Memory Maintenance Research Articles

Differential effects of executive load on automatic versus controlled semantic memory retrieval.

Growing evidence indicates that a domain-general executive control supports semantic memory retrieval, yet the nature of this interaction remains elusive. To shed light on such control mechanisms, we conducted two dual-task experiments loading distinct executive capacities (working memory maintenance, monitoring, and switching), while participants carried out automatic (free-associative) and controlled (dissociative) word retrieval tasks. We found that these forms of executive load interfered with retrieval fluency in both tasks, but these negative effects were more pronounced for the dissociative performance. Together, these findings indicate that the domain-general executive control supports accessing contextually relevant knowledge as well as the inhibition of automatically activated but task-inappropriate retrieval candidates, putatively via an adaptive gating of semantic activation and interference control. Moreover, the processing costs related to retrieval inhibition and switching were negatively correlated, suggesting a trade-off between the ability to constrain semantic activation (i.e., inhibition) and the ability to initiate flexible transitions between semantic sets (i.e., switching), which may thus represent two complementary control functions governing semantic memory retrieval.

Blockade of D-serine signaling and adult hippocampal neurogenesis attenuates remote contextual fear memory following multiple memory retrievals in male mice.

The retrieval of fear memories induces two opposing processes, reconsolidation, and extinction. The memory reconsolidation is an active process that involves gene expression and updates an existing memory. It is hypothesized that blockade of reconsolidation by manipulating the neurobiological factors, which are mechanistically involved in the process, could weaken or disrupt the original fear memory. The N-methyl-D-aspartate (NMDA) receptor and hippocampal neurogenesis play crucial roles in hippocampus-dependent memory processes, including reconsolidation. Using contextual fear conditioning paradigm with multiple retrievals, we attempted to weaken the original contextual fear memory by repeatedly disrupting retrieval-induced reconsolidation via downregulation of NMDA receptor signaling and inhibition of neurogenesis. In the first experiment, prior to fear conditioning, NMDA receptor signaling was downregulated by the genetic reduction of its co-agonist, D-serine, and the neurogenesis was dampened by focal X-ray irradiation on the hippocampus. We found that simultaneous D-serine reduction and neurogenesis dampening resulted in a progressive decrease in freezing following each retrieval, leading to an attenuation of remote contextual fear memory on day 28. In the second experiment using the same behavioral protocols, after conditioning, pharmacological approaches were conducted to simultaneously block D-serine signaling and neurogenesis, resulting in a similar suppressive effect on the remote fear memory. The present findings provide insights for understanding the role of D-serine-mediated NMDA receptor signaling and neurogenesis in memory retrieval and the maintenance of remote fear memory, and improving the efficacy of exposure-based therapy for the treatment of post-traumatic stress disorder (PTSD).

The maintenance and transmission of memory through media : a murder in broadside ballads, news periodicals, and oral tradition

This study uses a 1907 quadruple homicide to present the different ways that information was presented by broadside ballads, news periodicals, and the oral tradition. Broadside ballads, which were akin to tabloid journalism and commemorated important events as one-page hard-copies of song lyrics, were losing popularity at the time, and news periodicals, like newspapers and magazines, represented the most accessible source of information for the broader social strata. Both helped to transmit and, later, maintain the memory of the infamous crime. This text focuses on similarities and differences in the reporting, including the choice of topic, sourcing, transmission of information, work with audiences, and authorship. Drawing on primary sources and present-day recapitulations, it analyses the ways in which memory was maintained (and not maintained) through these media. In addition, the study analyses the passage of information through oral folk tradition and collective and community memory, and their mutual influences.

Astrocyte and Neuronal Panx1 Support Long-Term Reference Memory in Mice.

