Memory Signal Research Articles

Modeling face similarity in police lineups.

Police investigators worldwide use lineups to test an eyewitness's memory of a perpetrator. A typical lineup consists of one suspect (who is innocent or guilty) plus five or more fillers who resemble the suspect and who are known to be innocent. Although eyewitness identification decisions were once biased by police pressure and poorly constructed lineups, decades of social science research led to the development of reformed lineup procedures that provide a more objective test memory. Under these improved testing conditions, cognitive models of memory can be used to better understand and ideally enhance eyewitness identification performance. In this regard, one question that has bedeviled the field for decades is how similar the lineup fillers should be to the suspect to optimize performance. Here, we model the effects of manipulating filler similarity to better understand why such manipulations have the intriguing effects they do. Our findings suggest that witnesses rely on a decision variable consisting of the degree to which the memory signal for a particular face in the lineup stands out relative to the crowd of memory signals generated by the set of faces in the lineup. The use of that decision variable helps to explain why discriminability is maximized by choosing fillers that match the suspect on basic facial features typically described by the eyewitness (e.g., age, race, gender) but who otherwise are maximally dissimilar to the suspect. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Bacillus Calmette-Guérin-induced interleukin-10 inhibits S100A8/A9 production and hinders development of T helper type 1 memory in mice.

Tuberculosis caused by Mycobacterium tuberculosis (M.tb)is one of the main causes of human death in the world. Bacillus Calmette-Guérin (BCG) provides limited protection in adolescents and adults. To explore the factors reducing efficacy of BCG vaccine, we assess the impacts of interleukin (IL)-10 and alarmins S100A8/A9 on T-cell memory. We found that BCG-induced IL-10 inhibited production of S100A8/A9 in human peripheral blood mononuclear cells (PBMCs) and murine splenocytes. S100A9 deficiency inhibited IFN-γ production by CD4+ T cells in the early phase of BCG immunization and hindered the development of effector memory T helper type 1 (Th1) cells, while IL-10 deficiency promoted Th1 memory and blocking IL-10 signaling enhanced Th1 protective recall response against M.tb. IL-10 inhibited the binding of transcription factor CCAAT enhancer binding protein beta to S100a8/a9 promoter leading to S100A8/A9 reduction. S100A8/A9 heterodimer enhanced the IFN-γ production via receptor for advanced glycation end products signaling in CD4+ T cells. Our results demonstrate a hurdle to development of Th1 memory after BCG immunization and clarify the mechanism of the regulation of Th1 memory by IL-10 and S100A8/A9.

Non-destructive testing of steel wire ropes incorporating magnetic memory information

In order to avoid the influence of the interfering magnetic field, a wire rope magnetic memory detection platform under the excitation of a weak magnetic field is built and then the enhanced magnetic memory signal, infrared signal and visible light signal are fused to increase the recognition rate and reduce the identification error of the quantitative identification of broken wires, realising more effective defect identification and life assessment of wire ropes. The magnetic memory signal is denoised by applying intrinsic time-scale decomposition (ITD) and a wavelet algorithm to effectively remove noise such as the signal baseline and strand waves. The image fusion method based on curvelet transform is applied to realise pixel-level fusion of the defect images. The extracted fused image features are used as the input to the support vector machine optimised by the grey wolf optimiser (GWO-SVM) neural network to quantitatively identify wire rope defects. The results show that the image fusion method is better than the single detection method for broken wire identification.

