Memory Awareness Research Articles

Awareness of episodic memory and meta-cognitive profiles: associations with cerebrospinal fluid biomarkers at the preclinical stage of the Alzheimer's continuum.

The lack of cognitive awareness, anosognosia, is a clinical deficit in Alzheimer's disease (AD) dementia. However, an increased awareness of cognitive function, hypernosognosia, may serve as a marker in the preclinical stage. Subjective cognitive decline (SCD) might correspond to the initial symptom in the dynamic trajectory of awareness, but SCD might be absent along with low awareness of actual cognitive performance in the preclinical stage. We hypothesized that distinct meta-cognitive profiles, both hypernosognosia and anosognosia, might be identified in preclinical-AD. This research evaluated the association between cerebrospinal fluid (CSF) AD biomarkers and the awareness of episodic memory, further exploring dyadic (participant-partner) SCD reports, in the preclinical Alzheimer's continuum. We analyzed 314 cognitively unimpaired (CU) middle-aged individuals (mean age: 60, SD: 4) from the ALFA+ cohort study. Episodic memory was evaluated with the delayed recall from the Memory Binding Test (MBT). Awareness of episodic memory, meta-memory, was defined as the normalized discrepancy between objective and subjective performance. SCD was defined using self-report, and dyadic SCD profiles incorporated the study partner's report using parallel SCD-Questionnaires. The relationship between CSF Aβ42/40 and CSF p-tau181 with meta-memory was evaluated with multivariable regression models. The role of SCD and the dyadic contingency was explored with the corresponding stratified analysis. CSF Aβ42/40 was non-linearly associated with meta-memory, showing an increased awareness up to Aβ-positivity and a decreased awareness beyond this threshold. In the non-SCD subset, the non-linear association between CSF Aβ42/40 and meta-memory persisted. In the SCD subset, higher Aβ-pathology was linearly associated with increased awareness. Individuals presenting only study partner's SCD, defined as unaware decliners, exhibited higher levels of CSF p-tau181 correlated with lower meta-memory performance. These results suggested that distinct meta-cognitive profiles can be identified in preclinical-AD. While most individuals might experience an increased awareness associated with the entrance in the AD continuum, hypernosognosia, some might be already losing insight and stepping into the anosognosic trajectory. This research reinforced that an early anosognosic profile, although at increased risk of AD-related decline, might be currently overlooked considering actual diagnostic criteria, and therefore its medical attention delayed.

Adding topology and memory awareness in data aggregation algorithms

With the growing gap between computing power and the ability of large-scale systems to ingest data, I/O is becoming the bottleneck for many scientific applications. Improving read and write performance thus becomes decisive, and requires consideration of the complexity of architectures. In this paper, we introduce TAPIOCA, an architecture-aware data aggregation library. TAPIOCA offers an optimized implementation of the two-phase I/O scheme for collective I/O operations, taking advantage of the many levels of memory and storage that populate modern HPC systems, and leveraging network topology. We show that TAPIOCA can significantly improve the I/O bandwidth of synthetic benchmarks and I/O kernels of scientific applications running on leading supercomputers. For example, on HACC-IO, a cosmology code, TAPIOCA improves data writing by a factor of 13 on nearly a third of the target supercomputer.

Metacognitive beliefs of efficacy about daily life situations and use of cognitive strategies in amnestic mild cognitive impairment: a cross-sectional study.

Metacognition, the ability to monitor and regulate cognitive processes, is essential for individuals with Mild Cognitive Impairment (MCI) to accurately identify their deficits and effectively manage them. However, previous studies primarily focused on memory awareness in MCI, neglecting other domains affected in daily life. This study aimed to investigate how individuals with MCI perceive their abilities to handle various cognitively challenging situations representing real-life scenarios and their use of compensatory strategies. Thus 100 participants were recruited, including 50 with amnestic MCI with multiple deficits (aMCI) and 50 cognitively healthy controls (HC) matched in age and education. Participants completed three metacognitive scales assessing self-perceived efficacy in everyday life scenarios and one scale evaluating use of cognitive strategies. Results indicated that aMCI participants reported significantly lower self-efficacy in memory and divided-shifted attention scenarios compared to HC. Surprisingly, no significant group differences were found in the self-reports about the use of cognitive strategies. This suggests a potential gap in understanding or applying effective strategies for compensating cognitive deficits. These findings emphasize the importance of cognitive training programs targeting metacognitive knowledge enhancement and practical use of cognitive strategies that could enhance the quality of life for individuals with MCI.

