the distinctiveness account, aloud words are remembered better because the act of speaking those words aloud is encoded and later recovery of this information can be used to infer that those words were studied. An alternative account (the strength-based account) is that memory strength is simply greater for words read aloud. To discriminate these two accounts, we investigated study mode judgements (i.e., "aloud"/"silent"/"new" ratings): The strength-based account predicts that "aloud" responses should positively correlate with memory strength, whereas the distinctiveness account predicts that accuracy of study mode judgements will be independent of memory strength. Across three experiments, where the strength of some silent words was increased by repetition, study mode was discriminable regardless of strength-even when the strength of aloud and repeated silent items was equivalent. Consistent with the distinctiveness account, we conclude that memory for "aloudness" is independent of memory strength and a likely candidate to explain the production effect.

An engram found? Evaluating the evidence from fruit flies.

PubMed

Gerber, Bertram; Tanimoto, Hiromu; Heisenberg, Martin

2004-12-01

Is it possible to localize a memory trace to a subset of cells in the brain? If so, it should be possible to show: first, that neuronal plasticity occurs in these cells. Second, that neuronal plasticity in these cells is sufficient for memory. Third, that neuronal plasticity in these cells is necessary for memory. Fourth, that memory is abolished if these cells cannot provide output during testing. And fifth, that memory is abolished if these cells cannot receive input during training. With regard to olfactory learning in flies, we argue that the notion of the olfactory memory trace being localized to the Kenyon cells of the mushroom bodies is a reasonable working hypothesis.

An essential memory trace found.

PubMed

Thompson, Richard F

2013-10-01

I argue here that we have succeeded in localizing an essential memory trace for a basic form of associative learning and memory--classical conditioning of discrete responses learned with an aversive stimulus--to the anterior interpositus nucleus of the cerebellum. We first identified the entire essential circuit, using eyelid conditioning as the model system, and used reversible inactivation, during training, of critical structures and pathways to localize definitively the essential memory trace. In recognition of the 30th anniversary of Behavioral Neuroscience, I highlight 1 paper (Tracy, Thompson, Krupa, & Thompson, 1998) that was particularly significant for the progress of this research program. In this review, I present definitive evidence that the essential memory trace for eyelid conditioning is localized to the cerebellum and to no other part of the essential circuit, using electrical stimulation of the pontine nuclei-mossy fibers projecting to the cerebellum as the conditional stimulus (CS; it proved to be a supernormal stimulus resulting in much faster learning than with any peripheral CS) and using an electrical stimulus to the output of the cerebellum as a test, which did not change. Pontine patterns of projection to the cerebellum were confirmed with retrograde labeling techniques. 2013 APA, all rights reserved

Memory Skills of Deaf Learners: Implications and Applications

ERIC Educational Resources Information Center

Hamilton, Harley

2011-01-01

This paper will review research on working memory and short-term memory abilities of deaf individuals delineating strengths and weaknesses. The areas of memory reviewed include weaknesses such as sequential recall, processing speed, attention, and memory load. Strengths include free recall, visuospatial recall, imagery and dual encoding.…

Memory skills of deaf learners: implications and applications.

PubMed

Hamilton, Harley

2011-01-01

The author reviews research on working memory and short-term memory abilities of deaf individuals, delineating strengths and weaknesses. Among the areas of weakness that are reviewed are sequential recall, processing speed, attention, and memory load. Areas of strengths include free recall, visuospatial recall, imagery, and dual encoding. Phonological encoding and rehearsal appear to be strengths when these strategies are employed. The implications of the strengths and weaknesses for language learning and educational achievement are discussed. Research questions are posed, and remedial and compensatory classroom applications are suggested.

Affect influences feature binding in memory: Trading between richness and strength of memory representations.

PubMed

Spachtholz, Philipp; Kuhbandner, Christof; Pekrun, Reinhard

2016-10-01

Research has shown that long-term memory representations of objects are formed as a natural product of perception even without any intentional memorization. It is not known, however, how rich these representations are in terms of the number of bound object features. In particular, because feature binding rests on resource-limited processes, there may be a context-dependent trade-off between the quantity of stored features and their memory strength. The authors examined whether affective state may bring about such a trade-off. Participants incidentally encoded pictures of real-world objects while experiencing positive or negative affect, and the authors later measured memory for 2 features. Results showed that participants traded between richness and strength of memory representations as a function of affect, with positive affect tuning memory formation toward richness and negative affect tuning memory formation toward strength. These findings demonstrate that memory binding is a flexible process that is modulated by affective state. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Cognitive Processing in Oral and Silent Reading Comprehension.

ERIC Educational Resources Information Center

Salasoo, Aita

1986-01-01

Reading rates and comprehension measures that probed recognition of various levels of text structure were collected for passages read orally and silently by 16 college students. Results showed that memory traces of text microstructure created in oral reading were accessed faster during memory-based comprehension tasks than traces established by…

Recollection and familiarity in hippocampal amnesia.

PubMed

Turriziani, Patrizia; Serra, Laura; Fadda, Lucia; Caltagirone, Carlo; Carlesimo, Giovanni Augusto

2008-01-01

Currently, there is a general agreement that two distinct cognitive operations, recollection and familiarity, contribute to performance on recognition memory tests. However, there is a controversy about whether recollection and familiarity reflect different memory processes, mediated by distinct neural substrates (dual-process models), or whether they are the expression of memory traces of different strength in the context of a unitary declarative memory system (unitary-strength models). Critical in this debate is the status of recognition memory in hippocampal amnesia and, in particular, whether the various structures in the medial temporal lobe (MTL) contribute differentially to the recollection and familiarity components of recognition. The present study aimed to explore the relative contribution of recollection and familiarity to recognition of words that had been previously read or that had been previously generated in a group of severely amnesic patients with cerebral damage restricted to the hippocampus. A convergent pattern of results emerged when we used a subjective-based (remember/know; R/K) and an objective-based (process dissociation procedure; PDP) methods to estimate the contribution of recollection and familiarity to recognition performance. In both PDP and R/K procedures, healthy controls disclosed significantly higher recollection estimates for words that had been anagrammed than for words that had been read. Amnesic patients' recollection scores were not different for words that had been generated or that had been read, and the recollection estimate for words that had been generated was significantly reduced as compared to the group of healthy controls. For familiarity, both healthy controls and amnesic patients recognized as familiar more words that had been generated than words that had been read, and there was no difference between the two groups. These data support the hypothesis of a specific role of the hippocampus in recollection processes and suggest that other components of the MTL (e.g., perirhinal cortex) may be more involved in the process of familiarity. 2008 Wiley-Liss, Inc.

Emotion strengthens high priority memory traces but weakens low priority memory traces

PubMed Central

Sakaki, Michiko; Fryer, Kellie; Mather, Mara

2014-01-01

When encountering emotional events, memory for those events is typically enhanced. But it has been unclear how emotionally arousing events influence memory for preceding information. Does emotional arousal induce retrograde amnesia or retrograde enhancement? The current study revealed that this depends on the top-down goal relevance of the preceding information. Across three studies, we found that emotional arousal induced by one image facilitated memory for the preceding neutral item when people prioritized that neutral item. In contrast, an emotional image impaired memory for the preceding neutral item when people did not prioritize that neutral item. Emotional arousal elicited by negative and positive pictures both showed this pattern of enhancing or impairing memory for the preceding stimulus depending on its priority. These results indicate that emotional arousal amplifies the effects of top-down priority in memory formation. PMID:24311478

The computational nature of memory modification.

PubMed

Gershman, Samuel J; Monfils, Marie-H; Norman, Kenneth A; Niv, Yael

2017-03-15

Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature.

Memory dynamics under stress.

PubMed

Quaedflieg, Conny W E M; Schwabe, Lars

2018-03-01

Stressful events have a major impact on memory. They modulate memory formation in a time-dependent manner, closely linked to the temporal profile of action of major stress mediators, in particular catecholamines and glucocorticoids. Shortly after stressor onset, rapidly acting catecholamines and fast, non-genomic glucocorticoid actions direct cognitive resources to the processing and consolidation of the ongoing threat. In parallel, control of memory is biased towards rather rigid systems, promoting habitual forms of memory allowing efficient processing under stress, at the expense of "cognitive" systems supporting memory flexibility and specificity. In this review, we discuss the implications of this shift in the balance of multiple memory systems for the dynamics of the memory trace. Specifically, stress appears to hinder the incorporation of contextual details into the memory trace, to impede the integration of new information into existing knowledge structures, to impair the flexible generalisation across past experiences, and to hamper the modification of memories in light of new information. Delayed, genomic glucocorticoid actions might reverse the control of memory, thus restoring homeostasis and "cognitive" control of memory again.

A buffer model of memory encoding and temporal correlations in retrieval.

PubMed

Lehman, Melissa; Malmberg, Kenneth J

2013-01-01

Atkinson and Shiffrin's (1968) dual-store model of memory includes structural aspects of memory along with control processes. The rehearsal buffer is a process by which items are kept in mind and long-term episodic traces are formed. The model has been both influential and controversial. Here, we describe a novel variant of Atkinson and Shiffrin's buffer model within the framework of the retrieving effectively from memory theory (REM; Shiffrin & Steyvers, 1997) that accounts for findings previously thought to be difficult for such models to explain. This model assumes a limited-capacity buffer where information is stored about items, along with information about associations between items and between items and the context in which they are studied. The strength of association between items and context is limited by the number of items simultaneously occupying the buffer (Lehman & Malmberg, 2009). The contents of the buffer are managed by complementary processes of rehearsal and compartmentalization (Lehman & Malmberg, 2011). New findings that directly test a priori predictions of the model are reported, including serial position effects and conditional and first recall probabilities in immediate and delayed free recall, in a continuous distractor paradigm, and in experiments using list-length manipulations of single-item and paired-item study lists.

Synaptic Mechanisms of Memory Consolidation during Sleep Slow Oscillations

PubMed Central

Wei, Yina; Krishnan, Giri P.

2016-01-01

Sleep is critical for regulation of synaptic efficacy, memories, and learning. However, the underlying mechanisms of how sleep rhythms contribute to consolidating memories acquired during wakefulness remain unclear. Here we studied the role of slow oscillations, 0.2–1 Hz rhythmic transitions between Up and Down states during stage 3/4 sleep, on dynamics of synaptic connectivity in the thalamocortical network model implementing spike-timing-dependent synaptic plasticity. We found that the spatiotemporal pattern of Up-state propagation determines the changes of synaptic strengths between neurons. Furthermore, an external input, mimicking hippocampal ripples, delivered to the cortical network results in input-specific changes of synaptic weights, which persisted after stimulation was removed. These synaptic changes promoted replay of specific firing sequences of the cortical neurons. Our study proposes a neuronal mechanism on how an interaction between hippocampal input, such as mediated by sharp wave-ripple events, cortical slow oscillations, and synaptic plasticity, may lead to consolidation of memories through preferential replay of cortical cell spike sequences during slow-wave sleep. SIGNIFICANCE STATEMENT Sleep is critical for memory and learning. Replay during sleep of temporally ordered spike sequences related to a recent experience was proposed to be a neuronal substrate of memory consolidation. However, specific mechanisms of replay or how spike sequence replay leads to synaptic changes that underlie memory consolidation are still poorly understood. Here we used a detailed computational model of the thalamocortical system to report that interaction between slow cortical oscillations and synaptic plasticity during deep sleep can underlie mapping hippocampal memory traces to persistent cortical representation. This study provided, for the first time, a mechanistic explanation of how slow-wave sleep may promote consolidation of recent memory events. PMID:27076422

Network-wide reorganization of procedural memory during NREM sleep revealed by fMRI

PubMed Central

Vahdat, Shahabeddin; Fogel, Stuart; Benali, Habib; Doyon, Julien

2017-01-01

Sleep is necessary for the optimal consolidation of newly acquired procedural memories. However, the mechanisms by which motor memory traces develop during sleep remain controversial in humans, as this process has been mainly investigated indirectly by comparing pre- and post-sleep conditions. Here, we used functional magnetic resonance imaging and electroencephalography during sleep following motor sequence learning to investigate how newly-formed memory traces evolve dynamically over time. We provide direct evidence for transient reactivation followed by downscaling of functional connectivity in a cortically-dominant pattern formed during learning, as well as gradual reorganization of this representation toward a subcortically-dominant consolidated trace during non-rapid eye movement (NREM) sleep. Importantly, the putamen functional connectivity within the consolidated network during NREM sleep was related to overnight behavioral gains. Our results demonstrate that NREM sleep is necessary for two complementary processes: the restoration and reorganization of newly-learned information during sleep, which underlie human motor memory consolidation. DOI: http://dx.doi.org/10.7554/eLife.24987.001 PMID:28892464

Optogenetic stimulation of dentate gyrus engrams restores memory in Alzheimer's disease mice.

PubMed

Perusini, Jennifer N; Cajigas, Stephanie A; Cohensedgh, Omid; Lim, Sean C; Pavlova, Ina P; Donaldson, Zoe R; Denny, Christine A

2017-10-01

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by amyloid-beta (Aβ) plaques and tau neurofibrillary tangles. APPswe/PS1dE9 (APP/PS1) mice have been developed as an AD model and are characterized by plaque formation at 4-6 months of age. Here, we sought to better understand AD-related cognitive decline by characterizing various types of memory. In order to better understand how memory declines with AD, APP/PS1 mice were bred with ArcCreER T2 mice. In this line, neural ensembles activated during memory encoding can be indelibly tagged and directly compared with neural ensembles activated during memory retrieval (i.e., memory traces/engrams). We first administered a battery of tests examining depressive- and anxiety-like behaviors, as well as spatial, social, and cognitive memory to APP/PS1 × ArcCreER T2 × channelrhodopsin (ChR2)-enhanced yellow fluorescent protein (EYFP) mice. Dentate gyrus (DG) neural ensembles were then optogenetically stimulated in these mice to improve memory impairment. AD mice had the most extensive differences in fear memory, as assessed by contextual fear conditioning (CFC), which was accompanied by impaired DG memory traces. Optogenetic stimulation of DG neural ensembles representing a CFC memory increased memory retrieval in the appropriate context in AD mice when compared with control (Ctrl) mice. Moreover, optogenetic stimulation facilitated reactivation of the neural ensembles that were previously activated during memory encoding. These data suggest that activating previously learned DG memory traces can rescue cognitive impairments and point to DG manipulation as a potential target to treat memory loss commonly seen in AD. © 2017 Wiley Periodicals, Inc.

The computational nature of memory modification

PubMed Central

Gershman, Samuel J; Monfils, Marie-H; Norman, Kenneth A; Niv, Yael

2017-01-01

Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature. DOI: http://dx.doi.org/10.7554/eLife.23763.001 PMID:28294944

Emotion strengthens high-priority memory traces but weakens low-priority memory traces.

PubMed

Sakaki, Michiko; Fryer, Kellie; Mather, Mara

2014-02-01

When people encounter emotional events, their memory for those events is typically enhanced. But it has been unclear how emotionally arousing events influence memory for preceding information. Does emotional arousal induce retrograde amnesia or retrograde enhancement? The current study revealed that this depends on the top-down goal relevance of the preceding information. Across three studies, we found that emotional arousal induced by one image facilitated memory for the preceding neutral item when people prioritized that neutral item. In contrast, an emotionally arousing image impaired memory for the preceding neutral item when people did not prioritize that neutral item. Emotional arousal elicited by both negative and positive pictures showed this pattern of enhancing or impairing memory for the preceding stimulus depending on its priority. These results indicate that emotional arousal amplifies the effects of top-down priority in memory formation.

Impact of encoding depth on awareness of perceptual effects in recognition memory.

PubMed

Gardiner, J M; Gregg, V H; Mashru, R; Thaman, M

2001-04-01

Pictorial stimuli are more likely to be recognized if they are the same size, rather than a different size, at study and at test. This size congruency effect was replicated in two experiments in which the encoding variables were respectively undivided versus divided attention and level of processing. In terms of performance, these variables influenced recognition and did not influence size congruency effects. But in terms of awareness, measured by remember and know responses, these variables did influence size congruency effects. With undivided attention and with a deep level of processing, size congruency effects occurred only in remembering. With divided attention and with a shallow level of processing, size congruency effects occurred only in knowing. The results show that effects that occur in remembering may also occur independently in knowing. They support theories in which remembering and knowing reflect different memory processes or systems. They do not support the theory that remembering and knowing reflect differences in trace strength.

The "subjective" pupil old/new effect: is the truth plain to see?

PubMed

Montefinese, Maria; Ambrosini, Ettore; Fairfield, Beth; Mammarella, Nicola

2013-07-01

Human memory is an imperfect process, prone to distortion and errors that range from minor disturbances to major errors that can have serious consequences on everyday life. In this study, we investigated false remembering of manipulatory verbs using an explicit recognition task and pupillometry. Our results replicated the "classical" pupil old/new effect as well as data in false remembering literature that show how items must be recognize as old in order for the pupil size to increase (e.g., "subjective" pupil old/new effect), even though these items do not necessarily have to be truly old. These findings support the strength-of-memory trace account that affirms that pupil dilation is related to experience rather than to the accuracy of recognition. Moreover, behavioral results showed higher rates of true and false recognitions for manipulatory verbs and a consequent larger pupil diameter, supporting the embodied view of language. Copyright © 2013 Elsevier B.V. All rights reserved.

Neural correlates of confidence during item recognition and source memory retrieval: evidence for both dual-process and strength memory theories.

PubMed

Hayes, Scott M; Buchler, Norbou; Stokes, Jared; Kragel, James; Cabeza, Roberto

2011-12-01

Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength process (strength theory). To investigate these issues, the current fMRI study measured activity during retrieval of memories that differed quantitatively in terms of strength (high vs. low-confidence trials) and qualitatively in terms of recollection versus familiarity (source vs. item memory tasks). Support for each theory varied depending on which node of the episodic memory network was considered. Results from MTL best fit a dual-process account, as a dissociation was found between a right hippocampal region showing high-confidence activity during the source memory task and bilateral rhinal regions showing high-confidence activity during the item memory task. Within PFC, several left-lateralized regions showed greater activity for source than item memory, consistent with recollective orienting, whereas a right-lateralized ventrolateral area showed low-confidence activity in both tasks, consistent with monitoring processes. Parietal findings were generally consistent with strength theory, with dorsal areas showing low-confidence activity and ventral areas showing high-confidence activity in both tasks. This dissociation fits with an attentional account of parietal functions during episodic retrieval. The results suggest that both dual-process and strength theories are partly correct, highlighting the need for an integrated model that links to more general cognitive theories to account for observed neural activity during episodic memory retrieval.

Neural Correlates of Confidence during Item Recognition and Source Memory Retrieval: Evidence for Both Dual-process and Strength Memory Theories

PubMed Central

Hayes, Scott M.; Buchler, Norbou; Stokes, Jared; Kragel, James; Cabeza, Roberto

2012-01-01

Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength process (strength theory). To investigate these issues, the current fMRI study measured activity during retrieval of memories that differed quantitatively in terms of strength (high vs. low-confidence trials) and qualitatively in terms of recollection versus familiarity (source vs. item memory tasks). Support for each theory varied depending on which node of the episodic memory network was considered. Results from MTL best fit a dual-process account, as a dissociation was found between a right hippocampal region showing high-confidence activity during the source memory task and bilateral rhinal regions showing high-confidence activity during the item memory task. Within PFC, several left-lateralized regions showed greater activity for source than item memory, consistent with recollective orienting, whereas a right-lateralized ventrolateral area showed low-confidence activity in both tasks, consistent with monitoring processes. Parietal findings were generally consistent with strength theory, with dorsal areas showing low-confidence activity and ventral areas showing high-confidence activity in both tasks. This dissociation fits with an attentional account of parietal functions during episodic retrieval. The results suggest that both dual-process and strength theories are partly correct, highlighting the need for an integrated model that links to more general cognitive theories to account for observed neural activity during episodic memory retrieval. PMID:21736454

Memory Skills of Deaf Learners: Implications and Applications

ERIC Educational Resources Information Center

Hamilton, Harley

2011-01-01

The author reviews research on working memory and short-term memory abilities of deaf individuals, delineating strengths and weaknesses. Among the areas of weakness that are reviewed are sequential recall, processing speed, attention, and memory load. Areas of strengths include free recall, visuospatial recall, imagery, and dual encoding.…

Putting congeniality effects into context: Investigating the role of context in attitude memory using multiple paradigms.

PubMed

Waldum, Emily R; Sahakyan, Lili

2012-05-01

In three experiments, we evaluated remembering and intentional forgetting of attitude statements that were either congruent or incongruent with participants' own political attitudes. In Experiment 1, significant directed forgetting was obtained for incongruent statements, but not for congruent statements. In addition, in the remember group, recall was better for incongruent statements than congruent statements. To explain these findings, we propose a contextual competition at retrieval hypothesis, according to which incongruent statements become more strongly associated with their episodic context during encoding than do congruent statements. At the time of retrieval, incongruent statements compete with congruent statements due to the greater amount of contextual information stored in their memory trace. We tested this hypothesis in Experiment 2 by studying free recall of congruent and incongruent statements in a mixed-pure list design. In Experiment 3, memory for incongruent and congruent statements was tested under recognition test conditions that varied in terms of how much direct retrieval of contextual details they required. Overall, the results supported the contextual competition hypothesis, and they indicate the importance of context strength in both the remembering and intentional forgetting of attitude information.

Putting congeniality effects into context: Investigating the role of context in attitude memory using multiple paradigms

PubMed Central

Waldum, Emily R; Sahakyan, Lili

2013-01-01

In three experiments, we evaluated remembering and intentional forgetting of attitude statements that were either congruent or incongruent with participants’ own political attitudes. In Experiment 1, significant directed forgetting was obtained for incongruent statements, but not for congruent statements. In addition, in the remember group, recall was better for incongruent statements than congruent statements. To explain these findings, we propose a contextual competition at retrieval hypothesis, according to which incongruent statements become more strongly associated with their episodic context during encoding than do congruent statements. At the time of retrieval, incongruent statements compete with congruent statements due to the greater amount of contextual information stored in their memory trace. We tested this hypothesis in Experiment 2 by studying free recall of congruent and incongruent statements in a mixed-pure list design. In Experiment 3, memory for incongruent and congruent statements was tested under recognition test conditions that varied in terms of how much direct retrieval of contextual details they required. Overall, the results supported the contextual competition hypothesis, and they indicate the importance of context strength in both the remembering and intentional forgetting of attitude information. PMID:23440945

Memories of Holocaust-related traumatic experiences, sense of coherence, and survivors' subjective well-being in late life: some puzzling findings.

PubMed

Zeidner, Moshe; Aharoni-David, Eynat

2015-01-01

This study explores the nexus of relationships between memories of Holocaust-related early traumatic events, survivors' sense of coherence (SOC), and subjective well-being (SWB) in late life. The basic design of this study, based 106 survivors (54% female), was cross-sectional. Participants underwent an extensive in-depth clinical interview relating to their Holocaust experiences and responded to measures of SOC and SWB. These data provided no evidence for the moderating or "buffering" effect of SOC but showed support for indirect effects of SOC in the relationship between memory traces of specific traumatic experiences and adaptive outcomes. The results of the present study provide support for Antonovsky's salutogenic perspective. It is highly plausible that survivors who underwent severe experiences during the Holocaust period were forced to call upon all their inner strengths and coping resources,and that their success in doing so and also surviving this horrendous period, might have contributed to the development of a stronger sense of meaning and coherence, which, in turn lead to a better sense of mental health as they approach the final season of their lives.

[Analysis of intrusion errors in free recall].

PubMed

Diesfeldt, H F A

2017-06-01

Extra-list intrusion errors during five trials of the eight-word list-learning task of the Amsterdam Dementia Screening Test (ADST) were investigated in 823 consecutive psychogeriatric patients (87.1% suffering from major neurocognitive disorder). Almost half of the participants (45.9%) produced one or more intrusion errors on the verbal recall test. Correct responses were lower when subjects made intrusion errors, but learning slopes did not differ between subjects who committed intrusion errors and those who did not so. Bivariate regression analyses revealed that participants who committed intrusion errors were more deficient on measures of eight-word recognition memory, delayed visual recognition and tests of executive control (the Behavioral Dyscontrol Scale and the ADST-Graphical Sequences as measures of response inhibition). Using hierarchical multiple regression, only free recall and delayed visual recognition retained an independent effect in the association with intrusion errors, such that deficient scores on tests of episodic memory were sufficient to explain the occurrence of intrusion errors. Measures of inhibitory control did not add significantly to the explanation of intrusion errors in free recall, which makes insufficient strength of memory traces rather than a primary deficit in inhibition the preferred account for intrusion errors in free recall.

Trace and contextual fear conditioning require neural activity and NMDA receptor-dependent transmission in the medial prefrontal cortex

PubMed Central

Gilmartin, Marieke R.; Helmstetter, Fred J.

2010-01-01

The contribution of the medial prefrontal cortex (mPFC) to the formation of memory is a subject of considerable recent interest. Notably, the mechanisms supporting memory acquisition in this structure are poorly understood. The mPFC has been implicated in the acquisition of trace fear conditioning, a task that requires the association of a conditional stimulus (CS) and an aversive unconditional stimulus (UCS) across a temporal gap. In both rat and human subjects, frontal regions show increased activity during the trace interval separating the CS and UCS. We investigated the contribution of prefrontal neural activity in the rat to the acquisition of trace fear conditioning using microinfusions of the γ-aminobutyric acid type A (GABAA) receptor agonist muscimol. We also investigated the role of prefrontal N-methyl-d-aspartate (NMDA) receptor-mediated signaling in trace fear conditioning using the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (APV). Temporary inactivation of prefrontal activity with muscimol or blockade of NMDA receptor-dependent transmission in mPFC impaired the acquisition of trace, but not delay, conditional fear responses. Simultaneously acquired contextual fear responses were also impaired in drug-treated rats exposed to trace or delay, but not unpaired, training protocols. Our results support the idea that synaptic plasticity within the mPFC is critical for the long-term storage of memory in trace fear conditioning. PMID:20504949

Incidental Memory Encoding Assessed with Signal Detection Theory and Functional Magnetic Resonance Imaging (fMRI).

PubMed

Clemens, Benjamin; Regenbogen, Christina; Koch, Kathrin; Backes, Volker; Romanczuk-Seiferth, Nina; Pauly, Katharina; Shah, N Jon; Schneider, Frank; Habel, Ute; Kellermann, Thilo

2015-01-01

In functional magnetic resonance imaging (fMRI) studies that apply a "subsequent memory" approach, successful encoding is indicated by increased fMRI activity during the encoding phase for hits vs. misses, in areas underlying memory encoding such as the hippocampal formation. Signal-detection theory (SDT) can be used to analyze memory-related fMRI activity as a function of the participant's memory trace strength (d(')). The goal of the present study was to use SDT to examine the relationship between fMRI activity during incidental encoding and participants' recognition performance. To implement a new approach, post-experimental group assignment into High- or Low Performers (HP or LP) was based on 29 healthy participants' recognition performance, assessed with SDT. The analyses focused on the interaction between the factors group (HP vs. LP) and recognition performance (hits vs. misses). A whole-brain analysis revealed increased activation for HP vs. LP during incidental encoding for remembered vs. forgotten items (hits > misses) in the insula/temporo-parietal junction (TPJ) and the fusiform gyrus (FFG). Parameter estimates in these regions exhibited a significant positive correlation with d('). As these brain regions are highly relevant for salience detection (insula), stimulus-driven attention (TPJ), and content-specific processing of mnemonic stimuli (FFG), we suggest that HPs' elevated memory performance was associated with enhanced attentional and content-specific sensory processing during the encoding phase. We provide first correlative evidence that encoding-related activity in content-specific sensory areas and content-independent attention and salience detection areas influences memory performance in a task with incidental encoding of facial stimuli. Based on our findings, we discuss whether the aforementioned group differences in brain activity during incidental encoding might constitute the basis of general differences in memory performance between HP and LP.

Monkeys have a limited form of short-term memory in audition

PubMed Central

Scott, Brian H.; Mishkin, Mortimer; Yin, Pingbo

2012-01-01

A stimulus trace may be temporarily retained either actively [i.e., in working memory (WM)] or by the weaker mnemonic process we will call passive short-term memory, in which a given stimulus trace is highly susceptible to “overwriting” by a subsequent stimulus. It has been suggested that WM is the more robust process because it exploits long-term memory (i.e., a current stimulus activates a stored representation of that stimulus, which can then be actively maintained). Recent studies have suggested that monkeys may be unable to store acoustic signals in long-term memory, raising the possibility that they may therefore also lack auditory WM. To explore this possibility, we tested rhesus monkeys on a serial delayed match-to-sample (DMS) task using a small set of sounds presented with ∼1-s interstimulus delays. Performance was accurate whenever a match or a nonmatch stimulus followed the sample directly, but it fell precipitously if a single nonmatch stimulus intervened between sample and match. The steep drop in accuracy was found to be due not to passive decay of the sample’s trace, but to retroactive interference from the intervening nonmatch stimulus. This “overwriting” effect was far greater than that observed previously in serial DMS with visual stimuli. The results, which accord with the notion that WM relies on long-term memory, indicate that monkeys perform serial DMS in audition remarkably poorly and that whatever success they had on this task depended largely, if not entirely, on the retention of stimulus traces in the passive form of short-term memory. PMID:22778411

Monkeys have a limited form of short-term memory in audition.

PubMed

Scott, Brian H; Mishkin, Mortimer; Yin, Pingbo

2012-07-24

A stimulus trace may be temporarily retained either actively [i.e., in working memory (WM)] or by the weaker mnemonic process we will call passive short-term memory, in which a given stimulus trace is highly susceptible to "overwriting" by a subsequent stimulus. It has been suggested that WM is the more robust process because it exploits long-term memory (i.e., a current stimulus activates a stored representation of that stimulus, which can then be actively maintained). Recent studies have suggested that monkeys may be unable to store acoustic signals in long-term memory, raising the possibility that they may therefore also lack auditory WM. To explore this possibility, we tested rhesus monkeys on a serial delayed match-to-sample (DMS) task using a small set of sounds presented with ~1-s interstimulus delays. Performance was accurate whenever a match or a nonmatch stimulus followed the sample directly, but it fell precipitously if a single nonmatch stimulus intervened between sample and match. The steep drop in accuracy was found to be due not to passive decay of the sample's trace, but to retroactive interference from the intervening nonmatch stimulus. This "overwriting" effect was far greater than that observed previously in serial DMS with visual stimuli. The results, which accord with the notion that WM relies on long-term memory, indicate that monkeys perform serial DMS in audition remarkably poorly and that whatever success they had on this task depended largely, if not entirely, on the retention of stimulus traces in the passive form of short-term memory.

Tracing Donor-MHC Class II Reactive B cells in Mouse Cardiac Transplantation: Delayed CTLA4-Ig Treatment Prevents Memory Alloreactive B-Cell Generation.

PubMed

Yang, Jinghui; Chen, Jianjun; Young, James S; Wang, Qiang; Yin, Dengping; Sciammas, Roger; Chong, Anita S

2016-08-01

The dual role of B cells as drivers and suppressors of the immune responses have underscored the need to trace the fate of B cells recognizing donor major histocompatibility complex class I and class II after allograft transplantation. In this study, we used donor class II tetramers to trace the fate of I-E-specific B cells after immunization with BALB/c spleen cells or cardiac transplantation, in naive or sensitized C57BL/6 recipients. We combined this approach with genetic lineage tracing of memory B cells in activation-induced cytidine deaminase regulated Cre transgenic mice crossed to the ROSA26-enhanced yellow fluorescent protein reporter mice to track endogenous I-E-specific memory B cell generation. Immunization with BALB/c splenocytes or heart transplantation induced an expansion and differentiation of I-E-specific B cells into germinal center B cells, whereas BALB/c heart transplantation into sensitized recipients induced the preferential differentiation into antibody-secreting cells. A 10.8-fold increase in the frequency of I-E-specific memory B cells was observed by day 42 postimmunization. Treatment with CTLA4-Ig starting on day 0 or day 7 postimmunization abrogated I-E-specific memory B cell generation and sensitized humoral responses, but not if treatment commenced on day 14. The majority of donor-specific memory B cells are generated between days 7 and 14 postimmunization, thus revealing a flexible timeframe whereby delayed CTLA4-Ig administration can inhibit sensitization and the generation of memory graft-reactive B cells.

Retrograde Amnesia for Episodic and Semantic Memories in Amnestic Mild Cognitive Impairment.

PubMed

De Simone, Maria Stefania; Fadda, Lucia; Perri, Roberta; De Tollis, Massimo; Aloisi, Marta; Caltagirone, Carlo; Carlesimo, Giovanni Augusto

2017-01-01

Retrograde amnesia (RA), which includes loss of memory for past personal events (autobiographical RA) and for acquired knowledge (semantic RA), has been largely documented in patients with amnestic mild cognitive impairment (aMCI). However, previous studies have produced controversial results particularly concerning the temporal extent of memory impairment. Here we investigated whether, with the onset of hippocampal pathology, age of memory acquisition and retrieval frequency play different roles in modulating the progressive loss of semantic and episodic contents of retrograde memory respectively. For this purpose, aMCI patients and healthy controls were tested for the ability to recall semantic and autobiographical information related to famous public events as a function of both age of acquisition and retrieval frequency. In aMCI patients, we found that the impairment in recollecting past personal incidents was modulated by the combined action of memory age and retrieval frequency, because older and more frequently retrieved episodes are less susceptible to loss than more recent and less frequently retrieved ones. On the other side, we found that the loss of semantic information depended only on memory age, because the remoteness of the trace allows for better preservation of the memory. Our results provide evidence that the loss of the two components of retrograde memory is regulated by different mechanisms. This supports the view that diverse neural mechanisms are involved in episodic and semantic memory trace storage and retrieval, as postulated by the Multiple Trace Theory.

Hippocampus and Medial Prefrontal Cortex Contributions to Trace and Contextual Fear Memory Expression over Time

ERIC Educational Resources Information Center

Beeman, Christopher L.; Bauer, Philip S.; Pierson, Jamie L.; Quinn, Jennifer J.

2013-01-01

Previous work has shown that damage to the dorsal hippocampus (DH) occurring at recent, but not remote, timepoints following acquisition produces a deficit in trace conditioned fear memory expression. The opposite pattern has been observed with lesions to the medial prefrontal cortex (mPFC). The present studies address: (1) whether these lesion…

Memory for Verbally Presented Routes: A Comparison of Strategies Used by Blind and Sighted People.

ERIC Educational Resources Information Center

Easton, R. D.; Bentzen, B. L.

1987-01-01

Congenitally-blind (N=16) and sighted (N=16) young adults listened to descriptions of routes and then finger traced routes through a raised line matrix. Route tracing speed and accuracy revealed that spatial sentence verification interfered with route memory more than abstract/verbal sentence verification for all subjects. (Author/CB)

Traces of Memory for a Lost Childhood Language: The Savings Paradigm Expanded

ERIC Educational Resources Information Center

Isurin, Ludmila; Seidel, Christy

2015-01-01

The loss of a childhood language, especially in adoptees, has attracted scholars' attention in the past, but a search for any memory traces has yielded conflicting results. In a psycholinguistic tradition known as the savings paradigm, a learn-and-relearn technique is employed to examine whether the relearning of lexical items once known, often in…

Quantitative evaluation of learning and memory trace in studies of mnemotropic effects of immunotropic drugs.

PubMed

Kiseleva, N M; Novoseletskaya, A V; Voevodina, Ye B; Kozlov, I G; Inozemtsev, A N

2012-12-01

Apart from restoration of disordered immunological parameters, tactivin and derinat exhibit a pronounced effect on the higher integrative functions of the brain. Experiments on Wistar rats have shown that these drugs accelerated conditioning of food and defense responses. New methods for quantitative evaluation of memory trace consolidation are proposed.

Strength and Aerobic Exercises Improve Spatial Memory in Aging Rats Through Stimulating Distinct Neuroplasticity Mechanisms.

PubMed

Vilela, Thais Ceresér; Muller, Alexandre Pastoris; Damiani, Adriani Paganini; Macan, Tamires Pavei; da Silva, Sabrina; Canteiro, Paula Bortoluzzi; de Sena Casagrande, Alisson; Pedroso, Giulia Dos Santos; Nesi, Renata Tiscoski; de Andrade, Vanessa Moraes; de Pinho, Ricardo Aurino

2017-12-01

Aging is associated with impaired cognition and memory and increased susceptibility to neurodegenerative disorders. Physical exercise is neuroprotective; however, the major evidence of this effect involves studies of only aerobic training in young animals. The benefits of other exercise protocols such as strength training in aged animals remains unknown. Here, we investigated the effect of aerobic and strength training on spatial memory and hippocampal plasticity in aging rats. Aging Wistar rats performed aerobic or strength training for 50 min 3 to 4 days/week for 8 weeks. Spatial memory and neurotrophic and glutamatergic signaling in the hippocampus of aged rats were evaluated after aerobic or strength training. Both aerobic and strength training improved cognition during the performance of a spatial memory task. Remarkably, the improvement in spatial memory was accompanied by an increase in synaptic plasticity proteins within the hippocampus after exercise training, with some differences in the intracellular functions of those proteins between the two exercise protocols. Moreover, neurotrophic signaling (CREB, BDNF, and the P75 NTR receptor) increased after training for both exercise protocols, and aerobic exercise specifically increased glutamatergic proteins (NMDA receptor and PSD-95). We also observed a decrease in DNA damage after aerobic training. In contrast, strength training increased levels of PKCα and the proinflammatory factors TNF-α and IL-1β. Overall, our results show that both aerobic and strength training improved spatial memory in aging rats through inducing distinct molecular mechanisms of neuroplasticity. Our findings extend the idea that exercise protocols can be used to improve cognition during aging.

Sleep in Children Enhances Preferentially Emotional Declarative But Not Procedural Memories

ERIC Educational Resources Information Center

Prehn-Kristensen, Alexander; Goder, Robert; Chirobeja, Stefania; Bressman, Inka; Ferstl, Roman; Baving, Lioba

2009-01-01

Although the consolidation of several memory systems is enhanced by sleep in adults, recent studies suggest that sleep supports declarative memory but not procedural memory in children. In the current study, the influence of sleep on emotional declarative memory (recognition task) and procedural memory (mirror tracing task) in 20 healthy children…

Medial Temporal Lobe Activity during Source Retrieval Reflects Information Type, Not Memory Strength

ERIC Educational Resources Information Center

Diana, Rachel A.; Yonelinas, Andrew P.; Ranganath, Charan

2010-01-01

The medial temporal lobes (MTLs) are critical for episodic memory but the functions of MTL subregions are controversial. According to memory strength theory, MTL subregions collectively support declarative memory in a graded manner. In contrast, other theories assert that MTL subregions support functionally distinct processes. For instance, one…

A Temporal Ratio Model of Memory

ERIC Educational Resources Information Center

Brown, Gordon D. A.; Neath, Ian; Chater, Nick

2007-01-01

A model of memory retrieval is described. The model embodies four main claims: (a) temporal memory--traces of items are represented in memory partly in terms of their temporal distance from the present; (b) scale-similarity--similar mechanisms govern retrieval from memory over many different timescales; (c) local distinctiveness--performance on a…

The Development of Metamemory Monitoring during Retrieval: The Case of Memory Strength and Memory Absence

ERIC Educational Resources Information Center

Ghetti, Simona; Lyons, Kristen E.; Lazzarin, Federica; Cornoldi, Cesare

2008-01-01

This research examined the development of the ability to monitor memory strength and memory absence at retrieval. In two experiments, 7-year-olds, 10-year-olds, and adults enacted and imagined enacting a series of bizarre and common actions. Two weeks later, they completed a memory test in which they were asked to determine whether each action had…

Attention, working memory, and phenomenal experience of WM content: memory levels determined by different types of top-down modulation.

PubMed

Jacob, Jane; Jacobs, Christianne; Silvanto, Juha

2015-01-01

What is the role of top-down attentional modulation in consciously accessing working memory (WM) content? In influential WM models, information can exist in different states, determined by allocation of attention; placing the original memory representation in the center of focused attention gives rise to conscious access. Here we discuss various lines of evidence indicating that such attentional modulation is not sufficient for memory content to be phenomenally experienced. We propose that, in addition to attentional modulation of the memory representation, another type of top-down modulation is required: suppression of all incoming visual information, via inhibition of early visual cortex. In this view, there are three distinct memory levels, as a function of the top-down control associated with them: (1) Nonattended, nonconscious associated with no attentional modulation; (2) attended, phenomenally nonconscious memory, associated with attentional enhancement of the actual memory trace; (3) attended, phenomenally conscious memory content, associated with enhancement of the memory trace and top-down suppression of all incoming visual input.

A new intuitionism: Meaning, memory, and development in Fuzzy-Trace Theory

PubMed Central

Reyna, Valerie F.

2014-01-01

Combining meaning, memory, and development, the perennially popular topic of intuition can be approached in a new way. Fuzzy-trace theory integrates these topics by distinguishing between meaning-based gist representations, which support fuzzy (yet advanced) intuition, and superficial verbatim representations of information, which support precise analysis. Here, I review the counterintuitive findings that led to the development of the theory and its most recent extensions to the neuroscience of risky decision making. These findings include memory interference (worse verbatim memory is associated with better reasoning); nonnumerical framing (framing effects increase when numbers are deleted from decision problems); developmental decreases in gray matter and increases in brain connectivity; developmental reversals in memory, judgment, and decision making (heuristics and biases based on gist increase from childhood to adulthood, challenging conceptions of rationality); and selective attention effects that provide critical tests comparing fuzzy-trace theory, expected utility theory, and its variants (e.g., prospect theory). Surprising implications for judgment and decision making in real life are also discussed, notably, that adaptive decision making relies mainly on gist-based intuition in law, medicine, and public health. PMID:25530822

A new intuitionism: Meaning, memory, and development in Fuzzy-Trace Theory.

PubMed

Reyna, Valerie F

2012-05-01

Combining meaning, memory, and development, the perennially popular topic of intuition can be approached in a new way. Fuzzy-trace theory integrates these topics by distinguishing between meaning-based gist representations, which support fuzzy (yet advanced) intuition, and superficial verbatim representations of information, which support precise analysis. Here, I review the counterintuitive findings that led to the development of the theory and its most recent extensions to the neuroscience of risky decision making. These findings include memory interference (worse verbatim memory is associated with better reasoning); nonnumerical framing (framing effects increase when numbers are deleted from decision problems); developmental decreases in gray matter and increases in brain connectivity; developmental reversals in memory, judgment, and decision making (heuristics and biases based on gist increase from childhood to adulthood, challenging conceptions of rationality); and selective attention effects that provide critical tests comparing fuzzy-trace theory, expected utility theory, and its variants (e.g., prospect theory). Surprising implications for judgment and decision making in real life are also discussed, notably, that adaptive decision making relies mainly on gist-based intuition in law, medicine, and public health.

Scopolamine Impairs Appetitive But Not Aversive Trace Conditioning: Role of the Medial Prefrontal Cortex.

PubMed

Pezze, Marie-Astrid; Marshall, Hayley J; Cassaday, Helen J

2017-06-28

The muscarinic acetylcholine receptor is an important modulator of medial prefrontal cortex (mPFC) functions, such as the working memory required to bridge a trace interval in associative leaning. Aversive and appetitive trace conditioning procedures were used to examine the effects of scopolamine (0.1 and 0.5 mg/kg, i.p.) in male rats. Follow-up experiments tested the effects of microinfusion of 0.15 μg of scopolamine (0.075 μg of in 0.5 μl/side) in infralimbic (IL) versus prelimbic regions of rat mPFC, in appetitive trace and locomotor activity (LMA) procedures. Systemic scopolamine was without effect in an aversive trace conditioning procedure, but impaired appetitive conditioning at a 2 s trace interval. This effect was demonstrated as reduced responding during presentations of the conditioned stimulus (CS) and during the interstimulus interval (ISI). There was no such effect on responding during food (unconditioned stimulus, US) responding or in the intertrial interval (ITI). In contrast, systemic scopolamine dose-relatedly increased LMA. Trace conditioning was similarly impaired at the 2 s trace (shown as reduced responding to the CS and during the ISI, but not during US presentations or in the ITI) after infusion in mPFC, whereas LMA was increased (after infusion in IL only). Therefore, our results point to the importance of cholinergic modulation in mPFC for trace conditioning and show that the observed effects cannot be attributed to reduced activity. SIGNIFICANCE STATEMENT Events are very often separated in time, in which case working memory is necessary to condition their association in "trace conditioning." The present study used conditioning variants motivated aversively with foot shock and appetitively with food. The drug scopolamine was used to block muscarinic acetylcholine receptors involved in working memory. The results show that reduced cholinergic transmission in medial prefrontal cortex (mPFC) impaired appetitive trace conditioning at a 2 s trace interval. However, scopolamine was without effect in the aversive procedure, revealing the importance of procedural differences to the demonstration of the drug effect. The finding that blockade of muscarinic receptors in mPFC impaired trace conditioning shows that these receptors are critical modulators of short-term working memory. Copyright © 2017 Pezze et al.

Scopolamine Impairs Appetitive But Not Aversive Trace Conditioning: Role of the Medial Prefrontal Cortex

PubMed Central

Pezze, Marie-Astrid; Marshall, Hayley J.

2017-01-01

The muscarinic acetylcholine receptor is an important modulator of medial prefrontal cortex (mPFC) functions, such as the working memory required to bridge a trace interval in associative leaning. Aversive and appetitive trace conditioning procedures were used to examine the effects of scopolamine (0.1 and 0.5 mg/kg, i.p.) in male rats. Follow-up experiments tested the effects of microinfusion of 0.15 μg of scopolamine (0.075 μg of in 0.5 μl/side) in infralimbic (IL) versus prelimbic regions of rat mPFC, in appetitive trace and locomotor activity (LMA) procedures. Systemic scopolamine was without effect in an aversive trace conditioning procedure, but impaired appetitive conditioning at a 2 s trace interval. This effect was demonstrated as reduced responding during presentations of the conditioned stimulus (CS) and during the interstimulus interval (ISI). There was no such effect on responding during food (unconditioned stimulus, US) responding or in the intertrial interval (ITI). In contrast, systemic scopolamine dose-relatedly increased LMA. Trace conditioning was similarly impaired at the 2 s trace (shown as reduced responding to the CS and during the ISI, but not during US presentations or in the ITI) after infusion in mPFC, whereas LMA was increased (after infusion in IL only). Therefore, our results point to the importance of cholinergic modulation in mPFC for trace conditioning and show that the observed effects cannot be attributed to reduced activity. SIGNIFICANCE STATEMENT Events are very often separated in time, in which case working memory is necessary to condition their association in “trace conditioning.” The present study used conditioning variants motivated aversively with foot shock and appetitively with food. The drug scopolamine was used to block muscarinic acetylcholine receptors involved in working memory. The results show that reduced cholinergic transmission in medial prefrontal cortex (mPFC) impaired appetitive trace conditioning at a 2 s trace interval. However, scopolamine was without effect in the aversive procedure, revealing the importance of procedural differences to the demonstration of the drug effect. The finding that blockade of muscarinic receptors in mPFC impaired trace conditioning shows that these receptors are critical modulators of short-term working memory. PMID:28559376

Rethinking Inhibition Theory: On the Problematic Status of the Inhibition Theory for Forgetting

ERIC Educational Resources Information Center

Raaijmakers, Jeroen G. W.; Jakab, Emoke

2013-01-01

The standard textbook account of interference and forgetting is based on the assumption that retrieval of a memory trace is affected by competition by other memory traces. In recent years, a number of researchers have questioned this view and have proposed an alternative account of forgetting based on a mechanism of suppression. In this inhibition…

The dynamic time course of memory recovery in transient global amnesia.

