Théophile Bieth

REM sleep is considered a ‘hyperassociative’ state enhancing the connections between weakly related concepts, thereby facilitating memory restructuring — a critical process proposed in creative problem-solving. We empirically explore this hypothesis by testing participants on a riddle before and after a 90-minute incubation period including rapid eye movement (REM) sleep, only non-REM sleep, or wakefulness. We quantified memory restructuring by computing differences in problem-related semantic memory network (SemNets) properties between pre- and post-incubation. For each sleep stage, we extracted fine-grained electroencephalogram (EEG) measures linked to cognitive richness. REM sleep, compared to wake, reshaped the dominant problem representation by combining semantically remote concepts in memory and reducing strong but solution-irrelevant associations of ideas. Such REM sleep-related restructuring was associated with EEG measures indexing a richer cognitive state. While REM drove memory restructuring, it alone did not boost problem-solving success, suggesting that more extensive restructuring or additional processes are necessary for creative breakthroughs.

UNSTRUCTURED Apathy is one of the most prevalent and disabling neuropsychiatric symptoms in dementia, characterized by reduced motivation and diminished goal-directed activity, with strong impacts for both the person living with dementia and their caregivers. Despite its prevalence, its assessment remains challenging, as it relies largely on subjective self-reports and scales. In response, objective and quantifiable biomarkers derived from digital health technologies have emerged as a promising approach. The ECOCAPTURE program at the Paris Brain Institute (ICM) has developed ecological paradigms to identify behavioral and physiological markers of apathy, highlighting a core “exploration deficit” associated with this symptom. The present paper describes ECOCAPTURE@HOME(EYE), the eye-tracking and neuroimaging component of the broader ECOCAPTURE@HOME-V2 protocol. This study integrates eye-tracking across laboratory-based tasks and an ecological at-home setting to characterize oculomotor dynamics and visual exploration patterns in behavioral variant frontotemporal dementia (bvFTD), Alzheimer’s disease (AD), and healthy controls. These measures will be combined with clinical assessments of apathy and structural and functional MRI to investigate the behavioral and neural mechanisms underlying this symptom. This protocol aims to identify objective, ecologically valid, and clinically meaningful ocular markers of apathy, and to refine its digital phenotype within a multimodal framework. More broadly, it seeks to support the development of improved assessment tools and contribute to data-driven, individualized approaches in dementia care.

Résoudre des problèmes fait partie de notre quotidien. Cela nous permet de faire face à des situations nouvelles, de surmonter des obstacles et d’exprimer notre créativité. Pourtant, les mécanismes neurocognitifs et modulateurs de la résolution de problèmes sont peu étudiés et non élucidés. La restructuration est un mécanisme avancé pour expliquer comment un individu résout un problème. Elle fait référence aux processus permettant de modifier la représentation d’un problème par la création de nouvelles associations d’idées éloignées en mémoire. Elle est souvent associée à l’expérience d’un « Eureka ! ». De ce fait, la restructuration est étroitement liée aux théories cognitives de la créativité (i.e., la capacité à générer des idées nouvelles, originales et adaptées) et du raisonnement par analogie (i.e., établir des liens entre des éléments éloignés du fait de la détection de similarités structurelles).Bien que la théorie de la restructuration soit intuitive, ses preuves empiriques sont rares et non satisfaisantes, notamment en raison des difficultés méthodologiques pour la capturer et la mesurer. Nous avons développé un nouvel outil basé sur la construction de réseaux sémantiques qui permet de refléter la manière dont un individu se représente un problème. Ces réseaux sémantiques sont composés de nœuds correspondant à des mots en rapport avec un problème, connectés par des liens représentant la distance sémantique entre chaque paire de nœuds. En évaluant les changements d’organisation de ces réseaux au cours de la résolution d’un problème, nous pouvons capturer et mesurer des changements représentationnels du problème (i.e., la restructuration). Dans cette thèse, nous avons abordé la question des mécanismes neurocognitifs permettant ou facilitant la résolution de problèmes à travers la théorie de la restructuration via les réseaux sémantiques. Dans la première partie de cette thèse, nous avons montré que les processus de restructurations étaient impliqués dans la résolution de problèmes créatifs et analogues. En particulier, nous avons montré que les changements qui s’opéraient dans les réseaux sémantiques au niveau de nœuds et liens évalués comme pertinent pour résoudre un problème étaient associés à sa résolution et celle d’un problème analogue. Ces résultats démontrent le lien étroit existant entre restructuration et résolution de problèmes et font discuter son rôle mécanistique. Dans la deuxième partie de cette thèse, nous avons exploré les corrélats neuronaux associés à deux mécanismes impliqués dans la restructuration : l’effet de l’éloignement sémantique dans la création d’associations d’idées et celui d’une résolution avec Eurêka. Nous avons montré que ces processus présentaient des signatures électrophysiologiques spécifiques offrant de nouvelles perspectives dans l’étude des bases neurales de la restructuration et de la résolution de problèmes. Enfin, dans la dernière partie, nous avons exploré le sommeil paradoxal comme facteur modulateur de la restructuration et de la résolution de problèmes. Nous avons démontré que le sommeil paradoxal était associé à un état mental d’hyper-associativité permettant de faciliter la réorganisation de nos associations d’idées relatives à un problème, comme plusieurs modèles théoriques le suggéraient. Cependant, trouver la solution au problème n’était pas facilité par le sommeil, faisant discuter sa place dans la résolution de problèmes. Pour conclure, cette thèse offre de nouveaux résultats permettant de mieux comprendre la place de la restructuration dans la résolution de problèmes à plusieurs niveaux mécanistiques. Notre outil de mesure de restructuration ouvre la voie à de nombreuses perspectives d’études afin de préciser les mécanismes de résolution de problèmes, de déterminer ses corrélats neuronaux et d’étudier d’autres facteurs pouvant les moduler, avec un impact attendu positif tant à l’échelle individuelle que sociétale.