European Heritage Label-based Education as an Essential Part of Memory Education – The Polish Case

The purpose of this article is to show how the EHL is used for the interpretation, awareness, and transmission of heritage and memory. As part of the EU European Heritage Label (EHL) program, Polish institutions received six distinctions in the years 2014-2019, which places Poland high in the ranking of the awarded Brands in Europe. Polish institutions are obligated to spreading knowledge about the cultural heritage of Europe. On the one hand, EHL’s task is to raise awareness and transmit common values, elements of European history, and heritage, which can be interpreted as promoting “uni memory.” On the other hand, EHL aims to deepen intercultural dialogue and synergy, recognizing the values of diversity, which can be understood as promoting the idea of plural memory. The EHL organizers in Poland are obliged (by the provisions of the EU Program) to conduct a European narrative, but in practice, they sometimes remain at the stage of restoring and refreshing the memory of the site, organizing local memory, and revising the regional policy due to “dormant memory” during the communist period.

Cerebral systems underlying anosognosia for memory loss in aging and Alzheimer’s disease

AbstractBackgroundLoss of awareness of cognitive decline (a.k.a. anosognosia) is a common symptom of Alzheimer’s disease (AD) dementia and has also been observed in its predementia stages. Anosognosia is thought to be related not only to functional changes in individual brain regions, but also to a disturbance in functional connectivity (FC) between or within networks. This study aimed to investigate how memory awareness relates to resting‐state fMRI segregation (within‐network connectivity) and integration (between‐network connectivity) maps across the AD spectrum.MethodWe included 66 older adults divided in two groups: cognitively normal (CN, n = 49), and symptomatic (mild cognitive impairment or mild AD; n = 17). Memory awareness was measured as the discrepancy between the participant’s and study partner’s scores on the Cognitive Function Instrument. Positive values indicated heightened awareness and negative values indicated unawareness. We assessed whole‐brain connectivity with resting‐state fMRI and computed voxel‐level maps of segregation and integration. General linear models were used to relate the integration or segregation of each voxel to memory awareness (in the total sample and in the two groups separately), adjusted for age, sex, and education. Multiple comparison correction was performed using cluster‐wise Monte Carlo simulations.ResultDemographics are presented in Table 1. Segregation maps showed that lower awareness was associated with increased connectivity within the frontoparietal network (FPN) and with decreased connectivity within the medial visual, default mode (DMN), and sensory‐motor networks (Figure 1A(i); Table 2A(i)). The relationship with the FPN persisted in the CN and symptomatic groups separately, and an additional negative association between awareness and FC in the salience network was found in the CN group (Figure 1B‐C(i); Table 2B‐C(i)). In integration maps, lower awareness was associated with increased between‐network connectivity of the dorsal attention and DMN, and decreased connectivity of the salience and sensory‐motor networks (Figure 1A(ii); Table 2A(ii)). In the CN group, the sensory‐motor relationship persisted, while the DMN relationship reversed (Figure 1B‐C(ii); Table 2B‐C(ii)).ConclusionAnosognosia is characterized by reduced FC patterns featuring disconnection between self‐referential networks (DMN and salience) to other networks and hyperconnectivity within the FPN. Future studies should investigate the pathological underpinnings for these functional changes.

A Note on the Validity of Metaphor Universality

Metaphor universality has been a topic of long debate among interested researchers. A byproduct of claiming the universality of metaphors is admitting a common human cognition. This cognition is based on different factors external to the cognition itself. In the present study, metaphors from Arabic tweets were analyzed and compared to metaphors in English found in published research. Based on this comparison, it was concluded that metaphors are universal and culturally specific at two different levels. On one level, the shared human anatomy poses universality, and on the other level, factors working against such universality affect the cultural specificity of metaphors. Kövecses (2010b) proposes a list of factors including awareness of context, differential memory, differential concerns and interests, differential cognitive preference and styles, and creativity. Considering languages other than Arabic and English in the comparison can be a promising future research.