PubMed

Guillery-Girard, B; Desgranges, B; Urban, C; Piolino, P; de la Sayette, V; Eustache, F

2004-11-01

To investigate the dynamic time course of transient global amnesia (TGA)--that is, the process of recovery and the interindividual variability--by testing four patients during the day of TGA itself (on three occasions) and at follow up (on two occasions). A specially designed protocol focusing on semantic (both conceptual and autobiographical knowledge) and episodic (both anterograde and retrograde components) memory. Every patient showed marked impairment of both anterograde and retrograde episodic memory during the acute phase, with a relative preservation of personal and conceptual semantic knowledge. During the following phase, the authors observed similarities and differences among the patients' patterns of recovery. In general, retrograde amnesia recovered before the anterograde amnesia and anterograde episodic memory was recovered gradually in every case. In contrast, shrinkage of retrograde amnesia was more heterogeneous. In two of the patients, this shrinkage followed a chronological gradient and the most remote events were recovered first. In the two other patients, it depended more on the strength of the trace, and there was no temporal gradient. For the latter, an executive deficit could account for difficulties in accessing both conceptual knowledge and autobiographical memories. This profile of recovery suggests a "neocortical to medial temporal" process in every case, and the possibility of an additional frontal dysfunction in some cases. Hence, the acute phase seems to be characterised by a common episodic impairment. This variability between subjects appears in the recovery phase with two different patterns of impairment.

An instance theory of associative learning.

PubMed

Jamieson, Randall K; Crump, Matthew J C; Hannah, Samuel D

2012-03-01

We present and test an instance model of associative learning. The model, Minerva-AL, treats associative learning as cued recall. Memory preserves the events of individual trials in separate traces. A probe presented to memory contacts all traces in parallel and retrieves a weighted sum of the traces, a structure called the echo. Learning of a cue-outcome relationship is measured by the cue's ability to retrieve a target outcome. The theory predicts a number of associative learning phenomena, including acquisition, extinction, reacquisition, conditioned inhibition, external inhibition, latent inhibition, discrimination, generalization, blocking, overshadowing, overexpectation, superconditioning, recovery from blocking, recovery from overshadowing, recovery from overexpectation, backward blocking, backward conditioned inhibition, and second-order retrospective revaluation. We argue that associative learning is consistent with an instance-based approach to learning and memory.

Oscillatory mechanisms of process binding in memory.

PubMed

Klimesch, Wolfgang; Freunberger, Roman; Sauseng, Paul

2010-06-01

A central topic in cognitive neuroscience is the question, which processes underlie large scale communication within and between different neural networks. The basic assumption is that oscillatory phase synchronization plays an important role for process binding--the transient linking of different cognitive processes--which may be considered a special type of large scale communication. We investigate this question for memory processes on the basis of different types of oscillatory synchronization mechanisms. The reviewed findings suggest that theta and alpha phase coupling (and phase reorganization) reflect control processes in two large memory systems, a working memory and a complex knowledge system that comprises semantic long-term memory. It is suggested that alpha phase synchronization may be interpreted in terms of processes that coordinate top-down control (a process guided by expectancy to focus on relevant search areas) and access to memory traces (a process leading to the activation of a memory trace). An analogous interpretation is suggested for theta oscillations and the controlled access to episodic memories. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Newly-formed emotional memories guide selective attention processes: Evidence from event-related potentials.

PubMed

Schupp, Harald T; Kirmse, Ursula; Schmälzle, Ralf; Flaisch, Tobias; Renner, Britta

2016-06-20

Emotional cues can guide selective attention processes. However, emotional stimuli can both activate long-term memory representations reflecting general world knowledge and engage newly formed memory representations representing specific knowledge from the immediate past. Here, the self-completion feature of associative memory was utilized to assess the regulation of attention processes by newly-formed emotional memory. First, new memory representations were formed by presenting pictures depicting a person either in an erotic pose or as a portrait. Afterwards, to activate newly-built memory traces, edited pictures were presented showing only the head region of the person. ERP recordings revealed the emotional regulation of attention by newly-formed memories. Specifically, edited pictures from the erotic compared to the portrait category elicited an early posterior negativity and late positive potential, similar to the findings observed for the original pictures. A control condition showed that the effect was dependent on newly-formed memory traces. Given the large number of new memories formed each day, they presumably make an important contribution to the regulation of attention in everyday life.

Newly-formed emotional memories guide selective attention processes: Evidence from event-related potentials

PubMed Central

Schupp, Harald T.; Kirmse, Ursula; Schmälzle, Ralf; Flaisch, Tobias; Renner, Britta

2016-01-01

Emotional cues can guide selective attention processes. However, emotional stimuli can both activate long-term memory representations reflecting general world knowledge and engage newly formed memory representations representing specific knowledge from the immediate past. Here, the self-completion feature of associative memory was utilized to assess the regulation of attention processes by newly-formed emotional memory. First, new memory representations were formed by presenting pictures depicting a person either in an erotic pose or as a portrait. Afterwards, to activate newly-built memory traces, edited pictures were presented showing only the head region of the person. ERP recordings revealed the emotional regulation of attention by newly-formed memories. Specifically, edited pictures from the erotic compared to the portrait category elicited an early posterior negativity and late positive potential, similar to the findings observed for the original pictures. A control condition showed that the effect was dependent on newly-formed memory traces. Given the large number of new memories formed each day, they presumably make an important contribution to the regulation of attention in everyday life. PMID:27321471

Slow-Wave Sleep-Imposed Replay Modulates Both Strength and Precision of Memory

PubMed Central

2014-01-01

Odor perception is hypothesized to be an experience-dependent process involving the encoding of odor objects by distributed olfactory cortical ensembles. Olfactory cortical neurons coactivated by a specific pattern of odorant evoked input become linked through association fiber synaptic plasticity, creating a template of the familiar odor. In this way, experience and memory play an important role in odor perception and discrimination. In other systems, memory consolidation occurs partially via slow-wave sleep (SWS)-dependent replay of activity patterns originally evoked during waking. SWS is ideal for replay given hyporesponsive sensory systems, and thus reduced interference. Here, using artificial patterns of olfactory bulb stimulation in a fear conditioning procedure in the rat, we tested the effects of imposed post-training replay during SWS and waking on strength and precision of pattern memory. The results show that imposed replay during post-training SWS enhanced the subsequent strength of memory, whereas the identical replay during waking induced extinction. The magnitude of this enhancement was dependent on the timing of imposed replay relative to cortical sharp-waves. Imposed SWS replay of stimuli, which differed from the conditioned stimulus, did not affect conditioned stimulus memory strength but induced generalization of the fear memory to novel artificial patterns. Finally, post-training disruption of piriform cortex intracortical association fiber synapses, hypothesized to be critical for experience-dependent odor coding, also impaired subsequent memory precision but not strength. These results suggest that SWS replay in the olfactory cortex enhances memory consolidation, and that memory precision is dependent on the fidelity of that replay. PMID:24719093

Brain Region-Specific Activity Patterns after Recent or Remote Memory Retrieval of Auditory Conditioned Fear

ERIC Educational Resources Information Center

Kwon, Jeong-Tae; Jhang, Jinho; Kim, Hyung-Su; Lee, Sujin; Han, Jin-Hee

2012-01-01

Memory is thought to be sparsely encoded throughout multiple brain regions forming unique memory trace. Although evidence has established that the amygdala is a key brain site for memory storage and retrieval of auditory conditioned fear memory, it remains elusive whether the auditory brain regions may be involved in fear memory storage or…

Trace and Contextual Fear Conditioning Require Neural Activity and NMDA Receptor-Dependent Transmission in the Medial Prefrontal Cortex

ERIC Educational Resources Information Center

Gilmartin, Marieke R.; Helmstetter, Fred J.

2010-01-01

The contribution of the medial prefrontal cortex (mPFC) to the formation of memory is a subject of considerable recent interest. Notably, the mechanisms supporting memory acquisition in this structure are poorly understood. The mPFC has been implicated in the acquisition of trace fear conditioning, a task that requires the association of a…

The Less Things Change, the More They Are Different: Contributions of Long-Term Synaptic Plasticity and Homeostasis to Memory

ERIC Educational Resources Information Center

Schacher, Samuel; Hu, Jiang-Yuan

2014-01-01

An important cellular mechanism contributing to the strength and duration of memories is activity-dependent alterations in the strength of synaptic connections within the neural circuit encoding the memory. Reversal of the memory is typically correlated with a reversal of the cellular changes to levels expressed prior to the stimulation. Thus, for…

Surface expression of NMDA receptor changes during memory consolidation in the crab Neohelice granulata

PubMed Central

Hepp, Yanil; Salles, Angeles; Carbo-Tano, Martin

2016-01-01

The aim of the present study was to analyze the surface expression of the NMDA-like receptors during the consolidation of contextual learning in the crab Neohelice granulata. Memory storage is based on alterations in the strength of synaptic connections between neurons. The glutamatergic synapses undergo various forms of N-methyl-D aspartate receptor (NMDAR)-dependent changes in strength, a process that affects the abundance of other receptors at the synapse and underlies some forms of learning and memory. Here we propose a direct regulation of the NMDAR. Changes in NMDAR's functionality might be induced by the modification of the subunit's expression or cellular trafficking. This trafficking does not only include NMDAR's movement between synaptic and extra-synaptic localizations but also the cycling between intracellular compartments and the plasma membrane, a process called surface expression. Consolidation of contextual learning affects the surface expression of the receptor without affecting its general expression. The surface expression of the GluN1 subunit of the NMDAR is down-regulated immediately after training, up-regulated 3 h after training and returns to naïve and control levels 24 h after training. The changes in NMDAR surface expression observed in the central brain are not seen in the thoracic ganglion. A similar increment in surface expression of GluN1 in the central brain is observed 3 h after administration of the competitive GABAA receptor antagonist, bicuculline. These consolidation changes are part of a plasticity event that first, during the down-regulation, stabilizes the trace and later, at 3-h post-training, changes the threshold for synapse activation. PMID:27421895

Does exercise habit strength moderate the relationship between emotional distress and short-term memory in Malaysian primary school children?

PubMed

Zainol, Nurul Ain; Hashim, Hairul Anuar

2015-01-01

We examined the moderating effects of exercise habit strength on the relationship between emotional distress and short-term memory in primary school children. The sample consisted of 165 primary school students (10-12 years old). Participants completed measures of emotional distress, exercise habit strength, and the Digit Span Test. Mid-year exam results were used as an indicator of academic performance. Structural equation modelling (SEM) was used to analyse the data. The results of SEM revealed an acceptable fit for the hypothesised model. Exercise habit was positively associated with short-term memory, and better short-term memory was associated with better academic performance. However, although an inverse relationship was found between emotional distress and short-term memory, a positive association was found between exercise habit strength and emotional distress. The findings indicate that exercise habit is positively associated with cognitive ability and mediates the negative effect of distress.

An Attention-Sensitive Memory Trace in Macaque MT Following Saccadic Eye Movements

PubMed Central

Yao, Tao; Treue, Stefan; Krishna, B. Suresh

2016-01-01

We experience a visually stable world despite frequent retinal image displacements induced by eye, head, and body movements. The neural mechanisms underlying this remain unclear. One mechanism that may contribute is transsaccadic remapping, in which the responses of some neurons in various attentional, oculomotor, and visual brain areas appear to anticipate the consequences of saccades. The functional role of transsaccadic remapping is actively debated, and many of its key properties remain unknown. Here, recording from two monkeys trained to make a saccade while directing attention to one of two spatial locations, we show that neurons in the middle temporal area (MT), a key locus in the motion-processing pathway of humans and macaques, show a form of transsaccadic remapping called a memory trace. The memory trace in MT neurons is enhanced by the allocation of top-down spatial attention. Our data provide the first demonstration, to our knowledge, of the influence of top-down attention on the memory trace anywhere in the brain. We find evidence only for a small and transient effect of motion direction on the memory trace (and in only one of two monkeys), arguing against a role for MT in the theoretically critical yet empirically contentious phenomenon of spatiotopic feature-comparison and adaptation transfer across saccades. Our data support the hypothesis that transsaccadic remapping represents the shift of attentional pointers in a retinotopic map, so that relevant locations can be tracked and rapidly processed across saccades. Our results resolve important issues concerning the perisaccadic representation of visual stimuli in the dorsal stream and demonstrate a significant role for top-down attention in modulating this representation. PMID:26901857

Time Constraints and Resource Sharing in Adults' Working Memory Spans

ERIC Educational Resources Information Center

Barrouillet, Pierre; Bernardin, Sophie; Camos, Valerie

2004-01-01

This article presents a new model that accounts for working memory spans in adults, the time-based resource-sharing model. The model assumes that both components (i.e., processing and maintenance) of the main working memory tasks require attention and that memory traces decay as soon as attention is switched away. Because memory retrievals are…

Post-event spontaneous intrusive recollections and strength of memory for emotional events in men and women.

PubMed

Ferree, Nikole K; Cahill, Larry

2009-03-01

Spontaneous intrusive recollections (SIRs) follow traumatic events in clinical and non-clinical populations. To determine whether any relationship exists between SIRs and enhanced memory for emotional events, participants viewed emotional or neutral films, had their memory for the films tested two days later, and estimated the number of SIRs they experienced for each film. SIR frequency related positively to memory strength, an effect more pronounced in the emotional condition. These findings represent the first demonstration of a relationship between SIRs occurring after an emotional experience and subsequent memory strength for that experience. The results are consistent with the possibility that emotional arousal leads both to elevated SIR frequency and better memory, and that the covert rehearsal associated with SIRs enhances memory for emotional relative to neutral stimuli. Additional evidence of menstrual cycle influences on SIR incidence in female participants appears to merit consideration in future work.

Post-event spontaneous intrusive recollections and strength of memory for emotional events in men and women

PubMed Central

Ferree, Nikole K.; Cahill, Larry

2009-01-01

Spontaneous intrusive recollections (SIRs) follow traumatic events in clinical and non-clinical populations. To determine whether any relationship exists between SIRs and enhanced memory for emotional events, participants viewed emotional or neutral films, had their memory for the films tested two days later, and estimated the number of SIRs they experienced for each film. SIR frequency related positively to memory strength, an effect more pronounced in the emotional condition. These findings represent the first demonstration of a relationship between SIRs occurring after an emotional experience and subsequent memory strength for that experience. The results are consistent with the possibility that emotional arousal leads both to elevated SIR frequency and better memory, and that the covert rehearsal associated with SIRs enhances memory for emotional relative to neutral stimuli. Additional evidence of menstrual cycle influences on SIR incidence in female participants appears to merit consideration in future work. PMID:19131257

[Interactions between the hippocampus and the amygdala in synaptic plasticity processes. A key to understanding the relations between motivation and memory].

PubMed

Almaguer-Melián, W; Bergado-Rosado, J A

Memory is initially stored as a transitory change that can become consolidated and converted into a long term memory trace. Consolidation largely depends on the emotional state. It is known that the hippocampus plays a role in the consolidation process of certain types of memory and that the amygdala might modulate the consolidation of the memory traces in other parts of the brain. The interaction between these two structures is crucial in many forms of learning and memory. The hippocampus, as well as the amygdala, display a type of synaptic plasticity known as long term potentiation (LTP), which is considered to be a cellular memory mechanism. Recently, it has been reported that the consolidation of the hippocampal LTP may be modulated, like memory, by the emotional state and by the activation of the basolateral amygdala. These findings, taken as a whole, can help to explain how the processes of consolidation of memory take place. At the same time they also constitute a more physiological model of the learning and memory processes, which will provide us with a more accurate understanding of the mechanisms behind the consolidation of the memory.

Memory Profiles in Children with Mild Intellectual Disabilities: Strengths and Weaknesses

ERIC Educational Resources Information Center

Van der Molen, Mariet J.; Van Luit, Johannes E. H.; Jongmans, Marian J.; Van der Molen, Maurits W.

2009-01-01

Strengths and weaknesses in short-term memory (STM) and working memory (WM) were identified in children with mild intellectual disabilities (MID) by comparing their performance to typically developing children matched on chronological age (CA children) and to younger typically developing children with similar mental capacities (MA children).…

Examining the Causes of Memory Strength Variability: Recollection, Attention Failure, or Encoding Variability?

ERIC Educational Resources Information Center

Koen, Joshua D.; Aly, Mariam; Wang, Wei-Chun; Yonelinas, Andrew P.

2013-01-01

A prominent finding in recognition memory is that studied items are associated with more variability in memory strength than new items. Here, we test 3 competing theories for why this occurs--the "encoding variability," "attention failure", and "recollection" accounts. Distinguishing among these theories is critical…

The Representation of Knowledge in Image Understanding.

DTIC Science & Technology

1985-03-01

for memory traces? It’s been quite a few years since Lashley wrote his famous paper "Search for the Engram ." That paper pinpointed the fundamental...34 engram hunters," mostly empirical neurobiologists guided by their own often powerful working hypotheses, ensued and has continued that search with...progress. What is an Engram ? (Some Informal Considerations) Memory, viewed as traces of experience, is necessarily massively . distributed. As an example

Time-Based Loss in Visual Short-Term Memory is from Trace Decay, not Temporal Distinctiveness

PubMed Central

Ricker, Timothy J.; Spiegel, Lauren R.; Cowan, Nelson

2014-01-01

There is no consensus as to why forgetting occurs in short-term memory tasks. In past work, we have shown that forgetting occurs with the passage of time, but there are two classes of theories that can explain this effect. In the present work, we investigate the reason for time-based forgetting by contrasting the predictions of temporal distinctiveness and trace decay in the procedure in which we have observed such loss, involving memory for arrays of characters or letters across several seconds. The first theory, temporal distinctiveness, predicts that increasing the amount of time between trials will lead to less proactive interference, resulting in less forgetting across a retention interval. In the second theory, trace decay, temporal distinctiveness between trials is irrelevant to the loss over a retention interval. Using visual array change detection tasks in four experiments, we find small proactive interference effects on performance under some specific conditions, but no concomitant change in the effect of a retention interval. We conclude that trace decay is the more suitable class of explanations of the time-based forgetting in short-term memory that we have observed, and we suggest the need for further clarity in what the exact basis of that decay may be. PMID:24884646

A New Stochastic Approach to Predict Peak and Residual Shear Strength of Natural Rock Discontinuities

NASA Astrophysics Data System (ADS)

Casagrande, D.; Buzzi, O.; Giacomini, A.; Lambert, C.; Fenton, G.

2018-01-01

Natural discontinuities are known to play a key role in the stability of rock masses. However, it is a non-trivial task to estimate the shear strength of large discontinuities. Because of the inherent complexity to access to the full surface of the large in situ discontinuities, researchers or engineers tend to work on small-scale specimens. As a consequence, the results are often plagued by the well-known scale effect. A new approach is here proposed to predict shear strength of discontinuities. This approach has the potential to avoid the scale effect. The rationale of the approach is as follows: a major parameter that governs the shear strength of a discontinuity within a rock mass is roughness, which can be accounted for by surveying the discontinuity surface. However, this is typically not possible for discontinuities contained within the rock mass where only traces are visible. For natural surfaces, it can be assumed that traces are, to some extent, representative of the surface. It is here proposed to use the available 2D information (from a visible trace, referred to as a seed trace) and a random field model to create a large number of synthetic surfaces (3D data sets). The shear strength of each synthetic surface can then be estimated using a semi-analytical model. By using a large number of synthetic surfaces and a Monte Carlo strategy, a meaningful shear strength distribution can be obtained. This paper presents the validation of the semi-analytical mechanistic model required to support the new approach for prediction of discontinuity shear strength. The model can predict both peak and residual shear strength. The second part of the paper lays the foundation of a random field model to support the creation of synthetic surfaces having statistical properties in line with those of the data of the seed trace. The paper concludes that it is possible to obtain a reasonable estimate of peak and residual shear strength of the discontinuities tested from the information from a single trace, without having access to the whole surface.

The Neurobiology of Learning and Memory.

ERIC Educational Resources Information Center

Thompson, Rihard F.

1986-01-01

Describes recent research findings in the area of neurobiology and its relationship to learning and memory. The article provides definitions of associative and nonassociative learning, identifies essential memory trace circuits of the mammalian brain, and discusses some neural mechanisms of learning. (TW)

Coding of Stimuli by Animals: Retrospection, Prospection, Episodic Memory and Future Planning

ERIC Educational Resources Information Center

Zentall, Thomas R.

2010-01-01

When animals code stimuli for later retrieval they can either code them in terms of the stimulus presented (as a retrospective memory) or in terms of the response or outcome anticipated (as a prospective memory). Although retrospective memory is typically assumed (as in the form of a memory trace), evidence of prospective coding has been found…

Recognition memory strength is predicted by pupillary responses at encoding while fixation patterns distinguish recollection from familiarity.

PubMed

Kafkas, Alexandros; Montaldi, Daniela

2011-10-01

Thirty-five healthy participants incidentally encoded a set of man-made and natural object pictures, while their pupil response and eye movements were recorded. At retrieval, studied and new stimuli were rated as novel, familiar (strong, moderate, or weak), or recollected. We found that both pupil response and fixation patterns at encoding predict later recognition memory strength. The extent of pupillary response accompanying incidental encoding was found to be predictive of subsequent memory. In addition, the number of fixations was also predictive of later recognition memory strength, suggesting that the accumulation of greater visual detail, even for single objects, is critical for the creation of a strong memory. Moreover, fixation patterns at encoding distinguished between recollection and familiarity at retrieval, with more dispersed fixations predicting familiarity and more clustered fixations predicting recollection. These data reveal close links between the autonomic control of pupil responses and eye movement patterns on the one hand and memory encoding on the other. Moreover, the data illustrate quantitative as well as qualitative differences in the incidental visual processing of stimuli, which are differentially predictive of the strength and the kind of memory experienced at recognition.

Forgetting, Reminding, and Remembering: The Retrieval of Lost Spatial Memory

PubMed Central

Morris, Richard G. M

2004-01-01

Retrograde amnesia can occur after brain damage because this disrupts sites of storage, interrupts memory consolidation, or interferes with memory retrieval. While the retrieval failure account has been considered in several animal studies, recent work has focused mainly on memory consolidation, and the neural mechanisms responsible for reactivating memory from stored traces remain poorly understood. We now describe a new retrieval phenomenon in which rats' memory for a spatial location in a watermaze was first weakened by partial lesions of the hippocampus to a level at which it could not be detected. The animals were then reminded by the provision of incomplete and potentially misleading information—an escape platform in a novel location. Paradoxically, both incorrect and correct place information reactivated dormant memory traces equally, such that the previously trained spatial memory was now expressed. It was also established that the reminding procedure could not itself generate new learning in either the original environment, or in a new training situation. The key finding is the development of a protocol that definitively distinguishes reminding from new place learning and thereby reveals that a failure of memory during watermaze testing can arise, at least in part, from a disruption of memory retrieval. PMID:15314651

Influence of Response Prepotency Strength, General Working Memory Resources, and Specific Working Memory Load on the Ability to Inhibit Predominant Responses: A Comparison of Young and Elderly Participants

ERIC Educational Resources Information Center

Grandjean, Julien; Collette, Fabienne

2011-01-01

One conception of inhibitory functioning suggests that the ability to successfully inhibit a predominant response depends mainly on the strength of that response, the general functioning of working memory processes, and the working memory demand of the task (Roberts, Hager, & Heron, 1994). The proposal that inhibition and functional working memory…

Outlines of a multiple trace theory of temporal preparation.

PubMed

Los, Sander A; Kruijne, Wouter; Meeter, Martijn

2014-01-01

We outline a new multiple trace theory of temporal preparation (MTP), which accounts for behavior in reaction time (RT) tasks in which the participant is presented with a warning stimulus (S1) followed by a target stimulus (S2) that requires a speeded response. The theory assumes that during the foreperiod (FP; the S1-S2 interval) inhibition is applied to prevent premature response, while a wave of activation occurs upon the presentation of S2. On each trial, these actions are stored in a separate memory trace, which, jointly with earlier formed memory traces, starts contributing to preparation on subsequent trials. We show that MTP accounts for classic effects in temporal preparation, including mean RT-FP functions observed under a variety of FP distributions and asymmetric sequential effects. We discuss the advantages of MTP over other accounts of these effects (trace-conditioning and hazard-based explanations) and suggest a critical experiment to empirically distinguish among them.

A Simplified Conjoint Recognition Paradigm for the Measurement of Gist and Verbatim Memory

ERIC Educational Resources Information Center

Stahl, Christoph; Klauer, Karl Christoph

2008-01-01

The distinction between verbatim and gist memory traces has furthered the understanding of numerous phenomena in various fields, such as false memory research, research on reasoning and decision making, and cognitive development. To measure verbatim and gist memory empirically, an experimental paradigm and multinomial measurement model has been…

Level of Processing Modulates the Neural Correlates of Emotional Memory Formation

ERIC Educational Resources Information Center

Ritchey, Maureen; LaBar, Kevin S.; Cabeza, Roberto

2011-01-01

Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study used a levels-of-processing manipulation to characterize the impact of emotion on…

Memory Indexing: A Novel Method for Tracing Memory Processes in Complex Cognitive Tasks

ERIC Educational Resources Information Center

Renkewitz, Frank; Jahn, Georg

2012-01-01

We validate an eye-tracking method applicable for studying memory processes in complex cognitive tasks. The method is tested with a task on probabilistic inferences from memory. It provides valuable data on the time course of processing, thus clarifying previous results on heuristic probabilistic inference. Participants learned cue values of…

An information capacity limitation of visual short-term memory.

PubMed

Sewell, David K; Lilburn, Simon D; Smith, Philip L

2014-12-01

Research suggests that visual short-term memory (VSTM) has both an item capacity, of around 4 items, and an information capacity. We characterize the information capacity limits of VSTM using a task in which observers discriminated the orientation of a single probed item in displays consisting of 1, 2, 3, or 4 orthogonally oriented Gabor patch stimuli that were presented in noise for 50 ms, 100 ms, 150 ms, or 200 ms. The observed capacity limitations are well described by a sample-size model, which predicts invariance of ∑(i)(d'(i))² for displays of different sizes and linearity of (d'(i))² for displays of different durations. Performance was the same for simultaneous and sequentially presented displays, which implicates VSTM as the locus of the observed invariance and rules out explanations that ascribe it to divided attention or stimulus encoding. The invariance of ∑(i)(d'(i))² is predicted by the competitive interaction theory of Smith and Sewell (2013), which attributes it to the normalization of VSTM traces strengths arising from competition among stimuli entering VSTM. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Long-term depression at the mossy fiber-deep cerebellar nucleus synapse.

PubMed

Zhang, Wei; Linden, David J

2006-06-28

Several lines of evidence have indicated that the deep cerebellar nuclei (DCN) are a site of memory storage for certain forms of motor learning, most notably associative eyelid conditioning. In particular, these experiments, together with network models, have implicated the excitatory glutamatergic synapse between mossy fibers and DCN neurons in this memory trace. However, to date, evidence for persistent use-dependent change in the strength of this synapse has been almost entirely absent. Here, we report that high-frequency burst stimulation of mossy fibers, either alone or paired with postsynaptic depolarization, gives rise to long-term depression (LTD) of the mossy fiber-DCN synapse. This form of LTD is not associated with changes in the paired-pulse ratio and is blocked by loading with a postsynaptic Ca2+ chelator but not by bath application of an NMDA receptor antagonist. Mossy fiber-DCN LTD requires activation of a group I metabotropic glutamate receptor (mGluR) and protein translation. Unlike mGluR/translation-dependent LTD in other brain regions, this form of LTD requires mGluR1 and is mGluR5 independent.

The Effect of Time on Word Learning: An Examination of Decay of the Memory Trace and Vocal Rehearsal in Children with and without Specific Language Impairment

ERIC Educational Resources Information Center

Alt, Mary; Spaulding, Tammie

2011-01-01

Purpose: The purpose of this study was to measure the effect of time to response in a fast-mapping word learning task for children with specific language impairment (SLI) and children with typically developing language skills (TD). Manipulating time to response allows us to examine decay of the memory trace, the use of vocal rehearsal, and their…

Fear Conditioning Effects on Sensitivity to Drug Reward

DTIC Science & Technology

2010-06-01

lasting potentiation of cocaine seeking after withdrawal. J Neurosci. 24(7): 1604-11. Martinowich K, Hattori D, Wu H, Fouse S, He F, Hu Y, Fan G...the CS has activated the memory trace. At this time point, the treatment can potentially modify the memory trace directly and alter the CS-CR bond...organism to anticipate and prepare for potentially dangerous conditions (Maren, 2005). Fear conditioning is one of the central features of

Memory consolidation by replay of stimulus-specific neural activity.

PubMed

Deuker, Lorena; Olligs, Jan; Fell, Juergen; Kranz, Thorsten A; Mormann, Florian; Montag, Christian; Reuter, Martin; Elger, Christian E; Axmacher, Nikolai

2013-12-04

Memory consolidation transforms initially labile memory traces into more stable representations. One putative mechanism for consolidation is the reactivation of memory traces after their initial encoding during subsequent sleep or waking state. However, it is still unknown whether consolidation of individual memory contents relies on reactivation of stimulus-specific neural representations in humans. Investigating stimulus-specific representations in humans is particularly difficult, but potentially feasible using multivariate pattern classification analysis (MVPA). Here, we show in healthy human participants that stimulus-specific activation patterns can indeed be identified with MVPA, that these patterns reoccur spontaneously during postlearning resting periods and sleep, and that the frequency of reactivation predicts subsequent memory for individual items. We conducted a paired-associate learning task with items and spatial positions and extracted stimulus-specific activity patterns by MVPA in a simultaneous electroencephalography and functional magnetic resonance imaging (fMRI) study. As a first step, we investigated the amount of fMRI volumes during rest that resembled either one of the items shown before or one of the items shown as a control after the resting period. Reactivations during both awake resting state and sleep predicted subsequent memory. These data are first evidence that spontaneous reactivation of stimulus-specific activity patterns during resting state can be investigated using MVPA. They show that reactivation occurs in humans and is behaviorally relevant for stabilizing memory traces against interference. They move beyond previous studies because replay was investigated on the level of individual stimuli and because reactivations were not evoked by sensory cues but occurred spontaneously.

The Electrophysiological Signature of Remember-Know Is Confounded with Memory Strength and Cannot Be Interpreted as Evidence for Dual-process Theory of Recognition.

PubMed

Brezis, Noam; Bronfman, Zohar Z; Yovel, Galit; Goshen-Gottstein, Yonatan

2017-02-01

The quantity and nature of the processes underlying recognition memory remains an open question. A majority of behavioral, neuropsychological, and brain studies have suggested that recognition memory is supported by two dissociable processes: recollection and familiarity. It has been conversely argued, however, that recollection and familiarity map onto a single continuum of mnemonic strength and hence that recognition memory is mediated by a single process. Previous electrophysiological studies found marked dissociations between recollection and familiarity, which have been widely held as corroborating the dual-process account. However, it remains unknown whether a strength interpretation can likewise apply for these findings. Here we describe an ERP study, using a modified remember-know (RK) procedure, which allowed us to control for mnemonic strength. We find that ERPs of high and low mnemonic strength mimicked the electrophysiological distinction between R and K responses, in a lateral positive component (LPC), 500-1000 msec poststimulus onset. Critically, when contrasting strength with RK experience, by comparing weak R to strong K responses, the electrophysiological signal mapped onto strength, not onto subjective RK experience. Invoking the LPC as support for dual-process accounts may, therefore, be amiss.

Neuromodulation: acetylcholine and memory consolidation.

PubMed

Hasselmo

1999-09-01

Clinical and experimental evidence suggests that hippocampal damage causes more severe disruption of episodic memories if those memories were encoded in the recent rather than the more distant past. This decrease in sensitivity to damage over time might reflect the formation of multiple traces within the hippocampus itself, or the formation of additional associative links in entorhinal and association cortices. Physiological evidence also supports a two-stage model of the encoding process in which the initial encoding occurs during active waking and deeper consolidation occurs via the formation of additional memory traces during quiet waking or slow-wave sleep. In this article I will describe the changes in cholinergic tone within the hippocampus in different stages of the sleep-wake cycle and will propose that these changes modulate different stages of memory formation. In particular, I will suggest that the high levels of acetylcholine that are present during active waking might set the appropriate dynamics for encoding new information in the hippocampus, by partially suppressing excitatory feedback connections and so facilitating encoding without interference from previously stored information. By contrast, the lower levels of acetylcholine that are present during quiet waking and slow-wave sleep might release this suppression and thereby allow a stronger spread of activity within the hippocampus itself and from the hippocampus to the entorhinal cortex, thus facilitating the process of consolidation of separate memory traces.

The construction of meaning.

PubMed

Kintsch, Walter; Mangalath, Praful

2011-04-01

We argue that word meanings are not stored in a mental lexicon but are generated in the context of working memory from long-term memory traces that record our experience with words. Current statistical models of semantics, such as latent semantic analysis and the Topic model, describe what is stored in long-term memory. The CI-2 model describes how this information is used to construct sentence meanings. This model is a dual-memory model, in that it distinguishes between a gist level and an explicit level. It also incorporates syntactic information about how words are used, derived from dependency grammar. The construction of meaning is conceptualized as feature sampling from the explicit memory traces, with the constraint that the sampling must be contextually relevant both semantically and syntactically. Semantic relevance is achieved by sampling topically relevant features; local syntactic constraints as expressed by dependency relations ensure syntactic relevance. Copyright © 2010 Cognitive Science Society, Inc.

The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation.

PubMed

Miyamoto, Daisuke; Hirai, Daichi; Murayama, Masanori

2017-01-01

Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5-4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation. During slow wave sleep, inter-areal interactions between the cortex and hippocampus (HC) have been proposed to consolidate declarative memory; however, interactions for non-declarative (HC-independent) memory remain largely uninvestigated. We recently showed that the directional influence in a slow-wave range through a top-down cortical long-range circuit is involved in the consolidation of non-declarative memory. At the synaptic level, the average cortical synaptic strength is known to be potentiated during wakefulness and depressed during sleep. Moreover, learning causes plasticity in a subset of synapses, allocating memory to them. Sleep may help to differentiate synaptic strength between allocated and non-allocated synapses (i.e., improving the signal-to-noise ratio, which may facilitate memory consolidation). Herein, we offer perspectives on inter-areal interactions and synaptic plasticity for memory consolidation during sleep.

The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation

PubMed Central

Miyamoto, Daisuke; Hirai, Daichi; Murayama, Masanori

2017-01-01

Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5–4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation. During slow wave sleep, inter-areal interactions between the cortex and hippocampus (HC) have been proposed to consolidate declarative memory; however, interactions for non-declarative (HC-independent) memory remain largely uninvestigated. We recently showed that the directional influence in a slow-wave range through a top-down cortical long-range circuit is involved in the consolidation of non-declarative memory. At the synaptic level, the average cortical synaptic strength is known to be potentiated during wakefulness and depressed during sleep. Moreover, learning causes plasticity in a subset of synapses, allocating memory to them. Sleep may help to differentiate synaptic strength between allocated and non-allocated synapses (i.e., improving the signal-to-noise ratio, which may facilitate memory consolidation). Herein, we offer perspectives on inter-areal interactions and synaptic plasticity for memory consolidation during sleep. PMID:29213231

Neural Similarity Between Encoding and Retrieval is Related to Memory Via Hippocampal Interactions

PubMed Central

Ritchey, Maureen; Wing, Erik A.; LaBar, Kevin S.; Cabeza, Roberto

2013-01-01

A fundamental principle in memory research is that memory is a function of the similarity between encoding and retrieval operations. Consistent with this principle, many neurobiological models of declarative memory assume that memory traces are stored in cortical regions, and the hippocampus facilitates the reactivation of these traces during retrieval. The present investigation tested the novel prediction that encoding–retrieval similarity can be observed and related to memory at the level of individual items. Multivariate representational similarity analysis was applied to functional magnetic resonance imaging data collected during encoding and retrieval of emotional and neutral scenes. Memory success tracked fluctuations in encoding–retrieval similarity across frontal and posterior cortices. Importantly, memory effects in posterior regions reflected increased similarity between item-specific representations during successful recognition. Mediation analyses revealed that the hippocampus mediated the link between cortical similarity and memory success, providing crucial evidence for hippocampal–cortical interactions during retrieval. Finally, because emotional arousal is known to modulate both perceptual and memory processes, similarity effects were compared for emotional and neutral scenes. Emotional arousal was associated with enhanced similarity between encoding and retrieval patterns. These findings speak to the promise of pattern similarity measures for evaluating memory representations and hippocampal–cortical interactions. PMID:22967731

Recollection Rejection: How Children Edit Their False Memories.

ERIC Educational Resources Information Center

Brainerd, C. J.; Reyna, V. F.

2002-01-01

Presents new measure of children's use of an editing operation that suppresses false memories by accessing verbatim traces of true events. Application of the methodology showed that false-memory editing increased dramatically between early and middle childhood. Measure reacted appropriately to experimental manipulations. Developmental reductions…

No Recovery of Memory When Cognitive Load Is Decreased

ERIC Educational Resources Information Center

Ricker, Timothy J.; Vergauwe, Evie; Hinrichs, Garrett A.; Blume, Christopher L.; Cowan, Nelson

2015-01-01

There is substantial debate in the field of short-term memory (STM) as to whether the process of active maintenance occurs through memory-trace reactivation or repair. A key difference between these 2 potential mechanisms is that a repair mechanism should lead to recovery of forgotten information. The ability to recover forgotten memories would be…

Protein Synthesis Underlies Post-Retrieval Memory Consolidation to a Restricted Degree Only when Updated Information Is Obtained

ERIC Educational Resources Information Center

Rodriguez-Ortiz, Carlos J.; De la Cruz, Vanesa; Gutierrez, Ranier; Bermudez-Rattoni, Federico

2005-01-01

Consolidation theory proposes that through the synthesis of new proteins recently acquired memories are strengthened over time into a stable long-term memory trace. However, evidence has accumulated suggesting that retrieved memory is susceptible to disruption, seeming to consolidate again (reconsolidate) to be retained in long-term storage. Here…

Effect of nitrogen on iron-manganese-based shape memory alloys

NASA Astrophysics Data System (ADS)

Ariapour, Azita

Shape memory effect is due to a reversible martensitic transformation. The major drawback in case of Fe-Mn-based shape memory alloys is their inferior shape memory effect compared to Ni-Ti and Cu-based shape memory alloys and their low strength and corrosion resistance compared to steel alloys. It is known that by increasing the alloy strength the shape memory effect can be improved. Nitrogen in solid solution can increase the strength of steels to a greater extent than other major alloying elements. However, its effect on shape memory effect of Fe-Mn-based alloys is ambiguous. In this work first we investigated the effect of nitrogen addition in solid solution on both shape memory effect (SME) and strength of a Fe-Mn-Cr-Ni-Si shape memory alloy (SMA). It was found that interstitial nitrogen suppressed the shape memory effect in these alloys. As an example addition of 0.24 wt % nitrogen in solid solution to the alloy system suppressed the SME by ˜80% and increased the strength by 20%. A reduction of martensitic phase formation was found to be the dominant factor in suppression of the SME. This was related, experimentally and theoretically to stacking fault energy of the alloy as well as the driving force and friction force during the transformation. The second approach was doping the alloy with both 0.36 wt% of nitrogen and 0.36 wt% of niobium. Niobium has great affinity for nitrogen and thus NbN dispersed particles can be produced in the alloy following hot rolling. Then particles prevent growth of the alloy and increase the strength of the alloy due to reduced grain size, and precipitation hardening. The improvement of SME in this alloy compared to the interstitial containing alloys was due to the large removal of the nitrogen from solid solution. In case of all the alloys studied in this work, the presence of nitrogen in solid solution improved the corrosion resistance of the alloy. This suggests that nitrogen can replace nickel in the alloy. One of the proposed applications for high strength Fe-Mn-based alloys is as tendon rods in prestressed concrete. The advantage of M alloys in this application is the possibility of producing curved structural prestressed concrete.

The attentional blink reveals serial working memory encoding: evidence from virtual and human event-related potentials.

PubMed

Craston, Patrick; Wyble, Brad; Chennu, Srivas; Bowman, Howard

2009-03-01

Observers often miss a second target (T2) if it follows an identified first target item (T1) within half a second in rapid serial visual presentation (RSVP), a finding termed the attentional blink. If two targets are presented in immediate succession, however, accuracy is excellent (Lag 1 sparing). The resource sharing hypothesis proposes a dynamic distribution of resources over a time span of up to 600 msec during the attentional blink. In contrast, the ST(2) model argues that working memory encoding is serial during the attentional blink and that, due to joint consolidation, Lag 1 is the only case where resources are shared. Experiment 1 investigates the P3 ERP component evoked by targets in RSVP. The results suggest that, in this context, P3 amplitude is an indication of bottom-up strength rather than a measure of cognitive resource allocation. Experiment 2, employing a two-target paradigm, suggests that T1 consolidation is not affected by the presentation of T2 during the attentional blink. However, if targets are presented in immediate succession (Lag 1 sparing), they are jointly encoded into working memory. We use the ST(2) model's neural network implementation, which replicates a range of behavioral results related to the attentional blink, to generate "virtual ERPs" by summing across activation traces. We compare virtual to human ERPs and show how the results suggest a serial nature of working memory encoding as implied by the ST(2) model.

Changing constructions of machismo for Latino men in therapy: "the devil never sleeps".

PubMed

Falicov, Celia Jaes

2010-09-01

This paper presents current narratives about masculinity that question simplistic negative stereotypes of machismo for Latino heterosexual men. Various models of masculinity within Latino cultures are described using evidence from ethnographic studies, research data, and clinical observation. Therapeutic advantages of including positive cultural masculine traits such as respect and dignity are illustrated with an extensive case study. The case highlights contradictions in the coexistence of constructions of masculinity and traces progressive stages for transforming these constructions. In this strength-based approach, attention is directed to elements of cultural memory that reclaim a strong relational ethic present in the indigenous cultures. "Within the culture" definitions of masculinity contribute alternative constructions toward a more empowering cultural narrative for Latino men than the usual negative stereotypes. 2010 © FPI, Inc.

Decoding individual episodic memory traces in the human hippocampus.

PubMed

Chadwick, Martin J; Hassabis, Demis; Weiskopf, Nikolaus; Maguire, Eleanor A

2010-03-23

In recent years, multivariate pattern analyses have been performed on functional magnetic resonance imaging (fMRI) data, permitting prediction of mental states from local patterns of blood oxygen-level-dependent (BOLD) signal across voxels. We previously demonstrated that it is possible to predict the position of individuals in a virtual-reality environment from the pattern of activity across voxels in the hippocampus. Although this shows that spatial memories can be decoded, substantially more challenging, and arguably only possible to investigate in humans, is whether it is feasible to predict which complex everyday experience, or episodic memory, a person is recalling. Here we document for the first time that traces of individual rich episodic memories are detectable and distinguishable solely from the pattern of fMRI BOLD signals across voxels in the human hippocampus. In so doing, we uncovered a possible functional topography in the hippocampus, with preferential episodic processing by some hippocampal regions over others. Moreover, our results imply that the neuronal traces of episodic memories are stable (and thus predictable) even over many re-activations. Finally, our data provide further evidence for functional differentiation within the medial temporal lobe, in that we show the hippocampus contains significantly more episodic information than adjacent structures. 2010 Elsevier Ltd. All rights reserved.

Time-based loss in visual short-term memory is from trace decay, not temporal distinctiveness.

PubMed

Ricker, Timothy J; Spiegel, Lauren R; Cowan, Nelson

2014-11-01

There is no consensus as to why forgetting occurs in short-term memory tasks. In past work, we have shown that forgetting occurs with the passage of time, but there are 2 classes of theories that can explain this effect. In the present work, we investigate the reason for time-based forgetting by contrasting the predictions of temporal distinctiveness and trace decay in the procedure in which we have observed such loss, involving memory for arrays of characters or letters across several seconds. The 1st theory, temporal distinctiveness, predicts that increasing the amount of time between trials will lead to less proactive interference, resulting in less forgetting across a retention interval. In the 2nd theory, trace decay, temporal distinctiveness between trials is irrelevant to the loss over a retention interval. Using visual array change detection tasks in 4 experiments, we find small proactive interference effects on performance under some specific conditions, but no concomitant change in the effect of a retention interval. We conclude that trace decay is the more suitable class of explanations of the time-based forgetting in short-term memory that we have observed, and we suggest the need for further clarity in what the exact basis of that decay may be. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Properties and Potential of Two (ni,pt)ti Alloys for Use as High-temperature Actuator Materials

NASA Technical Reports Server (NTRS)

Noebe, Ronald; Gaydosh, Darrell; Padula, Santo, II.; Garg, Anita; Biles, Tiffany; Nathal, Michael

2005-01-01

The microstructure, transformation temperatures, basic tensile properties, shape memory behavior, and work output for two (Ni,Ti)Pt high-temperature shape memory alloys have been characterized. One was a Ni30Pt20Ti50 alloy (referred to as 20Pt) with transformation temperatures above 230 C and the other was a Ni20Pt30Ti50 alloy (30Pt) with transformation temperatures about 530 C. Both materials displayed shape memory behavior and were capable of 100% (no-load) strain recovery for strain levels up to their fracture limit (3-4%) when deformed at room temperature. For the 20Pt alloy, the tensile strength, modulus, and ductility dramatically increased when the material was tested just about the austenite finish (A(sub f)) temperature. For the 30Pt alloy, a similar change in yield behavior at temperatures above the A(sub f) was not observed. In this case the strength of the austentite phase was at best comparable and generally much weaker than the martensite phase. A ductility minimum was also observed just below the A(sub s) temperature in this alloy. As a result of these differences in tensile behavior, the two alloys performed completely different when thermally cycled under constant load. The 20Pt alloy behaved similar to conventional binary NiTi alloys with work output due to the martensite-to-austenite transformation initially increasing with applied stress. The maximum work output measured in the 20Pt alloy was nearly 9 J/cu cm and was limited by the tensile ductility of the material. In contrast, the martensite-to-austenite transformation in the 30Pt alloy was not capable of performing work against any bias load. The reason for this behavior was traced back to its basic mechanical properties, where the yield strength of the austenite phase was similar to or lower than that of the martensite phase, depending on temperature. Hence, the recovery or transformation strain for the 30Pt alloy under load was essentially zero, resulting in zero work output.

Sex and spatial position effects on object location memory following intentional learning of object identities.

