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Lopez-Persem, A.

Publications and source records attributed to Lopez-Persem, A..

9 recordsLinked to original sources

Bifurcation dynamics in a shared network beyond sensory areas characterize conscious auditory perception independently of report

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 differ 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.

neuroscience↗

From default to creativity: prefrontal and cerebellar contributions of the default mode network to goal-directed remote thinking

Creativity is a hallmark of human cognition, characterized by the ability to connect seemingly distant concepts or ideas. Existing theories suggest that remote thinking can be achieved either spontaneously (constrained by the structure of semantic memory) or in a goal-directed manner (constrained by a creative goal). The present study investigates the neural correlates of goal-directed remote thinking, defined as the intentional production of semantically distant associations. Using a simple word-to-word association task comprising both a spontaneous condition and a goal-directed creative condition, we investigated Goal-directed Remoteness as the extra semantic distance traveled away from spontaneous responses when instructed to think creatively. Task-based functional MRI in 38 healthy young adults identified brain regions whose activation scaled with Goal-directed Remoteness. The results revealed that activity in the rostromedial and dorsomedial prefrontal cortex and the right cerebellar Crus I & II was positively modulated by Goal-directed Remoteness. Control analyses confirmed the robustness of these findings independently of the cue-words semantic or linguistic properties. Follow-up seed-based resting-state functional connectivity analyses characterized the intrinsic connectivity profiles of the revealed regions. They showed that rostromedial and dorsomedial prefrontal and cerebellar Crus I & II regions formed a functionally interconnected network primarily overlapping with the default-mode network (DMN). Our findings challenge the traditional view of the DMN as supporting only passive or spontaneous cognition. Instead, they reveal a prefronto-cerebellar DMN subnetwork supporting goal-directed remote thinking, a key component of creative cognition. Within this network, the rostromedial and dorsomedial prefrontal cortex and cerebellar Crus I & II play an active role in the intentional generation of connections between distant concepts.

neuroscience↗

Neural investigation of idea selection during creative thinking reveals value-based mechanisms

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 brains generic valuation system, rather than specialized creative machinery, unifying theories of decision-making and creativity.

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Choosing the best or avoiding the worst: complementary and opponent value signals in the human brain

Whether the brain encodes the subjective value of pleasant and unpleasant situations via a single integrated circuit or through distinct pathways remains unresolved. It is also unclear how neural value signals guide choices when the context involves choosing the most favorable option or avoiding the most unfavorable one. To address these questions, we recorded intracerebral activity from 27 participants as they first rated pleasant and unpleasant scenarios and then made binary choices across all combinations of item domain (pleasant/unpleasant) and choice frame (choose best/worst). Ventromedial prefrontal cortex (vmPFC) broadband gamma activity (BGA, 50-150 Hz) tracked the value of pleasant items during rating and pre-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 pre-choice, correlating negatively with the most unpleasant item irrespective of choice frame. The difference in relative value correlations between the vmPFC and aIns was larger for choices involving a conflict between item domain and choice frame, consistent with slower response times and choices less aligned with value differences in these trials. These findings reveal dissociable yet complementary neural systems for pleasant and unpleasant valuation and highlight how such signals may guide flexible decision-making across contexts.

neuroscience↗

Creativity involves the subjective valuation of ideas via the Brain Valuation System.

Creative thinking is composed of a generation phase, where individuals form candidate ideas, and an evaluation phase, where individuals monitor the quality of their ideas, in terms of both their originality and adequacy, to select the best one. Here, we conceptualize creative evaluation as a specific type of decision-making, where participants attribute subjective values to ideas to guide their choice. Yet, while subjective values and preferences have been the focus of many studies in classical decision-making, their involvement in creative decision-making remains largely unexplored. Combining creative generation tasks and rating tasks, the present study demonstrates that individuals assign subjective values to ideas and that these values depend on a relative balance of the ideas originality and adequacy, which is determined by individual preferences and predicts their creative abilities. Using functional Magnetic Resonance Imaging, we found that the human reward system encodes the subjective value of ideas, and that the Default Mode and the Executive Control Networks, rather than being split into idea generation and evaluation, respectively reflect the originality and adequacy of ideas. Interestingly, the relative functional connectivity of the Default Mode and Executive Control Networks with the human reward system correlates with the relative balance of adequacy and originality in individuals preferences. These results bridge a gap in the current literature by providing new evidence regarding the neural bases for originality and adequacy monitoring and add valuation to the incomplete behavioral and neural accounts of creativity, offering perspectives on the influence of individual preferences on creative abilities.

