Classical Memory Research Articles

Do qubits dream of entangled sheep? Quantum measurement without classical output

Quantum mechanics is usually formulated with an implicit assumption that agents who can observe and interact with the world are external to it and have a classical memory. However, there is no accepted way to define the quantum–classical cut and no a priori reason to rule out fully quantum agents with coherent quantum memories. In this work, we introduce an entirely quantum notion of measurement, called a sensation, to account for quantum agents that experience the world through quantum sensors. Sensations eschew probabilities and instead describe a deterministic flow of quantum information. We quantify the information gain and disturbance of a sensation using concepts from quantum information theory and find that sensations always disturb at least as much as they inform. Viewing measurements as sensations could lead to a new understanding of quantum theory in general and to new results in the context of quantum networks.

Longitudinal assessment of humoral immune response against SARS-CoV-2 in solid cancer patients: Implications for vaccination strategies

Abstract In the face of evolving SARS-CoV-2 variants, immunocompromised patients, particularly those with solid cancers, pose unique challenges in vaccine responsiveness. We investigated the humoral immune responses in solid cancer patients (n=64) undergoing anti-cancer treatments, comparing them to healthcare workers (n=23). Over 12 months, we tracked SARS-CoV-2 spike (S) and receptor binding domain (RBD) specific antibodies, memory B cells, and circulating follicular helper T cells (cTfh) post two to five doses of monovalent or bivalent vaccinations and after Omicron variant breakthrough infections (BTI). After the third vaccination, solid cancer patients exhibited antibody levels against wild-type and variants similar to healthy controls. Notably, post-BTI, these patients showed heightened and sustained antibody responses, indicating the efficacy of hybrid immunity. S-specific memory B cells initially mirrored healthy individuals after the third dose but declined faster. The fourth dose had minimal impact, while the fifth significantly boosted classical memory B cells. Post-BTI, durable S-specific memory B cells increased, irrespective of prior vaccination doses. Our findings highlight the resilient and prolonged humoral immunity induced by repeated vaccinations and BTIs in solid cancer patients, offering critical insights for tailored vaccination strategies in immunocompromised populations.

In-depth immune profiling of peripheral blood mononuclear cells in patients with pancreatic ductal adenocarcinoma reveals discriminative immune subpopulations.

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis with a 5-year survival of less than 10%. More knowledge of the immune response developed in patients with PDAC is pivotal to develop better combination immune therapies to improve clinical outcome. In this study, we used mass cytometry time-of-flight to undertake an in-depth characterization of PBMCs from patients with PDAC and examine the differences with healthy controls and patients with benign diseases of the biliary system or pancreas. Peripheral blood mononuclear cells from patients with PDAC or benign disease are characterized by the increase of pro-inflammatory cells, as CD86+ classical monocytes and memory T cells expressing CCR6+ and CXCR3+, associated with T helper 1 (Th1) and Th17 immune responses, respectively. However, PBMCs from patients with PDAC present also an increase of CD39+ regulatory T cells and CCR4+CCR6-CXCR3- memory T cells, suggesting Th2 and regulatory responses. Concluding, our results show PDAC develops a multifaceted immunity, where a proinflammatory component is accompanied by regulatory responses, which could inhibit potential antitumor mechanisms.

Osteomyelitis is associated with increased anti-inflammatory response and immune exhaustion.