Do Psychedelics Facilitate Emergence of Unconscious Psychological Processes?

Psychedelic substances have a long history of use in traditional healing and religious ceremonies worldwide and are increasingly being investigated for their possible therapeutic usage. However, there is still a lack of consensus regarding how best to characterize the psychological effects of psychedelics and how they bring about the positive therapeutic outcomes observed in clinical studies. The aim of this article is to review available evidence from quantitative and qualitative studies on psychedelic-assisted therapy, as well as neurobiological studies, in relation to the hypothesis that psychedelics facilitate the emergence of emotionally charged unconscious material, originally proposed by pioneering psychedelics researcher Stanislav Grof. The reviewed process studies of therapeutic mechanisms in psychedelic-assisted therapy and qualitative studies of treatment participants clearly indicate that the psychedelic experience is associated with the subjective experience of having increased access to and awareness of emotions, memories, and perceptions that are normally avoided or outside of conscious awareness. Brain-imaging studies point to several different neurobiological effects of psychedelics that might be related to these subjective psychological experiences. Available evidence also indicates that this process might constitute an important therapeutic mechanism in psychedelic-assisted therapy, worthy of further investigation.

Scalable Spatial Memory for Scene Rendering and Navigation

Neural scene representation and rendering methods have shown promise in learning the implicit form of scene structure without supervision. However, the implicit representation learned in most existing methods is non-expandable and cannot be inferred online for novel scenes, which makes the learned representation difficult to be applied across different reinforcement learning (RL) tasks. In this work, we introduce Scene Memory Network (SMN) to achieve online spatial memory construction and expansion for view rendering in novel scenes. SMN models the camera projection and back-projection as spatially aware memory control processes, where the memory values store the information of the partial 3D area, and the memory keys indicate the position of that area. The memory controller can learn the geometry property from observations without the camera's intrinsic parameters and depth supervision. We further apply the memory constructed by SMN to exploration and navigation tasks. The experimental results reveal the generalization ability of our proposed SMN in large-scale scene synthesis and its potential to improve the performance of spatial RL tasks.

An ERP measure of non-conscious memory reveals dissociable implicit processes in human recognition using an open-source automated analytic pipeline.

Non-conscious processing of human memory has traditionally been difficult to objectively measure and thus understand. A prior study on a group of hippocampal amnesia (N = 3) patients and healthy controls (N = 6) used a novel procedure for capturing neural correlates of implicit memory using event-related potentials (ERPs): old and new items were equated for varying levels of memory awareness, with ERP differences observed from 400 to 800 ms in bilateral parietal regions that were hippocampal-dependent. The current investigation sought to address the limitations of that study by increasing the sample of healthy subjects (N = 54), applying new controls for construct validity, and developing an improved, open-source tool for automated analysis of the procedure used for equating levels of memory awareness. Results faithfully reproduced prior ERP findings of parietal effects that a series of systematic control analyses validated were not contributed to nor contaminated by explicit memory. Implicit memory effects extended from 600 to 1000 ms, localized to right parietal sites. These ERP effects were found to be behaviorally relevant and specific in predicting implicit memory response times, and were topographically dissociable from other traditional ERP measures of implicit memory (miss vs. correct rejections) that instead occurred in left parietal regions. Results suggest first that equating for reported awareness of memory strength is a valid, powerful new method for revealing neural correlates of non-conscious human memory, and second, behavioral correlations suggest that these implicit effects reflect a pure form of priming, whereas misses represent fluency leading to the subjective experience of familiarity.

Prevalence and pathological correlates of unawareness of memory impairment in non‐demented individuals with autosomal dominant Alzheimer’s disease: an item‐level investigation of the Memory Complaints Scale

