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In this event-related potential (ERP) study a masking technique that prevents conscious perception of words and non-words through attentional distraction was used to reveal the temporal dynamics of word processing under non-conscious and conscious conditions. In the non-conscious condition, ERP responses differed between masked words and non-words from 112 to 160 ms after stimulus-onset over posterior brain areas. The early onset of the word-non-word differences was compatible with previous studies that reported non-conscious access to orthographic information within this time period. Moreover, source localisations provided evidence for automatic activation of prelexical phonological information, whereas no evidence for non-conscious semantic processing was found. When subjects were informed about the masking technique, lexical differences occurred at later time intervals, suggesting conscious access to additional word related information. These results indicate that early visual word processing does not depend entirely on attentional resources, but that non-conscious processing probably is restricted to rather lower-level linguistic information., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Event-related potentials (ERPs) were used to trace changes in brain activity related to progress in second language learning. Twelve English-speaking exchange students learning German in Switzerland were recruited. ERPs to visually presented single words from the subjects' native language (English), second language (German) and an unknown language (Romansh) were measured before (day 1) and after (day 2) 5 months of intense German language learning. When comparing ERPs to German words from day 1 and day 2, we found topographic differences between 396 and 540 ms. These differences could be interpreted as a latency shift indicating faster processing of German words on day 2. Source analysis indicated that the topographic differences were accounted for by shorter activation of left inferior frontal gyrus (IFG) on day 2. In ERPs to English words, we found Global Field Power differences between 472 and 644 ms. This may due to memory traces related to English words being less easily activated on day 2. Alternatively, it might reflect the fact that--with German words becoming familiar on day 2--English words loose their oddball character and thus produce a weaker P300-like effect on day 2. In ERPs to Romansh words, no differences were observed. Our results reflect plasticity in the neuronal networks underlying second language acquisition. They indicate that with a higher level of second language proficiency, second language word processing is faster and requires shorter frontal activation. Thus, our results suggest that the reduced IFG activation found in previous fMRI studies might not reflect a generally lower activation but rather a shorter duration of activity.