Differences in predictive factors for post-traumatic stress disorder encompassing partial PTSD and full PTSD: a cross-sectional study among individuals exposed to the November 13, 2015 Paris attacks.

Background: When faced with a surge of physically injured individuals, especially following a traumatic event like an attack, frontline practitioners prioritize early triage. Detecting potential psychological injuries soon after such events remains challenging. Some individuals might develop post-traumatic stress disorder (PTSD) according to DSM-V criteria. Others may exhibit PTSD symptoms without meeting full diagnostic criteria, termed partial or sub-syndromal PTSD, a less-explored area in literature. This study aims to identify predictive factors for both full and partial PTSD. Method: In a cohort of victims of the 2015 Paris attacks, multinomial logistic regressions explored predictive factors for partial or full PTSD status 8 to 18 months post-attacks. Analyses considered pre, peri, and posttraumatic factors chosen from literature review and univariate analysis within each group. Results: Within the cohort, 50 individuals showed no signs of PTSD, 35 experienced partial PTSD, and 30 presented with full PTSD. After logistic regression, risk factors associated with full PTSD included a history of trauma (OR = 1.30, CI [1.02-1.66], p < 0.05), the intensity of peri-traumatic physical reactions (OR = 1.22, CI [1.09-1.36], p < 0.001), the difficulties in suppressing intrusive thoughts (OR = 1.11, CI [1.02-1.21], p < 0.013). Only the intensity of peri-traumatic physical reactions emerged as a risk factor for partial PTSD (OR = 1.13, [CI 1.02-1.24], p < 0.001). Discussion: This study revealed that a history of trauma, the intensity of peri-traumatic physical reactions (e.g., tachycardia, trembling, flushes, numbness.), and the difficulties in suppressing intrusive thoughts constitute risk factors for the development of full PTSD. Moreover, the study identified that only the intensity of peri-traumatic physical reactions emerged as a risk factor for partial PTSD. These findings seem to underscore the significance of peri-traumatic experiences in influencing the development of post-traumatic stress symptoms. Conclusion: This study emphasizes the significance of examining peri-traumatic reactions in PTSD development, suggesting its potential as a straightforward screening tool for post-traumatic stress disorder. It also underscores the influence of prior traumatic experiences, before de novo traumatization, in shaping vulnerability to PTSD and illuminates the crucial role of compromised control of intrusive thoughts that could perpetuate PTSD.

Linking structural and functional changes during aging using multilayer brain network analysis.

Brain structure and function are intimately linked, however this association remains poorly understood and the complexity of this relationship has remained understudied. Healthy aging is characterised by heterogenous levels of structural integrity changes that influence functional network dynamics. Here, we use the multilayer brain network analysis on structural (diffusion weighted imaging) and functional (magnetoencephalography) data from the Cam-CAN database. We found that the level of similarity of connectivity patterns between brain structure and function in the parietal and temporal regions (alpha frequency band) is associated with cognitive performance in healthy older individuals. These results highlight the impact of structural connectivity changes on the reorganisation of functional connectivity associated with the preservation of cognitive function, and provide a mechanistic understanding of the concepts of brain maintenance and compensation with aging. Investigation of the link between structure and function could thus represent a new marker of individual variability, and of pathological changes.

Effects of sleep disturbances and circadian rhythms modifications on cognition in breast cancer women before and after adjuvant chemotherapy: the ICANSLEEP-1 protocol.

