Separate conflict-specific cognitive control mechanisms in the human brain.
To ensure optimal task performance, the human brain detects and resolves conflict in information processing via a cognitive control system. However, it is not known whether conflict resolution relies on a single central resource of cognitive control, or on a collection of independent control mechanisms that deal with different types of conflict. In order to address this question, we assessed behavioral and blood-oxygen-level-dependent (BOLD) responses during the simultaneous detection and resolution of two sources of conflict in a modified color-naming Stroop task: conflict stemming from incompatibility between the task-relevant and an irrelevant stimulus feature (stimulus-based or Stroop conflict), and conflict stemming from incompatibility between an irrelevant stimulus feature and response features (response-based or Simon conflict). Results show that control mechanisms recruited by stimulus-based conflict resolve stimulus-based conflict, but do not affect the resolution of response-based conflict, and vice versa. The resolution of response-based conflict was distinguished by modulation of activity in premotor cortex, whereas resolution of stimulus-based conflict was distinguished by the modulation of activity in parietal cortex. These results suggest that the human brain flexibly adopts, and independently controls, conflict-specific resolution strategies, biasing motor programming to resolve response-based conflict, and biasing stimulus representations to resolve stimulus-based conflict. We propose a non-centralized, modular architecture of cognitive control, where separate control resources operate in parallel, and are recruited in a context-sensitive manner.
Egner
Tobias
T
Functional MRI Research Center, Neurological Institute Box 108, Columbia University, 710 W 168th St, New York, NY 10032, USA. t-egner@northwestern.edu
Delano
Margaret
M
Hirsch
Joy
J
D000328:Adult; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003220:Conflict, Psychological; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male