AbstractBackgroundAwareness of memory was previously found to be reduced in the pre‐dementia stages, reaching unawareness/anosognosia 6‐years before dementia onset in individuals who carry the PSEN1 E280A mutation for autosomal dominant Alzheimer’s disease (Vannini et al.,2021). Whether there are potential differences in awareness for specific types of situations involving memory as well as their association with molecular markers of AD disease progression in preclinical AD is unknown. Here, we investigated memory awareness on an item‐level basis as well as its relationship to neocortical amyloid and regional tau levels in non‐demented mutation carriers and non‐carrier family members.MethodA total of 119 Colombian kindred members, 56 carriers (7 mildly impaired) and 63 non‐carriers were included (Table.1). Awareness indexes were calculated using participant and study‐partner discrepancy scores for each of the 15 questions of the Memory Complaint Scale (Spanish version). A score of ≥0 indicates that the participant is aware and <0 unaware. A subset of 67 kindred members (N = 31 carriers, 1 impaired) underwent amyloid (PiB) and tau (FTP) scans. For each question, odds ratio and Fisher’s exact test were used to evaluate prevalence of awareness/unawareness in carriers and non‐carriers. Pearson correlations, corrected for multiple comparisons, were used to assess the associations between awareness and pathology in the mutation carriers.ResultMutation carriers had significantly decreased overall awareness (p = 0.03), increased mean cortical amyloid (p<0.001) and inferior temporal tau (p = 0.001), compared to non‐carriers. Two questions (items 10 and 15), showed significantly lower awareness in the carriers than non‐carriers (both p = 0.002, Table.2). These results remained significant after removing impaired carriers. In carriers, decreased awareness was related to increased tau for 5/15 (33%) questions (Table.3 and Figure.1). No significant associations were found between awareness and amyloid.ConclusionOur results support previous findings that awareness is decreased in pre‐dementia stages of AD and related to tau, and not to amyloid pathology (Gagliardi et al.,2021). Importantly, we found that loss of awareness of specific memory items could differentiate carriers from non‐carriers. These findings support the usefulness of study‐partner‐reported cognitive decline. Individuals who become unaware of cognitive changes may represent a specific risk group to harbor pathology and develop AD dementia.

Torsion Geometry 5-Fold Symmetry, Anholonomic Phases, Klein Bottle Logophysics, Chaos, Resonance: Applications Towards a Novel Paradigm for the Neurosciences and Consciousness

Torsion Geometry 5-Fold Symmetry, Anholonomic Phases, Klein Bottle Logophysics, Chaos, Resonance: Applications Towards a Novel Paradigm for the Neurosciences and Consciousness

Subjective Complaints are Similar in Subjective Cognitive Decline and Early-Stage Alzheimer's Disease when Assessed in a Memory Clinic Setting.

Subjective cognitive complaints are generally poorly associated with objective memory functioning in older persons. Subjective cognitive decline (SCD) is a key feature in SCD and amnestic mild cognitive impairment (aMCI) which both can represent early Alzheimer's disease (AD). The aim of this study was to assess how memory clinic patients with SCD, MCI and mild AD dementia scored on 3 different complaint measures and if the format of assessment had an impact on the association with cognitive functioning, age, and depressive symptoms. We included 17 SCD patients, 17 aMCI patients, 17 patients with mild AD, and 30 controls. Complaints were assessed with the Cognitive Change Index (CCI), the Subjective Memory Complaints (SMC) scale, and the Memory Complaint Questionnaire (MAC-Q). There were no significant differences between the total scores in the patient groups on the questionnaires. However, significant differences were found in the number of patients classified with impairment when using the CCI, the SMC, and the MAC-Q. Scores on all questionnaires were significantly associated with depressive symptoms, and significant associations with age, gender, and Addenbrookes Cognitive Examination score were found for the SMC. In patients with cognitive dysfunction, lower memory awareness significantly predicted fewer cognitive complaints. SCD patients in a memory clinic setting report the same degree of cognitive impairment as patients with aMCI and mild dementia, and in a hospital-based cohort we extend previous findings from healthy controls, that definition of SCD may depend on the format of assessment.

