Earlier work explored this strategy using EEG (Brown and Lehmann, 1979, Kellenbach et al., 2002 and Pulvermüller, Mohr et al., 1999) and fMRI (Vigliocco et al. 2006) but, especially in the fMRI studies, it was not always possible to control all relevant confounds in an optimal fashion. For example, Vigliocco et al. (2006) compared Italian nouns and verbs with sensory or motor features and found a semantic-topographical but not a lexical class difference. However, a shortcoming of this study was that their Italian noun/verb stimuli shared stems but differed in their affixes (e.g.
noun “arrivo” [-O] and verb “arrivare” [-ARE]) and no stimulus matching for word length, word frequency or other lexical variables was reported. This study, as many earlier ones, did not exclude important Selumetinib in vivo psycholinguistic confounds find more which might have led differences in brain activation between nouns and verbs to be overlooked. On
the other hand, the fact that ”sensory words were judged as less familiar, acquired later, and less imageable than motor words” (Vigliocco et al., 2006, p. 1791) leaves it open whether the observed differences in brain activation between word types were due to their sensorimotor semantics or to other psycholinguistic features. It is therefore of the essence to properly address the issue of putative lexical–grammatical class differences in brain activation with these pitfalls avoided, and in particular to examine the relationship of lexical class differences to the semantic differences in brain activation reported by the aforementioned authors. The debate concerning lexical vs. semantic differences as the primary factor for
neural differentiation might be addressed with the exploration of well-matched word categories orthogonalised for semantic and lexical factors, such that the contribution Liothyronine Sodium of these factors to brain activation in specific cortical areas can be clarified. Whilst nouns and verbs have generally been investigated in the context of concrete items which refer respectively to objects and actions in the world (e.g. “door” and “speak”), they are also highly typical as abstract items generally used to speak about abstract concepts or feelings (e.g. “despair” and “suffer”, “idea” and “think”) and therefore possessing few, if any, sensorimotor associations. Using typical nouns and verbs of a concrete or abstract semantic nature, we here tested predictions of theories of lexical and semantic category representation in the human brain. The lexical–grammatical approach to category-specific local brain processes postulates that the differences in word-elicited cortical activation landscapes are best described in terms of the lexical (or grammatical) categories of nouns and verbs (Daniele et al., 1994, Miceli et al., 1988 and Miceli et al., 1984; Shapiro et al., 2000, Shapiro et al.