Visual cortex activity reflects modulations of distracter suppression driven by conflict probability and correlates with reactive adjustments in attentional control in the frontal cortex. A, Event-related brain activity evoked by distracter-present trials in retinotopic regions of the visual cortex that spatiotopically represent distracters (as identified by “distracter > target” contrast in the functional localizer run). The contrast “distracter > target in 20% Inc blocks versus in 60% Inc blocks” is represented here. Several regions of the visual cortex, including ventral V1, V2, V3, and left LOC, showed greater activity in response to distracter stimuli (both congruent and incongruent) in the 20% Inc block compared with the 60% Inc block, consistent with there being relatively greater proactive suppression in the latter. B, Average response to incongruent distracter stimuli (minus congruent) was extracted from the V3/V4 ROI and from the rMFG ROI, separately for the 20% Inc block and for the 60% Inc block. The increase in interference due to rarity of conflict was calculated within each ROI by subtracting values relative to the 60% Inc block from those relative to the 20% Inc block. The graph shows that subjects exhibiting increased interference in the visual ROI also exhibited an increase of activity in the rMFG.