Collective memories and social roles: the case of the Paris terrorist attacks of 13 November 2015.

The present study was based on empirical data collected during the first phase (2016) of Study 1000, part of the 13-November Program: a corpus of 934 individual interviews conducted 6-11 months after the events. To process this empirical material, the authors used integrated TXM software, which provides several classic textometry tools. They mainly used the lexical specificity analysis tool, which statistically measures the irregularity of the word distribution according to the parts of the corpus. They also analyzed the concordances of certain very specific lexical forms. Analysis revealed the important influence of social roles on the construction of memories and narratives of this event. Application of textometry tools highlighted lexical fields specific to the different social roles played by the interviewees in this social drama, and showed that it was through these specific vocabularies that they remembered and recounted this extraordinary story. Social roles therefore influence the formation of memories both individual and collective, by modulating the way in which individuals select what to remember and what to forget. The article opens up several interesting avenues for future analyses, mainly a longitudinal perspective (including phases 2 and 3 of Study 1000) for the study of flashbulb memories and the gender issue to fine-tune the analysis of social roles.

Interdisciplinary approach to identify language markers for post-traumatic stress disorder using machine learning and deep learning.

Post-traumatic stress disorder (PTSD) lacks clear biomarkers in clinical practice. Language as a potential diagnostic biomarker for PTSD is investigated in this study. We analyze an original cohort of 148 individuals exposed to the November 13, 2015, terrorist attacks in Paris. The interviews, conducted 5-11 months after the event, include individuals from similar socioeconomic backgrounds exposed to the same incident, responding to identical questions and using uniform PTSD measures. Using this dataset to collect nuanced insights that might be clinically relevant, we propose a three-step interdisciplinary methodology that integrates expertise from psychiatry, linguistics, and the Natural Language Processing (NLP) community to examine the relationship between language and PTSD. The first step assesses a clinical psychiatrist's ability to diagnose PTSD using interview transcription alone. The second step uses statistical analysis and machine learning models to create language features based on psycholinguistic hypotheses and evaluate their predictive strength. The third step is the application of a hypothesis-free deep learning approach to the classification of PTSD in our cohort. Results show that the clinical psychiatrist achieved a diagnosis of PTSD with an AUC of 0.72. This is comparable to a gold standard questionnaire (Area Under Curve (AUC) ≈ 0.80). The machine learning model achieved a diagnostic AUC of 0.69. The deep learning approach achieved an AUC of 0.64. An examination of model error informs our discussion. Importantly, the study controls for confounding factors, establishes associations between language and DSM-5 subsymptoms, and integrates automated methods with qualitative analysis. This study provides a direct and methodologically robust description of the relationship between PTSD and language. Our work lays the groundwork for advancing early and accurate diagnosis and using linguistic markers to assess the effectiveness of pharmacological treatments and psychotherapies.

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.

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.

[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.

[Memories of the 13-November 2015 terrorist attacks: what discourse analysis can teach us]. / Mémoires des attentats terroristes du 13-Novembre 2015 : ce que peut nous apprendre l'analyse de discours.

The Programme 13-Novembre aims to analyze the individual and collective memory of the terrorist attacks of November 13, 2015. At its heart is the Étude 1000, which is to gather the same 1000 people in audiovisual interviews four times in 10 years. Having the transcripts at our disposal, we choose here to show the importance of discourse analysis by recalling its theoretical foundations, to present one of the tools allowing this statistical analysis, the Correspondence Factor Analysis, and to use it to analyze the sub-corpus of interviews conducted at a distance from the Paris events, with 76 inhabitants of the Metz region. Crossing these volunteers with the words they use, we see that two variables clearly stand out that oppose the vocabularies, the gender variable and the age variable.

Title: Mémoires des attentats terroristes du 13-Novembre 2015 : ce que peut nous apprendre l'analyse de discours. Abstract: Le Programme 13-Novembre vise à analyser la mémoire individuelle et collective des attentats terroristes du 13 novembre 2015. Au cœur se trouve l'Étude 1000 qui doit recueillir, à 4 reprises en 10 ans, les témoignages des mêmes 1000 personnes dans des entretiens audiovisuels. Disposant des transcriptions, nous choisissons ici de montrer l'importance de l'analyse de discours en rappelant ses fondements théoriques, de présenter l'un des outils permettant cette analyse statistique, l'Analyse Factorielle des Correspondances, et de l'utiliser pour analyser le sous-corpus des entretiens réalisés à distance des événements parisiens, auprès de 76 habitants de la région de Metz. Croisant ces volontaires avec les mots qu'ils utilisent, on constate que deux variables ressortent clairement qui opposent les vocabulaires, la variable du genre et la variable de l'âge.