Historic Designation Planning for the Nicodemus National Historic Site and Colonel Allensworth State Historic Park: A Cross-Case Analysis of Representation in Public Memory, Equity-Based Preservation Planning, and Maintenance Backlogs

Abstract: The hidden histories of Black towns from post-Reconstruction, namely Nicodemus, Kansas, and Colonel Allensworth, California, can provide public awareness of the black experience. In this article, we draw upon previous research by the authors to further emphasize and compare designation outcomes related to representation, equity-based preservation planning, and maintenance backlogs issues. Key partners from both sites were interviewed and central preservation planning documents were analyzed. Key findings emphasized limited opportunities for community involvement, and historic structures preservation and maintenance work. Additionally, some action has been taken by the National Park Service and California State Parks to improve diversity, equity, and inclusion. Despite these efforts, there are still alarming indicators of systematic underrepresentation within both systems. Recommendations and best practices include increasing racial equity and diversity training, evaluating diversity hiring practices and public memory awareness, practicing inclusive partnership planning, redesigning maintenance backlog funding systems, engaging economic revitalization, practicing inclusive and digitally enhanced programming, and expanding virtual presence. Consideration of this study's recommendations could provide meaningful preservation change for the Nicodemus National Historic Site, Allensworth State Historic Park, and other similar African American historical locations.

Deep continual hashing with gradient-aware memory for cross-modal retrieval

Cross-modal hashing (CMH) has become widely used for large-scale multimedia retrieval. However, most current CMH methods focus on the closed retrieval scenario, not the real-world environments, i.e., complex and changing semantics. When data containing new class objects emerge, the current CMH has to retrain the model on all history training data, not the new data, to accommodate new semantics, but the never-stop upload of data on the Internet makes this impractical. In this paper, we devise a deep hashing method called Continual Cross-Modal Hashing with Gradient Aware Memory (CCMH-GAM) for learning binary codes of multi-label cross-modal data with increasing categories. CCMH-GAM is a two-step hashing architecture, one hashing network learns to hash the increasing semantics of data, i.e., label, into the semantic codes, and other modality-specific hashing networks learn to map data into the corresponding semantic codes. Specifically, to keep the encoding ability for old semantics, a regularization based on accumulating low-storage label-code pairs is designed for the former network. For the modality-specific networks, we propose a memory construction method via approximating the full episodic gradients of all data by some exemplars and derive its fast implementation with the upper bound of approximation error. Based on this memory, we propose a gradient projection method to theoretically improve the probability of old data’s code being unchanged after updating the model. Extensive experiments on three datasets demonstrate that CCMH-GAM can continually learn hash functions and yield state-of-the-art retrieval performance.

Evolution of awareness for cognitive decline across several cognitive domains in stable vs clinically progressing participants.

AbstractBackgroundAwareness of memory impairment has been shown to vary across the AD spectrum with an initial heightened awareness at the preclinical stage, and a subsequent loss of awareness with AD progression (Hanseeuw et al.,2020). Whether there are potential differences in the evolution of awareness for cognitive domains other than memory is unknown. In this study, we investigated the evolution of awareness in visuospatial, language, planning, divided attention and organization in cognitively older adults that later progressed versus those who remained stable.MethodsOur study included 621 cognitively normal (CN) ADNI participants (Tab1). Individuals were considered Stable or Progressors (n = 147) on the basis on the Clinical Dementia Rating scale global score (stable: scores at first and last observation both 0, progression:last score≥0.5). Cognitive complaints were recorded using the Everyday Cognition (ECog) questionnaire, using both participant’s and informant’s average complaints in each of the six subscales: divided attention, language, memory, organization, planning and visuo‐spatial. Generalized linear mixed‐effect models were run to predict complaints within each subscale, using time, the source of complaint (informant vs participant), and their interaction as independent variables, adjusting for age, gender and education. Jonhson‐Neyman Points (JNP) were computed for significant interactions, and simple slopes analyses were performed.ResultsStable participants displayed a similar evolution of both informant and participant complaints (Fig1, left panels). Among progressors, all models showed significant interactions with participants expressing greater, and subsequent lower complaints than informants (Fig1, right panels). JNP analyses revealed that, while on some subscales this transition occurred only after/close to progression (i.e., divided attention, language, memory and organization), it could be observed years before progression in others (i.e., planning and visuo‐spatial).ConclusionsProgressive participants expressed greater, and then lower complaints as compared to their informant, demonstrating a transition from heightened to reduced awareness over time. Our results attest that, while most studies are focusing on memory awareness, other domains might also show early changes in awareness. This advocates for including the informant’s appraisal in the examination process, as well as to expand the focus to other cognitive abilities.

