Synthetic Brain Imaging of English Past Tense Inflection

Brain imaging studies of English past tense inflection have found dissociations between regular and irregular verbs, but no coherent picture has emerged to explain how these dissociations arise. Here we use synthetic brain imaging on a neural network model to provide a mechanistic account of how regional dissociations between regular and irregular processing in adults can emerge in a single mechanism system with experience-dependent structural development. We show that these dissociations arise from a combination of different statistical properties of verbs relating to frequency, relationships to other verbs, and phonological complexity. The model generates predictions about the patterning of active brain regions for different verbs that can be tested in future brain imaging studies.