Actual Memory Research Articles

Very long-term outcome in resected and non-resected patients with temporal lobe epilepsy with medial temporal lobe sclerosis: A multiple case-study

PurposeTo investigate the very long-term (i.e., ≥15 years) seizure, cognitive and psycho-social outcomes in resected patients (RP) with TLE compared to control patients not having undergone epilepsy surgery. MethodsWe applied a multiple case-study design including three non-resected patients (NRP) who were compared to a group of six RP. The latter were matched to the NRP according to clinical-demographic data. Outcome measures were various seizure, cognitive, and psycho-social variables. ResultsPatients were 56–72 years old. Seizure and AED outcome was more favourable among RP. RP reported better self-perceived overall health but higher subjective memory complaints. Upon formal neuropsychological testing, RP presented with lower verbal memory scores. Very long-term memory decline was evident in left-sided RP with good baseline memory scores, while RP with lower baseline performance, right-sided RP and NRP remained stable. Seizure-freedom had remarkable effects on the relationship between objective and subjective outcome: seizure-free patients, in general, subjectively reported the best psychosocial and cognitive outcome – irrespective of neuropsychological test results. ConclusionOur study suggests positive effects of TLE surgery in the very long-term course of ≥15 years postoperatively. Long-term seizure-freedom appears to have the strongest impact on patients’ subjectively perceived psycho-social and cognitive outcome and may even outweigh actual memory disturbances and/or decline. Overall, our data do not support the assumption of a generally accelerated cognitive decline in patients with TLE.

Actual memory as a mediator of the amyloid-subjective cognitive decline relationship

IntroductionAmyloid pathology in cognitively normal adults is associated with subjective cognitive decline, potentially reflecting awareness of Alzheimer's-related memory deficits. To clarify the mechanism underlying this relationship, we used mediational analyses to determine the role of depression, anxiety, and actual memory performance.MethodsTo assess amyloid deposition, we imaged 85 cognitively normal adults with florbetapir positron emission tomography imaging. Subjective cognitive decline was measured using a multidimensional instrument that assessed seven subjective memory domains. Mediational measures included assessments of actual memory performance (current and retrospective longitudinal change), depression, and anxiety.ResultsThe relationship between amyloid and subjective cognitive decline was mediated by poorer memory performance and greater retrospective memory decline, not depression or anxiety. The mediational roles were significant for domains associated with memory function and memory-related anxiety.DiscussionIn individuals harboring amyloid, self-reported beliefs of declining memory likely indicate early self-awareness of actual worsening function rather than depression or anxiety.

A Probabilistic Range Query of Moving Objects in Road Network

The range query of moving objects in a road network is widely used in battlefield environment, intelligent transportation systems, and mobile phone location. It has gradually become a research hotspot in the field of spatiotemporal data management. Most of the existing research on range query of moving objects in the road network is based on the premise of dense sampling of the device and complete storage of data. It ignores the uncertainty of discrete location data caused by a blind area of actual devices and limited memory, which cannot guarantee the accuracy of the range query. In this paper, the processing framework of probabilistic range query of moving objects in the road network is constructed. A spatiotemporal index structure is proposed based on the framework. This index can effectively represent time weights and the relationship between road sections. The probabilistic range query algorithm of moving objects in the road network with an uncertain trajectory caused by sampling frequency is designed and implemented. The experiments verify that the method proposed in this paper can improve query efficiency and ensure query accuracy.

Metamemory and memory for a wide range of font sizes: What is the contribution of perceptual fluency?

Words printed in a larger 48-point font are judged to be more memorable than words printed in a smaller 18-point font, although font size does not affect actual memory. To clarify the basis of this font size effect on metamemory and memory, 4 experiments investigated how presenting words in 48 (Experiment 1) or 4 (Experiments 2 to 4) font sizes between 6 point and 500 point affected judgments of learning (JOLs) and recall performance. Response times in lexical decision tasks were used to measure perceptual fluency. In all experiments, perceptual fluency was lower for words presented in very small and very large font sizes than for words presented in intermediate font sizes. In contrast, JOLs increased monotonically with font size, even beyond the point where a large font impaired perceptual fluency. Assessments of people's metacognitive beliefs about font size revealed that the monotonic increase in JOLs was not due to beliefs masking perceptual fluency effects (Experiment 3). Also, JOLs still increased across the whole range of font sizes when perceptual fluency was made salient at study (Experiment 4). In all experiments but Experiment 4, recall performance increased with increasing font size, although to a lesser extent than JOLs. Overall, the current study supports the idea that metacognitive beliefs underlie font size effects in metamemory. As important, it reveals that people's font size beliefs have some accuracy. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Exploring the intrinsic-extrinsic distinction in prospective metamemory