Effects of sex and pro-inflammatory cytokines on context discrimination memory

In learning and memory tasks, immune overactivation is associated with impaired performance, while normal immune activation is associated with optimal performance. In one specific domain of memory, context discrimination memory, peripheral immune stimulation has been shown to impair performance on the context-object discrimination memory task in male rats. In order to evaluate potential sex differences in this task, as well as potential mechanisms for the memory impairment, we evaluated the ability of peripheral immune stimulation to impair task performance in both males and females. Next, we examined whether treatment with interleukin-1 receptor antagonist (IL-1ra), a receptor antagonist for the pro-inflammatory cytokine interleukin (IL)−1β, was able to rescue the memory deficit. We examined microglial morphology in the hippocampus and cytokine mRNA and protein expression in the hippocampus and the periphery. Male rats displayed memory impairment in response to LPS, and this impairment was not rescued by IL-1ra. Female rats did not have significant memory impairments and IL-1ra administration improved memory following inflammation. A subset of cytokines and chemokines were increased only in LPS-treated males. Inflammation alone did not alter microglia morphology, but IL-1ra did in certain sub-regions of the hippocampus. Together, these results indicate that sex differences exist in the ability of a peripheral immune stimulus to influence context discrimination memory and specific cytokine signals may be altered in impaired males. This study highlights the importance of sex differences in response to inflammatory challenges, especially related to memory impairments in context discrimination memory.

Neuronal and astrocytic CB1R signaling differentially modulates goal-directed behavior and working memory by distinct temporal mechanisms.

Several cognitive processes, including instrumental behavior and working memory, are controlled by endocannabinoids acting on cannabinoid receptor 1 (CB1R) in the brain through retrograde and presynaptic inhibition of GABA or glutamate release. However, the temporal mechanisms underlying the control of these cognitive processes by CB1Rs remain largely unknown. Here, we have developed a light-sensitive CB1R chimera (optoCB1R) by replacing the intracellular domains of bovine rhodopsin with those of human CB1R. We demonstrated that light stimulation of optoCB1R triggered canonical CB1R signaling by inhibiting cAMP (but not cGMP or IP1) signaling and activating the MAPK pathway in vitro or in vivo. Moreover, light stimulation of optoCB1R in corticostriatal glutamatergic neurons could temporally inhibit excitatory postsynaptic currents (EPSCs) at the level of seconds. Importantly, transient (3 s) and "time-locked", but not random, activation of optoCB1R signaling in corticostriatal neurons at the time of reward affected animal sensitivity to outcome devaluation and inhibited goal-directed behavior. However, prolonged (~30 min) but not transient (10 or 30 s) activation of astrocytic CB1R signaling in the hippocampus impaired working memory. Consequently, neuronal and astrocytic CB1R signaling differentially regulate working memory and goal-directed behavior through distinct temporal and cellular mechanisms. Ultimately, the pharmacological blockade of adenosine A2AR improved the neuronal and astrocytic CB1R-induced impairments in goal-directed behavior and working memory, possibly through modulation of EPSCs and c-Fos, respectively. Therefore, A2AR may represent a promising target for managing cognitive dysfunction resulting from the use of CB1R drugs.

The Potential Role of Integrin Signaling in Memory and Cognitive Impairment

Dementia currently has no cure and, due to the increased prevalence and associated economic and personal burden of this condition, current research efforts for the development of potential therapies have intensified. Recently, targeting integrins as a strategy to ameliorate dementia and other forms of cognitive impairment has begun to gain traction. Integrins are major bidirectional signaling receptors in mammalian cells, mediating various physiological processes such as cell-cell interaction and cell adhesion, and are also known to bind to the extracellular matrix. In particular, integrins play a critical role in the synaptic transmission of signals, hence their potential contribution to memory formation and significance in cognitive impairment. In this review, we describe the physiological roles that integrins play in the blood-brain barrier (BBB) and in the formation of memories. We also provide a clear overview of how integrins are implicated in BBB disruption following cerebral pathology. Given that vascular contributions to cognitive impairment and dementia and Alzheimer's' disease are prominent forms of dementia that involve BBB disruption, as well as chronic inflammation, we present current approaches shown to improve dementia-like conditions with integrins as a central focus. We conclude that integrins are vital in memory formation and that their disruption could lead to various forms of cognitive impairment. While further research to understand the relationships between integrins and memory is needed, we propose that the translational relevance of research efforts in this area could be improved through the use of appropriately aged, comorbid, male and female animals.