Syntactic awareness matters: uncovering reading comprehension difficulties in Hong Kong Chinese-English bilingual children.

This study examined whether syntactic awareness was related to reading comprehension difficulties in either first language (L1) Chinese or second language (L2) English, or both, among Hong Kong Chinese-English bilingual children. Parallel L1 and L2 metalinguistic and reading measures, including syntactic word-order, morphological awareness, phonological awareness, vocabulary, word reading, reading comprehension, and cognitive measures of nonverbal intelligence and working memory, were administered to 224 fourth-graders. Five groups of comprehenders were identified using a regression approach: (1) 12 poor in Chinese-only (PC), (2) 18 poor in English-only (PE), (3) six poor in both Chinese and English (PB), (4) 14 average in both Chinese and English (AB), and (5) seven good in both (GB). The results of multivariate analyses of covariance showed that (1) the PB group performed worse than the AB and GB groups in both L1 Chinese and L2 English syntactic awareness; (2) the PC and PE groups performed worse than the AB and GB groups in Chinese syntactic awareness; (3) the PE group had lower performance than the PC, AB, and GB groups in English syntactic awareness; and (4) no significant group difference was found in L2 morphological awareness or vocabulary across both languages. By suggesting that weakness insyntactic awareness can serve asa universal indicator for identifying poor comprehenders in either or both L1Chinese and L2English among Hong Kong Chinese-Englishbilingual children, these findings demonstrate the fundamental role of syntacticawareness in bilingual reading comprehension.

Environmental management education using immersive virtual reality in asthmatic children in Korea: a randomized controlled study (secondary publication)

Purpose: Awareness of environmental control is considered a significant influence on the performance of asthma self-management behaviors, which are involved in maintaining effective asthma control. This study aimed to investigate whether immersive virtual reality (VR) education is effective in environmental control education for asthmatic children in Korea.Methods: Thirty asthmatic children aged 9 to 13 years with aeroallergen sensitization were enrolled. Environmental control education for asthmatic participants was performed using immersive VR (VR group) or conventional leaflets provided by asthma specialists (control group). Five questionnaires, on awareness of environmental control, memory, assessment of intent to act, a satisfaction test, and an asthma control test (ACT), were used to estimate the effects of education.Results: The scores for awareness of environmental control, memory, and intent to act significantly increased after education in both groups, and the scores remained high until 4 weeks after education. Both groups' ACT scores were consistently high before and 4 weeks after education. Satisfaction scores were very high in the VR group.Conclusion: The increased scores in awareness of environmental control and intent to act indicate that the environmental control education using VR is worthy of attention as an effective educational tool for asthma management. Further developed techniques, including active environmental interventions by participants in VR, could be applied to effective asthma management.

Environmental management education using immersive virtual reality in asthmatic children in Korea: a randomized controlled study (secondary publication)

Awareness of environmental control is considered a significant influence on the performance of asthma self-management behaviors, which are involved in maintaining effective asthma control. This study aimed to investigate whether immersive virtual reality (VR) education is effective in environmental control education for asthmatic children in Korea. Thirty asthmatic children aged 9 to 13 years with aeroallergen sensitization were enrolled. Environmental control education for asthmatic participants was performed using immersive VR (VR group) or conventional leaflets provided by asthma specialists (control group). Five questionnaires, on awareness of environmental control, memory, assessment of intent to act, a satisfaction test, and an Asthma Control Test (ACT), were used to estimate the effects of education. The scores for awareness of environmental control, memory, and intent to act significantly increased after education in both groups, and the scores remained high until 4 weeks after education. Both groups’ ACT scores were consistently high before and 4 weeks after education. Satisfaction scores were very high in the VR group. The increased scores in awareness of environmental control and intent to act indicate that the environmental control education using VR is worthy of attention as an effective educational tool for asthma management. Further developed techniques, including active environmental interventions by participants in VR, could be applied to effective asthma management.

Anterior Cingulate Cortex Signals the Need to Control Intrusive Thoughts during Motivated Forgetting.