Pannexin 1 (Panx1) is an ubiquitously expressed protein that forms plasma membrane channels permeable to anions and moderate-sized signaling molecules (e.g., ATP, glutamate). In the nervous system, activation of Panx1 channels has been extensively shown to contribute to distinct neurological disorders (epilepsy, chronic pain, migraine, neuroAIDS, etc.), but knowledge of the extent to which these channels have a physiological role remains restricted to three studies supporting their involvement in hippocampus dependent learning. Given that Panx1 channels may provide an important mechanism for activity-dependent neuron-glia interaction, we used Panx1 transgenic mice with global and cell-type specific deletions of Panx1 to interrogate their participation in working and reference memory. Using the eight-arm radial maze, we show that long-term spatial reference memory, but not spatial working memory, is deficient in Panx1-null mice and that both astrocyte and neuronal Panx1 contribute to the consolidation of long-term spatial memory. Field potential recordings in hippocampal slices of Panx1-null mice revealed an attenuation of both long-term potentiation (LTP) of synaptic strength and long-term depression (LTD) at Schaffer collateral-CA1 synapses without alterations of basal synaptic transmission or pre-synaptic paired-pulse facilitation. Our results implicate both neuronal and astrocyte Panx1 channels as critical players for the development and maintenance of long-term spatial reference memory in mice.

A preservação do patrimônio ferroviário através da revitalização para o uso turístico: um estudo das estações ferroviárias de Canela e Passo Fundo, Brasil

The general objective of this study is to analyse how the revitalisation of Canela and Passo Fundo railway stations and their use by tourists contribute to the preservation of railway memory and railway heritage. Specifically, it intends to identify what configures stations as heritage; to understand the role of tourism in the use and preservation of revitalised spaces and to understand how revitalisation contributes to the maintenance of railway memory. Using a comparative‑descriptive method, the study analyses the two stations from three analytical perspectives: the attribution of use and utilisation of spaces, legibility and railway memory. The revitalisation thanks to tourism provided a greater use of spaces, with increased traf‑ fic and flows. Tourism does not invalidate the heritage character of the stations, but rather reinforces it by allowing people to have contact with these places through public use.

Auricular transcutaneous vagus nerve stimulation specifically enhances working memory maintenance – a system neurophysiological study

Auricular transcutaneous vagus nerve stimulation specifically enhances working memory maintenance – a system neurophysiological study

Attentional distraction affects maintenance of information in visual sensory memory

Classical theoretical models suggest that visual short-term memory can be divided in two main memory systems: sensory memory, a short-lasting but high-capacity memory storage and working memory, a long-lasting but low-capacity memory store. Whilst, previous research has systematically shown a strong interplay between attentional mechanisms and working memory, less clear is the role of attention in sensory memory. In the present study we approach this issue by asking whether withdrawing attentional resources by a dual task (Experiment 1) or by presenting task irrelevant information during memory maintenance (Experiment 2 and 3) similarly or differently affect sensory and working memory. Overall, results showed that sensory memory content was undermined not only by a simultaneous high-demanding cognitive task but even when purely task-irrelevant and non-masking visual distractors were presented during maintenance. Our data provide support against theories that consider sensory memories as a case of visual awareness free of attention.

NCK1 Modulates Neuronal Actin Dynamics and Promotes Dendritic Spine, Synapse, and Memory Formation.

Memory formation and maintenance is a dynamic process involving the modulation of the actin cytoskeleton at synapses. Understanding the signaling pathways that contribute to actin modulation is important for our understanding of synapse formation and function, as well as learning and memory. Here, we focused on the importance of the actin regulator, noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1), in hippocampal dependent behaviors and development. We report that male mice lacking NCK1 have impairments in both short-term and working memory, as well as spatial learning. Additionally, we report sex differences in memory impairment showing that female mice deficient in NCK1 fail at reversal learning in a spatial learning task. We find that NCK1 is expressed in postmitotic neurons but is dispensable for neuronal proliferation and migration in the developing hippocampus. Morphologically, NCK1 is not necessary for overall neuronal dendrite development. However, neurons lacking NCK1 have lower dendritic spine and synapse densities in vitro and in vivo EM analysis reveal increased postsynaptic density (PSD) thickness in the hippocampal CA1 region of NCK1-deficient mice. Mechanistically, we find the turnover of actin-filaments in dendritic spines is accelerated in neurons that lack NCK1. Together, these findings suggest that NCK1 contributes to hippocampal-dependent memory by stabilizing actin dynamics and dendritic spine formation.SIGNIFICANCE STATEMENT Understanding the molecular signaling pathways that contribute to memory formation, maintenance, and elimination will lead to a better understanding of the genetic influences on cognition and cognitive disorders and will direct future therapeutics. Here, we report that the noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) adaptor protein modulates actin-filament turnover in hippocampal dendritic spines. Mice lacking NCK1 show sex-dependent deficits in hippocampal memory formation tasks, have altered postsynaptic densities, and reduced synaptic density. Together, our work implicates NCK1 in the regulation of actin cytoskeleton dynamics and normal synapse development which is essential for memory formation.

