Short-term Memory Storage Research Articles

Subjective Cognitive Impairment Can Be Detected from the Decline of Complex Cognition: Findings from the Examination of Remedes 4 Alzheimer's (R4Alz) Structural Validity.

To reveal the cognitive-control dimensions that can differentiate between adults and older adults with healthy cognition, people with subjective cognitive impairment, and people diagnosed with mild cognitive impairment by examining the factorial structure of the R4Alz tool. The study comprised 404 participants: (a) healthy adults (n = 192), (b) healthy older adults (n = 29), (c) people with SCI (n = 74), and (d) people diagnosed with MCI (n = 109). The R4Alz battery was administered to all participants, including tests that assess short-term memory storage, information processing, information updating in working memory, and selective, sustained and divided attention), task/rule-switching, inhibitory control, and cognitive flexibility. A two-factorial structural model was confirmed for R4Alz, with the first factor representing "fluid intelligence (FI)" and the second factor reflecting "executive functions (EF)". Both FI and EFs discriminate among all groups. The R4Alz battery presents sound construct validity, evaluating abilities in FI and EF. Both abilities can differentiate very early cognitive impairment (SCI) from healthy cognitive aging and MCI.

An oscillatory mechanism for multi-level storage in short-term memory

Oscillatory activity is commonly observed during the maintenance of information in short-term memory, but its role remains unclear. Non-oscillatory models of short-term memory storage are able to encode stimulus identity through their spatial patterns of activity, but are typically limited to either an all-or-none representation of stimulus amplitude or exhibit a biologically implausible exact-tuning condition. Here we demonstrate a simple mechanism by which oscillatory input enables a circuit to generate persistent or sequential activity that encodes information not only in the spatial pattern of activity, but also in the amplitude of activity. This is accomplished through a phase-locking phenomenon that permits many different amplitudes of persistent activity to be stored without requiring exact tuning of model parameters. Altogether, this work proposes a class of models for the storage of information in working memory, a potential role for brain oscillations, and a dynamical mechanism for maintaining multi-stable neural representations.

Intervention targeting different visual attention span components in Chinese children with developmental dyslexia: a study based on Bundesen's theory of visual attention.

Within the framework of the theory of visual attention (TVA), the visual attention span (VAS) deficit among individuals with developmental dyslexia has been ascribed to the problems entailed by bottom-up (BotU) and top-down (TopD) attentional processes. The former involves two VAS subcomponents: the visual short-term memory storage and perceptual processing speed; the latter consists of the spatial bias of attentional weight and the inhibitory control. Then, what about the influences of the BotU and TopD components on reading? Are there differences in the roles of the two types of attentional processes in reading? This study addresses these issues by using two types of training tasks separately, corresponding to the BotU and TopD attentional components. Three groups of Chinese children with dyslexia-15 children each in the BotU training, TopD training, and non-trained active control groups were recruited here. Participants completed reading measures and a CombiTVA task which was used to estimate VAS subcomponents, before and after the training procedure. Results showed that BotU training improved both the within-category and between-category VAS subcomponents and sentence reading performance; meanwhile, TopD training enhanced character reading fluency through improving spatial attention capacity. Moreover, benefits on attentional capacities and reading skills in the two training groups were generally maintained three months after the intervention. The present findings revealed diverse patterns in the influences of VAS on reading within the TVA framework, which contributes to enriching the understanding of VAS-reading relation.

Stokes’s malleability thesis and the normative grounding of propositional attitudes

The position that Stokes’s Thinking and Perceiving aims to overthrow is committed to the idea that the facts about one’s propositional attitudes and the facts about one’s perceptual experiences are alike grounded in facts about representations (in various formats) that are being held in a short or long term memory store, so that computations can be performed upon them. Claims about modularity are claims about the distinctness of these memory stores, and of these representations. One way in which to reject those claims is to deny only that distinctness. A more radical way would be to reject the underlying idea that facts about perception and facts about propositional attitudes are alike grounded in facts about stored representations. Although the more radical approach might seem to face a problem concerning causal efficacy, I suggest that the way is open for Stokes to take it.

