An ER-fMRI study of Russian verb morphology

The generation of regular and irregular past tense verbs has long been a testing ground for different models of inflection in the mental lexicon. According to the dual-system view, regular forms are generated by a rule and irregular forms are retrieved from memory. The single-system view postulates a single integrated system for all forms. Behavioral studies examined a variety of languages, but neuroimaging studies still rely almost exclusively on English and German data. We used Russian, a language with a much more complex verb class system. To avoid problems identified in earlier studies, we randomly mixed different tasks (inflecting nonce and real verbs and nouns of different types) and compiled large sets of stimuli matched for frequency and phonological complexity. Unlike most previously obtained results, our findings are more readily compatible with the single-system approach. Observed activation patterns are best explained by the difference in processing load between experimental tasks.