PubMed

Alexander, Gerianne M; Packard, Mark G; Peterson, Bradley S

2002-01-01

Memory for object location relative both to veridical center (left versus right visual hemispace) and to eccentricity (central versus peripheral objects) was measured in 26 males and 25 females using the Silverman and Eals Location Memory Task. A subset of participants (17 males and 13 females) also completed a measure of implicit learning, the mirror-tracing task. No sex differences were observed in memory for object identities. Further, in both sexes, memory for object locations was better for peripherally located objects than for centrally located objects. In contrast to these similarities in female and male task performance, females but not males showed better recovery of object locations in the right compared to the left visual hemispace. Moreover, memory for object locations in the right hemispace was associated with mirror-tracing performance in women but not in men. Together, these data suggest that the processing of object features and object identification in the left cerebral hemisphere may include processing of spatial information that may contribute to superior object location memory in females relative to males.

Targeted Memory Reactivation during Sleep Adaptively Promotes the Strengthening or Weakening of Overlapping Memories.

PubMed

Oyarzún, Javiera P; Morís, Joaquín; Luque, David; de Diego-Balaguer, Ruth; Fuentemilla, Lluís

2017-08-09

System memory consolidation is conceptualized as an active process whereby newly encoded memory representations are strengthened through selective memory reactivation during sleep. However, our learning experience is highly overlapping in content (i.e., shares common elements), and memories of these events are organized in an intricate network of overlapping associated events. It remains to be explored whether and how selective memory reactivation during sleep has an impact on these overlapping memories acquired during awake time. Here, we test in a group of adult women and men the prediction that selective memory reactivation during sleep entails the reactivation of associated events and that this may lead the brain to adaptively regulate whether these associated memories are strengthened or pruned from memory networks on the basis of their relative associative strength with the shared element. Our findings demonstrate the existence of efficient regulatory neural mechanisms governing how complex memory networks are shaped during sleep as a function of their associative memory strength. SIGNIFICANCE STATEMENT Numerous studies have demonstrated that system memory consolidation is an active, selective, and sleep-dependent process in which only subsets of new memories become stabilized through their reactivation. However, the learning experience is highly overlapping in content and thus events are encoded in an intricate network of related memories. It remains to be explored whether and how memory reactivation has an impact on overlapping memories acquired during awake time. Here, we show that sleep memory reactivation promotes strengthening and weakening of overlapping memories based on their associative memory strength. These results suggest the existence of an efficient regulatory neural mechanism that avoids the formation of cluttered memory representation of multiple events and promotes stabilization of complex memory networks. Copyright © 2017 the authors 0270-6474/17/377748-11$15.00/0.

Memory of myself: autobiographical memory and identity in Alzheimer's disease.

PubMed

Addis, Donna Rose; Tippett, Lynette J

2004-01-01

A number of theories posit a relationship between autobiographical memory and identity. To test this we assessed the status of autobiographical memory and identity in 20 individuals with Alzheimer's disease (AD) and 20 age-matched controls, and investigated whether degree of autobiographical memory impairment was associated with changes in identity. Two tests of autobiographical memory (Autobiographical Memory Interview, autobiographical fluency) and two measures of identity (Twenty Statements Test, identity items of the Tennessee Self Concept Scale) were administered. AD participants exhibited significant impairments on both memory tests, and changes in the strength, quality, and direction of identity relative to controls. Impairments of some components of autobiographical memory, particularly autobiographical memory for childhood and early adulthood, were related to changes in the strength and quality of identity. These findings support the critical role of early adulthood autobiographical memories (16-25 years) in identity, and suggest autobiographical memory loss affects identity.

Hippocampal activity during recognition memory co-varies with the accuracy and confidence of source memory judgments.

PubMed

Yu, Sarah S; Johnson, Jeffrey D; Rugg, Michael D

2012-06-01

It has been proposed that the hippocampus selectively supports retrieval of contextual associations, but an alternative view holds that the hippocampus supports strong memories regardless of whether they contain contextual information. We employed a memory test that combined the 'Remember/Know' and source memory procedures, which allowed test items to be segregated both by memory strength (recognition accuracy) and, separately, by the quality of the contextual information that could be retrieved (indexed by the accuracy/confidence of a source memory judgment). As measured by fMRI, retrieval-related hippocampal activity tracked the quality of retrieved contextual information and not memory strength. These findings are consistent with the proposal that the hippocampus supports contextual recollection rather than recognition memory more generally. Copyright © 2011 Wiley Periodicals, Inc.

Differentiation and Response Bias in Episodic Memory: Evidence from Reaction Time Distributions

ERIC Educational Resources Information Center

Criss, Amy H.

2010-01-01

In differentiation models, the processes of encoding and retrieval produce an increase in the distribution of memory strength for targets and a decrease in the distribution of memory strength for foils as the amount of encoding increases. This produces an increase in the hit rate and decrease in the false-alarm rate for a strongly encoded compared…

Impaired short-term memory for pitch in congenital amusia.

PubMed

Tillmann, Barbara; Lévêque, Yohana; Fornoni, Lesly; Albouy, Philippe; Caclin, Anne

2016-06-01

Congenital amusia is a neuro-developmental disorder of music perception and production. The hypothesis is that the musical deficits arise from altered pitch processing, with impairments in pitch discrimination (i.e., pitch change detection, pitch direction discrimination and identification) and short-term memory. The present review article focuses on the deficit of short-term memory for pitch. Overall, the data discussed here suggest impairments at each level of processing in short-term memory tasks; starting with the encoding of the pitch information and the creation of the adequate memory trace, the retention of the pitch traces over time as well as the recollection and comparison of the stored information with newly incoming information. These impairments have been related to altered brain responses in a distributed fronto-temporal network, associated with decreased connectivity between these structures, as well as in abnormalities in the connectivity between the two auditory cortices. In contrast, amusic participants׳ short-term memory abilities for verbal material are preserved. These findings show that short-term memory deficits in congenital amusia are specific to pitch, suggesting a pitch-memory system that is, at least partly, separated from verbal memory. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Semantic priming increases word frequency judgments: Evidence for the role of memory strength in frequency estimation.

PubMed

Woltz, Dan J; Gardner, Michael K

2015-09-01

Previous research has demonstrated a systematic, nonlinear relationship between word frequency judgments and values from word frequency norms. This relationship could reflect a perceptual process similar to that found in the psychophysics literature for a variety of sensory phenomena. Alternatively, it could reflect memory strength differences that are expected for words of varying levels of prior exposure. Two experiments tested the memory strength explanation by semantically priming words prior to frequency judgments. Exposure to related word meanings produced a small but measurable increase in target word frequency ratings. Repetition but not semantic priming had a greater impact on low compared to high frequency words. These findings are consistent with a memory strength view of frequency judgments that assumes a distributed network with lexical and semantic levels of representation. Copyright © 2015 Elsevier B.V. All rights reserved.

Virtual memory

NASA Technical Reports Server (NTRS)

Denning, P. J.

1986-01-01

Virtual memory was conceived as a way to automate overlaying of program segments. Modern computers have very large main memories, but need automatic solutions to the relocation and protection problems. Virtual memory serves this need as well and is thus useful in computers of all sizes. The history of the idea is traced, showing how it has become a widespread, little noticed feature of computers today.

Long-Term Memory for Instrumental Responses Does Not Undergo Protein Synthesis-Dependent Reconsolidation upon Retrieval

ERIC Educational Resources Information Center

Hernandez, Pepe J.; Kelley, Ann E.

2004-01-01

Recent evidence indicates that certain forms of memory, upon recall, may return to a labile state requiring the synthesis of new proteins in order to preserve or reconsolidate the original memory trace. While the initial consolidation of "instrumental memories" has been shown to require de novo protein synthesis in the nucleus accumbens, it is not…

The Failure of Memory: Reflections on Rhetoric and Public Remembrance

ERIC Educational Resources Information Center

Phillips, Kendall R.

2010-01-01

The rapid growth of public memory studies in the field of rhetoric suggests the need to reflect upon the ways in which the practices of rhetoric and the notion of memory intersect. In this essay, I trace the intersection between memory and rhetoric back to the works of Plato and Aristotle. These early works suggest that one reason for attending to…

Neural Evidence for a Distinction Between Short-Term Memory and the Focus of Attention

PubMed Central

Lewis-Peacock, Jarrod A.; Drysdale, Andrew T.; Oberauer, Klaus; Postle, Bradley R.

2011-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay-period activity may in fact reflect the focus of attention, rather than short-term memory. We unconfounded attention and memory by causing external and internal shifts of attention away from items that were being actively retained. Multivariate pattern analysis of fMRI indicated that only items within the focus of attention elicited an active neural trace. Activity corresponding to representations of items outside the focus quickly dropped to baseline. Nevertheless, this information was remembered after a brief delay. Our data also show that refocusing attention towards a previously unattended memory item can reactivate its neural signature. The loss of sustained activity has long been thought to indicate a disruption of short-term memory, but our results suggest that, even for small memory loads not exceeding the capacity limits of short-term memory, the active maintenance of a stimulus representation may not be necessary for its short-term retention. PMID:21955164

Temporally Graded Activation of Neocortical Regions in Response to Memories of Different Ages

PubMed Central

Woodard, John L.; Seidenberg, Michael; Nielson, Kristy A.; Miller, Sarah K.; Franczak, Malgorzata; Antuono, Piero; Douville, Kelli L.; Rao, Stephen M.

2007-01-01

The temporally graded memory impairment seen in many neurobehavioral disorders implies different neuroanatomical pathways and/or cognitive mechanisms involved in storage and retrieval of memories of different ages. A dynamic interaction between medial-temporal and neocortical brain regions has been proposed to account for memory’s greater permanence with time. Despite considerable debate concerning its time-dependent role in memory retrieval, medial-temporal lobe activity has been well studied. However, the relative participation of neocortical regions in recent and remote memory retrieval has received much less attention. Using functional magnetic resonance imaging, we demonstrate robust, temporally graded signal differences in posterior cingulate, right middle frontal, right fusiform, and left middle temporal regions in healthy older adults during famous name identification from two disparate time epochs. Importantly, no neocortical regions demonstrated greater response to older than to recent stimuli. Our results suggest a possible role of these neocortical regions in temporally dating items in memory and in establishing and maintaining memory traces throughout the lifespan. Theoretical implications of these findings for the two dominant models of remote memory functioning (Consolidation Theory and Multiple Trace Theory) are discussed. PMID:17583988

Repeated Stimulation of Cultured Networks of Rat Cortical Neurons Induces Parallel Memory Traces

ERIC Educational Resources Information Center

le Feber, Joost; Witteveen, Tim; van Veenendaal, Tamar M.; Dijkstra, Jelle

2015-01-01

During systems consolidation, memories are spontaneously replayed favoring information transfer from hippocampus to neocortex. However, at present no empirically supported mechanism to accomplish a transfer of memory from hippocampal to extra-hippocampal sites has been offered. We used cultured neuronal networks on multielectrode arrays and…

What’s the Gist? The influence of schemas on the neural correlates underlying true and false memories

PubMed Central

Webb, Christina E.; Turney, Indira C.; Dennis, Nancy A.

2017-01-01

The current study used a novel scene paradigm to investigate the role of encoding schemas on memory. Specifically, the study examined the influence of a strong encoding schema on retrieval of both schematic and non-schematic information, as well as false memories for information associated with the schema. Additionally, the separate roles of recollection and familiarity in both veridical and false memory retrieval were examined. The study identified several novel results. First, while many common neural regions mediated both schematic and non-schematic retrieval success, schematic recollection exhibited greater activation in visual cortex and hippocampus, regions commonly shown to mediate detailed retrieval. More effortful cognitive control regions in the prefrontal and parietal cortices, on the other hand, supported non-schematic recollection, while lateral temporal cortices supported familiarity-based retrieval of non-schematic items. Second, both true and false recollection, as well as familiarity, were mediated by activity in left middle temporal gyrus, a region associated with semantic processing and retrieval of schematic gist. Moreover, activity in this region was greater for both false recollection and false familiarity, suggesting a greater reliance on lateral temporal cortices for retrieval of illusory memories, irrespective of memory strength. Consistent with previous false memory studies, visual cortex showed increased activity for true compared to false recollection, suggesting that visual cortices are critical for distinguishing between previously viewed targets and related lures at retrieval. Additionally, the absence of common visual activity between true and false retrieval suggests that, unlike previous studies utilizing visual stimuli, when false memories are predicated on schematic gist and not perceptual overlap, there is little reliance on visual processes during false memory retrieval. Finally, the medial temporal lobe exhibited an interesting dissociation, showing greater activity for true compared to false recollection, as well as for false compared to true familiarity. These results provided an indication as to how different types of items are retrieved when studied within a highly schematic context. Results both replicate and extend previous true and false memory findings, supporting the Fuzzy Trace Theory. PMID:27697593

What's the gist? The influence of schemas on the neural correlates underlying true and false memories.

PubMed

Webb, Christina E; Turney, Indira C; Dennis, Nancy A

2016-12-01

The current study used a novel scene paradigm to investigate the role of encoding schemas on memory. Specifically, the study examined the influence of a strong encoding schema on retrieval of both schematic and non-schematic information, as well as false memories for information associated with the schema. Additionally, the separate roles of recollection and familiarity in both veridical and false memory retrieval were examined. The study identified several novel results. First, while many common neural regions mediated both schematic and non-schematic retrieval success, schematic recollection exhibited greater activation in visual cortex and hippocampus, regions commonly shown to mediate detailed retrieval. More effortful cognitive control regions in the prefrontal and parietal cortices, on the other hand, supported non-schematic recollection, while lateral temporal cortices supported familiarity-based retrieval of non-schematic items. Second, both true and false recollection, as well as familiarity, were mediated by activity in left middle temporal gyrus, a region associated with semantic processing and retrieval of schematic gist. Moreover, activity in this region was greater for both false recollection and false familiarity, suggesting a greater reliance on lateral temporal cortices for retrieval of illusory memories, irrespective of memory strength. Consistent with previous false memory studies, visual cortex showed increased activity for true compared to false recollection, suggesting that visual cortices are critical for distinguishing between previously viewed targets and related lures at retrieval. Additionally, the absence of common visual activity between true and false retrieval suggests that, unlike previous studies utilizing visual stimuli, when false memories are predicated on schematic gist and not perceptual overlap, there is little reliance on visual processes during false memory retrieval. Finally, the medial temporal lobe exhibited an interesting dissociation, showing greater activity for true compared to false recollection, as well as for false compared to true familiarity. These results provided an indication as to how different types of items are retrieved when studied within a highly schematic context. Results both replicate and extend previous true and false memory findings, supporting the Fuzzy Trace Theory. Copyright © 2016 Elsevier Ltd. All rights reserved.

Memory Variability Is Due to the Contribution of Recollection and Familiarity, Not to Encoding Variability

ERIC Educational Resources Information Center

Koen, Joshua D.; Yonelinas, Andrew P.

2010-01-01

It is well established that the memory strength of studied items is more variable than the strength of new items on tests of recognition memory, but the reason why this occurs is poorly understood. One account for this old "item variance effect" is based on single-process theory, which proposes that this effect is due to variability in how well…

A neural model of normal and abnormal learning and memory consolidation: adaptively timed conditioning, hippocampus, amnesia, neurotrophins, and consciousness.

PubMed

Franklin, Daniel J; Grossberg, Stephen

2017-02-01

How do the hippocampus and amygdala interact with thalamocortical systems to regulate cognitive and cognitive-emotional learning? Why do lesions of thalamus, amygdala, hippocampus, and cortex have differential effects depending on the phase of learning when they occur? In particular, why is the hippocampus typically needed for trace conditioning, but not delay conditioning, and what do the exceptions reveal? Why do amygdala lesions made before or immediately after training decelerate conditioning while those made later do not? Why do thalamic or sensory cortical lesions degrade trace conditioning more than delay conditioning? Why do hippocampal lesions during trace conditioning experiments degrade recent but not temporally remote learning? Why do orbitofrontal cortical lesions degrade temporally remote but not recent or post-lesion learning? How is temporally graded amnesia caused by ablation of prefrontal cortex after memory consolidation? How are attention and consciousness linked during conditioning? How do neurotrophins, notably brain-derived neurotrophic factor (BDNF), influence memory formation and consolidation? Is there a common output path for learned performance? A neural model proposes a unified answer to these questions that overcome problems of alternative memory models.

Time-Related Decay or Interference-Based Forgetting in Working Memory?

ERIC Educational Resources Information Center

Portrat, Sophie; Barrouillet, Pierre; Camos, Valerie

2008-01-01

The time-based resource-sharing model of working memory assumes that memory traces suffer from a time-related decay when attention is occupied by concurrent activities. Using complex continuous span tasks in which temporal parameters are carefully controlled, P. Barrouillet, S. Bernardin, S. Portrat, E. Vergauwe, & V. Camos (2007) recently…

Decoding Overlapping Memories in the Medial Temporal Lobes Using High-Resolution fMRI

ERIC Educational Resources Information Center

Chadwick, Martin J.; Hassabis, Demis; Maguire, Eleanor A.

2011-01-01

The hippocampus is proposed to process overlapping episodes as discrete memory traces, although direct evidence for this in human episodic memory is scarce. Using green-screen technology we created four highly overlapping movies of everyday events. Participants were scanned using high-resolution fMRI while recalling the movies. Multivariate…

Working Memory Span Development: A Time-Based Resource-Sharing Model Account

ERIC Educational Resources Information Center

Barrouillet, Pierre; Gavens, Nathalie; Vergauwe, Evie; Gaillard, Vinciane; Camos, Valerie

2009-01-01

The time-based resource-sharing model (P. Barrouillet, S. Bernardin, & V. Camos, 2004) assumes that during complex working memory span tasks, attention is frequently and surreptitiously switched from processing to reactivate decaying memory traces before their complete loss. Three experiments involving children from 5 to 14 years of age…

When Induction Meets Memory: Evidence for Gradual Transition from Similarity-Based to Category-Based Induction

ERIC Educational Resources Information Center

Fisher, Anna V.; Sloutsky, Vladimir M.

2005-01-01

The ability to perform induction appears early; however, underlying mechanisms remain unclear. Some argue that early induction is category based, whereas others suggest that early induction is similarity based. Category- and similarity-based induction should result in different memory traces and thus in different memory accuracy. Performing…

Attentional and non-attentional systems in the maintenance of verbal information in working memory: the executive and phonological loops

PubMed Central

Camos, Valérie; Barrouillet, Pierre

2014-01-01

Working memory is the structure devoted to the maintenance of information at short term during concurrent processing activities. In this respect, the question regarding the nature of the mechanisms and systems fulfilling this maintenance function is of particular importance and has received various responses in the recent past. In the time-based resource-sharing (TBRS) model, we suggest that only two systems sustain the maintenance of information at the short term, counteracting the deleterious effect of temporal decay and interference. A non-attentional mechanism of verbal rehearsal, similar to the one described by Baddeley in the phonological loop model, uses language processes to reactivate phonological memory traces. Besides this domain-specific mechanism, an executive loop allows the reconstruction of memory traces through an attention-based mechanism of refreshing. The present paper reviews evidence of the involvement of these two independent systems in the maintenance of verbal memory items. PMID:25426049

Extinguishing trace fear engages the retrosplenial cortex rather than the amygdala

PubMed Central

Kwapis, Janine L.; Jarome, Timothy J.; Lee, Jonathan L.; Gilmartin, Marieke R.; Helmstetter, Fred J.

2013-01-01

Extinction learning underlies the treatment for a variety of anxiety disorders. Most of what is known about the neurobiology of extinction is based on standard “delay” fear conditioning, in which awareness is not required for learning. Little is known about how complex, explicit associations extinguish, however. “Trace” conditioning is considered to be a rodent model of explicit fear because it relies on both the cortex and hippocampus and requires explicit contingency awareness in humans. Here, we explore the neural circuit supporting trace fear extinction in order to better understand how complex memories extinguish. We first show that the amygdala is selectively involved in delay fear extinction; blocking intra-amygdala glutamate receptors disrupted delay, but not trace extinction. Further, ERK phosphorylation was increased in the amygdala after delay, but not trace extinction. We then identify the retrosplenial cortex (RSC) as a key structure supporting trace extinction. ERK phosphorylation was selectively increased in the RSC following trace extinction and blocking intra-RSC NMDA receptors impaired trace, but not delay extinction. These findings indicate that delay and trace extinction require different neural circuits; delay extinction requires plasticity in the amygdala whereas trace extinction requires the RSC. Anxiety disorders linked to explicit memory may therefore depend on cortical processes that have not been traditionally targeted by extinction studies based on delay fear. PMID:24055593

Watching diagnoses develop: Eye movements reveal symptom processing during diagnostic reasoning.

PubMed

Scholz, Agnes; Krems, Josef F; Jahn, Georg

2017-10-01

Finding a probable explanation for observed symptoms is a highly complex task that draws on information retrieval from memory. Recent research suggests that observed symptoms are interpreted in a way that maximizes coherence for a single likely explanation. This becomes particularly clear if symptom sequences support more than one explanation. However, there are no existing process data available that allow coherence maximization to be traced in ambiguous diagnostic situations, where critical information has to be retrieved from memory. In this experiment, we applied memory indexing, an eye-tracking method that affords rich time-course information concerning memory-based cognitive processing during higher order thinking, to reveal symptom processing and the preferred interpretation of symptom sequences. Participants first learned information about causes and symptoms presented in spatial frames. Gaze allocation to emptied spatial frames during symptom processing and during the diagnostic response reflected the subjective status of hypotheses held in memory and the preferred interpretation of ambiguous symptoms. Memory indexing traced how the diagnostic decision developed and revealed instances of hypothesis change and biases in symptom processing. Memory indexing thus provided direct online evidence for coherence maximization in processing ambiguous information.

Pharmacogenetic reactivation of the original engram evokes an extinguished fear memory.

PubMed

Yoshii, Takahiro; Hosokawa, Hiroshi; Matsuo, Naoki

2017-02-01

Fear memory extinction has several characteristic behavioral features, such as spontaneous recovery, renewal, and reinstatement, suggesting that extinction training does not erase the original association between the conditioned stimulus (CS) and the unconditioned stimulus (US). However, it is unclear whether reactivation of the original physical record of memory (i.e., memory trace) is sufficient to produce conditioned fear response after extinction. Here, we performed pharmacogenetic neuronal activation using transgenic mice expressing hM3Dq DREADD (designer receptor exclusively activated by designer drug) under the control of the activity-dependent c-fos gene promoter. Neuronal ensembles activated during fear-conditioned learning were tagged with hM3Dq and subsequently reactivated after extinction training. The mice exhibited significant freezing, even when the fear memory was no longer triggered by external CS, indicating that the artificial reactivation of a specific neuronal ensemble was sufficient to evoke the extinguished fear response. This freezing was not observed in non-fear-conditioned mice expressing hM3dq in the same brain areas. These results directly demonstrated that at least part of the original fear memory trace remains after extinction, and such residual plasticity might reflect the persistent memory. Copyright © 2016 Elsevier Ltd. All rights reserved.

Circuit-Switched Memory Access in Photonic Interconnection Networks for High-Performance Embedded Computing

DTIC Science & Technology

2010-07-22

dependent , providing a natural bandwidth match between compute cores and the memory subsystem. • High Bandwidth Dcnsity. Waveguides crossing the chip...simulate this memory access architecture on a 2S6-core chip with a concentrated 64-node network lIsing detailed traces of high-performance embedded...memory modulcs, wc placc memory access poi nts (MAPs) around the pcriphery of the chip connected to thc nctwork. These MAPs, shown in Figure 4, contain

[Cortical functional connectivity during retention of affective pictures in working memory: EEG-source theta coherence analysis].

PubMed

Machinskaya, R I; Rozovskaya, R I; Kurgansky, A V; Pechenkova, E V

2016-01-01

A pattern of cortical functional connectivity in the source space was studied in a group of right-handed adult participants (N = 44:17 women, 27 men, aged M = 29.61 ± 6.45 years) who retained in their working memory (WM) traces of realistic pictures of positive, neutral, and negative emotional valence while in their working memory (WM) while performing same different task in which participants had to compare an etalon picture against a target picture that followed after a specified delay. A coherence (COH) between pairs of cortical sources chosen in advance according to fMRI data was estimated in the theta frequency range for the period of time preceding the etalon stimulus, distinct sets of functional links are found. The links of the first type that presumably reflect the involvement of sustained attention were between the dorsal anterior cingulate cortex, the prefrontal areas, and temporal areas of the right hemispheres. When compared to the rest period, links of this type showed strengthening not only during the retention period but also during the period preceding the etalon picture. The links of the second type presumably reflecting a progressive neocortex-to-hippocampus functional integration with increasing memory load and strengthened exclusively during retention period. Those links were between parietal, temporal and prefrontal cortices in the lateral surface of both hemispheres with the additional inclusion of the posterior cingulate cortex and the medial parietal cortex in the left hemisphere. An impact of emotional valence onto the strength and topography of the functional links of the second type was found. In the left hemisphere, an increase in the strength of cortical interaction was more pronounced for pictures of positive valence than for pictures of either neutral or negative valences. When compared to the pictures of neutral valence, the retention of pictorial information of both positive and negative valence showed some extraneous integration of the cortical areas for the theta rhythm. This finding might be related to the additional load exerted by emotionally colored pictures onto the mechanisms of short-time retention of visual information.

The Hippocampus Remains Activated over the Long Term for the Retrieval of Truly Episodic Memories

PubMed Central

Harand, Caroline; Bertran, Françoise; La Joie, Renaud; Landeau, Brigitte; Mézenge, Florence; Desgranges, Béatrice; Peigneux, Philippe; Eustache, Francis; Rauchs, Géraldine

2012-01-01

The role of the hippocampus in declarative memory consolidation is a matter of intense debate. We investigated the neural substrates of memory retrieval for recent and remote information using functional magnetic resonance imaging (fMRI). 18 young, healthy participants learned a series of pictures. Then, during two fMRI recognition sessions, 3 days and 3 months later, they had to determine whether they recognized or not each picture using the “Remember/Know” procedure. Presentation of the same learned images at both delays allowed us to track the evolution of memories and distinguish consistently episodic memories from those that were initially episodic and then became familiar or semantic over time and were retrieved without any contextual detail. Hippocampal activation decreased over time for initially episodic, later semantic memories, but remained stable for consistently episodic ones, at least in its posterior part. For both types of memories, neocortical activations were observed at both delays, notably in the ventromedial prefrontal and anterior cingulate cortices. These activations may reflect a gradual reorganization of memory traces within neural networks. Our data indicate maintenance and strengthening of hippocampal and cortico-cortical connections in the consolidation and retrieval of episodic memories over time, in line with the Multiple Trace theory (Nadel and Moscovitch, 1997). At variance, memories becoming semantic over time consolidate through strengthening of cortico-cortical connections and progressive disengagement of the hippocampus. PMID:22937055

Serial-position effects for items and relations in short-term memory.

PubMed

Jones, Tim; Oberauer, Klaus

2013-04-01

Two experiments used immediate probed recall of words to investigate serial-position effects. Item memory was tested through probing with a semantic category. Relation memory was tested through probing with the word's spatial location of presentation. Input order and output order were deconfounded by presenting and probing items in different orders. Primacy and recency effects over input position were found for both item memory and relation memory. Both item and relation memory declined over output position. The finding of a U-shaped input position function for item memory rules out an explanation purely in terms of positional confusions (e.g., edge effects). Either these serial-position effects arise from variations in the intrinsic memory strength of the items, or they arise from variations in the strength of item-position bindings, together with retrieval by scanning.

The sensory strength of voluntary visual imagery predicts visual working memory capacity.

PubMed

Keogh, Rebecca; Pearson, Joel

2014-10-09

How much we can actively hold in mind is severely limited and differs greatly from one person to the next. Why some individuals have greater capacities than others is largely unknown. Here, we investigated why such large variations in visual working memory (VWM) capacity might occur, by examining the relationship between visual working memory and visual mental imagery. To assess visual working memory capacity participants were required to remember the orientation of a number of Gabor patches and make subsequent judgments about relative changes in orientation. The sensory strength of voluntary imagery was measured using a previously documented binocular rivalry paradigm. Participants with greater imagery strength also had greater visual working memory capacity. However, they were no better on a verbal number working memory task. Introducing a uniform luminous background during the retention interval of the visual working memory task reduced memory capacity, but only for those with strong imagery. Likewise, for the good imagers increasing background luminance during imagery generation reduced its effect on subsequent binocular rivalry. Luminance increases did not affect any of the subgroups on the verbal number working memory task. Together, these results suggest that luminance was disrupting sensory mechanisms common to both visual working memory and imagery, and not a general working memory system. The disruptive selectivity of background luminance suggests that good imagers, unlike moderate or poor imagers, may use imagery as a mnemonic strategy to perform the visual working memory task. © 2014 ARVO.

The Levels of Processing Conceptualization of Human Memory: Some Empirical and Theoretical Issues,

DTIC Science & Technology

1984-12-01

levels -of- processing (LOP) framework was introduced by Craik and Lockhart in 1972...G. H. A multicomponent theory of the memory trace. In F. I. M. Craik and R. S. Lockhart , Levels of 6 processing : A framework for memory research... Lockhart , R. S. Levels of processing : A framework of memory research. Journal of Verbal Learning and Verbal Behavior, 1972, 11, 671-684. 25. Craik , F.

Perception and the strongest sensory memory trace of multi-stable displays both form shortly after the stimulus onset.

PubMed

Pastukhov, Alexander

2016-02-01

We investigated the relation between perception and sensory memory of multi-stable structure-from-motion displays. The latter is an implicit visual memory that reflects a recent history of perceptual dominance and influences only the initial perception of multi-stable displays. First, we established the earliest time point when the direction of an illusory rotation can be reversed after the display onset (29-114 ms). Because our display manipulation did not bias perception towards a specific direction of illusory rotation but only signaled the change in motion, this means that the perceptual dominance was established no later than 29-114 ms after the stimulus onset. Second, we used orientation-selectivity of sensory memory to establish which display orientation produced the strongest memory trace and when this orientation was presented during the preceding prime interval (80-140 ms). Surprisingly, both estimates point towards the time interval immediately after the display onset, indicating that both perception and sensory memory form at approximately the same time. This suggests a tighter integration between perception and sensory memory than previously thought, warrants a reconsideration of its role in visual perception, and indicates that sensory memory could be a unique behavioral correlate of the earlier perceptual inference that can be studied post hoc.

Performance Analysis of Multilevel Parallel Applications on Shared Memory Architectures

NASA Technical Reports Server (NTRS)

Jost, Gabriele; Jin, Haoqiang; Labarta, Jesus; Gimenez, Judit; Caubet, Jordi; Biegel, Bryan A. (Technical Monitor)

2002-01-01

In this paper we describe how to apply powerful performance analysis techniques to understand the behavior of multilevel parallel applications. We use the Paraver/OMPItrace performance analysis system for our study. This system consists of two major components: The OMPItrace dynamic instrumentation mechanism, which allows the tracing of processes and threads and the Paraver graphical user interface for inspection and analyses of the generated traces. We describe how to use the system to conduct a detailed comparative study of a benchmark code implemented in five different programming paradigms applicable for shared memory

Bridging consciousness and cognition in memory and perception: evidence for both state and strength processes.

PubMed

Aly, Mariam; Yonelinas, Andrew P

2012-01-01

Subjective experience indicates that mental states are discrete, in the sense that memories and perceptions readily come to mind in some cases, but are entirely unavailable to awareness in others. However, a long history of psychophysical research has indicated that the discrete nature of mental states is largely epiphenomenal and that mental processes vary continuously in strength. We used a novel combination of behavioral methodologies to examine the processes underlying perception of complex images: (1) analysis of receiver operating characteristics (ROCs), (2) a modification of the change-detection flicker paradigm, and (3) subjective reports of conscious experience. These methods yielded converging results showing that perceptual judgments reflect the combined, yet functionally independent, contributions of two processes available to conscious experience: a state process of conscious perception and a strength process of knowing; processes that correspond to recollection and familiarity in long-term memory. In addition, insights from the perception experiments led to the discovery of a new recollection phenomenon in a long-term memory change detection paradigm. The apparent incompatibility between subjective experience and theories of cognition can be understood within a unified state-strength framework that links consciousness to cognition across the domains of perception and memory.

Bridging Consciousness and Cognition in Memory and Perception: Evidence for Both State and Strength Processes

PubMed Central

Aly, Mariam; Yonelinas, Andrew P.

2012-01-01

Subjective experience indicates that mental states are discrete, in the sense that memories and perceptions readily come to mind in some cases, but are entirely unavailable to awareness in others. However, a long history of psychophysical research has indicated that the discrete nature of mental states is largely epiphenomenal and that mental processes vary continuously in strength. We used a novel combination of behavioral methodologies to examine the processes underlying perception of complex images: (1) analysis of receiver operating characteristics (ROCs), (2) a modification of the change-detection flicker paradigm, and (3) subjective reports of conscious experience. These methods yielded converging results showing that perceptual judgments reflect the combined, yet functionally independent, contributions of two processes available to conscious experience: a state process of conscious perception and a strength process of knowing; processes that correspond to recollection and familiarity in long-term memory. In addition, insights from the perception experiments led to the discovery of a new recollection phenomenon in a long-term memory change detection paradigm. The apparent incompatibility between subjective experience and theories of cognition can be understood within a unified state-strength framework that links consciousness to cognition across the domains of perception and memory. PMID:22272314

The fate of object memory traces under change detection and change blindness.

PubMed

Busch, Niko A

2013-07-03

Observers often fail to detect substantial changes in a visual scene. This so-called change blindness is often taken as evidence that visual representations are sparse and volatile. This notion rests on the assumption that the failure to detect a change implies that representations of the changing objects are lost all together. However, recent evidence suggests that under change blindness, object memory representations may be formed and stored, but not retrieved. This study investigated the fate of object memory representations when changes go unnoticed. Participants were presented with scenes consisting of real world objects, one of which changed on each trial, while recording event-related potentials (ERPs). Participants were first asked to localize where the change had occurred. In an additional recognition task, participants then discriminated old objects, either from the pre-change or the post-change scene, from entirely new objects. Neural traces of object memories were studied by comparing ERPs for old and novel objects. Participants performed poorly in the detection task and often failed to recognize objects from the scene, especially pre-change objects. However, a robust old/novel effect was observed in the ERP, even when participants were change blind and did not recognize the old object. This implicit memory trace was found both for pre-change and post-change objects. These findings suggest that object memories are stored even under change blindness. Thus, visual representations may not be as sparse and volatile as previously thought. Rather, change blindness may point to a failure to retrieve and use these representations for change detection. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of memory consolidation and evocation in rats by proton induced X-ray emission

NASA Astrophysics Data System (ADS)

Jobim, P. F. C.; dos Santos, C. E. I.; Maurmann, N.; Reolon, G. K.; Debastiani, R.; Pedroso, T. R.; Carvalho, L. M.; Dias, J. F.

2014-08-01

It is well known that trace elements such as Mg, Ca, Fe, Cu and Zn have a key role in synapse plasticity and learning. Learning process is conventionally divided in three distinct and complementary stages: memory acquisition, consolidation and evocation. Consolidation is the stabilization of the synaptic trace formed by acquisition, while evocation is the recall of this trace. Ion-based techniques capable of providing information concerning the elemental composition of organic tissues may be helpful to improve our understanding on memory consolidation and evocation processes. In particular, the Particle-Induced X-ray Emission (PIXE) technique can be used to analyze different biological tissues with good accuracy. In this work we explore the versatility of PIXE to measure the elemental concentrations in rat brain tissues in order to establish any possible correlation between them and the memory consolidation and evocation processes. To this end, six groups of middle-age male Wistar rats were trained and tested in a step-down Inhibitory Avoidance conditioning. After the behavior tests, the animals were decapitated in accordance with the legal procedures and their brains were removed and dissected for the PIXE analyses. The results demonstrated that there are differences in the elemental concentration among the groups and such variations may be associated with their availability to the learning processes (by memory consolidation and evocation). Moreover, the control groups circumvent the possibility that a non-specific event involved in learning tasks cause such variations. Our results suggest that PIXE may be a useful tool to investigate memory consolidation and evocation in animal models.

The functional impact of mental imagery on conscious perception

PubMed Central

Pearson, Joel; Clifford, Colin; Tong, Frank

2008-01-01

Summary Mental imagery has been proposed to contribute to a variety of high-level cognitive functions, including memory encoding and retrieval, navigation and spatial planning, and even social communication and language comprehension [1–5]. However, it is debated whether mental imagery relies on the same sensory representations as perception [1, 6–10], and if so, what functional consequences such an overlap might have on perception itself. We report novel evidence that single instances of imagery can have a pronounced facilitatory influence on subsequent conscious perception. Either seeing or imagining a specific pattern could strongly bias which of two competing stimuli reach awareness during binocular rivalry. Effects of imagery and perception were location- and orientation-specific, accumulated in strength over time, and survived an intervening visual task lasting several seconds prior to presentation of the rivalry display. Interestingly, effects of imagery differed from those of feature-based attention. The results demonstrate that imagery, in the absence of any incoming visual signals, leads to the formation of a short-term sensory trace that can bias future perception, suggesting a means by which high-level processes that support imagination and memory retrieval may shape low-level sensory representations. PMID:18583132

Current Research and Potential Applications of the Concealed Information Test: An Overview

PubMed Central

Ben-Shakhar, Gershon

2012-01-01

Research interest in psychophysiological detection of deception has significantly increased since the September 11 terror attack in the USA. In particular, the concealed information test (CIT), designed to detect memory traces that can connect suspects to a certain crime, has been extensively studied. In this paper I will briefly review several psychophysiological detection paradigms that have been studied, with a focus on the CIT. The theoretical background of the CIT, its strength and weaknesses, its potential applications as well as research finings related to its validity (based on a recent meta-analytic study), will be discussed. Several novel research directions, with a focus on factors that may affect CIT detection in realistic settings (e.g., memory for crime details; the effect of emotional stress during crime execution) will be described. Additionally, research focusing on mal-intentions and attempts to detect terror networks using information gathered from groups of suspects using both the standard CIT and the searching CIT will be reviewed. Finally, implications of current research to the actual application of the CIT will be discussed and several recommendations that can enhance the use of the CIT will be made. PMID:23060826

[Global Atmospheric Chemistry/Transport Modeling and Data-Analysis

NASA Technical Reports Server (NTRS)

Prinn, Ronald G.

1999-01-01

This grant supported a global atmospheric chemistry/transport modeling and data- analysis project devoted to: (a) development, testing, and refining of inverse methods for determining regional and global transient source and sink strengths for trace gases; (b) utilization of these inverse methods which use either the Model for Atmospheric Chemistry and Transport (MATCH) which is based on analyzed observed winds or back- trajectories calculated from these same winds for determining regional and global source and sink strengths for long-lived trace gases important in ozone depletion and the greenhouse effect; (c) determination of global (and perhaps regional) average hydroxyl radical concentrations using inverse methods with multiple "titrating" gases; and (d) computation of the lifetimes and spatially resolved destruction rates of trace gases using 3D models. Important ultimate goals included determination of regional source strengths of important biogenic/anthropogenic trace gases and also of halocarbons restricted by the Montreal Protocol and its follow-on agreements, and hydrohalocarbons now used as alternatives to the above restricted halocarbons.

Electrode configuration and signal subtraction technique for single polarity charge carrier sensing in ionization detectors

DOEpatents

Luke, Paul

1996-01-01

An ionization detector electrode and signal subtraction apparatus and method provides at least one first conductive trace formed onto the first surface of an ionization detector. The first surface opposes a second surface of the ionization detector. At least one second conductive trace is also formed on the first surface of the ionization detector in a substantially interlaced and symmetrical pattern with the at least one first conductive trace. Both of the traces are held at a voltage potential of a first polarity type. By forming the traces in a substantially interlaced and symmetric pattern, signals generated by a charge carrier are substantially of equal strength with respect to both of the traces. The only significant difference in measured signal strength occurs when the charge carrier moves to within close proximity of the traces and is received at the collecting trace. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge and to determine the position at which the charge carrier originated within the ionization detector.

Electrode configuration and signal subtraction technique for single polarity charge carrier sensing in ionization detectors

DOEpatents

Luke, P.

1996-06-25

An ionization detector electrode and signal subtraction apparatus and method provide at least one first conductive trace formed onto the first surface of an ionization detector. The first surface opposes a second surface of the ionization detector. At least one second conductive trace is also formed on the first surface of the ionization detector in a substantially interlaced and symmetrical pattern with the at least one first conductive trace. Both of the traces are held at a voltage potential of a first polarity type. By forming the traces in a substantially interlaced and symmetric pattern, signals generated by a charge carrier are substantially of equal strength with respect to both of the traces. The only significant difference in measured signal strength occurs when the charge carrier moves to within close proximity of the traces and is received at the collecting trace. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge and to determine the position at which the charge carrier originated within the ionization detector. 9 figs.

Word Length Effects in Long-Term Memory

ERIC Educational Resources Information Center

Tehan, Gerald; Tolan, Georgina Anne

2007-01-01

The word length effect has been a central feature of theorising about immediate memory. The notion that short-term memory traces rapidly decay unless refreshed by rehearsal is based primarily upon the finding that serial recall for short words is better than that for long words. The decay account of the word length effect has come under pressure…

Spatial Working Memory Capacity Predicts Bias in Estimates of Location

ERIC Educational Resources Information Center

Crawford, L. Elizabeth; Landy, David; Salthouse, Timothy A.

2016-01-01

Spatial memory research has attributed systematic bias in location estimates to a combination of a noisy memory trace with a prior structure that people impose on the space. Little is known about intraindividual stability and interindividual variation in these patterns of bias. In the current work, we align recent empirical and theoretical work on…

Calcineurin Inhibition Blocks Within-, but Not Between-Session Fear Extinction in Mice

ERIC Educational Resources Information Center

Almeida-Corrêa, Suellen; Moulin, Thiago C.; Carneiro, Clarissa F. D.; Gonçalves, Marina M. C.; Junqueira, Lara S.; Amaral, Olavo B.

2015-01-01

Memory extinction involves the formation of a new associative memory that inhibits a previously conditioned association. Nonetheless, it could also depend on weakening of the original memory trace if extinction is assumed to have multiple components. The phosphatase calcineurin (CaN) has been described as being involved in extinction but not in…

Synapsin Determines Memory Strength after Punishment- and Relief-Learning

PubMed Central

Niewalda, Thomas; Michels, Birgit; Jungnickel, Roswitha; Diegelmann, Sören; Kleber, Jörg; Kähne, Thilo

2015-01-01

Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: “negative” memories for stimuli preceding them and “positive” memories for stimuli experienced at the moment of “relief.” Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training (“forward conditioning” of the odor), whereas after shock-odor training (“backward conditioning” of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences. PMID:25972175

Synapsin determines memory strength after punishment- and relief-learning.

PubMed

Niewalda, Thomas; Michels, Birgit; Jungnickel, Roswitha; Diegelmann, Sören; Kleber, Jörg; Kähne, Thilo; Gerber, Bertram

2015-05-13

Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: "negative" memories for stimuli preceding them and "positive" memories for stimuli experienced at the moment of "relief." Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training ("forward conditioning" of the odor), whereas after shock-odor training ("backward conditioning" of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences. Copyright © 2015 Niewalda et al.

A SEMantic and EPisodic Memory Test (SEMEP) Developed within the Embodied Cognition Framework: Application to Normal Aging, Alzheimer's Disease and Semantic Dementia.

PubMed

Vallet, Guillaume T; Hudon, Carol; Bier, Nathalie; Macoir, Joël; Versace, Rémy; Simard, Martine

2017-01-01

Embodiment has highlighted the importance of sensory-motor components in cognition. Perception and memory are thus very tightly bound together, and episodic and semantic memories should rely on the same grounded memory traces. Reduced perception should then directly reduce the ability to encode and retrieve an episodic memory, as in normal aging. Multimodal integration deficits, as in Alzheimer's disease, should lead to more severe episodic memory impairment. The present study introduces a new memory test developed to take into account these assumptions. The SEMEP (SEMantic-Episodic) memory test proposes to assess conjointly semantic and episodic knowledge across multiple tasks: semantic matching, naming, free recall, and recognition. The performance of young adults is compared to healthy elderly adults (HE), patients with Alzheimer's disease (AD), and patients with semantic dementia (SD). The results show specific patterns of performance between the groups. HE commit memory errors only for presented but not to be remembered items. AD patients present the worst episodic memory performance associated with intrusion errors (recall or recognition of items never presented). They were the only group to not benefit from a visual isolation (addition of a yellow background), a method known to increase the distinctiveness of the memory traces. Finally, SD patients suffer from the most severe semantic impairment. To conclude, confusion errors are common across all the elderly groups, whereas AD was the only group to exhibit regular intrusion errors and SD patients to show severe semantic impairment.

Sleep enhances false memories depending on general memory performance.

PubMed

Diekelmann, Susanne; Born, Jan; Wagner, Ullrich

2010-04-02

Memory is subject to dynamic changes, sometimes giving rise to the formation of false memories due to biased processes of consolidation or retrieval. Sleep is known to benefit memory consolidation through an active reorganization of representations whereas acute sleep deprivation impairs retrieval functions. Here, we investigated whether sleep after learning and sleep deprivation at retrieval enhance the generation of false memories in a free recall test. According to the Deese, Roediger, McDermott (DRM) false memory paradigm, subjects learned lists of semantically associated words (e.g., "night", "dark", "coal", etc.), lacking the strongest common associate or theme word (here: "black"). Free recall was tested after 9h following a night of sleep, a night of wakefulness (sleep deprivation) or daytime wakefulness. Compared with memory performance after a retention period of daytime wakefulness, both post-learning nocturnal sleep as well as acute sleep deprivation at retrieval significantly enhanced false recall of theme words. However, these effects were only observed in subjects with low general memory performance. These data point to two different ways in which sleep affects false memory generation through semantic generalization: one acts during consolidation on the memory trace per se, presumably by active reorganization of the trace in the post-learning sleep period. The other is related to the recovery function of sleep and affects cognitive control processes of retrieval. Both effects are unmasked when the material is relatively weakly encoded. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

A Hamiltonian driven quantum-like model for overdistribution in episodic memory recollection.

NASA Astrophysics Data System (ADS)

Broekaert, Jan B.; Busemeyer, Jerome R.

2017-06-01

While people famously forget genuine memories over time, they also tend to mistakenly over-recall equivalent memories concerning a given event. The memory phenomenon is known by the name of episodic overdistribution and occurs both in memories of disjunctions and partitions of mutually exclusive events and has been tested, modeled and documented in the literature. The total classical probability of recalling exclusive sub-events most often exceeds the probability of recalling the composed event, i.e. a subadditive total. We present a Hamiltonian driven propagation for the Quantum Episodic Memory model developed by Brainerd (et al., 2015) for the episodic memory overdistribution in the experimental immediate item false memory paradigm (Brainerd and Reyna, 2008, 2010, 2015). Following the Hamiltonian method of Busemeyer and Bruza (2012) our model adds time-evolution of the perceived memory state through the stages of the experimental process based on psychologically interpretable parameters - γ_c for recollection capability of cues, κ_p for bias or description-dependence by probes and β for the average gist component in the memory state at start. With seven parameters the Hamiltonian model shows good accuracy of predictions both in the EOD-disjunction and in the EOD-subadditivity paradigm. We noticed either an outspoken preponderance of the gist over verbatim trace, or the opposite, in the initial memory state when β is real. Only for complex β a mix of both traces is present in the initial state for the EOD-subadditivity paradigm.