The gut-brain axis: Effect of electroacupuncture pretreatment on learning, memory, and JNK signaling in D-galactose-induced AD-like rats.

To examine the effect and potential mechanism of electroacupuncture (EA) pretreatment in spatial learning, memory, gut microbiota, and JNK signaling in D-galactose-induced AD-like rats. The AD-like rat model was generated by intraperitoneal injection of D-galactose. Morris water maze was used to determine spatial learning and memory ability, Real-time PCR to determine intestinal flora levels, ELISA to determine tryptophan (Trp) and 5-HT levels in the colon and hippocampal tissues, immunofluorescence to determine 5-HT levels in enterochromaffin cells (ECs), and immunoblotting to determine JNK signaling protein levels in hippocampal tissues. Electroacupuncture pretreatment significantly reduced escape latency and prolonged exploration time in the target quadrant, and significantly increased the relative DNA abundance of Lactobacillus and Bifidobacterium. Meanwhile, electroacupuncture pretreatment also reduced colonic 5-HT levels and increased hippocampal 5-HT levels. Moreover, electroacupuncture pretreatment significantly inhibited hippocampal JNK pathway-related protein expression, including 5-HT6R, JNK, p-JUNK, c-JUN, and p-c-Jun. And the combination of GV20 and ST36 was more effective than single acupoints. Electroacupuncture pretreatment improved the learning and memory ability of D-galactose-induced AD-like model rats, changed the gut microbiota composition, and the mechanism may be related to the gut-brain axis and the JNK signaling pathway. In addition, the combination of GV20 and ST36 could further enhance the efficacy.

Involuntary memory signals in the medial temporal lobe.

We highlight recent progress in neuroimaging and neuropsychological research on memory mechanisms in the medial temporal lobe that speaks to the involuntary nature of memory retrieval processes. We suggest that evidence form these studies supports Barzykowski and Moulin's proposal that memory signals involved in experiences of familiarity and déjà vu can be generated in the absence of retrieval intentionality.

A smartphone intervention that enhances real-world memory and promotes differentiation of hippocampal activity in older adults

The act of remembering an everyday experience influences how we interpret the world, how we think about the future, and how we perceive ourselves. It also enhances long-term retention of the recalled content, increasing the likelihood that it will be recalled again. Unfortunately, the ability to recollect event-specific details and reexperience the past tends to decline with age. This decline in recollection may reflect a corresponding decrease in the distinctiveness of hippocampal memory representations. Despite these well-established changes, there are few effective cognitive behavioral interventions that target real-world episodic memory. We addressed this gap by developing a smartphone-based application called HippoCamera that allows participants to record labeled videos of everyday events and subsequently replay, high-fidelity autobiographical memory cues. In two experiments, we found that older adults were able to easily integrate this noninvasive intervention into their daily lives. Using HippoCamera to repeatedly reactivate memories for real-world events improved episodic recollection and it evoked more positive autobiographical sentiment at the time of retrieval. In both experiments, these benefits were observed shortly after the intervention and again after a 3-mo delay. Moreover, more detailed recollection was associated with more differentiated memory signals in the hippocampus. Thus, using this smartphone application to systematically reactivate memories for recent real-world experiences can help to maintain a bridge between the present and past in older adults.

You cannot "count" how many items people remember in visual working memory: The importance of signal detection-based measures for understanding change detection performance.

Change detection tasks are commonly used to measure and understand the nature of visual working memory capacity. Across three experiments, we examine whether the nature of the memory signals used to perform change detection are continuous or all-or-none and consider the implications for proper measurement of performance. In Experiment 1, we find evidence from confidence reports that visual working memory is continuous in strength, with strong support for an equal variance signal detection model with no guesses or lapses. Experiments 2 and 3 test an implication of this, which is that K should confound response criteria and memory. We found K values increased by roughly 30% when criteria are shifted despite no change in the underlying memory signals. Overall, our data call into question a large body of work using threshold measures, like K, to analyze change detection data. This metric confounds response bias with memory performance and is inconsistent with the vast majority of visual working memory models, which propose variations in precision or strength are present in working memory. Instead, our data indicate an equal variance signal detection model (and thus, d')-without need for lapses or guesses-is sufficient to explain change detection performance. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Attentional capture mediates the emergence and suppression of intrusive memories.