Lower visual processing speed relates to greater subjective cognitive complaints in community-dwelling healthy older adults.

Subjective cognitive complaints in older age may reflect subtle objective impairments in basic cognitive functions that might foreshadow broader cognitive problems. Such cognitive functions, however, are not captured by standard neuropsychological testing. Visual processing speed is a basic visual attention function that underlies the performance of cognitive tasks relying on visual stimuli. Here, we test the hypothesis that lower visual processing speed correlates with greater subjective cognitive complaints in healthy older adults from the community. To do so, we assessed a sample of 30 healthy, cognitively normal older adults (73.07 ± 7.73 years old; range: 60-82; 15 females) with respect to individual subjective cognitive complaints and visual processing speed. We quantified the degree of subjective cognitive complaints with two widely-used questionnaires: the Memory Functioning Questionnaire and the Everyday Cognition. We used verbal report tasks and the theory of visual attention to estimate a visual processing speed parameter independently from motor speed and other visual attention parameters, i.e., visual threshold, visual short-term memory storage capacity, top-down control, and spatial weighting. We found that lower visual processing speed correlated with greater subjective complaints and that this relationship was not explained by age, education, or depressive symptoms. The association with subjective cognitive complaints was specific to visual processing speed, as it was not observed for other visual attention parameters. These results indicate that subjective cognitive complaints reflect a reduction in visual processing speed in healthy older adults. Together, our results suggest that the combined assessment of subjective cognitive complaints and visual processing speed has the potential to identify individuals at risk for cognitive impairment before the standard tests show any abnormal results.

The temporal cost of deploying attention limits accurate target identification in rapid serial visual presentation

Lag-1 sparing is a common exception to the attentional blink, where a target presented directly after T1 can be identified and reported accurately. Prior work has proposed potential mechanisms for lag 1 sparing, including the boost and bounce model and the attentional gating model. Here, we apply a rapid serial visual presentation task to investigate the temporal limitations of lag 1 sparing by testing three distinct hypotheses. We found that endogenous engagement of attention to T2 requires between 50 and 100 ms. Critically, faster presentation rates yielded lower T2 performance, whereas decreased image duration did not impair T2 detection and report. These observations were reinforced by subsequent experiments controlling for short-term learning and capacity-dependent visual processing effects. Thus, lag-1 sparing was limited by the intrinsic dynamics of attentional boost engagement rather than by earlier perceptual bottlenecks such as insufficient exposure to images in the stimulus stream or visual processing capacity limitations. Taken together, these findings support the boost and bounce theory over earlier models that focus only on attentional gating or visual short-term memory storage, informing our understanding of how the human visual system deploys attention under challenging temporal constraints.

Visual Working Memory Capacity in Patients with Temporal Lobe Glioma

Introduction: Working memory (WM) refers to the temporary storage and manipulation of information. Short-term memory storage can be divided into separate subsystems for verbal information and visual information. We explored the capacity of visual WM in patients with temporal lobe glioma. Methods: In this study, we assessed 30 patients with temporal lobe glioma and 30 healthy controls (HCs) using a method that combined memory tests with visual WM tasks (digital span task, spatial capacity N-back task, and emotional N-back task). Results: The results revealed that groups did not differ in terms of demographics, estimated intelligence, and level of psyc distress. For visual WM tasks, statistically significant differences were not found on the 1-back tasks and forward versions of simple span tasks between the temporal patient (TP) group and the HC group. Analysis of correct responses of the experimental tasks suggested that the TP group was significantly different from the HC group in the 2-back tasks and backward versions of simple span tasks. For reaction times, spatial capacity 2-back task and emotional 2-back task showed the TP group was significantly different from the HC group. Conclusion: These findings revealed that visual WM scores of temporal glioma patients were lower than HCs, and hence, the temporal lobe may be a certain neuroanatomical structure in the WM network.