Reconsolidation of memory: a decade of debate.

PubMed

Besnard, Antoine; Caboche, Jocelyne; Laroche, Serge

2012-10-01

Memory consolidation refers to a slow process that stabilises a memory trace after initial acquisition of novel events. The consolidation theory posits that once a memory is stored in the brain, it remains fixed for the lifetime of the memory. However, compelling evidence has suggested that upon recall, memories can re-enter a state of transient instability, requiring further stabilisation to be available once again for recall. Since its rehabilitation in the past ten years, this process of reconsolidation of memory after recall stimulated intense debates in the field of cognitive neuroscience. In this review we compile this plentiful literature with a particular emphasis on some of the key questions that have emerged from the reconsolidation theory. We focus on tracing the characterisation of the boundary conditions that constrain the occurrence of memory reconsolidation. We also discuss accumulating evidence supporting the idea that reconsolidation, as implied by its definition, is not a mere repetition of consolidation. We review seminal studies that uncovered specific mechanisms recruited during reconsolidation that are not always crucially involved in consolidation. We next address the physiological significance of reconsolidation since several lines of evidence support the idea that reconsolidation, as opposed to consolidation, may offer a unique opportunity to update memories. We finally discuss recent evidence for or against the potential that the process of memory reconsolidation offers for ongoing efforts to develop novel strategies to combat pathogenic memories. Copyright © 2012 Elsevier Ltd. All rights reserved.

Both trace and delay conditioned eyeblink responding can be dissociated from outcome expectancy.

PubMed

Weidemann, Gabrielle; Broderick, Joshua; Lovibond, Peter F; Mitchell, Christopher J

2012-01-01

Squire and colleagues have proposed that trace and delay eyeblink conditioning are fundamentally different kinds of learning: trace conditioning requires acquisition of a conscious declarative memory for the stimulus contingencies whereas delay conditioning does not. Declarative memory in trace conditioning is thought to generate conditioned responding through the activation of a conscious expectancy for when the unconditioned stimulus (US) is going to occur. Perruchet (1985) has previously shown that in a 50% partial reinforcement design it is possible to dissociate single cue delay eyeblink conditioning from conscious expectancy for the US by examining performance over runs of reinforced and nonreinforced trials. Clark, Manns, and Squire (2001) claim that this dissociation does not occur in trace eyeblink conditioning. In the present experiment we examined the Perruchet effect for short, moderate, and long trace intervals (600, 1000, and 1400 ms) and for the equivalent interstimulus intervals (ISIs) in a delay conditioning procedure. We found evidence for a dissociation of eyeblink CRs and US expectancy over runs regardless of whether there was a delay or a trace arrangement of cues. The reasons for the Perruchet effect are still unclear, but the present data suggest that it does not depend on a separate nondeclarative system of the type proposed by Squire and colleagues. (c) 2012 APA, all rights reserved.

Modeling phoneme perception. II: A model of stop consonant discrimination.

PubMed

van Hessen, A J; Schouten, M E

1992-10-01

Combining elements from two existing theories of speech sound discrimination, dual process theory (DPT) and trace context theory (TCT), a new theory, called phoneme perception theory, is proposed, consisting of a long-term phoneme memory, a context-coding memory, and a trace memory, each with its own time constants. This theory is tested by means of stop-consonant discrimination data in which interstimulus interval (ISI; values of 100, 300, and 2000 ms) is an important variable. It is shown that discrimination in which labeling plays an important part (2IFC and AX between category) benefits from increased ISI, whereas discrimination in which only sensory traces are compared (AX within category), decreases with increasing ISI. The theory is also tested on speech discrimination data from the literature in which ISI is a variable [Pisoni, J. Acoust. Soc. Am. 36, 277-282 (1964); Cowan and Morse, J. Acoust. Soc. Am. 79, 500-507 (1986)]. It is concluded that the number of parameters in trace context theory is not sufficient to account for most speech-sound discrimination data and that a few additional assumptions are needed, such as a form of sublabeling, in which subjects encode the quality of a stimulus as a member of a category, and which requires processing time.

Tracing a Route and Finding a Shortcut: The Working Memory, Motivational, and Personality Factors Involved.

PubMed

Pazzaglia, Francesca; Meneghetti, Chiara; Ronconi, Lucia

2018-01-01

Wayfinding (WF) is the ability to move around efficiently and find the way from a starting point to a destination. It is a component of spatial navigation, a coordinate and goal-directed movement of one's self through the environment. In the present study, the relationship between WF tasks (route tracing and shortcut finding) and individual factors were explored with the hypothesis that WF tasks would be predicted by different types of cognitive, affective, motivational variables, and personality factors. A group of 116 university students (88 F.) were conducted along a route in a virtual environment and then asked first to trace the same route again, and then to find a shortcut between the start and end points. Several instruments assessing visuospatial working memory, mental rotation ability, self-efficacy, spatial anxiety, positive attitude to exploring, and personality traits were administered. The results showed that a latent spatial ability factor (measured with the visuospatial working memory and mental rotations tests) - controlled for gender - predicted route-tracing performance, while self-report measures of anxiety, efficacy, and pleasure in exploring, and some personality traits were more likely to predict shortcut-finding performance. We concluded that both personality and cognitive abilities affect WF performance, but differently, depending on the requirements of the task.

Deficits in hippocampus-mediated Pavlovian conditioning in endogenous hypercortisolism.

PubMed

Grillon, Christian; Smith, Kathryn; Haynos, Ann; Nieman, Lynnette K

2004-12-01

Elevated endogenous levels of corticosteroids cause neural dysfunction and loss, especially within the hippocampus, as well as cognitive impairment in hippocampus-mediated tasks. Because Cushing's syndrome patients suffer from hypercortisolism, they represent a unique opportunity to study the impact of elevated glucocorticoids on cognitive functions. The aim of this study was to examine the performance of Cushing's syndrome patients on trace eyeblink conditioning, a cross-species, hippocampal-mediated test of learning and memory. Eleven Cushing's syndrome patients and 11 healthy control subjects participated in an eyeblink trace conditioning test (1000-msec trace) and a task of declarative memory for words. Salivary cortisol was collected in both the patients and the control subjects, and urinary free cortisol was collected in the patients only. The patients exhibited fewer conditional responses and remembered fewer words, compared with the control subjects. Cortisol levels correlated with immediate and delayed declarative memory only. Conditional response correlated with delayed recall after controlling for the magnitude of unconditional response. The integrity of the hippocampus seems to be compromised in Cushing's syndrome patients. Trace eyeblink conditioning might be useful both as a clinical tool to examine changes in hippocampus function in Cushing's disease patients and as a translational tool of research on the impact of chronic exposure of glucocorticoids.

Rapid shape memory TEMPO-oxidized cellulose nanofibers/polyacrylamide/gelatin hydrogels with enhanced mechanical strength.

PubMed

Li, Nan; Chen, Wei; Chen, Guangxue; Tian, Junfei

2017-09-01

TEMPO-oxidized cellulose nanofibers/polyacrylamide/gelatin shape memory hydrogels were successfully fabricated through a facile in-situ free-radical polymerization method, and double network was formed by chemically cross-linked polyacrylamide (PAM) network and physically cross-linked gelatin network. TEMPO-oxidized cellulose nanofibers (TOCNs) were introduced to improve the mechanical properties of the hydrogel. The structure, shape memory behaviors and mechanical properties of the resulting composite gels with varied gel compositions were investigated. The results obtained from those different studies revealed that TOCNs, gelatin, and PAM could mix with each other homogeneously. Due to the thermoreversible nature of the gelatin network, the composite hydrogels exhibited attractive thermo-induced shape memory properties. In addition, good mechanical properties (strength >200kPa, strain >650%) were achieved. Such composite hydrogels with good shape memory behavior and enhanced mechanical strength would be an attractive candidate for a wide variety of applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

On the Information Content of Program Traces

NASA Technical Reports Server (NTRS)

Frumkin, Michael; Hood, Robert; Yan, Jerry; Saini, Subhash (Technical Monitor)

1998-01-01

Program traces are used for analysis of program performance, memory utilization, and communications as well as for program debugging. The trace contains records of execution events generated by monitoring units inserted into the program. The trace size limits the resolution of execution events and restricts the user's ability to analyze the program execution. We present a study of the information content of program traces and develop a coding scheme which reduces the trace size to the limit given by the trace entropy. We apply the coding to the traces of AIMS instrumented programs executed on the IBM SPA and the SCSI Power Challenge and compare it with other coding methods. Our technique shows size of the trace can be reduced by more than a factor of 5.

Transcriptional profiling reveals regulated genes in the hippocampus during memory formation

NASA Technical Reports Server (NTRS)

Donahue, Christine P.; Jensen, Roderick V.; Ochiishi, Tomoyo; Eisenstein, Ingrid; Zhao, Mingrui; Shors, Tracey; Kosik, Kenneth S.

2002-01-01

Transcriptional profiling (TP) offers a powerful approach to identify genes activated during memory formation and, by inference, the molecular pathways involved. Trace eyeblink conditioning is well suited for the study of regional gene expression because it requires the hippocampus, whereas the highly parallel task, delay conditioning, does not. First, we determined when gene expression was most regulated during trace conditioning. Rats were exposed to 200 trials per day of paired and unpaired stimuli each day for 4 days. Changes in gene expression were most apparent 24 h after exposure to 200 trials. Therefore, we profiled gene expression in the hippocampus 24 h after 200 trials of trace eyeblink conditioning, on multiple arrays using additional animals. Of 1,186 genes on the filter array, seven genes met the statistical criteria and were also validated by real-time polymerase chain reaction. These genes were growth hormone (GH), c-kit receptor tyrosine kinase (c-kit), glutamate receptor, metabotropic 5 (mGluR5), nerve growth factor-beta (NGF-beta), Jun oncogene (c-Jun), transmembrane receptor Unc5H1 (UNC5H1), and transmembrane receptor Unc5H2 (UNC5H2). All these genes, except for GH, were downregulated in response to trace conditioning. GH was upregulated; therefore, we also validated the downregulation of the GH inhibitor, somatostatin (SST), even though it just failed to meet criteria on the arrays. By during situ hybridization, GH was expressed throughout the cell layers of the hippocampus in response to trace conditioning. None of the genes regulated in trace eyeblink conditioning were similarly affected by delay conditioning, a task that does not require the hippocampus. These findings demonstrate that transcriptional profiling can exhibit a repertoire of genes sensitive to the formation of hippocampal-dependent associative memories.

BAIAP2 is related to emotional modulation of human memory strength.

PubMed

Luksys, Gediminas; Ackermann, Sandra; Coynel, David; Fastenrath, Matthias; Gschwind, Leo; Heck, Angela; Rasch, Bjoern; Spalek, Klara; Vogler, Christian; Papassotiropoulos, Andreas; de Quervain, Dominique

2014-01-01

Memory performance is the result of many distinct mental processes, such as memory encoding, forgetting, and modulation of memory strength by emotional arousal. These processes, which are subserved by partly distinct molecular profiles, are not always amenable to direct observation. Therefore, computational models can be used to make inferences about specific mental processes and to study their genetic underpinnings. Here we combined a computational model-based analysis of memory-related processes with high density genetic information derived from a genome-wide study in healthy young adults. After identifying the best-fitting model for a verbal memory task and estimating the best-fitting individual cognitive parameters, we found a common variant in the gene encoding the brain-specific angiogenesis inhibitor 1-associated protein 2 (BAIAP2) that was related to the model parameter reflecting modulation of verbal memory strength by negative valence. We also observed an association between the same genetic variant and a similar emotional modulation phenotype in a different population performing a picture memory task. Furthermore, using functional neuroimaging we found robust genotype-dependent differences in activity of the parahippocampal cortex that were specifically related to successful memory encoding of negative versus neutral information. Finally, we analyzed cortical gene expression data of 193 deceased subjects and detected significant BAIAP2 genotype-dependent differences in BAIAP2 mRNA levels. Our findings suggest that model-based dissociation of specific cognitive parameters can improve the understanding of genetic underpinnings of human learning and memory.

What Is False Memory Development the Development of? Comment on Brainerd, Reyna, and Ceci (2008)

ERIC Educational Resources Information Center

Howe, Mark L.

2008-01-01

In this commentary, assumptions about the nature and development of children's false memories as described in a recent article by C. J. Brainerd, V. F. Reyna, and S. J. Ceci (2008) are reviewed. Specifically, questions are raised about what drives the development of false memories in fuzzy-trace theory (FTT). Recent studies that challenge a core…

A Buffer Model of Memory Encoding and Temporal Correlations in Retrieval

ERIC Educational Resources Information Center

Lehman, Melissa; Malmberg, Kenneth J.

2013-01-01

Atkinson and Shiffrin's (1968) dual-store model of memory includes structural aspects of memory along with control processes. The rehearsal buffer is a process by which items are kept in mind and long-term episodic traces are formed. The model has been both influential and controversial. Here, we describe a novel variant of Atkinson and Shiffrin's…

The loss of short-term visual representations over time: decay or temporal distinctiveness?

PubMed

Mercer, Tom

2014-12-01

There has been much recent interest in the loss of visual short-term memories over the passage of time. According to decay theory, visual representations are gradually forgotten as time passes, reflecting a slow and steady distortion of the memory trace. However, this is controversial and decay effects can be explained in other ways. The present experiment aimed to reexamine the maintenance and loss of visual information over the short term. Decay and temporal distinctiveness models were tested using a delayed discrimination task, in which participants compared complex and novel objects over unfilled retention intervals of variable length. Experiment 1 found no significant change in the accuracy of visual memory from 2 to 6 s, but the gap separating trials reliably influenced task performance. Experiment 2 found evidence for information loss at a 10-s retention interval, but temporally separating trials restored the fidelity of visual memory, possibly because temporally isolated representations are distinct from older memory traces. In conclusion, visual representations lose accuracy at some point after 6 s, but only within temporally crowded contexts. These findings highlight the importance of temporal distinctiveness within visual short-term memory. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Short- and long-term memory in Drosophila require cAMP signaling in distinct neuron types.

PubMed

Blum, Allison L; Li, Wanhe; Cressy, Mike; Dubnau, Josh

2009-08-25

A common feature of memory and its underlying synaptic plasticity is that each can be dissected into short-lived forms involving modification or trafficking of existing proteins and long-term forms that require new gene expression. An underlying assumption of this cellular view of memory consolidation is that these different mechanisms occur within a single neuron. At the neuroanatomical level, however, different temporal stages of memory can engage distinct neural circuits, a notion that has not been conceptually integrated with the cellular view. Here, we investigated this issue in the context of aversive Pavlovian olfactory memory in Drosophila. Previous studies have demonstrated a central role for cAMP signaling in the mushroom body (MB). The Ca(2+)-responsive adenylyl cyclase RUTABAGA is believed to be a coincidence detector in gamma neurons, one of the three principle classes of MB Kenyon cells. We were able to separately restore short-term or long-term memory to a rutabaga mutant with expression of rutabaga in different subsets of MB neurons. Our findings suggest a model in which the learning experience initiates two parallel associations: a short-lived trace in MB gamma neurons, and a long-lived trace in alpha/beta neurons.

A constrained rasch model of trace redintegration in serial recall.

PubMed

Roodenrys, Steven; Miller, Leonie M

2008-04-01

The notion that verbal short-term memory tasks, such as serial recall, make use of information in long-term as well as in short-term memory is instantiated in many models of these tasks. Such models incorporate a process in which degraded traces retrieved from a short-term store are reconstructed, or redintegrated (Schweickert, 1993), through the use of information in long-term memory. This article presents a conceptual and mathematical model of this process based on a class of item-response theory models. It is demonstrated that this model provides a better fit to three sets of data than does the multinomial processing tree model of redintegration (Schweickert, 1993) and that a number of conceptual accounts of serial recall can be related to the parameters of the model.

Context-dependent memory traces in the crab’s mushroom bodies: Functional support for a common origin of high-order memory centers

PubMed Central

Maza, Francisco Javier; Sztarker, Julieta; Shkedy, Avishag; Peszano, Valeria Natacha; Locatelli, Fernando Federico; Delorenzi, Alejandro

2016-01-01

The hypothesis of a common origin for the high-order memory centers in bilateral animals is based on the evidence that several key features, including gene expression and neuronal network patterns, are shared across several phyla. Central to this hypothesis is the assumption that the arthropods’ higher order neuropils of the forebrain [the mushroom bodies (MBs) of insects and the hemiellipsoid bodies (HBs) of crustaceans] are homologous structures. However, even though involvement in memory processes has been repeatedly demonstrated for the MBs, direct proof of such a role in HBs is lacking. Here, through neuroanatomical and immunohistochemical analysis, we identified, in the crab Neohelice granulata, HBs that resemble the calyxless MBs found in several insects. Using in vivo calcium imaging, we revealed training-dependent changes in neuronal responses of vertical and medial lobes of the HBs. These changes were stimulus-specific, and, like in the hippocampus and MBs, the changes reflected the context attribute of the memory trace, which has been envisioned as an essential feature for the HBs. The present study constitutes functional evidence in favor of a role for the HBs in memory processes, and provides key physiological evidence supporting a common origin of the arthropods’ high-order memory centers. PMID:27856766

Neural evidence for a distinction between short-term memory and the focus of attention.

PubMed

Lewis-Peacock, Jarrod A; Drysdale, Andrew T; Oberauer, Klaus; Postle, Bradley R

2012-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay period activity may, in fact, reflect the focus of attention, rather than STM. We unconfounded attention and memory by causing external and internal shifts of attention away from items that were being actively retained. Multivariate pattern analysis of fMRI indicated that only items within the focus of attention elicited an active neural trace. Activity corresponding to representations of items outside the focus quickly dropped to baseline. Nevertheless, this information was remembered after a brief delay. Our data also show that refocusing attention toward a previously unattended memory item can reactivate its neural signature. The loss of sustained activity has long been thought to indicate a disruption of STM, but our results suggest that, even for small memory loads not exceeding the capacity limits of STM, the active maintenance of a stimulus representation may not be necessary for its short-term retention.

Limits to the usability of iconic memory.

PubMed

Rensink, Ronald A

2014-01-01

Human vision briefly retains a trace of a stimulus after it disappears. This trace-iconic memory-is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report) of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alternating between visible and iconic representations. However, the duration over which it can be used depends on the type of task: some tasks can use iconic memory for at least 240 ms, others for only about 190 ms, while others for no more than about 120 ms. The existence of these different limits suggests that iconic memory may have multiple layers, each corresponding to a particular level of the visual hierarchy. In this view, the inability to use a layer of iconic memory may reflect an inability to maintain feedback connections to the corresponding representation.

Imaging a memory trace over half a life-time in the medial temporal lobe reveals a time-limited role of CA3 neurons in retrieval

PubMed Central

Lux, Vanessa; Atucha, Erika; Kitsukawa, Takashi; Sauvage, Magdalena M

2016-01-01

Whether retrieval still depends on the hippocampus as memories age or relies then on cortical areas remains a major controversy. Despite evidence for a functional segregation between CA1, CA3 and parahippocampal areas, their specific role within this frame is unclear. Especially, the contribution of CA3 is questionable as very remote memories might be too degraded to be used for pattern completion. To identify the specific role of these areas, we imaged brain activity in mice during retrieval of recent, early remote and very remote fear memories by detecting the immediate-early gene Arc. Investigating correlates of the memory trace over an extended period allowed us to report that, in contrast to CA1, CA3 is no longer recruited in very remote retrieval. Conversely, we showed that parahippocampal areas are then maximally engaged. These results suggest a shift from a greater contribution of the trisynaptic loop to the temporoammonic pathway for retrieval. DOI: http://dx.doi.org/10.7554/eLife.11862.001 PMID:26880561

Investigating Strength and Frequency Effects in Recognition Memory Using Type-2 Signal Detection Theory

ERIC Educational Resources Information Center

Higham, Philip A.; Perfect, Timothy J.; Bruno, Davide

2009-01-01

Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower…

Misremembering emotion: Inductive category effects for complex emotional stimuli.

PubMed

Corbin, Jonathan C; Crawford, L Elizabeth; Vavra, Dylan T

2017-07-01

Memories of objects are biased toward what is typical of the category to which they belong. Prior research on memory for emotional facial expressions has demonstrated a bias towards an emotional expression prototype (e.g., slightly happy faces are remembered as happier). We investigate an alternate source of bias in memory for emotional expressions - the central tendency bias. The central tendency bias skews reconstruction of a memory trace towards the center of the distribution for a particular attribute. This bias has been attributed to a Bayesian combination of an imprecise memory for a particular object with prior information about its category. Until now, studies examining the central tendency bias have focused on simple stimuli. We extend this work to socially relevant, complex, emotional facial expressions. We morphed facial expressions on a continuum from sad to happy. Different ranges of emotion were used in four experiments in which participants viewed individual expressions and, after a variable delay, reproduced each face by adjusting a morph to match it. Estimates were biased toward the center of the presented stimulus range, and the bias increased at longer memory delays, consistent with the Bayesian prediction that as trace memory loses precision, category knowledge is given more weight. The central tendency effect persisted within and across emotion categories (sad, neutral, and happy). This article expands the scope of work on inductive category effects to memory for complex, emotional stimuli.

Faster forgetting contributes to impaired spatial memory in the PDAPP mouse: Deficit in memory retrieval associated with increased sensitivity to interference?

PubMed Central

Daumas, Stephanie; Sandin, Johan; Chen, Karen S.; Kobayashi, Dione; Tulloch, Jane; Martin, Stephen J.; Games, Dora; Morris, Richard G.M.

2008-01-01

Two experiments were conducted to investigate the possibility of faster forgetting by PDAPP mice (a well-established model of Alzheimer’s disease as reported by Games and colleagues in an earlier paper). Experiment 1, using mice aged 13–16 mo, confirmed the presence of a deficit in a spatial reference memory task in the water maze by hemizygous PDAPP mice relative to littermate controls. However, after overtraining to a criterion of equivalent navigational performance, a series of memory retention tests revealed faster forgetting in the PDAPP group. Very limited retraining was sufficient to reinstate good memory in both groups, indicating that their faster forgetting may be due to retrieval failure rather than trace decay. In Experiment 2, 6-mo-old PDAPP and controls were required to learn each of a series of spatial locations to criterion with their memory assessed 10 min after learning each location. No memory deficit was apparent in the PDAPP mice initially, but a deficit built up through the series of locations suggestive of increased sensitivity to interference. Faster forgetting and increased interference may each reflect a difficulty in accessing memory traces. This interpretation of one aspect of the cognitive deficit in human mutant APP mice has parallels to deficits observed in patients with Alzheimer’s disease, further supporting the validity of transgenic models of the disease. PMID:18772249

Mediationism and the obfuscation of memory

PubMed Central

Watkins, Michael J.

1996-01-01

Memory theorizing is going nowhere. The reason is that it is rooted in mediationism, the doctrine that memory is mediated by some sort of memory trace. Mediationism is the basic tenet of those who seek the substrate of memory; for students of memory per se it is merely a metaphor, and moreover an unfruitful one, for it cannot be penetrated by the methods of psychology. The rejection of mediationism would serve both to replace mechanistic theories with laws or other modes of explanation and to focus research on the actual experience of memory and on the context in which it occurs. The ensuing advantages are discussed and illustrated. PMID:22478247

Developmental Dissociation Between the Maturation of Procedural Memory and Declarative Memory

PubMed Central

Finn, Amy S.; Kalra, Priya B.; Goetz, Calvin; Leonard, Julia A.; Sheridan, Margaret A.; Gabrieli, John D. E.

2015-01-01

Declarative memory and procedural memory are known to be two fundamentally different kinds of memory that are dissociable in their psychological characteristics and measurement (explicit versus implicit) and in the neural systems that subserve each kind of memory. Declarative memory abilities are known to improve from childhood through young adulthood, but the developmental maturation of procedural memory is largely unknown. We compared 10-year-old children and young adults on measures of declarative memory, working memory capacity, and four measures of procedural memory that have been strongly dissociated from declarative memory (mirror tracing, rotary pursuit, probabilistic classification, and artificial grammar). Children had lesser declarative memory ability and lesser working memory capacity than the adults, but exhibited learning equivalent to adults on all four measures of procedural memory. Declarative and procedural memory are, therefore, developmentally dissociable, with procedural memory being adult-like by age 10 and declarative memory continuing to mature into young adulthood. PMID:26560675

Image Tracing: An Analysis of Its Effectiveness in Children's Pictorial Discrimination Learning

ERIC Educational Resources Information Center

Levin, Joel R.; And Others

1977-01-01

A total of 45 fifth grade students were the subjects of an experiment offering support for a component of learning strategy (memory imagery). Various theoretical explanations of the image-tracing phenomenon are considered, including depth of processing, dual coding and frequency. (MS)

Department of Neurosurgery, Seth Gordhandas Sunderdas Medical College and King Edward VII Memorial (K.E.M.) Hospital, Mumbai.

PubMed

Pandya, Sunil; Goel, Atul

2017-01-01

Seth Gordhandas Sunderdas Medical College and King Edward VII Memorial (K.E.M.) Hospital, Mumbai were inaugurated in 1925. This article traces its illustrious history and of the eminent neurosurgeons who shaped its destiny.

What factors underlie children's susceptibility to semantic and phonological false memories? investigating the roles of language skills and auditory short-term memory.

PubMed

McGeown, Sarah P; Gray, Eleanor A; Robinson, Jamey L; Dewhurst, Stephen A

2014-06-01

Two experiments investigated the cognitive skills that underlie children's susceptibility to semantic and phonological false memories in the Deese/Roediger-McDermott procedure (Deese, 1959; Roediger & McDermott, 1995). In Experiment 1, performance on the Verbal Similarities subtest of the British Ability Scales (BAS) II (Elliott, Smith, & McCulloch, 1997) predicted correct and false recall of semantic lures. In Experiment 2, performance on the Yopp-Singer Test of Phonemic Segmentation (Yopp, 1988) did not predict correct recall, but inversely predicted the false recall of phonological lures. Auditory short-term memory was a negative predictor of false recall in Experiment 1, but not in Experiment 2. The findings are discussed in terms of the formation of gist and verbatim traces as proposed by fuzzy trace theory (Reyna & Brainerd, 1998) and the increasing automaticity of associations as proposed by associative activation theory (Howe, Wimmer, Gagnon, & Plumpton, 2009). Copyright © 2014 Elsevier B.V. All rights reserved.

Consolidation in older adults depends upon competition between resting-state networks

PubMed Central

Jacobs, Heidi I. L.; Dillen, Kim N. H.; Risius, Okka; Göreci, Yasemin; Onur, Oezguer A.; Fink, Gereon R.; Kukolja, Juraj

2015-01-01

Memory encoding and retrieval problems are inherent to aging. To date, however, the effect of aging upon the neural correlates of forming memory traces remains poorly understood. Resting-state fMRI connectivity can be used to investigate initial consolidation. We compared within and between network connectivity differences between healthy young and older participants before encoding, after encoding and before retrieval by means of resting-state fMRI. Alterations over time in the between-network connectivity analyses correlated with retrieval performance, whereas within-network connectivity did not: a higher level of negative coupling or competition between the default mode and the executive networks during the after encoding condition was associated with increased retrieval performance in the older adults, but not in the young group. Data suggest that the effective formation of memory traces depends on an age-dependent, dynamic reorganization of the interaction between multiple, large-scale functional networks. Our findings demonstrate that a cross-network based approach can further the understanding of the neural underpinnings of aging-associated memory decline. PMID:25620930

Memory strength and specificity revealed by pupillometry

PubMed Central

Papesh, Megan H.; Goldinger, Stephen D.; Hout, Michael C.

2011-01-01

Voice-specificity effects in recognition memory were investigated using both behavioral data and pupillometry. Volunteers initially heard spoken words and nonwords in two voices; they later provided confidence-based old/new classifications to items presented in their original voices, changed (but familiar) voices, or entirely new voices. Recognition was more accurate for old-voice items, replicating prior research. Pupillometry was used to gauge cognitive demand during both encoding and testing: Enlarged pupils revealed that participants devoted greater effort to encoding items that were subsequently recognized. Further, pupil responses were sensitive to the cue match between encoding and retrieval voices, as well as memory strength. Strong memories, and those with the closest encoding-retrieval voice matches, resulted in the highest peak pupil diameters. The results are discussed with respect to episodic memory models and Whittlesea’s (1997) SCAPE framework for recognition memory. PMID:22019480

Protein synthesis underlies post-retrieval memory consolidation to a restricted degree only when updated information is obtained

PubMed Central

Rodriguez-Ortiz, Carlos J.; De la Cruz, Vanesa; Gutiérrez, Ranier; Bermudez-Rattoni, Federico

2005-01-01

Consolidation theory proposes that through the synthesis of new proteins recently acquired memories are strengthened over time into a stable long-term memory trace. However, evidence has accumulated suggesting that retrieved memory is susceptible to disruption, seeming to consolidate again (reconsolidate) to be retained in long-term storage. Here we show that intracortical blockade of protein synthesis in the gustatory cortex after retrieval of taste-recognition memory disrupts previously consolidated memory to a restricted degree only if the experience is updated. Our results suggest that retrieved memory can be modified as part of a mechanism for incorporating updated information into previously consolidated memory. PMID:16166395

The molecular biology of memory: cAMP, PKA, CRE, CREB-1, CREB-2, and CPEB

PubMed Central

2012-01-01

The analysis of the contributions to synaptic plasticity and memory of cAMP, PKA, CRE, CREB-1, CREB-2, and CPEB has recruited the efforts of many laboratories all over the world. These are six key steps in the molecular biological delineation of short-term memory and its conversion to long-term memory for both implicit (procedural) and explicit (declarative) memory. I here first trace the background for the clinical and behavioral studies of implicit memory that made a molecular biology of memory storage possible, and then detail the discovery and early history of these six molecular steps and their roles in explicit memory. PMID:22583753

Evidence for Decay in Verbal Short-Term Memory: A Commentary on Berman, Jonides, and Lewis (2009)

ERIC Educational Resources Information Center

Campoy, Guillermo

2012-01-01

M. G. Berman, J. Jonides, and R. L. Lewis (2009) adapted the recent-probes task to investigate the causes of forgetting in short-term memory. In 7 experiments, they studied the persistence of memory traces by assessing the level of proactive interference generated by previous-trial items over a range of intertrial intervals. None of the…

Trade-offs between the accuracy and integrity of autobiographical narrative in memory reconsolidation.

PubMed

Montemayor, Carlos

2015-01-01

Lane et al. propose an integrative model for the reconsolidation of traces in their timely and impressive article. This commentary draws attention to trade-offs between accuracy and self-narrative integrity in the model. The trade-offs concern the sense of agency in memory and its role in both implicit and explicit memory reconsolidation, rather than balances concerning degrees of emotional arousal.

The Effects of Emotion on Episodic Memory for TV Commercials.

ERIC Educational Resources Information Center

Thorson, Esther; Friestad, Marian

Based on the associational nature of memory, the distinction between episodic and semantic memory, and the notion of memory strength, a model was developed of the role of emotion in the memory of television commercials. The model generated the following hypotheses: (1) emotional commercials will more likely be recalled than nonemotional…

Association Between Muscular Strength and Cognition in People With Major Depression or Bipolar Disorder and Healthy Controls.

PubMed

Firth, Joseph; Firth, Josh A; Stubbs, Brendon; Vancampfort, Davy; Schuch, Felipe B; Hallgren, Mats; Veronese, Nicola; Yung, Alison R; Sarris, Jerome

2018-04-18

Objective physical fitness measures, such as handgrip strength, are associated with physical, mental, and cognitive outcomes in the general population. Although people with mental illness experience reduced physical fitness and cognitive impairment, the association between muscular strength and cognition has not been examined to date. To determine associations between maximal handgrip strength and cognitive performance in people with major depression or bipolar disorder and in healthy controls. In a multicenter, population-based study conducted between February 13, 2005, and October 1, 2010, in the United Kingdom, cross-sectional analysis was conducted of baseline data from 110 067 participants in the UK Biobank. Data analysis was performed between August 3 and August 18, 2017. Invitations were mailed to approximately 9.2 million UK homes, recruiting 502 664 adults, all aged 37 to 73 years. Clinically validated measures were used to identify individuals with major recurrent depression (moderate or severe) or bipolar disorder (type I or type II) and healthy controls (those with no indication of present or previous mood disorders). Handgrip dynamometry was used to measure muscular function. Cognitive functioning was assessed using computerized tasks of reaction time, visual memory, number memory, reasoning, and prospective memory. Generalized linear mixed models assessed the association between handgrip strength and cognitive performance, controlling for age, educational level, sex, body weight, and geographic region. Of the 110 067 participants, analyses included 22 699 individuals with major depression (mean [95% range] age, 55.5 [41-68] years; 7936 [35.0%] men), 1475 with bipolar disorder (age, 54.4 [41-68] years; 748 [50.7%] men), and 85 893 healthy controls (age, 53.7 [41-69] years; 43 000 [50.0%] men). In those with major depression, significant positive associations (P < .001) between maximal handgrip strength and improved performance on all 5 cognitive tasks were found, including visual memory (coefficient, -0.146; SE, 0.014), reaction time (coefficient, -0.036; SE, 0.002), reasoning (coefficient, 0.213; SE, 0.02), number memory (coefficient, 0.160; SE, 0.023), and prospective memory (coefficient, 0.341; SE, 0.024). Similar results were found in healthy controls. Among participants with bipolar disorder, handgrip strength was positively associated with improved visual memory (coefficient, -0.129; SE, 0.052; P = .01), reaction time (coefficient, -0.047; SE, 0.007; P < .001), prospective memory (coefficient, 0.262; SE, 0.088; P = .003), and reasoning (coefficient, 0.354; SE, 0.08; P < .001). Grip strength may provide a useful indicator of cognitive impairment in people with major depression and bipolar disorder. Future research should investigate causality, assess the functional implications of handgrip strength in psychiatric populations, and examine how interventions to improve muscular fitness affect neurocognitive status and socio-occupational functioning.

The fate of memory: Reconsolidation and the case of Prediction Error.

PubMed

Fernández, Rodrigo S; Boccia, Mariano M; Pedreira, María E

2016-09-01

The ability to make predictions based on stored information is a general coding strategy. A Prediction-Error (PE) is a mismatch between expected and current events. It was proposed as the process by which memories are acquired. But, our memories like ourselves are subject to change. Thus, an acquired memory can become active and update its content or strength by a labilization-reconsolidation process. Within the reconsolidation framework, PE drives the updating of consolidated memories. Moreover, memory features, such as strength and age, are crucial boundary conditions that limit the initiation of the reconsolidation process. In order to disentangle these boundary conditions, we review the role of surprise, classical models of conditioning, and their neural correlates. Several forms of PE were found to be capable of inducing memory labilization-reconsolidation. Notably, many of the PE findings mirror those of memory-reconsolidation, suggesting a strong link between these signals and memory process. Altogether, the aim of the present work is to integrate a psychological and neuroscientific analysis of PE into a general framework for memory-reconsolidation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory

PubMed Central

Moscovitch, Morris; Rosenbaum, R Shayna; Gilboa, Asaf; Addis, Donna Rose; Westmacott, Robyn; Grady, Cheryl; McAndrews, Mary Pat; Levine, Brian; Black, Sandra; Winocur, Gordon; Nadel, Lynn

2005-01-01

We review lesion and neuroimaging evidence on the role of the hippocampus, and other structures, in retention and retrieval of recent and remote memories. We examine episodic, semantic and spatial memory, and show that important distinctions exist among different types of these memories and the structures that mediate them. We argue that retention and retrieval of detailed, vivid autobiographical memories depend on the hippocampal system no matter how long ago they were acquired. Semantic memories, on the other hand, benefit from hippocampal contribution for some time before they can be retrieved independently of the hippocampus. Even semantic memories, however, can have episodic elements associated with them that continue to depend on the hippocampus. Likewise, we distinguish between experientially detailed spatial memories (akin to episodic memory) and more schematic memories (akin to semantic memory) that are sufficient for navigation but not for re-experiencing the environment in which they were acquired. Like their episodic and semantic counterparts, the former type of spatial memory is dependent on the hippocampus no matter how long ago it was acquired, whereas the latter can survive independently of the hippocampus and is represented in extra-hippocampal structures. In short, the evidence reviewed suggests strongly that the function of the hippocampus (and possibly that of related limbic structures) is to help encode, retain, and retrieve experiences, no matter how long ago the events comprising the experience occurred, and no matter whether the memories are episodic or spatial. We conclude that the evidence favours a multiple trace theory (MTT) of memory over two other models: (1) traditional consolidation models which posit that the hippocampus is a time-limited memory structure for all forms of memory; and (2) versions of cognitive map theory which posit that the hippocampus is needed for representing all forms of allocentric space in memory. PMID:16011544

Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory.

PubMed

Moscovitch, Morris; Rosenbaum, R Shayna; Gilboa, Asaf; Addis, Donna Rose; Westmacott, Robyn; Grady, Cheryl; McAndrews, Mary Pat; Levine, Brian; Black, Sandra; Winocur, Gordon; Nadel, Lynn

2005-07-01

We review lesion and neuroimaging evidence on the role of the hippocampus, and other structures, in retention and retrieval of recent and remote memories. We examine episodic, semantic and spatial memory, and show that important distinctions exist among different types of these memories and the structures that mediate them. We argue that retention and retrieval of detailed, vivid autobiographical memories depend on the hippocampal system no matter how long ago they were acquired. Semantic memories, on the other hand, benefit from hippocampal contribution for some time before they can be retrieved independently of the hippocampus. Even semantic memories, however, can have episodic elements associated with them that continue to depend on the hippocampus. Likewise, we distinguish between experientially detailed spatial memories (akin to episodic memory) and more schematic memories (akin to semantic memory) that are sufficient for navigation but not for re-experiencing the environment in which they were acquired. Like their episodic and semantic counterparts, the former type of spatial memory is dependent on the hippocampus no matter how long ago it was acquired, whereas the latter can survive independently of the hippocampus and is represented in extra-hippocampal structures. In short, the evidence reviewed suggests strongly that the function of the hippocampus (and possibly that of related limbic structures) is to help encode, retain, and retrieve experiences, no matter how long ago the events comprising the experience occurred, and no matter whether the memories are episodic or spatial. We conclude that the evidence favours a multiple trace theory (MTT) of memory over two other models: (1) traditional consolidation models which posit that the hippocampus is a time-limited memory structure for all forms of memory; and (2) versions of cognitive map theory which posit that the hippocampus is needed for representing all forms of allocentric space in memory.

Forward Association, Backward Association, and the False-Memory Illusion

ERIC Educational Resources Information Center

Brainerd, C. J.; Wright, Ron

2005-01-01

In the Deese-Roediger-McDermott false-memory illusion, forward associative strength (FAS) is unrelated to the strength of the illusion; this is puzzling, because high-FAS lists ought to share more semantic features with critical unpresented words than should low-FAS lists. The authors show that this null result is probably a truncated range…

Acceptability and Feasibility Results of a Strength-Based Skills Training Program for Dementia Caregiving Dyads

ERIC Educational Resources Information Center

Judge, Katherine S.; Yarry, Sarah J.; Orsulic-Jeras, Silvia

2010-01-01

Purpose: The current article provides an in-depth description of a dyadic intervention for individuals with dementia and their family caregivers. Using a strength-based approach, caregiving dyads received skills training across 5 key areas: (a) education regarding dementia and memory loss, (b) effective communication, (c) managing memory loss, (d)…

A Model for Stochastic Drift in Memory Strength to Account for Judgments of Learning

ERIC Educational Resources Information Center

Sikstrom, Sverker; Jonsson, Fredrik

2005-01-01

Previous research has shown that judgments of learning (JOLs) made immediately after encoding have a low correlation with actual cued-recall performance, whereas the correlation is high for delayed judgments. In this article, the authors propose a formal theory describing the stochastic drift of memory strength over the retention interval to…

Neurotoxic lesions of the dorsal and ventral hippocampus impair acquisition and expression of trace-conditioned fear-potentiated startle in rats.

PubMed

Trivedi, Mehul A; Coover, Gary D

2006-04-03

Pavlovian delay conditioning, in which a conditioned stimulus (CS) and unconditioned stimulus (US) co-terminate, is thought to reflect non-declarative memory. In contrast, trace conditioning, in which the CS and US are temporally separate, is thought to reflect declarative memory. Hippocampal lesions impair acquisition and expression of trace conditioning measured by the conditioned freezing and eyeblink responses, while having little effect on the acquisition of delay conditioning. Recent evidence suggests that lesions of the ventral hippocampus (VH) impair conditioned fear under conditions in which dorsal hippocampal (DH) lesions have little effect. In the present study, we examined the time-course of fear expression after delay and trace conditioning using the fear-potentiated startle (FPS) reflex, and the effects of pre- and post-training lesions to the VH and DH on trace-conditioned FPS. We found that both delay- and trace-conditioned rats displayed significant FPS near the end of the CS relative to the unpaired control group. In contrast, trace-conditioned rats displayed significant FPS throughout the duration of the trace interval, whereas FPS decayed rapidly to baseline after CS offset in delay-conditioned rats. In experiment 2, both DH and VH lesions were found to significantly reduce the overall magnitude of FPS compared to the control group, however, no differences were found between the DH and VH groups. These findings support a role for both the DH and VH in trace fear conditioning, and suggest that the greater effect of VH lesions on conditioned fear might be specific to certain measures of fear.

Mechanical analysis of carbon fiber reinforced shape memory polymer composite for self-deployable structure in space environment

NASA Astrophysics Data System (ADS)

Hong, Seok Bin; Ahn, Yong San; Jang, Joon Hyeok; Kim, Jin-Gyun; Goo, Nam Seo; Yu, Woong-Ryeol

2016-04-01

Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Reinforcements as carbon fiber had been used for making shape memory polymer composite (CF-SMPC). This study investigated a possibility of designing self-deployable structures in harsh space condition using CF-SMPCs and analyzed their shape memory behaviors with constitutive equation model.CF-SMPCs were prepared using woven carbon fabrics and a thermoset epoxy based SMP to obtain their basic mechanical properties including actuation in harsh environment. The mechanical and shape memory properties of SMP and CF-SMPCs were characterized using dynamic mechanical analysis (DMA) and universal tensile machine (UTM) with an environmental chamber. The mechanical properties such as flexural strength and tensile strength of SMP and CF-SMPC were measured with simple tensile/bending test and time dependent shape memory behavior was characterized with designed shape memory bending test. For mechanical analysis of CF-SMPCs, a 3D constitutive equation of SMP, which had been developed using multiplicative decomposition of the deformation gradient and shape memory strains, was used with material parameters determined from CF-SMPCs. Carbon fibers in composites reinforced tensile and flexural strength of SMP and acted as strong elastic springs in rheology based equation models. The actuation behavior of SMP matrix and CF-SMPCs was then simulated as 3D shape memory bending cases. Fiber bundle property was imbued with shell model for more precise analysis and it would be used for prediction of deploying behavior in self-deployable hinge structure.

Role of cerebellar cortical protein synthesis in transfer of memory trace of cerebellum-dependent motor learning.

PubMed

Okamoto, Takehito; Endo, Shogo; Shirao, Tomoaki; Nagao, Soichi

2011-06-15

We developed a new protocol that induces long-term adaptation of horizontal optokinetic response (HOKR) eye movement by hours of spaced training and examined the role of protein synthesis in the cerebellar cortex in the formation of memory of adaptation. Mice were trained to view 800 cycles of screen oscillation either by 1 h of massed training or by 2.5 h to 8 d of training with 0.5 h to 1 d space intervals. The HOKR gains increased similarly by 20-30% at the end of training; however, the gains increased by 1 h of massed training recovered within 24 h, whereas the gains increased by spaced training were sustained over 24 h. Bilateral floccular lidocaine microinfusions immediately after the end of training recovered the gains increased by 1 h of massed training but did not affect the gains increased by 4 h of spaced training, suggesting that the memory trace of adaptation was transferred from the flocculus to the vestibular nuclei within 4 h of spaced training. Blockade of floccular protein synthesis, examined by bilateral floccular microinfusions of anisomycin or actinomycin D 1-4 h before the training, impaired the gains increased by 4 h of spaced training but did not affect the gains increased by 1 h of massed training. These findings suggest that the transfer of the memory trace of adaptation occurs within 4 h of spaced training, and proteins synthesized in the flocculus during training period may play an important role in memory transfer.

An adaptive replacement algorithm for paged-memory computer systems.

NASA Technical Reports Server (NTRS)

Thorington, J. M., Jr.; Irwin, J. D.

1972-01-01

A general class of adaptive replacement schemes for use in paged memories is developed. One such algorithm, called SIM, is simulated using a probability model that generates memory traces, and the results of the simulation of this adaptive scheme are compared with those obtained using the best nonlookahead algorithms. A technique for implementing this type of adaptive replacement algorithm with state of the art digital hardware is also presented.

Recognition Decisions From Visual Working Memory Are Mediated by Continuous Latent Strengths.

PubMed

Ricker, Timothy J; Thiele, Jonathan E; Swagman, April R; Rouder, Jeffrey N

2017-08-01

Making recognition decisions often requires us to reference the contents of working memory, the information available for ongoing cognitive processing. As such, understanding how recognition decisions are made when based on the contents of working memory is of critical importance. In this work we examine whether recognition decisions based on the contents of visual working memory follow a continuous decision process of graded information about the correct choice or a discrete decision process reflecting only knowing and guessing. We find a clear pattern in favor of a continuous latent strength model of visual working memory-based decision making, supporting the notion that visual recognition decision processes are impacted by the degree of matching between the contents of working memory and the choices given. Relation to relevant findings and the implications for human information processing more generally are discussed. Copyright © 2016 Cognitive Science Society, Inc.

Memory bias for negative emotional words in recognition memory is driven by effects of category membership

PubMed Central

White, Corey N.; Kapucu, Aycan; Bruno, Davide; Rotello, Caren M.; Ratcliff, Roger

2014-01-01

Recognition memory studies often find that emotional items are more likely than neutral items to be labeled as studied. Previous work suggests this bias is driven by increased memory strength/familiarity for emotional items. We explored strength and bias interpretations of this effect with the conjecture that emotional stimuli might seem more familiar because they share features with studied items from the same category. Categorical effects were manipulated in a recognition task by presenting lists with a small, medium, or large proportion of emotional words. The liberal memory bias for emotional words was only observed when a medium or large proportion of categorized words were presented in the lists. Similar, though weaker, effects were observed with categorized words that were not emotional (animal names). These results suggest that liberal memory bias for emotional items may be largely driven by effects of category membership. PMID:24303902

Memory bias for negative emotional words in recognition memory is driven by effects of category membership.