Intrusive memories hijack consciousness and their control may lead to forgetting. However, the contribution of reflexive attention to qualifying a memory signal as interfering is unknown. We used machine learning to decode the brain's electrical activity and pinpoint the otherwise hidden emergence of intrusive memories reported during a memory suppression task. Importantly, the algorithm was trained on an independent attentional model of visual activity, mimicking either the abrupt and interfering appearance of visual scenes into conscious awareness or their deliberate exploration. Intrusion of memories into conscious awareness were decoded above chance. The decoding accuracy increased when the algorithm was trained using a model of reflexive attention. Conscious detection of intrusive activity decoded from the brain signal was central to the future silencing of suppressed memories and laterforgetting. Unwanted memories require the reflexive orienting of attention and access to consciousness to be suppressed effectively by inhibitory control.

Time-Dependent Electromigration Modeling for Workload-Aware Design-Space Exploration in STT-MRAM

Electromigration (EM) has been known as a reliability threatening factor for back-end-of-the-line interconnects. Spin-transfer torque magnetic RAM (STT-MRAM) is an emerging nonvolatile memory that has gained a lot of attention in recent years. However, relatively large operational current magnitude is a challenge for this technology, and hence, EM can be a potential reliability concern, even for the signal lines of this memory. A workload-aware EM modeling needs to capture time-dependent current density in the memory signal lines and to be able to predict the effect of the EM phenomenon on the interconnect for its entire lifetime. In this work, we present methods to effectively model the workload-dependent EM-induced meantime to failure (MTTF) in typical STT-MRAM arrays under a variety of realistic workloads. This allows performing the design-space exploration to co-optimize reliability and other design metrics.

Climatic fingerprint of spring discharge depletion in the southern Italian Apennines from 1601 to 2020 CE

Annual mean spring discharge (ASD) is an important water supply source, essential for ecological systems and societies dependent on groundwater resources. Influenced by both regional and local climate fluctuations, the inter-annual variability of ASD represents a climate memory signal, significantly affected when the drought pattern manifests itself in changing climatic regimes. Gaining a better historical perspective on ASD changes requires extended time-series of discharge data and relevant climate drivers. Here, using a parsimonious model, we present a continuous (modelled) time-series of annual ASD for the karst spring of Caposele, in the Cervialto Massif of southern Italy, which is hitherto the longest (1601–2020 CE) such time-series for the entire Mediterranean region. The model was designed to capture the importance of large-scale seasonal (spring, autumn and winter) precipitation (hydro-meteorological factor), and flood and drought indices (climatological factor), and to be consistent with a sample (1920–2020 CE) of actual data. We show a limited overall sensitivity of ASD to climate variability, with a mean of 4.21 m3 s−1 and a drop from ∼1759 CE. With a mean value of ∼3.60 m3 s−1 after ∼1987 CE, ASD has revealed a substantial descending trend—possibly a fingerprint of recent warming—with a depletion of regional water reservoirs. These results highlight the need to strengthen the capacity of groundwater resources in the face of changing, and possibly enhanced, drought patterns in the Mediterranean region.

Both APRIL and antibody-fragment-based CAR T cells for myeloma induce BCMA downmodulation by trogocytosis and internalization

BackgroundChimeric antigen receptor (CAR) T cell therapy targeting B cell maturation antigen (BCMA) on multiple myeloma (MM) produces fast but not long-lasting responses. Reasons for treatment failure are poorly understood....

Measuring memory is harder than you think: How to avoid problematic measurement practices in memory research.

