Biomedical subjects

Horacio Barber

Publications and source records attributed to Horacio Barber.

7 recordsLinked to original sources

PubMed2005

Grammatical gender and number agreement in Spanish: an ERP comparison.

The role of grammatical gender and number representations in syntactic processes during reading in Spanish was studied using the event-related potentials (ERPs) technique. The electroencephalogram was recorded with a dense array of 128 electrodes while Spanish speakers read word pairs (Experiment 1) or sentences (Experiment 2) in which gender or number agreement relationships were manipulated. Disagreement in word pairs formed by a noun and an adjective (e.g., faro-alto [lighthouse-high]) produced an N400-type effect, while word pairs formed by an article and a noun (e.g., el-piano [the-piano]) showed an additional left anterior negativity effect (LAN). Agreement violations with the same words inserted in sentences (e.g., El piano estaba viejo y desafinado [the (m-s)piano (m-s) was old (m-s) and off-key]) resulted in a pattern of LAN-P600. This effect was found both when the violation occurred in the middle of the sentence (at the adjective), as well as when this happened at the beginning of the sentence (at the noun), but the last segment of the P600 effect was greater for the middle sentence position, which could indicate differences in the complexity of reanalysis processes. Differences between grammatical gender and number disagreement were found in late measures. In the word pairs experiment, P3 peak latency varied across conditions, being later for gender than for number disagreement. Similarly, in the sentence experiment, the last segment of the P600 effect was greater for gender than for number violations. These event-related potentials (ERPs) effects lend support to the idea that reanalysis or repair processes after grammatical disagreement detection could involve more steps in the case of gender disagreement, as grammatical gender is a feature of the lexical representation in contrast to number, which is considered a morphological feature that combines with the stem of the word.

Analysis of Variance↗

PubMed2005

Early event-related potential effects of syllabic processing during visual word recognition.

A number of behavioral studies have suggested that syllables might play an important role in visual word recognition in some languages. We report two event-related potential (ERP) experiments using a new paradigm showing that syllabic units modulate early ERP components. In Experiment 1, words and pseudowords were presented visually and colored so that there was a match or a mismatch between the syllable boundaries and the color boundaries. The results showed color-syllable congruency effects in the time window of the P200. Lexicality modulated the N400 amplitude, but no effects of this variable were obtained at the P200 window. In Experiment 2, high- and low-frequency words and pseudowords were presented in the congruent and incongruent conditions. The results again showed congruency effects at the P200 for low-frequency words and pseudowords, but not for high-frequency words. Lexicality and lexical frequency effects showed up at the N400 component. The results suggest a dissociation between syllabic and lexical effects with important consequences for models of visual word recognition.

Adult↗

PubMed2004

Syllable-frequency effects in visual word recognition: evidence from ERPs.

A lexical decision experiment was conducted while event related potentials (ERPs) were recorded. The word frequency and the first syllable frequency of each word were manipulated. Results showed that, while high frequency words produced less negative amplitudes in the N400 time window than low frequency words, the inverse pattern was found for syllable frequency. Words containing high frequency syllables produced more negative amplitudes than words containing low frequency syllables. Importantly, a significant syllable frequency effect was also obtained at the P200 time window. The results are interpreted in the framework of an interactive activation model, in which high frequency syllables produce the initial activation of a larger number of lexical candidates during the analysis of orthographic or phonological representations, which have to be inhibited later to allow the identification of a unique word. These findings support the idea that, at least in languages with clear syllabic boundaries, syllables are functional sublexical units during visual word recognition.

Adolescent↗

PubMed2004

Event-related potentials elicited during parsing of ambiguous relative clauses in Spanish.

Previous behavioural studies in Spanish have found a significant preference for attaching relative clauses preceded by a complex NP (N1 of N2 RC) to the first noun phrase. In the present study, we used event-related potentials (ERPs) to help identify the nature of these processes by directly comparing ERPs to temporary ambiguous sentences containing relative clauses that were finally consistent with either high or low attachment resolution. The larger amplitude of the P600 effect for the low attachment condition suggests that high attachment was the preferred strategy. The P600 effect was widely distributed in the 500-700 ms window, including frontal areas, while the distribution was mainly posterior in the 700-1000 ms window. The results indicate that high attachment is the parsing strategy Spanish readers use for this type of ambiguity and suggest that the P600 may not be a monolithic effect.

Adolescent↗

PubMed2004

Event-related brain potentials elicited by morphological, homographic, orthographic, and semantic priming.

The morphological structure of words, in terms of their stem morphemes and affixes, could influence word access and representation in lexical memory. Three experiments were carried out to explore the attributes of event-related potentials evoked by different types of priming. Morphological priming, with pairs of words related by their stem (hijo/hija [ son/ daughter]), produced a sustained attenuation (and even a tendency to positivity) of the N400 shown by unrelated words across the three experiments. Homographic priming (Experiment 1), using pairs of words with a superficially similar stem, but without morphological or semantic relation (foco/foca [floodlight/seal]), produced an initial attenuation similar to the morphological pairs, but which rapidly tended to form a delayed N400, due to the impossibility of integration. However, orthographic priming (rasa/rana [flat/frog]) in Experiment 2 does not produce attenuation of the N400 but an effect similar to that of unrelated pairs. Experiment 3 shows that synonyms advance more slowly than morphological pairs to meaning coherence, but finally produce a more positive peak around 600 msec.

Acoustic Stimulation↗

PubMed2003

Integrating gender and number information in Spanish word pairs: an ERP study.

The aim of the current study was to explore the integration processes of gender and number morphological features, since it has been proposed that grammatical gender and number features might be associated with different strength with the word stem in lexical representation. Event related potentials (ERPs) were recorded using a 128-channel sensor net while twenty-four volunteers read Spanish word pairs and performed a syntactic judgment task. The word pairs which could agree or disagree in gender or number or in gender and number at the same time, were formed by a noun and an adjective (e.g. faro-alto [lighthouse-high]). A negativity around 400 msec with posterior distribution, which has been related to lexical integration processes, was found in response to both gender and number violations. No differences were found between gender disagreement, number disagreement and the double disagreement. Therefore, ERPs suggest that integration of gender and number features may not be different, and that the detection of disagreement may work under a binary state, since the double disagreement condition did not differ from the others. In addition, a subsequent component (identified as P3) showed delayed latencies in the gender disagreement condition as compared to the number disagreement condition, while the double disagreement conditions showed a shorter peak latency than the other two disagreement conditions and similar to the agreement condition. The variations in the latency of the P3 component, which has been related to categorization processes, suggest that these processes are quickly triggered by the accumulation of two incongruent as compared to one disagreement features, and that reanalysis is costlier in the case of gender disagreement as compared to the number disagreement.

Adult↗

PubMed2002

Human brain potentials indicate morphological decomposition in visual word recognition.

Stem homographs are pairs of words with the same orthographic description of their stem but which are semantically and morphologically unrelated (e.g. in Spanish: rata/rato (rat/moment)). In priming tasks, stem homographs produce inhibition, unlike morphologically related words (loca/loco (madwoman/madman)) which produce facilitation. An event-related potentials study was conducted to compare morphological and stem homographic priming effects. The results show a similar attenuation of the N400 component at the 350-500 ms temporal window for the two conditions. In contrast, a broad negativity occurs only for stem homographs at the 500-600 ms window. This late negativity is interpreted as the consequence of an inhibitory effect for stem homographs that delays the stage of meaning integration.

Adult↗