Osteomyelitis (OMS) is a bone infection causing bone pain and severe complications. A balanced immune response is critical to eradicate infection without harming the host, yet pathogens manipulate immunity to establish a chronic infection. Understanding OMS-driven inflammation is essential for disease management, but comprehensive data on immune profiles and immune cell activation during OMS are lacking. Using high-dimensional flow cytometry, we investigated the detailed innate and adaptive systemic immune cell populations in OMS and age- and sex-matched controls. Our study revealed that OMS is associated with increased levels of immune regulatory cells, namely T regulatory cells, B regulatory cells, and T follicular regulatory cells. In addition, the expression of immune activation markers HLA-DR and CD86 was decreased in OMS, while the expression of immune exhaustion markers TIM-3, PD-1, PD-L1, and VISTA was increased. Members of the T follicular helper (Tfh) cell family as well as classical and typical memory B cells were significantly increased in OMS individuals. We also found a strong correlation between memory B cells and Tfh cells. We conclude that OMS skews the host immune system towards the immunomodulatory arm and that the Tfh memory B cell axis is evident in OMS. Therefore, immune-directed therapies may be a promising alternative for eradication and recurrence of infection in OMS, particularly in individuals and areas where antibiotic resistance is a major concern.

Protecting information via probabilistic cellular automata.

Probabilistic cellular automata describe the dynamics of classical spin models, which, for sufficiently small temperature T, can serve as classical memory capable of storing information even in the presence of nonzero external magnetic field h. In this article, we study a recently introduced probabilistic cellular automaton, the sweep rule, and map out a region of two coexisting stable phases in the (T,h) plane. We also find that the sweep rule belongs to the weak two-dimensional Ising universality class. Our work is a step towards understanding how simple geometrically local error-correction strategies can protect information encoded into complex noisy systems, such as topological quantum error-correcting codes.

Visual perception of highly memorable images is mediated by a distributed network of ventral visual regions that enable a late memorability response.

Behavioral and neuroscience studies in humans and primates have shown that memorability is an intrinsic property of an image that predicts its strength of encoding into and retrieval from memory. While previous work has independently probed when or where this memorability effect may occur in the human brain, a description of its spatiotemporal dynamics is missing. Here, we used representational similarity analysis (RSA) to combine functional magnetic resonance imaging (fMRI) with source-estimated magnetoencephalography (MEG) to simultaneously measure when and where the human cortex is sensitive to differences in image memorability. Results reveal that visual perception of High Memorable images, compared to Low Memorable images, recruits a set of regions of interest (ROIs) distributed throughout the ventral visual cortex: a late memorability response (from around 300 ms) in early visual cortex (EVC), inferior temporal cortex, lateral occipital cortex, fusiform gyrus, and banks of the superior temporal sulcus. Image memorability magnitude results are represented after high-level feature processing in visual regions and reflected in classical memory regions in the medial temporal lobe (MTL). Our results present, to our knowledge, the first unified spatiotemporal account of visual memorability effect across the human cortex, further supporting the levels-of-processing theory of perception and memory.

The effects of mnemonic variability and spacing on memory over multiple timescales

The memory benefit that arises from distributing learning over time rather than in consecutive sessions is one of the most robust effects in cognitive psychology. While prior work has mainly focused on repeated exposures to the same information, in the real world, mnemonic content is dynamic, with some pieces of information staying stable while others vary. Thus, open questions remain about the efficacy of the spacing effect in the face of variability in the mnemonic content. Here, in two experiments, we investigated the contributions of mnemonic variability and the timescale of spacing intervals, ranging from seconds to days, to long-term memory. For item memory, both mnemonic variability and spacing intervals were beneficial for memory; however, mnemonic variability was greater at shorter spacing intervals. In contrast, for associative memory, repetition rather than mnemonic variability was beneficial for memory, and spacing benefits only emerged in the absence of mnemonic variability. These results highlight a critical role for mnemonic variability and the timescale of spacing intervals in the spacing effect, bringing this classic memory paradigm into more ecologically valid contexts.

Marginal Zone B Cells Are Necessary for the Formation of Anti-donor IgG After Allogeneic Sensitization.