Home Movie as a Text of Cultural Memory

The aim of this article is to define home movie as a text of cultural memory and reveal the dynamics of its meanings in culture. The personal and the collective maintenance and transmission of memory is a complex mechanism that operates within a dynamic cultural model. The analysis of this mechanism considers the way in which something that first appears to be culturally irrelevant – a private home movie of a family – is brought into the public space and circulates as a cultural text contributing to the preservation and formation of cultural memory. The analysis describes home movie in the framework of semiotics and reveals the meaning shifts that occur when private memory texts begin to circulate in a more general cultural context. The mechanism of the dynamics of cultural texts and the problematics of memory are explored using Yuri Lotman’s cultural semiotics approach. The example of Lithuanian director’s Dovilė Šarutytė’s debut feature film A Feature Film About Life (2021) is used to describe in more detail the transformations of meaning that home movies undergo after becoming a cultural text.

Result of a Questionnaire Survey of 61 Females on their Satisfaction with Fish, Calcium and Protein Intake

Since the calcium intake has not reached the target amount of 600 ~ 800 mg per day in the Japanese diet, calcium intake is recommended in the daily diet. And in recent years, Japan has been promoting protein intake for the elderly to prevent sarcopenia and frailty. Japan also recommended to take EPA and DHA to maintain smooth blood vessels and memory maintenance. Therefore, as a first step to understanding the actual situation, this study conducted a questionnaire survey on the information of fish rich in EPA and DHA and the intake of Ca and protein. Sixty-one participants were given a self-anubnustered questionnaire regarding fish, calcium and protein intake. The questionnaire method is self-administered, and the questions are about age, height, weight, and desired purchase price of fish. We asked the following questions, frequency of eating fish, frequency of eating meat, frequency of eating eggs, and frequency of eating bean products.

The spectrum of tuberculosis described as differential DNA methylation patterns in alveolar macrophages and alveolar T cells

BackgroundHost innate immune cells have been identified as key players in the early eradication of Mycobacterium tuberculosis and in the maintenance of an anti-mycobacterial immune memory, which we and others have shown are induced through epigenetic reprogramming. Studies on human tuberculosis immunity are dominated by those using peripheral blood as surrogate markers for immunity. We aimed to investigate DNA methylation patterns in immune cells of the lung compartment by obtaining induced sputum from M. tuberculosis- exposed subjects including symptom-free subjects testing positively and negatively for latent tuberculosis as well as patients diagnosed with active tuberculosis. Alveolar macrophages and alveolar T cells were isolated from the collected sputum and DNA methylome analyses performed (Illumina Infinium Human Methylation 450 k).ResultsMultidimensional scaling analysis revealed that DNA methylomes of cells from the tuberculosis-exposed subjects and controls appeared as separate clusters. The numerous genes that were differentially methylated between the groups were functionally connected and overlapped with previous findings of trained immunity and tuberculosis. In addition, analysis of the interferon-gamma release assay (IGRA) status of the subjects demonstrated that the IGRA status was reflected in the DNA methylome by a unique signature.ConclusionsThis pilot study suggests that M. tuberculosis induces epigenetic reprogramming in immune cells of the lung compartment, reflected as a specific DNA methylation pattern. The DNA methylation signature emerging from the comparison of IGRA-negative and IGRA-positive subjects revealed a spectrum of signature strength with the TB patients grouping together at one end of the spectrum, both in alveolar macrophages and T cells. DNA methylation-based biosignatures could be considered for further development towards a clinically useful tool for determining tuberculosis infection status and the level of tuberculosis exposure.