PubMed

White, Corey N; Kapucu, Aycan; Bruno, Davide; Rotello, Caren M; Ratcliff, Roger

2014-01-01

Recognition memory studies often find that emotional items are more likely than neutral items to be labelled as studied. Previous work suggests this bias is driven by increased memory strength/familiarity for emotional items. We explored strength and bias interpretations of this effect with the conjecture that emotional stimuli might seem more familiar because they share features with studied items from the same category. Categorical effects were manipulated in a recognition task by presenting lists with a small, medium or large proportion of emotional words. The liberal memory bias for emotional words was only observed when a medium or large proportion of categorised words were presented in the lists. Similar, though weaker, effects were observed with categorised words that were not emotional (animal names). These results suggest that liberal memory bias for emotional items may be largely driven by effects of category membership.

Emotion Causes Targeted Forgetting of Established Memories

PubMed Central

Strange, Bryan A.; Kroes, Marijn C. W.; Fan, Judith E.; Dolan, Raymond J.

2010-01-01

Reconsolidation postulates that reactivation of a memory trace renders it susceptible to disruption by treatments similar to those that impair initial memory consolidation. Despite evidence that implicit, or non-declarative, human memories can be disrupted at retrieval, a convincing demonstration of selective impairment in retrieval of target episodic memories following reactivation is lacking. In human subjects, we demonstrate that if reactivation of a verbal memory, through successful retrieval, is immediately followed by an emotionally aversive stimulus, a significant impairment is evident in its later recall. This effect is time-dependent and persists for at least 6 days. Thus, in line with a reconsolidation hypothesis, established human episodic memories can be selectively impaired following their retrieval. PMID:21191439

Emotion causes targeted forgetting of established memories.

PubMed

Strange, Bryan A; Kroes, Marijn C W; Fan, Judith E; Dolan, Raymond J

2010-01-01

Reconsolidation postulates that reactivation of a memory trace renders it susceptible to disruption by treatments similar to those that impair initial memory consolidation. Despite evidence that implicit, or non-declarative, human memories can be disrupted at retrieval, a convincing demonstration of selective impairment in retrieval of target episodic memories following reactivation is lacking. In human subjects, we demonstrate that if reactivation of a verbal memory, through successful retrieval, is immediately followed by an emotionally aversive stimulus, a significant impairment is evident in its later recall. This effect is time-dependent and persists for at least 6 days. Thus, in line with a reconsolidation hypothesis, established human episodic memories can be selectively impaired following their retrieval.

Catching the engram: strategies to examine the memory trace.

PubMed

Sakaguchi, Masanori; Hayashi, Yasunori

2012-09-21

Memories are stored within neuronal ensembles in the brain. Modern genetic techniques can be used to not only visualize specific neuronal ensembles that encode memories (e.g., fear, craving) but also to selectively manipulate those neurons. These techniques are now being expanded for the study of various types of memory. In this review, we will summarize the genetic methods used to visualize and manipulate neurons involved in the representation of memory engrams. The methods will help clarify how memory is encoded, stored and processed in the brain. Furthermore, these approaches may contribute to our understanding of the pathological mechanisms associated with human memory disorders and, ultimately, may aid the development of therapeutic strategies to ameliorate these diseases.

Dentate granule cell recruitment of feedforward inhibition governs engram maintenance and remote memory generalization.

PubMed

Guo, Nannan; Soden, Marta E; Herber, Charlotte; Kim, Michael TaeWoo; Besnard, Antoine; Lin, Paoyan; Ma, Xiang; Cepko, Constance L; Zweifel, Larry S; Sahay, Amar

2018-05-01

Memories become less precise and generalized over time as memory traces reorganize in hippocampal-cortical networks. Increased time-dependent loss of memory precision is characterized by an overgeneralization of fear in individuals with post-traumatic stress disorder (PTSD) or age-related cognitive impairments. In the hippocampal dentate gyrus (DG), memories are thought to be encoded by so-called 'engram-bearing' dentate granule cells (eDGCs). Here we show, using rodents, that contextual fear conditioning increases connectivity between eDGCs and inhibitory interneurons (INs) in the downstream hippocampal CA3 region. We identify actin-binding LIM protein 3 (ABLIM3) as a mossy-fiber-terminal-localized cytoskeletal factor whose levels decrease after learning. Downregulation of ABLIM3 expression in DGCs was sufficient to increase connectivity with CA3 stratum lucidum INs (SLINs), promote parvalbumin (PV)-expressing SLIN activation, enhance feedforward inhibition onto CA3 and maintain a fear memory engram in the DG over time. Furthermore, downregulation of ABLIM3 expression in DGCs conferred conditioned context-specific reactivation of memory traces in hippocampal-cortical and amygdalar networks and decreased fear memory generalization at remote (i.e., distal) time points. Consistent with the observation of age-related hyperactivity of CA3, learning failed to increase DGC-SLIN connectivity in 17-month-old mice, whereas downregulation of ABLIM3 expression was sufficient to restore DGC-SLIN connectivity, increase PV+ SLIN activation and improve the precision of remote memories. These studies exemplify a connectivity-based strategy that targets a molecular brake of feedforward inhibition in DG-CA3 and may be harnessed to decrease time-dependent memory generalization in individuals with PTSD and improve memory precision in aging individuals.

Development of the False-Memory Illusion

ERIC Educational Resources Information Center

Brainerd, C. J.; Forrest, T. J.; Karibian, D.; Reyna, V. F.

2006-01-01

The counterintuitive developmental trend in the Deese-Roediger-McDermott (DRM) illusion (that false-memory responses increase with age) was investigated in learning-disabled and nondisabled children from the 6- to 14-year-old age range. Fuzzy-trace theory predicts that because there are qualitative differences in how younger versus older children…

Effects of Ethanol-Gasoline Blended Fuels on Learning and Memory

EPA Science Inventory

The potential toxicity of ethanol-gasoline blended fuels to the developing nervous system is of concern. We previously reported an absence of effect on learning and memory as seen in a trace fear conditioning task and water maze task in offspring of dams exposed prenatally to the...

Beyond the Archive: Cultural Memory in Dance and Theater

ERIC Educational Resources Information Center

Bernstein, Carol L.

2007-01-01

This essay uses the concept of the constellation to characterize the relations among interdisciplinarity, cultural memory, and comparative literature. To do so entails: (a) reviewing the paradoxical interdisciplinarity of comparative literature, (b) tracing its establishment at a liberal arts college (Bryn Mawr College, USA), and (c) describing a…

Type I Rehearsal and Recognition.

ERIC Educational Resources Information Center

Glenberg, Arthur; Adams, Frederick

1978-01-01

Rote, repetitive Type I Rehearsal is defined as the continuous maintenance of information in memory using the minimum cognitive capacity necessary for maintenance. An analysis of errors made on a forced-choice recognition test supported the hypothesis that acoustic-phonemic components of the memory trace are added or strengthened by this…

Does Tracing Worked Examples Enhance Geometry Learning?

ERIC Educational Resources Information Center

Hu, Fang-Tzu; Ginns, Paul; Bobis, Janette

2014-01-01

Cognitive load theory seeks to generate novel instructional designs through a focus on human cognitive architecture including a limited working memory; however, the potential for enhancing learning through non-visual or non-auditory working memory channels is yet to be evaluated. This exploratory experiment tested whether explicit instructions to…

Effects of Semantic and Orthographic Interference on Prose Recall.

ERIC Educational Resources Information Center

Burton, John K.; And Others

"Levels of processing" is an explanatory framework postulating that differences in memory processing quality or effort affect the duration of the memory trace. Using recall (immediate, one week, or two week) for connected discourse processed under three semantic and three orthographic interference conditions, as well as a noninterference…

Retrieval Does Not Induce Reconsolidation of Inhibitory Avoidance Memory

ERIC Educational Resources Information Center

Medina, Jorge H.; Izquierdo, Ivan; Cammarota, Martin; Bevilaqua, Lia R. M.

2004-01-01

It has been suggested that retrieval during a nonreinforced test induces reconsolidation instead of extinction of the mnemonic trace. Reconsolidation would preserve the original memory from the labilization induced by its nonreinforced recall through a hitherto uncharacterized mechanism requiring protein synthesis. Given the importance that such a…

What Factors Underlie Associative and Categorical Memory Illusions? The Roles of Backward Associative Strength and Interitem Connectivity

ERIC Educational Resources Information Center

Knott, Lauren M.; Dewhurst, Stephen A.; Howe, Mark L.

2012-01-01

Factors that affect categorical and associative false memory illusions were investigated in 2 experiments. In Experiment 1, backward associative strength (BAS) from the list word to the critical lure and interitem connectivity were manipulated in Deese-Roediger-McDermott (DRM) and category list types. For both recall and recognition tasks, the…

'I remember therefore I am, and I am therefore I remember': exploring the contributions of episodic and semantic self-knowledge to strength of identity.

PubMed

Haslam, Catherine; Jetten, Jolanda; Haslam, S Alexander; Pugliese, Cara; Tonks, James

2011-05-01

The present research explores the relationship between the two components of autobiographical memory--episodic and semantic self-knowledge--and identity strength in older adults living in the community and residential care. Participants (N= 32) completed the autobiographical memory interview and measures of personal identity strength and multiple group memberships. Contrary to previous research, autobiographical memory for all time periods (childhood, early adulthood, and recent life) in the semantic domain was associated with greater strength in personal identity. Further, we obtained support for the hypothesis that the relationship between episodic self-knowledge and identity strength would be mediated by knowledge of personal semantic facts. However, there was also support for a reverse mediation model indicating that a strong sense of identity is associated with semantic self-knowledge and through this may enhance self-relevant recollection. The discussion elaborates on these findings and we propose a self-knowledge and identity model (SKIM) whereby semantic self-knowledge mediates a bidirectional relationship between episodic self-knowledge and identity. ©2010 The British Psychological Society.

Sleep Strengthens but does Not Reorganize Memory Traces in a Verbal Creativity Task.

PubMed

Landmann, Nina; Kuhn, Marion; Maier, Jonathan-Gabriel; Feige, Bernd; Spiegelhalder, Kai; Riemann, Dieter; Nissen, Christoph

2016-03-01

Sleep after learning promotes the quantitative strengthening of new memories. Less is known about the impact of sleep on the qualitative reorganization of memory content. This study tested the hypothesis that sleep facilitates both memory strengthening and reorganization as indexed by a verbal creativity task. Sixty healthy university students (30 female, 30 male, 20-30 years) were investigated in a randomized, controlled parallel-group study with three experimental groups (sleep, sleep deprivation, daytime wakefulness). At baseline, 60 items of the Compound Remote Associate (CRA) task were presented. At retest after the experimental conditions, the same items were presented again together with 20 new control items to disentangle off-line incubation from online performance effects. Sleep significantly strengthened formerly encoded memories in comparison to both wake conditions (improvement in speed of correctly resolved items). Offline reorganization was not enhanced following sleep, but was enhanced following sleep-deprivation in comparison to sleep and daytime wakefulness (solution time of previously incubated, newly solved items). Online performance did not differ between the groups (solution time of new control items). The results support the notion that sleep promotes the strengthening, but not the reorganization, of newly encoded memory traces in a verbal creativity task. Future studies are needed to further determine the impact of sleep on different types of memory reorganization, such as associative thinking, creativity and emotional memory processing, and potential clinical translations, such as the augmentation of psychotherapy through sleep interventions. © 2016 Associated Professional Sleep Societies, LLC.

Dreaming and Offline Memory Consolidation

PubMed Central

Wamsley, Erin J.

2015-01-01

Converging evidence suggests that dreaming is influenced by the consolidation of memory during sleep. Following encoding, recently formed memory traces are gradually stabilized and reorganized into a more permanent form of long-term storage. Sleep provides an optimal neurophysiological state to facilitate this process, allowing memory networks to be repeatedly reactivated in the absence of new sensory input. The process of memory reactivation and consolidation in the sleeping brain appears to influence conscious experience during sleep, contributing to dream content recalled on awakening. This article outlines several lines of evidence in support of this hypothesis, and responds to some common objections. PMID:24477388

On initial Brain Activity Mapping of episodic and semantic memory code in the hippocampus.

PubMed

Tsien, Joe Z; Li, Meng; Osan, Remus; Chen, Guifen; Lin, Longian; Wang, Phillip Lei; Frey, Sabine; Frey, Julietta; Zhu, Dajiang; Liu, Tianming; Zhao, Fang; Kuang, Hui

2013-10-01

It has been widely recognized that the understanding of the brain code would require large-scale recording and decoding of brain activity patterns. In 2007 with support from Georgia Research Alliance, we have launched the Brain Decoding Project Initiative with the basic idea which is now similarly advocated by BRAIN project or Brain Activity Map proposal. As the planning of the BRAIN project is currently underway, we share our insights and lessons from our efforts in mapping real-time episodic memory traces in the hippocampus of freely behaving mice. We show that appropriate large-scale statistical methods are essential to decipher and measure real-time memory traces and neural dynamics. We also provide an example of how the carefully designed, sometime thinking-outside-the-box, behavioral paradigms can be highly instrumental to the unraveling of memory-coding cell assembly organizing principle in the hippocampus. Our observations to date have led us to conclude that the specific-to-general categorical and combinatorial feature-coding cell assembly mechanism represents an emergent property for enabling the neural networks to generate and organize not only episodic memory, but also semantic knowledge and imagination. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

On Initial Brain Activity Mapping of Associative Memory Code in the Hippocampus

PubMed Central

Tsien, Joe Z.; Li, Meng; Osan, Remus; Chen, Guifen; Lin, Longian; Lei Wang, Phillip; Frey, Sabine; Frey, Julietta; Zhu, Dajiang; Liu, Tianming; Zhao, Fang; Kuang, Hui

2013-01-01

It has been widely recognized that the understanding of the brain code would require large-scale recording and decoding of brain activity patterns. In 2007 with support from Georgia Research Alliance, we have launched the Brain Decoding Project Initiative with the basic idea which is now similarly advocated by BRAIN project or Brain Activity Map proposal. As the planning of the BRAIN project is currently underway, we share our insights and lessons from our efforts in mapping real-time episodic memory traces in the hippocampus of freely behaving mice. We show that appropriate large-scale statistical methods are essential to decipher and measure real-time memory traces and neural dynamics. We also provide an example of how the carefully designed, sometime thinking-outside-the-box, behavioral paradigms can be highly instrumental to the unraveling of memory-coding cell assembly organizing principle in the hippocampus. Our observations to date have led us to conclude that the specific-to-general categorical and combinatorial feature-coding cell assembly mechanism represents an emergent property for enabling the neural networks to generate and organize not only episodic memory, but also semantic knowledge and imagination. PMID:23838072

Why does lag affect the durability of memory-based automaticity: loss of memory strength or interference?

PubMed

Wilkins, Nicolas J; Rawson, Katherine A

2013-10-01

In Rickard, Lau, and Pashler's (2008) investigation of the lag effect on memory-based automaticity, response times were faster and proportion of trials retrieved was higher at the end of practice for short lag items than for long lag items. However, during testing after a delay, response times were slower and proportion of trials retrieved was lower for short lag items than for long lag items. The current study investigated the extent to which the lag effect on the durability of memory-based automaticity is due to interference or to the loss of memory strength with time. Participants repeatedly practiced alphabet subtraction items in short lag and long lag conditions. After practice, half of the participants were immediately tested and the other half were tested after a 7-day delay. Results indicate that the lag effect on the durability of memory-based automaticity is primarily due to interference. We discuss potential modification of current memory-based processing theories to account for these effects. © 2013.

What is the connection between true and false memories? The differential roles of interitem associations in recall and recognition.

PubMed

McEvoy, C L; Nelson, D L; Komatsu, T

1999-09-01

Veridical memory for presented list words and false memory for nonpresented but related items were tested using the Deese/Roediger and McDermott paradigm. The strength and density of preexisting connections among the list words, and from the list words to the critical items, were manipulated. The likelihood of producing false memories in free recall varied with the strength of connections from the list words to the critical items but was inversely related to the density of the interconnections among the list words. In contrast, veridical recall of list words was positively related to the density of the interconnections. A final recognition test showed that both false and veridical memories were more likely when the list words were more densely interconnected. The results are discussed in terms of an associative model of memory, Processing Implicit and Explicit Representations (PIER 2) that describes the influence of implicitly activated preexisting information on memory performance.

Fatigue of graphite/epoxy /0/90/45/-45/s laminates under dual stress levels

NASA Technical Reports Server (NTRS)

Yang, J. N.; Jones, D. L.

1982-01-01

A model for the prediction of loading sequence effects on the statistical distribution of fatigue life and residual strength in composite materials is generalized and applied to (0/90/45/-45)s graphite/epoxy laminates. Load sequence effects are found to be caused by both the difference in residual strength when failure occurs (boundary effect) and the effect of previously applied loads (memory effect). The model allows the isolation of these two effects, and the estimation of memory effect magnitudes under dual fatigue loading levels. It is shown that the material memory effect is insignificant, and that correlations between predictions of the number of early failures agree with the verification tests, as do predictions of fatigue life and residual strength degradation under dual stress levels.

Developmental dissociation between the maturation of procedural memory and declarative memory.

PubMed

Finn, Amy S; Kalra, Priya B; Goetz, Calvin; Leonard, Julia A; Sheridan, Margaret A; Gabrieli, John D E

2016-02-01

Declarative memory and procedural memory are known to be two fundamentally different kinds of memory that are dissociable in their psychological characteristics and measurement (explicit vs. implicit) and in the neural systems that subserve each kind of memory. Declarative memory abilities are known to improve from childhood through young adulthood, but the developmental maturation of procedural memory is largely unknown. We compared 10-year-old children and young adults on measures of declarative memory and working memory capacity and on four measures of procedural memory that have been strongly dissociated from declarative memory (mirror tracing, rotary pursuit, probabilistic classification, and artificial grammar). Children had lesser declarative memory ability and lesser working memory capacity than adults, but children exhibited learning equivalent to adults on all four measures of procedural memory. Therefore, declarative memory and procedural memory are developmentally dissociable, with procedural memory being adult-like by age 10years and declarative memory continuing to mature into young adulthood. Copyright © 2015 Elsevier Inc. All rights reserved.

The strengths and weaknesses in verbal short-term memory and visual working memory in children with hearing impairment and additional language learning difficulties.

PubMed

Willis, Suzi; Goldbart, Juliet; Stansfield, Jois

2014-07-01

To compare verbal short-term memory and visual working memory abilities of six children with congenital hearing-impairment identified as having significant language learning difficulties with normative data from typically hearing children using standardized memory assessments. Six children with hearing loss aged 8-15 years were assessed on measures of verbal short-term memory (Non-word and word recall) and visual working memory annually over a two year period. All children had cognitive abilities within normal limits and used spoken language as the primary mode of communication. The language assessment scores at the beginning of the study revealed that all six participants exhibited delays of two years or more on standardized assessments of receptive and expressive vocabulary and spoken language. The children with hearing-impairment scores were significantly higher on the non-word recall task than the "real" word recall task. They also exhibited significantly higher scores on visual working memory than those of the age-matched sample from the standardized memory assessment. Each of the six participants in this study displayed the same pattern of strengths and weaknesses in verbal short-term memory and visual working memory despite their very different chronological ages. The children's poor ability to recall single syllable words in relation to non-words is a clinical indicator of their difficulties in verbal short-term memory. However, the children with hearing-impairment do not display generalized processing difficulties and indeed demonstrate strengths in visual working memory. The poor ability to recall words, in combination with difficulties with early word learning may be indicators of children with hearing-impairment who will struggle to develop spoken language equal to that of their normally hearing peers. This early identification has the potential to allow for target specific intervention that may remediate their difficulties. Copyright © 2014. Published by Elsevier Ireland Ltd.

Analysis on applicable error-correcting code strength of storage class memory and NAND flash in hybrid storage

NASA Astrophysics Data System (ADS)

Matsui, Chihiro; Kinoshita, Reika; Takeuchi, Ken

2018-04-01

A hybrid of storage class memory (SCM) and NAND flash is a promising technology for high performance storage. Error correction is inevitable on SCM and NAND flash because their bit error rate (BER) increases with write/erase (W/E) cycles, data retention, and program/read disturb. In addition, scaling and multi-level cell technologies increase BER. However, error-correcting code (ECC) degrades storage performance because of extra memory reading and encoding/decoding time. Therefore, applicable ECC strength of SCM and NAND flash is evaluated independently by fixing ECC strength of one memory in the hybrid storage. As a result, weak BCH ECC with small correctable bit is recommended for the hybrid storage with large SCM capacity because SCM is accessed frequently. In contrast, strong and long-latency LDPC ECC can be applied to NAND flash in the hybrid storage with large SCM capacity because large-capacity SCM improves the storage performance.

The mysteries of remote memory.

PubMed

Albo, Zimbul; Gräff, Johannes

2018-03-19

Long-lasting memories form the basis of our identity as individuals and lie central in shaping future behaviours that guide survival. Surprisingly, however, our current knowledge of how such memories are stored in the brain and retrieved, as well as the dynamics of the circuits involved, remains scarce despite seminal technical and experimental breakthroughs in recent years. Traditionally, it has been proposed that, over time, information initially learnt in the hippocampus is stored in distributed cortical networks. This process-the standard theory of memory consolidation-would stabilize the newly encoded information into a lasting memory, become independent of the hippocampus, and remain essentially unmodifiable throughout the lifetime of the individual. In recent years, several pieces of evidence have started to challenge this view and indicate that long-lasting memories might already ab ovo be encoded, and subsequently stored in distributed cortical networks, akin to the multiple trace theory of memory consolidation. In this review, we summarize these recent findings and attempt to identify the biologically plausible mechanisms based on which a contextual memory becomes remote by integrating different levels of analysis: from neural circuits to cell ensembles across synaptic remodelling and epigenetic modifications. From these studies, remote memory formation and maintenance appear to occur through a multi-trace, dynamic and integrative cellular process ranging from the synapse to the nucleus, and represent an exciting field of research primed to change quickly as new experimental evidence emerges.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'. © 2018 The Authors.

The mysteries of remote memory

PubMed Central

2018-01-01

Long-lasting memories form the basis of our identity as individuals and lie central in shaping future behaviours that guide survival. Surprisingly, however, our current knowledge of how such memories are stored in the brain and retrieved, as well as the dynamics of the circuits involved, remains scarce despite seminal technical and experimental breakthroughs in recent years. Traditionally, it has been proposed that, over time, information initially learnt in the hippocampus is stored in distributed cortical networks. This process—the standard theory of memory consolidation—would stabilize the newly encoded information into a lasting memory, become independent of the hippocampus, and remain essentially unmodifiable throughout the lifetime of the individual. In recent years, several pieces of evidence have started to challenge this view and indicate that long-lasting memories might already ab ovo be encoded, and subsequently stored in distributed cortical networks, akin to the multiple trace theory of memory consolidation. In this review, we summarize these recent findings and attempt to identify the biologically plausible mechanisms based on which a contextual memory becomes remote by integrating different levels of analysis: from neural circuits to cell ensembles across synaptic remodelling and epigenetic modifications. From these studies, remote memory formation and maintenance appear to occur through a multi-trace, dynamic and integrative cellular process ranging from the synapse to the nucleus, and represent an exciting field of research primed to change quickly as new experimental evidence emerges. This article is part of a discussion meeting issue ‘Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists’. PMID:29352028

Retrieval per se is not sufficient to trigger reconsolidation of human fear memory.

PubMed

Sevenster, Dieuwke; Beckers, Tom; Kindt, Merel

2012-03-01

Ample evidence suggests that consolidated memories, upon their retrieval, enter a labile state, in which they might be susceptible to change. It has been proposed that memory labilization allows for the integration of relevant information in the established memory trace (memory updating). Memory labilization and reconsolidation do not necessarily occur when a memory is being reactivated, but only when there is something to be learned during memory retrieval (prediction error). Thus, updating of a fear memory trace should not occur under retrieval conditions in which the outcome is fully predictable (no prediction error). Here, we addressed this issue, using a human differential fear conditioning procedure, by eliminating the very possibility of reinforcement of the reminder cue. A previously established fear memory (picture-shock pairings) was reactivated with shock-electrodes attached (Propranolol group, n=18) or unattached (Propranolol No-Shock Expectation group, n=19). We additionally tested a placebo-control group with the shock-electrodes attached (Placebo group, n=18). Reconsolidation was not triggered when nothing could be learned during the reminder trial, as noradrenergic blockade did not affect expression of the fear memory 24h later in the Propranolol No-Shock Expectation group. Only when the outcome of the retrieval cue was not fully predictable, propranolol, contrary to placebo, reduced the startle fear response and prevented the return of fear (reinstatement) the following day. In line with previous studies, skin conductance response and shock expectancies were not affected by propranolol. Remarkably, a double dissociation emerged between the emotional (startle response) and more cognitive expression (expectancies, SCR) of the fear memory. Our findings have important implications for reconsolidation blockade as treatment strategy for emotional disorders. First, fear reducing procedures that target the emotional component of fear memory do not necessarily affect the cognitive component and vice versa. Second, mere retrieval of the fear memory is not sufficient to induce its labilization and reconsolidation. Copyright © 2012 Elsevier Inc. All rights reserved.

Computational dissection of human episodic memory reveals mental process-specific genetic profiles

PubMed Central

Luksys, Gediminas; Fastenrath, Matthias; Coynel, David; Freytag, Virginie; Gschwind, Leo; Heck, Angela; Jessen, Frank; Maier, Wolfgang; Milnik, Annette; Riedel-Heller, Steffi G.; Scherer, Martin; Spalek, Klara; Vogler, Christian; Wagner, Michael; Wolfsgruber, Steffen; Papassotiropoulos, Andreas; de Quervain, Dominique J.-F.

2015-01-01

Episodic memory performance is the result of distinct mental processes, such as learning, memory maintenance, and emotional modulation of memory strength. Such processes can be effectively dissociated using computational models. Here we performed gene set enrichment analyses of model parameters estimated from the episodic memory performance of 1,765 healthy young adults. We report robust and replicated associations of the amine compound SLC (solute-carrier) transporters gene set with the learning rate, of the collagen formation and transmembrane receptor protein tyrosine kinase activity gene sets with the modulation of memory strength by negative emotional arousal, and of the L1 cell adhesion molecule (L1CAM) interactions gene set with the repetition-based memory improvement. Furthermore, in a large functional MRI sample of 795 subjects we found that the association between L1CAM interactions and memory maintenance revealed large clusters of differences in brain activity in frontal cortical areas. Our findings provide converging evidence that distinct genetic profiles underlie specific mental processes of human episodic memory. They also provide empirical support to previous theoretical and neurobiological studies linking specific neuromodulators to the learning rate and linking neural cell adhesion molecules to memory maintenance. Furthermore, our study suggests additional memory-related genetic pathways, which may contribute to a better understanding of the neurobiology of human memory. PMID:26261317

Computational dissection of human episodic memory reveals mental process-specific genetic profiles.

PubMed

Luksys, Gediminas; Fastenrath, Matthias; Coynel, David; Freytag, Virginie; Gschwind, Leo; Heck, Angela; Jessen, Frank; Maier, Wolfgang; Milnik, Annette; Riedel-Heller, Steffi G; Scherer, Martin; Spalek, Klara; Vogler, Christian; Wagner, Michael; Wolfsgruber, Steffen; Papassotiropoulos, Andreas; de Quervain, Dominique J-F

2015-09-01

Episodic memory performance is the result of distinct mental processes, such as learning, memory maintenance, and emotional modulation of memory strength. Such processes can be effectively dissociated using computational models. Here we performed gene set enrichment analyses of model parameters estimated from the episodic memory performance of 1,765 healthy young adults. We report robust and replicated associations of the amine compound SLC (solute-carrier) transporters gene set with the learning rate, of the collagen formation and transmembrane receptor protein tyrosine kinase activity gene sets with the modulation of memory strength by negative emotional arousal, and of the L1 cell adhesion molecule (L1CAM) interactions gene set with the repetition-based memory improvement. Furthermore, in a large functional MRI sample of 795 subjects we found that the association between L1CAM interactions and memory maintenance revealed large clusters of differences in brain activity in frontal cortical areas. Our findings provide converging evidence that distinct genetic profiles underlie specific mental processes of human episodic memory. They also provide empirical support to previous theoretical and neurobiological studies linking specific neuromodulators to the learning rate and linking neural cell adhesion molecules to memory maintenance. Furthermore, our study suggests additional memory-related genetic pathways, which may contribute to a better understanding of the neurobiology of human memory.

Refreshing memory traces: thinking of an item improves retrieval from visual working memory.

PubMed

Souza, Alessandra S; Rerko, Laura; Oberauer, Klaus

2015-03-01

This article provides evidence that refreshing, a hypothetical attention-based process operating in working memory (WM), improves the accessibility of visual representations for recall. "Thinking of", one of several concurrently active representations, is assumed to refresh its trace in WM, protecting the representation from being forgotten. The link between refreshing and WM performance, however, has only been tenuously supported by empirical evidence. Here, we controlled which and how often individual items were refreshed in a color reconstruction task by presenting cues prompting participants to think of specific WM items during the retention interval. We show that the frequency with which an item is refreshed improves recall of this item from visual WM. Our study establishes a role of refreshing in recall from visual WM and provides a new method for studying the impact of refreshing on the amount of information we can keep accessible for ongoing cognition. © 2014 New York Academy of Sciences.

Reminder duration determines threat memory modification in humans.

PubMed

Hu, Jingchu; Wang, Wenqing; Homan, Philipp; Wang, Penggui; Zheng, Xifu; Schiller, Daniela

2018-06-11

Memory reminders can return a memory into an unstable state such that it will decay unless actively restabilized into long-term memory through reconsolidation. Exposure to a memory reminder, however, does not always lead to destabilization. The 'trace dominance' principle posits that the extent of exposure to memory reminders governs memory susceptibility to disruption. Here, we provide a first systematic investigation of reminder duration effects on threat memory modification in humans. Reminder duration was parametrically varied across 155 participants in a three-day protocol. We found that short reminders (1 s and 4 s) made the memory prone to interference from post-retrieval extinction, suggesting that the memory had been updated. In contrast, no reminder or long reminders (30 s and 3 min) made the memory resistant to such interference, and robustly return. Reminder duration therefore influences memory stability and may be a critical determinant of therapeutic efficacy.

Influence of Thin-Film Adhesives in Pullout Tests Between Nickel-Titanium Shape Memory Alloy and Carbon Fiber-Reinforced Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Quade, Derek J.; Jana, Sadhan; McCorkle, Linda S.

2018-01-01

Strips of nickel-titanium (NiTi) shape memory alloy (SMA) and carbon fiber-reinforced polymer matrix composite (PMC) were bonded together using multiple thin film adhesives and their mechanical strengths were evaluated under pullout test configuration. Tensile and lap shear tests were conducted to confirm the deformation of SMAs at room temperature and to evaluate the adhesive strength between the NiTi strips and the PMC. Optical and scanning electron microscopy techniques were used to examine the interfacial bonding after failure. Simple equations on composite tensile elongation were used to fit the experimental data on tensile properties. ABAQUS models were generated to show the effects of enhanced bond strength and the distribution of stress in SMA and PMC. The results revealed that the addition of thin film adhesives increased the average adhesive strength between SMA and PMC while halting the room temperature shape memory effect within the pullout specimen.

Multi-range force sensors utilizing shape memory alloys

DOEpatents

Varma, Venugopal K.

2003-04-15

The present invention provides a multi-range force sensor comprising a load cell made of a shape memory alloy, a strain sensing system, a temperature modulating system, and a temperature monitoring system. The ability of the force sensor to measure contact forces in multiple ranges is effected by the change in temperature of the shape memory alloy. The heating and cooling system functions to place the shape memory alloy of the load cell in either a low temperature, low strength phase for measuring small contact forces, or a high temperature, high strength phase for measuring large contact forces. Once the load cell is in the desired phase, the strain sensing system is utilized to obtain the applied contact force. The temperature monitoring system is utilized to ensure that the shape memory alloy is in one phase or the other.

Visual Memories Bypass Normalization.

PubMed

Bloem, Ilona M; Watanabe, Yurika L; Kibbe, Melissa M; Ling, Sam

2018-05-01

How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

Visual Memories Bypass Normalization

PubMed Central

Bloem, Ilona M.; Watanabe, Yurika L.; Kibbe, Melissa M.; Ling, Sam

2018-01-01

How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores—neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation. PMID:29596038

Encoding-related brain activity and accelerated forgetting in transient epileptic amnesia.

PubMed

Atherton, Kathryn E; Filippini, Nicola; Zeman, Adam Z J; Nobre, Anna C; Butler, Christopher R

2018-05-17

The accelerated forgetting of newly learned information is common amongst patients with epilepsy and, in particular, in the syndrome of transient epileptic amnesia (TEA). However, the neural mechanisms underlying accelerated forgetting are poorly understood. It has been hypothesised that interictal epileptiform activity during longer retention intervals disrupts normally established memory traces. Here, we tested a distinct hypothesis-that accelerated forgetting relates to the abnormal encoding of memories. We studied a group of 15 patients with TEA together with matched, healthy control subjects. Despite normal performance on standard anterograde memory tasks, patients showed accelerated forgetting of a word list over one week. We used a subsequent memory paradigm to compare encoding-related brain activity in patients and controls. Participants studied a series of visually presented scenes whilst undergoing functional MRI scanning. Recognition memory for these scenes was then probed outside the scanner after delays of 45 min and of 4 days. Patients showed poorer memory for the scenes compared with controls. In the patients but not the controls, subsequently forgotten stimuli were associated with reduced hippocampal activation at encoding. Furthermore, patients demonstrated reduced deactivation of posteromedial cortex regions upon viewing subsequently remembered stimuli as compared to subsequently forgotten ones. These data suggest that abnormal encoding-related activity in key memory areas of the brain contributes to accelerated forgetting in TEA. We propose that abnormally encoded memory traces may be particularly vulnerable to interference from subsequently encountered material and hence be forgotten more rapidly. Our results shed light on the mechanisms underlying memory impairment in epilepsy, and offer support to the proposal that accelerated forgetting may be a useful marker of subtle dysfunction in memory-related brain systems. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

CRTC1 Nuclear Translocation Following Learning Modulates Memory Strength via Exchange of Chromatin Remodeling Complexes on the Fgf1 Gene.

PubMed

Uchida, Shusaku; Teubner, Brett J W; Hevi, Charles; Hara, Kumiko; Kobayashi, Ayumi; Dave, Rutu M; Shintaku, Tatsushi; Jaikhan, Pattaporn; Yamagata, Hirotaka; Suzuki, Takayoshi; Watanabe, Yoshifumi; Zakharenko, Stanislav S; Shumyatsky, Gleb P

2017-01-10

Memory is formed by synapse-to-nucleus communication that leads to regulation of gene transcription, but the identity and organizational logic of signaling pathways involved in this communication remain unclear. Here we find that the transcription cofactor CRTC1 is a critical determinant of sustained gene transcription and memory strength in the hippocampus. Following associative learning, synaptically localized CRTC1 is translocated to the nucleus and regulates Fgf1b transcription in an activity-dependent manner. After both weak and strong training, the HDAC3-N-CoR corepressor complex leaves the Fgf1b promoter and a complex involving the translocated CRTC1, phosphorylated CREB, and histone acetyltransferase CBP induces transient transcription. Strong training later substitutes KAT5 for CBP, a process that is dependent on CRTC1, but not on CREB phosphorylation. This in turn leads to long-lasting Fgf1b transcription and memory enhancement. Thus, memory strength relies on activity-dependent changes in chromatin and temporal regulation of gene transcription on specific CREB/CRTC1 gene targets. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Dopaminergic Modulation of the Persistence of One-Trial Hippocampus-Dependent Memory

ERIC Educational Resources Information Center

O'Carroll, Colin M.; Martin, Stephen J.; Sandin, Johan; Frenguelli, Bruno; Morris, Richard G. M.

2006-01-01

The persistence of new memory traces in the hippocampus, encoded following appropriate activation of glutamatergic receptors and the induction of synaptic plasticity, can be influenced by heterosynaptic activation of neuromodulatory brain systems. We therefore investigated the effects of a hippocampus-specific blockade of dopamine D1/D5 receptors…

The Effect of Guided Imagery and Internal Visualization on Learning

DTIC Science & Technology

1987-01-01

existance) of - . memory traces, and how retrival cues operate, to name a few. The lack of a single theory or a coherent approach has not deterred movement...and function (Subtask 3) to a 31% gain over the control group for information emphasizing the rote memory of sequential data (Subtask 1). Overall, the

Writing Childhoods, Righting Memory: Intergenerational Remembrance in Post-Communist Romania

ERIC Educational Resources Information Center

Pohrib, Codruta Alina

2016-01-01

This article traces different appropriations of intergenerational memory in post-communist Romania in three non-formal educational texts: the pop-up book "The Golden Age for Children"; "?n fata blocului" (Outside the apartment building), a collection of outdoor games that defined the generations of the 1970s and 1980s; and…

Regulative Discourses of Primary Schooling in Greece: Memories of Punishment

ERIC Educational Resources Information Center

Asimaki, Anna; Koustourakis, Gerasimos; Vergidis, Dimitris

2016-01-01

The mechanisms of discipline and power within the institution of the school constitute, in part, the relationship between society and childhood. This article traces the relationship between official regulative discourses of control and punishment practices over students in primary school. It focuses on the memories of schooling of first-year…

Prediction Error and Trace Dominance Determine the Fate of Fear Memories after Post-Training Manipulations

ERIC Educational Resources Information Center

Alfei, Joaquín M.; Monti, Roque I. Ferrer; Molina, Victor A.; Bueno, Adrián M.; Urcelay, Gonzalo P.

2015-01-01

Different mnemonic outcomes have been observed when associative memories are reactivated by CS exposure and followed by amnestics. These outcomes include mere retrieval, destabilization-reconsolidation, a transitional period (which is insensitive to amnestics), and extinction learning. However, little is known about the interaction between initial…

Individual Differences in Depth and Breadth of Processing.

ERIC Educational Resources Information Center

Schmeck, Ronald R.; McCarthy, Patricia

Memory has been defined as traces left behind by past information processing. One approach to the study of everyday memory is to isolate reliable differences between individuals in the ways in which they process information when preparing for test events. The Inventory of Learning Processes, consisting of four scales, i.e., Deep Processing,…

Asymptotic Learning of Alphanumeric Coding in Autobiographical Memory

ERIC Educational Resources Information Center

Martin, Maryanne; Jones, Gregory V.

2007-01-01

Studies of autobiographical memory have shown that observed levels of incidental learning are often relatively low. Do low levels of retention result simply from a low learning rate, or is learning also asymptotic? To address this question, it is necessary to trace performance over a large number of learning opportunities, and this was carried out…

Rapid and automatic speech-specific learning mechanism in human neocortex.

PubMed

Kimppa, Lilli; Kujala, Teija; Leminen, Alina; Vainio, Martti; Shtyrov, Yury

2015-09-01

A unique feature of human communication system is our ability to rapidly acquire new words and build large vocabularies. However, its neurobiological foundations remain largely unknown. In an electrophysiological study optimally designed to probe this rapid formation of new word memory circuits, we employed acoustically controlled novel word-forms incorporating native and non-native speech sounds, while manipulating the subjects' attention on the input. We found a robust index of neurolexical memory-trace formation: a rapid enhancement of the brain's activation elicited by novel words during a short (~30min) perceptual exposure, underpinned by fronto-temporal cortical networks, and, importantly, correlated with behavioural learning outcomes. Crucially, this neural memory trace build-up took place regardless of focused attention on the input or any pre-existing or learnt semantics. Furthermore, it was found only for stimuli with native-language phonology, but not for acoustically closely matching non-native words. These findings demonstrate a specialised cortical mechanism for rapid, automatic and phonology-dependent formation of neural word memory circuits. Copyright © 2015. Published by Elsevier Inc.

A Mismatch-Based Model for Memory Reconsolidation and Extinction in Attractor Networks

PubMed Central

Amaral, Olavo B.

2011-01-01

The processes of memory reconsolidation and extinction have received increasing attention in recent experimental research, as their potential clinical applications begin to be uncovered. A number of studies suggest that amnestic drugs injected after reexposure to a learning context can disrupt either of the two processes, depending on the behavioral protocol employed. Hypothesizing that reconsolidation represents updating of a memory trace in the hippocampus, while extinction represents formation of a new trace, we have built a neural network model in which either simple retrieval, reconsolidation or extinction of a stored attractor can occur upon contextual reexposure, depending on the similarity between the representations of the original learning and reexposure sessions. This is achieved by assuming that independent mechanisms mediate Hebbian-like synaptic strengthening and mismatch-driven labilization of synaptic changes, with protein synthesis inhibition preferentially affecting the former. Our framework provides a unified mechanistic explanation for experimental data showing (a) the effect of reexposure duration on the occurrence of reconsolidation or extinction and (b) the requirement of memory updating during reexposure to drive reconsolidation. PMID:21826231

Impaired Visuospatial Short-Term Memory in Children with ADHD.

PubMed

Narimoto, Tadamasa; Matsuura, Naomi; Hiratani, Michio

2018-01-01

Previous studies provide clear evidence that visuospatial memory performance in children with attention-deficit/hyperactivity disorder (ADHD) is significantly lower than in typically developing children. In the present study, we investigated a major cause of their low performance using a spatial span test. Possibly, inattention resulting from lack of motivation or interest causes their low performance so that they do not correctly encode targets to be remembered. On the other hand, a deficit in temporary maintenance per se may cause their low performance; that is, their inefficient use of rehearsal during a retention interval may lead to memory traces' fast decay. Results in this study indicated that children with ADHD could sustain attention during the encoding phase. Furthermore, their performance at delayed recall was significantly lower than immediate recall, but delayed recall did not affect typically developing children's performance. These results provide evidence for the likelihood that a factor causing children with ADHD difficulty in temporarily maintaining visuospatial information is fast decay of memory traces as a result of inefficient use of rehearsal, not inattention in the encoding phase.

Integrating Cache Performance Modeling and Tuning Support in Parallelization Tools

NASA Technical Reports Server (NTRS)

Waheed, Abdul; Yan, Jerry; Saini, Subhash (Technical Monitor)

1998-01-01

With the resurgence of distributed shared memory (DSM) systems based on cache-coherent Non Uniform Memory Access (ccNUMA) architectures and increasing disparity between memory and processors speeds, data locality overheads are becoming the greatest bottlenecks in the way of realizing potential high performance of these systems. While parallelization tools and compilers facilitate the users in porting their sequential applications to a DSM system, a lot of time and effort is needed to tune the memory performance of these applications to achieve reasonable speedup. In this paper, we show that integrating cache performance modeling and tuning support within a parallelization environment can alleviate this problem. The Cache Performance Modeling and Prediction Tool (CPMP), employs trace-driven simulation techniques without the overhead of generating and managing detailed address traces. CPMP predicts the cache performance impact of source code level "what-if" modifications in a program to assist a user in the tuning process. CPMP is built on top of a customized version of the Computer Aided Parallelization Tools (CAPTools) environment. Finally, we demonstrate how CPMP can be applied to tune a real Computational Fluid Dynamics (CFD) application.

Catching the engram: strategies to examine the memory trace

PubMed Central

2012-01-01

Memories are stored within neuronal ensembles in the brain. Modern genetic techniques can be used to not only visualize specific neuronal ensembles that encode memories (e.g., fear, craving) but also to selectively manipulate those neurons. These techniques are now being expanded for the study of various types of memory. In this review, we will summarize the genetic methods used to visualize and manipulate neurons involved in the representation of memory engrams. The methods will help clarify how memory is encoded, stored and processed in the brain. Furthermore, these approaches may contribute to our understanding of the pathological mechanisms associated with human memory disorders and, ultimately, may aid the development of therapeutic strategies to ameliorate these diseases. PMID:22999350

Sleeping brain, learning brain. The role of sleep for memory systems.

PubMed

Peigneux, P; Laureys, S; Delbeuck, X; Maquet, P

2001-12-21

The hypothesis that sleep participates in the consolidation of recent memory traces has been investigated using four main paradigms: (1) effects of post-training sleep deprivation on memory consolidation, (2) effects of learning on post-training sleep, (3) effects of within sleep stimulation on the sleep pattern and on overnight memories, and (4) re-expression of behavior-specific neural patterns during post-training sleep. These studies convincingly support the idea that sleep is deeply involved in memory functions in humans and animals. However, the available data still remain too scarce to confirm or reject unequivocally the recently upheld hypothesis that consolidations of non-declarative and declarative memories are respectively dependent upon REM and NREM sleep processes.

Forensic Excavation of Rock Masses: A Technique to Investigate Discontinuity Persistence

NASA Astrophysics Data System (ADS)

Shang, J.; Hencher, S. R.; West, L. J.; Handley, K.

2017-11-01

True persistence of rock discontinuities (areas with insignificant tensile strength) is an important factor controlling the engineering behaviour of fractured rock masses, but is extremely difficult to quantify using current geological survey methodologies, even where there is good rock exposure. Trace length as measured in the field or using remote measurement devices is actually only broadly indicative of persistence for rock engineering practice and numerical modelling. Visible traces of discontinuities are treated as if they were open fractures within rock mass classifications, despite many such traces being non-persistent and actually retaining considerable strength. The common assumption of 100% persistence, based on trace length, is generally extremely conservative in terms of strength and stiffness, but not always so and may lead to a wrong prediction of failure mechanism or of excavatability. Assuming full persistence would give hopelessly incorrect predictions of hydraulic conductivity. A new technique termed forensic excavation of rock masses is introduced, as a procedure for directly investigating discontinuity persistence. This technique involves non-explosive excavation of rock masses by injecting an expansive chemical splitter along incipient discontinuities. On expansion, the splitter causes the incipient traces to open as true joints. Experiments are described in which near-planar rock discontinuities, through siltstone and sandstone, were opened up by injecting the splitter into holes drilled along the lines of visible traces of the discontinuities in the laboratory and in the field. Once exposed the surfaces were examined to investigate the pre-existing persistence characteristics of the incipient discontinuities. One conclusion from this study is that visible trace length of a discontinuity can be a poor indicator of true persistence (defined for a fracture area with negligible tensile strength). An observation from this series of experiments was that freshly failed surfaces through pre-existing rock bridges were relatively rough compared to sections of pre-existing weaker areas of geologically developed (though still incipient) discontinuities. Fractographic features such as hackle and rib marks were typical of the freshly broken rock bridges, whereas opened-up areas of incipient discontinuity were smoother. Schmidt hammer rebound values were generally higher for the rock bridge areas, probably reflecting their lower degree of chemical and physical weathering.

The neurobiological bases of memory formation: from physiological conditions to psychopathology.

PubMed

Bisaz, Reto; Travaglia, Alessio; Alberini, Cristina M

2014-01-01

The formation of long-term memories is a function necessary for an adaptive survival. In the last two decades, great progress has been made in the understanding of the biological bases of memory formation. The identification of mechanisms necessary for memory consolidation and reconsolidation, the processes by which the posttraining and postretrieval fragile memory traces become stronger and insensitive to disruption, has indicated new approaches for investigating and treating psychopathologies. In this review, we will discuss some key biological mechanisms found to be critical for memory consolidation and strengthening, the role/s and mechanisms of memory reconsolidation, and how the interference with consolidation and/or reconsolidation can modulate the retention and/or storage of memories that are linked to psychopathologies. © 2014 S. Karger AG, Basel.

