Increasing expertise to a novel script modulates the visual N1 ERP in healthy adults

Abstract

Neural tuning to print develops when children learn to read and is reflected by a more pronounced left occipito-temporal negativity to orthographic stimuli as compared to non-orthographic false fonts or symbols after around 150–250 ms in their N1, a visual event-related potential (ERP). In adults, initial expertise for a novel script can emerge in less than 2 hours through repeated exposure or training. Here, we aimed to assess changes in the visual N1 related to the process of learning associations between unknown written characters and familiar, spoken syllables or words. Thirty-two healthy literate adults learned to associate a set of foreign characters with either syllables or German words within a single experimental session. EEG was recorded during a visual one-back character repetition detection task in which trained characters, untrained characters and familiar letters were presented before and after the training. A bilateral occipito-temporal increase in the N1 negativity with training was only found for the newly learned characters, but not for the control characters. In conclusion, the present data indicate that expertise to novel characters can be induced by a short character–sound association training and is reflected by a bilateral modulation of the visual N1 amplitude. However, no differentiation was found regarding the comparison of word or syllable training, indicating that the visual N1 most likely reflects gaining expertise driven by phonological associations common to both training types.