Nouns, verbs, objects, actions, and abstractions: Local fMRI activity indexes semantics, not lexical categories

Noun/verb dissociations in the literature defy interpretation due to the confound between lexical category and semantic meaning; nouns and verbs typically describe concrete objects and actions. Abstract words, pertaining to neither, are a critical test case: dissociations along lexical-grammatical lines would support models purporting lexical category as the principle governing brain organisation, whilst semantic models predict dissociation between concrete words but not abstract items. During fMRI scanning, participants read orthogonalised word categories of nouns and verbs, with or without concrete, sensorimotor meaning. Analysis of inferior frontal/insula, precentral and central areas revealed an interaction between lexical class and semantic factors with clear category differences between concrete nouns and verbs but not abstract ones. Though the brain stores the combinatorial and lexical-grammatical properties of words, our data show that topographical differences in brain activation, especially in the motor system and inferior frontal cortex, are driven by semantics and not by lexical class

An fMRI study of grammatical morpheme processing associated with nouns and verbs in Chinese

This study examined whether the degree of complexity of a grammatical component in a language would impact on its representation in the brain through identifying the neural correlates of grammatical morpheme processing associated with nouns and verbs in Chinese. In particular, the processing of Chinese nominal classifiers and verbal aspect markers were investigated in a sentence completion task and a grammaticality judgment task to look for converging evidence. The Chinese language constitutes a special case because it has no inflectional morphology per se and a larger classifier than aspect marker inventory, contrary to the pattern of greater verbal than nominal paradigmatic complexity in most European languages. The functional imaging results showed BA47 and left supplementary motor area and superior medial frontal gyrus more strongly activated for classifier processing, and the left posterior middle temporal gyrus more responsive to aspect marker processing. We attributed the activation in the left prefrontal cortex to greater processing complexity during classifier selection, analogous to the accounts put forth for European languages, and the left posterior middle temporal gyrus to more demanding verb semantic processing. The overall findings significantly contribute to cross-linguistic observations of neural substrates underlying processing of grammatical morphemes from an analytic and a classifier language, and thereby deepen our understanding of neurobiology of human language.published_or_final_versio

Processing Nouns and Verbs in the Left Frontal Cortex: A Transcranial Magnetic Stimulation Study

Neuropsychological and neurophysiological studies suggest that the production of verbs in speech depends on cortical regions in the left frontal lobe. However, the precise topography of these regions, and their functional roles in verb production, remains matters of debate. In an earlier study with repetitive transcranial magnetic stimulation (rTMS), we showed that stimulation to the left anterior midfrontal gyrus disrupted verb production, but not noun production, in a task that required subjects to perform simple morphological alternations. This result raises a number of questions: for example, is the effect of stimulation focal and specific to that brain region? Is the behavioral effect limited to rule-based, regular transformations, or can it be generalized over the grammatical category? In the present study, we used rTMS to suppress the excitability of distinct parts of the left prefrontal cortex to assess their role in producing regular and irregular verbs compared to nouns. We compared rTMS to sham stimulation and to stimulation of homologous areas in the right hemisphere. Response latencies increased for verbs, but were unaffected for nouns, following stimulation to the left anterior midfrontal gyrus. No significant interference specific for verbs resulted after stimulation to two other areas in the left frontal lobe, the posterior midfrontal gyrus and Broca's area. These results therefore reinforce the idea that the left anterior midfrontal cortex is critical for processing verbs. Moreover, none of the regions stimulated was preferentially engaged in the production of regular or irregular inflection, raising questions about the role of the frontal lobes in processing inflectional morphology.Psycholog

On word class-specification: evidence from linguistics and cognitive neuroscience

The aim of the present paper is to provide a clear answer to critical aspects of the following key questions: 1) is word class-specification necessarily incorporated into lexical items? 2) does the organization of word knowledge in the brain rely on word class-specific information? To do this we combine diachronic evidence and typological observations on word classes with data on the noun/verb processing in aphasia and neuroimaging findings on the representation of verbs, adjectives and nouns and, consequently, show how linguistics and cognitive neuroscience crucially benefit from each other

Exploring the neurocognitive basis of language processing: the case of word classes and the key role of interface semantics

In the present paper, we address the question of the linking mechanisms of the multifactorial and graded conceptual space with the formally discrete language structures by 1) investigating the neurocognitive basis of interface semantics and 2) exploring the representation of word classes in the brain. Data from cognitive neuropsychological and brain imaging studies are discussed, and an answer is provided to certain critical aspects of the relationship between conceptual categorization and linguistic categorization. KEYWORDS: Conceptual categorization, linguistic categorization, interface semantics, word classes, cognitive neuropsychology, fMRIIn the present paper, we address the question of the linking mechanisms of the multifactorial and graded conceptual space with the formally discrete language structures by 1) investigating the neurocognitive basis of interface semantics and 2) exploring the representation of word classes in the brain. Data from cognitiveneuropsychological and brain imaging studies are discussed, and an answer is provided to certain critical aspects of the relationship between conceptual categorization and linguistic categorization. KEYWORDS: Conceptual categorization, linguistic categorization, interface semantics, word classes, cognitive neuropsychology, fMR

Syntax through the looking glass: A review on two-word linguistic processing across behavioral, neuroimaging and neurostimulation studies

