Automatic processing of unattended lexical information in visual oddball presentation: neurophysiological evidence

Abstract

Previous electrophysiological studies of automatic language processing revealed early (100–200 ms) reflections of access to lexical characteristics of speech signal using the so-called mismatch negativity (MMN), a negative ERP deflection elicited by infrequent irregularities in unattended repetitive auditory stimulation. In those studies, lexical processing of spoken stimuli became manifest as an enhanced ERP in response to unattended real words, as opposed to phonologically matched but meaningless pseudoword stimuli. This lexical ERP enhancement was explained by automatic activation of word memory traces realized as distributed strongly intra-connected neuronal circuits, whose robustness guarantees memory trace activation even in the absence of attention on spoken input. Such an account would predict the automatic activation of these memory traces upon any presentation of linguistic information, irrespective of the presentation modality. As previous lexical MMN studies exclusively used auditory stimulation, we here adapted the lexical MMN paradigm to investigate early automatic lexical effects in the visual modality. In a visual oddball sequence, matched short word and pseudoword stimuli were presented tachistoscopically in perifoveal area outside the visual focus of attention, as the subjects' attention was concentrated on a concurrent non-linguistic visual dual task in the center of the screen. Using EEG, we found a visual analogue of the lexical ERP enhancement effect, with unattended written words producing larger brain response amplitudes than matched pseudowords, starting at ~100 ms. Furthermore, we also found significant visual MMN, reported here for the first time for unattended perifoveal lexical stimuli. The data suggest early automatic lexical processing of visually presented language which commences rapidly and can take place outside the focus of attention.

Real-time Functional Architecture of Visual Word Recognition

“…Without properly time-resolved processing measures, however, it is not possible to determine how these contexts operate-whether they operate primarily in the second phase domain of morpholexical interpretation, or whether they directly modulate the operations of the orthographic input system. Finally, we note that some findings from EEG and MEG suggest that the initial sweep through the visual word recognition system to the level of lexical access occurs within 200 msec of word onset (e.g., Shtyrov et al, 2013;Lavric et al, 2012;Hauk et al, 2006;Pammer et al, 2004). These timings contrast with this study, where morphological effects emerge at 300 msec and lexicality effects appear later still.…”

“…Early lexical effects, although small relative to later N400 time frames, have been reported in a range of posterior and middle temporal sites. Hauk et al (2012), for example, report word-pseudoword differences for the time period 180-220 msec in left anterior middle and inferior temporal lobes, whereas Shtyrov, Goryainova, Tugin, Ossadtchi, & Shestakova, (2013) observe even earlier lexicality effects (at around 100 msec) in an EEG study using MMN techniques.…”

Brain responses to syntax constrained by time-driven implicit prosodic phrases

“…These connections mediate priming effects reducing the MMN for word combinations that follow syntactic rules, whereas words in ungrammatical sequences are unprimed and produce larger brain responses. The MMN has also been observed for the visual presentation of linguistic material, in which case the negativity elicited by the deviant stimulus had a posterior distribution (Shtyrov, Goryainova, Tugin, Ossadtchi, & Shestakova, 2013).…”

Visual Mismatch Negativity (vMMN): a Prediction Error Signal in the Visual Modality

“…Shtyrov et al (2013) used vMMN to investigate early automatic lexical effects in the visual modality. They presented participants with word and pseudo-word stimuli perifoveally using an oddball design, while participants engaged in a centrally presented task.…”