Early occipital sensitivity to syntactic category is based on form typicality

Syntactic factors can rapidly affect behavioral and neural responses during language processing; however, the mechanisms that allow this rapid extraction of syntactically relevant information remain poorly understood. We addressed this issue using magnetoencephalography and found that an unexpected word category (e.g., “The recently princess . . . ”) elicits enhanced activity in visual cortex as early as 120 ms after exposure, and that this activity occurs as a function of the compatibility of a word’s form with the form properties associated with a predicted word category. Because no sensitivity to linguistic factors has been previously reported for words in isolation at this stage of visual analysis, we propose that predictions about upcoming syntactic categories are translated into form-based estimates, which are made available to sensory cortices. This finding may be a key component to elucidating the mechanisms that allow the extreme rapidity and efficiency of language comprehension

Sensibilidade do componente n170 à natureza ortográfica do estímulo

Dissertação de mestrado, Neurociências Cognitivas e Neuropsicologia, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2017O sistema visual dos indivíduos letrados possui expertise no reconhecimento visual de palavras, indicando que o ser humano processa a palavra escrita de uma maneira distinta e mais específica do que outros estímulos visuais (McCandliss, Cohen, & Dehaene, 2003). Esta expertise do sistema visual manifesta-se através um pico de atividade eletrofisiológica que surge cerca de 170ms após a apresentação do estímulo visual (o N170), que é considerada uma resposta cerebral específica ao código ortográfico (coarse tuning to print) e que tem sido usado como marcador neuronal da experiência de leitura. Neste estudo pretende-se averiguar se, em leitores experientes, o N170 é sensível a características pós-lexicais do estímulo ortográfico, nomeadamente o seu estatuto lexical (palavra versus pseudopalavra) e sua consistência grafema-fonema, e se essa sensibilidade depende do nível de competência de leitura. Participaram neste estudo 42 sujeitos adultos (30 do sexo feminino, idades entre 17 e 32 anos, escolaridade ao nível do Ensino Superior), tendo sido registada a sua atividade elétrica cerebral durante uma prova de leitura implícita. Os resultados obtidos mostram um forte efeito de hemisfério em que a amplitude do N170 é maior no hemisfério esquerdo e um efeito de consistência moderadamente significativo onde a amplitude do N170 é maior em palavras onde existe consistência grafema-fonema. Foi ainda apurado um efeito de lexicalidade significativo. Por fim, a perícia de leitura parece não estar associada à magnitude do componente N170

Early lexical processing of Chinese one-character words and Mongolian words: A comparative study using event-related potentials

Logographic language and alphabetic language differ significantly in orthography. Investigating the commonality and particularity of visual word recognition between the two distinct writing systems is informative for understating the neural mechanisms underlying visual word recognition. In the present study, we compared the chronometry of early lexical processing and the brain regions involved in early lexical processing between Chinese (logographic language) and Mongolian (alphabetic language) by recording event-related potentials (ERPs) using both implicit and explicit reading tasks. Familiar Chinese one-character words (lexical) and unknown Chinese one-character words (non-lexical) were pseudorandomly presented to native Chinese readers in Experiment 1. Mongolian words (lexical) and pseudowords (non-lexical) were pseudorandomly presented to native Mongolian readers in Experiment 2. In the color decision task, participants were asked to decide the color (black or blue) of each stimulus. In the lexical recognition task, participants were asked to report whether they could recognize each stimulus. The results showed that in both experiments and both tasks, ERPs to lexical items differed significantly from those to non-lexical items in the parietooccipital scalp region approximately 250 ms after stimulus onset, reflecting the early lexical processing, which likely originated from the ventral occipitotemporal cortex as revealed by source analysis. These results indicated that although Chinese and Mongolian differed markedly in orthographic features, the neural mechanisms underlying early lexical processing are similar between the two languages

