20 research outputs found

    Decompositional Representation of Morphological Complexity: Multivariate fMRI Evidence from Italian.

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    Derivational morphology is a cross-linguistically dominant mechanism for word formation, combining existing words with derivational affixes to create new word forms. However, the neurocognitive mechanisms underlying the representation and processing of such forms remain unclear. Recent cross-linguistic neuroimaging research suggests that derived words are stored and accessed as whole forms, without engaging the left-hemisphere perisylvian network associated with combinatorial processing of syntactically and inflectionally complex forms. Using fMRI with a "simple listening" no-task procedure, we reexamine these suggestions in the context of the root-based combinatorially rich Italian lexicon to clarify the role of semantic transparency (between the derived form and its stem) and affix productivity in determining whether derived forms are decompositionally represented and which neural systems are involved. Combined univariate and multivariate analyses reveal a key role for semantic transparency, modulated by affix productivity. Opaque forms show strong cohort competition effects, especially for words with nonproductive suffixes (ventura, "destiny"). The bilateral frontotemporal activity associated with these effects indicates that opaque derived words are processed as whole forms in the bihemispheric language system. Semantically transparent words with productive affixes (libreria, "bookshop") showed no effects of lexical competition, suggesting morphologically structured co-representation of these derived forms and their stems, whereas transparent forms with nonproductive affixes (pineta, pine forest) show intermediate effects. Further multivariate analyses of the transparent derived forms revealed affix productivity effects selectively involving left inferior frontal regions, suggesting that the combinatorial and decompositional processes triggered by such forms can vary significantly across languages.This research was supported by an Advanced Investigator grant to WMW from the European Research Council (AdG 230570 NEUROLEX) and by MRC Cognition and Brain Sciences Unit (CBSU) funding to WMW (U.1055.04.002.00001.01). Computing resources were provided by the MRC CBSU.This is the author accepted manuscript. The final version is available from MIT Press via http://dx.doi.org/10.1162/jocn_a_0100

    Distinct fronto-temporal substrates of distributional and taxonomic similarity among words: evidence from RSA of BOLD signals

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    A class of semantic theories defines concepts in terms of statistical distributions of lexical items, basing meaning on vectors of word co-occurrence frequencies. A different approach emphasizes abstract hierarchical taxonomic relationships among concepts. However, the functional relevance of these different accounts and how they capture information-encoding of lexical meaning in the brain still remains elusive. We investigated to what extent distributional and taxonomic models explained word-elicited neural responses using cross-validated representational similarity analysis (RSA) of functional magnetic resonance imaging (fMRI) and model comparisons. Our findings show that the brain encodes both types of semantic information, but in distinct cortical regions. Posterior middle temporal regions reflected lexical-semantic similarity based on hierarchical taxonomies, in coherence with the action-relatedness of specific semantic word categories. In contrast, distributional semantics best predicted the representational patterns in left inferior frontal gyrus (LIFG, BA 47). Both representations coexisted in the angular gyrus supporting semantic binding and integration. These results reveal that neuronal networks with distinct cortical distributions across higher-order association cortex encode different representational properties of word meanings. Taxonomy may shape long-term lexical-semantic representations in memory consistently with the sensorimotor details of semantic categories, whilst distributional knowledge in the LIFG (BA 47) may enable semantic combinatorics in the context of language use. Our approach helps to elucidate the nature of semantic representations essential for understanding human language

    Experientially-grounded and distributional semantic vectors uncover dissociable representations of conceptual categories

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    Neuronal populations code similar concepts by similar activity patterns across the human brain's semantic networks. However, it is unclear to what extent such meaning-to-symbol mapping reflects distributional statistics, or experiential information grounded in sensorimotor and emotional knowledge. We asked whether integrating distributional and experiential data better distinguished conceptual categories than each method taken separately. We examined the similarity structure of fMRI patterns elicited by visually presented action- and object-related words using representational similarity analysis (RSA). We found that the distributional and experiential/integrative models respectively mapped the high-dimensional semantic space in left inferior frontal, anterior temporal, and in left precentral, posterior inferior/middle temporal cortex. Furthermore, results from model comparisons uncovered category-specific similarity patterns, as both distributional and experiential models matched the similarity patterns for action concepts in left fronto-temporal cortex, whilst the experiential/integrative (but not distributional) models matched the similarity patterns for object concepts in left fusiform and angular gyrus

    Accedere al mercato della casa in Cina attraverso la ricerca sul progetto di architettura. Il programma multidisciplinare Piemonte home design

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    Il mercato immobiliare cinese, sviluppatosi attraverso una serie accelerata di passaggi dopo le riforme del 1988, costituisce non solo un sistema in forte sviluppo e trasformazione, ma anche un luogo in cui istituzioni di governo e regolazione, università e attori economici hanno la possibilità di sperimentare approcci ibridi condivisi, che si discostano dalla convenzionale separazione fra i programmi accademici di ricerca sull’architettura e il mondo immobiliare. Con queste premesse, l’articolo illustra l’approccio metodologico e operativo, le ipotesi e gli obiettivi di un progetto di ricerca portato avanti dal gruppo di ricerca China Room – Politecnico di Torino in partnership con la Camera di Commercio di Torino, a partire da settembre 2020. Il progetto si colloca all’interno del più ampio programma di internazionalizzazione e business development Piemonte Home Design, in supporto delle imprese piemontesi del settore arredo e decorazione. Illustrando l’approccio metodologico del programma, composto da tre ambiti d’azione distinti e complementari — una ricerca empirica strumentale alla conoscenza del mercato, la progettazione architettonica di un modello di casa integrato, e una strategia di trasferimento di queste competenze in uno specifico contesto socio-economico —, il paper vuole mostrare le potenzialità di una progettazione strategica basata sulla ricerca, a supporto di strategie promozionali e istituzionali, nel raggiungere obiettivi di interesse commerciale per l’Italia e la Cina. L’articolo sostiene, quindi, la necessità di una maggior integrazione tra ricerca, competenze tecnico-culturali e progettuali proprie dell’architettura per predisporre un potenziale di ricadute multidimensionali, che spazino dall’ecosistema produttivo e socioeconomico all’ambiente costruito

