New insights into the neural basis of cognitive control: An event-related fMRI study of task selection processes

To investigate cognitive control, researchers have repeatedly employed task switching paradigms. The comparison of switch relative to repeat trials reveals longer response times and higher error rates, a pattern that has been interpreted as switching costs. Functional magnetic resonance imaging (fMRI) studies have shown the involvement of different brain modules in switching conditions, including prefrontal and parietal regions together with other sub-cortical structures. In this study, the aim was to shed light on the brain basis of cognitive control using an approach that proved useful in previous studies investigating language control in bilinguals. We examined adult participants in one simple color naming context and two task selection mixed contexts. In the first mixed selection context, participants named the color or the shape of the stimulus based on a cue word. In the second, they named the color or the size of the stimulus. It was assumed that the comparison of brain responses to the same color naming in mixed selection contexts vs. in non-selection context will reveal the of engagement of cognitive control/task selection processes. Whole brain analysis of color naming in the different contexts showed a significant main effect of context. The comparison of brain responses in several frontal, parietal and sub-cortical regions, of which some are supposedly involved in cognitive control, demonstrated an increased activation during color naming in mixed relative the simple non-mixed context. The different cognitive control modules described in this study fit with recent bilingual language control and domain general cognitive models.