Poster #: 109
Topic: Speech and language (incl. deficits)
Wednesday, Sep 9, 2015
Rapid and automatic formation of novel memory traces for visually presented unattended words: MEG evidence
1Center of Functionally Integrative Neuroscience (CFIN)/MINDLab, University of Aarhus, Aarhus C, Denmark
To master a language and communicate effectively, we must acquire large vocabularies. During childhood, words are acquired rapidly, and novel words can be efficiently used already after some dozens of repetitions in active learning tasks. Word learning also occurs in adulthood, and, for spoken words, it can be traced neurophysiologically as a specific increase in oddball ERPs elicited by novel words with native-like phonology, occurring within minutes of passive repetitive exposure to them (Shtyrov et al., J Neursci 2010). It remains unknown, however, whether similar mechanisms exist in visual modality for learning new written words.
To address this, we used MEG and a classical oddball paradigm to present visually, orthographically and phonologically matched known words and novel word forms (“pseudo-words”), tachistoscopically displayed on the visual field periphery to subjects occupied by a central non-linguistic dual colour-detection task. We compared the differences between the temporal dynamics of MEG responses to known words and novel pseudo-words throughout the ~15 minute exposure time. We found a visual analogue of automatic rapid memory trace formation for unattended pseudo-words: a rapid increase in early (~100ms) perisylvian activation in response to novel deviant orthographic stimuli. Our results show, for the first time, rapid build-up of neural memory traces for new visually-presented words. The results suggest a common neural mechanism underpinning “fast mapping” of novel linguistic information, which is shared by auditory and visual modalities.