FMRI activation in language areas correlates with verb generation performance in children

Functional MRI mapping of language areas in children frequently employs a covert verb generation task. Because responses are not monitored, the relationship between fMRI activation and task performance is unknown. We compared fMRI activation during covert and overt verb generation to performance during the overt task. 15 children, ages 11-13 years, listened to concrete nouns and responded with related verbs covertly and overtly. A clustered fMRI acquisition allowed for recording of overt responses without motion artifacts. Region of interest analysis was also performed in areas that exhibited correlation between activation and performance during overt verb generation in left inferior frontal and left superior temporal gyri (along with their right hemisphere homologues). Regression analysis determined that during both covert and overt generation, left hemisphere regions showed positive correlations with average counts of verbs generated during the overt task. These results suggest that increased verb generation performance leads to increased activation. In addition, overt performance may be used as an estimator of covert performance.