The formation of anti-major histocompatibility complex (MHC) antibodies is a significant barrier for many patients awaiting organ transplantation. Patients with preformed anti-MHC antibodies have limited options for suitable donors, and the formation of donor-specific anti-MHC antibodies after transplantation is a harbinger of graft rejection. Despite the recognized importance of anti-MHC antibodies, the mechanisms responsible for the differentiation of B cells after exposure to allogeneic antigens are poorly understood. To evaluate the differentiation of B cells in response to allogeneic antigen, we used a model of H-2 b C57Bl/6 sensitization with H-2 d antigen. We used a class I MHC tetramer-based approach to identify allogeneic B cells and flow cytometric crossmatch to identify allogeneic IgM and IgG. We found that although the formation of anti-H-2 d IgG was robust, few class-switched B cells and germinal center B cells were formed. Antigen-specific B cells did not express classical memory B-cell markers after sensitization but had an IgM + CD21 + marginal zone B-cell phenotype. The frequency of marginal zone B cells increased after sensitization. Depletion of marginal zone B cells before sensitization or skin grafting resulted in a significant diminution of anti-H-2 d IgG and fewer germinal center B cells. Adoptive transfer experiments revealed that marginal zone B cells more efficiently differentiated into germinal center B cells and anti-donor IgG-producing cells than follicular B cells. These results demonstrate an important role for marginal zone B cells as a reservoir of alloreactive B cells that are activated by allogeneic antigens.

Memory Effects in the Magnetoresistance of Two-Component Electron Systems

The theory of the magnetotransport in a two-component electron system with rare macroscopic defects has been developed. In such a system, the classical memory effects in the scattering of electrons by defects and a slow transfer of electrons between the components of the liquid occurring due to the electron–electron scattering play a decisive role. It has been shown that the flow regime depends on the ratio of the sample width to the characteristic internal length, which is determined by the rate of electron transfer between the components. In samples wider than the internal length, the flow of the two-component liquid as a whole is formed within the bulk of the sample and is described by the corresponding Drude formulas taking into account memory effects. In this case, the magnetoresistance is positive at low magnetic fields and negative at high fields. In samples narrower than the characteristic length, the transfers involving a change in the type of electrons do not provide enough time to form a unified liquid. As a result, the flows of different components are independent and described by their own conductivities, taking into account the memory effects, while the magnetoresistance is strictly negative.

Collaborative Memory: What Happens With Remote Communication?

Abstract: Information and communication technologies have profoundly changed the way people daily remember and discuss opinions and information while interacting and collaborating with common everyday activities such as working, teaching, and studying. Indeed, the rise of Internet connectivity and rapidly expanding social media platforms raises new questions about how false and true memories spread across social connections and is critical to further understanding everyday human memory functioning. Here, we adopted a classic collaborative memory paradigm and investigated memory performance across two different experimental conditions: in-person and computer-mediated communication via video calls on Teams to evaluate the effects of remote collaboration on memory recall. Results showed that individuals who collaborated in presence and individuals who collaborated via computer had comparable memory performance when communication was enriched with verbal and nonverbal cues.

Cellular and Epigenetic Aspects of Trained Immunity and Prospects for Creation of Universal Vaccines in the Face of Increasingly Frequent Pandemics

The inevitability of pandemics creates an urgent requirement for emergency action to develop effective technologies to reduce harm to the human population in the period between the onset of an epidemic and the development and production of a vaccine. In this review we discuss the possibility of engineering universal vaccines. Such vaccines would exploit the nonspecific potential of innate immunity, would allow the population to be vaccinated when an unidentified pathogen appears, and would reduce disease severity until pathogen-specific vaccines become available. There are strong evidences that bacterial or viral vaccines such as BCG, measles and polio have heterologous protective effects against unrelated pathogens. This is attributed to the innate immune system’s ability to maintain the memory of past infections and use it to develop immune defenses against new ones. This effect has been called “trained” immunity. The use of trained immunity may also represent an important new approach to improving existing vaccines or to developing new vaccines that combine the induction of classical adaptive immune memory and innate immune memory. Such approaches can be boosted by genetic technology and prove extremely useful against future pandemics.

