Alizée Lopez-Persem

Whether the brain encodes the subjective value of pleasant and unpleasant situations via a single integrated circuit or through distinct pathways remains unresolved. How such signals guide choice across contexts also remains unclear. To address these questions, we recorded intracerebral activity from participants who rated pleasant and unpleasant scenarios and then made binary choices across domains and frames. Ventromedial prefrontal cortex (vmPFC) broadband gamma activity (BGA, 50–150 Hz) tracked the value of pleasant items during rating and choice, correlating positively with the most pleasant item irrespective of choice frame. Similarly, anterior insula (aIns) BGA tracked the value of unpleasant items during rating and choice, correlating negatively with the most unpleasant item irrespective of choice frame. Relative value signals in the vmPFC and aIns diverged most strongly when item domain and choice frame conflicted. These findings reveal complementary neural systems for pleasant and unpleasant valuation and their role in value-based choices.

The neural correlates of conscious perception remain debated, particularly regarding the role of extra-sensory regions such as the prefrontal cortex. One promising approach is to study the dynamical properties of neural processing in task-related and task-free contexts. A previous EEG study showed that conscious perception is associated with all-or-none late activations, giving rise to bifurcation dynamics even without a task. Here we used fMRI and near-threshold auditory stimulation to ask which brain networks give rise to these bifurcations, and how they diOer depending on task. In both contexts, stimulus intensity modulated activity within broad networks spanning sensory and extra-sensory regions, including the prefrontal cortex. These networks showed both shared and distinct components. Single-trial modelling further revealed bifurcation dynamics beyond primary sensory cortices and enabled single-trial prediction of conscious perception in both contexts. These findings resolve previous conflicting results and reveal common networks and dynamics underlying conscious perception irrespective of task.

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.

Le système cérébral des valeurs et son rôle dans la prise de décision: Les mécanismes cérébraux engagés dans la prise de décision sont loin d’être compris. Ils peuvent cependant être décomposés en plusieurs étapes : il s’agit premièrement d’assigner une « valeur » aux options considérées, c’est-à-dire une quantification subjective du désir d’obtenir chacune d’entre elles. Ensuite, il faut les comparer afin d’être capable de sélectionner celle qui a la plus grande valeur. L’assignation d’une valeur à un objet semble être effectuée par un réseau cérébral qui recoupe le réseau de la récompense identifié chez l’animal et il a été logiquement nommé le « système cérébral des valeurs ». Le travail réalisé dans cette thèse s’intéresse à la notion de valeur et aux moyens d’y avoir accès, aux propriétés du réseau cérébral d’évaluation et à son implication dans le processus de décision. La première étude a montré que les moyens utilisés pour mesurer les valeurs pouvaient être considérés comme équivalents. La deuxième étude, réalisée sur des données d’intra-électroencéphalographie humaine, a permis d’étudier la dynamique neurale du réseau cérébral d’évaluation, mais aussi d’étudier ses propriétés. La dernière expérience, faite en IRMf propose une solution générale sur l’implémentation neurale du processus de décision et révèle des mécanismes sources de biais dans le comportement jusqu’ici inexplorés. Les résultats de ces études considérés dans leur ensemble mettent en lumière certains mécanismes cognitifs de la prise de décision en explorant les propriétés neurales d’assignation de valeurs mais également en proposant un nouveau cadre d’implémentation de la décision elle-même.

Creative thinking enables humans to innovate and solve problems, via the generation of candidate ideas, their evaluation and the selection of the most promising one. While recent studies have demonstrated that idea evaluation relies on the assignment of subjective values (the assessment of how much one likes an idea, or valuation), the selection mechanism remains unknown. Using behavioral experiments and fMRI, we tested whether the selection step of creative thinking is driven by the same value comparison circuits that guide economic decisions. Participants performed creative idea production, rating, and choice tasks. We found behavioral evidence of value-based comparison during both isolated choice and overall creative idea production, in a manner that predicts creative abilities. Critically, we demonstrate that creative idea selection involves the brain valuation system and the dorsal anterior cingulate cortex: during creative thinking, these neural circuits compare candidate idea values, mirroring economic choice. Our findings reveal that idea selection is mediated by the brain’s generic valuation system, rather than specialized creative machinery, unifying theories of decision-making and creativity.

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.

Creative ideas emerge from the process of searching and combining concepts in memory, involving both associative and controlled mechanisms. How these processes unfold during memory search and relate to creativity remains unclear. We explored the neurocognitive underpinnings of semantic memory search using a clustering–switching framework and the Marginal Value Theorem (MVT) from optimal foraging theory. During an associative fluency task with polysemous words, most responses aligned with MVT predictions, but some deviated from them. These behavioral results were replicated in an independent sample. Connectome-based modeling revealed that functional brain connectivity predicted these MVT-deviant patterns and mediated the relationship between brain connectivity and creative performance. These findings suggest that the cognitive policy favoring creativity may differ from the policy optimizing fluency (i.e., MVT). This study introduces novel measures of semantic search, identifies their neurocognitive correlates, and underscores the importance of search patterns in understanding creative abilities.

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.

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.

Is a talented painter also a proficient writer? The ongoing discourse on whether creativity operates through domain-general or domain-specific mechanisms has led to challenges in our understanding of the creative process. Prior research suggests that creativity comprises two phases: idea generation and evaluation. A recent framework has proposed that the evaluation phase involves a valuation process which occurs upstream of the selection of an idea. In this framework, the value assigned to an idea, i.e., how much one likes an idea, energizes its production and drives its selection. While the role of valuation has been demonstrated in verbal semantic creativity, its domain generality remains to be tested. In this study, we assessed whether valuation is a domain-general or domain-specific process. Seventy-three participants engaged in three creativity tasks (producing semantic associations, alternate object uses, and drawings) followed by rating tasks. Using computational modeling, we found that a consistent valuation mechanism governs idea valuation across different domains. Specifically, the same value function and value parameters were shared across the evaluation of word associations, object uses and drawing completions. These findings advance our understanding of the evaluation phase of creativity, portraying the valuation component as inherently domain-general. Identifying such core components of creative ideation contributes to elucidating the cognitive mechanisms underlying creativity and provides empirical support for including valuation as a core process in creativity.