Abstract The overwhelming majority of research on metamemory examines retrospective memory – memory for past events. The metamemory of prospective memory – remembering to carry out intentions in the future – is little studied. The cue utilization account is a prominent framework for analyzing retrospective metamemory, here applied to prospective metamemory. This framework predicts that intrinsic cues (e.g., characteristics of the to-be-remembered information) readily impact metamemory whereas extrinsic cues (e.g., features of the general learning environment) have much less impact. The current study examined prospective memory using target-response word pairs. Participants were to remember to interrupt an ongoing task when a target was noticed, and then recall the associated response. Prior to the ongoing task, participants predicted (using judgments-of-learning, JOLs) whether they would notice a given target and whether they would recall the response for that target. This paradigm allows an assessment of metamemory and actual memory for the prospective component (the noticing of the target) and the retrospective component (the retrieval of the response). Four experiments found that prospective-JOLs were affected by an intrinsic cue (target-word association) but not by an extrinsic cue (target focality), as predicted by the cue-utilization account. The same results were found for the retrospective-JOLs. The results provide initial evidence that the cue-utilization framework generalizes to prospective metamemory. These results also revealed two complementary metamemorial illusions: target-response association impacts prospective-JOLs but not actual prospective memory performance, and target focality fails to impact prospective-JOLs but does affect actual prospective memory. This indicates that prospective metamemory may be subject to illusions in ways similar to retrospective metamemory.

Historic Houses as Pillars of Memory: Cases from Cairo, Egypt

The relationship between collective memory and the built environment is a complex relationship. Though the concept of memory is fragile, the maintenance and continuation of urban memory are essential to maintain groups' identities and to support the sense of place and place attachment between community members and the architectural settings they use and/or reside in. Preserving the physical aspects of buildings, spaces and settings that are linked with memory, is important to preserve the memory, however, the mere preservation does not guarantee the continuation of memory. The maintenance and continuation of memory is a process that depends on several factors, where the preservation of the physical aspects is only one among several. This paper aims at a better understanding of the intricate relationship between collective memory and the built environment, focusing on the processes of formation, stimulation and consolidation of memory. The paper sheds the lights on historic houses that are embedded with significant meanings and memories to their social contexts. It claims that historic houses can easily shift from ‘potential cultural memory' to ‘actual cultural memory' that could act as pillars of memory to their surrounding community, if the conservation process is done comprehensively, that is to include not only the physical and spatial aspects of memory but also to tackle the social dimensions of memory as well. The paper is organized into three sections: the first investigates the memory formation process, focusing on the social and the spatial dimension of memory, then the second investigates the possible channels to memory stimulation and consolidation, and finally, as a case study, the third section investigates the memory of two historic houses in Cairo, Egypt. The review of the works undertaken in the two houses highlights the difference and the distance between the concept of restoration and the essence of conservation. Findings yielded that, urban memory is an important aspect of cultural heritage that should to be captured and preserved for current and future generations, an aspect that is missing in local conservation approaches. Moreover, to be maintained, urban memory needs physical, social and moral props.

