A combined ERP and near-infrared spectroscopy study on phonotactic sensitivity

Possible combinations of different phonemes within a word of a specific language are characterized by phonotactic rules. These rules play an important role in both phonology as well as in lexical activation. In the present study we simultaneously measured event-related brain potentials (ERPs) and the cortical oxygenation changes by near-infrared spectroscopy while participants listened to pseudowords which were either phonotactically legal or illegal with respect to German. Illegal ones, however, were controlled for legality with respect to another language, namely Slovak. ERP results showed an N400 effect for legal compared to illegal pseudowords. The neurovascular signals show a stronger left-hemispheric lateralization for legal compared to illegal pseudowords whereas illegal ones result in a stronger right-hemispheric response over temporal regions. The results suggest that pseudowords following the rules of participants` native language recruit language-related neuronal networks, both from an electrophysiological and a vascular perspective, as the familiar phonotactic rules were extracted even from words without any meaning. The present evidence is important with respect to the universality or diversity of phonotactic processing mechanisms across different languages. As little is known about the neurocognitive aspects associated with the acquisition of phonotactic knowledge during infancy, we just conduct the same study in infants below the sixth month of age