Toward new memory sciences: The Programme 13-Novembre.

Studies devoted to individual and collective memory have evolved in a compartmentalized way for more than a century. 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. Since the beginning of the years 2000, the social turn in life sciences and, more rarely, the opening up of sociologists and historians to the life sciences have tended to bring these hitherto compartmentalized currents together. 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. The main objective of this program is to better understand the links between individual and collective memory in the construction of these memories related to this traumatic event. This research is fundamentally transdisciplinary-i.e., developed by researchers from different disciplines-and longitudinal over 12 years to understand the evolution of memories over time. Our studies focus on people who were closest to the traumatic event-and likely to develop posttraumatic stress disorder-and on those who were further away but who are more representative of the general population. We present some of the results, derived from data collected in studies of the program that feed our advocacy for new memory sciences.

Multi-Data Integration Towards a Global Understanding of the Neurological Impact of Human Brain Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

As the COVID-19 pandemic continues to unfold, numerous neurological symptoms emerge. The literature reports more and more manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) related to headache, dizziness, impaired consciousness, cognitive impairment, and motor disorders. Moreover, the infection of SARS-CoV-2 may have a durable neurological impact. ACE2/TMPRSS2 is the main entry point into cells for some strains of coronaviruses (CoVs), including SARS-CoV-2, which uses it to target the central nervous system (CNS). The aim of this study was to characterize the scope of the potential complex impact of a SARS-CoV-2 infection in the brain. It concerns different scales: the topographic, cognitive, sensorimotor, and genetic one. We investigated which cognitive and sensorimotor functions are associated with the brain regions where ACE2/TMPRSS2 is overexpressed, hypothesising that they might be particularly affected by the infection. Furthermore, overexpressed genes in these regions are likely to be impacted by COVID-19. This general understanding is crucial to establish the potential neurological manifestations of the infection. Data on mRNA expression levels of genes were provided by the Allen Institute for Brain Science (AIBS), and the localisation of brain functions by the LinkRbrain platform. The latter was also used to analyze the spatial overlap between ACE2/TMPRSS2 overexpression, and either function-specific brain activations or regional overexpression of other genes. The characterisation of these overexpressed genes was based on the GeneCards platform and the gene GSE164332 from the Gene Expression Omnibus database. We analysed the cognitive and sensorimotor functions whose role might be impaired, of which 88 have been categorised into seven groups: memory and recollection, motor function, pain, lucidity, emotion, sensory, and reward. Furthermore, we categorised the genes showing a significant increase in concentration of their mRNAs in the same regions where ACE2/TMPRSS2 mRNA levels are the highest. Eleven groups emerged from a bibliographical research: neurodegenerative disease, immunity, inflammation, olfactory receptor, cancer/apoptosis, executive function, senses, ischemia, motor function, myelination, and dependence. The results of this exploration could be in relation to the neurological symptoms of COVID-19. Furthermore, some genes from peripheral blood are already considered as biomarker of COVID-19. This method could generate new hypotheses to explore the neurological manifestations of COVID-19.

Altered predictive control during memory suppression in PTSD.

Aberrant predictions of future threat lead to maladaptive avoidance in individuals with post-traumatic stress disorder (PTSD). How this disruption in prediction influences the control of memory states orchestrated by the dorsolateral prefrontal cortex is unknown. We combined computational modeling and brain connectivity analyses to reveal how individuals exposed and nonexposed to the 2015 Paris terrorist attacks formed and controlled beliefs about future intrusive re-experiencing implemented in the laboratory during a memory suppression task. Exposed individuals with PTSD used beliefs excessively to control hippocampal activity during the task. When this predictive control failed, the prediction-error associated with unwanted intrusions was poorly downregulated by reactive mechanisms. This imbalance was linked to higher severity of avoidance symptoms, but not to general disturbances such as anxiety or negative affect. Conversely, trauma-exposed participants without PTSD and nonexposed individuals were able to optimally balance predictive and reactive control during the memory suppression task. These findings highlight a potential pathological mechanism occurring in individuals with PTSD rooted in the relationship between the brain's predictive and control mechanisms.

Avoidance behaviour generalizes to eye processing in posttraumatic stress disorder.

