Miriam Lemle

Discriminating among different types of verb-complement merge in Brazilian Portuguese: an ERP study of morpho-syntactic sub-processes

Abstract Taking into consideration differences in syntactic configurations underlying the verb-complement merge operation, this experiment investigates three series of sentences containing incongruous and congruous merges. The aim is to relate syntactic specificities to the resulting ERP morphologies. Conditions tested required three types of computations: local merge, local merge depending on inheritance of semantic properties from an antecedent and merge performed at distance (WH-displacement). A total of 240 experimental sentences (80 for each condition) and 240 distractor sentences were generated in Brazilian Portuguese. Using a kinetic presentation protocol, sentences were displayed to each of 25 subjects, while the raw EEG was acquired at 20 derivations. Signal processing techniques were used to estimate the individual ERP for each anatomic region. Series 1 involving strictly local computations resulted in classic parietal N400s, whereas the inheritance stimuli elicited two peaks in the parietal and central region ERPs. Series 3—WH-displacement—presented earlier and more salient cortical responses. The different ERP morphologies resulting from each condition are consistent with a model in which language processing results from task-specific computations involving different neurological subsystems.

Statistical analysis of event-related potential elicited by verb-complement merge in Brazilian Portuguese

An interesting fact about language cognition is that stimulation involving incongruence in the merge operation between verb and complement has often been related to a negative event-related potential (ERP) of augmented amplitude and latency of ca. 400 ms - the N400. Using an automatic ERP latency and amplitude estimator to facilitate the recognition of waves with a low signal-to-noise ratio, the objective of the present study was to study the N400 statistically in 24 volunteers. Stimulation consisted of 80 experimental sentences (40 congruous and 40 incongruous), generated in Brazilian Portuguese, involving two distinct local verb-argument combinations (nominal object and pronominal object series). For each volunteer, the EEG was simultaneously acquired at 20 derivations, topographically localized according to the 10-20 International System. A computerized routine for automatic N400-peak marking (based on the ascendant zero-cross of the first waveform derivative) was applied to the estimated individual ERP waveform for congruous and incongruous sentences in both series for all ERP topographic derivations. Peak-to-peak N400 amplitude was significantly augmented (P < 0.05; one-sided Wilcoxon signed-rank test) due to incongruence in derivations F3, T3, C3, Cz, T5, P3, Pz, and P4 for nominal object series and in P3, Pz and P4 for pronominal object series. The results also indicated high inter-individual variability in ERP waveforms, suggesting that the usual procedure of grand averaging might not be considered a generally adequate approach. Hence, signal processing statistical techniques should be applied in neurolinguistic ERP studies allowing waveform analysis with low signal-to-noise ratio.

Inserção lexical ou envoltório lexical

Na analise comparativa das estruturas argumentais de verbos observadas no seu puro esqueleto, a semelhanca entre diferentes linguas predomina. Contudo, ao se focalizarem verbos cognatos individuais resultam desencontros: para verbos com o mesmo rotulo fonologico, ha estruturas que uma lingua aproveita e a outra nao. A explicacao dessa falta de identidade no espelhamento precisa provir da leitura sintaticamente contextualizada da raiz: os falantes de diferentes linguas podem optar por diferentes leituras para as mesmas formas fonologicas nos mesmos contextos. Podem tambem dar rotulos fonologicos diferentes para ‘os mesmos eventos’ no mundo. Neste artigo pretendemos ilustrar dois fenomenos de interface sintaxe-semântica: a falta de isomorfia perfeita entre estruturas sintaticas e a sua leitura, com dados de reanalises de participios, sufixos e prefixos; e realocacoes de raizes em contextos sintaticos de verbos. A razao de ser da imperfeicao na correspondencia sintaxe-semântica esta no fato de que a estrutura sintatica nao e determinada por saberes extralinguisticos.