Aprendizaje de palabras nuevas concretas y abstractas

El significado de una palabra nueva puede adquirirse extrayéndolo de un contexto lingüístico, tanto durante la lectura como durante una conversación. Aún no sabemos cómo nuestro cerebro lleva a cabo este proceso de extracción y posterior aprendizaje del significado de nuevas palabras. En esta investigación hemos simulado el aprendizaje de palabras nuevas concretas y abstractas a partir de información contextual verbal, con el fin de caracterizar las regiones cerebrales implicadas durante el curso de este proces

Functional neuroanatomy of contextual acquisition of concrete and abstract words

The meaning of a novel word can be acquired by extracting it from linguistic context. Here we simulated word learning of new words associated to concrete and abstract concepts in a variant of the human simulation paradigm that provided linguistic context information in order to characterize the brain systems involved. Native speakers of Spanish read pairs of sentences in order to derive the meaning of a new word that appeared in the terminal position of the sentences. fMRI revealed that learning the meaning associated to concrete and abstract new words was qualitatively different and recruited similar brain regions as the processing of real concrete and abstract words. In particular, learning of new concrete words selectively boosted the activation of the ventral anterior fusiform gyrus, a region driven by imageability, which has previously been implicated in the processing of concrete words

Functional neuroanatomy of meaning acquisition from context

An important issue in language learning is how new words are integrated in the brain representations that sustain language processing. To identify the brain regions involved in meaning acquisition and word learning, we conducted a functional magnetic resonance imaging study. Young participants were required to deduce the meaning of a novel word presented within increasingly constrained sentence contexts that were read silently during the scanning session. Inconsistent contexts were also presented in which no meaning could be assigned to the novel word. Participants showed meaning acquisition in the consistent but not in the inconsistent condition. A distributed brain network was identified comprising the left anterior inferior frontal gyrus (BA 45), the middle temporal gyrus (BA 21), the parahippocampal gyrus, and several subcortical structures (the thalamus and the striatum). Drawing on previous neuroimaging evidence, we tentatively identify the roles of these brain areas in the retrieval, selection, and encoding of the meaning