Russia and Bulgaria: From «Memorial Wars» to the Search for Common Past

The reference to history in the context of Russia’s foreign policy is considered as an appeal to the quasi-transcendence, whereby an ideal dimension is added to the practical (political, economic) aspects of international relations. It is noted that only in the 2010s Russian diplomacy began to pay special attention to such «symbolic games», designed to provide the moral basis for foreign policy through reference to the historical role that Russia plays on the international arena. This, in turn, leads to the dominance of performative practices, rather than to the building of dialogue spaces. In practice, the politicization of historical memory is conducted in two ways: inclusion in foreign policy discourse and by various symbolic practices of addressing to the common past during official visits. The author suggests distinguishing actual memory places and symbolic gestures aimed at their actualization. Russian-Bulgarian relations are characterized by asymmetry in the spaces of shared memory, memory places are mainly localized in Bulgaria. We outline main practices of turning places of memory into the common spaces of memory, but interpretations of these symbolic gestures in Russia and Bulgaria are structured by different national historical narratives. The memory of the Russian-Turkish war of 1877-1878 and the liberation of Bulgaria during the WWII are assigned greater importance in Bulgaria than in Russia. This asymmetry leads to the fact that a significant work of the Bulgarian authorities, Bulgarian and Russian public organizations on the arrangement of places of memory and setting up new memorials is invisible in Russia, while Russian foreign policy discourse is dominated by the emphasis on negative aspects (for example, actions of individual vandals to destroy the monument of the Soviet Army in Sofia). This deprives the ongoing work in the field of symbolic support and at the same time forms a myth of «Bulgarian ingratitude». The most striking example is the scandal during the 140-year celebration of the liberation of Bulgaria in March 2018, which is based on a different understanding of how the achievements of the Imperial period should be interpreted today.

Learning by heart-the relationship between resting vagal tone and metacognitive judgments: a pilot study.

Metacognitive awareness and resting vagally mediated heart rate variability (HRV) as a physiological trait marker of cognitive inhibitory control capacities are both associated with better well-being and seem to share a common neural basis. Executive functioning which is considered a prerequisite for delivering prospective metacognitive judgments has been found to be correlated with HRV. This pilot study addresses the question, whether metacognitive awareness and resting vagally mediated HRV are positively associated. A sample of 20 healthy participants was analyzed that completed a typical Judgment of Learning task after an electrocardiogram had been recorded. The root-mean-squares of successive differences were used to calculate vagally mediated HRV. Metacognitive awareness was measured by comparing the judgments of learning with the actual memory performance, yielding a deviation score. HRV was found to be positively correlated with metacognitive awareness. Results suggest that metacognitive abilities might relate to physiological trait markers of cognitive inhibitory control capacities. Further experimental studies are needed to investigate causal relations.

Characterizing the performance benefit of hybrid memory system for HPC applications

Abstract Heterogenous memory systems that consist of multiple memory technologies are becoming common in high-performance computing environments. Modern processors and accelerators, such as the Intel Knights Landing (KNL) CPU and NVIDIA Volta GPU, feature small-size high-bandwidth memory near the compute cores and large-size normal-bandwidth memory that is connected off-chip. Theoretically, HBM can provide about four times higher bandwidth than conventional DRAM. However, many factors impact the actual performance improvement that an application can achieve on such system. In this paper, we focus on the Intel KNL system and identify the most important factors on the application performance, including the application memory access pattern, the problem size, the threading level and the actual memory configuration. We use a set of representative applications from both scientific and data-analytics domains. Our results show that applications with regular memory access benefit from MCDRAM, achieving up to three times performance when compared to the performance obtained using only DRAM. On the contrary, applications with irregular memory access pattern are latency-bound and may suffer from performance degradation when using only MCDRAM. Also, we provide memory-centric analysis of four applications, identify their major data objects, correlate their characteristics to the performance improvement on the testbed.

Feigning Amnesia Moderately Impairs Memory for a Mock Crime Video.

Previous studies showed that feigning amnesia for a crime impairs actual memory for the target event. Lack of rehearsal has been proposed as an explanation for this memory-undermining effect of feigning. The aim of the present study was to replicate and extend previous research adopting a mock crime video instead of a narrative story. We showed participants a video of a violent crime. Next, they were requested to imagine that they had committed this offense and to either feign amnesia or confess the crime. A third condition was included: Participants in the delayed test-only control condition did not receive any instruction. On subsequent recall tests, participants in all three conditions were instructed to report as much information as possible about the offense. On the free recall test, feigning amnesia impaired memory for the video clip, but participants who were asked to feign crime-related amnesia outperformed controls. However, no differences between simulators and confessors were found on both correct cued recollection or on distortion and commission rates. We also explored whether inner speech might modulate memory for the crime. Inner speech traits were not found to be related to the simulating amnesia effect. Theoretical and practical implications of our results are discussed.

