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Ripolles, P.

Publications and source records attributed to Ripolles, P..

11 recordsLinked to original sources

Striatal activity during contextual word learning is influenced by children's reading ability

Contextual word learning is a fundamental mechanism for vocabulary acquisition during childhood. In adults, successful inference of word meaning from context is intrinsically rewarding, and is associated with greater enjoyment and greater activity in reward-related brain regions. Whether similar reward mechanisms support word learning in children, and whether they differ as a function of ability, remains unknown. We used functional magnetic resonance imaging (fMRI) to examine neural responses during contextual word learning in 25 children aged 11-13 years with typical reading skills and in 20 age-matched children with dyslexia. Neurotypical readers showed enhanced activation in core reward-processing regions, including the ventral striatum, when successfully learning the meanings of novel words. In contrast, children with dyslexia did not exhibit comparable reward-related responses despite performing the same task. Crucially, this group difference was specific to word learning, as no significant group differences were observed in ventral striatal responses during a non-linguistic monetary reward task. In addition, to confirm the behavioural relevance of these neural findings, we examined an age-matched, independent sample of children. We found that stronger reading skills were associated with greater enjoyment during successful word learning. Together, these results suggest that interactions between reward and language systems during contextual word learning is influenced by reading proficiency. Reduced intrinsic reward responses to successful language learning may contribute to differences in reading development and have implications for the design of more engaging and effective reading interventions for struggling readers. Significance statementWe investigated how school-age childrens brains learn new words from context, highlighting the important role of reward systems in this process. We show that ventral striatum, a core region associated with reward processing, is activated when children learn the meaning of new words. This suggests learning the meaning of a new word can be its own reward, driving further learning and engagement. Yet, children with dyslexia showed reduced brain activity in the ventral striatum during language learning, even when they successfully learned words. These findings underscore the importance of understanding the mechanisms through which learning becomes rewarding, with implications for designing more engaging and effective reading interventions

neuroscience↗

A Shared Neural Network for Highly Liked and Disliked Music

Music research has increasingly focused on neural responses to naturalistic stimuli. The neural correlates of music-induced peak moments of pleasure (e.g., chills) have been well-studied; data on other types of aesthetic responses, such as judgments of beauty, goodness, or liking are sparse. Among these, liking is of particular interest given its complex nature and its ubiquity in everyday--and musical--experiences. In this functional magnetic resonance imaging (fMRI) study, 26 participants listened to musical excerpts while continuously rating how much they liked the music. In addition, subjects provided an overall liking judgment at the end of each musical piece. Participants musical preferences manifested remarkably early and were sustained over time, with the value of the continuous rating at the end of each piece showing the strongest correlation with the overall ratings. At the neural level, highly liked and disliked musical pieces activated a shared neural network previously associated with the processing of both positive and negative emotional stimuli. This network encompassed the anterior cingulate cortex, limbic system, basal ganglia, and precuneus. These activations reflected individual differences, such that participants with greater trait-level responsiveness to artistic stimuli showed stronger engagement of this network while listening to music. Finally, the default-mode network was associated with the slope of the continuous ratings, suggesting that the faster participants liked a musical excerpt, the more disengaged this network became. In linking behavior and brain function to better characterize the way humans make aesthetic judgments of music the data support a model in which preferences and aesthetic choices are modulated by brain circuits associated with emotion and reward.

neuroscience↗

Seeing is Feeling: How Aphantasia Alters Emotional Engagement with Stories

Visual imagery is thought to act as an emotional amplifier, potentially contributing to narrative engagement. To examine this, we conducted two experiments in which participants were presented with emotionally charged audio and video story excerpts. Experiment 1 included 84 online participants from the general population, while Experiment 2 involved 25 individuals with aphantasia (the inability to generate mental images) and 25 controls. In both experiments we assessed narrative engagement behaviorally using the Narrative Engagement Questionnaire (NEQ), while for Experiment 2 we also measured physiological responses. We found a main effect of modality, with video stimuli scoring higher across all NEQ subscales in both experiments. Notably, in experiment 2, a significant group effect on emotional--but not cognitive--engagement emerged, with aphantasics reporting less emotional engagement than controls. Moreover, controls experienced higher heart rate during audio narratives, while aphantasics had a similar heart rate across both modalities. Our results suggest that the enhanced physiological response seen in non-aphantasics during audio narratives is driven by the mental effort required to generate imagery. Furthermore, this capacity for visual imagery appears to enhance emotional engagement with stories. This highlights mental imagerys role in both subjective and physiological responses, emphasizing distinct cognitive processes during narrative engagement.