Considering Readout to Understand Working Memory.

While working memory (WM) allows us to store past information, its function is to guide future behavior. Given this role, the tight link between how WMs are maintained and how they are read out to be transformed into context-appropriate actions remains relatively unexplored. Beyond helping us understand memory-guided behavior, focusing on WM readout may also help us better understand the neural basis of memory maintenance.

A (further) test of spontaneous serial refreshing in verbal and spatial working memory

Working memory is the cognitive system that keeps a limited amount of information temporarily accessible for ongoing cognition. One proposed mechanism to keep information active in working memory is refreshing. Refreshing is assumed to operate serially, reactivating memory items one by one by bringing them into the focus of attention during retention. We report two experiments in which we examine evidence for the spontaneous occurrence of serial refreshing in verbal working memory (Experiment 1, using letters as memoranda) and in visuospatial working memory (Experiment 2, using locations as memoranda). Participants had to remember series of red memory items, and black probes were presented between these memory items, with each probe to be judged present in or absent from the list presented so far, as quickly as possible (i.e., the probe-span task). Response times to the probes were used to examine whether the content of the focus of attention changed over time, as would be expected if serial refreshing occurs spontaneously during interitem pauses. Contrary to this hypothesis, our results indicate that the last-presented memory item remained in the focus of attention during the interitem pauses of the probe-span tasks. These findings confirm the boundary conditions of spontaneous serial refreshing that were previously observed for verbal working memory and extend them to visuospatial working memory. Implications for working memory maintenance are discussed.

Brain Connectivity: A Journal of Clinical Neurology, Neuroscience, & Neuroimaging Advancing the Field of Neurology

<i>Brain Connectivity: A Journal of Clinical Neurology, Neuroscience, &amp; Neuroimaging</i> Advancing the Field of Neurology

Acute and protocol-dependent effects of aerobic exercise on neurobiochemical indices and neuropsychological performance of working memory

This study aimed to clarify the effects of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) protocols on peripheral neurotransmitters and on the neuropsychological performance of working memory and to explore underlying correlations. In a randomised cross-over trial, twenty-two adults in late middle age or older completed a single session of HIIE, MICE, or a control condition (rest) in counterbalanced order with a 7-day washout. Neuropsychological indices of working memory and neurotransmitter (norepinephrine, dopamine, and serotonin) levels were measured at baseline and after an intense bout of either HIIE or MICE, or an intervention without exercise. Analyses of the results revealed no significant effect of HIIE on the neurotransmitters, but significantly high levels of norepinephrine and serotonin were induced by MICE. In terms of neuropsychological performance, a single session of HIIE and MICE shortened the participants' reaction times (RTs), whereas only MICE caused a significant increase in accuracy rates (ARs). Significant correlations were found between the changes in norepinephrine levels and ARs/RTs before and after the HIIE and MICE interventions, respectively. The results of this study suggest that an intense MICE protocol triggers higher norepinephrine and serotonin levels than HIIE does. The possible neurobiochemical factor (i.e., norepinephrine) underlying the HIIE/MICE-induced neuropsychological benefits (i.e., improved ARs and RTs) for working memory encoding and maintenance appears to be protocol-dependent. Systematic and prolonged investigations are required to further understand the effects/mechanisms specific to each exercise protocol in order to optimize the benefits of aerobic exercise interventions for long-term neurobiochemical and neuropsychological health.

BAM15 Relieves Neurodegeneration in Aged Caenorhabditis elegans and Extends Lifespan.

