Twin Memory

In this article, I examine a new concept of “Twin Memory’ which has emerged in memory classification research of conscious and unconscious memory representations. It is to analyse the presence of twin memory among the various memory systems, and also to provide a platform for the twin memory “anatomy” in the field of cognitive science, neuropsychology and neuroscience

Names and their meanings: A dual-process account of proper-name encoding and retrieval

The ability to pick out a unique entity with a proper name is an important component of human language. It has been a primary focus of research in the philosophy of language since the nineteenth century. Brain-based evidence has shed new light on this capacity, and an extensive literature indicates the involvement of distinct fronto-temporal and temporo-occipito-parietal association cortices in proper-name retrieval. However, comparatively few efforts have sought to explain how memory encoding processes lead to the later recruitment of these distinct regions at retrieval. Here, we provide a unified account of proper-name encoding and retrieval, reviewing evidence that socio-emotional and unitized encoding subserve the retrieval of proper names via anterior-temporal-prefrontal activations. Meanwhile, non-unitized item-item and item-context encoding support subsequent retrieval, largely dependent on the temporo-occipito-parietal cortex. We contend that this well-established divergence in encoding systems can explain how proper names are later retrieved from distinct neural structures. Furthermore, we explore how evidence reviewed here can inform a century-and-a-half-old debate about proper names and the meanings they pick out

Memories for Life: A Review of the Science and Technology

This paper discusses scientific, social and technological aspects of memory. Recent developments in our understanding of memory processes and mechanisms, and their digital implementation, have placed the encoding, storage, management and retrieval of information at the forefront of several fields of research. At the same time, the divisions between the biological, physical and the digital worlds seem to be dissolving. Hence opportunities for interdisciplinary research into memory are being created, between the life sciences, social sciences and physical sciences. Such research may benefit from immediate application into information management technology as a testbed. The paper describes one initiative, Memories for Life, as a potential common problem space for the various interested disciplines

Temporally Graded Activation of Neocortical Regions in Response to Memories of Different Ages

The temporally graded memory impairment seen in many neurobehavioral disorders implies different neuroanatomical pathways and/or cognitive mechanisms involved in storage and retrieval of memories of different ages. A dynamic interaction between medial-temporal and neocortical brain regions has been proposed to account for memory\u27s greater permanence with time. Despite considerable debate concerning its time-dependent role in memory retrieval, medial-temporal lobe activity has been well studied. However, the relative participation of neocortical regions in recent and remote memory retrieval has received much less attention. Using functional magnetic resonance imaging, we demonstrate robust, temporally graded signal differences in posterior cingulate, right middle frontal, right fusiform, and left middle temporal regions in healthy older adults during famous name identification from two disparate time epochs. Importantly, no neocortical regions demonstrated greater response to older than to recent stimuli. Our results suggest a possible role of these neocortical regions in temporally dating items in memory and in establishing and maintaining memory traces throughout the lifespan. Theoretical implications of these findings for the two dominant models of remote memory functioning (Consolidation Theory and Multiple Trace Theory) are discussed

Brain mechanisms of successful recognition through retrieval of semantic context

Episodic memory is associated with the encoding and retrieval of context information and with a subjective sense of reexperiencing past events. The neural correlates of episodic retrieval have been extensively studied using fMRI, leading to the identification of a "general recollection network" including medial temporal, parietal, and prefrontal regions. However, in these studies, it is difficult to disentangle the effects of context retrieval from recollection. In this study, we used fMRI to determine the extent to which the recruitment of regions in the recollection network is contingent on context reinstatement. Participants were scanned during a cued recognition test for target words from encoded sentences. Studied target words were preceded by either a cue word studied in the same sentence (thus congruent with encoding context) or a cue word studied in a different sentence (thus incongruent with encoding context). Converging fMRI results from independently defined ROIs and whole-brain analysis showed regional specificity in the recollection network. Activity in hippocampus and parahippocampal cortex was specifically increased during successful retrieval following congruent context cues, whereas parietal and prefrontal components of the general recollection network were associated with confident retrieval irrespective of contextual congruency. Our findings implicate medial temporal regions in the retrieval of semantic context, contributing to, but dissociable from, recollective experience

The Effect of Limited Attention and Delay on Negative Arousing False Memories

Previous research has shown that, in comparison to neutral stimuli, false memories for high arousing negative stimuli are greater after very fast presentation and limited attention at study. However, full compared to limited attention conditions still produce comparably more false memories for all stimuli types. Research has also shown that emotional stimuli benefit from a period of consolidation. What effect would such consolidation have on false memory formation even when attention is limited at study? The aim of the present study was to investigate the effect of fast presentation on false memory production for negatively-arousing and neutral items over time using the DRM paradigm. Sixty-Eight participants studied Negative and neutral DRM lists with fast or slow presentation conditions. Half completed a recognition test immediately and half completed a recognition test after one-week. Results revealed that, for fast presentation, negative critical lures increased after one week and were comparable to negative critical lures in the slow presentation encoding conditions. Neutral critical lures in the fast presentation condition did not change and remained lower compared to the slow presentation condition. These findings are the first demonstration that arousing negative false memories can increase over time when attention at encoding is limited