Bidirectional Modulation of Alcohol-Associated Memory Reconsolidation through Manipulation of Adrenergic Signaling

PubMed Central

Schramm, Moritz J W; Everitt, Barry J; Milton, Amy L

2016-01-01

Alcohol addiction is a problem of great societal concern, for which there is scope to improve current treatments. One potential new treatment for alcohol addiction is based on disrupting the reconsolidation of the maladaptive Pavlovian memories that can precipitate relapse to drug-seeking behavior. In alcohol self-administering rats, we investigated the effects of bidirectionally modulating adrenergic signaling on the strength of a Pavlovian cue-alcohol memory, using a behavioral procedure that isolates the specific contribution of one maladaptive Pavlovian memory to relapse, the acquisition of a new alcohol-seeking response for an alcohol-associated conditioned reinforcer. The β-adrenergic receptor antagonist propranolol, administered in conjunction with memory reactivation, persistently disrupted the memory that underlies the capacity of a previously alcohol-associated cue to act as a conditioned reinforcer. By contrast, enhancement of adrenergic signaling by administration of the adrenergic prodrug dipivefrin at reactivation increased the strength of the cue-alcohol memory and potentiated alcohol seeking. These data demonstrate the importance of adrenergic signaling in alcohol-associated memory reconsolidation, and suggest a pharmacological target for treatments aiming to prevent relapse through the disruption of maladaptive memories. PMID:26279079

Epigenetic mechanisms and memory strength: a comparative study.

PubMed

Federman, Noel; Zalcman, Gisela; de la Fuente, Verónica; Fustiñana, Maria Sol; Romano, Arturo

2014-01-01

Memory consolidation requires de novo mRNA and protein synthesis. Transcriptional activation is controlled by transcription factors, their cofactors and repressors. Cofactors and repressors regulate gene expression by interacting with basal transcription machinery, remodeling chromatin structure and/or chemically modifying histones. Acetylation is the most studied epigenetic mechanism of histones modifications related to gene expression. This process is regulated by histone acetylases (HATs) and histone deacetylases (HDACs). More than 5 years ago, we began a line of research about the role of histone acetylation during memory consolidation. Here we review our work, presenting evidence about the critical role of this epigenetic mechanism during consolidation of context-signal memory in the crab Neohelice granulata, as well as during consolidation of novel object recognition memory in the mouse Mus musculus. Our evidence demonstrates that histone acetylation is a key mechanism in memory consolidation, functioning as a distinctive molecular feature of strong memories. Furthermore, we found that the strength of a memory can be characterized by its persistence or its resistance to extinction. Besides, we found that the role of this epigenetic mechanism regulating gene expression only in the formation of strongest memories is evolutionarily conserved. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interpretation of Trace Gas Data Using Inverse Methods and Global Chemical Transport Models

NASA Technical Reports Server (NTRS)

Prinn, Ronald G.

1997-01-01

This is a theoretical research project aimed at: (1) development, testing, and refining of inverse methods for determining regional and global transient source and sink strengths for long lived gases important in ozone depletion and climate forcing, (2) utilization of inverse methods to determine these source/sink strengths which use the NCAR/Boulder CCM2-T42 3-D model and a global 3-D Model for Atmospheric Transport and Chemistry (MATCH) which is based on analyzed observed wind fields (developed in collaboration by MIT and NCAR/Boulder), (3) determination of global (and perhaps regional) average hydroxyl radical concentrations using inverse methods with multiple titrating gases, and, (4) computation of the lifetimes and spatially resolved destruction rates of trace gases using 3-D models. Important goals include determination of regional source strengths of methane, nitrous oxide, and other climatically and chemically important biogenic trace gases and also of halocarbons restricted by the Montreal Protocol and its follow-on agreements and hydrohalocarbons used as alternatives to the restricted halocarbons.

Vascular Cognitive Impairment in a Memory Clinic Population: Rationale and Design of the "Utrecht-Amsterdam Clinical Features and Prognosis in Vascular Cognitive Impairment" (TRACE-VCI) Study.

PubMed

Boomsma, Jooske Marije Funke; Exalto, Lieza Geertje; Barkhof, Frederik; van den Berg, Esther; de Bresser, Jeroen; Heinen, Rutger; Koek, Huiberdina Lena; Prins, Niels Daniël; Scheltens, Philip; Weinstein, Henry Chanoch; van der Flier, Wiesje Maria; Biessels, Geert Jan

2017-04-19

Vascular Cognitive Impairment (VCI) refers to cognitive dysfunction due to vascular brain injury, as a single cause or in combination with other, often neurodegenerative, etiologies. VCI is a broad construct that captures a heterogeneous patient population both in terms of cognitive and noncognitive symptoms and in terms of etiology and prognosis. This provides a challenge when applying this construct in clinical practice. This paper presents the rationale and design of the TRACE-VCI study, which investigates the clinical features and prognosis of VCI in a memory clinic setting. The TRACE-VCI project is an observational, prospective cohort study of 861 consecutive memory clinic patients with possible VCI. Between 2009 and 2013, patients were recruited through the Amsterdam Dementia Cohort of the VU University Medical Centre (VUMC) (N=665) and the outpatient memory clinic and VCI cohort of the University Medical Centre Utrecht (UMCU) (N=196). We included all patients attending the clinics with magnetic resonance imaging (MRI) evidence of vascular brain injury. Patients with a primary etiology other than vascular brain injury or neurodegeneration were excluded. Patients underwent an extensive 1-day memory clinic evaluation including an interview, physical and neurological examination, assessment of biomarkers (including those for Alzheimer-type pathologies), extensive neuropsychological testing, and an MRI scan of the brain. For prognostic analyses, the composite primary outcome measure was defined as accelerated cognitive decline (change of clinical dementia rating ≥1 or institutionalization) or (recurrent) major vascular events or death over the course of 2 years. The mean age at baseline was 67.7 (SD 8.5) years and 46.3% of patients (399/861) were female. At baseline, the median Clinical Dementia Rating was 0.5 (interquartile range [IQR] 0.5-1.0) and the median Mini-Mental State Examination score was 25 (IQR 22-28). The clinical diagnosis at baseline was dementia in 52.4% of patients (451/861), mild cognitive impairment in 24.6% (212/861), and no objective cognitive impairment in the remaining 23.0% (198/861). The TRACE-VCI study represents a large cohort of well-characterized patients with VCI in a memory clinic setting. Data processing and collection for follow-up are currently being completed. The TRACE-VCI study will provide insight into the clinical features of memory clinic patients that meet VCI criteria and establish key prognostic factors for further cognitive decline and (recurrent) major vascular events. ©Jooske Marije Funke Boomsma, Lieza Geertje Exalto, Frederik Barkhof, Esther van den Berg, Jeroen de Bresser, Rutger Heinen, Huiberdina Lena Koek, Niels Daniël Prins, Philip Scheltens, Henry Chanoch Weinstein, Wiesje Maria van der Flier, Geert Jan Biessels. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 19.04.2017.

Performance analysis and comparison of a minimum interconnections direct storage model with traditional neural bidirectional memories.

PubMed

Bhatti, A Aziz

2009-12-01

This study proposes an efficient and improved model of a direct storage bidirectional memory, improved bidirectional associative memory (IBAM), and emphasises the use of nanotechnology for efficient implementation of such large-scale neural network structures at a considerable lower cost reduced complexity, and less area required for implementation. This memory model directly stores the X and Y associated sets of M bipolar binary vectors in the form of (MxN(x)) and (MxN(y)) memory matrices, requires O(N) or about 30% of interconnections with weight strength ranging between +/-1, and is computationally very efficient as compared to sequential, intraconnected and other bidirectional associative memory (BAM) models of outer-product type that require O(N(2)) complex interconnections with weight strength ranging between +/-M. It is shown that it is functionally equivalent to and possesses all attributes of a BAM of outer-product type, and yet it is simple and robust in structure, very large scale integration (VLSI), optical and nanotechnology realisable, modular and expandable neural network bidirectional associative memory model in which the addition or deletion of a pair of vectors does not require changes in the strength of interconnections of the entire memory matrix. The analysis of retrieval process, signal-to-noise ratio, storage capacity and stability of the proposed model as well as of the traditional BAM has been carried out. Constraints on and characteristics of unipolar and bipolar binaries for improved storage and retrieval are discussed. The simulation results show that it has log(e) N times higher storage capacity, superior performance, faster convergence and retrieval time, when compared to traditional sequential and intraconnected bidirectional memories.

Overlapping memory trace indispensable for linking, but not recalling, individual memories.

PubMed

Yokose, Jun; Okubo-Suzuki, Reiko; Nomoto, Masanori; Ohkawa, Noriaki; Nishizono, Hirofumi; Suzuki, Akinobu; Matsuo, Mina; Tsujimura, Shuhei; Takahashi, Yukari; Nagase, Masashi; Watabe, Ayako M; Sasahara, Masakiyo; Kato, Fusao; Inokuchi, Kaoru

2017-01-27

Memories are not stored in isolation from other memories but are integrated into associative networks. However, the mechanisms underlying memory association remain elusive. Using two amygdala-dependent behavioral paradigms-conditioned taste aversion (CTA) and auditory-cued fear conditioning (AFC)-in mice, we found that presenting the conditioned stimulus used for the CTA task triggered the conditioned response of the AFC task after natural coreactivation of the memories. This was accompanied through an increase in the overlapping neuronal ensemble in the basolateral amygdala. Silencing of the overlapping ensemble suppressed CTA retrieval-induced freezing. However, retrieval of the original CTA or AFC memory was not affected. A small population of coshared neurons thus mediates the link between memories. They are not necessary for recalling individual memories. Copyright © 2017, American Association for the Advancement of Science.

Short term memory may be the depletion of the readily releasable pool of presynaptic neurotransmitter vesicles of a metastable long term memory trace pattern.

PubMed

Tarnow, Eugen

2009-09-01

The Tagging/Retagging model of short term memory was introduced earlier (Tarnow in Cogn Neurodyn 2(4):347-353, 2008) to explain the linear relationship between response time and correct response probability for word recall and recognition: At the initial stimulus presentation the words displayed tag the corresponding long term memory locations. The tagging process is linear in time and takes about one second to reach a tagging level of 100%. After stimulus presentation the tagging level decays logarithmically with time to 50% after 14 s and to 20% after 220 s. If a probe word is reintroduced the tagging level has to return to 100% for the word to be properly identified, which leads to a delay in response time. This delay is proportional to the tagging loss. The tagging level is directly related to the probability of correct word recall and recognition. Evidence presented suggests that the tagging level is the level of depletion of the Readily Releasable Pool (RRP) of neurotransmitter vesicles at presynaptic terminals. The evidence includes the initial linear relationship between tagging level and time as well as the subsequent logarithmic decay of the tagging level. The activation of a short term memory may thus be the depletion of RRP (exocytosis) and short term memory decay may be the ensuing recycling of the neurotransmitter vesicles (endocytosis). The pattern of depleted presynaptic terminals corresponds to the long term memory trace.

The relationship between level of processing and hippocampal-cortical functional connectivity during episodic memory formation in humans.

PubMed

Schott, Björn H; Wüstenberg, Torsten; Wimber, Maria; Fenker, Daniela B; Zierhut, Kathrin C; Seidenbecher, Constanze I; Heinze, Hans-Jochen; Walter, Henrik; Düzel, Emrah; Richardson-Klavehn, Alan

2013-02-01

New episodic memory traces represent a record of the ongoing neocortical processing engaged during memory formation (encoding). Thus, during encoding, deep (semantic) processing typically establishes more distinctive and retrievable memory traces than does shallow (perceptual) processing, as assessed by later episodic memory tests. By contrast, the hippocampus appears to play a processing-independent role in encoding, because hippocampal lesions impair encoding regardless of level of processing. Here, we clarified the neural relationship between processing and encoding by examining hippocampal-cortical connectivity during deep and shallow encoding. Participants studied words during functional magnetic resonance imaging and freely recalled these words after distraction. Deep study processing led to better recall than shallow study processing. For both levels of processing, successful encoding elicited activations of bilateral hippocampus and left prefrontal cortex, and increased functional connectivity between left hippocampus and bilateral medial prefrontal, cingulate and extrastriate cortices. Successful encoding during deep processing was additionally associated with increased functional connectivity between left hippocampus and bilateral ventrolateral prefrontal cortex and right temporoparietal junction. In the shallow encoding condition, on the other hand, pronounced functional connectivity increases were observed between the right hippocampus and the frontoparietal attention network activated during shallow study processing. Our results further specify how the hippocampus coordinates recording of ongoing neocortical activity into long-term memory, and begin to provide a neural explanation for the typical advantage of deep over shallow study processing for later episodic memory. Copyright © 2011 Wiley Periodicals, Inc.

Sources of interference in item and associative recognition memory.

PubMed

Osth, Adam F; Dennis, Simon

2015-04-01

A powerful theoretical framework for exploring recognition memory is the global matching framework, in which a cue's memory strength reflects the similarity of the retrieval cues being matched against the contents of memory simultaneously. Contributions at retrieval can be categorized as matches and mismatches to the item and context cues, including the self match (match on item and context), item noise (match on context, mismatch on item), context noise (match on item, mismatch on context), and background noise (mismatch on item and context). We present a model that directly parameterizes the matches and mismatches to the item and context cues, which enables estimation of the magnitude of each interference contribution (item noise, context noise, and background noise). The model was fit within a hierarchical Bayesian framework to 10 recognition memory datasets that use manipulations of strength, list length, list strength, word frequency, study-test delay, and stimulus class in item and associative recognition. Estimates of the model parameters revealed at most a small contribution of item noise that varies by stimulus class, with virtually no item noise for single words and scenes. Despite the unpopularity of background noise in recognition memory models, background noise estimates dominated at retrieval across nearly all stimulus classes with the exception of high frequency words, which exhibited equivalent levels of context noise and background noise. These parameter estimates suggest that the majority of interference in recognition memory stems from experiences acquired before the learning episode. (c) 2015 APA, all rights reserved).

Working Memory and Strategy Use Contribute to Gender Differences in Spatial Ability

ERIC Educational Resources Information Center

Wang, Lu; Carr, Martha

2014-01-01

In this review, a new model that is grounded in information-processing theory is proposed to account for gender differences in spatial ability. The proposed model assumes that the relative strength of working memory, as expressed by the ratio of visuospatial working memory to verbal working memory, influences the type of strategies used on spatial…

Delusion of inanimate doubles: description of a case of focal retrograde amnesia.

PubMed

Abbate, Carlo; Trimarchi, Pietro Davide; Salvi, Gian Pietro; Quarenghi, Anna Maria; Vergani, Carlo; Luzzatti, Claudio

2012-01-01

This paper reports the case of a patient, M.P., who developed delusion of inanimate doubles, without Capgras syndrome, after traumatic brain injury. His delusional symptoms were studied longitudinally and the cognitive impairments associated with delusion were investigated. Data suggest that M.P. did 'perceive' the actual differences between doubles and originals rather than 'confabulate' them. The cognitive profile, characterized by retrograde episodic amnesia, but neither object processing impairment nor confabulations, supports this hypothesis. The study examines the nature of object misidentification based on Ellis' and Staton's account and proposes a new account based on concurrent unbiased retrieval of semantic memory traces and biased recollection of episodic memory traces.

Long-Term Memory and the Control of Attentional Control

PubMed Central

Mayr, Ulrich; Kuhns, David; Hubbard, Jason

2014-01-01

Task-switch costs and in particular the switch-cost asymmetry (i.e., the larger costs of switching to a dominant than a non-dominant task) are usually explained in terms of trial-to-trial carry-over of task-specific control settings. Here we argue that task switches are just one example of situations that trigger a transition from working-memory maintenance to updating, thereby opening working memory to interference from long-term memory. We used a new paradigm that requires selecting a spatial location either on the basis of a central cue (i.e., endogenous control of attention) or a peripheral, sudden onset (i.e., exogenous control of attention). We found a strong cost asymmetry that occurred even after short interruptions of otherwise single-task blocks (Exp. 1-3), but that was much stronger when participants had experienced the competing task under conditions of conflict (Exp. 1-2). Experiment 3 showed that the asymmetric costs were due to interruptions per se, rather than to associative interference tied to specific interruption activities. Experiment 4 generalized the basic pattern across interruptions varying in length or control demands and Experiment 5 across primary tasks with response-selection conflict rather than attentional conflict. Combined, the results support a model in which costs of selecting control settings arise when (a) potentially interfering memory traces have been encoded in long-term memory and (b) working-memory is forced from a maintenance mode into an updating mode (e.g., through task interruptions), thereby allowing unwanted retrieval of the encoded memory traces. PMID:24650696

Visual memory in unilateral spatial neglect: immediate recall versus delayed recognition.

PubMed

Moreh, Elior; Malkinson, Tal Seidel; Zohary, Ehud; Soroker, Nachum

2014-09-01

Patients with unilateral spatial neglect (USN) often show impaired performance in spatial working memory tasks, apart from the difficulty retrieving "left-sided" spatial data from long-term memory, shown in the "piazza effect" by Bisiach and colleagues. This study's aim was to compare the effect of the spatial position of a visual object on immediate and delayed memory performance in USN patients. Specifically, immediate verbal recall performance, tested using a simultaneous presentation of four visual objects in four quadrants, was compared with memory in a later-provided recognition task, in which objects were individually shown at the screen center. Unlike healthy controls, USN patients showed a left-side disadvantage and a vertical bias in the immediate free recall task (69% vs. 42% recall for right- and left-sided objects, respectively). In the recognition task, the patients correctly recognized half of "old" items, and their correct rejection rate was 95.5%. Importantly, when the analysis focused on previously recalled items (in the immediate task), no statistically significant difference was found in the delayed recognition of objects according to their original quadrant of presentation. Furthermore, USN patients were able to recollect the correct original location of the recognized objects in 60% of the cases, well beyond chance level. This suggests that the memory trace formed in these cases was not only semantic but also contained a visuospatial tag. Finally, successful recognition of objects missed in recall trials points to formation of memory traces for neglected contralesional objects, which may become accessible to retrieval processes in explicit memory.

Acute treatment with bis selenide, an organic compound containing the trace element selenium, prevents memory deficits induced by reserpine in rats.

PubMed

Bortolatto, Cristiani Folharini; Guerra Souza, Ana Cristina; Wilhelm, Ethel Antunes; Nogueira, Cristina Wayne

2013-01-01

Taking into account the promising pharmacological actions of (Z)-2,3-bis(4-chlorophenylselanyl) prop-2-en-1-ol) (bis selenide), an organic compound containing the trace element selenium, and the constant search for drugs that improve the cognitive performance, the objective of the present study was to investigate whether bis selenide treatment ameliorates memory deficits induced by reserpine in rats. For this aim, male adult rats received a single subcutaneous injection of reserpine (1 mg/kg), a biogenic amine-depleting agent used to induce memory deficit. After 24 h, bis selenide at doses of 25 and 50 mg/kg was administered to rats by intragastric route, and 1 h later, the animals were submitted to behavior tasks. The effects of acute administration of bis selenide on memory were evaluated by social recognition, step-down passive avoidance, and object recognition paradigms. Exploratory and locomotor activities of rats were determined using the open-field test. Analysis of data revealed that the social memory disruption caused by reserpine was reversed by bis selenide at both doses. In addition, bis selenide, at the highest dose, prevented the memory deficit resulting from reserpine administration to rats in step-down passive avoidance and object recognition tasks. No significant alterations in locomotor and exploratory behaviors were found in animals treated with reserpine and/or bis selenide. Results obtained from distinct memory behavioral paradigms revealed that an acute treatment with bis selenide attenuated memory deficits induced by reserpine in rats.

The Event Related Brain Potential as an Index of Information Processing, Cognitive Activity, and Skill Acquisition: A Program of Basic Research.

DTIC Science & Technology

1983-10-01

representations in memory as multidimensional "traces" containing infqrmation on both semantic and nonsemantic attributes. Isolation in this study results...effect and induced amnesia : Production by manipulation of sound intensity. Journal of Experimental Psychology: Human Learning and Memory , 1, 614-628...Thomson, D.M. (1973). Encoding specificity and retrieval processes in episodic memory . Psychological Review, 80, 352-373. .. -- "V- - ’. 4 -- .7 ’. ... . n

Mnemons: encoding memory by protein super-assembly.

PubMed

Caudron, Fabrice; Barral, Yves

2014-02-25

Memory is mainly understood as the recollection of past events. The human brain and its simplest unit, the synapse, belong to the places in which such memories are physically stored. From an experimental point of view, memory can be tested in humans by recall. However, in other organisms, memory is reflected in its use by individuals to learn about and adapt their behavior to their environment. Under this criterion, even unicellular organisms are able to learn from their environments and show the ability to adapt their responses to repeating stimuli. This indicates that they are able to keep track of their histories and use these traces to elaborate adapted responses, making these traces akin to memory encodings. Understanding these phenomena may even help us to dissect part of the rather complex molecular orchestration happening in our synapses. When exposed unsuccessfully to mating pheromone, i.e. when mating does not happen, budding yeast cells become refractory to the mating signal. This refractory state is restricted to the mother cell and not inherited by the daughter cells, even though it is stable for most if not the entire life span of the mother cell. Interestingly, both stability and asymmetric segregation of the acquired state are explained by the molecular mechanism underlying its establishment, which shows important analogies and distinctions to prions. Here we discuss these similarities and differences.

Asynchronous ripple oscillations between left and right hippocampi during slow-wave sleep

PubMed Central

Villalobos, Claudio

2017-01-01

Spatial memory, among many other brain processes, shows hemispheric lateralization. Most of the published evidence suggests that the right hippocampus plays a leading role in the manipulation of spatial information. Concurrently in the hippocampus, memory consolidation during sleep periods is one of the key steps in the formation of newly acquired spatial memory traces. One of the most characteristic oscillatory patterns in the hippocampus are sharp-wave ripple (SWR) complexes. Within this complex, fast-field oscillations or ripples have been demonstrated to be instrumental in the memory consolidation process. Since these ripples are relevant for the consolidation of memory traces associated with spatial navigation, and this process appears to be lateralized, we hypothesize that ripple events between both hippocampi would exhibit different temporal dynamics. We tested this idea by using a modified "split-hyperdrive" that allows us to record simultaneous LFPs from both right and left hippocampi of Sprague-Dawley rats during sleep. We detected individual events and found that during sleep periods these ripples exhibited a different occurrence patterns between hemispheres. Most ripple events were synchronous between intra- rather than inter-hemispherical recordings, suggesting that ripples in the hippocampus are independently generated and locally propagated within a specific hemisphere. In this study, we propose the ripples’ lack of synchrony between left and right hippocampi as the putative physiological mechanism underlying lateralization of spatial memory. PMID:28158285

Asynchronous ripple oscillations between left and right hippocampi during slow-wave sleep.

PubMed

Villalobos, Claudio; Maldonado, Pedro E; Valdés, José L

2017-01-01

Spatial memory, among many other brain processes, shows hemispheric lateralization. Most of the published evidence suggests that the right hippocampus plays a leading role in the manipulation of spatial information. Concurrently in the hippocampus, memory consolidation during sleep periods is one of the key steps in the formation of newly acquired spatial memory traces. One of the most characteristic oscillatory patterns in the hippocampus are sharp-wave ripple (SWR) complexes. Within this complex, fast-field oscillations or ripples have been demonstrated to be instrumental in the memory consolidation process. Since these ripples are relevant for the consolidation of memory traces associated with spatial navigation, and this process appears to be lateralized, we hypothesize that ripple events between both hippocampi would exhibit different temporal dynamics. We tested this idea by using a modified "split-hyperdrive" that allows us to record simultaneous LFPs from both right and left hippocampi of Sprague-Dawley rats during sleep. We detected individual events and found that during sleep periods these ripples exhibited a different occurrence patterns between hemispheres. Most ripple events were synchronous between intra- rather than inter-hemispherical recordings, suggesting that ripples in the hippocampus are independently generated and locally propagated within a specific hemisphere. In this study, we propose the ripples' lack of synchrony between left and right hippocampi as the putative physiological mechanism underlying lateralization of spatial memory.

Duration of the unconditioned stimulus in appetitive conditioning of honeybees differentially impacts learning, long-term memory strength, and the underlying protein synthesis

PubMed Central

Marter, Kathrin; Grauel, M. Katharina; Lewa, Carmen; Morgenstern, Laura; Buckemüller, Christina; Heufelder, Karin; Ganz, Marion

2014-01-01

This study examines the role of stimulus duration in learning and memory formation of honeybees (Apis mellifera). In classical appetitive conditioning honeybees learn the association between an initially neutral, conditioned stimulus (CS) and the occurrence of a meaningful stimulus, the unconditioned stimulus (US). Thereby the CS becomes a predictor for the US eliciting a conditioned response (CR). Here we study the role of US duration in classical conditioning by examining honeybees conditioned with different US durations. We quantify the CR during acquisition, memory retention, and extinction of the early long-term memory (eLTM), and examine the molecular mechanisms of eLTM by interfering with protein synthesis. We find that the US duration affects neither the probability nor the strength of the CR during acquisition, eLTM retention, and extinction 24 h after conditioning. However, we find that the resistance to extinction 24 h after conditioning is susceptible to protein synthesis inhibition depending on the US duration. We conclude that the US duration does not affect the predictability of the US but modulates the protein synthesis underlying the eLTM's strength. Thus, the US duration differentially impacts learning, eLTM strength, and its underlying protein synthesis. PMID:25403456

Interactions of trace metals with hydrogels and filter membranes used in DET and DGT techniques.

PubMed

Garmo, Oyvind A; Davison, William; Zhang, Hao

2008-08-01

Equilibrium partitioning of trace metals between bulk solution and hydrogels/filter was studied. Under some conditions, trace metal concentrations were higher in the hydrogels or filter membranes compared to bulk solution (enrichment). In synthetic soft water, enrichment of cationic trace metals in polyacrylamide hydrogels decreased with increasing trace metal concentration. Enrichment was little affected by Ca and Mg in the concentration range typically encountered in natural freshwaters, indicating high affinity but low capacity binding of trace metals to solid structure in polyacrylamide gels. The apparent binding strength decreased in the sequence: Cu > Pb > Ni approximately to Cd approximately to Co and a low concentration of cationic Cu eliminated enrichment of weakly binding trace metal cations. The polyacrylamide gels also had an affinity for fulvic acid and/or its trace metal complexes. Enrichment of cationic Cd in agarose gel and hydrophilic polyethersulfone filter was independent of concentration (10 nM to 5 microM) but decreased with increasing Ca/ Mg concentration and ionic strength, suggesting that it is mainly due to electrostatic interactions. However, Cu and Pb were enriched even after equilibration in seawater, indicating that these metals additionally bind to sites within the agarose gel and filter. Compared to the polyacrylamide gels, agarose gel had a lower affinity for metal-fulvic complexes. Potential biases in measurements made with the diffusive equilibration in thin-films (DET) technique, identified by this work, are discussed.

In Search for Boundary Conditions of Reconsolidation: A Failure of Fear Memory Interference

PubMed Central

Schroyens, Natalie; Beckers, Tom; Kindt, Merel

2017-01-01

The presentation of a fear memory cue can result in mere memory retrieval, destabilization of the reactivated memory trace, or the formation of an extinction memory. The interaction between the degree of novelty during reactivation and previous learning conditions is thought to determine the outcome of a reactivation session. This study aimed to evaluate whether contextual novelty can prevent cue-induced destabilization and disruption of a fear memory acquired by non-asymptotic learning. To this end, fear memory was reactivated in a novel context or in the original context of learning, and fear memory reactivation was followed by the administration of propranolol, an amnestic drug. Remarkably, fear memory was not impaired by post-reactivation propranolol administration or extinction training under the usual conditions used in our lab, irrespective of the reactivation context. These unexpected findings are discussed in the light of our current experimental parameters and alleged boundary conditions on memory destabilization. PMID:28469565

Adolescent and Adult Rats Differ in the Amnesic Effects of Acute Ethanol in Two Hippocampus-Dependent Tasks: Trace and Contextual Fear Conditioning

PubMed Central

Hunt, Pamela S.; Barnet, Robert C.

2015-01-01

Experience-produced deficits in trace conditioning and context conditioning have been useful tools for examining the role of the hippocampus in learning. It has also been suggested that learning in these tasks is especially vulnerable to neurotoxic effects of alcohol during key developmental periods such as adolescence. In five experiments we systematically examined the presence and source of age-dependent vulnerability to the memory-disrupting effects of acute ethanol in trace conditioning and contextual fear conditioning. In Experiment 1a pre-training ethanol disrupted trace conditioning more strongly in adolescent (postnatal day, PD30-35) than adult rats (PD65-75). In Experiment 1b when pre-training ethanol was accompanied by pre-test ethanol no deficit in trace conditioning was observed in adolescents, suggesting that state-dependent retrieval failure mediated ethanol's disruption of trace conditioning at this age. Experiments 2a and 2b examined the effect of ethanol pretreatment on context conditioning. Here, adult but not adolescent rats were impaired in conditioned freezing to context cues. Experiment 2c explored state-dependency of this effect. Pre-training ethanol continued to disrupt context conditioning in adults even when ethanol was also administered prior to test. Collectively these findings reveal clear age-dependent and task-dependent vulnerabilities in ethanol's disruptive effects on hippocampus-dependent memory. Adolescents were more disrupted by ethanol in trace conditioning than adults, and adults were more disrupted by ethanol in context conditioning than adolescents. We suggest that adolescents may be more susceptible to changes in internal state (state-dependent retrieval failure) than adults and that ethanol disrupted performance in trace and context conditioning through different mechanisms. Relevance of these findings to theories of hippocampus function is discussed. PMID:26192910

Short-term memory for pictures seen once or twice.

PubMed

Martini, Paolo; Maljkovic, Vera

2009-06-01

The present study is concerned with the effects of exposure time, repetition, spacing and lag on old/new recognition memory for generic visual scenes presented in a RSVP paradigm. Early memory studies with verbal material found that knowledge of total exposure time at study is sufficient to accurately predict memory performance at test (the Total Time Hypothesis), irrespective of number of repetitions, spacing or lag. However, other studies have disputed such simple dependence of memory strength on total study time, demonstrating super-additive facilitatory effects of spacing and lag, as well as inhibitory effects, such as the Ranschburg effect, Repetition Blindness and the Attentional Blink. In the experimental conditions of the present study we find no evidence of either facilitatory or inhibitory effects: recognition memory for pictures in RSVP supports the Total Time Hypothesis. The data are consistent with an Unequal-Variance Signal Detection Theory model of memory that assumes the average strength and the variance of the familiarity of pictures both increase with total study time. The main conclusion is that the growth of visual scene familiarity with temporal exposure and repetition is a stochastically independent process.

Regulation of Local Ambient GABA Levels via Transporter-Mediated GABA Import and Export for Subliminal Learning.

PubMed

Hoshino, Osamu

2015-06-01

Perception of supraliminal stimuli might in general be reflected in bursts of action potentials (spikes), and their memory traces could be formed through spike-timing-dependent plasticity (STDP). Memory traces for subliminal stimuli might be formed in a different manner, because subliminal stimulation evokes a fraction (but not a burst) of spikes. Simulations of a cortical neural network model showed that a subliminal stimulus that was too brief (10 msec) to perceive transiently (more than about 500 msec) depolarized stimulus-relevant principal cells and hyperpolarized stimulus-irrelevant principal cells in a subthreshold manner. This led to a small increase or decrease in ongoing-spontaneous spiking activity frequency (less than 1 Hz). Synaptic modification based on STDP during this period effectively enhanced relevant synaptic weights, by which subliminal learning was improved. GABA transporters on GABAergic interneurons modulated local levels of ambient GABA. Ambient GABA molecules acted on extrasynaptic receptors, provided principal cells with tonic inhibitory currents, and contributed to achieving the subthreshold neuronal state. We suggest that ongoing-spontaneous synaptic alteration through STDP following subliminal stimulation may be a possible neuronal mechanism for leaving its memory trace in cortical circuitry. Regulation of local ambient GABA levels by transporter-mediated GABA import and export may be crucial for subliminal learning.

Evidence for recovery of fear following immediate extinction in rats and humans

PubMed Central

Schiller, Daniela; Cain, Christopher K.; Curley, Nina G.; Schwartz, Jennifer S.; Stern, Sarah A.; LeDoux, Joseph E.; Phelps, Elizabeth A.

2008-01-01

Fear responses can be eliminated through extinction, a procedure involving the presentation of fear-eliciting stimuli without aversive outcomes. Extinction is believed to be mediated by new inhibitory learning that acts to suppress fear expression without erasing the original memory trace. This hypothesis is supported mainly by behavioral data demonstrating that fear can recover following extinction. However, a recent report by Myers and coworkers suggests that extinction conducted immediately after fear learning may erase or prevent the consolidation of the fear memory trace. Since extinction is a major component of nearly all behavioral therapies for human fear disorders, this finding supports the notion that therapeutic intervention beginning very soon after a traumatic event will be more efficacious. Given the importance of this issue, and the controversy regarding immediate versus delayed therapeutic interventions, we examined two fear recovery phenomena in both rats and humans: spontaneous recovery (SR) and reinstatement. We found evidence for SR and reinstatement in both rats and humans even when extinction was conducted immediately after fear learning. Thus, our data do not support the hypothesis that immediate extinction erases the original memory trace, nor do they suggest that a close temporal proximity of therapeutic intervention to the traumatic event might be advantageous. PMID:18509113

Contextual Distinctiveness Produces Long-Lasting Priming of Pop-Out

ERIC Educational Resources Information Center

Thomson, David R.; Milliken, Bruce

2013-01-01

Maljkovic and Nakayama have demonstrated memory influences in singleton search from one trial to the next, an effect they termed "priming of pop-out" (PoP). This effect was described as resulting from the persistence of an implicit memory trace, the influence of which could be observed for around 5-8 subsequent trials. Thomson and…

Momentary Forgetting: Entering and Leaving the TOT State.

ERIC Educational Resources Information Center

Ryan, Michael P.

People sometimes forget a name or a word, and are plagued by the feeling that the sought-for word is somewhere in memory but not immediately available. The frequent description of this tip-of-the-tongue (TOT) phenomenon as subthreshold memory traces is challenged by data showing that TOT genesis and TOT recovery are distinct processes. In a verbal…

Behind the Scenes of Music Education in China: A Survey of Historical Memory

ERIC Educational Resources Information Center

Ho, Wai-Chung

2013-01-01

This study explores how the government of mainland China values Chinese nationalism as a component of its historical memory and traces its relationship with music education from the twentieth century to the global age within broader social contexts. In a rapidly commercializing and modernizing China, nationalism remains the main driving force…

Designs of Concept Maps and Their Impacts on Readers' Performance in Memory and Reasoning while Reading

ERIC Educational Resources Information Center

Tzeng, Jeng-Yi

2010-01-01

From the perspective of the Fuzzy Trace Theory, this study investigated the impacts of concept maps with two strategic orientations (comprehensive and thematic representations) on readers' performance of cognitive operations (such as perception, verbatim memory, gist reasoning and syntheses) while the readers were reading two history articles that…

Corrective Feedback and Working Memory Capacity in Interaction-Driven L2 Learning

ERIC Educational Resources Information Center

Goo, Jaemyung

2012-01-01

The present study explores the relative efficacy of recasts over metalinguistic feedback on the learning of the English "that"-trace filter and how working memory capacity (WMC) is related to the extent to which learners can benefit from recasts and metalinguistic feedback. Fifty-four Korean English as a foreign language (EFL) learners…

On the Status of Cue Independence as a Criterion for Memory Inhibition: Evidence against the Covert Blocking Hypothesis

ERIC Educational Resources Information Center

Weller, Peter D.; Anderson, Michael C.; Gómez-Ariza, Carlos J.; Bajo, M. Teresa

2013-01-01

Retrieving memories can impair recall of other related traces. Items affected by this retrieval-induced forgetting (RIF) are often less accessible when tested with independent probes, a characteristic known as cue independence. Cue independence has been interpreted as evidence for inhibitory mechanisms that suppress competing items during…

Individuals' Self-Defining Memories as Reflecting Their Strength and Weaknesses

ERIC Educational Resources Information Center

Goldner, Limor; Scharf, Miri

2017-01-01

The associations between attachment orientations, temperament, resilience, and various dimensions of self-defining memories were examined in 83 female Israeli adolescents and young adults. Resiliency and positive temperament were associated with positive qualities of memories, whereas negative emotionality and reactivity were associated with poor…

Dipeptide preparation Noopept prevents scopolamine-induced deficit of spatial memory in BALB/c mice.

PubMed

Belnik, A P; Ostrovskaya, R U; Poletaeva, I I

2007-04-01

The effect of original nootropic preparation Noopept on learning and long-term memory was studied with BALB/c mice. Scopolamine (1 mg/kg) impaired long-term memory trace, while Noopept (0.5 mg/kg) had no significant effect. Noopept completely prevented the development of cognitive disorders induced by scopolamine (blockade of muscarinic cholinergic receptors). Our results confirmed the presence of choline-positive effect in dipeptide piracetam analogue Noopept on retrieval of learned skill of finding a submerged platform (spatial memory). We conclude that the effectiveness of this drug should be evaluated in patients with Alzheimer's disease.

Robust relationship between reading span and speech recognition in noise

PubMed Central

Souza, Pamela; Arehart, Kathryn

2015-01-01

Objective Working memory refers to a cognitive system that manages information processing and temporary storage. Recent work has demonstrated that individual differences in working memory capacity measured using a reading span task are related to ability to recognize speech in noise. In this project, we investigated whether the specific implementation of the reading span task influenced the strength of the relationship between working memory capacity and speech recognition. Design The relationship between speech recognition and working memory capacity was examined for two different working memory tests that varied in approach, using a within-subject design. Data consisted of audiometric results along with the two different working memory tests; one speech-in-noise test; and a reading comprehension test. Study sample The test group included 94 older adults with varying hearing loss and 30 younger adults with normal hearing. Results Listeners with poorer working memory capacity had more difficulty understanding speech in noise after accounting for age and degree of hearing loss. That relationship did not differ significantly between the two different implementations of reading span. Conclusions Our findings suggest that different implementations of a verbal reading span task do not affect the strength of the relationship between working memory capacity and speech recognition. PMID:25975360

Robust relationship between reading span and speech recognition in noise.

PubMed

Souza, Pamela; Arehart, Kathryn

2015-01-01

Working memory refers to a cognitive system that manages information processing and temporary storage. Recent work has demonstrated that individual differences in working memory capacity measured using a reading span task are related to ability to recognize speech in noise. In this project, we investigated whether the specific implementation of the reading span task influenced the strength of the relationship between working memory capacity and speech recognition. The relationship between speech recognition and working memory capacity was examined for two different working memory tests that varied in approach, using a within-subject design. Data consisted of audiometric results along with the two different working memory tests; one speech-in-noise test; and a reading comprehension test. The test group included 94 older adults with varying hearing loss and 30 younger adults with normal hearing. Listeners with poorer working memory capacity had more difficulty understanding speech in noise after accounting for age and degree of hearing loss. That relationship did not differ significantly between the two different implementations of reading span. Our findings suggest that different implementations of a verbal reading span task do not affect the strength of the relationship between working memory capacity and speech recognition.

Memory processing in great apes: the effect of time and sleep

PubMed Central

Martin-Ordas, Gema; Call, Josep

2011-01-01

Following encoding, memory remains temporarily vulnerable to disruption. Consolidation refers to offline time-dependent processes that continue after encoding and stabilize, transform or enhance the memory trace. Memory consolidation resulting from sleep has been reported for declarative and non-declarative memories in humans. We first investigated the temporal course of memory retrieval in chimpanzees, bonobos and orangutans. We found that the amount of retrieved information was time dependent: apes' performance degraded after 1 and 2 h, stabilized after 4 h, started to increase after 8 and 12 h and fully recovered after 24 h. Second, we show that although memories during wakefulness were highly vulnerable to interference from events similar to those witnessed during the original encoding event, an intervening period of sleep not only stabilized apes' memories into more permanent ones but also protected them against interference. PMID:21632621

Memory processing in great apes: the effect of time and sleep.

PubMed

Martin-Ordas, Gema; Call, Josep

2011-12-23

Following encoding, memory remains temporarily vulnerable to disruption. Consolidation refers to offline time-dependent processes that continue after encoding and stabilize, transform or enhance the memory trace. Memory consolidation resulting from sleep has been reported for declarative and non-declarative memories in humans. We first investigated the temporal course of memory retrieval in chimpanzees, bonobos and orangutans. We found that the amount of retrieved information was time dependent: apes' performance degraded after 1 and 2 h, stabilized after 4 h, started to increase after 8 and 12 h and fully recovered after 24 h. Second, we show that although memories during wakefulness were highly vulnerable to interference from events similar to those witnessed during the original encoding event, an intervening period of sleep not only stabilized apes' memories into more permanent ones but also protected them against interference.

Schemas and memory consolidation.

PubMed

Tse, Dorothy; Langston, Rosamund F; Kakeyama, Masaki; Bethus, Ingrid; Spooner, Patrick A; Wood, Emma R; Witter, Menno P; Morris, Richard G M

2007-04-06

Memory encoding occurs rapidly, but the consolidation of memory in the neocortex has long been held to be a more gradual process. We now report, however, that systems consolidation can occur extremely quickly if an associative "schema" into which new information is incorporated has previously been created. In experiments using a hippocampal-dependent paired-associate task for rats, the memory of flavor-place associations became persistent over time as a putative neocortical schema gradually developed. New traces, trained for only one trial, then became assimilated and rapidly hippocampal-independent. Schemas also played a causal role in the creation of lasting associative memory representations during one-trial learning. The concept of neocortical schemas may unite psychological accounts of knowledge structures with neurobiological theories of systems memory consolidation.

Dilution as a Model of Long-Term Forgetting

ERIC Educational Resources Information Center

Lansdale, Mark; Baguley, Thom

2008-01-01

This article presents a model of long term forgetting based on 3 ideas: (a) Memory for a stimulus can be described by a population of accessible traces; (b) probability of retrieval after a delay is predicted by the proportion of traces in this population that will be defined as correct if sampled; and (c) this population is diluted over time by…

Using warnings to reduce categorical false memories in younger and older adults.

PubMed

Carmichael, Anna M; Gutchess, Angela H

2016-07-01

Warnings about memory errors can reduce their incidence, although past work has largely focused on associative memory errors. The current study sought to explore whether warnings could be tailored to specifically reduce false recall of categorical information in both younger and older populations. Before encoding word pairs designed to induce categorical false memories, half of the younger and older participants were warned to avoid committing these types of memory errors. Older adults who received a warning committed fewer categorical memory errors, as well as other types of semantic memory errors, than those who did not receive a warning. In contrast, young adults' memory errors did not differ for the warning versus no-warning groups. Our findings provide evidence for the effectiveness of warnings at reducing categorical memory errors in older adults, perhaps by supporting source monitoring, reduction in reliance on gist traces, or through effective metacognitive strategies.

Skills, Plans, and Self-Regulation. Technical Report No. 48.

ERIC Educational Resources Information Center

Brown, Ann L.; DeLoache, Judy S.

The first section of this report reviews traditional memory studies, which have provided much of our information concerning memory development. Major strengths and weaknesses of memory-development studies are illustrated by comparison with recent research into children's problem-solving skills. The report concentrates on one area of general…

Memory and Neuropsychology in Down Syndrome

ERIC Educational Resources Information Center

Jarrold, Christopher; Nadel, Lynn; Vicari, Stefano

2009-01-01

This paper outlines the strengths and weaknesses in both short-term and long-term memory in Down syndrome, and the implications of these patterns for both other aspects of cognitive development and underlying neural pathology. There is clear evidence that Down syndrome is associated with particularly poor verbal short-term memory performance, and…

Trace Fear Conditioning Differentially Modulates Intrinsic Excitability of Medial Prefrontal Cortex-Basolateral Complex of Amygdala Projection Neurons in Infralimbic and Prelimbic Cortices.

PubMed

Song, Chenghui; Ehlers, Vanessa L; Moyer, James R

2015-09-30

Neuronal activity in medial prefrontal cortex (mPFC) is critical for the formation of trace fear memory, yet the cellular mechanisms underlying these memories remain unclear. One possibility involves the modulation of intrinsic excitability within mPFC neurons that project to the basolateral complex of amygdala (BLA). The current study used a combination of retrograde labeling and in vitro whole-cell patch-clamp recordings to examine the effect of trace fear conditioning on the intrinsic excitability of layer 5 mPFC-BLA projection neurons in adult rats. Trace fear conditioning significantly enhanced the intrinsic excitability of regular spiking infralimbic (IL) projection neurons, as evidenced by an increase in the number of action potentials after current injection. These changes were also associated with a reduction in spike threshold and an increase in h current. In contrast, trace fear conditioning reduced the excitability of regular spiking prelimbic (PL) projection neurons, through a learning-related decrease of input resistance. Interestingly, the amount of conditioned freezing was (1) positively correlated with excitability of IL-BLA projection neurons after conditioning and (2) negatively correlated with excitability of PL-BLA projection neurons after extinction. Trace fear conditioning also significantly enhanced the excitability of burst spiking PL-BLA projection neurons. In both regions, conditioning-induced plasticity was learning specific (observed in conditioned but not in pseudoconditioned rats), flexible (reversed by extinction), and transient (lasted <10 d). Together, these data suggest that intrinsic plasticity within mPFC-BLA projection neurons occurs in a subregion- and cell-type-specific manner during acquisition, consolidation, and extinction of trace fear conditioning. Significance statement: Frontal lobe-related function is vital for a variety of important behaviors, some of which decline during aging. This study involves a novel combination of electrophysiological recordings from fluorescently labeled mPFC-to-amygdala projection neurons in rats with acquisition and extinction of trace fear conditioning to determine how specific neurons change during behavior. This is the first study to demonstrate that trace fear conditioning significantly alters the intrinsic excitability of mPFC-to-amygdala projection neurons in a subregion- and cell-type-specific manner, which is also transient and reversed by extinction. These data are of broad interest to the neuroscientific community, and the results will inspire additional studies investigating the cellular mechanisms underlying circuit-specific changes within the brain as a result of associative learning and memory. Copyright © 2015 the authors 0270-6474/15/3513511-14$15.00/0.

Time-dependent reorganization of the brain components underlying memory retention in trace eyeblink conditioning.

PubMed

Takehara, Kaori; Kawahara, Shigenori; Kirino, Yutaka

2003-10-29

Many studies have confirmed the time-limited involvement of the hippocampus in mnemonic processes and suggested that there is reorganization of the responsible brain circuitry during memory consolidation. To clarify such reorganization, we chose trace classical eyeblink conditioning, in which hippocampal ablation produces temporally graded retrograde amnesia. Here, we extended the temporal characterization of retrograde amnesia to other regions that are involved in acquisition during this task: the medial prefrontal cortex (mPFC) and the cerebellum. At a various time interval after establishing the trace conditioned response (CR), rats received an aspiration of one of the three regions. After recovery, the animals were tested for their CR retention. When ablated 1 d after the learning, both the hippocampal lesion and the cerebellar lesion group of rats exhibited a severe impairment in retention of the CR, whereas the mPFC lesion group showed only a slight decline. With an increase in interval between the lesion and the learning, the effect of the hippocampal lesion diminished and that of the mPFC lesion increased. When ablated 4 weeks after the learning, the hippocampal lesion group exhibited as robust CRs as its corresponding control group. In contrast, the mPFC lesion and the cerebellar lesion groups failed to retain the CRs. These results indicate that the hippocampus and the cerebellum, but only marginally the mPFC, constitute a brain circuitry that mediates recently acquired memory. As time elapses, the circuitry is reorganized to use mainly the mPFC and the cerebellum, but not the hippocampus, for remotely acquired memory.