Background: Avoidance describes any action designed to prevent an uncomfortable situation or emotion from occurring. Although it is a common reaction to trauma, avoidance becomes problematic when it is the primary coping strategy, and plays a major role in the development and maintenance of posttraumatic stress disorder (PTSD). Avoidance in PTSD may generalize to non-harmful environmental cues that are perceived to be unsafe. Objective: We tested whether avoidance extends to social cues (i.e. emotional gazes) that are unrelated to trauma. Method: A total of 159 participants (103 who had been exposed to the 2015 Paris terrorist attacks and 56 who had not) performed a gaze-cueing task featuring sad, happy and neutral faces. Attention to the eye area was recorded using an eyetracker. Of the exposed participants, 52 had been diagnosed with PTSD (PTSD+) and 51 had not developed PTSD (PTSD-). As a result of the preprocessing stages, 52 PTSD+ (29 women), 50 PTSD- (20 women) and 53 nonexposed (31 women) participants were included in the final analyses. Results: PTSD+ participants looked at sad eyes for significantly less time than PTSD- and nonexposed individuals. This effect was negatively correlated with the intensity of avoidance symptoms. No difference was found for neutral and happy faces. Conclusions: These findings suggest that maladaptive avoidance in PTSD extends to social processing, in terms of eye contact and others' emotions that are unrelated to trauma. New therapeutic directions could include targeting sociocognitive deficits. Our findings open up new and indirect avenues for overcoming maladaptive avoidance behaviours by remediating eye processing.Trial registration: ClinicalTrials.gov identifier: NCT02810197. HIGHLIGHTS: Avoidance is a key symptom of posttraumatic stress disorder (PTSD).Avoidance is often viewed as limited to reminders linked to the trauma.Results show that attention to the eyes of sad faces is also affected by PTSD. This effect is correlated with avoidance symptoms in PTSD.

Antecedentes: La evitación describe cualquier acción diseñada para prevenir una situación o emoción desagradable. Aunque es una reacción común al trauma, la evitación se vuelve problemática cuando es la principal estrategia de afrontamiento, y desempeña un papel importante en el desarrollo y mantenimiento del trastorno de estrés postraumático (TEPT). La evitación en el TEPT puede generalizarse a señales ambientales no dañinas que se perciben como inseguras. Objetivo: Probamos si la evitación se extiende a las señales sociales (es decir, las miradas emocionales) que no están relacionadas con el trauma. Método: Un total de 159 participantes (103 que habían estado expuestos a los atentados terroristas de París del 2015 y 56 que no lo habían estado) realizaron una tarea de captación de miradas con rostros tristes, felices y neutros. La atención a la zona de los ojos se registró mediante un rastreador ocular. De los participantes expuestos, 52 habían sido diagnosticados con TEPT (TEPT+) y 51 no habían desarrollado TEPT (TEPT-). Resultados: Los participantes con TEPT+ miraron los ojos tristes durante un tiempo significativamente menor que los individuos con TEPT- y los no expuestos. Este efecto se correlacionó negativamente con la intensidad de los síntomas de evitación. No se encontraron diferencias para las caras neutras y felices Conclusiones: Estos hallazgos sugieren que la evitación desadaptativa en el TEPT se extiende al procesamiento social, en cuanto al contacto visual y las emociones de los demás que no están relacionadas con el trauma. Las nuevas direcciones terapéuticas podrían incluir centrarse en los déficits sociocognitivos. Nuestros hallazgos abren vías nuevas e indirectas para superar las conductas de evitación desadaptativas mediante la remediación del procesamiento ocular.

Changes over 10 years in the retelling of the flashbulb memories of the attack of 11 September 2001.

A flashbulb memory is a highly detailed and vivid autobiographical memory for the circumstances in which one first learned of a surprising, consequential and emotionally arousing event. How retelling of different features of a flashbulb memory changes over time is not totally understood. Moreover, little is known about how the emotional feeling experienced by individuals when they learned about the event modulates these changes. In this study, we explored changes over time in American individuals' retelling of their flashbulb memories of the terrorist attack of 11 September 2001. We conducted textual analysis of 824 testimonies collected from the same 206 individuals 1 week, 11, 25 and again 119 months after the attack. Results showed individuals were more likely to report temporal and emotional details in their retelling early after the event and spatial details in their long-term retelling. In addition, the intensity of emotions felt upon hearing the news about the attack influenced how individuals reported their flashbulb memories over time. Overall, this study provides further support for theories suggesting different rates of forgetting for different canonical features of emotional arousal events.

Variations in response to trauma and hippocampal subfield changes.