BACKGROUND: Many patients treated for breast cancer (BC) complain about cognitive difficulties affecting their daily lives. Recently, sleep disturbances and circadian rhythm disruptions have been brought to the fore as potential contributors to cognitive difficulties in patients with BC. Yet, studies on these factors as well as their neural correlates are scarce. The purpose of the ICANSLEEP-1 (Impact of SLEEP disturbances in CANcer) study is to characterize sleep using polysomnography and its relationship with the evolution of cognitive functioning at both the behavioral and the neuroanatomical levels across treatment in BC patients treated or not with adjuvant chemotherapy. METHODS: ICANSLEEP-1 is a longitudinal study including BC patients treated with adjuvant chemotherapy (n = 25) or not treated with adjuvant chemotherapy (n = 25) and healthy controls with no history of BC (n = 25) matched for age (45-65 years old) and education level. The evaluations will take place within 6 weeks after inclusion, before the initiation of chemotherapy (for BC patients who are candidates for chemotherapy) or before the first fraction of radiotherapy (for BC patients with no indication for chemotherapy) and 6 months later (corresponding to 2 weeks after the end of chemotherapy). Episodic memory, executive functions, psychological factors, and quality of life will be assessed with validated neuropsychological tests and self-questionnaires. Sleep quantity and quality will be assessed with polysomnography and circadian rhythms with both actigraphy and saliva cortisol. Grey and white matter volumes, as well as white matter microstructural integrity, will be compared across time between patients and controls and will serve to further investigate the relationship between sleep disturbances and cognitive decline. DISCUSSION: Our results will help patients and clinicians to better understand sleep disturbances in BC and their relationship with cognitive functioning across treatment. This will aid the identification of more appropriate sleep therapeutic approaches adapted to BC patients. Improving sleep in BC would eventually help limit cognitive deficits and thus improve quality of life during and after treatments. TRIAL REGISTRATION: NCT05414357, registered June 10, 2022. PROTOCOL VERSION: Version 1.2 dated March 23, 2022.

Collective memory: between individual systems of consciousness and social systems.

Following a long period of neglect, research on different facets of collective memory is now developing apace in the human and social sciences, as well as at their interface with psychology and neuroscience. This resolutely multidisciplinary renewal of interest in memory sciences has given rise to a plethora of concepts with diverse meanings (e.g., social frameworks of memory, collective, shared, collaborative, social memory). The purpose of the present study was to provide a conceptual overview from a historical perspective, and above all to clarify concepts that are often used interchangeably, even though they refer to very different realities. Based on recent research in psychology and neuroscience, we use the concept of collective memory to refer to the operations of individual systems of consciousness. Collective memory is not the memory of a collective, but that of its individual members, either as members of social groups (shared memory) or as participants in social interactions (collaborative memory). Drawing on the contributions of contemporary sociology, we show that social memory is not collective memory, as it refers not to individual systems of consciousness, but to social systems. More specifically, it is the outcome of communication operations which, through redundancy and repetition, perform a continuous and selective re-imprinting of meaning that can be used for communication. Writing, printing and the new communication technologies constitute the three historical stages in the formation and development of an autonomous social memory, independent of living memories and social interactions. In the modern era, mass media fulfill an essential function of social memory, by sorting between forgetting and remembering on a planetary scale. When thinking about the articulation between collective memory and social memory, the concept of structural coupling allows us to identify two mechanisms by which individual systems of consciousness and social systems can interact and be mutually sensitized: schemas and scripts, and social roles. Transdisciplinary approach spearheads major methodological and conceptual advances and is particularly promising for clinical practice, as it should result in a better understanding of memory pathologies, including PTSD, but also cognitive disorders in cancer (chemobrain) or in neurodegenerative diseases.

Autobiographical Cerebral Network Activation in Older Adults Before and After Reminiscence Therapy: A Preliminary Report.

INTRODUCTION: Reminiscence therapy (RT), which engages individuals to evoke positive memories, has been shown to be effective in improving psychological well-being in older adults suffering from PTSD, depression, and anxiety. However, its impact on brain function has yet to be determined. This paper presents functional magnetic resonance imaging (fMRI) data to describe changes in autobiographical memory networks (AMN) in community-dwelling older adults. METHODS: This pilot study used a within-subject design to measure changes in AMN activation in 11 older adults who underwent 6 weeks of RT. In the scanner, participants retrieved autobiographical memories which were either recent or remote, rehearsed or unrehearsed. Participants also underwent a clinical interview to assess changes in memory, quality of life, mental health, and affect. FINDINGS: Compared to pretreatment, anxiety decreased (z = -2.014, p = .040) and activated significant areas within the AMN, including bilateral medial prefrontal cortex, left precuneus, right occipital cortex, and left anterior hippocampus. CONCLUSION: Although RT had subtle effects on psychological function in this sample with no evidence of impairments, including depression at baseline, the fMRI data support current thinking of the effect RT has on the AMN. Increased activation of right posterior hippocampus following RT is compatible with the Multiple Trace Theory Theory (Nadel & Moscovitch, 1997).

