Journal of Neurolinguistics最新文献

Most neurobiological models of spoken word production propose that multiple lexical candidates are activated in left posterior temporal cortex during word retrieval. Some accounts also propose a role for the left inferior frontal gyrus (LIFG) in selecting the correct word from among these candidates. Evidence for both proposals has come from the picture-word interference (PWI) paradigm, in which participants name pictures (e.g., RABBIT) while ignoring a distractor word. Categorically related distractors (e.g., horse-RABBIT) slow naming latencies compared to unrelated words (e.g., violin-RABBIT), an effect known as semantic interference, whereas congruent distractors (e.g., rabbit-RABBIT) facilitate naming, but the precise conditions in which these effects occur remain a matter of debate. Although the neuroimaging evidence for left temporal cortex engagement in this paradigm is robust, the evidence for LIFG involvement is more equivocal, particularly for semantic interference. A key factor distinguishing LIFG involvement in neuroimaging studies is distractor modality, i.e., activity is more consistently reported for auditory distractors. We therefore applied online anodal transcranial Direct Current Stimulation (atDCS) to LIFG and left posterior temporal cortex in a three-way, cross-over, sham-controlled PWI paradigm involving either written (Experiment 1) or auditory (Experiment 2) distractors. Surprisingly, compared to sham, atDCS over posterior temporal cortex significantly slowed the congruent facilitation effect with written distractors, but did not modulate the semantic interference effect, while atDCS to LIFG did not significantly influence either effect. We also failed to observe any significant modulatory effects of atDCS with auditory distractors. The present results only partially support left temporal lobe engagement during PWI and provide no evidence for LIFG involvement. We recommend future PWI studies systematically investigate different electrode montages in tDCS protocols.

The word stem is distinguished as the core component in verb inflections that envelopes essential semantic and syntactic properties, playing a central role in word processing. In the present study, in order to find the role of form and meaning during the visual recognition of morphologically complex words, the effect of the stem length of inflected Korean verbs was examined in an event-related potential (ERP) lexical decision experiment. Additionally, a potential modulation of whole-word frequency in morphological effect was investigated in order to locate the temporal locus of sublexical (i.e., morphological) and lexico-semantic processing. Behavioral results showed that lexical decision times were faster for targets with shorter stem length compared to targets with identical word length but longer stem length. A significant interaction between the whole-word frequency and stem length was also found, in which stem length effect was not significant in words with high frequency. The ERP data revealed corollary results; the frequency effect emerged as early as N100, followed by significant modulations of N250, N400, and P600 components. The stem length effect was demonstrated in latency ranges N250, N400, and N400. In the N400 component, the interaction of two factors was revealed in which stem length effect shown only in the medium- and low-word frequency levels, but not in the high-frequency level. Taken together, the present data provide evidence for simultaneous activation of morphological and lexico-semantic information in early visual word processing after scanning the whole-form of a word. The results are discussed in terms of the current models of morphologically complex word processing.

Studies of word class processing have found verb retrieval impairments in individuals with primary progressive aphasia (Bak et al., 2001; Cappa et al., 1998; Cotelli et al., 2006; Hillis, Heidler-Gary, et al., 2006; Hillis, Oh, & Ken, 2004; Marcotte et al., 2014; Rhee, Antiquena, & Grossman, 2001; Silveri & Ciccarelli, 2007; Thompson, Lukic, et al., 2012) associated primarily with the agrammatic variant. However, fewer studies have focused on verb comprehension, with inconsistent results. Because verbs are critical to both production and comprehension of clauses and sentences, we investigated verb processing across domains in agrammatic, logopenic, and semantic PPA and a group of age-matched healthy controls. Participants completed a confrontation naming task for verb production and an eye-tracking word-picture matching task for online verb comprehension. All PPA groups showed impaired verb production and comprehension relative to healthy controls. Most notably, the PPA-S group performed more poorly than the other two PPA variants in both domains. Overall, the results indicate that semantic deficits in the PPA-S extend beyond object knowledge to verbs as well, adding to our knowledge concerning the nature of the language deficits in the three variants of primary progressive aphasia.

During conversation, comprehenders often make pragmatic inferences, or implicatures. Our study concerns ad-hoc implicatures, which are quantity-based implicatures. For example, the sentence “I walked Lassie”, where the addressee knows that the speaker has 2 dogs, signals to the addressee that the speaker wanted to convey an enriched meaning (i.e., she walked Lassie, but not the other dog). On some accounts, it is assumed that these implicatures are derived similarly to the well-studied scalar implicatures. Yet, ad-hoc implicatures received little attention. In the current study, we used fMRI to further uncover the mechanisms that support pragmatic inferences, and specifically ad-hoc implicatures. In our judgment task, we first presented a context picture with several objects, then the target sentence (sans picture) which referred to either the subset (implicature condition) or the whole set of objects (no-implicature condition), and finally asked participants to judge whether a final picture matched the target sentence. Comparing the implicature and no-implicature conditions, we observed activations in the rostrolateral prefrontal cortex, which we linked to inference generation, and in the right inferior parietal lobule, which we linked to theory of mind or attention shift. We also performed an ROI analysis, examining activations related to ad-hoc implicatures in regions previously linked to scalar implicatures and to other types of context-based implicatures, showing overlaps and dissimilarities in both cases. Thus, our results are not completely in line with theories that argue for one type of processing in the derivation of pragmatic inferences.