    Cerebral correlates of multimodal pointing: An fmri study of prosodic focus, syntactic extraction, digital- and ocular- pointing

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    International audienceDeixis or pointing plays a crucial role in language acquisition and speech communication and can be conveyed in several modalities. The aim of this paper is to explore the cerebral substrate of multimodal pointing actions. We present an fMRI study of pointing including: 1) index finger pointing, 2) eye pointing, 3) prosodic focus production, 4) syntactic extraction (during speech production). Fifteen subjects were examined while they gave digital, ocular and oral responses inside the 3T imager. Results of a random effect group analysis show that digital and prosodic pointings recruit the parietal lobe bilaterally, while ocular and syntactic pointings do not. A grammaticalization process is suggested to explain the lack of parietal activation in the syntactic condition. Further analyses are carried out on the link between digital and prosodic parietal activations

    Brain correlates of action word memory revealed by fMRI

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    Understanding language semantically related to actions activates the motor cortex. This activation is sensitive to semantic information such as the body part used to perform the action (e.g. arm-/leg-related action words). Additionally, motor movements of the hands/feet can have a causal effect on memory maintenance of action words, suggesting that the involvement of motor systems extends to working memory. This study examined brain correlates of verbal memory load for action-related words using event-related fMRI. Seventeen participants saw either four identical or four different words from the same category (arm-/leg-related action words) then performed a nonmatching-to-sample task. Results show that verbal memory maintenance in the high-load condition produced greater activation in left premotor and supplementary motor cortex, along with posterior-parietal areas, indicating that verbal memory circuits for action-related words include the cortical action system. Somatotopic memory load effects of arm- and leg-related words were observed, but only at more anterior cortical regions than was found in earlier studies employing passive reading tasks. These findings support a neurocomputational model of distributed action-perception circuits (APCs), according to which language understanding is manifest as full ignition of APCs, whereas working memory is realized as reverberant activity receding to multimodal prefrontal and lateral temporal areas

    Body-part-specific Representations of Semantic Noun Categories.

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    Word meaning processing in the brain involves ventrolateral temporal cortex, but a semantic contribution of the dorsal stream, especially frontocentral sensorimotor areas, has been controversial. We here examine brain activation during passive reading of object-related nouns from different semantic categories, notably animal, food, and tool words, matched for a range of psycholinguistic features. Results show ventral stream activation in temporal cortex along with category-specific activation patterns in both ventral and dorsal streams, including sensorimotor systems and adjacent pFC. Precentral activation reflected action-related semantic features of the word categories. Cortical regions implicated in mouth and face movements were sparked by food words, and hand area activation was seen for tool words, consistent with the actions implicated by the objects the words are used to speak about. Furthermore, tool words specifically activated the right cerebellum, and food words activated the left orbito-frontal and fusiform areas. We discuss our results in the context of category-specific semantic deficits in the processing of words and concepts, along with previous neuroimaging research, and conclude that specific dorsal and ventral areas in frontocentral and temporal cortex index visual and affective–emotional semantic attributes of object-related nouns and action-related affordances of their referent objects

    Decoding Brain Activity Associated with Literal and Metaphoric Sentence Comprehension Using Distributional Semantic Models

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    Recent years have seen a growing interest within the natural language processing (NLP)community in evaluating the ability of semantic models to capture human meaning representation in the brain. Existing research has mainly focused on applying semantic models to de-code brain activity patterns associated with the meaning of individual words, and, more recently, this approach has been extended to sentences and larger text fragments. Our work is the first to investigate metaphor process-ing in the brain in this context. We evaluate a range of semantic models (word embeddings, compositional, and visual models) in their ability to decode brain activity associated with reading of both literal and metaphoric sentences. Our results suggest that compositional models and word embeddings are able to capture differences in the processing of literal and metaphoric sentences, providing sup-port for the idea that the literal meaning is not fully accessible during familiar metaphor comprehension

    A Role for the Motor System in Binding Abstract Emotional Meaning

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    Sensorimotor areas activate to action- and object-related words, but their role in abstract meaning processing is still debated. Abstract emotion words denoting body internal states are a critical test case because they lack referential links to objects. If actions expressing emotion are crucial for learning correspondences between word forms and emotions, emotion word–evoked activity should emerge in motor brain systems controlling the face and arms, which typically express emotions. To test this hypothesis, we recruited 18 native speakers and used event-related functional magnetic resonance imaging to compare brain activation evoked by abstract emotion words to that by face- and arm-related action words. In addition to limbic regions, emotion words indeed sparked precentral cortex, including body-part–specific areas activated somatotopically by face words or arm words. Control items, including hash mark strings and animal words, failed to activate precentral areas. We conclude that, similar to their role in action word processing, activation of frontocentral motor systems in the dorsal stream reflects the semantic binding of sign and meaning of abstract words denoting emotions and possibly other body internal states
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