physiology↗

Improvisation and Live Accompaniment Increase Motor Response and Reward During a Music Playing Task

Music provides an abstract reward that can enhance learning and motivation in humans. While music is often combined with exercise to improve performance and to upregulate mood, the relationship between music-induced reward and motor output is poorly understood. Here, we study music reward and motor output at the same time by capitalizing on music playing. Specifically, we investigate the effects of music improvisation and live accompaniment on motor, autonomic, and affective responses. Thirty adults performed a rhythm tapping task while (i) improvising or maintaining the beat and (ii) with live or recorded accompaniment. Motor response was characterized by acceleration of hand movements (accelerometry), wrist flexor and extensor muscle activation (electromyography), and the number of beats played. Autonomic arousal was measured by tonic response of electrodermal activity (EDA) and heart rate (HR). Affective responses were measured by a 12-item Likert scale. The combination of improvisation and live accompaniment, as compared to all other conditions, significantly increased acceleration of hand movements and muscle activation, as well as participant reports of enjoyment during music-playing. Improvisation, regardless of type of accompaniment, increased the number of beats played and autonomic arousal (including tonic EDA responses and several measures of HR), as well as participant reports of challenge. Importantly, increased motor response was associated with increased enjoyment during music improvisation only and not while participants were maintaining the beat. The increased motor responses achieved with improvisation and live accompaniment have important implications for enhancing dose of movement during music-based interventions for stroke rehabilitation. Significance StatementMusic provides a rewarding stimulus and improves motor performance and learning. However, the relationship between music reward and motor output is poorly understood. Here, we show that music improvisation with live accompaniment increased acceleration and muscle activation during movement, and that this increase in motor response was associated with increased enjoyment only when improvising. These findings are important for developing music interventions that target improved motor performance and learning in exercise and physical rehabilitation.

physiology↗

Tracking the online construction of linguistic meaning through negation

Combinatoric linguistic operations underpin human language processes, but how meaning is composed and refined in the mind of the reader is not well understood. We address this puzzle by exploiting the ubiquitous function of negation. We track the online effects of negation ("not") and intensifiers ("really") on the representation of scalar adjectives (e.g., "good") in parametrically designed behavioral and neurophysiological (MEG) experiments. The behavioral data show that participants first interpret negated adjectives as affirmative and later modify their interpretation towards, but never exactly as, the opposite meaning. Decoding analyses of neural activity further reveal significant above chance decoding accuracy for negated adjectives within 600 ms from adjective onset, suggesting that negation does not invert the representation of adjectives (i.e., "not bad" represented as "good"); furthermore, decoding accuracy for negated adjectives is found to be significantly lower than that for affirmative adjectives. Overall, these results suggest that negation mitigates rather than inverts the neural representations of adjectives. This putative suppression mechanism of negation is supported by increased synchronization of beta-band neural activity in sensorimotor areas. The analysis of negation provides a steppingstone to understand how the human brain represents changes of meaning over time.

neuroscience↗

Entering into a self-regulated learning mode prevents detrimental effect of feedback removal on memory

Recently, we provided causal evidence that self-regulated dopamine signaling enhanced long-term memory formation in the absence of any external feedback or reward (Ripolles et al., 2016, 2018) if a congruent meaning inferred from semantic context (DA-dependent learning), while DA-signals were absent if no congruent meaning could be inferred (DA-independent learning). Here, we investigated the interaction of self-regulated learning with externally-regulated DA-signalling by providing external performance feedback in the first or second half of trials. We found that removing feedback during DA-dependent learning lowered subsequent recognition rates a day later, whereas recognition remained high in the group which received feedback only in the second half. In contrast, feedback modestly enhanced recognition rates for both groups for DA-independent learning. Our findings suggest that external reinforcers can selectively impair DA-dependent memories if internal DA-dependent processes are not already established and highlights the relevance of self-regulated learning in education to support stable memory formation.

neuroscience↗

Statistical learning as reinforcement learning phenomena

Statistical learning (SL) is the ability to extract regularities from the environment. In the domain of language, this ability is fundamental in the learning of words and structural rules. In lack of reliable online measures, statistical word and rule learning have been primarily investigated using offline (post-familiarization) tests, which gives limited insights into the dynamics of SL and its neural basis. Here, we capitalize on a novel task that tracks the online statistical learning of language rules combined with computational modelling to show that online SL responds to reinforcement learning principles rooted in striatal function. Specifically, we demonstrate - on two different cohorts - that a Temporal Difference model, which relies on prediction errors, accounts for participants online learning behavior. We then show that the trial-by-trial development of predictions through learning strongly correlates with activity in both ventral and dorsal striatum. Our results thus provide a detailed mechanistic account of language-related SL and an explanation for the oft-cited implication of the striatum in SL tasks. This work, therefore, bridges the longstanding gap between language learning and reinforcement learning phenomena.

