Biomedical subjects

Liina Pylkkänen

Publications and source records attributed to Liina Pylkkänen.

5 recordsLinked to original sources

PubMed2006

The representation of polysemy: MEG evidence.

Most words in natural language are polysemous, that is, they can be used in more than one way. For example, paper can be used to refer to a substance made out of wood pulp or to a daily publication printed on that substance. Although virtually every sentence contains polysemy, there is little agreement as to how polysemy is represented in the mental lexicon. Do different uses of polysemous words involve access to a single representation or do our minds store distinct representations for each different sense? Here we investigated priming between senses with a combination of behavioral and magnetoencephalographic measures in order to test whether different senses of the same word involve identity or mere formal and semantic similarity. Our results show that polysemy effects are clearly distinct from similarity effects bilaterally. In the left hemisphere, sense-relatedness elicited shorter latencies of the M350 source, which has been hypothesized to index lexical activation. Concurrent activity in the right hemisphere, on the other hand, peaked later for sense-related than for unrelated target stimuli, suggesting competition between related senses. The obtained pattern of results supports models in which the representation of polysemy involves both representational identity and difference: Related senses connect to same abstract lexical representation, but are distinctly listed within that representation.

Adolescent↗

PubMed2006

A time course analysis of enriched composition.

Linguistic analyses suggest that common and seemingly simple expressions, such as began the book, cannot be interpreted with simple compositional processes; rather, they require enriched composition to provide an interpretation, such as began reading the book (Jackendoff, 1997; Pustejovsky, 1995). Recent reading time studies have supported these accounts by providing evidence that these expressions are more costly to process than are minimally contrasting controls (e.g., McElree, Traxler, Pickering, Seely, and Jackendoff, 2001). We report a response signal speed-accuracy trade-off (SAT) study in which two types of expressions that are thought to require enriched composition were examined. Analyses of the full time course SAT data indicate that these expressions were interpreted less accurately and, most importantly, more slowly than control sentences. The latter finding suggests that enriched composition requires the online deployment of complex compositional operations.

Comprehension↗

PubMed2004

Neural correlates of the effects of morphological family frequency and family size: an MEG study.

Schreuder and Baayen (Schreuder. R., & Baayen, R. H. (1997). How complex simplex words can be. Journal of Memory and Language 37, 118-139) report that lexical decision times to nouns are not sensitive to the cumulative frequency of the noun's morphological derivatives in its "morphological family", even though such a cumulative frequency effect is obtained in the domain of inflection. Under a decomposition view of derivational morphology, this constitutes a puzzling exception to the robust finding that lexical frequency is one of the major determinants of behavioral response latencies. If morphologically complex words are decomposed, each occurrence of a member of a noun's morphological family should add to its root-frequency. We investigated the effects of morphological family frequency on the magnetoencephalographic response component M350, which shows sensitivity to factors affecting early stages of lexical processing, including lexical frequency. We hypothesized that high morphological family frequency should have a facilitory effect on the M350, even though no such effect can be seen in response time, presumably due to competition among possible root-affix combinations. Contrary to this hypothesis, we found that high family frequency elicits an M350 inhibition, suggesting that competition among morphological family members occurs at the M350. The result is significant, since there is evidence that competition among phonologically similar words occurs after, not at, the M350. Thus, our results suggest that competition within a morphological family precedes competition within a phonological similarity neighborhood.

Adult↗

PubMed2003

Tracking the time course of word recognition with MEG.

Twenty years ago it was discovered that recognition of semantically unexpected words is associated with a special ERP signature - the N400. Pinpointing the precise functional significance of the N400 has, however, been difficult. Recent MEG studies of word processing reveal that, in fact, the N400 decomposes into several functionally distinct subcomponents, allowing for more fine-grained investigation of its significance.

Journal Article↗

PubMedDate not supplied

Neuromagnetic evidence for the timing of lexical activation: an MEG component sensitive to phonotactic probability but not to neighborhood density.

Evidence from electrophysiological measures such as ERPs (event-related potentials) and MEG (magnetoencephalography) suggest that the first evoked brain response component sensitive to stimulus properties affecting reaction times in word recognition tasks occurs at 300-400 ms. The present study used the stimulus manipulation of Vitevich and Luce (1999) to investigate whether the M350, an MEG response component peaking at 300-400 ms, reflects lexical or postlexical processing. Stimuli were simultaneously varied in phonotactic probability, which facilitates lexical activation, and in phonological neighborhood density, which inhibits the lexical decision process. The present results indicate that the M350 shows facilitation by phonotactic probability rather than inhibition by neighborhood density. Thus the M350 cannot be a postlexical component.

Adult↗