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How subjective idea valuation energizes and guides creative idea generation

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. Public Significance StatementThis study addresses the role of individual preferences in creativity. It demonstrates that preferences for ideas energize creative idea production: the more participants like their ideas, the faster they provide them. Moreover, preferences rely on an equilibrium between the adequacy and originality of ideas and vary across individuals. This study introduces a computational model which incorporates individual preferences and that correctly predicts the speed and quality of responses in a creative idea generation task, as well as inter-individual differences in creative abilities. Comparison of several versions of this model demonstrated that preferences guide the selection of creative responses.

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Time course of EEG power during creative problem-solving with insight or remote thinking

Problem-solving often requires creativity and is critical in everyday life. However, the neurocognitive mechanisms underlying creative problem-solving remain poorly understood. Two mechanisms have been highlighted: forming new connections from and between the problem elements and insight solving (with a sudden realization of a solution). We examined EEG activity during an adapted version of a classical insight problem task, the Remote Associates Test, that requires finding a word connecting three words. It allowed us to explore remoteness in semantic connections (by varying the remoteness of the solution word across trials) and insight solving (identified as a "Eureka" moment reported by the participants). Semantic remoteness was associated with a power increase in alpha band (8-12Hz) in a left parieto-temporal cluster, beta band (13-30Hz) in a right fronto-temporal cluster in the early phase of the task, and theta band (3-7Hz) in frontal cluster before the participants responded. Insight solving was associated with power increase preceding the response in alpha and gamma band (31-60Hz) in left temporal clusters and theta band in a frontal cluster. Source reconstructions show the brain regions associated with these clusters. Overall, our findings shed new light on the dynamic of some of the mechanisms involved in creative problem-solving.

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Differential functional connectivity underlying asymmetric reward-related activity in human and non-human primates

The orbitofrontal cortex (OFC) is a key brain region involved in complex cognitive functions such as reward processing and decision-making. Neuroimaging studies have shown unilateral OFC response to reward-related variables, however, those studies rarely discussed the lateralization of this effect. Yet, some lesion studies suggest that the left and right OFC contribute differently to cognitive processes. We hypothesized that the OFC asymmetrical response to reward could reflect underlying hemispherical difference in OFC functional connectivity. Using restingstate and reward-related MRI data from humans and from rhesus macaques, we first identified a specific asymmetrical response of the lateral OFC to reward in both species. Crucially, the subregion showing the highest reward-related asymmetry (RRA) overlapped with the region showing the highest functional connectivity asymmetry (FCA). Furthermore, the two types of functional asymmetries were found to be significantly correlated across humans. Altogether, our results suggest a similar pattern of functional specialization between the left and right OFC is present in two primate species.

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The human ventromedial prefrontal cortex sulcal morphology and its influence on its functional organization.

The ventromedial prefrontal cortex (vmPFC), which comprises several distinct cytoarchitectonic areas, is a key brain region supporting decision-making processes and it has been shown to be one of the main hubs of the Default Mode Network, a network classically activated during resting state. We here examined the inter-individual variability in the vmPFC sulcal morphology in 57 humans (37 females) and demonstrated that the presence/absence of the inferior rostral sulcus and the subgenual intralimbic sulcus influences significantly the sulcal organization of this region. Furthermore, the sulcal organization influences the location of the vmPFC peak of the Default Mode Network, demonstrating that the location of functional activity can be affected by local sulcal patterns. These results are critical for the investigation of the function of the vmPFC and show that taking into account the sulcal variability might be essential to guide the interpretation of neuroimaging studies.\n\nSIGNIFICANCE STATEMENTThe ventromedial prefrontal cortex (vmPFC) is one of the main hubs of the Default Mode Network and plays a central role in value coding and decision-making. The present study provides a complete description of the inter-individual variability of anatomical morphology of this large portion of prefrontal cortex and its relation to functional organization. We have shown that two supplementary medial sulci predominantly determine the organization of the vmPFC, which in turn affect the location of the functional peak of activity in this region. Those results show that taking into account the variability in sulcal patterns might be essential to guide the interpretation of neuroimaging studies of the human brain and of the vmPFC in particular.

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