Millimeter Wave Radar Combines Long Short-term Memory and Energy Storage Embedded System for On-street Parking Space Prediction

Millimeter Wave Radar Combines Long Short-term Memory and Energy Storage Embedded System for On-street Parking Space Prediction

Active Working Memory and Simple Cognitive Operations.

Working memory is thought to serve as a buffer for ongoing cognitive operations, even in tasks that have no obvious memory requirements. This conceptualization has been supported by dual-task experiments, in which interference is observed between a primary task involving short-term memory storage and a secondary task that presumably requires the same buffer as the primary task. Little or no interference is typically observed when the secondary task is very simple. Here, we test the hypothesis that even very simple tasks require the working memory buffer, but interference can be minimized by using activity-silent representations to store the information from the primary task. We tested this hypothesis using dual-task paradigm in which a simple discrimination task was interposed in the retention interval of a change detection task. We used contralateral delay activity (CDA) to track the active maintenance of information for the change detection task. We found that the CDA was massively disrupted after the interposed task. Despite this disruption of active maintenance, we found that performance in the change detection task was only slightly impaired, suggesting that activity-silent representations were used to retain the information for the change detection task. A second experiment replicated this result and also showed that automated discriminations could be performed without producing a large CDA disruption. Together, these results suggest that simple but non-automated discrimination tasks require the same processes that underlie active maintenance of information in working memory.

Latching dynamics as a basis for short-term recall.

We discuss simple models for the transient storage in short-term memory of cortical patterns of activity, all based on the notion that their recall exploits the natural tendency of the cortex to hop from state to state-latching dynamics. We show that in one such model, and in simple spatial memory tasks we have given to human subjects, short-term memory can be limited to similar low capacity by interference effects, in tasks terminated by errors, and can exhibit similar sublinear scaling, when errors are overlooked. The same mechanism can drive serial recall if combined with weak order-encoding plasticity. Finally, even when storing randomly correlated patterns of activity the network demonstrates correlation-driven latching waves, which are reflected at the outer extremes of pattern space.

Semantic influence on visual working memory of object identity and location

Does semantic information—in particular, regularities in category membership across objects—influence visual working memory (VWM) processing? We predict that the answer is “yes”. Four experiments evaluating this prediction are reported. Experimental stimuli were images of real-world objects arranged in either one or two spatial clusters. On coherent trials, all objects belonging to a cluster also belonged to the same category. On incoherent trials, at least one cluster contained objects from different categories. Experiments using a change-detection paradigm (Experiments 1–3) and an experiment in which participants recalled the locations of objects in a scene (Experiment 4) yielded the same result: participants showed better memory performance on coherent trials than on incoherent trials. Taken as a whole, these experiments provide the best (perhaps only) data to date demonstrating that statistical regularities in semantic category membership improve VWM performance. Because a conventional perspective in cognitive science regards VWM as being sensitive solely to bottom-up visual properties of objects (e.g., shape, color, orientation), our results indicate that cognitive science may need to modify its conceptualization of VWM so that it is closer to “conceptual short-term memory”, a short-term memory store representing current stimuli and their associated concepts (Potter, 1993, 2012).

Dark Sweet Cherry (DSC) Juice Consumption for Obesity-Related Inflammation and Cognitive Function in Obese Adults: A Human Clinical Pilot Trial