Models of posttraumatic stress disorder (PTSD) suggest that the hippocampus is key to the persistence of traumatic memory. Yet very little is known about the precise changes that take place in this structure, nor their relation with PTSD symptoms. Previous studies have mostly used magnetic resonance imaging (MRI) at low resolutions, making it impossible to identify sensitive anatomical landmarks, or compared groups often unequally matched in terms of traumatic exposure. The present cross-sectional study included 92 individuals who had all been exposed to the terrorist attacks in Paris on November 13, 2015 (53 of whom subsequently developed PTSD) and 56 individuals who had not been exposed. Hippocampal subfield volumes were estimated using cross-validated automatic segmentation of high-resolution MRI images. Results revealed changes in CA1 and CA2-3/dentate gyrus (DG) volumes in individuals with PTSD, but not in resilient (i.e., exposed but without PTSD) individuals, after controlling for potential nuisance variables such as previous traumatic exposure and substance abuse. In line with current models of hippocampal subfield functions, CA1 changes were linked to the uncontrollable re-experiencing of intrusive memories, while CA2-3/DG changes, potentially exacerbated by comorbid depression, fostered the overgeneralization of fear linked to avoidance and hypervigilance behaviors. Additional analyses revealed that CA1 integrity was linked to optimum functioning of the memory control network in resilient individuals. These findings shed new light on potential pathophysiological mechanisms in the hippocampus subtending the development of PTSD and the failure to recover from trauma.

Long-term modulation of cardiac activity induced by inhibitory control over emotional memories.

Efforts to exclude past experiences from conscious awareness can lead to forgetting. Memory suppression is central to affective disorders, but we still do not really know whether emotions, including their physiological causes, are also impacted by this process in normal functioning individuals. In two studies, we measured the after-effects of suppressing negative memories on cardiac response in healthy participants. Results of Study 1 revealed that efficient control of memories was associated with long-term inhibition of the cardiac deceleration that is normally induced by disgusting stimuli. Attempts to suppress sad memories, by contrast, aggravated the cardiac response, an effect that was closely related to the inability to forget this specific material. In Study 2, electroencephalography revealed a reduction in power in the theta (3-8 Hz), alpha (8-12 Hz) and low-beta (13-20 Hz) bands during the suppression of unwanted memories, compared with their voluntary recall. Interestingly, however, the reduction of power in the theta frequency band during memory control was related to a subsequent inhibition of the cardiac response. These results provide a neurophysiological basis for the influence of memory control mechanisms on the cardiac system, opening up new avenues and questions for treating intrusive memories using motivated forgetting.

Resilience after trauma: The role of memory suppression.

In the aftermath of trauma, little is known about why the unwanted and unbidden recollection of traumatic memories persists in some individuals but not others. We implemented neutral and inoffensive intrusive memories in the laboratory in a group of 102 individuals exposed to the 2015 Paris terrorist attacks and 73 nonexposed individuals, who were not in Paris during the attacks. While reexperiencing these intrusive memories, nonexposed individuals and exposed individuals without posttraumatic stress disorder (PTSD) could adaptively suppress memory activity, but exposed individuals with PTSD could not. These findings suggest that the capacity to suppress memory is central to positive posttraumatic adaptation. A generalized disruption of the memory control system could explain the maladaptive and unsuccessful suppression attempts often seen in PTSD, and this disruption should be targeted by specific treatments.

Eye-tracking and learning experience: gaze trajectories to better understand the behavior of memorial visitors.

Eye-tracking technology is increasingly introduced in museums to assess their role in learning and knowledge transfer. However, their use provide limited quantitative and/or qualitative measures such as viewing time and/or gaze trajectory on an isolated object or image (Region of Interest "ROI").The aim of this work is to evaluate the potential of the mobile eye-tracking to quantify the students' experience and behaviors through their visit of the "Genocide and mass violence" area of the Caen memorial. In this study, we collected eye-tracking data from 17 students during their visit to the memorial. In addition, all visitors filled out a questionnaire before the visit, and a focus group was conducted before and after the visit. The first results of this study allowed us to analyze the viewing time spent by each visitor in front of 19-selected ROIs, and some of their specific sub-parts. The other important result was the reconstruction of the gaze trajectory through these ROIs. Our global trajectory approach allowed to complete the information obtained from an isolated ROI, and to identify some behaviors such as avoidance. Clustering analysis revealed some typical trajectories performed by specific sub-groups. The eye-tracking results were consolidated by the participants' answers during the focus group.

Collective memory shapes the organization of individual memories in the medial prefrontal cortex.

It has long been hypothesized that individual recollection fits collective memory. To look for a collective schema, we analysed the content of 30 years of media coverage of World War II on French national television. We recorded human brain activity using functional magnetic resonance imaging as participants recalled World War II displays at the Caen Memorial Museum following an initial tour. We focused on the medial prefrontal cortex, a key region for social cognition and memory schemas. The organization of individual memories captured using the distribution of the functional magnetic resonance imaging signal in the dorsal part of the medial prefrontal cortex was more accurately predicted by the structure of the collective schema than by various control models of contextual or semantic memory. Collective memory, which exists outside and beyond individuals, can also organize individual memories and constitutes a common mental model that connects people's memories across time and space.