Musical experience prior to traumatic exposure as a resilience factor: a conceptual analysis.

Resilience mechanisms can be dynamically triggered throughout the lifecourse by resilience factors in order to prevent individuals from developing stress-related pathologies such as posttraumatic stress disorder (PTSD). Some interventional studies have suggested that listening to music and musical practice after experiencing a traumatic event decrease the intensity of PTSD, but surprisingly, no study to our knowledge has explored musical experience as a potential resilience factor before the potential occurrence of a traumatic event. In the present conceptual analysis, we sought to summarize what is known about the concept of resilience and how musical experience could trigger two key mechanisms altered in PTSD: emotion regulation and cognitive control. Our hypothesis is that the stimulation of these two mechanisms by musical experience during the pre-traumatic period could help protect against the symptoms of emotional dysregulation and intrusions present in PTSD. We then developed a new framework to guide future research aimed at isolating and investigating the protective role of musical experience regarding the development of PTSD in response to trauma. The clinical application of this type of research could be to develop pre-trauma training that promotes emotional regulation and cognitive control, aimed at populations at risk of developing PTSD such as healthcare workers, police officers, and military staffs.

Peritraumatic physical symptoms and the clinical trajectory of PTSD after a terrorist attack: a network model approach.

Introduction: Following a mass casualty event, such as the Paris terrorist attacks of 13 November 2015, first responders need to identify individuals at risk of PTSD. Physical peritraumatic symptoms involving the autonomic nervous system may be useful in this task.Objective: We sought to determine the trajectory of physical response intensity in individuals exposed to the Paris terrorist attacks using repeated measures, and to examine its associations with PTSD. Using network modelling, we examined whether peritraumatic physical symptom associations differed by PTSD status.Methods: Physical reactions were assessed using the Subjective Physical Reactions Scale at three time points: peritraumatic by retrospective recall, then current at one year (8-18 months) and three years (30-42 months) after the attacks. Interaction networks between peritraumatic physical reactions were compared according to PTSD status.Results: On the one hand, the reported intensity of physical reactions was significantly higher in the PTSD group at all time points. On the other hand, using the dynamic approach, more robust positive interactions between peritraumatic physical reactions were found in the PTSD group one and three years after the attacks. Negative interactions were found in the no-PTSD group at one year. Peritraumatic physical numbness was found to be the most central network symptom in the PTSD group, whereas it was least central in the no-PTSD group.Discussion: Network analysis of the interaction between peritraumatic physical subjective responses, particularly physical numbness, may provide insight into the clinical course of PTSD. Our knowledge of the brain regions involved in dissociation supports the hypothesis that the periaqueductal grey may contribute to the process leading to physical numbing.Conclusions: Our findings highlight the role of peritraumatic somatic symptoms in the course of PTSD. Peritraumatic physical numbness appears to be a key marker of PTSD and its identification may help to improve early triage.

Physical numbness was found to be a central symptom in people developing PTSD in our study examining peritraumatic physical symptoms related to the 2015 Paris terrorist attacks.

[Memory and traumatism: From biology to humanities]. / Mémoire et traumatisme : de la biologie aux sciences sociales.

This article is a brief Introduction to a series of articles issued from the Journée Claude Bernard, organized at the Académie Nationale de Médecine. This session had for thematic "Memory and traumatism" and was composed of presentations coming from different disciplines including biological sciences and humanities. Several publications come from the Programme 13-Novembre, devoted to a traumatic event in French society - the attacks of 13 November 2015 in Paris and its immediate suburbs - and its consequences on the construction of individual and collective memories of this tragic event.

