Abstract
Whether short-term learning of new words can induce rapid changes in cortical areas involved in distributed neural representation of the lexicon is a hotly debated topic. To answer this question, we examined magnetoencephalographic phase-locked responses elicited in the cerebral cortex by passive presentation of eight novel pseudowords before and immediately after an operant conditioning task. This procedure forced participants to perform an active search for unique meaning of four word-forms that referred to movements of their own body parts. While familiarization with novel word-forms led to bilateral repetition suppression of cortical responses to all eight pseudowords, these reduced responses became more selectively tuned towards newly learned action words in the left hemisphere. Our results suggest that stimulus repetition and active learning of semantic association have separable effects on cortical activity. They also evidence rapid plastic changes in cortical representations of meaningful auditory word-forms after active learning.