Is subjective memory change in old age based on accurate monitoring of age-related memory change? Evidence from two longitudinal studies.

Subjective memory change (SMC) in adulthood involves the perception that one's memory has declined from earlier levels of function. SMC has been conjectured to be more accurate than concurrent subjective memory because people use themselves as a standard of comparison. We used data from two longitudinal studies to contrast the accurate-monitoring-of-change hypothesis-actual memory change predicts SMC-against a constructed-judgment hypothesis that rated SMC is a function of rescaling concurrent memory beliefs without accessing actual memory change. It states that actual memory change has no predictive validity for SMC independent of concurrent memory beliefs. Data from both the Berlin Aging Study and the Health and Retirement Study (HRS) showed that older adults' current memory complaints strongly predicted current SMC, and that there was little relationship of longitudinally measured memory change to SMC, controlling on memory complaints. In the HRS there were reliable latent-growth-curve slope correlations of over .20 for change in episodic memory with both slopes of change in SMC and in memory complaints, yet little relationship of SMC slopes to episodic memory slopes, controlling on memory-complaint slopes. The results falsify the accurate-monitoring-of-change hypothesis regarding the origins of SMC in older adults. (PsycINFO Database Record

Generating lies produces lower memory predictions and higher memory performance than telling the truth: Evidence for a metacognitive illusion.

Manipulations that induce disfluency during encoding generally produce lower memory predictions for the disfluent condition than for the fluent condition. Similar to other manipulations of disfluency, generating lies takes longer and requires more mental effort than does telling the truth; hence, a manipulation of lie generation might produce patterns similar to other types of fluency for memory predictions. The current study systematically investigates the effect of a lie-generation manipulation on both actual and predicted memory performance. In a series of experiments, participants told the truth or generated plausible lies to general knowledge questions and made item-by-item predictions about their subsequent memory performance during encoding, followed by a free recall test. Participants consistently predicted their memory performance to be higher for truth than for lies (Experiments 1 through 4), despite their typically superior actual memory performance for lies than for the truth (Experiments 1 through 3), producing double dissociations between memory and metamemory. Moreover, lying led to longer response latencies than did telling the truth, showing that generating lies is in fact objectively more disfluent. An additional experiment compared memory predictions for truth and lie trials via a scenario about the lie-generation manipulation used in the present study, which revealed superior memory predictions of truth than of lies, providing proof for a priori beliefs about the effects of lying on predicted memory (Experiment 5). The effects of the current lie-generation manipulation on metamemory are discussed in light of experience-based and theory-based processes on making judgments of learning. Theoretical and practical implications of this experimental paradigm are also considered. (PsycINFO Database Record

Dendritic-Inspired Processing Enables Bio-Plausible STDP in Compound Binary Synapses

Brain-inspired learning mechanisms, e.g. spike timing dependent plasticity (STDP), enable agile and fast on-the-fly adaptation capability in a spiking neural network. When incorporating emerging nanoscale resistive non-volatile memory (NVM) devices, with ultra-low power consumption and high-density integration capability, a spiking neural network hardware would result in several orders of magnitude reduction in energy consumption at a very small form factor and potentially herald autonomous learning machines. However, actual memory devices have shown to be intrinsically binary with stochastic switching, and thus impede the realization of ideal STDP with continuous analog values. In this work, a dendritic-inspired processing architecture is proposed in addition to novel CMOS neuron circuits. The utilization of spike attenuations and delays transforms the traditionally undesired stochastic behavior of binary NVMs into a useful leverage that enables biologically-plausible STDP learning. As a result, this work paves a pathway to adopt practical binary emerging NVM devices in brain-inspired neuromorphic computing.