Title: Mémoire et traumatisme : de la biologie aux sciences sociales. Abstract: Cet article est une brève Introduction à une série d'articles issus de la Journée Claude Bernard, organisée à l'Académie Nationale de Médecine le 24 novembre 2021. Cette Journée, dont le thème était « Mémoire et traumatisme ¼, avait pour originalité de présenter des travaux provenant de disciplines différentes allant des sciences biologiques aux sciences humaines et sociales. Plusieurs publications s'appuient sur le Programme 13-Novembre, qui envisage les conséquences des attentats du 13 novembre 2015 sur la construction des mémoires individuelles et collectives de cet événement dramatique.

[The Programme 13-Novembre between individual memory and collective memory]. / Le Programme 13-Novembre entre mémoire individuelle et mémoire collective.

The purpose of this article is to present the evolution of scientific work on human memory from the end of the 19th century. The work of experimental psychology and neuropsychology first dominated the scientific scene. Research in the humanities and social sciences was established in the interwar period, but without any real interaction with psychology and neurosciences. We recall the most emblematic historical works of two distinct visions of memory: those of the experimental psychologist Hermann Ebbinghaus who measured memory, on himself, from lists of meaningless syllables, and those of the sociologist Maurice Halbwachs for whom any act of memory is a social act. This disciplinary closure persisted until the end of the 20th century. A real social shift has taken place since the 2000s, with a desire to studying and understanding the interactions between individual and collective memories. In this article, the authors argue for the emergence of "sciences of memory" based on dialectic and transdisciplinarity. They draw on the Programme 13-Novembre that is emblematic of this evolution. The Programme 13-Novembre has seized upon a diversity of research tools on memory by applying them to a traumatic event in French society: the attacks of 13 November 2015 in Paris and its immediate suburbs. Its genesis, its overall architecture and several of its components are presented here, as well as a few results already published. In addition to its theoretical scope, this work has many possible applications, particularly in the understanding and management of various pathologies, post-traumatic stress disorder being the most demonstrative in this respect.

Title: Le Programme 13-Novembre entre mémoire individuelle et mémoire collective. Abstract: Cet article a pour objectif de présenter l'évolution des travaux scientifiques sur la mémoire humaine de la fin du 19e siècle à aujourd'hui. Les travaux de psychologie expérimentale et de neuropsychologie ont d'abord dominé la scène scientifique. Des recherches en sciences humaines et sociales se sont mises en place dans l'entre-deux-guerres, mais sans réelle interaction avec celles menées en psychologie et en neurosciences. Cette clôture disciplinaire a persisté jusqu'à la fin du 20e siècle. Un véritable tournant social s'est opéré depuis les années 2000 avec comme volonté d'étudier et de comprendre les interactions entre mémoires individuelles et mémoires collectives. Dans cet article, les auteurs plaident pour l'émergence de « sciences de la mémoire ¼ fondées sur la dialectique et la transdisciplinarité. Ils s'appuient sur le Programme 13-Novembre, emblématique de cette évolution. Sa genèse, son architecture d'ensemble et plusieurs de ses composantes sont présentées ici ainsi que quelques résultats déjà publiés. Outre leur portée théorique, ces travaux rendent possibles de nombreuses applications, en particulier dans la compréhension et la prise en charge de différentes pathologies, le trouble de stress post-traumatique étant la plus démonstrative à cet égard.

[Memory alterations in post-traumatic stress disorder]. / Les altérations de la mémoire dans le trouble de stress post-traumatique.

Post-Traumatic Stress Disorder (PTSD) is a disorder that develops following the experience of a highly stressful event, which involves a confrontation with death or the threat of death, serious injury or sexual violence. It is characterized by symptoms such as intrusions, avoidance and hypervigilance. According to the literature, PTSD is associated with an imbalance between a privileged memorization of the emotional and sensory aspects of the traumatic event and a failure to memorize the contextual aspects. That is why PTSD is now considered a memory disorder whose effects extend to several components. In this review article, we focus on how PTSD affects long-term memory. The first part describes the long-term effects of PTSD on episodic memory with emphasis on the difficulties in encoding certain elements of the traumatic event and their consequences. These difficulties may be manifested in the narration of the trauma, with a discourse of the traumatic event lacking in contextual details. They may also lead to reliving and generalizing the fear to other contexts, whether they are related to the trauma or not. The second part of the article discusses how PTSD affects autobiographical memory and has consequences for the construction of identity and the perception of the past, present and future of people with this disorder. Autobiographical memory, which plays a key role in the storage of past personal memories as well as in identity formation, shows several forms of disruption induced by PTSD. First, a decrease in contextual details associated with memories of the personal past is observed, meaning that people with PTSD tend to remember their past experiences less accurately. Second, a propensity to project the future in a more negative and unpredictable manner is evidenced, related to a feeling of uncertainty about the future in PTSD suffering individuals. Finally, alterations in the encoding of present events due to the disruptive effects of post-traumatic stress symptoms during the encoding process are also identified.