We argue that critical areas of memory research rely on problematic measurement practices and provide concrete suggestions to improve the situation. In particular, we highlight the prevalence of memory studies that use tasks (like the "old/new" task: "have you seen this item before? yes/no") where quantifying performance is deeply dependent on counterfactual reasoning that depends on the (unknowable) distribution of underlying memory signals. As a result of this difficulty, different literatures in memory research (e.g., visual working memory, eyewitness identification, picture memory, etc.) have settled on a variety of fundamentally different metrics to get performance measures from such tasks (e.g., A', corrected hit rate, percent correct, d', diagnosticity ratios, K values, etc.), even though these metrics make different, contradictory assumptions about the distribution of latent memory signals, and even though all of their assumptions are frequently incorrect. We suggest that in order for the psychology and neuroscience of memory to become a more cumulative, theory-driven science, more attention must be given to measurement issues. We make a concrete suggestion: The default memory task for those simply interested in performance should change from old/new ("did you see this item'?") to two-alternative forced-choice ("which of these two items did you see?"). In situations where old/new variants are preferred (e.g., eyewitness identification; theoretical investigations of the nature of memory signals), receiver operating characteristic (ROC) analysis should be performed rather than a binary old/new task.

Evidence of Serial Dependence from Decoding of Visual Evoked Potentials.

It is well known that recent sensory experience influences perception, recently demonstrated by a phenomenon termed "serial dependence." However, its underlying neural mechanisms are poorly understood. We measured ERP responses to pairs of stimuli presented randomly to the left or right hemifield. Seventeen male and female adults judged whether the upper or lower half of the grating had higher spatial frequency, independent of the horizontal position of the grating. This design allowed us to trace the memory signal modulating task performance and also the implicit memory signal associated with hemispheric position. Using classification techniques, we decoded the position of the current and previous stimuli and the response from voltage scalp distributions of the current trial. Classification of previous responses reached full significance only 700 ms after presentation of the current stimulus, consistent with retrieval of an activity-silent memory trace. Cross-condition classification accuracy of past responses (trained on current responses) correlated with the strength of serial dependence effects of individual participants. Overall, our data provide evidence for a silent memory signal that can be decoded from the EEG potential, which interacts with the neural processing of the current stimulus. This silent memory signal could be the physiological substrate subserving at least one type of serial dependence.SIGNIFICANCE STATEMENT The neurophysiological underpinnings of how past perceptual experience affects current perception are poorly understood. Here, we show that recent experience is reactivated when a new stimulus is presented and that the strength of this reactivation correlates with serial biases in individual participants, suggesting that serial dependence is established on the basis of a silent memory signal.

Chloroplast proteomics reveals transgenerational cross-stress priming in Pinus radiata

Plants do have stress memory and chloroplast signaling has been revealed as crucial element to acquire and extend this memory into future generations, allowing plant adaptation to changing environments and providing novel tools in the field of crop improvement. Despite the process is known, how a plant is capable to transfer some aspects of its “life-long learning” to progeny, as well as the role of chloroplast proteome mediating transgenerational cross-stress priming effects, remain unknown. To fill this gap, this study examines the impact of the physiological status of Pinus radiata parentals over the capacity of their progeny to acclimate to their first stress period in a common garden experiment. Seedlings were originated in subpopulations with the same genetic background, but grown in two locations with contrasting environments (stressed vs non-stressed plants). Physiological measurements (fluorescence-based and biochemistry) and chloroplast proteomics were employed to study plant stress responses. Results demonstrated a differential seed priming. Those seedlings originated from stressed plants responded quicker and more efficiently than those originated from unstressed counterparts. Unprimed responses showed proteome remodeling driven by lipid peroxidation and photoinhibition, whereas primed subpopulation quickly faced stress rearranging secondary metabolism, replacing damaged lipids, reducing photooxidative damage, and promoting photorespiration and redox homeostasis in order to reduce lipoperoxidation and maintain photosynthesis. These results not only delve into cross-stress memory in long-lived species, but also suggest a new biotechnological potential for current seed orchards if adequate management is performed. • Parental growing conditions have transgenerational cross-stress priming effects. • Subpopulation originated from stressed plants responded quicker and more efficiently. • Primed responses were driven by photorespiration, redox, and secondary metabolism. • Knowledge acquired suggests a new biotechnological potential for seed orchards.