The time course of processing handwritten words: An ERP investigation

Behavioral studies have shown that the legibility of handwritten script hinders visual word recognition. Furthermore, when compared with printed words, lexical effects (e.g., word-frequency effect) are magnified for less intelligible (difficult) handwriting (Barnhart & Goldinger, 2010; Perea et al., 2016). This boost has been interpreted in terms of greater influence of top-down mechanisms during visual word recognition. In the present experiment, we registered the participants' ERPs to uncover top-down processing effects on early perceptual encoding. Participants' behavioral and EEG responses were recorded to high- and low-frequency words that varied in script's legibility (printed, easy handwritten, difficult handwritten) in a lexical decision experiment. Behavioral results replicated previous findings: word-frequency effects were larger in difficult handwriting than in easy handwritten or printed conditions. Critically, the ERP data showed an early effect of word-frequency in the N170 that was restricted to the difficult-to-read handwritten condition. These results are interpreted in terms of increased attentional deployment when the bottom-up signal is weak (difficult handwritten stimuli). This attentional boost would enhance top-down effects (e.g., lexical effects) in the early stages of visual word processing

Orthografische Verarbeitung bei Kindern mit Lese- und/oder Rechtschreibstörung: Neurophysiologische Korrelate und Lernprozesse

Die Forschung zu den schulischen Lernstörung ging bisher von einem Störungskonzept, der Legasthenie, aus, mit dem die Probleme im Lesen und Rechtschreiben zusammengefasst wurden. Die aktuelle Forschung aber zeigte, dass sich drei Störungen schulischer Lernstö-rungen abgrenzen lassen, nämlich eine Lese-, eine Rechtschreib-, und eine Lese- und Recht-schreibstörung. Diese Unterteilung wurde sowohl in epidemiologischen Studien als auch in den Studien zu den Ursachen dieser Störungen bestätigt. Letztendlich unterscheidet auch das DSM-5 zwischen Lese- und Rechtschreibstörung. Unklar bisher aber ist, was sind die neu-rokognitiven und neurophysiologischen Korrelate, die diese Lernstörungsgruppen unter-scheiden. Es wird vermutet, dass die Probleme im Rechtschreiben (Rechtschreibstörung) und Lesen (Lesestörung) auf Unterschiede in der orthografischen Verarbeitung zurückzuführen sind. Um die Dissoziationen besser verstehen zu können, wurden Kinder mit isolierten Lese-, isolierten Rechtschreib- und kombinierten Lese- und Rechtschreibstörungen mit Kindern ohne Probleme im Schriftspracherwerb (Kontrollgruppe) sowohl in ihrer Leistung beim Ler-nen neuer Wörter (orthografisches Lernen) als auch hinsichtlich der neurophysiologischen Aktivierung bei der automatischen orthografischen Wortverarbeitung verglichen. Die Ergebnisse im Hinblick auf das orthografische Lernen zeigten, dass Kinder mit isolierter Lesestörung keine Schwierigkeiten im kurzzeitigen Merken und im Einspeichern orthografi-scher Repräsentationen im Langzeitgedächtnis hatten. Kinder mit Lesestörung zeigten aller-dings ein verlangsamtes Lesetempo, welches auf einen verzögerten Zugriff oder eine längere Verarbeitungsdauer der gespeicherten Repräsentationen zurückzuführen sein könnte. Kinder mit isolierter Rechtschreibstörung hingegen scheinen Probleme beim Einspeichern spezifi-scher Wortbilder inklusive der orthografischen Marker im Langzeitgedächtnis zu haben. Im Hinblick auf die automatische orthografische Verarbeitung von Wörtern zeigten die Kinder aller Gruppen den „word superiority effect“ (ein Buchstabe wird besser erkannt, wenn er zuvor in einem sehr kurz präsentierten Wort eingebettet ist im Vergleich zu einem Nichtwort) sowohl auf Verhaltens- als auch auf neurophysiologischer Ebene. Unterschiede zeigten sich bei der neurophysiologischen Aktivierung der N400-Amplitude (EKP-Komponente) hin-sichtlich der phonologischen Wortverarbeitung. Kinder mit isolierten Lesedefiziten zeigten keine Probleme in der phonologischen Wortverarbeitung (gleiche Aktivierungsunterschiede wie die Kontrollgruppe), während Kinder mit isolierten Rechtschreibdefiziten eine reduzierte Sensitivität bei der phonologischen Wortverarbeitung zeigten (keine Unterschiede in der N400-Aktivierung). Dissoziationen zwischen Lese- und Rechtschreibstörungen sind dem-nach mit Unterschieden sowohl im orthografischen Lernen als auch in der automatischen orthografischen Wortverarbeitung verbunden.Current research has shown that learning disorders can be distinguished between reading, spelling und combined reading and spelling disorders. Isolated reading and isolated spelling deficits are as frequent as combined reading and spelling disorders. It is unclear what underlying neurocognitive and neurophysiological deficits are likely to be associated with dissociations between reading and spelling. It is suggested that problems in spelling and reading are probably due to distinct deficits in orthographic word processing. To better understand these dissociations, children with isolated reading fluency deficits, isolated spelling deficits, and combined reading and spelling deficits were compared to children with age appropriate reading and spelling skills (controls), both in their performance in learning new words (orthographic learning) and in their neurophysiological activation of automatic orthographic word processing. The results in terms of orthographic learning showed that children with isolated deficits in reading had no problems in storing orthographic representations in long-term memory. The data suggest that the dysfluent reading of children with isolated reading fluency deficits is probably due to a disrupted or slowed down access to the stored intact representations. Children with isolated spelling deficits, on the other hand, seem to have problems in storing precise representations in long-term memory. With regard to automatic orthographic processing of words, the children of all groups showed a “word superiority effect” (a letter is better identified if it is embedded in a very briefly presented word in comparison to a nonword), both on the behavioral and the neuro-physiological level. Group differences occurred in the N400 activation regarding phono-logical processing. Children with isolated reading deficits showed no problems in phonological word processing (same differences in N400 activation as controls), while children with isolated spelling deficits seem to have a reduced sensitivity for phonological word processing (missing N400 activation differences). In sum, dissociations between reading and spelling problems are associated with differences, both in orthographic learning and automatic orthographic word processing

