Cognition Research Today is a free monthly online journal that collates and summarizes the latest research about Cognition, including details on psychology, neuroscience, memory, brain theory.

Separate conflict-specific cognitive control mechanisms in the human brain.

Egner T, Delano M, Hirsch J

Functional MRI Research Center, Neurological Institute Box 108, Columbia University, 710 W 168th St, New York, NY 10032, USA. t-egner@northwestern.edu

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.

Published 19 March 2007 in Neuroimage, 35(2): 940-8.
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