Neural correlates of word learning and meaning acquisition

[eng] The series of studies that comprise this dissertation are aimed at simulating vocabulary learning and meaning acquisition of different types of words, namely words which differ in imageability. For this purpose, the human simulation paradigm is the best option to approach the question of how the meanings of words are learned. It also offers the advantage of using electrophysiological and hemodynamic techniques to explore the underlying processes and neural regions that sustain on-line word learning and that, with the use of infants, would have been difficult or impossible to study. In order to study the meaning acquisition of new words, the human simulation paradigm was adopted (Gillette et al., 1999). In the first series of experiments (Chapters 2 and 3), adults were provided with congruent and incongruent semantic contexts from which they had to derive the meanings of new words. This strategy was further applied in order to understand the neural mechanisms involved in learning concrete and abstract words (Chapters 4 and 5). More specifically, Chapter 2 analyzes the interaction of semantic information congruency and meaning resolution using event-related brain potentials (ERP) (experiments 1 and 3). A different experiment explores the effects of context congruence on lexical acquisition using a self-paced reading paradigm (experiment 2). Chapter 3 examines the localization of cortical areas of successful meaning acquisition with functional magnetic resonance imaging (fMRI), and investigates the neural network for lexical learning (experiment 4). In Chapter 4, the self¬paced reading paradigm is used to study meaning acquisition of concrete and abstract words. First, a reanalysis of experiment 2 is presented (experiment 2b). Experiment 5 investigates abstract word learning from congruent and incongruent sentential contexts. Afterward, a comparison between experiments 2b and 5 is presented. In experiment 6, the simultaneous acquisition of concrete and abstract words is studied using the self¬paced paradigm. Finally, Chapter 5 examines the localization of cortical areas differently involved in meaning acquisition of concrete and abstract words using fMRI (experiment 7).[cat] El llenguatge és una capacitat humana que ha fet possible aspectes únics del pensament humà, com la creativitat, l'habilitat de pensar sobre el passat i el futur, la lògica i, totes les formes de cognició d'alt nivell. El llenguatge ens donà l'habilitat de mantenir informació de l'entorn en memòria per a poder manipular-la, i en conseqüència, tenir una eina per a comunicar idees. El llenguatge esdevingué la principal manera de transmetre i emmagatzemar el coneixement i la cultura. Degut a la importància d'aquesta increïble, però a la vegada, complicada habilitat, els humans hem d'aprendre'l durant els primers anys de vida. Un dels primers passos en aquest enigmàtic procés d'aprendre el llenguatge és aprendre les etiquetes del món. Donar un nom a quelcom optimitza la informació, i permet fer categoritzacions, que permeten generalitzacions del coneixement que ja existeix a nous exemplars, objectes o conceptes. Sota una etiqueta arbitrària, una convenció social, les característiques, funcions, parts i relacions amb altres paraules d'un concepte són emmagatzemades. L'aprenentatge d'aquestes etiquetes és un dels primers reptes que els infants han d'afrontar. Per tal d'esdevenir un usuari expert del llenguatge els infants primer han d'aprendre com es denominen les coses, quines coses pertanyen al mateix grup i quines no, és a dir, han d'aprendre a categoritzar el món i generalitzar la informació. Els infants són extremadament bons en això. Els nens comencen a produir les primeres paraules al volant del 12 mesos d'edat, aprenent unes 10 paraules noves cada dia fins al final de la secundaria. Nogensmenys, l'aprenentatge de vocabulari no s'atura al final de l'adolescència, constantment trobem paraules noves, neologismes, argots, que hem d'aprendre. A més a més, la majoria de gent haurà d'aprendre com a mínim una llengua estrangera durant la seva vida. Tot i això, l'adquisició de vocabulari en l'adultesa és molt més lenta i probablement depèn més de factors socials. Aquesta tesi està dedicada a la comprensió de com els adults aprenen el significat de noves paraules a partir del context semàntic, és a dir, estudia la vinculació d'una paraula amb un concepte utilitzant la informació semàntica proporcionada per les oracions en les que la paraula nova es troba. Així doncs, per a aquest propòsit, s'han realitzat set experiments. Dos experiments amb potencials evocats, un conductual i un utilitzant ressonància magnètica funcional (fMRI) es centren en l'efecte de la congruència del context semàntic en l'adquisició lèxica. Els següents experiments intenten profunditzar en l'aprenentatge de noves paraules investigant l'adquisició de paraules concretes i abstractes. Amb aquest propòsit s'han realitzat dos experiments conductuals i un utilitzant fMRI

Noninvasive functional and structural exploration of human subcortical structures with high resolution