BAM15 was recently screened as a protonophore uncoupler specifically for the mitochondrial membrane but not the plasma membrane. It is equally as potent as FCCP, but less toxic. Previously, mitochondrial uncoupling via DNP alleviates neurodegeneration in the nematode Caenorhabditis elegans during aging. Therefore, we investigated whether BAM15 uncouplers could phenotypically and functionally reduce neuronal defects in aged nematodes. We observed green fluorescence protein-tagged mechanosensory neurons and performed touch and chemotaxis assays during aging. Wild-type animals treated with both 50 µM BAM15 and 10 µM DNP showed reduced mechanosensory neuronal defects during aging, which correlates with the maintenance of touch responses and short-term memory during aging. Uncoupler mutant ucp-4 also responded the same way as the wild-type, reducing neurodegeneration in 50 µM BAM15 and 10 µM DNP-treated animals compared to the DMSO control. These results suggest that 50 µM BAM15 alleviates neurodegeneration phenotypically and functionally in C. elegans during aging, potentially through mitochondrial uncoupling. In accordance with the preserved neuronal shape and function in aged C. elegans, 50 µM BAM15 extended the mean lifespan of both wild-type and ucp-4 mutants.

The molecular diversity of plasticity mechanisms underlying memory: An evolutionary perspective.

Experience triggers molecular cascades in organisms (learning) that lead to alterations (memory) to allow the organism to change its behavior based on experience. Understanding the molecular mechanisms underlying memory, particularly in the nervous system of animals, has been an exciting scientific challenge for neuroscience. We review what is known about forms of neuronal plasticity that underlie memory highlighting important issues in the field: (1) the importance of being able to measure how neurons are activated during learning to identify the form of plasticity that underlies memory, (2) the many distinct forms of plasticity important for memories that naturally decay both within and between organisms, and (3) unifying principles underlying the formation and maintenance of long-term memories. Overall, the diversity of molecular mechanisms underlying memories that naturally decay contrasts with more unified molecular mechanisms implicated in long-lasting changes. Despite many advances, important questions remain as to which mechanisms of neuronal plasticity underlie memory.

Never forget? Memory maintenance on an aging platform

This article addresses the intersection between platforms, their sociotechnical process of aging and memory practice, by focusing on local social platform OakdaleTalk and its use in reflecting on September 11, 2001. Founded in 1997, OakdaleTalk serves the town of Oakdale in New Jersey, a place significantly affected by the attack on the World Trade Center in 2001. Situated in literature on digital memory work, this analysis draws on interviews with 15 OakdaleTalk members who have used the platform to reflect on September 11th. Asking how users maintain particular meanings of this date while negotiating sociotechnical changes to the site over time – including the loss of posts from 2001 – it discusses how users perpetuate hyperlocal interpretation and describes how community members grapple with lost content. The article concludes by proposing a ‘preservation paradox’, an emerging memory practice under platformized media conditions describing a contradiction in user preservation attitudes and behaviors toward posts of memory-related significance.

Transient active zone remodeling in the Drosophila mushroom body supports memory

Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.

Biologics as novel therapeutics for the treatment of allergy: Challenges and opportunities

Over the last 4 decades there has been a significant global increase in the incidence and prevalence of IgE-mediated allergy. Although much progress has been made in the management of allergy via patient education, pharmacotherapy and immunomodulatory treatment regimens, significant unmet need remains. Advancements in our knowledge base surrounding the type 2 immune response, production of IgE and maintenance of immunological memory has led the field to explore targeted intervention of allergic pathways using monoclonal antibodies (mAbs). Intervention at various stages of the allergic cascade offers the opportunity to prevent initiation and/or maintenance of the type 2 immune response and effectively provide therapeutic benefit to patients. Furthermore, a better understanding of the protective mechanisms involved in allergen specific immunotherapy (AIT) has led us to appreciate the interplay of immunoglobulins in the allergic response, specifically the benefit in shifting the IgG:IgE ratio in favor of functionally relevant blocking IgG. Thus, treatments that lower IgE or boost IgG with the ability to outcompete IgE binding to allergen also present a favorable approach in the treatment of allergy. In this short review we discuss and highlight recent advances in the use of biologics to treat severe allergy, highlighting the key challenges but also the significant opportunities and advances to date.