Beliefs about Memory as a Mediator of Relations between Metacognitive Beliefs and Actual Memory Performance

ABSTRACTThe goal of the present study was to investigate relationships between personal beliefs about memory, metacognitive beliefs, and actual memory performance. One hundred thirty-seven participants' (aged 20 to 60 years) metacognitive beliefs were measured using the Metacognition Questionnaire (MCQ-30), memory beliefs were measured using the Personal Beliefs about Memory Instrument (PBMI), and an episodic memory task was used to measure actual memory performance, memory predictions, and postdictions. Younger adults had lower scores on the positive beliefs subfactor of the MCQ-30, higher scores on retrospective change and control subfactors of the PBMI, and outperformed middle-aged adults on recall and recall postdiction. Path analysis showed that individuals' beliefs about memory mediate the relationship between metacognitive beliefs and actual memory performance. Specifically, low lack of confidence (or less worry) in one's own memory and attentional capabilities was related to higher memory performance and positive personal beliefs regarding specific memory ability mediated relationship.

A Hybrid Swapping Scheme Based On Per-Process Reclaim for Performance Improvement of Android Smartphones (August 2018)

As a way to increase the actual main memory capacity of Android smartphones, most of them make use of zRAM swapping, but it has limitation in increasing its capacity since it utilizes main memory. Unfortunately, they cannot use secondary storage as a swap space due to the long response time and wear-out problem. In this paper, we propose a hybrid swapping scheme based on per-process reclaim that supports both secondary-storage swapping and zRAM swapping. It attempts to swap out all the pages in the working set of a process to a zRAM swap space rather than killing the process selected by a low-memory killer, and to swap out the least recently used pages into a secondary storage swap space. The main reason being is that frequently swap- in/out pages use the zRAM swap space while less frequently swap-in/out pages use the secondary storage swap space, in order to reduce the page operation cost. Our scheme resolves both the response time and wear-out problems of secondary-storage swapping and zSWAP, and overcomes the size limitation of the zRAM swap space. According to performance measurements, it also increased the extension ratio of main memory by 15 ~ 17% and 6 ~ 17% and reduced the page operation cost by 9 ~ 22% and 18 ~ 28%, respectively, compared with zRAM swapping and zSWAP.

Memory and the infrared

Memory effects in scattering processes are described in terms of the asymptotic retarded fields. These fields are completely determined by the scattering data and the zero mode part is set by the soft photon theorem. The dressed asymptotic states defining an infrared finite S-matrix for charged particles can be defined as quantum coherent states using the corpuscular resolution of the asymptotic retarded fields. Imposing that the net radiated energy in the scattering is zero leads to the new set of conservation laws for the scattering S-matrix which are equivalent to the decoupling of the soft modes. The actual observability of the memory requires a non-vanishing radiated energy and could be described using the infrared part of the differential cross section that only depends on the scattering data and the radiated energy. This is the IR safe cross section with any number of emitted photons carrying total energy equal to the energy involved in the actual memory detection.

Classical-nucleation-theory analysis of priming in chalcogenide phase-change memory

The chalcogenide Ge2Sb2Te5 (GST) is of interest for use in phase-change memory. Crystallization is the rate-limiting step for memory operation, and can be accelerated by the prior application of a “priming” heating pulse. There is characteristic fading of the priming effect if there is a time interval between the priming pulse and the main heating pulse to achieve crystallization. We apply classical nucleation theory to interpret these effects, based on a fitting of nucleation kinetics (steady-state and transient) over the full temperature range of the supercooled liquid. The input data come from both physical experiments and atomistic simulations. Prior studies of conventional glass-formers such as lithium disilicate preclude any possibility of fading; the present study shows, however, that fading can be expected with the particular thermodynamic parameters relevant for GST and, possibly, other phase-change chalcogenides. We also use the nucleation analysis to highlight the distinction between GST and the other archetypical chalcogenide system (Ag,In)-doped Sb2Te. Classical nucleation theory appears to be applicable to phase-change chalcogenides, and to predict performance consistent with that of actual memory cells. Nucleation modeling may therefore be useful in optimizing materials selection and performance in device applications.

