Dans les dernières années, les études sur les maladies neurodégénératives telles que la maladie d’Alzheimer (MA) et la maladie de Parkinson sans démence (MP) et avec démence (MPD) ont été nombreuses, mais la différenciation de ces patients sur la base de leur profil cognitif doit être encore améliorée. Effectivement, l’évaluation clinique peut s’avérer difficile en raison du peu de spécificité dans la présentation de leurs déficits neuropsychologiques. Ceci s’explique par la variabilité et le chevauchement des processus cliniques et pathologiques affectant essentiellement les mêmes régions/fonctions, soit celles liées aux lobes temporaux médians (LTM)/Mémoire (fonction LTM/Mémoire) et aux lobes frontaux (LF)/Fonctions exécutives (fonction LF/Exécutive). Toutefois, il existerait une distinction critique au niveau de l’intégrité relative de ces fonctions dans ces maladies neurodégénératives, ce qui permettrait d’identifier des déficits cognitifs spécifiques à la MA, la MP et la MPD. La présente thèse s’inscrit dans cette volonté de caractériser les profils cognitifs propres à la MA, la MP et la MPD, plus précisément par l’étude novatrice de la mémoire de source et des faux souvenirs. Les quatre chapitres qui composent cette thèse servent donc à documenter la nature de ces mécanismes mnésiques, leurs patrons de performance spécifiques dans la MA, la MP et la MPD, et leur sensibilité aux atteintes des fonctions LTM/Mémoire et LF/Exécutive. Ainsi, le Chapitre I démontre la pertinence d’étudier la mémoire de source et les faux souvenirs dans la MA, la MP et la MPD, en décrivant leurs interactions avec les fonctions LTM/Mémoire et LF/Exécutive, toutes les deux atteintes dans ces maladies. Le Chapitre II, présenté sous forme d’article, révèle des déficits en mémoire de source chez des patients MP, mais seulement dans l’une des tâches employées. Également, malgré des atteintes des fonctions LF/Exécutive et LTM/Mémoire, il est démontré que seule la fonction LTM/Mémoire est liée à l’altération de la mémoire de source chez les patients MP. Le Chapitre III, également sous forme d’article, illustre un taux anormal de faux souvenirs chez des patients MA, tandis que chez des patients MP et MPD, il est démontré qu’ils ont un taux de faux souvenirs comparable à celui des participants contrôles. Il est également rapporté que malgré l’atteinte de la fonction LF/Exécutive chez les patients MA, MP et MPD, elle est seulement liée à l’augmentation des faux souvenirs chez les patients MA. Finalement, dans le dernier Chapitre (IV), les résultats obtenus sont discutés dans leur ensemble à la lumière des prédictions et connaissances actuelles, tout en identifiant les limites afin d’orienter les perspectives de recherche. / In the last years, there have been numerous studies on neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease without dementia (PD) and with dementia (PDD), but differentiation of these patients based on their cognitive profile remains to be better understood. Indeed, clinical diagnosis remains difficult given that their neuropsychological deficits lack specificity. An explanation lies in the variability and overlap in terms of both clinical and neuroanatomical signs affecting similar brain regions/functions, which are those linked to medial temporal lobes (MTL)/Memory (MTL/Memory function) and to frontal lobes (FL)/Executive functions (FL/Executive function). However, a critical distinction lies in the relative integrity of both functions across AD, PD and PDD patients, which likely allows the capture of diagnosis-specific patterns of performance. This thesis addresses the need to describe the cognitive deficits more precisely by using novel measures of source memory and false memory. In the next four chapters of this thesis, the mechanisms underlying these forms of memory will be described as well as specific patterns of performance in AD, PD and PDD in source memory and false memory and their link to MTL/Memory and FL/Executive dysfunction. In Chapter I, the relevance of studying source memory and false memory in AD, PD and PDD, is explained by describing their interaction with MTL/Memory and FL/Executive functions, both impaired in these diseases. In Chapter II, a first study found source memory deficits in PD patients but only on one of the tasks that were used. Also, despite impaired MTL/Memory and FL/Executive functions, only MTL/Memory function is linked to impaired source memory in PD. In Chapter III, a second study found abnormal false memory rates in AD patients while in PD and PDD patients, false memory rates are comparable to those of healthy controls. It is also reported that despite impaired FL/Executive functions in AD, PD and PDD patients FL/Executive function is only linked to an increase in false memory rates in AD patients. Finally, in the last Chapter (IV), results of this thesis as a whole are discussed in light of predictions and the current literature and future research perspectives are discussed.

There is an age-shift in neurotypical children: younger children tend to remember information in a verbatim manner so they store item-specific surface characteristics; between nine and ten children engage in gist recall where they store meanings of presented information. The aim of the present study was to explore false memory in children with Autistic Spectrum Disorder (ASD), as some research suggests that they develop gist recall at a later age than neurotypical children. We are also interested in the role of working memory. One approach to understanding false memory creation is activation-monitoring (AM) theory. Working memory can play a role during both the activation (encoding) phase, as well as during the monitoring retrieval phase. When working memory is overloaded or suboptimal, source monitoring is compromised at the encoding phase. In this study, we tested high-functioning children with ASD on working memory capacity. In addition, simple sentences were presented to be recalled, each one followed by a short word list that contained a thematically related distractor item. If a child used gist memory to recall the sentence, they would likely substitute the target (e.g., rabbit) word with the distractor (e.g., bunny). However, if they depended on verbatim recall, the distractor would not affect sentence recall performance. Children with lower working memory scores were more likely to incorrect answers to gist questions than those with high working memory. These findings have important implications for everyday social functioning. Though debatable, working memory impairments may encourage false memories in children with ASD.

- / Doctorat en Sciences Psychologiques et de l'éducation / info:eu-repo/semantics/nonPublished

Recently, cognitive psychologists have focused their research on the survival aspects of human memory, showing advantages for remembering information encoded for adaptive qualities. When participants rated words related to survival relevance (stranded in grasslands), Nairne et al. (2007) and others found survival processing’s retention superior to many semantic encoding techniques, however, we questioned the global application of survival processing. In the present adaptive memory experiment we used the thematic word list paradigm pioneered by Deese, Rodeiger and McDermott, allowing us to measure false recall of critical items from sets of word lists. To investigate recall differences based on the material type encoded, we separated recalled material into two categories: survival and non-survival. Because arousal can influence memory performance, we extended research on adaptive memory to include social arousal induced by videotaping participants during study and recall tasks. Videotaping subjects has been shown to induce arousal levels similar to those when being observed, and may parallel arousal experienced in survival scenarios. Overall, recall was lower for survival processing. Survival-relevant information was more accurately remembered, and was not hindered by camera presence, unlike non-survival information. Additionally, false memories were higher under videotaped conditions. While our results did not support Nairne and colleagues, our findings may support the development of evolved brain mechanisms. The current findings are discussed with an emphasis on contemporary high arousal situations that may influence the activation of adaptive memories. We join a growing set of literature that questions the overall benefits of survival processing.

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