Creative thinking is a fundamental aspect of human cognition, enabling the production of novel and useful ideas. It is hypothesized to emerge from the binding and reconfiguration of existing knowledge, through the generation of remote semantic associations and their combination in original and meaningful ways, respectively supported by the default mode (DMN) and executive control (ECN) networks. At the crossroads of these two networks, the rostral prefrontal cortex (PFC) is proposed as a key hub for DMN-ECN interactions, possibly supporting the interplay between generative and combinatory creative processes. However, the specific contributions of its medial and lateral subdivisions to creativity remain unclear. In this study, we aimed to characterize the involvement of the rostral PFC in creative cognition through the lens of behavioural variant frontotemporal dementia (bvFTD), a relevant pathological model as it primarily affects the rostral PFC and alters intrinsic connectivity within the DMN and ECN. Using whole-brain voxel-based morphometry, we explored the brain regions critical for the generation and combination of remote semantic associates, respectively, but also for creative abilities, thought to involve both types of processes. Using resting state functional connectivity and gradient mapping techniques, we also explored functional connectivity profiles within the rostral PFC and how connectivity variations within this region predict creative performance.As a result, we found a critical role of the rostromedial PFC for generating remote semantic associations and of the rostrolateral PFC for combining semantic associates, while both regions were critical for creative abilities. Moreover, we showed that intrinsic connectivity of rostral PFC is organized along a mediolateral functional gradient, segregating the rostromedial PFC, connected to the DMN, and the rostrolateral PFC, connected to the ECN. Finally, we showed that the range of this functional gradient, representing the functional differentiation between the ECN and DMN, predicts creative abilities.Overall, this study advances our understanding of creative cognition, its relationships to the anatomical and functional organization of the prefrontal cortex, and its impairment in bvFTD.

Although creativity is an essential cognitive function to adapt to an ever-changing world, its neurocognitive and cerebral bases still need clarification. Current models highlight the interaction between associative and executive processes underpinned by the default mode, executive control and salience networks, with a central role of the prefrontal cortex. Hence, behavioral variant frontotemporal dementia (bvFTD), principally impacting the prefrontal cortex and the intrinsic connectivity of these three creativity-related networks, represents a unique model to study creativity. In 14 bvFTD patients and 20 matched controls, we used a simple word-to-word association task (FGAT) to explore the specific cognitive processes involved in the production of creative semantic associations. We dissociated four key cognitive components: spontaneous associative thinking, inhibition of unoriginal responses, intentional remote associative thinking, and verbal initiation. Using voxel-based morphometry and resting-state functional connectivity, we uncovered each component’s critical brain regions and their intrinsic connectivity profiles. BvFTD patients were impaired in the last three components. Two components, cognitive inhibition and intentional remote thinking, mediated the link between atrophy in critical regions and an independent measure of creative abilities. These findings advance our understanding of creative neurocognition, distinguishing components of creative thinking and clarifying their critical cerebral bases, and participate in the characterization of creativity impairment in patients with bvFTD.

REM sleep is considered a ‘hyperassociative’ state enhancing the connections between weakly related concepts, thereby facilitating memory restructuring — a critical process proposed in creative problem-solving. Here, we empirically explore this hypothesis by testing participants on a riddle before and after a 90-minute incubation period including only NREM sleep, REM sleep, or wakefulness. We quantified memory restructuring by computing differences in problem-related semantic memory network (SemNets) properties between pre- and post-incubation. For each sleep stage, we extracted fine-grained EEG measures linked to cognitive richness. REM sleep, compared to wake, broadly facilitated problem-related word associations but also reshaped the dominant problem representation by combining semantically remote concepts in memory or reducing strong but solution-irrelevant associations of ideas. Such REM sleep-related restructuring was associated with EEG measures indexing a richer cognitive state. While REM drove memory restructuring, it alone did not boost problem-solving success, suggesting that additional processes are necessary for creative breakthroughs.

Creative problem-solving is central in daily life, yet its underlying mechanisms remain elusive. Restructuring (i.e., reorganization of problem-related representations) is considered one problem-solving mechanism and may lead to an abstract problem-related representation facilitating the solving of analogous problems. Here, we used network science methodology to estimate participants’ semantic memory networks (SemNets) before and after attempting to solve a riddle. Restructuring was quantified as the difference in SemNets metrics between pre- and post-solving phases. Our results provide initial evidence that problem-related SemNets restructuring may be associated with the successful solving of the riddle and, subsequently, an analogous one. Solution-relevant concepts and semantically remote concepts became more strongly related in solvers. Only changes in semantically remote concepts were instrumental in actively solving the riddle while changes in solution-relevant concepts may reflect a pre-exposure to the solution.

What drives us to search for creative ideas, and why does it feel good to find one? While previous studies demonstrated the positive influence of motivation on creative abilities, how reward and subjective values play a role in creativity remains unknown. This study proposes to characterize the role of individual preferences (how people value ideas) in creative ideation via behavioral experiments and computational modeling. Using the Free Generation of Associates Task coupled with rating tasks, we demonstrate the involvement of valuation processes during idea generation: Preferred ideas are provided faster. We found that valuation depends on the adequacy and originality of ideas and guides response selection and creativity. Finally, our computational model correctly predicts the speed and quality of human creative responses, as well as interindividual differences in creative abilities. Altogether, this model introduces the mechanistic role of valuation in creativity. It paves the way for a neurocomputational account of creativity mechanisms. (PsycInfo Database Record (c) 2023 APA, all rights reserved).