ObjectivesTo assess the effects of DSC juice on biomarkers of obesity-related metabolic disorders, inflammation, and cognitive performance. MethodsEligible participants (>18, body-mass index (BMI) = 30–40 kg/m2, no history of chronic disease and/or medication/antibiotics), were assigned to cherry or placebo groups following a single-blind randomized design after a 2-week run-in period. Participants were asked to drink 200 mL cherry juice supplemented with 3 g DSC powder (n = 11) or placebo drink (n = 10) twice a day for 30 days. Wellness check, anthropometric measurements, cognitive function/psychological assessments, and fasting blood samples were collected at study days 1 and 30. ResultsBaseline data showed no differences in anthropometric measurements between experimental groups. Results from blood markers of liver and metabolic disorders showed no difference between end point and baseline values for both cherry and placebo groups. However, median (25%, 75% interquartile) values for erythrocyte sedimentation rate (ESR) and reactive oxygen species (ROS) at day 30 (ESR = 6 (4, 13), ROS = 29 (13, 53) showed improvement compared to day 1 (ESR = 7 (2, 16), ROS = 33 (21, 65)) in cherry group, while in placebo group values showed less or no improvement (ESR = 12 (8, 24), ROS = 30 (20, 72) at day 30), vs (ESR = 10 (7, 18), ROS = 37 (29, 75) at day 1). These results suggest an anti-inflammatory cherry juice action and may be correlated with a trend for improvement in all of the cognitive tasks and physiological assessments in cherry group. The trail making tests (A and B), which assess executive functioning, improved (P = 0.0273 and P = 0.0342, respectively) as well as the Digit Span Forward task (DSF) (P = 0.0137), which examines short-term memory storage and executive control processes. The Digit Symbol Substitution test (DSST) used to assess processing speed, sustained attention and working memory showed improvement for cherry group, although non-significant (P = 0.0527). ConclusionsThese preliminary findings suggest that consumption of DSC juice rich in anthocyanins and other phytochemicals over 4 weeks may improve cognitive function in obese participants with possible link to lowered inflammation. Funding SourcesThis work was supported by the Northwest Cherry Growers.

Reduced perceptual processing speed and atypical attentional weight at the cores of visual simultaneous processing deficits in Chinese children with developmental dyslexia: a parameter-based assessment of visual attention

Individuals with developmental dyslexia usually exhibit a problem in simultaneous processing of multiple visual elements. However, the relationship between impaired visual simultaneous processing (VSP) and reading difficulty is still debated. These inconsistencies may be associated with a wide range of participants’ age, variation in orthographic depth of background languages, and complex subcomponents underlying VSP. The present study thus examined the VSP capacity of children with dyslexia in the language context of Chinese (i.e., a logographic writing system with deep orthography) through the developmental trajectories method in which participants’ age was considered as a continuous variable. This visual multiple-element processing skill was fractionated into four parameters (processing speed, visual short-term memory storage, attentional weight, and irrelevant inhibition) within the framework of the theory of visual attention (TVA). Forty-seven children with dyslexia and fifty-three age-matched normal readers from primary schools were recruited to take a combined TVA test using symbols as non-verbal stimuli. Results showed that the developmental trajectories of children with dyslexia exhibited a delayed pattern in perceptual processing speed and an atypical pattern in attentional weight compared to the controls. Further mediation analyses showed the triangular relationship of “TVA subcomponent-linguistic awareness-reading,” revealing the possible roles of these subcomponents regarding VSP in Chinese reading. The current findings suggested that the VSP deficit of Chinese children with dyslexia may stem from impairments in perceptual processing speed and attentional weight, revealing the possible modulation of language specificity (i.e., Chinese) on cognitive deficits of dyslexia, which may have implications for the diagnosis and remediation of dyslexia.

Short- and long-term memory of moving amoeboid cells.

Amoeboid cells constantly change shape and extend protrusions. The direction of movement is not random, but is correlated with the direction of movement in the preceding minutes. The basis of this correlation is an underlying memory of direction. The presence of memory in movement is known for many decades, but its molecular mechanism is still largely unknown. This study reports in detail on the information content of directional memory, the kinetics of learning and forgetting this information, and the molecular basis for memory using Dictyostelium mutants. Two types of memory were characterized. A short-term memory stores for ~20 seconds the position of the last pseudopod using a local modification of the branched F-actin inducer SCAR/WAVE, which enhances one new pseudopod to be formed at the position of the previous pseudopod. A long term memory stores for ~2 minutes the activity of the last ~10 pseudopods using a cGMP-binding protein that induces myosin filaments in the rear of the cell; this inhibits pseudopods in the rear and thereby enhances pseudopods in the global front. Similar types of memory were identified in human neutrophils and mesenchymal stem cells, the protist Dictyostelium and the fungus B.d. chytrid. The synergy of short- and long-term memory explains their role in persistent movement for enhanced cell dispersal, food seeking and chemotaxis.