Title: Les altérations de la mémoire dans le trouble de stress post-traumatique. Abstract: Le Trouble de Stress Post-Traumatique (TSPT) est une pathologie qui se développe chez une personne qui a fait l'expérience d'un événement hautement stressant impliquant une confrontation à la mort ou à une menace de mort, à une blessure grave ou à des violences sexuelles. Ce trouble se caractérise par plusieurs symptômes dont les intrusions, l'évitement et l'hypervigilance. Le TSPT est associé à un déséquilibre entre une mémorisation exacerbée des aspects émotionnels et sensoriels de l'événement traumatique et un défaut de mémorisation des aspects contextuels. En conséquence, le TSPT est aujourd'hui considéré comme un trouble de la mémoire dont les retentissements s'étendent à plusieurs de ses composantes. Cet article expose les conséquences du TSPT sur la mémoire à long terme et met la focale sur deux mécanismes : l'encodage partiel de l'événement traumatique en mémoire épisodique et l'influence de cette expérience traumatique sur les souvenirs personnels en mémoire autobiographique. L'article aborde en première partie les difficultés d'encodage de certains éléments de l'événement traumatique et leurs conséquences, comprenant les reviviscences ainsi que la persistance et la généralisation de la peur à d'autres contextes plus ou moins liés à l'événement traumatique. La deuxième partie aborde la façon dont le trouble affecte la mémoire autobiographique et l'identité en occasionnant une réduction de la précision des événements du passé, des altérations de la capacité à se projeter dans des événements futurs et un encodage incomplet de nouveaux événements.

[The dynamic brain-network model of PTSD]. / Les sciences des réseaux appliquées à l'étude du Trouble de Stress Post-Traumatique.

The brain is a highly complex system whose functioning is critical for our interaction with the world. Neural elements, from single cells to brain systems, constantly fluctuate in their dynamics, accompanying the plethora of possible exchanges between our environment and ourselves. However, sometimes things go awry. An unfortunate example is post-traumatic stress disorder (PTSD), a debilitating clinical condition that can appear after exposure to a threatening life event. In this work, using complexity as a framework, we aim to introduce the dynamic brain network model of PTSD. We hope this model will allow the generation of novel specific hypotheses concerning brain organization and dynamics in PTSD research. We first introduce how the network framework complements the localizationist approach centered in specific brain regions or subsets of brain regions, with a whole brain approach considering brain regions' dynamic relationships. Then, we review key concepts in network neuroscience, focusing on the importance of the network topology and dynamics to understand the organizational principles of the brain, that is, functional segregation and integration. In the third part, we apply this knowledge to describe the possible trajectories conducting a brain system to present PTSD alterations. Accordingly, we introduce the Dynamic Brain Network Model (DBNM) of PTSD, a concrete framework built on the network approach and resilience theory to study the transition of a brain network from state 1 (e.g., before the traumatic event) to state 2 (e.g., after the traumatic event). To conclude, we provide a summary of metrics for quantifying elements on the DBNM and its potential use in computational models of PTSD.

