Article

Cortical Differentiation for Nouns and Verbs Depends on Grammatical Markers

Centre for Speech, Language, and the Brain, Department of Experimental Psychology, University of Cambridge, Cambridge, UK.
Journal of Cognitive Neuroscience (Impact Factor: 4.09). 09/2008; 20(8):1381-9. DOI: 10.1162/jocn.2008.20095
Source: PubMed

ABSTRACT

Here we address the contentious issue of how nouns and verbs are represented in the brain. The co-occurrence of noun and verb deficits with damage to different neural regions has led to the view that they are differentially represented in the brain. Recent neuroimaging evidence and inconsistent lesion-behavior associations challenge this view. We have suggested that nouns and verbs are not differentially represented in the brain, but that different patterns of neural activity are triggered by the different linguistic functions carried by nouns and verbs. We test these claims in a functional magnetic resonance imaging study using homophones -- words which function grammatically as nouns or verbs but have the same form and meaning -- ensuring that any neural differences reflect differences in grammatical function. Words were presented as single stems and in phrases in which each homophone was preceded by an article to create a noun phrase (NP) or a pronoun to create a verb phrase (VP), thus establishing the word's functional linguistic role. Activity for single-word homophones was not modulated by their frequency of usage as a noun or verb. In contrast, homophones marked as verbs by appearing in VPs elicited greater activity in the left posterior middle temporal gyrus (LpMTG) compared to homophones marked as nouns by occurring in NPs. Neuropsychological patients with grammatical deficits had lesions which overlapped with the greater LpMTG activity found for VPs. These results suggest that nouns and verbs do not invariably activate different neural regions; rather, differential cortical activity depends on the extent to which their different grammatical functions are engaged.

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Available from: Billi Randall, Nov 19, 2015
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    • "Modulating the inflectional model by verb dominance reveals how inflectional computations interact with the representational and combinatorial differences between verbs and nouns. Verbs have more complex lexical representations (argument structure) and carry more weight in grammatical structure building than nouns, as reflected in findings that they engage combinatorial processes more strongly than nouns when put in the appropriate grammatical environments [Longe et al., 2007; Tyler et al., 2008]. These differences emerged more clearly when we separated the activation patterns triggered by inflected verbs and inflected nouns using the dominance-modulated model. "
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    • "And although a number of functional neuroimaging studies have found verb-preferring regions, these vary across studies (see Crepaldi, Berlingeri, Paulesu, & Luzzatti, 2011, for a critical review challenging the existence of a grammatical class distinction in the brain on the basis of across-study inconsistency). Still, a number of recent fMRI studies have consistently implicated the left lateral temporal cortex (LTC), including the posterior middle temporal gyrus (pMTG), in processing verbs relative to nouns (e.g., Peelen, Romagno, & Caramazza, 2012; Romagno, Rota, Ricciardi, & Pietrini, 2012; Willms et al., 2011; Burton, Krebs-Noble, Gullapalli, & Berndt, 2009; Bedny, Caramazza, Grossman, Pascual-Leone, & Saxe, 2008; Tyler et al., 2008; Shapiro et al., 2006; Yokoyama et al., 2006; Kable, Kan, Wilson, Thompson-Schill, & Chatterjee, 2005) and, less consistently, different left frontal regions. For the latter regions, some studies have not found any effects (e.g., Peelen et al., 2012), whereas others have implicated middle frontal (e.g., Willms et al., 2011; Shapiro et al., 2006) or inferior frontal (e.g., Bedny et al., 2008) regions. "
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    No preview · Article · Feb 2014 · Journal of Cognitive Neuroscience
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    • "For the earliest epoch (the first word in the central phrase), we predict effects associated with the activation of verb lexico-syntactic knowledge, but only after the lexical identity of the word has been established (e.g., after the word’s recognition point; Marslen-Wilson, 1987) or during the processing of the second word in the central phrase. Given the lexical nature of the direct object preference measure, and on the assumption that posterior middle temporal regions represent lexical-level information relevant to processing verbs in context (Hickok and Poeppel, 2007; Tyler et al., 2008; Rodd et al., 2010), these direct object preference effects are most likely to be seen in LpMTG. "
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