Novelty Detection in Memory for Common and Uncommon Odors over Short Delays.

Odor memory is commonly believed to be very strong and long-lasting. The present study examined factors that impact odor recognition memory over short delay intervals (immediately or 30 s after target presentation) with emphasis on memory task (forced-choice vs "monadic"/single stimulus yes/no), odor category, and target/foil relationship. We explored trial-by-trial confidence as well as the effect of target familiarity, pleasantness, and intensity ratings, and odor nameability on memory for odors. Overall odor recognition memory in terms of proportion correct and sensitivity measures did not decline significantly during the 30-s delay interval in either task. However, hit rates were lower at 30 s and correct rejection rates for common odors remained consistently high. Recognition memory was better on trials in which the odor pairs were highly dissimilar, as well as on trials in which the target was an uncommon odor, particularly if it could be named. Familiarity, pleasantness, and intensity had no systematic effect on recognition memory. Whereas the results provide evidence of a fading memory trace, indicated by the decreased hit rates after a 30-s delay, the constant rates of correct rejections and high confidence ratings on those trials, even after delay, suggests that novelty detection (i.e., recognition that an odor is not one that has been encountered previously in that context) may play an important role in the memory for odors over short delays. Whether there is a separate short-term odor memory store is also addressed.

CSLM: Convertible Short-Term and Long-Term Memory in Differential Neural Computers

External memory-based neural networks, such as differentiable neural computers (DNCs), have recently gained importance and popularity to solve complex sequential learning tasks that pose challenges to conventional neural networks. However, a trained DNC usually has a low-memory utilization efficiency. This article introduces a variation of DNC architecture with a convertible short-term and long-term memory, named CSLM-DNC. Unlike the memory architecture of the original DNC, the new scheme of short-term and long-term memories offers different importance of memory locations for read and write, and they can be converted over time. This is mainly motivated by the human brain where short-term memory stores large amounts of noisy and unimportant information and decays rapidly, while long-term memory stores important information and lasts for a long time. The conversion of these two types of memory is allowed and is able to be learned according to their reading and writing frequency. We quantitatively and qualitatively evaluate the proposed CSLM-DNC architecture on the tasks of question answering, copy and repeat copy, showing that it can significantly improve memory efficiency and learning performance.

ADHD and hyperactivity: The influence of cognitive processing demands on gross motor activity level in children

ABSTRACT Excessive gross motor activity is a prominent feature of children with ADHD, and accruing evidence indicates that their gross motor activity is significantly higher in situations associated with high relative to low working memory processing demands. It remains unknown, however, whether children’s gross motor activity rises to an absolute level or accelerates incrementally as a function of increasingly more difficult cognitive processing demands imposed on the limited capacity working memory (WM) system – a question of both theoretical and applied significance. The present investigation examined the activity level of 8- to 12-year-old children with ADHD (n = 36) and Typically Developing (TD) children (n = 24) during multiple experimental conditions: a control condition with no storage and negligible WM processing demands; a short-term memory (STM) storage condition; and a sequence of WM conditions that required both STM and incrementally more difficult higher-order cognitive processing. Relative to the control condition, all children, regardless of diagnostic status, exhibited higher levels of gross motor activity while engaged in WM tasks that required STM alone and STM combined with upper level cognitive processing demands, and children with ADHD were motorically more active under all WM conditions relative to TD children. The increase in activity as a consequence of cognitive demand was similar for all experimental conditions. Findings suggest that upregulation of physical movement rises and remains relatively stable to promote arousal related mechanisms when engaged in cognitive activities involving WM for all children, and to a greater extent for children with ADHD.

Visual Attention Modulates Phenomenal Consciousness: Evidence From a Change Detection Study.