Projecte de recerca elaborat a partir d’una estada al Max Planck Institute for Human Cognitive and Brain Sciences, Alemanya, entre 2010 i 2012. El principal objectiu d’aquest projecte era estudiar en detall les estructures subcorticals, en concret, el rol dels ganglis basals en control cognitiu durant processament lingüístic i no-lingüístic. Per tal d’assolir una diferenciació minuciosa en els diferents nuclis dels ganglis basals s’utilitzà ressonància magnètica d’ultra-alt camp i alta resolució (7T-MRI). El còrtex prefrontal lateral i els ganglis basals treballant conjuntament per a mitjançar memòria de treball i la regulació “top-down” de la cognició. Aquest circuit regula l’equilibri entre respostes automàtiques i d’alt-ordre cognitiu. Es crearen tres condicions experimentals principals: frases/seqüències noambigües, no-gramatical i ambigües. Les frases/seqüències no-ambigües haurien de provocar una resposta automàtica, mentre les frases/seqüències ambigües i no-gramaticals produïren un conflicte amb la resposta automàtica, i per tant, requeririen una resposta de d’alt-ordre cognitiu. Dins del domini de la resposta de control, la ambigüitat i no-gramaticalitat representen dues dimensions diferents de la resolució de conflicte, mentre per una frase/seqüència temporalment ambigua existeix una interpretació correcte, aquest no és el cas per a les frases/seqüències no-gramaticals. A més, el disseny experimental incloïa una manipulació lingüística i nolingüística, la qual posà a prova la hipòtesi que els efectes són de domini-general; així com una manipulació semàntica i sintàctica que avaluà les diferències entre el processament d’ambigüitat/error “intrínseca” vs. “estructural”. Els resultats del primer experiment (sintax-lingüístic) mostraren un gradient rostroventralcaudodorsal de control cognitiu dins del nucli caudat, això és, les regions més rostrals sostenint els nivells més alts de processament cognitiuReport for the scientific sojourn carried out at the Max Planck Institute for Human Cognitive and Brain Sciences, Germany, from 2010 to 2012. The main goal of the project was to study in detail subcortical structures, namely, the role of the basal ganglia in cognitive control during linguistic and non-linguistic processing. In order to achieve a fine-grained funcional differentiation in the different basal ganglia nuclei, ultra-high-field high resolution magnetic resonance imaging (7T-MRI) was used. The lateral prefrontal cortex and basal ganglia work together to mediate working memory and top-down regulation of cognition. This circuit regulates the balance between automatic and higher-order control responses. Three main conditions were tested: unambiguous, ungrammatical, and ambiguous sentences/sequences. Unambiguous sentences/sequences should elicit an automatic response, while ambiguous and ungrammatical sentences/sequences should conflict with an automatic response, and, hence, require a higherorder control response. Within the control response domain, ambiguity and ungrammaticality represent two different dimensions of conflict resolution, while for a temporarily ambiguous sentence/sequence a correct interpretation is available, that is not the case for ungrammatical sentences/sequences. The design included a linguistic and non-linguistic manipulation, which put to a test the hypothesis that the effects are domain-general; as well as a semantic and syntactic manipulation testing for differences in “intrinsic” vs. “structural” ambiguity/error processing. The results from the first experiment (syntactic-linguistic) showed a rostro-ventralcaudo- dorsal gradient of cognitive control within the head of the caudate nucleus, that is, the more rostral regions supporting higher levels of cognitive processing

Aprendizaje de palabras nuevas concretas y abstractas

El significado de una palabra nueva puede adquirirse extrayéndolo de un contexto lingüístico, tanto durante la lectura como durante una conversación. Aún no sabemos cómo nuestro cerebro lleva a cabo este proceso de extracción y posterior aprendizaje del significado de nuevas palabras. En esta investigación hemos simulado el aprendizaje de palabras nuevas concretas y abstractas a partir de información contextual verbal, con el fin de caracterizar las regiones cerebrales implicadas durante el curso de este proces

An anterior-posterior gradient of cognitive control within the dorsomedial striatum

Lateral prefrontal cortex and basal ganglia work together to mediate working memory and top-down regulation of cognition. This circuit regulates the balance and interactions between automatic and high-order control responses. Using ultra-high-field high-resolution functional magnetic resonance imaging (7 T-fMRI), the present study examined the role of subcortical structures in cognitive control during language processing. Participants were asked to judge the grammaticality of unambiguous, ungrammatical and ambiguous sentences. Grammatical unambiguous sentences should elicit an automatic response, while ambiguous and ungrammatical sentences should conflict with the automatic response and, hence, require a high-order control response. Within the control response domain, ambiguity and ungrammaticality represent two different dimensions of conflict resolution, while for a temporarily ambiguous sentence a correct interpretation is available, that is not the case for ungrammatical sentences. Our results reveal an anterior–posterior axis in the dorsomedial striatum with more rostral regions supporting higher levels of cognitive processing. This functional architecture mirrors the rostrocaudal hierarchical organization evidenced within the lateral prefrontal cortex

Mapping concrete and abstract meanings to new words using verbal contexts

In three experiments, we examine the effects of semantic context and word concreteness on the mapping of existing meanings to new words. We developed a new-word-learning paradigm in which participants were required to discover the meaning of a new-word form from a specific verbal context. The stimulus materials were manipulated according to word concreteness, context availability and semantic congruency across contexts. Overall, participants successfully learned the meaning of the new word whether it was a concrete or an abstract word. Concrete word meanings were discovered and learned faster than abstract word meanings even when matched on context availability. The present results are discussed considering the various hypotheses that have been used to try to explain the ‘concreteness effect’. We conclude that the present investigation provides new evidence that the concreteness effect observed in learning is due to the different organization of abstract and concrete conceptual information in semantic memory. </jats:p