How do people limit awareness of unwanted memories? When such memories intrude, a control process engages the right DLPFC (rDLPFC) to inhibit hippocampal activity and stop retrieval. It remains unknown how the need for control is detected, and whether control operates proactively to prevent unwelcome memories from being retrieved, or responds reactively, to counteract intrusions. We hypothesized that dorsal ACC (dACC) detects the emergence of an unwanted trace in awareness and transmits the need for inhibitory control to rDLPFC. During a memory suppression task, we measured in humans (both sexes) trial-by-trial variations in the theta power and N2 amplitude of dACC, two EEG markers that are thought to reflect the need for control. With simultaneous EEG-fMRI recordings, we tracked interactions among dACC, rDLPFC, and hippocampus during suppression. We found a clear role of dACC in detecting the need for memory control and upregulating prefrontal inhibition. Importantly, we identified distinct early (300–450 ms) and late (500–700 ms) dACC contributions, suggesting both proactive control before recollection and reactive control in response to intrusions. Stronger early activity was associated with reduced hippocampal activity and diminished BOLD signal in dACC and rDLPFC, suggesting that preempting retrieval reduced overall control demands. In the later window, dACC activity was larger, and effective connectivity analyses revealed robust communication from dACC to rDLPFC and from rDLPFC to hippocampus, which are tied to successful forgetting. Together, our findings support a model in which dACC detects the emergence of unwanted content, triggering top-down inhibitory control, and in which rDLPFC countermands intruding thoughts that penetrate awareness.SIGNIFICANCE STATEMENT Preventing unwanted memories from coming to mind is an adaptive ability of humans. This ability relies on inhibitory control processes in the prefrontal cortex to modulate hippocampal retrieval processes. How and when reminders to unwelcome memories come to trigger prefrontal control mechanisms remains unknown. Here we acquired neuroimaging data with both high spatial and temporal resolution as participants suppressed specific memories. We found that the anterior cingulate cortex detects the need for memory control, responding both proactively to early warning signals about unwelcome content and reactively to intrusive thoughts themselves. When unwanted traces emerge in awareness, anterior cingulate communicates with prefrontal cortex and triggers top-down inhibitory control over the hippocampus through specific neural oscillatory networks.

Subjective Cognitive Decline Is More Accurate When Metamemory Is Better.

ObjectiveSubjective cognitive decline (SCD) has emerged as one of the first manifestations of Alzheimer’s disease (AD). However, discrepancies in its relationship with tests of memory and other cognitive abilities have hindered SCD’s diagnostic utility. Inter-individual heterogeneity in metamemory, or memory awareness, and the use of clinical measures of cognition lacking sensitivity to early cognitive dysfunction, may contribute to these discrepancies. We aimed to assess if the relationship between SCD and markers of early cognitive dysfunction is moderated by metamemory abilities.MethodsThe sample included 79 cognitively healthy older adults (77% female, 68% White, and 32% Black participants) with a mean age of 74.4 (SD = 6.1) and 15.9 (SD = 2.7) years of education. Metamemory was assessed using an episodic Feeling of Knowing test with four 5-item trials. Outcome measures included a resolution metric defined as a gamma correlation reflecting the accuracy of item-level predictions (“Will you know the correct answer?”). Early cognitive dysfunction was measured through the Loewenstein-Acevedo Scale for Semantic Interference and Learning (LASSI-L) and the Short-Term Memory Binding Test (STMB), measures sensitive to preclinical AD. SCD was assessed with a 20-item questionnaire that asked participants to compare themselves to others their age on a 7-point Likert scale. Regression analyses examined whether a potential relation between SCD and early cognitive dysfunction was moderated by metamemory.ResultsSubjective cognitive decline was associated with susceptibility to semantic proactive interference such that greater complaints were associated with increased susceptibility to semantic proactive interference (b = −0.30, p = 0.003) only. Metamemory moderated the association between SCD and susceptibility to and recovery of semantic proactive interference such that those with more accurate metamemory showed a stronger association between increased complaints and susceptibility to semantic proactive interference (b = −0.71, p = 0.005; b = −0.62, p = 0.034). Metamemory, however, did not moderate the association of SCD with retroactive semantic interference nor short term memory binding.DiscussionThe accuracy of an individual’s metamemory, specifically their ability to adjust moment to moment predictions in line with their performance, can influence the extent to which SCD maps onto objective cognition. Such self-referential assessment should be considered when interpreting SCD.