Referent's Lexical Frequency Predicts Mismatch Negativity Responses to New Words Following Semantic Training.

Lexical ERPs (event-related potentials) obtained in an oddball paradigm were suggested to be an index of the formation of new word representations in the brain in the learning process: with increased exposure to new lexemes, the ERP amplitude grows, which is interpreted as a signature of a new memory-trace build-up and activation. Previous learning studies using this approach have, however, mostly used meaningless novel word forms; it therefore remains uncertain whether the increased amplitude simply reflects increased familiarity with the new stimulus or is indeed a reflection of a complete word representation. Here, we used the oddball paradigm to measure the mismatch negativity (MMN) responses to novel word forms before and after semantic training, during which they were associated with previously familiar words of either high or low frequency of occurrence.