The role of the pain-evoked negative difference potential in dual-task response conflict

The possible role of the generators of the sural nerve pain-evoked negative difference potential (NDP), the anterior cingulate cortex and supplementary somatosensory area, in monitoring response conflict was investigated in 19 healthy adults. Each trial consisted of a visual arrow stimulus and a painful electrical stimulus applied to the sural nerve. The subjects determined whether their left or right sural nerve had been stimulated and whether the arrow was pointing to the left or to the right. The sural nerve pain detection task reaction times and response errors were greater in the incongruent condition, where the arrow pointed to the side opposite of that receiving the sural nerve pain, than in the congruent condition, where the arrow pointed to the same side as that receiving the sural nerve pain. Response conflict was greatest, therefore, in the incongruent condition. There were no differences in NDP amplitude across the congruent and incongruent conditions. These results argue against the hypothesis that the NDP generators are involved in monitoring response conflict.