The distinction between phenomenal and access consciousness has been influential in the field of consciousness studies. Both Block and Lamme proposed that access consciousness, or narrow cognitive accessibility, is related to a limited capacity working memory, and that phenomenal consciousness, or broad cognitive accessibility, is related to iconic memory or, more recently, to a fragile (intermediate) short-term memory store with a larger capacity than working memory. They have also highlighted the preattentive nature of phenomenal consciousness and of the related iconic and fragile visual short-term stores, thus selectively linking attention with access consciousness, in line with Baars and Dehaene, among others. However, a range of electrophysiological and neurophysiological studies suggest that visual attention can affect early responses of neurons in visual cortex, before conscious access. Furthermore, some theories and neurocomputational models suggest earlier attentional biases related to phenomenal consciousness. To solve this controversy, and to shed light on the relationships of attention with iconic memory and subsequent stages of visual maintenance, we conducted an experiment with a novel procedure of change detection based on delayed cueing of the target for report with high- and low-priority objects marked by color. In line with our hypothesis, the results show an attentional bias toward high-priority objects in the memory array with the longer (600 and 1,200 ms) cueing delays associated with a fragile (intermediate) visual short-term memory, but not with the shorter cueing delays (16.6 and 200 ms) associated with iconic memory. These findings therefore suggest two stages of phenomenal consciousness before access consciousness: a first preattentive stage related to iconic memory and a second stage related to fragile visual short-term memory intermediate between iconic and visual working memory, which is modulated by visual attention in a time-dependent manner. Finally, our results suggest the dissociation between a mid-level visual attention modulating phenomenal consciousness and a central attention directing access consciousness.

Common cortical architectures for phonological working memory identified in individual brains

Phonological working memory is the capacity to briefly maintain and recall representations of sounds important for speech and language and is believed to be critical for language and reading acquisition. Whether phonological working memory is supported by fronto-parietal brain regions associated with short-term memory storage or perisylvian brain structures implicated in speech perception and production is unclear, perhaps due to variability in stimuli, task demands, and individuals. We used fMRI to assess neurophysiological responses while individuals performed two tasks with closely matched stimuli but divergent task demands—nonword repetition and nonword discrimination—at two levels of phonological working memory load. Using analyses designed to address intersubject variability, we found significant neural responses to the critical contrast of high vs. low phonological working memory load in both tasks in a set of regions closely resembling those involved in speech perception and production. Moreover, within those regions, the voxel-wise patterns of load-related activation were highly correlated between the two tasks. These results suggest that brain regions in the temporal and frontal lobes encapsulate the core neurocomputational components of phonological working memory; an architecture that becomes increasingly evident as neural responses are examined in successively finer-grained detail in individual participants.

Short-term memory based on activated long-term memory: A review in response to Norris (2017).

Short-term memory (STM), the limited information temporarily in a state of heightened accessibility, includes just-presented events and recently retrieved information. Norris (2017) argued for a prominent class of theories in which STM depends on the brain keeping a separate copy of new information, and against alternatives in which the information is held only in a portion of long-term memory (LTM) that is currently activated (aLTM). Here I question premises of Norris' case for separate-copy theories in the following ways. (a) He did not allow for implications of the common assumption (e.g., Cowan, 1999; Cowan & Chen, 2009) that aLTM can include new, rapidly formed LTM records of a trial within an STM task. (b) His conclusions from pathological cases of impaired STM along with intact LTM are tenuous; these rare cases can be explained by impairments in encoding, processing, or retrieval related to LTM rather than passive maintenance. (c) Although Norris reasonably allowed structured pointers to aLTM instead of separate copies of the actual item representations in STM, the same structured pointers may well be involved in long-term learning. (d) Last, models of STM storage can serve as the front end of an LTM learning system rather than being separate. I summarize evidence for these premises and an updated version of an alternative theory in which storage depends on aLTM (newly clarified), and, embedded within it, information enhanced by the current focus of attention (Cowan, 1988, 1999), with no need for a separate STM copy. (PsycINFO Database Record (c) 2019 APA, all rights reserved).