A normative study of acronyms and acronym naming

Acronyms are an idiosyncratic part of our everyday vocabulary. Research in word processing has used acronyms as a tool to answer fundamental questions such as the nature of the word superiority effect (WSE) or which is the best way to account for word-reading processes. In this study, acronym naming was assessed by looking at the influence that a number of variables known to affect mainstream word processing has had in acronym naming. The nature of the effect of these factors on acronym naming was examined using a multilevel regression analysis. First, 146 acronyms were described in terms of their age of acquisition, bigram and trigram frequencies, imageability, number of orthographic neighbors, frequency, orthographic and phonological length, print-to-pronunciation patterns, and voicing characteristics. Naming times were influenced by lexical and sublexical factors, indicating that acronym naming is a complex process affected by more variables than those previously considered

Sensitivity to syntax in visual cortex

One of the most intriguing findings on language comprehension is that violations of syntactic predictions can affect event-related potentials as early as 120 ms, in the same time-window as early sensory processing. This effect, the so-called early left-anterior negativity (ELAN), has been argued to reflect word category access and initial syntactic structure building (Friederici, 2002). In two experiments, we used magnetoencephalography to investigate whether (a) rapid word category identification relies on overt category-marking closed-class morphemes and (b) whether violations of word category predictions affect modality-specific sensory responses. Participants read sentences containing violations of word category predictions. Unexpected items varied in whether or not their word category was marked by an overt function morpheme. In Experiment 1, the amplitude of the visual evoked M100 component was increased for unexpected items, but only when word category was overtly marked by a function morpheme. Dipole modeling localized the generator of this effect to the occipital cortex. Experiment 2 replicated the main results of Experiment 1 and eliminated two non-morphology-related explanations of the M100 contrast we observed between targets containing overt category-marking and targets that lacked such morphology. Our results show that during reading, syntactically relevant cues in the input can affect activity in occipital regions at around 125 ms, a finding that may shed new light on the remarkable rapidity of language processing