An adaptive perspective on visual working memory distortions.

When holding multiple items in visual working memory, representations of individual items are often attracted to, or repelled from, each other. While this is empirically well-established, existing frameworks do not account for both types of distortions, which appear to be in opposition. Here, we demonstrate that both types of memory distortion may confer functional benefits under different circumstances. When there are many items to remember and subjects are near their capacity to accurately remember each item individually, memories for each item become more similar (attraction). However, when remembering smaller sets of highly similar but discernible items, memory for each item becomes more distinct (repulsion), possibly to support better discrimination. Importantly, this repulsion grows stronger with longer delays, suggesting that it dynamically evolves in memory and is not just a differentiation process that occurs during encoding. Furthermore, both attraction and repulsion occur even in tasks designed to mitigate response bias concerns, suggesting they are genuine changes in memory representations. Together, these results are in line with the theory that attraction biases act to stabilize memory signals by capitalizing on information about an entire group of items, whereas repulsion biases reflect a tradeoff between maintaining accurate but distinct representations. Both biases suggest that human memory systems may sacrifice veridical representations in favor of representations that better support specific behavioral goals. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Propagation Characteristics of Magnetic Tomography Method Detection Signals of Oil and Gas Pipelines Based on Boundary Conditions.

The magnetic tomography method (MTM) is a non-contact external inspection method for detecting metal magnetic memory signals. It has great potential for application in long-distance oil pipeline and subsea pipeline inspection. However, the spatial distribution characteristics and propagation laws of magnetic signals are not yet clear, which makes the MTM passive detection. In this study, a three-dimensional mathematical model of the magnetic field distribution of the stress concentration zone outside the pipe was established based on the boundary conditions. For the two cases in which the stress concentration zone was located at the top and bottom of the inner wall of the pipe, the model was solved by finite element analysis. The variation law of the magnetic signal outside the pipe was analyzed, and experiments were designed to verify the model. The results show that the shape of the magnetic memory signal remained unchanged after passing through the pipe wall. As the magnetic permeability of the pipe medium is much larger than that of air, the magnetic memory signal is significantly attenuated after penetrating the pipe wall. As the detection height increases, the magnetic induction outside the tube decays exponentially. The results also prove that the magnetic tomography method can detect the stress concentration zone at any position of the pipeline, and the detection accuracy is higher when it is located at the top of the pipeline.

Magnetic-Acoustic Feature Extraction and Damage Fusion Evaluation of 45 Steel Specimens during Fatigue Process for Remanufacturing

To clarify the changes of the magnetic-acoustic features of 45 steel specimens during fatigue damage, an experimental platform was built to carry out magnetic memory and acoustic emission detection. The magnetic memory and acoustic emission signals of specimens in different damage states were collected, and the multi-scale entropy characteristics of magnetic memory signals, as well as the wavelet packet energy spectrum and singularity index characteristics of acoustic emission signals, were further extracted. A magnetic-acoustic feature fusion and damage assessment model was constructed by using Naive Bayes method. Results show that the average value of multi-scale entropy of normal magnetic field intensity Hp (y) increases gradually with the increase of fatigue cycles, and the average value of multi-scale entropy of magnetic field intensity gradient K gradually decreases. The cumulative ringing count and energy spectrum (proportion of frequency band 1) of acoustic emission signals decrease with the increase of fatigue cycles, while the amplitude singularity index gradually increases. The established model has high evaluation accuracy, and the conclusions of this paper can provide basic methods and data support for fatigue damage evaluation of remanufactured components.