Abstract not found

The current study addresses the controversial issue of how different grammatical categories are neurally processed. Several lesion-deficit studies suggest that distinct neural substrates underlie the representation of nouns and verbs, with verb deficits associated with damage to left inferior frontal gyrus (LIFG) and noun deficits with damage to left temporal cortex. However, this view is not universally shared by neuropsychological and neuroimaging studies. We have suggested that these inconsistencies may reflect interactions between the morphological structure of nouns and verbs and the processing implications of this, rather than differences in their neural representations (Tyler et al. 2004). We tested this hypothesis using eventrelated functional magnetic resonance imaging, to scan subjects performing a valence judgment on unambiguous nouns and verbs, presented as stems (‘snail, hear’) and inflected forms (‘snails, hears’). We predicted that activations for noun and verb stems would not differ, whereas inflected verbs would generate more activation in left frontotemporal areas than inflected nouns. Our findings supported this hypothesis, with greater activation of this network for inflected verbs compared with inflected nouns. These results support the claim that form class is not a first-order organizing principle underlying the representation of words but rather interacts with the processes that operate over lexical representations.

INTRODUCTION Behavioral effect of interest Phonological similarity without semantic similarity delays reaction times (RTs) in lexical decision. spinach SPIN slower than muffler SPIN lizard WIZARD slower than table WIZARD (e.g. Rastle et al. 2000, Gonnerman 2000, Grainger and Ferrand 1994, etc.) Question Is the inhibition suppression of lexical activation time level of activation resting level spinach spin excitation inhibition Spinach initially activates spin but when the input no longer supports spin, it is suppressed below resting level. Consequently, RT is delayed for a target SPIN when preceded by spinach. or a competition effect? time level of activation resting level spinach spin excitation Spinach activates spin but doesnt suppress it -- rather, when the input no longer supports spin, its activation simply ceases to increase. RT is delayed for a target SPIN when<

and impaired readers as a test of their adequacy (see Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; Grainger & Jacobs, 1996; Plaut, McClelland, Seidenberg, & Patterson, 1996; Zorzi, Houghton, & Butterworth, 1998). Yet for all of the advancement that the past decade has seen, a complete theory of single-word processing remains somewhat distant, with numerous commitments regarding, for example, the processing of polysyllabic and polymorphemic words, still to be made. In this chapter, we focus specifically on some of the problems that words comprised of more than one morpheme present to modellers of single-word reading. At present, none of the aforementioned computational models (that have been evaluated extensively against benchmark findings of visual word recognition and reading aloud) deals effectively with such words. However, clear interest in extending our understanding of reading to polymorphemic words has been evident in recent years, with a surge of experimental work (s

Five unmasked- and four masked-priming lexical decision experiments were carried out in Spanish in order to probe the data structures and processing routines that are exploited during the comprehension of inflected words. In unmasked priming, responses to targets (e.g., mor-os `Moors') were inhibited when they were preceded by stem-homograph primes (mor-ir `to die') compared to unrelated control primes (sill-a `chair'), and this inhibitory effect was over and above a weak inhibitory effect found for orthographic relative primes (moral `moral'). Stemhomograph inhibition is interpreted as a consequence of morphological decomposition in lexical access. In additional experiments, this inhibitory effect was observed when targets were preceded by primes that were not themselves stem-homographic with the target, but rather were stemallomorphic variants of the stem-homograph words (muer-e `she/he/it dies'). Because target inhibition was found for primes whose inflectional stems are not strictly ambiguous in terms of form, it suggests that the inhibitory effect arises at a level where form-neutral, morphologically abstract (lemma) representations are encoded. The results observed in masked (subliminal) priming contrast with those observed in unmasked priming. When the primes were presented subliminally, stem-homograph priming (mor-a ---mor-os) was facilitative, while orthographic relative priming (moral ---mor-os), was neither facilitative nor inhibitory. This was taken as further evidence that stems are decomposed at the form level, and that ambiguous decomposed stems, such as mor-, activate multiple (compatible) lemma representations during the initial stages of lexical access. Moreover, the facilitative effect observed in masked stem-homograph priming suggests that the lem...

www.elsevier.com/locate/b&l Neural responses to morphological, syntactic, and semantic properties of single words: An fMRI study q

suffix priming effects',Language and Cognitive Processes,23:7,1002 — 1020

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Language www.elsevier.com/locate/jml Morphological decomposition and semantic integration in word processing q