ACTUAL MEMORY DECLINE MEDIATES THE EFFECT OF AMYLOID BURDEN ON SUBJECTIVE MEMORY IN COGNITIVELY NORMAL ADULTS

Evidence suggests that high amyloid burden is related to subjective memory complaints, and additional studies report that these complaints may indicate actual memory impairments. However, some studies on subjective memory have found that subjective complaints are more due to anxiety and worry, rather than actual memory decline. To date, studies have mostly relied on only single-domain measures about subjective memory, and have not examined whether the relationship between amyloid deposition and subjective memory is mediated by actual memory decline. To address this issue, we used a psychometrically-validated Metamemory in Adulthood questionnaire that explores seven dimensions of subjective memory, including knowledge and perceptions about their own memory capacity, memory decline, anxiety, etc. This allowed us to assess the relationship of amyloid deposition to different dimensions of subjective memory and whether actual memory performance was the basis for the beliefs concerning memory. A total of 85 cognitively-normal adults (ages 33–93) from the Dallas Lifespan Brain Study completed Florbetapir PET imaging and the Metamemory in Adulthood questionnaire. Subscales included evaluation of memory capacity, change/stability, anxiety, achievement, locus of control, task, and strategy. In a first step, mean cortical SUVR was used to predict subjective memory scores, after controlling for age and gender. In a second step, mediation analyses assessed whether the amyloid effects were mediated by actual memory performance using a composite of four episodic memory indicators. Higher mean cortical SUVR was associated with beliefs of lower capacity (Figure 1), lower stability/greater change (Figure 2), and greater anxiety (Figure 3). Importantly, participants’ beliefs about their memory was validated by the finding that actual memory performance mediated the relationship of amyloid to beliefs about memory capacity (Figure 4) and memory-related anxiety (Figure 5).

ACTUAL MEMORY DECLINE MEDIATES THE EFFECT OF AMYLOID BURDEN ON SUBJECTIVE MEMORY IN COGNITIVELY NORMAL ADULTS

Evidence suggests that high amyloid burden is related to subjective memory complaints, and additional studies report that these complaints may indicate actual memory impairments. However, some studies on subjective memory have found that subjective complaints are more due to anxiety and worry, rather than actual memory decline. To date, studies have mostly relied on only single-domain measures about subjective memory, and have not examined whether the relationship between amyloid deposition and subjective memory is mediated by actual memory decline. To address this issue, we used a psychometrically-validated Metamemory in Adulthood questionnaire that explores seven dimensions of subjective memory, including knowledge and perceptions about their own memory capacity, memory decline, anxiety, etc. This allowed us to assess the relationship of amyloid deposition to different dimensions of subjective memory and whether actual memory performance was the basis for the beliefs concerning memory. A total of 85 cognitively-normal adults (ages 33–93) from the Dallas Lifespan Brain Study completed Florbetapir PET imaging and the Metamemory in Adulthood questionnaire. Subscales included evaluation of memory capacity, change/stability, anxiety, achievement, locus of control, task, and strategy. In a first step, mean cortical SUVR was used to predict subjective memory scores, after controlling for age and gender. In a second step, mediation analyses assessed whether the amyloid effects were mediated by actual memory performance using a composite of four episodic memory indicators. Higher mean cortical SUVR was associated with beliefs of lower capacity (Figure 1), lower stability/greater change (Figure 2), and greater anxiety (Figure 3). Importantly, participants’ beliefs about their memory was validated by the finding that actual memory performance mediated the relationship of amyloid to beliefs about memory capacity (Figure 4) and memory-related anxiety (Figure 5).

The puzzle of study time allocation for the most challenging items.

Learners often allocate more study time to challenging items than to easier ones. Nevertheless, both predicted and actual memory performance are typically worse for difficult than for easier items. The resulting inverse relations between people's predictions of their memory performance (judgments of learning; JOLs) and self-paced study time (ST) are often explained by bottom-up, data-driven ST allocation that is based on fluency. However, we demonstrate robust inverted U-shaped relations between JOLs and ST that cannot be explained by data-driven ST allocation alone. Consequently, we explored how two models of top-down, strategic ST allocation account for curvilinear JOL-ST relations. First, according to the Region of Proximal Learning model, people stop quickly on items for which they experience too little progress in learning. Second, according to the Diminishing Criterion Model, people set a time limit and stop studying when this time limit is reached. In three experiments, we manipulated motivation with different methods and examined which model best described JOL-ST relations. Consistent with the Diminishing Criterion Model but not with the Region of Proximal Learning model, results revealed that curvilinearity was due to people setting a time limit.