Memory in autism spectrum disorder: a meta-analysis of experimental studies

To address inconsistencies in the literature on memory in Autism Spectrum Disorder (ASD), we report the first ever meta-analysis of short-term (STM) and episodic long-term (LTM) memory in ASD, evaluating the effects of type of material, type of retrieval and the role of inter-item relations. Analysis of 64 studies comparing individuals with ASD and typical development (TD) showed greater difficulties in ASD compared to TD individuals in STM (Hedges’ g=-0.53 [95%CI -0.90; -0.16], p=.005, I²=96%) compared to LTM (g=-0.30 [95%CI -0.42; -0.17], p<.00001, I²=24%), a small difficulty in verbal LTM (g=-0.21, p=.01), contrasting with a medium difficulty for visual LTM (g= -0.41, p=.0002) in ASD compared to TD individuals. We also found a general diminution in free recall compared to cued recall and recognition (LTM, free recall: g=-0.38, p<.00001, cued recall: g=-0.08, p=.58, recognition: g=-0.15, p=.16; STM, free recall: g=-0.59, p=.004, recognition: g=-0.33, p=.07). We discuss these results in terms of their relation to semantic memory. The limited diminution in verbal LTM and preserved overall recognition and cued recall (supported retrieval) may result from a greater overlap of these tasks with semantic long-term representations which are overall preserved in ASD. By contrast, difficulties in STM or free recall may result from less overlap with the semantic system or may involve additional cognitive operations and executive demands. These findings highlight the need to support STM functioning in ASD and acknowledge the potential benefit of using verbal materials at encoding and broader forms of memory support at retrieval to enhance performance

Prior knowledge contribution to declarative learning. A study in amnesia, aging and Alzheimer's disease