In recent years a growing number of studies on syntactic processing has employed basic two-word constructions (e.g., “the tree”) to characterize the fundamental aspects of linguistic composition. This large body of evidence allows, for the first time, to closely examine which cognitive processes and neural substrates support the combination of two syntactic units into a more complex one, mirroring the nature of combinatory operations described in theoretical linguistics. The present review comprehensively examines behavioural, neuroimaging and neurostimulation studies investigating basic syntactic composition, covering more than forty years of psycho- and neuro-linguistic research. Across several paradigms, four key features of syntactic composition have emerged: (1) the rule-based and (2) automatic nature of the combinatorial process, (3) a central role of Broca’s area and the posterior temporal lobe in representing and combining syntactic features, and (4) the reliance on efficient bottom-up integration rather than top-down prediction

Syntax through the looking glass: A review on two-word linguistic processing across behavioral, neuroimaging and neurostimulation studies

In recent years a growing number of studies on syntactic processing has employed basic two-word constructions (e.g., “the tree”) to characterize the fundamental aspects of linguistic composition. This large body of evidence allows, for the first time, to closely examine which cognitive processes and neural substrates support the combination of two syntactic units into a more complex one, mirroring the nature of combinatory operations described in theoretical linguistics. The present review comprehensively examines behavioural, neuroimaging and neurostimulation studies investigating basic syntactic composition, covering more than 40 years of psycho- and neuro-linguistic research. Across several paradigms, four key features of syntactic composition have emerged: (1) the rule-based and (2) automatic nature of the combinatorial process, (3) a central role of Broca’s area and the posterior temporal lobe in representing and combining syntactic features, and (4) the reliance on efficient bottom-up integration rather than top-down prediction

Brain-Language Research: Where is the Progress?

Recent cognitive neuroscience research improved our understanding of where, when, how, and why language circuits emerge and activate in the human brain. Where: Regions crucial for very specific linguistic processes were delineated; phonetic features and fine semantic categories could be mapped onto specific sets of cortical areas. When: Brain correlates of phonological, syntactic and semantic processes were documented early-on, suggesting language understanding in an instant (within 250ms). How: New mechanistic network models mimicking structure and function of left-perisylvian language areas suggest that multimodal action-perception circuits — rather than separate modules for action and perception — carry the processing resources for language use and understanding. Why language circuits emerge in specific areas, become active at specific early time points and are connected in specific ways is best addressed in light of neuroscience principles governing neuronal activation, correlation learning, and, critical-ly, partly predetermined structural information wired into connections between cortical neurons and areas

From minimal dependencies to sentence contexts: neural correlates of agreement processing

289 p.Language comprehension is incremental, involving the integration of formal and conceptual information from different words, together with the need to resolve conflicting cues when unexpected information occurs. However, despite the extensive amount of findings regarding how the brain deals with these information, two essential and still open questions are 1whether the neural circuit(s) for coding syntactic and semantic information embedded in our linguistic code are the same or different, and 2whether the possible interaction(s) between these two different types of information leaves a trace in the brain response. The current thesis seeks to segregate the neuro-anatomical substrates of these processes by taking advantage of the Spanish agreement system. This system comprised those procedural mechanisms concerning the regular assignment of the number [singular, plural], person [first, second and third] and/or gender [feminine, masculine] information, associated with different sentence constituents. Experimental manipulations concerning different agreement features and the elements involved in an agreement relation, allowed us to characterize the neural network underlying agreement processing. This thesis comprised five experiments: while experiments I and II explored nominal dependencies in local as well as non-local relations, experiments III, IV and V explored subject-verb relations in a more complex sentence context. To distinguish between purely syntactic mechanisms and those where semantic and syntactic factors would interact during language comprehension, different types of agreement relations and/or agreement features were manipulated in well- and ill-formed constructions. The interaction effect between the different factors included in each experiment was always the critical comparison. In general, our results include firstly a functional dissociation between well-formed and ill-formed constructions: while ill-formed constructions recruited a bilateral distributed fronto-parietal network associated to conflict monitoring operations, not language specific, well-formed constructions recruited a left lateralized fronto-temporo-parietal network that seems to be specifically related to different aspects of phrase and sentence processing. Secondly, there was an anterior to posterior functional gradient associated to the middle and superior temporal cortex that consistently appears across experiments. Specifically, while the posterior portion of the left MTG-STG seems to be related to the storage and retrieval of lexical and morpho-syntactic information, the anterior portion of this region was related to syntactic-combinatorial building mechanisms. Critically, in the most anterior part of the left temporal cortex, corresponding with the middle and superior temporal pole, form-to-meaning mapping processes seems to be represented. Thirdly, the response of the left temporal cortex appears to be controlled by left inferior frontal regions (LIFG). Finally, left parietal regions such us the angular gyrus showed increased activation for those manipulations involving semantic factors (e.g., conceptual gender and Unagreement constructions), highlighting its crucial role in the processing of different types of semantic information (e.g., conceptual integration and semantic-discourse integration). Overall, these findings highlight the sensitivity of the agreement system to syntactic and semantic factors embedded into an agreement relation, opening new windows to the study of agreement computation and language comprehension.bcbl: basque center on cognition, brain and languag