Randomized, double-blind, placebo-controlled trial of rapamycin in amyotrophic lateral sclerosis

In preclinical studies rapamycin was found to target neuroinflammation, by expanding regulatory T cells, and affecting autophagy, two pillars of amyotrophic lateral sclerosis (ALS) pathogenesis. Herein we report a multicenter, randomized, double-blind trial, in 63 ALS patients who were randomly assigned in a 1:1:1 ratio to receive rapamycin 2 mg/m2/day,1 mg/m2/day or placebo (EUDRACT 2016-002399-28; NCT03359538). The primary outcome, the number of patients exhibiting an increase >30% in regulatory T cells from baseline to treatment end, was not attained. Secondary outcomes were changes from baseline of T, B, NK cell subpopulations, inflammasome mRNA expression and activation status, S6-ribosomal protein phosphorylation, neurofilaments; clinical outcome measures of disease progression; survival; safety and quality of life. Of the secondary outcomes, rapamycin decreased mRNA relative expression of the pro-inflammatory cytokine IL-18, reduced plasmatic IL-18 protein, and increased the percentage of classical monocytes and memory switched B cells, although no corrections were applied for multiple tests. In conclusion, we show that rapamycin treatment is well tolerated and provides reassuring safety findings in ALS patients, but further trials are necessary to understand the biological and clinical effects of this drug in ALS.

Helitronics as a potential building block for classical and unconventional computing

Magnetic textures are promising candidates for unconventional computing due to their non-linear dynamics. We propose to investigate the rich variety of seemingly trivial lamellar magnetic phases, e.g. helical, spiral, stripy phase, or other one-dimensional soliton lattices. These are the natural stray field-free ground states of almost every magnet. The order parameters of these phases may be of potential interest for both classical and unconventional computing, which we refer to as helitronics. For the particular case of a chiral magnet and its helical phase, we use micromagnetic simulations to demonstrate the working principles of all-electrical (i) classical binary memory cells and (ii) memristors and artificial synapses, based on the orientation of the helical stripes.

Multiple silicon dangling-bond charge qubits for quantum computing: a Hilbert-space analysis of the Hamiltonian

Silicon-based dangling-bond charge qubit is one of the auspicious models for universal fault-tolerant solid-state quantum computing. In universal quantum computing, it is crucial to evaluate and characterize the computational Hilbert space and reduce the complexity and size of the computational space. Here, we recognize this problem to understand the complexity and characteristics of the Hilbert space in our dangling-bond qubit model. The size of the desired Hilbert space can prominently be reduced by considering assumptions regarding the qubit loss. Moreover, the dimension of the desired subsets in the space shrinks by a factor of two due to the spin preservation property. Finally, the required classical memory for storage of the qubit information, Hamiltonian and Hilbert space is analysed when the number of qubits grows.

Rossler’s system using piecewise derivative

This article deals with a piecewise system named piecewise Rossler’s system which exhibits a concept of piecewise derivatives based on Classical-power-law randomness, Classical Mittag-Leffler-law-randomness, and Classical fading memory randomness fractional operators. To examine the crossover and chaos patterns for Rossler’s system, we have revisited and modified Rossler’s system using the concept of a piecewise system. This paper focuses also on growing a forecasting piecewise system to establish states in chaotic aspects. The existence and uniqueness are obtained for piecewise Rossler’s system with the Caputo derivative. The numerical solutions are based on Newton interpolation. Numerical solutions have been developed to approximate these piecewise derivatives. The obtained results show real-world behaviors of Rossler’s systems with piecewise patterns at various values of order α.

