fMRI Study of Development in Stroop Color-Word Task
The cognitive processes underlying the Stroop task (i.e. response inhibition, interference resolution, and behavioral conflict resolution) are considered executive processes mediated by the frontal lobe.
We used the classic Stroop interference task with fMRI to investigate neuromaturational processes underlying cognitive development in individuals ranging in age from early childhood to young adulthood.
Stroop imaging studies with adults have shown brain activation in activation in the right middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), left parietal region, and left insula.
In accord with past Stroop task neuroimaging research, we hypothesized that development of executive processes involved in the Stroop interference process would be localized to these regions.
fMRI was used to determine developmental changes in brain activation during a Stroop color-word interference task from 30 subjects (10 M/20 F) in three age groups: children (aged 7-11, 3M/5F), adolescents (aged 12-16, 4M/7F), and young adults (aged 18-22, 3M/8F).
Figure shows brain regions with significant (p<0.05) Stroop task-related activation in the young adult group.
fMRI activation superimposed on average of T1-weighted images from 29 normal individuals (10 M, 19 F) normalized to Talairach space.
In young adults, Stroop task activates:
Middle and inferior frontal gyrus
Inferior and superior parietal lobe
Superior/medical occipital gyrus
Figure shows brain areas in which Stroop significantly (p<0.05) correlated with age. fMRI activation superimposed on average of T1-weighted images from 29 normal individuals.
A positive correlation was observed between age and Stroop-related activation in the left lateral prefrontal cortex, the left anterior cingulate, and the left parietal and parieto-occipital cortices.
Young adults>>adolescents activation in left middle frontal gyrus.
Young adults>>children activation in anterior cingulate and left parietal, parieto-occipital regions, left middle frontal gyrus.
Young adults and adolescents, but not children, showed activation in parietal cortex.
Stroop task-related functional development of parietal lobe occurs by adolescence. Prefrontal cortex function, however, develops into adulthood. These findings provide a template for assessing normal development and neurodevelopmental disorders.