Biological and epistemological models of localization in the nineteenth century: from Gall to Charcot.

PubMed

Kaitaro, T

2001-12-01

In the latter half of the nineteenth century, the localizationist doctrines became closely associated with the memory trace paradigm. The analysis of the texts dealing with the localization and the nature of 'the loss of articulated speech' (motor aphasia) by Bouillaud, Lordat, Dax, Broca, Trousseau, Baillarger, Charcot and Wernicke shows how the biological paradigm of localization presented by Gall and based on the notion of organ-function correspondence was transformed into a model based on localizable memory traces. This change resulted in the theoretical unification of the mechanisms of motor and non-motor forms of aphasia. These forms, which the earlier authors tended to separate in their analyses of the underlying mechanisms, were now regarded as involving similar mechanisms related to the loss of mnestic images. The crucial step in this development was taken by Broca who presented the hypothesis that the faculty of coordination of speech movements, which according to his predecessors was the faculty lost in motor aphasia, was actually an intellectual faculty and a specific form of memory, and motor aphasia consequently a selective kind of amnesia. Theorists like Charcot and Wernicke generalized this idea into a comprehensive theory of the nature of localization based on the notion of memory traces. Thus, the localization of function was reduced to the localization of representations. Instead of biological paradigms, this model of localization is rooted in the epistemological tradition of psychology represented by Locke and Condillac, who were primarily interested in the problem of representation. In physiology, this approach usually resulted in attempts at localizing representations instead of functions.

A simplified conjoint recognition paradigm for the measurement of gist and verbatim memory.

PubMed

Stahl, Christoph; Klauer, Karl Christoph

2008-05-01

The distinction between verbatim and gist memory traces has furthered the understanding of numerous phenomena in various fields, such as false memory research, research on reasoning and decision making, and cognitive development. To measure verbatim and gist memory empirically, an experimental paradigm and multinomial measurement model has been proposed but rarely applied. In the present article, a simplified conjoint recognition paradigm and multinomial model is introduced and validated as a measurement tool for the separate assessment of verbatim and gist memory processes. A Bayesian metacognitive framework is applied to validate guessing processes. Extensions of the model toward incorporating the processes of phantom recollection and erroneous recollection rejection are discussed.

Memory Before and After Sleep in Patients with Moderate Obstructive Sleep Apnea

PubMed Central

Kloepfer, Corinna; Riemann, Dieter; Nofzinger, Eric A.; Feige, Bernd; Unterrainer, Josef; O'Hara, Ruth; Sorichter, Stephan; Nissen, Christoph

2009-01-01

Objective: The aim of this study was to investigate the effects of obstructive sleep apnea (OSA) on procedural and declarative memory encoding in the evening prior to sleep, on memory consolidation during subsequent sleep, and on retrieval in the morning after sleep. Methods: Memory performance (procedural mirror-tracing task, declarative visual and verbal memory task) and general neuropsychological performance were assessed before and after one night of polysomnographic monitoring in 15 patients with moderate OSA and 20 age-, sex-, and IQ-matched healthy subjects. Results: Encoding levels prior to sleep were similar across groups for all tasks. Conventional analyses of averaged mirror tracing performance suggested a significantly reduced overnight improvement in OSA patients. Single trial analyses, however, revealed that this effect was due to significantly flattened learning curves in the evening and morning session in OSA patients. OSA patients showed a significantly lower verbal retention rate and a non-significantly reduced visual retention rate after sleep compared to healthy subjects. Polysomnography revealed a significantly reduced REM density, increased frequency of micro-arousals, elevated apnea-hypopnea index, and subjectively disturbed sleep quality in OSA patients compared to healthy subjects. Conclusions: The results suggest that moderate OSA is associated with a significant impairment of procedural and verbal declarative memory. Future work is needed to further determine the contribution of structural or functional alterations in brain circuits relevant for memory, and to test whether OSA treatment improves or normalizes the observed deficits in learning. Citation: Kloepfer C; Riemann D; Nofzinger EA; Feige B; Unterrainer J; O'Hara R; Sorichter S; Nissen C. Memory before and after sleep in patients with moderate obstructive sleep apnea. J Clin Sleep Med 2009;5(6):540-548. PMID:20465021

Neural Correlates of Confidence during Item Recognition and Source Memory Retrieval: Evidence for Both Dual-Process and Strength Memory Theories

ERIC Educational Resources Information Center

Hayes, Scott M.; Buchler, Norbou; Stokes, Jared; Kragel, James; Cabeza, Roberto

2011-01-01

Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength…

Working memory for braille is shaped by experience.

PubMed

Cohen, Henri; Scherzer, Peter; Viau, Robert; Voss, Patrice; Lepore, Franco

2011-03-01

Tactile working memory was found to be more developed in completely blind (congenital and acquired) than in semi-sighted subjects, indicating that experience plays a crucial role in shaping working memory. A model of working memory, adapted from the classical model proposed by Baddeley and Hitch1 and Baddeley2 is presented where the connection strengths of a highly cross-modal network are altered through experience.

On Common Ground: Jost's (1897) Law of Forgetting and Ribot's (1881) Law of Retrograde Amnesia

ERIC Educational Resources Information Center

Wixted, John T.

2004-01-01

T. Ribot's (1881) law of retrograde amnesia states that brain damage impairs recently formed memories to a greater extent than older memories, which is generally taken to imply that memories need time to consolidate. A. Jost's (1897) law of forgetting states that if 2 memories are of the same strength but different ages, the older will decay more…

Places, Spaces and Memory Traces: Showing Students with Learning Disabilities Ways to Remember Locations and Events on Maps.

ERIC Educational Resources Information Center

Brigham, Frederick J.

This study examined the memory-enhancing effects of elaborative and mnemonic encoding of information presented with maps, compared to more traditional, non-mnemonic maps, on recall of locations of events and information associated with those events by 72 middle school students with learning disabilities. Subjects were presented with map-like…

Neural Evidence for a Distinction between Short-Term Memory and the Focus of Attention

ERIC Educational Resources Information Center

Lewis-Peacock, Jarrod A.; Drysdale, Andrew T.; Oberauer, Klaus; Postle, Bradley R.

2012-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay period activity may, in fact, reflect the focus of attention, rather than STM. We…

Prediction error and trace dominance determine the fate of fear memories after post-training manipulations

PubMed Central

Alfei, Joaquín M.; Ferrer Monti, Roque I.; Molina, Victor A.; Bueno, Adrián M.

2015-01-01

Different mnemonic outcomes have been observed when associative memories are reactivated by CS exposure and followed by amnestics. These outcomes include mere retrieval, destabilization–reconsolidation, a transitional period (which is insensitive to amnestics), and extinction learning. However, little is known about the interaction between initial learning conditions and these outcomes during a reinforced or nonreinforced reactivation. Here we systematically combined temporally specific memories with different reactivation parameters to observe whether these four outcomes are determined by the conditions established during training. First, we validated two training regimens with different temporal expectations about US arrival. Then, using Midazolam (MDZ) as an amnestic agent, fear memories in both learning conditions were submitted to retraining either under identical or different parameters to the original training. Destabilization (i.e., susceptibly to MDZ) occurred when reactivation was reinforced, provided the occurrence of a temporal prediction error about US arrival. In subsequent experiments, both treatments were systematically reactivated by nonreinforced context exposure of different lengths, which allowed to explore the interaction between training and reactivation lengths. These results suggest that temporal prediction error and trace dominance determine the extent to which reactivation produces the different outcomes. PMID:26179232

Revisiting the rise and fall of false recall: presentation rate effects depend on retention interval.

PubMed

Smith, Troy A; Kimball, Daniel R

2012-01-01

Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease--a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)--contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.

Report of the U.S. Geological Survey's evaluation program for standard reference samples distributed in April 1993; T-123 (trace constituents), T-125 (trace constituents), M-126 (major constituents, N-38 (nutrients), N-39 (nutrients), P-20 (low ionic strength, and Hg-16 (mercury)

USGS Publications Warehouse

Long, H.K.; Farrar, J.W.

1993-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for seven standard reference samples--T-123 (trace constituents), T-125 (trace constituents), M-126 (major constituents), N-38 (nutrients), N-39 (Nutrients), P-20 (precipitation-low ionic strength), and Hg-16 (mercury)--that were distributed in April 1993 to 175 laboratories registered in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data received from 131 of the laboratories were evaluated with respect to: overall laboratory performance and relative laboratory performance for each analyte in the 7 reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the seven standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

The Alba ray tracing code: ART

NASA Astrophysics Data System (ADS)

Nicolas, Josep; Barla, Alessandro; Juanhuix, Jordi

2013-09-01

The Alba ray tracing code (ART) is a suite of Matlab functions and tools for the ray tracing simulation of x-ray beamlines. The code is structured in different layers, which allow its usage as part of optimization routines as well as an easy control from a graphical user interface. Additional tools for slope error handling and for grating efficiency calculations are also included. Generic characteristics of ART include the accumulation of rays to improve statistics without memory limitations, and still providing normalized values of flux and resolution in physically meaningful units.

Memory and linguistic/executive functions of children with borderline intellectual functioning.

PubMed

Água Dias, Andrea B; Albuquerque, Cristina P; Simões, Mário R

2017-11-08

Children with Borderline Intellectual Functioning (BIF) have received a minimal amount of research attention and have been studied in conjunction with Intellectual and Developmental Disabilities. The present study intends to broaden the knowledge of BIF, by analyzing domains such as verbal memory and visual memory, as well as tasks that rely simultaneously on memory, executive functions, and language. A cross-sectional, comparison study was carried out between a group of 40 children with BIF (mean age = 10.03; 24 male and 16 female), and a control group of 40 normal children of the same age, gender, and socioeconomic level as the BIF group. The WISC-III Full Scale IQs of the BIF group ranged from 71 to 84. The following instruments were used: Word List, Narrative Memory, Rey Complex Figure, Face Memory, Rapid Naming (both RAN and RAS tests), and Verbal Fluency. The results showed deficits in children with BIF in verbal short-term memory, rapid naming, phonemic verbal fluency, and visual short-term memory, specifically in a visual recognition task, when compared with the control group. Long-term verbal memory was impaired only in older children with BIF and long-term visual memory showed no deficit. Verbal short-term memory stands out as a limitation and visual long-term memory as a strength. Correlations between the WISC-III and neuropsychological tests scores were predominantly low. The study expands the neuropsychological characterization of children with BIF and the implications of the deficits and strengths are stressed.

Visual search for changes in scenes creates long-term, incidental memory traces.

PubMed

Utochkin, Igor S; Wolfe, Jeremy M

2018-05-01

Humans are very good at remembering large numbers of scenes over substantial periods of time. But how good are they at remembering changes to scenes? In this study, we tested scene memory and change detection two weeks after initial scene learning. In Experiments 1-3, scenes were learned incidentally during visual search for change. In Experiment 4, observers explicitly memorized scenes. At test, after two weeks observers were asked to discriminate old from new scenes, to recall a change that they had detected in the study phase, or to detect a newly introduced change in the memorization experiment. Next, they performed a change detection task, usually looking for the same change as in the study period. Scene recognition memory was found to be similar in all experiments, regardless of the study task. In Experiment 1, more difficult change detection produced better scene memory. Experiments 2 and 3 supported a "depth-of-processing" account for the effects of initial search and change detection on incidental memory for scenes. Of most interest, change detection was faster during the test phase than during the study phase, even when the observer had no explicit memory of having found that change previously. This result was replicated in two of our three change detection experiments. We conclude that scenes can be encoded incidentally as well as explicitly and that changes in those scenes can leave measurable traces even if they are not explicitly recalled.

Effects of lexical competition on immediate memory span for spoken words.

PubMed

Goh, Winston D; Pisoni, David B

2003-08-01

Current theories and models of the structural organization of verbal short-term memory are primarily based on evidence obtained from manipulations of features inherent in the short-term traces of the presented stimuli, such as phonological similarity. In the present study, we investigated whether properties of the stimuli that are not inherent in the short-term traces of spoken words would affect performance in an immediate memory span task. We studied the lexical neighbourhood properties of the stimulus items, which are based on the structure and organization of words in the mental lexicon. The experiments manipulated lexical competition by varying the phonological neighbourhood structure (i.e., neighbourhood density and neighbourhood frequency) of the words on a test list while controlling for word frequency and intra-set phonological similarity (family size). Immediate memory span for spoken words was measured under repeated and nonrepeated sampling procedures. The results demonstrated that lexical competition only emerged when a nonrepeated sampling procedure was used and the participants had to access new words from their lexicons. These findings were not dependent on individual differences in short-term memory capacity. Additional results showed that the lexical competition effects did not interact with proactive interference. Analyses of error patterns indicated that item-type errors, but not positional errors, were influenced by the lexical attributes of the stimulus items. These results complement and extend previous findings that have argued for separate contributions of long-term knowledge and short-term memory rehearsal processes in immediate verbal serial recall tasks.

Attribution of movement: Potential links between subjective reports of agency and output monitoring.

PubMed

Sugimori, Eriko; Asai, Tomohisa

2015-01-01

According to agency memory theory, individuals decide whether "I did it" based on a memory trace of "I am doing it". The purpose of this study was to validate the agency memory theory. To this end, several hand actions were individually presented as samples, and participants were asked to perform the sample action, observe the performance of that action by another person, or imagine performing the action. Online feedback received by the participants during the action was manipulated among the different conditions, and output monitoring, in which participants were asked whether they had performed each hand action, was conducted. The rate at which respondents thought that they themselves had performed the action was higher when visual feedback was unaltered than when it was altered (Experiment 1A), and this tendency was observed across all types of altered feedback (Experiment 1B). The observation of an action performed by the hand of another person did not increase the rate at which respondents thought that they themselves had performed the action unless the participants actually did perform the action (Experiments 2A and 2B). In Experiment 3, a relationship was observed between the subjective feeling that "I am the one who is causing an action" and the memory that "I did perform the action". These experiments support the hypothesis that qualitative information and sense of "self" are tagged in a memory trace and that such tags can be used as cues for judgements when the memory is related to the "self".

Intervention strength does not differentially affect memory reconsolidation of strong memories.

PubMed

van Schie, Kevin; van Veen, Suzanne C; Hendriks, Yanniek R; van den Hout, Marcel A; Engelhard, Iris M

2017-10-01

Recently, it has become clear that retrieval (i.e., reactivation) of consolidated memories may return these memories into a labile state before they are restored into long-term memory ('reconsolidation'). Using behavioral manipulations, reactivated memories can be disrupted via the mechanism of novel learning. In the present study, we investigated whether changing a strong memory during reconsolidation depends on the strength of novel learning. To test this, participants (N=144) in six groups acquired a relatively strong memory on Day 1 by viewing and recalling a series of pictures three times. On Day 8, these pictures were reactivated in three groups, and they were not reactivated in the other three groups. Then, participants viewed and recalled new pictures once (weak new learning) or three times (strong new learning), or they did not learn any new pictures. On Day 9, participants performed a recognition test in which their memory for Day 1 pictures was assessed. Two main results are noted. First, the groups that reactivated pictures from Day 1 and received weak or strong new learning did not differ in memory performance. Second, these two groups consistently performed similar to groups that controlled for new learning without reactivation. Because these results contradict what was expected based on the reconsolidation hypothesis, we discuss possible explanations and implications. Copyright © 2017 Elsevier Inc. All rights reserved.

The Influence of Forward and Backward Associative Strength on False Recognition

ERIC Educational Resources Information Center

Arndt, Jason

2012-01-01

In an experiment, I examined the influence of 2 associative factors on false memory in the Deese-Roediger-McDermott paradigm (Deese, 1959; Roediger & McDermott, 1995): the strength of the association from studied items to unstudied lure items (backward associative strength, or BAS) and the strength of the association from unstudied lure items…

Studies of Trace Gas Chemical Cycles Using Inverse Methods and Global Chemical Transport Models

NASA Technical Reports Server (NTRS)

Prinn, Ronald G.

2003-01-01

We report progress in the first year, and summarize proposed work for the second year of the three-year dynamical-chemical modeling project devoted to: (a) development, testing, and refining of inverse methods for determining regional and global transient source and sink strengths for long lived gases important in ozone depletion and climate forcing, (b) utilization of inverse methods to determine these source/sink strengths using either MATCH (Model for Atmospheric Transport and Chemistry) which is based on analyzed observed wind fields or back-trajectories computed from these wind fields, (c) determination of global (and perhaps regional) average hydroxyl radical concentrations using inverse methods with multiple titrating gases, and (d) computation of the lifetimes and spatially resolved destruction rates of trace gases using 3D models. Important goals include determination of regional source strengths of methane, nitrous oxide, methyl bromide, and other climatically and chemically important biogenic/anthropogenic trace gases and also of halocarbons restricted by the Montreal protocol and its follow-on agreements and hydrohalocarbons now used as alternatives to the restricted halocarbons.

Awake, Offline Processing during Associative Learning

PubMed Central

Nestor, Adrian; Tarr, Michael J.; Creswell, J. David

2016-01-01

Offline processing has been shown to strengthen memory traces and enhance learning in the absence of conscious rehearsal or awareness. Here we evaluate whether a brief, two-minute offline processing period can boost associative learning and test a memory reactivation account for these offline processing effects. After encoding paired associates, subjects either completed a distractor task for two minutes or were immediately tested for memory of the pairs in a counterbalanced, within-subjects functional magnetic resonance imaging study. Results showed that brief, awake, offline processing improves memory for associate pairs. Moreover, multi-voxel pattern analysis of the neuroimaging data suggested reactivation of encoded memory representations in dorsolateral prefrontal cortex during offline processing. These results signify the first demonstration of awake, active, offline enhancement of associative memory and suggest that such enhancement is accompanied by the offline reactivation of encoded memory representations. PMID:27119345

Awake, Offline Processing during Associative Learning.

PubMed

Bursley, James K; Nestor, Adrian; Tarr, Michael J; Creswell, J David

2016-01-01

Offline processing has been shown to strengthen memory traces and enhance learning in the absence of conscious rehearsal or awareness. Here we evaluate whether a brief, two-minute offline processing period can boost associative learning and test a memory reactivation account for these offline processing effects. After encoding paired associates, subjects either completed a distractor task for two minutes or were immediately tested for memory of the pairs in a counterbalanced, within-subjects functional magnetic resonance imaging study. Results showed that brief, awake, offline processing improves memory for associate pairs. Moreover, multi-voxel pattern analysis of the neuroimaging data suggested reactivation of encoded memory representations in dorsolateral prefrontal cortex during offline processing. These results signify the first demonstration of awake, active, offline enhancement of associative memory and suggest that such enhancement is accompanied by the offline reactivation of encoded memory representations.

Auditory feedback blocks memory benefits of cueing during sleep

PubMed Central

Schreiner, Thomas; Lehmann, Mick; Rasch, Björn

2015-01-01

It is now widely accepted that re-exposure to memory cues during sleep reactivates memories and can improve later recall. However, the underlying mechanisms are still unknown. As reactivation during wakefulness renders memories sensitive to updating, it remains an intriguing question whether reactivated memories during sleep also become susceptible to incorporating further information after the cue. Here we show that the memory benefits of cueing Dutch vocabulary during sleep are in fact completely blocked when memory cues are directly followed by either correct or conflicting auditory feedback, or a pure tone. In addition, immediate (but not delayed) auditory stimulation abolishes the characteristic increases in oscillatory theta and spindle activity typically associated with successful reactivation during sleep as revealed by high-density electroencephalography. We conclude that plastic processes associated with theta and spindle oscillations occurring during a sensitive period immediately after the cue are necessary for stabilizing reactivated memory traces during sleep. PMID:26507814

[The pharmacology of memory (results and prospects)].

PubMed

Borodkin, Iu S; Zaĭtsev, Iu V

1984-07-01

Principal possibilities and limits of using the pharmacological approach for control of memory in studies of neurophysiological and neurochemical mechanisms of learning and memory in humans and animals are reviewed as well as its place in experimental and clinical therapy of memory disorders. Using an unspecific connector aethimizol as a pharmacological probe aided to assess changes accompanying the formation and consolidation of memory traces. The significance of fast and slow bioelectrical brain activity in the memory processing, the role of enzymes involved in transcription and template chromatine activity of the neurons under the effect of drugs on memory and learning, the correlation between time-depending learning and the pattern of RNA synthesis in brain cells, as well as possibilities and pathways of utilization of drugs in the correction of the long-term memory matrix formed by a stable pathological state of the brain, are discussed.

Neuropharmacology of memory consolidation and reconsolidation: Insights on central cholinergic mechanisms.

PubMed

Blake, M G; Krawczyk, M C; Baratti, C M; Boccia, M M

2014-01-01

Central cholinergic system is critically involved in all known memory processes. Endogenous acetylcholine release by cholinergic neurons is necessary for modulation of acquisition, encoding, consolidation, reconsolidation, extinction, retrieval and expression. Experiments from our laboratory are mainly focused on elucidating the mechanisms by which acetylcholine modulates memory processes. Blockade of hippocampal alpha-7-nicotinic receptors (α7-nAChRs) with the antagonist methyllycaconitine impairs memory reconsolidation. However, the administration of a α7-nAChR agonist (choline) produce a paradoxical modulation, causing memory enhancement in mice trained with a weak footshock, but memory impairment in animals trained with a strong footshock. All these effects are long-lasting, and depend on the age of the memory trace. This review summarizes and discusses some of our recent findings, particularly regarding the involvement of α7-nAChRs on memory reconsolidation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Susceptibility to declarative memory interference is pronounced in primary insomnia.

PubMed

Griessenberger, Hermann; Heib, Dominik P J; Lechinger, Julia; Luketina, Nikolina; Petzka, Marit; Moeckel, Tina; Hoedlmoser, Kerstin; Schabus, Manuel

2013-01-01

Sleep has been shown to stabilize memory traces and to protect against competing interference in both the procedural and declarative memory domain. Here, we focused on an interference learning paradigm by testing patients with primary insomnia (N = 27) and healthy control subjects (N = 21). In two separate experimental nights with full polysomnography it was revealed that after morning interference procedural memory performance (using a finger tapping task) was not impaired in insomnia patients while declarative memory (word pair association) was decreased following interference. More specifically, we demonstrate robust associations of central sleep spindles (in N3) with motor memory susceptibility to interference as well as (cortically more widespread) fast spindle associations with declarative memory susceptibility. In general the results suggest that insufficient sleep quality does not necessarily show up in worse overnight consolidation in insomnia but may only become evident (in the declarative memory domain) when interference is imposed.

Rewriting My Autobiography: The Legal and Ethical Implications of Memory-Dampening Agents

ERIC Educational Resources Information Center

Aoki, Cynthia R. A.

2008-01-01

The formation and recall of memories are fundamental aspects of life and help preserve the complex collection of experiences that provide us with a sense of identity and autonomy. Scientists have recently started to investigate pharmacological agents that inhibit or "dampen" the strength of memory formation and recall. The development of…

Recognition Decisions from Visual Working Memory Are Mediated by Continuous Latent Strengths

ERIC Educational Resources Information Center

Ricker, Timothy J.; Thiele, Jonathan E.; Swagman, April R.; Rouder, Jeffrey N.

2017-01-01

Making recognition decisions often requires us to reference the contents of working memory, the information available for ongoing cognitive processing. As such, understanding how recognition decisions are made when based on the contents of working memory is of critical importance. In this work we examine whether recognition decisions based on the…

Histone Acetylation is Recruited in Consolidation as a Molecular Feature of Stronger Memories

ERIC Educational Resources Information Center

Federman, Noel; Fustinana, Maria Sol; Romano, Arturo

2009-01-01

Gene expression is a key process for memory consolidation. Recently, the participation of epigenetic mechanisms like histone acetylation was evidenced in long-term memories. However, until now the training strength required and the persistence of the chromatin acetylation recruited are not well characterized. Here we studied whether histone…

RNG105/caprin1, an RNA granule protein for dendritic mRNA localization, is essential for long-term memory formation.

PubMed

Nakayama, Kei; Ohashi, Rie; Shinoda, Yo; Yamazaki, Maya; Abe, Manabu; Fujikawa, Akihiro; Shigenobu, Shuji; Futatsugi, Akira; Noda, Masaharu; Mikoshiba, Katsuhiko; Furuichi, Teiichi; Sakimura, Kenji; Shiina, Nobuyuki

2017-11-21

Local regulation of synaptic efficacy is thought to be important for proper networking of neurons and memory formation. Dysregulation of global translation influences long-term memory in mice, but the relevance of the regulation specific for local translation by RNA granules remains elusive. Here, we demonstrate roles of RNG105/caprin1 in long-term memory formation. RNG105 deletion in mice impaired synaptic strength and structural plasticity in hippocampal neurons. Furthermore, RNG105-deficient mice displayed unprecedentedly severe defects in long-term memory formation in spatial and contextual learning tasks. Genome-wide profiling of mRNA distribution in the hippocampus revealed an underlying mechanism: RNG105 deficiency impaired the asymmetric somato-dendritic localization of mRNAs. Particularly, RNG105 deficiency reduced the dendritic localization of mRNAs encoding regulators of AMPAR surface expression, which was consistent with attenuated homeostatic AMPAR scaling in dendrites and reduced synaptic strength. Thus, RNG105 has an essential role, as a key regulator of dendritic mRNA localization, in long-term memory formation.

Training-Dependent Associative Learning Induced Neocortical Structural Plasticity: A Trace Eyeblink Conditioning Analysis

PubMed Central

Chau, Lily S.; Prakapenka, Alesia V.; Zendeli, Liridon; Davis, Ashley S.; Galvez, Roberto

2014-01-01

Studies utilizing general learning and memory tasks have suggested the importance of neocortical structural plasticity for memory consolidation. However, these learning tasks typically result in learning of multiple different tasks over several days of training, making it difficult to determine the synaptic time course mediating each learning event. The current study used trace-eyeblink conditioning to determine the time course for neocortical spine modification during learning. With eyeblink conditioning, subjects are presented with a neutral, conditioned stimulus (CS) paired with a salient, unconditioned stimulus (US) to elicit an unconditioned response (UR). With multiple CS-US pairings, subjects learn to associate the CS with the US and exhibit a conditioned response (CR) when presented with the CS. Trace conditioning is when there is a stimulus free interval between the CS and the US. Utilizing trace-eyeblink conditioning with whisker stimulation as the CS (whisker-trace-eyeblink: WTEB), previous findings have shown that primary somatosensory (barrel) cortex is required for both acquisition and retention of the trace-association. Additionally, prior findings demonstrated that WTEB acquisition results in an expansion of the cytochrome oxidase whisker representation and synaptic modification in layer IV of barrel cortex. To further explore these findings and determine the time course for neocortical learning-induced spine modification, the present study utilized WTEB conditioning to examine Golgi-Cox stained neurons in layer IV of barrel cortex. Findings from this study demonstrated a training-dependent spine proliferation in layer IV of barrel cortex during trace associative learning. Furthermore, findings from this study showing that filopodia-like spines exhibited a similar pattern to the overall spine density further suggests that reorganization of synaptic contacts set the foundation for learning-induced neocortical modifications through the different neocortical layers. PMID:24760074

The Presence of the Past: Using Memory Work To Search for Psychological Traces of the Nazi Past in Contemporary Germans.

ERIC Educational Resources Information Center

Neumann, Wolfgang

2002-01-01

Examines how far traces of the Nazi past can still be found in the psychological family environment of college students attending a counseling center two generations after the end of World War II. Reveals that failure to discuss such topics within families was of decisive significance during counseling sessions, and that current problems often…

Exploiting Data Similarity to Reduce Memory Footprints

DTIC Science & Technology

2011-01-01

leslie3d Fortran Computational Fluid Dynamics (CFD) application 122. tachyon C Parallel Ray Tracing application 128.GAPgeofem C and Fortran Simulates...benefits most from SBLLmalloc; LAMMPS, which shows moderate similarity from primarily zero pages; and 122. tachyon , a parallel ray- tracing application...similarity across MPI tasks. They primarily are zero- pages although a small fraction (≈10%) are non-zero pages. 122. tachyon is an image rendering

Nonword Repetition Priming in Lexical Decision Reverses as a Function of Study Task and Speed Stress

ERIC Educational Resources Information Center

Zeelenberg, Rene; Wagenmakers, Eric-Jan; Shiffrin, Richard M.

2004-01-01

The authors argue that nonword repetition priming in lexical decision is the net result of 2 opposing processes. First, repeating nonwords in the lexical decision task results in the storage of a memory trace containing the interpretation that the letter string is a nonword; retrieval of this trace leads to an increase in performance for repeated…

Memory monitoring by animals and humans

NASA Technical Reports Server (NTRS)

Smith, J. D.; Shields, W. E.; Allendoerfer, K. R.; Washburn, D. A.; Rumbaugh, D. M. (Principal Investigator)

1998-01-01

The authors asked whether animals and humans would use similarly an uncertain response to escape indeterminate memories. Monkeys and humans performed serial probe recognition tasks that produced differential memory difficulty across serial positions (e.g., primacy and recency effects). Participants were given an escape option that let them avoid any trials they wished and receive a hint to the trial's answer. Across species, across tasks, and even across conspecifics with sharper or duller memories, monkeys and humans used the escape option selectively when more indeterminate memory traces were probed. Their pattern of escaping always mirrored the pattern of their primary memory performance across serial positions. Signal-detection analyses confirm the similarity of the animals' and humans' performances. Optimality analyses assess their efficiency. Several aspects of monkeys' performance suggest the cognitive sophistication of their decisions to escape.

Influences of Appearance-Behavior Congruity on Memory and Social Judgments

PubMed Central

Cassidy, Brittany S.; Gutchess, Angela H.

2014-01-01

Prior work shows that appearance-behavior congruity impacts memory and evaluations. Building upon prior work, we assessed influences of appearance-behavior congruity on source memory and judgment strength to illustrate ways congruity effects permeate social cognition. We paired faces varying on trustworthiness with valenced behaviors to create congruent and incongruent face-behavior pairs. Young and older adults remembered congruent pairs better than incongruent, but both were remembered better than pairs with faces rated average in appearance. This suggests that multiple, even conflicting, valenced cues improve memory over receiving fewer cues. Consistent with our manipulation of facial trustworthiness, congruity effects were present in the strength of trustworthiness-related but not dominance judgments. Subtle age differences emerged in congruity effects when learning about others, with older adults showing effects for approach judgments given both high and low arousal behaviors. Young adults had congruity effects for approach, prosociality, and trustworthiness judgments, given high arousal behaviors only. These findings deepen our understanding of how appearance-behavior congruity impacts memory for and evaluations of others. PMID:25180615

Influences of appearance-behaviour congruity on memory and social judgements.

PubMed

Cassidy, Brittany S; Gutchess, Angela H

2015-01-01

Prior work shows that appearance-behaviour congruity impacts memory and evaluations. Building upon prior work, we assessed influences of appearance-behaviour congruity on source memory and judgement strength to illustrate ways congruity effects permeate social cognition. We paired faces varying on trustworthiness with valenced behaviours to create congruent and incongruent face-behaviour pairs. Young and older adults remembered congruent pairs better than incongruent, but both were remembered better than pairs with faces rated average in appearance. This suggests that multiple, even conflicting, valenced cues improve memory over receiving fewer cues. Consistent with our manipulation of facial trustworthiness, congruity effects were present in the strength of trustworthiness-related but not dominance judgements. Subtle age differences emerged in congruity effects when learning about others, with older adults showing effects for approach judgements given both high and low arousal behaviours. Young adults had congruity effects for approach, prosociality and trustworthiness judgements, given high arousal behaviours only. These findings deepen our understanding of how appearance-behaviour congruity impacts memory for and evaluations of others.

Memory as behavior: The importance of acquisition and remembering strategies

PubMed Central

Delaney, Peter F.; Austin, John

1998-01-01

The study of memory has traditionally been the province of cognitive psychology, which has postulated different memory systems that store memory traces to explain remembering. Behavioral psychologists have been unsuccessful at empirically identifying the behavior that occurs during remembering because so much of it occurs rapidly and covertly. In addition, behavior analysts have generally been disinterested in studying transient phenomena such as memory. As a result, the cognitive interpretation has been the only one that has made and tested useful predictions. Recent experimental evidence acquired while having participants “think aloud” suggests that a behavioral approach to memory may provide a superior account of memory performance and allow applied scientists to observe and modify memory-related behavior with well-known applied behavior-analytic techniques. We review evidence supporting and extending the interpretation of memory provided by Palmer (1991), who described memory in terms of precurrent behavior that occurs at the time of acquisition in preparation for problem solving that occurs at the time of remembering. ImagesFig. 1 PMID:22477129

Statistical Computations Underlying the Dynamics of Memory Updating

PubMed Central

Gershman, Samuel J.; Radulescu, Angela; Norman, Kenneth A.; Niv, Yael

2014-01-01

Psychophysical and neurophysiological studies have suggested that memory is not simply a carbon copy of our experience: Memories are modified or new memories are formed depending on the dynamic structure of our experience, and specifically, on how gradually or abruptly the world changes. We present a statistical theory of memory formation in a dynamic environment, based on a nonparametric generalization of the switching Kalman filter. We show that this theory can qualitatively account for several psychophysical and neural phenomena, and present results of a new visual memory experiment aimed at testing the theory directly. Our experimental findings suggest that humans can use temporal discontinuities in the structure of the environment to determine when to form new memory traces. The statistical perspective we offer provides a coherent account of the conditions under which new experience is integrated into an old memory versus forming a new memory, and shows that memory formation depends on inferences about the underlying structure of our experience. PMID:25375816

The role of sleep in cognitive processing: focusing on memory consolidation.

PubMed

Chambers, Alexis M

2017-05-01

Research indicates that sleep promotes various cognitive functions, such as decision-making, language, categorization, and memory. Of these, most work has focused on the influence of sleep on memory, with ample work showing that sleep enhances memory consolidation, a process that stores new memories in the brain over time. Recent psychological and neurophysiological research has vastly increased understanding of this process. Such work not only suggests that consolidation relies on plasticity-related mechanisms that reactivate and stabilize memory representations, but also that this process may be experimentally manipulated by methods that target which memory traces are reactivated during sleep. Furthermore, aside from memory storage capabilities, memory consolidation also appears to reorganize and integrate memories with preexisting knowledge, which may facilitate the discovery of underlying rules and associations that benefit other cognitive functioning, including problem solving and creativity. WIREs Cogn Sci 2017, 8:e1433. doi: 10.1002/wcs.1433 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

Methods for Assessment of Memory Reactivation.

PubMed

Liu, Shizhao; Grosmark, Andres D; Chen, Zhe

2018-04-13

It has been suggested that reactivation of previously acquired experiences or stored information in declarative memories in the hippocampus and neocortex contributes to memory consolidation and learning. Understanding memory consolidation depends crucially on the development of robust statistical methods for assessing memory reactivation. To date, several statistical methods have seen established for assessing memory reactivation based on bursts of ensemble neural spike activity during offline states. Using population-decoding methods, we propose a new statistical metric, the weighted distance correlation, to assess hippocampal memory reactivation (i.e., spatial memory replay) during quiet wakefulness and slow-wave sleep. The new metric can be combined with an unsupervised population decoding analysis, which is invariant to latent state labeling and allows us to detect statistical dependency beyond linearity in memory traces. We validate the new metric using two rat hippocampal recordings in spatial navigation tasks. Our proposed analysis framework may have a broader impact on assessing memory reactivations in other brain regions under different behavioral tasks.

Fifty years since Lashley's In search of the Engram: refutations and conjectures.

PubMed

Bruce, D

2001-12-01

In his well-known article 'In Search of the Engram' published in 1950, Karl Spencer Lashley summarized his 33 years of research and theory on memory and the brain. He concluded that (1) memories are not localized but are instead distributed within functional areas of the cortex and (2) memory traces are not isolated cortical connections between inputs and outputs. Though not the first time he had expressed such convictions, their reiteration in this article was backed by Lashley's estimable reputation and expressive power and they have taken firm root in the collective knowledge of today's memory and neuropsychological research community.

Working memory for braille is shaped by experience

PubMed Central

Scherzer, Peter; Viau, Robert; Voss, Patrice; Lepore, Franco

2011-01-01

Tactile working memory was found to be more developed in completely blind (congenital and acquired) than in semi-sighted subjects, indicating that experience plays a crucial role in shaping working memory. A model of working memory, adapted from the classical model proposed by Baddeley and Hitch1 and Baddeley2 is presented where the connection strengths of a highly cross-modal network are altered through experience. PMID:21655448

Dynorphins regulate the strength of social memory.

PubMed

Bilkei-Gorzo, A; Mauer, D; Michel, K; Zimmer, A

2014-02-01

Emotionally arousing events like encounter with an unfamiliar con-species produce strong and vivid memories, whereby the hippocampus and amygdala play a crucial role. It is less understood, however, which neurotransmitter systems regulate the strength of social memories, which have a strong emotional component. It was shown previously that dynorphin signalling is involved in the formation and extinction of fear memories, therefore we asked if it influences social memories as well. Mice with a genetic deletion of the prodynorphin gene Pdyn (Pdyn(-/-)) showed a superior partner recognition ability, whereas their performance in the object recognition test was identical as in wild-type mice. Pharmacological blockade of kappa opioid receptors (KORs) led to an enhanced social memory in wild-type animals, whereas activation of KORs reduced the recognition ability of Pdyn(-/-) mice. Partner recognition test situation induced higher elevation in dynorphin A levels in the central and basolateral amygdala as well as in the hippocampus, and also higher dynorphin B levels in the hippocampus than the object recognition test situation. Our result suggests that dynorphin system activity is increased in emotionally arousing situation and it decreases the formation of social memories. Thus, dynorphin signalling is involved in the formation of social memories by diminishing the emotional component of the experience. Copyright © 2013 Elsevier Ltd. All rights reserved.

The effect of the social regulation of emotion on emotional long-term memory.

PubMed

Flores, Luis E; Berenbaum, Howard

2017-04-01

Memories for emotional events tend to be stronger than for neutral events, and weakening negative memories can be helpful to promote well-being. The present study examined whether the social regulation of emotion (in the form of handholding) altered the strength of emotional long-term memory. A sample of 219 undergraduate students viewed sets of negative, neutral, and positive images. Each participant held a stress ball while viewing half of the images and held someone's hand while viewing the other half. Participants returned 1 week later to complete a recognition task. Performance on the recognition task demonstrated that participants had lower memory accuracy for negative but not for positive pictures that were shown while they were holding someone's hand compared with when they were holding a stress ball. Although handholding altered the strength of negative emotional long-term memory, it did not down-regulate negative affective response as measured by self-report or facial expressivity. The present findings provide evidence that the social regulation of emotion can help weaken memory for negative information. Given the role of strong negative memories in different forms of psychopathology (e.g., depression, posttraumatic stress disorder), these findings may help better understand how close relationships protect against psychopathology. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Semantic processes leading to true and false memory formation in schizophrenia.

PubMed

Paz-Alonso, Pedro M; Ghetti, Simona; Ramsay, Ian; Solomon, Marjorie; Yoon, Jong; Carter, Cameron S; Ragland, J Daniel

2013-07-01

Encoding semantic relationships between items on word lists (semantic processing) enhances true memories, but also increases memory distortions. Episodic memory impairments in schizophrenia (SZ) are strongly driven by failures to process semantic relations, but the exact nature of these relational semantic processing deficits is not well understood. Here, we used a false memory paradigm to investigate the impact of implicit and explicit semantic processing manipulations on episodic memory in SZ. Thirty SZ and 30 demographically matched healthy controls (HC) studied Deese/Roediger-McDermott (DRM) lists of semantically associated words. Half of the lists had strong implicit semantic associations and the remainder had low strength associations. Similarly, half of the lists were presented under "standard" instructions and the other half under explicit "relational processing" instructions. After study, participants performed recall and old/new recognition tests composed of targets, critical lures, and unrelated lures. HC exhibited higher true memories and better discriminability between true and false memory compared to SZ. High, versus low, associative strength increased false memory rates in both groups. However, explicit "relational processing" instructions positively improved true memory rates only in HC. Finally, true and false memory rates were associated with severity of disorganized and negative symptoms in SZ. These results suggest that reduced processing of semantic relationships during encoding in SZ may stem from an inability to implement explicit relational processing strategies rather than a fundamental deficit in the implicit activation and retrieval of word meanings from patients' semantic lexicon. Copyright © 2013 Elsevier B.V. All rights reserved.

The effect of mild acute stress during memory consolidation on emotional recognition memory.

PubMed

Corbett, Brittany; Weinberg, Lisa; Duarte, Audrey

2017-11-01

Stress during consolidation improves recognition memory performance. Generally, this memory benefit is greater for emotionally arousing stimuli than neutral stimuli. The strength of the stressor also plays a role in memory performance, with memory performance improving up to a moderate level of stress and thereafter worsening. As our daily stressors are generally minimal in strength, we chose to induce mild acute stress to determine its effect on memory performance. In the current study, we investigated if mild acute stress during consolidation improves memory performance for emotionally arousing images. To investigate this, we had participants encode highly arousing negative, minimally arousing negative, and neutral images. We induced stress using the Montreal Imaging Stress Task (MIST) in half of the participants and a control task to the other half of the participants directly after encoding (i.e. during consolidation) and tested recognition 48h later. We found no difference in memory performance between the stress and control group. We found a graded pattern among confidence, with responders in the stress group having the least amount of confidence in their hits and controls having the most. Across groups, we found highly arousing negative images were better remembered than minimally arousing negative or neutral images. Although stress did not affect memory accuracy, responders, as defined by cortisol reactivity, were less confident in their decisions. Our results suggest that the daily stressors humans experience, regardless of their emotional affect, do not have adverse effects on memory. Copyright © 2017 Elsevier Inc. All rights reserved.

Preventing the return of fear memories with postretrieval extinction: A human study using a burst of white noise as an aversive stimulus.

PubMed

Fernandez-Rey, Jose; Gonzalez-Gonzalez, Daniel; Redondo, Jaime

2018-06-07

Standard extinction procedures seem to imply an inhibition of the fear response, but not a modification of the original fear-memory trace, which remains intact (Bouton, 2002, 2004). Typically, the behavioral procedure used to modify this trace is the so-called postretrieval extinction, consisting of fear-memory reactivation followed by extinction applied within the reconsolidation window. However, the application of this technique yields mixed results, probably due to a series of boundary conditions that limit the effectiveness of postretrieval-extinction effects. In this study a number of potential, and hitherto unexplored, moderators of such effects are considered. Using an interval of 48 hr between extinction and re-extinction, the findings show a spontaneous recovery similar to that found in studies that use a 24-hr interval. Also, the use of intervals of 10 and 20 min between reactivation and extinction led to a similar fear return. Finally, the burst of white noise used as an unconditioned stimulus (US) here was shown to be as effective as the electric shock normally used in the study of fear-memory reconsolidation. These findings suggest that postretrieval extinction is an effective behavioral technique for modifying the original fear memory and for the elimination of the fear return. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Corticosterone administration after a single-trial contextual fear conditioning does not influence the strength and specificity of recent and remote memory in rats.

PubMed

Bueno, Ana Paula A; de Paiva, Joselisa Péres Queiroz; Corrêa, Moisés Dos Santos; Tiba, Paula Ayako; Fornari, Raquel Vecchio

2017-03-15

It is well established that corticosterone (CORT) enhances memory consolidation of emotionally arousing experiences. Despite emotional memories being usually referred to as well remembered for long periods, there are no studies that have investigated the effects of CORT in modulating the duration and specificity of memory. In the present study, we trained Wistar rats in a single-trial contextual fear conditioning protocol and injected CORT (0.3, 1.0 or 3.0mg/kg), immediately after training, to investigate its effects on memory consolidation. Rats were tested 2 and 29days after the training session or only 29days after training to assess recent or remote memory. Our results show that animals tested for recent memory discriminated the training context from a novel one, while those tested only for remote memory generalized the fear response to both contexts. Animals tested for remote memory after being tested for recent memory were able to discriminate both contexts. These results support the literature regarding memory specificity and duration. However, CORT treatment, even at the dose of 1.0mg/kg that effectively enhanced the plasmatic hormone levels, did not affect the strength or the specificity of memory in either recent or remote memory tests. We hypothesize that the lack of effect of CORT treatment could be due to the low arousing training experience of the single-trial protocol which, despite being sufficient to induce significant recent and remote memory consolidation, may not be sufficient to allow the memory-enhancing effect of CORT. Copyright © 2017 Elsevier Inc. All rights reserved.

Time-Based Loss in Visual Short-Term Memory Is from Trace Decay, Not Temporal Distinctiveness

ERIC Educational Resources Information Center

Ricker, Timothy J.; Spiegel, Lauren R.; Cowan, Nelson

2014-01-01

There is no consensus as to why forgetting occurs in short-term memory tasks. In past work, we have shown that forgetting occurs with the passage of time, but there are 2 classes of theories that can explain this effect. In the present work, we investigate the reason for time-based forgetting by contrasting the predictions of temporal…

Explaining Variance in Long-Term Recall in 3- and 4-Year-Old Children: The Importance of Post-Encoding Processes

ERIC Educational Resources Information Center

Bauer, Patricia J.; Larkina, Marina; Doydum, Ayzit O.

2012-01-01

Long-term recall is influenced by what originally was encoded as well as by the efficacy of retrieval processes. The possible explanatory role of post-encoding processes by which initially labile memory traces are stabilized and integrated into long-term memory (i.e., consolidated) has received relatively less research attention. In the current…

Synaptic and nonsynaptic plasticity approximating probabilistic inference

PubMed Central

Tully, Philip J.; Hennig, Matthias H.; Lansner, Anders

2014-01-01

Learning and memory operations in neural circuits are believed to involve molecular cascades of synaptic and nonsynaptic changes that lead to a diverse repertoire of dynamical phenomena at higher levels of processing. Hebbian and homeostatic plasticity, neuromodulation, and intrinsic excitability all conspire to form and maintain memories. But it is still unclear how these seemingly redundant mechanisms could jointly orchestrate learning in a more unified system. To this end, a Hebbian learning rule for spiking neurons inspired by Bayesian statistics is proposed. In this model, synaptic weights and intrinsic currents are adapted on-line upon arrival of single spikes, which initiate a cascade of temporally interacting memory traces that locally estimate probabilities associated with relative neuronal activation levels. Trace dynamics enable synaptic learning to readily demonstrate a spike-timing dependence, stably return to a set-point over long time scales, and remain competitive despite this stability. Beyond unsupervised learning, linking the traces with an external plasticity-modulating signal enables spike-based reinforcement learning. At the postsynaptic neuron, the traces are represented by an activity-dependent ion channel that is shown to regulate the input received by a postsynaptic cell and generate intrinsic graded persistent firing levels. We show how spike-based Hebbian-Bayesian learning can be performed in a simulated inference task using integrate-and-fire (IAF) neurons that are Poisson-firing and background-driven, similar to the preferred regime of cortical neurons. Our results support the view that neurons can represent information in the form of probability distributions, and that probabilistic inference could be a functional by-product of coupled synaptic and nonsynaptic mechanisms operating over several timescales. The model provides a biophysical realization of Bayesian computation by reconciling several observed neural phenomena whose functional effects are only partially understood in concert. PMID:24782758

An Associative-Activation Theory of Children's and Adults' Memory Illusions

ERIC Educational Resources Information Center

Howe, Mark L.; Wimmer, Marina C.; Gagnon, Nadine; Plumpton, Shannon

2009-01-01

The effects of associative strength and gist relations on rates of children's and adults' true and false memories were examined in three experiments. Children aged 5-11 and university-aged adults participated in a standard Deese/Roediger-McDermott false memory task using DRM and category lists in two experiments and in the third, children…

Item Strength Influences Source Confidence and Alters Source Memory zROC Slopes

ERIC Educational Resources Information Center

Starns, Jeffrey J.; Ksander, John C.