Title: Les sciences des réseaux appliquées à l'étude du Trouble de Stress Post-Traumatique. Abstract: Cet article expose la manière dont les sciences des réseaux peuvent contribuer à la compréhension du Trouble de Stress Post-Traumatique (TSPT). Nous soulignons l'intérêt de concevoir le cerveau comme un système complexe et dynamique pour affiner la description et la prédiction des réponses cérébrales après exposition à un évènement traumatique. À partir des modèles de résilience au stress et sous le prisme des sciences des réseaux, nous proposons une ligne temporelle du TSPT, partant des facteurs de résilience intrinsèques au réseau, présents avant l'évènement traumatique, jusqu'à la réponse cérébrale ayant lieu après l'évènement traumatique. Dans ce cadre, il est essentiel de considérer la topologie du cerveau et les dynamiques cérébrales dans des processus permettant d'utiliser ces facteurs de résilience. Ainsi, nous proposons un cadre concret, autorisant la formulation d'hypothèses explicites sur des aspects potentiellement critiques de l'organisation et des dynamiques des réseaux cérébraux impliqués dans le TSPT.

[The social traces of the trauma of the 13 November 2015 terrorist attacks: Five years and seven months after]. / Les traces sociales du traumatisme des attentats du 13 novembre 2015 : cinq ans et sept mois après.

The monitoring of how public opinion memorizes the terrorist attacks from 13th November 2015, and moreover the terrorist attacks since the early 2000s, provides new material for understanding the evolution over time and the mechanisms of the construction of collective memory. Data collected to date show that these attacks had a greater impact on the population than other tragic events that have occurred in recent history in France, or even a greater impact than other and much more recent attacks. In the long term, the precise memory of the factual aspects and the memories of the personal circumstances in which people learned about the events begin to vanish. While imprecision is gaining ground, collective memory now crystallizes on very significant and overdetermined markers such as emblematic places or locations such as the "Bataclan". As a matter of fact, this imprecision of memory goes hand-in-hand with a much stronger symbolic and emotional investment of the event as a whole and leads to an overestimation of the number of terrorists or victims. The special place given to the terrorist attacks of 13th November in the collective memory is due to the unprecedented number of victims, the fact that the attacks took place in the heart of the capital city, the reaction of the public authorities who declared a long lasting state of emergency, the discursive framing of the war on terrorism in all major media, and the feeling that the Islamist threat can kill indiscriminately without targeting specific categories of the population. The study also reveals the influence of value systems (political opinions, views of the republican model) and social characteristics of individuals on the way people memorize such experiences. It is part of a fundamentally multidisciplinary research around "Memory and trauma" that includes neuroscience, biological and clinical investigations.

Title: Les traces sociales du traumatisme des attentats du 13 novembre 2015 : cinq ans et sept mois après. Abstract: Le suivi de la mémoire des attentats du 13 novembre, et plus généralement des attaques terroristes depuis l'an 2000, auprès de la population générale offre un matériau inédit pour comprendre l'évolution dans le temps et la construction de la mémoire collective. L'étude montre que ces attaques ont davantage marqué la population que d'autres événements tragiques survenus dans l'Hexagone dans une période de temps proche, ou même que d'autres attentats beaucoup plus récents. Avec le temps, la mémorisation précise des faits et les souvenirs des circonstances dans lesquelles les personnes ont appris les faits s'érodent, et se concentrent notamment autour du lieu du Bataclan. Mais, cette imprécision fait place à un investissement symbolique plus fort, qui conduit notamment à une surestimation du nombre de terroristes ou de victimes. Les raisons de la place particulière dévolue aux attaques du 13 novembre dans la mémoire collective tiennent à la fois au nombre inégalé de victimes, à l'attaque de lieux situés dans la capitale, à la réaction des pouvoirs publics qui instaurent l'état d'urgence, au cadrage discursif de la guerre contre le terrorisme amplifié par les médias télévisuels et au sentiment que la menace islamiste peut tuer aveuglément sans viser des catégories précises de population. L'étude met également à jour l'influence des systèmes de valeur (couleur politique, regard sur le modèle républicain) et des caractéristiques sociales des individus sur la mémoire. Elle s'inscrit dans une recherche fondamentalement pluridisciplinaire autour de la « Mémoire et traumatisme ¼ intégrant des travaux en biologie, neurosciences et médecine.

The role of depressive symptoms in the interplay between aging and temporal processing.