neuroscience↗

Population-level differences in the neural substrates supporting Statistical Learning

The ability to extract regularities from the environment is arguably an adaptive characteristic of intelligent systems. In the context of speech, statistical learning is thought to be an important mechanism for language acquisition. By considering individual differences in speech auditory-motor synchronization, an independent component analysis of fMRI data revealed that the neural substrates of statistical word form learning are not fully shared across individuals. While a network of auditory and superior pre/motor regions is universally activated in the process of learning, a fronto-parietal network is instead additionally and selectively engaged by some individuals, boosting their performance. Furthermore, interfering with the use of this network via articulatory suppression (producing irrelevant speech during learning) normalizes performance across the entire sample. Our work provides novel insights on language-related statistical learning and reconciles previous contrasting findings, while highlighting the need to factor in fundamental individual differences for a precise characterization of cognitive phenomena.

neuroscience↗

Dopaminergic signalling modulates reward-driven music memory consolidation

Previously, we provided causal evidence for a dopamine-dependent effect of intrinsic reward on memory during self-regulated learning (Ripolles et al., 2016; Ripolles et al., 2018). Here, we further investigated the dopamine-dependent link between reward and memory by focusing on one of the most iconic abstract rewards in humans: music. Twenty-nine healthy participants listened to unfamiliar excerpts--which had to be remembered following a consolidation period--after the intake of a dopaminergic antagonist, a dopaminergic precursor, and a placebo across three separated sessions. The intervention modulated the pleasantness experienced during music-listening and memory recognition of the presented songs (i.e., lower with the antagonist, higher with the precursor) in individuals with higher sensitivity to musical reward. Our work highlights the flexibility of the human dopaminergic system, which is able to enhance memory formation not only through explicit and/or primary reinforcers but also via intrinsic, abstract, or aesthetic rewards of different natures.

neuroscience↗

Integrating When and What Information in the Left Parietal Lobe Allows Language Rule Generalization

A crucial aspect when learning a language is discovering the rules that govern how words are combined in order to convey meanings. Since rules are characterized by sequential co-occurrences between elements (e.g. These cupcakes are unbelievable), tracking the statistical relationships between these elements is fundamental. However, statistical learning alone cannot fully account for the ability to create abstract rule representations that can be generalized, a paramount requirement of linguistic rules. Here, we provide evidence that, after the statistical relations between words have been extracted, the engagement of goal-directed attention is key to enable rule generalization. Incidental learning performance during a rule-learning task on an artificial language revealed a progressive shift from statistical learning to goal-directed attention. In addition, and consistent with the recruitment of attention, fMRI analyses of late learning stages showed left parietal activity within a broad bilateral dorsal fronto-parietal network. Critically, rTMS on participants peak of activation within the left parietal cortex impaired their ability to generalize learned rules to a structurally analogous new language. No stimulation or rTMS on a non-relevant brain region did not have the same interfering effect on generalization. Performance on an additional attentional task showed that rTMS on the same parietal site hindered participants ability to integrate what (stimulus identity) and when (stimulus timing) information about an expected target. The present findings suggest that learning rules from speech is a two-stage process: following statistical learning, goal-directed attention -involving left parietal regions- integrates what and when stimulus information to facilitate rapid rule generalization.

neuroscience↗

Intrinsically regulated learning is modulated by synaptic dopamine availability

We recently provided evidence that an intrinsic reward-related signal--triggered by successful learning in absence of any external feedback--modulated the entrance of new information into long-term memory via the activation of the dopaminergic midbrain, hippocampus, and ventral striatum (the SN/VTA-Hippocampal loop; Ripolles et al., 2016). Here, we used a double-blind, within-subject randomized pharmacological intervention to test whether this learning process is indeed dopamine-dependent. A group of healthy individuals completed three behavioural sessions of our learning task after the intake of different pharmacological treatments: a dopaminergic precursor, a dopamine receptor antagonist or a placebo. Results show that the pharmacological intervention bidirectionally modulated behavioral measures of both learning and pleasantness, inducing memory benefits after 24 hours only for those participants with a high sensitivity to reward. These results provide causal evidence for a dopamine-dependent mechanism instrumental in intrinsically regulated learning, and further suggest that subject-specific dopamine sensitivity drastically alters learning success.

neuroscience↗