Manipulating visual, rule and motor conflict partially dissociates multiple demand cortex sub-regions

Flexible behaviour requires cognitive-control mechanisms to efficiently mediate conflict between competing information and alternative actions. Whether a global neural resource mediates all forms of conflict or this is achieved within domain-specific systems remains unclear. We use a novel fMRI paradigm to orthogonally manipulate rule, response and stimulus-based conflict within a full-factorial design. Whole-brain voxelwise analyses show that activation patterns associated with these conflict types are distinct, but they partially overlap within the Multiple Demand Cortex (MDC) regions that are most commonly active during cognitive tasks. Region of interest analysis shows that most MDC sub-regions are activated for all conflict types, but to significantly varying levels. We propose that conflict resolution is an emergent property of distributed brain networks, the functional-anatomical components of which place on a continuous, not categorical, scale from domain-specialised to domain general. MDC brain regions place towards one end of that scale but still exhibit significant functional heterogeneity.