Two different brain networks underlying picture naming with familiar pre-existing native words and new vocabulary.

The present research used fMRI to longitudinally investigate the impact of learning new vocabulary on the activation pattern of the language control network by measuring BOLD signal changes during picture naming tasks with familiar pre-existing native words (old words) and new vocabulary. Nineteen healthy participants successfully learned new synonyms for already known Spanish words, and they performed a picture naming task using the old words and the new words immediately after learning and two weeks after learning. The results showed that naming with old words, compared to naming with newly learned words, produced activations in a cortical network involving frontal and parietal regions, whereas the opposite contrast showed activation in a broader cortical/subcortical network, including the SMA/ACC, the hippocampus, and the midbrain. These two networks are maintained two weeks after learning. These results suggest that the language control network can be separated into two functional circuits for diverse cognitive purposes.