L'étude expérimentale de la mémoire humaine a connu deux moments historiques dans les soixante dernières années. 1957 marque la découverte du rôle du lobe temporal interne bilatéral dans l'apprentissage conscient, déclaratif. 1997 marque la découverte de deux systèmes de mémoire déclarative, épisodique et sémantique. Ces découvertes résultent d'études de cas en neuropsychologie. Cette thèse s'inscrit dans la tradition neuropsychologique: sa genèse doit tout à un patient souffrant d'une forme atypique d'amnésie développementale, le patient KA. Son point de départ est une étude de cas approfondie, avec deux résultats surprenants. Malgré une amnésie sévère, KA dispose de connaissances sémantiques exceptionnelles. Par ailleurs, il montre des capacités préservées d'apprentissage explicite, mais uniquement pour des stimuli concrets, pas abstraits. En conséquence, cette thèse a exploré deux pistes de recherche. Premièrement, nous avons caractérisé les processus préservés d'apprentissage déclaratif et l'anatomie cérébrale chez ce patient. Deuxièmement, nous avons étudié le rôle des connaissances préalables dans l'apprentissage: comment ce que l'on sait influence ce dont nous nous souvenons ? Une première série d'expériences montre chez ce patient une atteinte sévère et sélective de l'ensemble du système hippocampique, alors que les structures sous- hippocampiques (cortex entorhinal, périrhinal et parahippocampique) sont préservées. Malgré une amnésie épisodique sévère, nous montrons des connaissances sémantiques supranormales et des aptitudes d'apprentissage explicite rapide. Ces aptitudes sont toutefois restreintes aux stimuli associés à des connaissances préalables. Une seconde série d'expériences explore l'hypothèse selon laquelle les connaissances préalables facilitent l'apprentissage en mémoire déclarative, même dans les situations où le lobe temporal interne est fragilisé, comme dans le vieillissement, ou lésé, comme chez le patient KA ou dans la maladie d'Alzheimer. Nos résultats suggèrent l'existence de processus d'apprentissage rapide en mémoire déclarative, indépendants du système hippocampique et sensibles à la présence de représentations préexistantes. Ces processus semblent affectés par la maladie d'Alzheimer, et ce en lien avec un défaut d'activité des régions sous-hippocampiques antérieures. A l'inverse, les sujets âgés sains peuvent utiliser les connaissances préalables et pourraient ainsi compenser le déclin de la mémoire associative. Ce travail s'accorde avec les modèles postulant une dissociation fonctionnelle au sein du lobe temporal interne pour l'apprentissage déclaratif. Il soutient les propositions neurocognitives et computationnelles récentes, suggérant une voie d'apprentissage néocortical rapide mobilisable dans certaines circonstances. Il met en exergue la dynamique des apprentissages en mémoire déclarative et notamment l'intrication fondamentale entre "savoir" et "se souvenir". Ce que je sais a un impact profond sur ce dont je vais me souvenir. Cette thèse permet d'envisager de nouveaux outils cognitifs pour le diagnostic de la maladie d'Alzheimer. De plus, il semble que des lésions temporales internes auront un impact distinct sur l'apprentissage selon le statut des informations à mémoriser en mémoire à long terme, offrant un regard nouveau sur les effets stimulus-dépendants dans l'amnésie. Une considération approfondie des connaissances préalables associées au contenu de nos expériences, et leur caractérisation détaillée, est requise pour affiner les modèles de la mémoire déclarative. Ces résultats apportent de nouvelles pistes de recherche quant aux circonstances épargnant l'apprentissage, notamment associatif, lors du vieillissement. Plus généralement, ils contribuent à la compréhension des déterminants d'un apprentissage réussi, en mettant l'accent sur les recouvrements entre processus de récupération et d'acquisition. Des applications potentielles en découlent dans le domaine éducatif.The experimental study of human memory has had two historic moments in the last sixty years. 1957 marks the discovery of the role of the medial temporal lobes in conscious learning. 1997 marks the discovery of two systems of declarative memory, namely episodic and semantic memories. These major breakthroughs are owed to clinical case studies in neuropsychology. This thesis follows on from the neuropsychological tradition: its genesis owes everything to a patient suffering from an atypical form of developmental amnesia, the patient KA. The starting point of this work was a thorough neuropsychological study of this patient. Two striking findings shortly arose. First, despite lifelong amnesia, KA had acquired exceptional levels of knowledge about the world. Second, remaining explicit learning abilities were restricted to meaningful, not meaningless, memoranda. As a consequence, we have investigated two research pathways in that thesis. First, we aimed at better characterizing preserved learning abilities and brain structure of the patient KA. Second, our goal was to explore how prior knowledge affects new declarative learning or, put simply, how do we learn what we know? In a first series of behavioural and neuroimaging experiments, we have shown in this patient a severe and selective damage of the whole extended hippocampal system, but preserved subhippocampal structures (entorhinal, perirhinal and parahippocampal cortex). The patient suffers from severe episodic amnesia, but we bring striking evidence for supranormal semantic knowledge as well as normal explicit learning skills. These skills were, however, restricted to familiar stimuli, that is, stimuli carrying pre-experimental knowledge. In a second series of behavioural and neuroimaging experiments, we explored the hypothesis that prior knowledge can facilitate new learning in declarative memory, even in aging or in situations where structures of the medial temporal lobe are or injured, as in amnesia or Alzheimer's disease. Our results suggest the existence of processes allowing fast learning in declarative memory, independently of the hippocampal system, and that are sensitive to the presence of pre-existing representations in long-term memory. Such learning processes appear to be selectively affected by Alzheimer's disease at the pre-dementia stage, in relation to a lack of activation of subhippocampal regions. In contrast, healthy elderly were able to rely on these learning processes to compensate for the decline in associative memory associated with aging. This work lends support to the models postulating a functional dissociation with respect to learning in declarative memory. It indeed strengthens recent neurocognitive and computational accounts that suggest a rapid neocortical learning path under certain circumstances. It highlights the dynamics of learning in declarative memory and in particular the fundamental entanglement between "knowing" and "remembering". What I know profoundly impacts what I will remember. The present thesis points towards new cognitive tools for the diagnosis of Alzheimer's disease. It further brings evidence that medial temporal lesions differentially impact learning depending on the status of the memoranda in long-term memory, which sheds a new light on material-specific effects in amnesia. Our work speaks for a thorough consideration of whether the contents of events have prior representations within long-term memory, and to further better characterize their nature if we are to better understand learning mechanisms. It also brings additional clues for a deeper understanding of how learning and memory can be preserved in aging. More generally, it contributes to a better understanding of the factors determining successful learning, with a focus on how retrieval and acquisition processes overlap during learning. Such findings have potential applications in the educational field

Subjective experience of episodic memory and metacognition: a neurodevelopmental approach.

Episodic retrieval is characterized by the subjective experience of remembering. This experience enables the co-ordination of memory retrieval processes and can be acted on metacognitively. In successful retrieval, the feeling of remembering may be accompanied by recall of important contextual information. On the other hand, when people fail (or struggle) to retrieve information, other feelings, thoughts, and information may come to mind. In this review, we examine the subjective and metacognitive basis of episodic memory function from a neurodevelopmental perspective, looking at recollection paradigms (such as source memory, and the report of recollective experience) and metacognitive paradigms such as the feeling of knowing). We start by considering healthy development, and provide a brief review of the development of episodic memory, with a particular focus on the ability of children to report first-person experiences of remembering. We then consider neurodevelopmental disorders (NDDs) such as amnesia acquired in infancy, autism, Williams syndrome, Down syndrome, or 22q11.2 deletion syndrome. This review shows that different episodic processes develop at different rates, and that across a broad set of different NDDs there are various types of episodic memory impairment, each with possibly a different character. This literature is in agreement with the idea that episodic memory is a multifaceted process