SARS-CoV-2 RBD-specific atypical memory B cells exhibit effector memory-like features in multi-dose mRNA vaccination

Abstract Memory B cell is a heterogenous population and such heterogeneity is a focus of active investigation. How distinct subsets of memory B cells respond to repeated novel antigen challenges such as SARS-CoV-2 in human remains a subject of vigorous research. We employed fluorochrome-conjugated streptavidin tetramers bound with RBD of wild-type and omicron variant (B.1.1.529), respectively, to sort RBD-specific B cells and performed CITE-seq to investigate detailed dynamics of transcriptomes, surface phenotyes and clonality in healthy mRNA vaccination cohort. PBMC samples of 8 BNT162b2 vaccine recipients from 7 consecutive timepoints, before and after each dose of 3-times vaccination, were analyzed. We found pulsating, yet with increasing trend, frequency of atypical memory B cells among tetramer-binding B cells after each dose of vaccine. SCENIC analysis of tetramer-binding memory B cells to find subset-specific regulatory gene networks revealed atypical memory B cells have distinct regulons of genes related to activation such as receptor clustering, signaling and calcium-dependent activation compared with classical memory B cells and found only one shared clone between atypical and classical tetramer-binding memory B cells, suggesting infrequent interconversion between the two subsets. Furthermore, in-vitro polyclonal stimulation of atypical memory B cells showed higher frequency of antibody-secreting cells (ASC) and pre-plasmablasts in flow cytometry and wild-type RBD-specific ASCs in IgG ELISPOT assay, compared with classical memory B cells. These findings highlight effector memory-like features of atypical memory B cells in viral antigen challenge and a potential target of future vaccine design.

Exploring the Role of T VMCells in Age-Related CD8 +T Cell Dysfunction through ATAC-seq and RNA-seq Analysis

Abstract Virtual memory T (T VM) cells are a unique subset of CD8 +T cells that have both classical memory and innate-like immune function. Unlike other CD8 +T cell subsets, T VMcells are highly dependent on cytokines for their homeostasis and are selectively depleted in mice lacking IL-15. In aged mice and humans, T VMcells acquire T cell receptor-associated defects, which may contribute to the decline in overall CD8 +T cell function seen with aging. T VMcells make up a large proportion of the naive CD8 +T cell pool in aged individuals, making them an ideal target for age-specific therapeutic interventions. In this study, we performed ATAC-seq and RNA-seq analysis on young and aged mouse CD8 +T cell subsets and identified several key signatures associated with age-related dysfunction specifically in T VMcells. These signatures reveal a bifurcation in the aging process whereby memory-phenotype CD8 +T cells are affected differently by the aging environment. The aged-specific T VMsignature is distinct from that of conventional memory CD8 +T cells and results in the upregulation of immunomodulatory molecules such as Fcgr2b, which encodes the low-affinity inhibitory Fcγ receptor. Expression of FcγRIIB on CD8 +T cells has been shown to play a role in suppressing anti-tumor immunity and mitigating graft-versus-host disease. We show that a subset of aged T VMcells upregulate FcγRIIB independently of antigen exposure and are prone to apoptosis in vitro. Blockade of FcγRIIB has been shown to augment CD8 +T cell responses in vivo, making it a potential therapeutic target for restoring function in aged T VMcells. These findings provide insight into the mechanisms of age-related immune dysfunction and potential strategies for targeting T VMcells in the elderly. Supported by grants from NHMRC/ARC

Nonverbal memory tests revisited: Neuroanatomical correlates and differential influence of biasing cognitive functions