Temporal processing, the ability to mentally represent and process the dynamical unfolding of events over time, is a fundamental feature of cognition that evolves with advancing age. Aging has indeed been associated with slower and more variable performance in timing tasks. However, the role of depressive symptoms in age-related changes in temporal processing remains to be investigated. Therefore, the present work aims to shed light on the link between temporal processing and depressive symptoms, which are frequent with advancing age. We relied on the multicentric "Blursday Project" database, providing measures of temporal processing together with questionnaires investigating psychological wellbeing. Results reveal that aging influences several timing abilities, from the reproduction of short time intervals to verbal estimations of longer temporal distances. Furthermore, the slowing down of felt passage of time regarding the last few days with age was fully mediated by the intensity of depressive symptoms. Overall, these findings suggest that depressive symptoms may play a pivotal role in age-related temporal processing changes.

Disruption in normal correlational patterns of metabolic networks in the limbic circuit during transient global amnesia.

Transient global amnesia is characterized by the sudden apparition of severe episodic amnesia, mainly anterograde, associated with emotional changes. Even though the symptoms are stereotyped, cerebral mechanism underlying transient global amnesia remains unexplained and previous studies using positron emission tomography do not show any clear results or consensus on cerebral regions impacted during transient global amnesia. This study included a group of 10 transient global amnesic patients who underwent 18F-fluorodeoxyglucose positron emission tomography during the acute or recovery phase of the episode and 10 paired healthy controls. Episodic memory was evaluated with the encoding-storage-retrieval paradigm and a story recall test of the Wechsler's memory scale and anxiety was assessed with the Spielberger scale. We used statistical parametric mapping to identify modifications of whole-brain metabolism. Regarding hypometabolism, there was no brain region systematically affected in all transient global amnesic patients and the comparison between amnesic patients and controls did not show any significant differences. To better understand the specific implication of the limbic circuit in the pathophysiology of transient global amnesia, we then conducted a correlational analysis that included regions of this network. Our findings showed that in healthy controls, regions of the limbic circuit seem to operate in a synchronized way with all regions being highly correlated to each other. On the opposite, in transient global amnesic patients, we observed a clear disruption of this normal correlational patterns between regions with the medial temporal lobe (the hippocampus, parahippocampal gyrus and amygdala) included in one cluster and the orbitofrontal cortex, anterior and posterior cingulate gyrus and thalamus gathered in the other one. Given the individual variability in the time course of transient global amnesia, the direct comparison between a group of patients and controls does not seem to favour the identification of subtle and transient alterations in regional metabolism. The involvement of an extended network, such as the limbic circuit, seems more likely to explain the symptoms of patients. Indeed, the synchronization of regions within the limbic circuit seems to be altered during transient global amnesia, which could explain the amnesia and anxiety observed in transient global amnesic patients. The present study thus deepens our understanding of the mechanisms underlying not only amnesia but also the emotional component of transient global amnesia by considering it as a disruption in the normal correlational patterns within the limbic circuit.

Brain correlates of declarative memory atypicalities in autism: a systematic review of functional neuroimaging findings.

The long-described atypicalities of memory functioning experienced by people with autism have major implications for daily living, academic learning, as well as cognitive remediation. Though behavioral studies have identified a robust profile of memory strengths and weaknesses in autism spectrum disorder (ASD), few works have attempted to establish a synthesis concerning their neural bases. In this systematic review of functional neuroimaging studies, we highlight functional brain asymmetries in three anatomical planes during memory processing between individuals with ASD and typical development. These asymmetries consist of greater activity of the left hemisphere than the right in ASD participants, of posterior brain regions-including hippocampus-rather than anterior ones, and presumably of the ventral (occipito-temporal) streams rather than the dorsal (occipito-parietal) ones. These functional alterations may be linked to atypical memory processes in ASD, including the pre-eminence of verbal over spatial information, impaired active maintenance in working memory, and preserved relational memory despite poor context processing in episodic memory.

Alterations in resting-state functional connectivity associated to the age-related decline in time-based prospective memory.