2016-01-01

Increasing the number of study trials creates a crossover pattern in source memory zROC slopes; that is, the slope is either below or above 1 depending on which source receives stronger learning. This pattern can be produced if additional learning affects memory processes such as the relative contribution of recollection and familiarity to source…

Testing Signal-Detection Models of Yes/No and Two-Alternative Forced-Choice Recognition Memory

ERIC Educational Resources Information Center

Jang, Yoonhee; Wixted, John T.; Huber, David E.

2009-01-01

The current study compared 3 models of recognition memory in their ability to generalize across yes/no and 2-alternative forced-choice (2AFC) testing. The unequal-variance signal-detection model assumes a continuous memory strength process. The dual-process signal-detection model adds a thresholdlike recollection process to a continuous…

[Influence of activation and blockade of NMDA receptors on extinction of passive avoidance response in mice with different levels of anxiety].

PubMed

Tomilenko, R A; Dubrovina, N I

2006-03-01

Influence of agonist (D-cycloserine) and antagonist (dizocilpine) N-methyl-D-aspartate receptors on learning and extinction of passive avoidance response in medium-, high-, and low-anxious mice was studied. In medium-anxious mice, D-cycloserine (30 mg/kg) although not changing learning accelerated development of extinction, whereas dizocilpine (0.15 mg/kg), while impairing passive avoidance learning, detained the extinction. In high-anxious mice with good retrieval of memory trace and absence of extinction, D-cycloserine was ineffective, whereas dizocilpine reduced learning and promoted retention of memory trace retrieval at the generated level on extinction. In low-anxious mice, D-cycloserine impaired learning and accelerated extinction, whereas dizocilpine completely blocked learning and retention of passive avoidance response.

Not all order memory is equal: Test demands reveal dissociations in memory for sequence information.

PubMed

Jonker, Tanya R; MacLeod, Colin M

2017-02-01

Remembering the order of a sequence of events is a fundamental feature of episodic memory. Indeed, a number of formal models represent temporal context as part of the memory system, and memory for order has been researched extensively. Yet, the nature of the code(s) underlying sequence memory is still relatively unknown. Across 4 experiments that manipulated encoding task, we found evidence for 3 dissociable facets of order memory. Experiment 1 introduced a test requiring a judgment of which of 2 alternatives had immediately followed a word during encoding. This measure revealed better retention of interitem associations following relational encoding (silent reading) than relatively item-specific encoding (judging referent size), a pattern consistent with that observed in previous research using order reconstruction tests. In sharp contrast, Experiment 2 demonstrated the reverse pattern: Memory for the studied order of 2 sequentially presented items was actually better following item-specific encoding than following relational encoding. Experiment 3 reproduced this dissociation in a single experiment using both tests. Experiment 4 extended these findings by further dissociating the roles of relational encoding and item strength in the 2 tests. Taken together, these results indicate that memory for event sequence is influenced by (a) interitem associations, (b) the emphasized directionality of an association, and (c) an item's strength independent of other items. Memory for order is more complicated than has been portrayed in theories of memory and its nuances should be carefully considered when designing tests and models of temporal and relational memory. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Silent memory engrams as the basis for retrograde amnesia

PubMed Central

Roy, Dheeraj S.; Muralidhar, Shruti; Smith, Lillian M.

2017-01-01

Recent studies identified neuronal ensembles and circuits that hold specific memory information (memory engrams). Memory engrams are retained under protein synthesis inhibition-induced retrograde amnesia. These engram cells can be activated by optogenetic stimulation for full-fledged recall, but not by stimulation using natural recall cues (thus, amnesia). We call this state of engrams “silent engrams” and the cells bearing them “silent engram cells.” The retention of memory information under amnesia suggests that the time-limited protein synthesis following learning is dispensable for memory storage, but may be necessary for effective memory retrieval processes. Here, we show that the full-fledged optogenetic recall persists at least 8 d after learning under protein synthesis inhibition-induced amnesia. This long-term retention of memory information correlates with equally persistent retention of functional engram cell-to-engram cell connectivity. Furthermore, inactivation of the connectivity of engram cell ensembles with its downstream counterparts, but not upstream ones, prevents optogenetic memory recall. Consistent with the previously reported lack of retention of augmented synaptic strength and reduced spine density in silent engram cells, optogenetic memory recall under amnesia is stimulation strength-dependent, with low-power stimulation eliciting only partial recall. Finally, the silent engram cells can be converted to active engram cells by overexpression of α-p-21–activated kinase 1, which increases spine density in engram cells. These results indicate that memory information is retained in a form of silent engram under protein synthesis inhibition-induced retrograde amnesia and support the hypothesis that memory is stored as the specific connectivity between engram cells. PMID:29078397

Silent memory engrams as the basis for retrograde amnesia.

PubMed

Roy, Dheeraj S; Muralidhar, Shruti; Smith, Lillian M; Tonegawa, Susumu

2017-11-14

Recent studies identified neuronal ensembles and circuits that hold specific memory information (memory engrams). Memory engrams are retained under protein synthesis inhibition-induced retrograde amnesia. These engram cells can be activated by optogenetic stimulation for full-fledged recall, but not by stimulation using natural recall cues (thus, amnesia). We call this state of engrams "silent engrams" and the cells bearing them "silent engram cells." The retention of memory information under amnesia suggests that the time-limited protein synthesis following learning is dispensable for memory storage, but may be necessary for effective memory retrieval processes. Here, we show that the full-fledged optogenetic recall persists at least 8 d after learning under protein synthesis inhibition-induced amnesia. This long-term retention of memory information correlates with equally persistent retention of functional engram cell-to-engram cell connectivity. Furthermore, inactivation of the connectivity of engram cell ensembles with its downstream counterparts, but not upstream ones, prevents optogenetic memory recall. Consistent with the previously reported lack of retention of augmented synaptic strength and reduced spine density in silent engram cells, optogenetic memory recall under amnesia is stimulation strength-dependent, with low-power stimulation eliciting only partial recall. Finally, the silent engram cells can be converted to active engram cells by overexpression of α-p-21-activated kinase 1, which increases spine density in engram cells. These results indicate that memory information is retained in a form of silent engram under protein synthesis inhibition-induced retrograde amnesia and support the hypothesis that memory is stored as the specific connectivity between engram cells.

False memories with age: neural and cognitive underpinnings

PubMed Central

Devitt, Aleea L.; Schacter, Daniel L.

2016-01-01

As we age we become increasingly susceptible to memory distortions and inaccuracies. Over the past decade numerous neuroimaging studies have attempted to illuminate the neural underpinnings of aging and false memory. Here we review these studies, and link their findings with those concerning the cognitive properties of age-related changes in memory accuracy. Collectively this evidence points towards a prominent role for age-related declines in medial temporal and prefrontal brain areas, and corresponding impairments in associative binding and strategic monitoring. A resulting cascade of cognitive changes contributes to the heightened vulnerability to false memories with age, including reduced recollective ability, a reliance on gist information and familiarity-based monitoring mechanisms, as well as a reduced ability to inhibit irrelevant information and erroneous binding of features between memory traces. We consider both theoretical and applied implications of research on aging and false memories, as well as questions remaining to be addressed in future research. PMID:27592332

The influence of aging on attentional refreshing and articulatory rehearsal during working memory on later episodic memory performance.

PubMed

Loaiza, Vanessa M; McCabe, David P

2013-01-01

We investigated age-related changes in two proposed mechanisms of maintenance in working memory, articulatory rehearsal, and attentional refreshing, by examining the consequences of manipulating the opportunity for each on delayed recall. Both experiments utilized modified operation span tasks to vary the opportunity for articulatory rehearsal (Experiment 1) and attentional refreshing opportunities (Experiment 2). In both experiments, episodic memory was tested for items that had been initially studied during the respective operation span task. Older adults' episodic memory benefited less from opportunities for refreshing than younger adults. In contrast, articulatory rehearsal opportunities did not influence episodic memory for either age group. The results suggest that attentional refreshing, and not articulatory rehearsal, is important during working memory in order to bind more accessible traces at later tests, which appears to be more deficient in older adults than younger adults.

TMS-induced neural noise in sensory cortex interferes with short-term memory storage in prefrontal cortex.

PubMed

Bancroft, Tyler D; Hogeveen, Jeremy; Hockley, William E; Servos, Philip

2014-01-01

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.'s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature.

Impairing existing declarative memory in humans by disrupting reconsolidation

PubMed Central

Chan, Jason C. K.; LaPaglia, Jessica A.

2013-01-01

During the past decade, a large body of research has shown that memory traces can become labile upon retrieval and must be restabilized. Critically, interrupting this reconsolidation process can abolish a previously stable memory. Although a large number of studies have demonstrated this reconsolidation associated amnesia in nonhuman animals, the evidence for its occurrence in humans is far less compelling, especially with regard to declarative memory. In fact, reactivating a declarative memory often makes it more robust and less susceptible to subsequent disruptions. Here we show that existing declarative memories can be selectively impaired by using a noninvasive retrieval–relearning technique. In six experiments, we show that this reconsolidation-associated amnesia can be achieved 48 h after formation of the original memory, but only if relearning occurred soon after retrieval. Furthermore, the amnesic effect persists for at least 24 h, cannot be attributed solely to source confusion and is attainable only when relearning targets specific existing memories for impairment. These results demonstrate that human declarative memory can be selectively rewritten during reconsolidation. PMID:23690586

Context odor presentation during sleep enhances memory in honeybees.

PubMed

Zwaka, Hanna; Bartels, Ruth; Gora, Jacob; Franck, Vivien; Culo, Ana; Götsch, Moritz; Menzel, Randolf

2015-11-02

Sleep plays an important role in stabilizing new memory traces after learning [1-3]. Here we investigate whether sleep's role in memory processing is similar in evolutionarily distant species and demonstrate that a context trigger during deep-sleep phases improves memory in invertebrates, as it does in humans. We show that in honeybees (Apis mellifera), exposure to an odor during deep sleep that has been present during learning improves memory performance the following day. Presentation of the context odor during wake phases or novel odors during sleep does not enhance memory. In humans, memory consolidation can be triggered by presentation of a context odor during slow-wave sleep that had been present during learning [3-5]. Our results reveal that deep-sleep phases in honeybees have the potential to prompt memory consolidation, just as they do in humans. This study provides strong evidence for a conserved role of sleep-and how it affects memory processes-from insects to mammals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accurate low-cost methods for performance evaluation of cache memory systems

NASA Technical Reports Server (NTRS)

Laha, Subhasis; Patel, Janak H.; Iyer, Ravishankar K.

1988-01-01

Methods of simulation based on statistical techniques are proposed to decrease the need for large trace measurements and for predicting true program behavior. Sampling techniques are applied while the address trace is collected from a workload. This drastically reduces the space and time needed to collect the trace. Simulation techniques are developed to use the sampled data not only to predict the mean miss rate of the cache, but also to provide an empirical estimate of its actual distribution. Finally, a concept of primed cache is introduced to simulate large caches by the sampling-based method.

The neurobiology of consolidations, or, how stable is the engram?

PubMed

Dudai, Yadin

2004-01-01

Consolidation is the progressive postacquisition stabilization of long-term memory. The term is commonly used to refer to two types of processes: synaptic consolidation, which is accomplished within the first minutes to hours after learning and occurs in all memory systems studied so far; and system consolidation, which takes much longer, and in which memories that are initially dependent upon the hippocampus undergo reorganization and may become hippocampal-independent. The textbook account of consolidation is that for any item in memory, consolidation starts and ends just once. Recently, a heated debate has been revitalized on whether this is indeed the case, or, alternatively, whether memories become labile and must undergo some form of renewed consolidation every time they are activated. This debate focuses attention on fundamental issues concerning the nature of the memory trace, its maturation, persistence, retrievability, and modifiability.

Fatigue design curve of a TiNi/Al shape memory alloy composite for aircraft stringer design

NASA Astrophysics Data System (ADS)

Park, Young-Chul; Jo, Young-Jik; Baek, Seok-Heum; Furuya, Yasubumi

2009-05-01

In this study, a TiNi/Al6061 shape memory alloy (SMA) composite was fabricated by the hot press method, and pressed by a roller for its strength improvement using the shape memory fiber shrinkage phenomenon. These two kinds of specimens were fabricated with 0% and 5% volume ratio and 0%, 10 % and 20% reduction ratio of TiNi alloy fiber, respectively. A fatigue test has been performed to evaluate the fatigue life for the fabricated TiNi/Al SMA composite as an S-N curve. The results from the Goodman diagram is able to illustrate the failure criterion and fatigue limit between tensile and bending fatigue strength in the fatigue characterization of TiNi/Al SMA composites.

No Evidence for Memory Decontextualization across One Night of Sleep

PubMed Central

Jurewicz, Katarzyna; Cordi, Maren Jasmin; Staudigl, Tobias; Rasch, Björn

2016-01-01

Sleep after learning strengthens memory consolidation. According to the active system consolidation hypothesis, sleep supports the integration of newly acquired memories into cortical knowledge networks, presumably accompanied by a process of decontextualization of the memory trace (i.e., a gradual loss of memory for the learning context). However, the availability of contextual information generally facilitates memory recall and studies on the interaction of sleep and context on memory retrieval have revealed inconsistent results. Here, we do not find any evidence for a role of sleep in the decontextualization of newly learned declarative memories. In two separate studies, 104 healthy young adults incidentally learned words associated with a context. After a 12 h retention interval filled with either sleep or wakefulness, recall (Experiment 1) or recognition (Experiment 2) was tested with the same or different context. Overall, memory retrieval was significantly improved when the learning context was reinstated, as compared to a different context. However, this context effect of memory was not modulated by sleep vs. wakefulness. These findings argue against a decontextualization of memories, at least across a single night of sleep. PMID:26858622

Experience-Driven Formation of Parts-Based Representations in a Model of Layered Visual Memory

PubMed Central

Jitsev, Jenia; von der Malsburg, Christoph

2009-01-01

Growing neuropsychological and neurophysiological evidence suggests that the visual cortex uses parts-based representations to encode, store and retrieve relevant objects. In such a scheme, objects are represented as a set of spatially distributed local features, or parts, arranged in stereotypical fashion. To encode the local appearance and to represent the relations between the constituent parts, there has to be an appropriate memory structure formed by previous experience with visual objects. Here, we propose a model how a hierarchical memory structure supporting efficient storage and rapid recall of parts-based representations can be established by an experience-driven process of self-organization. The process is based on the collaboration of slow bidirectional synaptic plasticity and homeostatic unit activity regulation, both running at the top of fast activity dynamics with winner-take-all character modulated by an oscillatory rhythm. These neural mechanisms lay down the basis for cooperation and competition between the distributed units and their synaptic connections. Choosing human face recognition as a test task, we show that, under the condition of open-ended, unsupervised incremental learning, the system is able to form memory traces for individual faces in a parts-based fashion. On a lower memory layer the synaptic structure is developed to represent local facial features and their interrelations, while the identities of different persons are captured explicitly on a higher layer. An additional property of the resulting representations is the sparseness of both the activity during the recall and the synaptic patterns comprising the memory traces. PMID:19862345

The List-Strength Effect in Recall: Relative-Strength Competition and Retrieval Inhibition May both Contribute to Forgetting

ERIC Educational Resources Information Center

Verde, Michael F.

2009-01-01

According to the principle of relative-strength competition, stronger items in memory block the retrieval of weaker items. This principle, integral to many theories of forgetting over the years, derives much of its support from the list-strength effect (LSE), in which strengthening some items in a study list makes it more difficult to recall other…

Human Cognition and Information Display in C3I System Tasks.

DTIC Science & Technology

1988-12-01

goes without saying that rule-based tasks are the easiest to automate, but for reasons discussed earlier, they still merit our attention . Moreover...selective attention task. Since selective attention must operate after memory retrieval, it is only when different responses are elicited that the...stimuli that is processed by impairing the memory traces of signals that originally attract less attention . Although the research reviewed above gives

The dynamic nature of the reconsolidation process and its boundary conditions: Evidence based on human tests.

PubMed

Fernández, Rodrigo S; Bavassi, Luz; Forcato, Cecilia; Pedreira, María E

2016-04-01

The reconsolidation process is the mechanism by which the strength and/or content of consolidated memories are updated. This process is triggered by the presentation of a reminder (training cues). It is not always possible to trigger the reconsolidation process. For example, memory age and strength are boundary conditions for the reconsolidation process. Here, we investigated the dynamic changes in these conditions. We propose that the boundary conditions of the reconsolidation process are not fixed and vary as a consequence of the interaction between memory features and reminder characteristics. To modify memory properties, participants received a threatening social protocol that improves memory acquisition or a control condition (fake, without social interaction) prior to learning pairs of meaningless syllables. To determine whether a strong young or old declarative memory undergoes the reconsolidation process, we used an interference task (a second list of pairs of meaningless syllables) to disrupt memory re-stabilization. To assess whether the older memory could be strengthened, we repeated the triggering of reconsolidation. Strong young or old memories modulated by a threatening experience could be interfered during reconsolidation and updated (strengthened) by reconsolidation. Rather than being fixed, boundary conditions vary according to the memory features (strong memory), which indicates the dynamic nature of the reconsolidation process. Our findings demonstrate that it is possible to modify these limits by recruiting the reconsolidation process and making it functionally operative again. This novel scenario opens the possibility to new therapeutically approaches that take into account the reconsolidation process. Copyright © 2016 Elsevier Inc. All rights reserved.

Measuring Cognitive and Metacognitive Regulatory Processes during Hypermedia Learning: Issues and Challenges

ERIC Educational Resources Information Center

Azevedo, Roger; Moos, Daniel C.; Johnson, Amy M.; Chauncey, Amber D.

2010-01-01

Self-regulated learning (SRL) with hypermedia environments involves a complex cycle of temporally unfolding cognitive and metacognitive processes that impact students' learning. We present several methodological issues related to treating SRL as an event and strengths and challenges of using online trace methodologies to detect, trace, model, and…

Memory profiles of Down, Williams, and fragile X syndromes: implications for reading development.

PubMed

Conners, Frances A; Moore, Marie S; Loveall, Susan J; Merrill, Edward C

2011-06-01

The purpose of this review was to understand the types of memory impairments that are associated with intellectual disability (ID, formerly called mental retardation) and the implications of these impairments for reading development. Specifically, studies on working memory, delayed memory and learning, and semantic/conceptual memory in Down syndrome, Williams syndrome, and fragile X syndrome were examined. A distinct memory profile emerged for each of the 3 etiologies of ID. Memory profiles are discussed in relation to strengths and weaknesses in reading skills in these three etiologies. We suggest that reading instruction be designed to capitalize on relatively stronger memory skills while providing extra support for especially challenging aspects of reading.

Memory. Engram cells retain memory under retrograde amnesia.

PubMed

Ryan, Tomás J; Roy, Dheeraj S; Pignatelli, Michele; Arons, Autumn; Tonegawa, Susumu

2015-05-29

Memory consolidation is the process by which a newly formed and unstable memory transforms into a stable long-term memory. It is unknown whether the process of memory consolidation occurs exclusively through the stabilization of memory engrams. By using learning-dependent cell labeling, we identified an increase of synaptic strength and dendritic spine density specifically in consolidated memory engram cells. Although these properties are lacking in engram cells under protein synthesis inhibitor-induced amnesia, direct optogenetic activation of these cells results in memory retrieval, and this correlates with retained engram cell-specific connectivity. We propose that a specific pattern of connectivity of engram cells may be crucial for memory information storage and that strengthened synapses in these cells critically contribute to the memory retrieval process. Copyright © 2015, American Association for the Advancement of Science.

Results of the U.S. Geological Survey's Analytical Evaluation Program for standard reference samples: T-155 (trace constituents), M-148 (major constituents), N-59 (nutrient constituents), N-60 (nutrient constituents), P-31 (low ionic strength constituents), GWT-4 (ground-water trace constituents) and Hg-27 (Mercury) distributed in September 1998

USGS Publications Warehouse

Farrar, Jerry W.

1999-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for seven standard reference samples -- T-155 (trace constituents), M-148 (major constituents), N-59 (nutrient constituents), N-60 (nutrient constituents), P-31 (low ionic strength constituents), GWT-4 (ground-water trace constituents), and Hg- 27 (mercury) -- which were distributed in September 1998 to 162 laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 136 of the laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the seven reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the seven standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Report on the U.S. Geological Survey's evaluation program for standard reference samples distributed in October 1994 : T-131 (trace constituents), T-133 (trace constituents), M-132 (major constituents), N-43 (nutrients), N-44 (nutrients), P-23 (low ionic strength) and Hg-19 (mercury)

USGS Publications Warehouse

Long, H. Keith; Farrar, Jerry W.

1995-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for 7 standard reference samples--T-131 (trace constituents), T-133 (trace constituents), M-132 (major constituents), N-43 (nutrients), N-44 (nutrients), P-23 (low ionic strength), and Hg-19 (mercury). The samples were distributed in October 1994 to 131 laboratories registered in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 121 of the laboratories were evaluated with respect to: overall laboratory performance and relative laboratory performance for each analyte in the seven reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the seven standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Bipartite non-classical correlations for a lossy two connected qubit-cavity systems: trace distance discord and Bell's non-locality

NASA Astrophysics Data System (ADS)

Mohamed, Abdel-Baset A.

2018-04-01

In this paper, some non-classical correlations are investigated for bipartite partitions of two qubits trapped in two spatially separated cavities connected by an optical fiber. The results show that the trace distance discord and Bell's non-locality introduce other quantum correlations beyond the entanglement. Moreover, the correlation functions of the trace distance discord and the Bell's non-locality are very sensitive to the initial correlations, the coupling strengths, and the dissipation rates of the cavities. The fluctuations of the correlation functions between their initial values and gained (loss) values appear due to the unitary evolution of the system. These fluctuations depend on the chosen initial correlations between the two subsystems. The maximal violations of Bell's inequality occur when the logarithmic negativity and the trace distance discord reach certain values. It is shown that the robustness of the non-classical correlations, against the dissipation rates of the cavities, depends on the bipartite partitions reduced density matrices of the system, and is also greatly enhanced by choosing appropriate coupling strengths.

A Single-System Model Predicts Recognition Memory and Repetition Priming in Amnesia

PubMed Central

Kessels, Roy P.C.; Wester, Arie J.; Shanks, David R.

2014-01-01

We challenge the claim that there are distinct neural systems for explicit and implicit memory by demonstrating that a formal single-system model predicts the pattern of recognition memory (explicit) and repetition priming (implicit) in amnesia. In the current investigation, human participants with amnesia categorized pictures of objects at study and then, at test, identified fragmented versions of studied (old) and nonstudied (new) objects (providing a measure of priming), and made a recognition memory judgment (old vs new) for each object. Numerous results in the amnesic patients were predicted in advance by the single-system model, as follows: (1) deficits in recognition memory and priming were evident relative to a control group; (2) items judged as old were identified at greater levels of fragmentation than items judged new, regardless of whether the items were actually old or new; and (3) the magnitude of the priming effect (the identification advantage for old vs new items) overall was greater than that of items judged new. Model evidence measures also favored the single-system model over two formal multiple-systems models. The findings support the single-system model, which explains the pattern of recognition and priming in amnesia primarily as a reduction in the strength of a single dimension of memory strength, rather than a selective explicit memory system deficit. PMID:25122896

BDNF is essential to promote persistence of long-term memory storage

PubMed Central

Bekinschtein, Pedro; Cammarota, Martín; Katche, Cynthia; Slipczuk, Leandro; Rossato, Janine I.; Goldin, Andrea; Izquierdo, Ivan; Medina, Jorge H.

2008-01-01

Persistence is a characteristic attribute of long-term memories (LTMs). However, little is known about the molecular mechanisms that mediate this process. We recently showed that persistence of LTM requires a late protein synthesis- and BDNF-dependent phase in the hippocampus. Here, we show that intrahippocampal delivery of BDNF reverses the deficit in memory persistence caused by inhibition of hippocampal protein synthesis. Importantly, we demonstrate that BDNF induces memory persistence by itself, transforming a nonlasting LTM trace into a persistent one in an ERK-dependent manner. Thus, BDNF is not only necessary, but sufficient to induce a late postacquisition phase in the hippocampus essential for persistence of LTM storage. PMID:18263738

Unequal-Strength Source zROC Slopes Reflect Criteria Placement and Not (Necessarily) Memory Processes

ERIC Educational Resources Information Center

Starns, Jeffrey J.; Pazzaglia, Angela M.; Rotello, Caren M.; Hautus, Michael J.; Macmillan, Neil A.

2013-01-01

Source memory zROC slopes change from below 1 to above 1 depending on which source gets the strongest learning. This effect has been attributed to memory processes, either in terms of a threshold source recollection process or changes in the variability of continuous source evidence. We propose 2 decision mechanisms that can produce the slope…

Beyond Capacity Limitations: Determinants of Word Recall Performance on Verbal Working Memory Span Tasks in Children with SLI

ERIC Educational Resources Information Center

Mainela-Arnold, Elina; Evans, Julia L.

2005-01-01

Reduced verbal working memory capacity has been proposed as a possible account of language impairments in specific language impairment (SLI). Studies have shown, however, that differences in strength of linguistic representations in the form of word frequency affect list recall and performance on verbal working memory tasks. This suggests that…

The Dynamics of Scaling: A Memory-Based Anchor Model of Category Rating and Absolute Identification

ERIC Educational Resources Information Center

Petrov, Alexander A.; Anderson, John R.

2005-01-01

A memory-based scaling model--ANCHOR--is proposed and tested. The perceived magnitude of the target stimulus is compared with a set of anchors in memory. Anchor selection is probabilistic and sensitive to similarity, base-level strength, and recency. The winning anchor provides a reference point near the target and thereby converts the global…

Fuzzy-Trace Theory and Lifespan Cognitive Development

PubMed Central

Brainerd, C J.; Reyna, Valerie F.

2015-01-01

Fuzzy-trace theory (FTT) emphasizes the use of core theoretical principles, such as the verbatim-gist distinction, to predict new findings about cognitive development that are counterintuitive from the perspective of other theories or of common-sense. To the extent that such predictions are confirmed, the range of phenomena that are explained expands without increasing the complexity of the theory's assumptions. We examine research on recent examples of such predictions during four epochs of cognitive development: childhood, adolescence, young adulthood, and late adulthood. During the first two, the featured predictions are surprising developmental reversals in false memory (childhood) and in risky decision making (adolescence). During young adulthood, FTT predicts that a retrieval operation that figures centrally in dual-process theories of memory, recollection, is bivariate rather than univariate. During the late adulthood, FTT identifies a retrieval operation, reconstruction, that has been omitted from current theories of normal memory declines in aging and pathological declines in dementia. The theory predicts that reconstruction is a major factor in such declines and that it is able to forecast future dementia. PMID:26644632

Genotype-dependent characteristics of behavior in mice in cognitive tests. The effects of Noopept.

PubMed

Bel'nik, A P; Ostrovskaya, R U; Poletaeva, I I

2009-01-01

Male C57BL/6J, BALB/c, and DBA/2J mice showed differences in their abilities to perform two cognitive tests. C57BL/6J mice had good learning ability and memory trace retention (at 10 days) in a simplified Morris maze, while BALB/c mice had low levels of memory trace retention and DBA/2J mice had low learning ability in this test. I.p. administration of the nootropic agent Noopept (GVS-111, N-phenylacetyl-L-prolylglycine ethyl ester) at a dose of 0.5 mg/kg 15 min before the start of the test induced significant improvements in long-term memory in this test in BALB/c mice but no further improvement in C57BL/6J mice, and had no effect in DBA/2J mice. On testing the ability to extrapolate the direction of movement of a stimulus, administration of Noopept increased the proportion of correct responses in C57BL/6J and BALB/c mice, but had no effect in DBA/2J mice.

[Genotype-dependent mice behavior in cognitive tasks. Effect of noopept].

PubMed

Bel'nik, A P; Ostrovskaia, R U; Poletaeva, I I

2007-01-01

The interstrain differences in performance of C57BL/6J, BALB/c and DBA/2J male mice in two cognitive tasks were found. Mice C57BL/6J showed good learning ability and preservation of memory traces tested 10 days after performance in a simplified version of Morris water maze. Mice BALB/c learned the task but, virtually, no long-term memory traces were revealed, whereas DBA/2J demonstrated poor learning. The effect of nootropic drug Noopept (GVS-111, N-phenil-acetyl-L-prolylglycin ethyl ether) was shown to be genotype-dependent. Its administration (0.5 mg/kg i.p., 15 min before learning) improved the long-term memory in Morris test in BALB/c mice but failed to produce any improvement in C57BL/6J. The ability of mice for extrapolation of the direction of stimulus movement differently changed after Noopept injections: the proportion of correct task solutions increased in C57BL/6J and BALB/c mice, whereas the performance of DBA/2J did not change.

Decoding attended information in short-term memory: an EEG study.

PubMed

LaRocque, Joshua J; Lewis-Peacock, Jarrod A; Drysdale, Andrew T; Oberauer, Klaus; Postle, Bradley R

2013-01-01

For decades it has been assumed that sustained, elevated neural activity--the so-called active trace--is the neural correlate of the short-term retention of information. However, a recent fMRI study has suggested that this activity may be more related to attention than to retention. Specifically, a multivariate pattern analysis failed to find evidence that information that was outside the focus of attention, but nonetheless in STM, was retained in an active state. Here, we replicate and extend this finding by querying the neural signatures of attended versus unattended information within STM with electroencephalograpy (EEG), a method sensitive to oscillatory neural activity to which the previous fMRI study was insensitive. We demonstrate that in the delay-period EEG activity, there is information only about memory items that are also in the focus of attention. Information about items outside the focus of attention is not detectable. This result converges with the fMRI findings to suggest that, contrary to conventional wisdom, an active memory trace may be unnecessary for the short-term retention of information.

Fuzzy-Trace Theory and Lifespan Cognitive Development.

PubMed

Brainerd, C J; Reyna, Valerie F

2015-12-01

Fuzzy-trace theory (FTT) emphasizes the use of core theoretical principles, such as the verbatim-gist distinction, to predict new findings about cognitive development that are counterintuitive from the perspective of other theories or of common-sense. To the extent that such predictions are confirmed, the range of phenomena that are explained expands without increasing the complexity of the theory's assumptions. We examine research on recent examples of such predictions during four epochs of cognitive development: childhood, adolescence, young adulthood, and late adulthood. During the first two, the featured predictions are surprising developmental reversals in false memory (childhood) and in risky decision making (adolescence). During young adulthood, FTT predicts that a retrieval operation that figures centrally in dual-process theories of memory, recollection, is bivariate rather than univariate. During the late adulthood, FTT identifies a retrieval operation, reconstruction, that has been omitted from current theories of normal memory declines in aging and pathological declines in dementia. The theory predicts that reconstruction is a major factor in such declines and that it is able to forecast future dementia.

Robust Vacuum-/Air-Dried Graphene Aerogels and Fast Recoverable Shape-Memory Hybrid Foams.

PubMed

Li, Chenwei; Qiu, Ling; Zhang, Baoqing; Li, Dan; Liu, Chen-Yang

2016-02-17

New graphene aerogels can be fabricated by vacuum/air drying, and because of the mechanical robustness of the graphene aerogels, shape-memory polymer/graphene hybrid foams can be fabricated by a simple infiltration-air-drying-crosslinking method. Due to the superelasticity, high strength, and good electrical conductivity of the as-prepared graphene aerogels, the shape-memory hybrid foams exhibit excellent thermotropical and electrical shape-memory properties, outperforming previously reported shape-memory polymer foams. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Medial prefrontal cortex dopamine controls the persistent storage of aversive memories

PubMed Central

Gonzalez, María C.; Kramar, Cecilia P.; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín; Medina, Jorge H.

2014-01-01

Medial prefrontal cortex (mPFC) is essential for initial memory processing and expression but its involvement in persistent memory storage has seldom been studied. Using the hippocampus dependent inhibitory avoidance learning task and the hippocampus-independent conditioned taste aversion paradigm together with specific dopamine receptor agonists and antagonists we found that persistence but not formation of long-term aversive memories requires dopamine D1/D5 receptors activation in mPFC immediately after training and, depending on the task, between 6 and 12 h later. Our results indicate that besides its well-known participation in retrieval and early consolidation, mPFC also modulates the endurance of long-lasting aversive memories regardless of whether formation of the aversive mnemonic trace requires the participation of the hippocampus. PMID:25506318

Correcting false information in memory: manipulating the strength of misinformation encoding and its retraction.

PubMed

Ecker, Ullrich K H; Lewandowsky, Stephan; Swire, Briony; Chang, Darren

2011-06-01

Information that is presumed to be true at encoding but later on turns out to be false (i.e., misinformation) often continues to influence memory and reasoning. In the present study, we investigated how the strength of encoding and the strength of a later retraction of the misinformation affect this continued influence effect. Participants read an event report containing misinformation and a subsequent correction. Encoding strength of the misinformation and correction were orthogonally manipulated either via repetition (Experiment 1) or by imposing a cognitive load during reading (Experiment 2). Results suggest that stronger retractions are effective in reducing the continued influence effects associated with strong misinformation encoding, but that even strong retractions fail to eliminate continued influence effects associated with relatively weak encoding. We present a simple computational model based on random sampling that captures this effect pattern, and conclude that the continued influence effect seems to defy most attempts to eliminate it.

Strength-based criterion shifts in recognition memory.

PubMed

Singer, Murray

2009-10-01

In manipulations of stimulus strength between lists, a more lenient signal detection criterion is more frequently applied to a weak than to a strong stimulus class. However, with randomly intermixed weak and strong test probes, such a criterion shift often does not result. A procedure that has yielded delay-based within-list criterion shifts was applied to strength manipulations in recognition memory for categorized word lists. When participants made semantic ratings about each stimulus word, strength-based criterion shifts emerged regardless of whether words from pairs of categories were studied in separate blocks (Experiment 1) or in intermixed blocks (Experiment 2). In Experiment 3, the criterion shift persisted under the semantic-rating study task, but not under rote memorization. These findings suggest that continually adjusting the recognition decision criterion is cognitively feasible. They provide a technique for manipulating the criterion shift, and they identify competing theoretical accounts of these effects.

Memory consolidation in humans: new evidence and opportunities

PubMed Central

Maguire, Eleanor A

2014-01-01

We are endlessly fascinated by memory; we desire to improve it and fear its loss. While it has long been recognized that brain regions such as the hippocampus are vital for supporting memories of our past experiences (autobiographical memories), we still lack fundamental knowledge about the mechanisms involved. This is because the study of specific neural signatures of autobiographical memories in vivo in humans presents a significant challenge. However, recent developments in high-resolution structural and functional magnetic resonance imaging coupled with advanced analytical methods now permit access to the neural substrates of memory representations that has hitherto been precluded in humans. Here, I describe how the application of ‘decoding’ techniques to brain-imaging data is beginning to disclose how individual autobiographical memory representations evolve over time, deepening our understanding of systems-level consolidation. In particular, this prompts new questions about the roles of the hippocampus and ventromedial prefrontal cortex and offers new opportunities to interrogate the elusive memory trace that has for so long confounded neuroscientists. PMID:24414174

Look before you leap: sensory memory improves decision making.

PubMed

Vlassova, Alexandra; Pearson, Joel

2013-09-01

Simple decisions require the processing and evaluation of perceptual and cognitive information, the formation of a decision, and often the execution of a motor response. This process involves the accumulation of evidence over time until a particular choice reaches a decision threshold. Using a random-dot-motion stimulus, we showed that simply delaying responses after the stimulus offset can almost double accuracy, even in the absence of new incoming visual information. However, under conditions in which the otherwise blank interval was filled with a sensory mask or concurrent working memory load was high, performance gains were lost. Further, memory and perception showed equivalent rates of evidence accumulation, suggesting a high-capacity memory store. We propose an account of continued evidence accumulation by sequential sampling from a simultaneously decaying memory trace. Memories typically decay with time, hence immediate inquiry trumps later recall from memory. However, the results we report here show the inverse: Inspecting a memory trumps viewing the actual object.

NR2A- and NR2B-Containing NMDA Receptors in the Prelimbic Medial Prefrontal Cortex Differentially Mediate Trace, Delay, and Contextual Fear Conditioning

ERIC Educational Resources Information Center

Gilmartin, Marieke R.; Kwapis, Janine L.; Helmstetter, Fred J.

2013-01-01

Activation of "N"-methyl-D-aspartate receptors (NMDAR) in the prelimbic medial prefrontal cortex (PL mPFC) is necessary for the acquisition of both trace and contextual fear memories, but it is not known how specific NR2 subunits support each association. The NR2B subunit confers unique properties to the NMDAR and may differentially…

Data Triage

DTIC Science & Technology

2007-06-01

particle accelerators cannot run unless enough network band- width is available to absorb their data streams. DOE scientists running simulations routinely...send tuples to TelegraphCQ. To simulate a less-powerful machine, I increased the playback rate of the trace by a factor of 10 and reduced the query...III CPUs and 1.5 GB of main memory. To simulate using a less powerful embedded CPU, I wrote a program that would “play back” the trace at a multiple

Neural principles of memory and a neural theory of analogical insight

NASA Astrophysics Data System (ADS)

Lawson, David I.; Lawson, Anton E.

1993-12-01

Grossberg's principles of neural modeling are reviewed and extended to provide a neural level theory to explain how analogies greatly increase the rate of learning and can, in fact, make learning and retention possible. In terms of memory, the key point is that the mind is able to recognize and recall when it is able to match sensory input from new objects, events, or situations with past memory records of similar objects, events, or situations. When a match occurs, an adaptive resonance is set up in which the synaptic strengths of neurons are increased; thus a long term record of the new input is formed in memory. Systems of neurons called outstars and instars are presumably the underlying units that enable this to occur. Analogies can greatly facilitate learning and retention because they activate the outstars (i.e., the cells that are sampling the to-be-learned pattern) and cause the neural activity to grow exponentially by forming feedback loops. This increased activity insures the boost in synaptic strengths of neurons, thus causing storage and retention in long-term memory (i.e., learning).

High Working Memory Capacity Predicts Less Retrieval Induced Forgetting

PubMed Central

Mall, Jonathan T.; Morey, Candice C.

2013-01-01

Background Working Memory Capacity (WMC) is thought to be related to executive control and focused memory search abilities. These two hypotheses make contrasting predictions regarding the effects of retrieval on forgetting. Executive control during memory retrieval is believed to lead to retrieval induced forgetting (RIFO) because inhibition of competing memory traces during retrieval renders them temporarily less accessible. According to this suggestion, superior executive control should increase RIFO. Alternatively, superior focused search abilities could diminish RIFO, because delimiting the search set reduces the amount of competition between traces and thus the need for inhibition. Some evidence suggests that high WMC is related to more RIFO, which is inconsistent with the focused search hypothesis. Methodology/Principal Findings Using the RIFO paradigm, we created distinct and overlapping categories to manipulate the amount of competition between them. This overlap increased competition between some categories while exclusive use of weak exemplars ensured negligible effects of output interference and integration. Low WMC individuals exhibited RIFO within and between overlapping categories, indicating the effect of resolving competition during retrieval. High WMC individuals only exhibited between-category RIFO, suggesting they experienced reduced competition resolution demands. Low WMC Individuals exhibited the strongest RIFO and no retrieval benefits when interference resolution demands were high. Conclusions/Significance Our findings qualify the inhibitory explanation for RIFO by incorporating the focused search hypothesis for materials that are likely to pose extraordinary challenges at retrieval. The results highlight the importance of considering individual differences in retrieval-induced effects and qualify existing models of these effects. PMID:23326359

High working memory capacity predicts less retrieval induced forgetting.

PubMed

Mall, Jonathan T; Morey, Candice C

2013-01-01

Working Memory Capacity (WMC) is thought to be related to executive control and focused memory search abilities. These two hypotheses make contrasting predictions regarding the effects of retrieval on forgetting. Executive control during memory retrieval is believed to lead to retrieval induced forgetting (RIFO) because inhibition of competing memory traces during retrieval renders them temporarily less accessible. According to this suggestion, superior executive control should increase RIFO. Alternatively, superior focused search abilities could diminish RIFO, because delimiting the search set reduces the amount of competition between traces and thus the need for inhibition. Some evidence suggests that high WMC is related to more RIFO, which is inconsistent with the focused search hypothesis. Using the RIFO paradigm, we created distinct and overlapping categories to manipulate the amount of competition between them. This overlap increased competition between some categories while exclusive use of weak exemplars ensured negligible effects of output interference and integration. Low WMC individuals exhibited RIFO within and between overlapping categories, indicating the effect of resolving competition during retrieval. High WMC individuals only exhibited between-category RIFO, suggesting they experienced reduced competition resolution demands. Low WMC Individuals exhibited the strongest RIFO and no retrieval benefits when interference resolution demands were high. Our findings qualify the inhibitory explanation for RIFO by incorporating the focused search hypothesis for materials that are likely to pose extraordinary challenges at retrieval. The results highlight the importance of considering individual differences in retrieval-induced effects and qualify existing models of these effects.

Impairment of learning and memory after photothrombosis of the prefrontal cortex in rat brain: effects of Noopept.

PubMed

Romanova, G A; Shakova, F M; Gudasheva, T A; Ostrovskaya, R U

2002-12-01

Experiments were performed on rats trained conditioned passive avoidance response. Acquisition and retention of memory traces were impaired after photothrombosis of the prefrontal cortex. The acyl-prolyl-containing dipeptide Noopept facilitated retention and retrieval of a conditioned passive avoidance response, normalized learning capacity in animals with ischemic damage to the cerebral cortex, and promoted finish training in rats with hereditary learning deficit. These results show that Noopept improves all three stages of memory. It should be emphasized that the effect of Noopept was most pronounced in animals with impaired mnesic function.

Engram Cells Retain Memory Under Retrograde Amnesia

PubMed Central

Ryan, Tomás J.; Roy, Dheeraj S.; Pignatelli, Michele; Arons, Autumn; Tonegawa, Susumu

2017-01-01

Memory consolidation is the process by which a newly formed and unstable memory transforms into a stable long-term memory. It is unknown whether the process of memory consolidation occurs exclusively by the stabilization of memory engrams. By employing learning-dependent cell labeling, we identified an increase of synaptic strength and dendritic spine density specifically in consolidated memory engram cells. While these properties are lacking in the engram cells under protein synthesis inhibitor-induced amnesia, direct optogenetic activation of these cells results in memory retrieval, and this correlates with the retained engram cell-specific connectivity. We propose that a specific pattern of connectivity of engram cells may be crucial for memory information storage and that strengthened synapses in these cells critically contribute to the memory retrieval process. PMID:26023136

Modifying Memory for a Museum Tour in Older Adults: Reactivation-Related Updating that Enhances and Distorts Memory is Reduced in Aging

PubMed Central

St Jacques, Peggy L.; Montgomery, Daniel; Schacter, Daniel L.

2015-01-01

Memory reactivation, the activation of a latent memory trace when we are reminded of a past experience, strengthens memory but can also contribute to distortions if new information present during reactivation is integrated with existing memory. In a previous study in young adults we found that the quality of memory reactivation, manipulated using the principle of encoding specificity and indexed by recollection ratings, modulated subsequent true and false memories for events experienced during a museum tour. Here, we examined age-related changes in the quality of memory reactivation on subsequent memory. Young and older adults reactivated memories for museum stops immediately followed by the presentation of a novel lure photo from an alternate tour version (i.e., reactivation plus new information). There was an increase in subsequent true memories for reactivated targets and for subsequent false memories for lures that followed reactivated targets, when compared to baseline target and lure photos. However, the influence of reactivation on subsequent memories was reduced in older adults. These data reveal that aging alters reactivation-related updating processes that allow memories to be strengthened and updated with new information-consequently reducing memory distortions in older compared to young adults. PMID:24993055

Manipulations of attention dissociate fragile visual short-term memory from visual working memory.

PubMed

Vandenbroucke, Annelinde R E; Sligte, Ilja G; Lamme, Victor A F

2011-05-01

People often rely on information that is no longer in view, but maintained in visual short-term memory (VSTM). Traditionally, VSTM is thought to operate on either a short time-scale with high capacity - iconic memory - or a long time scale with small capacity - visual working memory. Recent research suggests that in addition, an intermediate stage of memory in between iconic memory and visual working memory exists. This intermediate stage has a large capacity and a lifetime of several seconds, but is easily overwritten by new stimulation. We therefore termed it fragile VSTM. In previous studies, fragile VSTM has been dissociated from iconic memory by the characteristics of the memory trace. In the present study, we dissociated fragile VSTM from visual working memory by showing a differentiation in their dependency on attention. A decrease in attention during presentation of the stimulus array greatly reduced the capacity of visual working memory, while this had only a small effect on the capacity of fragile VSTM. We conclude that fragile VSTM is a separate memory store from visual working memory. Thus, a tripartite division of VSTM appears to be in place, comprising iconic memory, fragile VSTM and visual working memory. Copyright © 2011 Elsevier Ltd. All rights reserved.

Modifying memory for a museum tour in older adults: Reactivation-related updating that enhances and distorts memory is reduced in ageing.

PubMed

St Jacques, Peggy L; Montgomery, Daniel; Schacter, Daniel L

2015-01-01

Memory reactivation, the activation of a latent memory trace when we are reminded of a past experience, strengthens memory but can also contribute to distortions if new information present during reactivation is integrated with existing memory. In a previous study in young adults we found that the quality of memory reactivation, manipulated using the principle of encoding specificity and indexed by recollection ratings, modulated subsequent true and false memories for events experienced during a museum tour. Here in this study, we examined age-related changes in the quality of memory reactivation on subsequent memory. Memories of museum stops in young and older adults were reactivated and then immediately followed by the presentation of a novel lure photo from an alternate tour version (i.e., reactivation plus new information). There was an increase in subsequent true memories for reactivated targets and for subsequent false memories for lures that followed reactivated targets, when compared to baseline target and lure photos. However, the influence of reactivation on subsequent memories was reduced in older adults. These data reveal that ageing alters reactivation-related updating processes that allow memories to be strengthened and updated with new information, consequently reducing memory distortions in older adults compared to young adults.