The detection of right temporal lobe dysfunction with nonverbal memory tests has remained difficult in the past. Reasons for this might be the potential influence of other biasing cognitive functions such as executive functions or the verbalisability of nonverbal material. The aim of this study was to investigate three classic nonverbal memory tests by identifying their neuroanatomical correlates with lesion-symptom mapping (LSM) and by probing their independence from verbal encoding abilities and executive functions.In a cohort of 119 patients with first-time cerebrovascular accident, memory performance was assessed in the Nonverbal Learning and Memory Test for Routes (NLMTR), the Rey Complex Figure Test (RCFT), and the Visual Design Learning Test (VDLT). Calculating multivariate LSM, we identified crucial brain structures for these three nonverbal memory tests. Behavioural analyses were performed to assess the impact of executive functions and verbal encoding abilities with regression analyses and likelihood-ratio tests.LSM revealed for the RCFT mainly right-hemispheric frontal, insular, subcortical, and white matter structures and for the NLMTR right-hemispheric temporal (hippocampus), insular, subcortical, and white matter structures. The VDLT did not reach significance in LSM analyses. Behavioural results showed that amongst the three nonverbal memory tests the impact of executive functions was most pronounced for RCFT, and the impact of verbal encoding abilities was most important in VDLT. Likelihood-ratio tests confirmed that only for NLMTR did the goodness of fit not significantly improve by adding executive functions or verbal encoding abilities.These results suggest that amongst the three nonverbal memory tests the NLMTR, as a spatial navigation test, could serve as the most suitable marker of right-hemispheric temporal lobe functioning, with the right hippocampus being involved only in this test. In addition, the behavioural results propose that only NLMTR seems mostly unaffected by executive functions and verbal encoding abilities.

Investigation of the frequencies of various B cell populations in non-responder healthcare workers in comparison with responders to hepatitis B virus vaccination.

Hepatitis B is a major global health problem. More than 90% of hepatitis B-vaccinated immunocompetent adults become fully immune. The main purpose of vaccination is immunization. Whether non-responders have a lower percentage of total or antigen-specific memory B cells in comparison with responders is still controversial. We aimed to assess and compare the frequency of various B cell subpopulations in non-responders and responders. Fourteen responders and 14 non-responders of hospital healthcare workers were enrolled in this study. We used flow cytometry to evaluate various CD19+ B cell subpopulations using fluorescent-labeled antibodies against CD19, CD10, CD21, CD27 and IgM and ELISA to evaluate total anti-HBs antibodies. We found no significant differences in the frequency of various B cell subpopulations between the non-responder and responder groups. Furthermore, the frequency of the isotype-switched memory B cell population was significantly higher in the atypical memory B cell subset compared with the classical memory B cell subset in the responder and total groups (p=0.010 and 0.003, respectively). Responders and non-responders to HBsAg vaccine had comparable memory B cell populations. Whether anti-HBs Ab production has a correlation with the level of class switching in B lymphocytes in healthy vaccinated individuals needs further investigation.

An adaptive EWMA control chart based on Hampel function to monitor the process location parameter

AbstractThe classical memory Exponential Weighted Moving Average (EWMA) and Cumulative Sum (CUSUM) control charts (CCs) are important to detect small‐to‐moderate sizes of shift in the process location and/or dispersion parameters. To make the memory control chart (CC) more efficient for broad range of shift, the score functions in particular Huber and Bi‐square functions are incorporated in the classical memory CCs. These score functions help to formulate the parameters of memory CCs and are called Adaptive EWMA (AEWMA) and Adaptive CUSUM (ACUSUM). The AEWMA and ACUSUM are capable to handle various sizes (i.e., small, moderate, and large) of shift. The aim of this study is to utilize Hampel function as the alternative of the mentioned score functions, and propose a new AEWMA CC, symbolized as AEWMAHample. To develop the proposed AEWMAHampleCC, the standard EWMA statistic and Hampel function are incorporated in the classical EWMA CC structure. The proposed AEWMAHampleCC is also efficient to handle certain sizes of shift in the process location parameter. Performance evaluation procedures, like average run length is considered for a particular shift. Similarly, the performance comparison index, relative average run length, and extra quadratic loss function are estimated over a range of shift. All these performance measures are calculated from run length (RL) characteristic of the proposed control chart. An algorithm in MATLAB is developed based on Monte Carlo simulation procedure to generate the RLs. Some existing control charts including EWMA, CUSUM, MEC, MCE, , , IACCUSUM, , and are taken for comparison reason. For specific sizes of shift, the proposed AEWMAHampleCC reveals the superiority. Besides, to address the practical significance for practitioners and quality engineers, the real‐life and simulated data examples are considered.