Time-based prospective memory (TBPM) is defined as the ability to remember to perform intended actions at a specific time in the future. TBPM is impaired in aging, and this decline has been associated with white-matter alterations within the superior fronto-occipital fasciculus. In the present study, we used resting-state functional magnetic resonance imaging from 22 healthy young (26 ± 5.2 years) and 23 older (63 ± 6.1 years) participants to investigate how age-related alterations in resting-state functional connectivity are related to TBPM performance, and whether these alterations are associated with the white-matter disruptions we have previously observed with diffusion tensor imaging. Whole-brain analyses revealed lower resting-state functional connectivity in older participants compared with younger ones, which in turn correlated with TBPM performance. These correlations were mainly located in the salience network and the parietal part of the frontoparietal network. Our findings suggest that resting-state functional connectivity alterations contribute to the age-related decline in TBPM.

Intact memory storage but impaired retrieval in visual memory in autism: New insights from an electrophysiological study.

In a recent study on visual episodic memory (Desaunay, Clochon, et al., 2020), we have shown event-related potentials (ERPs) differences associated with priming (150-300 msec), familiarity (350-470 msec), and recollection (600-700 msec), in young people with autism spectrum disorders (ASD) compared with typical development (TD). To go further into the study of the processes of storage and retrieval of the memory trace, we re-analyzed Desaunay, Clochon, et al's data using time-frequency analysis, that is, event-related synchronization and desynchronization (ERS/ERD). This allows a decomposition of the spectral power within frequency bands associated with these ERPs. We focused both on the same time windows and the same regions of interest as previously published. We mainly identified, in ASD compared with TD, reduced ERS in low-frequencies (delta, theta) in early time-windows, and non-significant differences in ERD in higher frequencies (alpha, beta1) in all time-windows. Reduced ERS during recognition confirmed previously reported diminution of priming effects and difficulties in manipulation and retrieval of both semantic and episodic information. Conversely, preserved ERD corroborates a preservation of memory storage processes. These observations are consistent with a cognitive model of memory in ASD, that suggests difficulties in cognitive operations or executive demand at retrieval, subsequent to successful long-term storage of information. LAY SUMMARY: We assessed the EEG synchronization and desynchronization, during visual episodic recognition. We observed, in youth with Autism, reduced synchronization in low-frequencies (delta, theta), suggesting reduced access to and manipulation of long-term stored information. By contrast, non-significant differences in desynchronization at higher frequencies (alpha, beta frequency bands), that support long-term stored semantic and episodic information, suggested preserved memory traces.

[Neuropsychology of memory]. / Neuropsychologie de la mémoire.

NEUROPSYCHOLOGY OF MEMORY. In neuropsychology, memory is shown as a complex function composed of several memory systems. Five memory systems are proposed: working memory (or short term memory), episodic memory, semantic memory, perceptive memory, and procedural memory. These different systems of individual memory interact with collective memories.

NEUROPSYCHOLOGIE DE LA MÉMOIRE. En neuropsychologie, la mémoire est conçue comme une fonction complexe formée de plusieurs systèmes. Cinq grands systèmes sont le plus souvent différenciés : la mémoire de travail (ou mémoire à court terme), la mémoire épisodique, la mémoire sémantique, la mémoire perceptive et la mémoire procédurale. Ces différentes entités, composant la mémoire individuelle, interagissent avec les mémoires collectives.

Mathematical modeling of human memory.

The mathematical study of human memory is still an open challenge. Cognitive psychology and neuroscience have given a big contribution to understand how the human memory is structured and works. Cognitive psychologists developed experimental paradigms, conceived quantitative measures of performance in memory tasks for both healthy people and patients with memory disorders, but in terms of mathematical modeling human memory there is still a lot to do. There are many ways to mathematically model human memory, for example, by using mathematical analysis, linear algebra, statistics, and artificial neural networks. The aim of this study is to provide the reader with a description of some prominent models, involving mathematical analysis and linear algebra, designed to describe how memory works by predicting the results of psychological experiments. We have ordered the models from a chronological point of view and, for each model, we have emphasized what are, in our opinion, the strong and weak points. We are aware that this study covers just a part of human memory modeling as well as that we have made a personal selection, which is arguable. Nevertheless, our hope is to help scientists to modeling human memory and its diseases.

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 later forgetting. Unwanted memories require the reflexive orienting of attention and access to consciousness to be suppressed effectively by inhibitory control.