Neuronal activity in macaque SEF and ACC during performance of tasks involving conflict

It has been suggested on the basis of previous studies involving functional MRI ( fMRI) and single-neuron recording that neurons of the supplementary eye field (SEF) and anterior cingulate cortex (ACC) monitor conflict. To test this idea, we carried out microelectrode recording in monkeys performing a color-conditional eye movement task in which red and green cues instructed leftward and rightward saccades, respectively. In a variant inducing conflict by spatial incompatibility, the cue was presented either at the location of the target ( no conflict) or opposite the location of the target ( conflict). In a variant inducing conflict by reversal, the foveal cue either remained one color ( no conflict) or reversed color after 100 ms ( conflict), with the monkey required to follow the instruction conveyed by the second color. In both tasks, conflict was evident in behavioral measures ( reduced percent correct and slowed reaction time) and in physiological measures ( reduced strength of directional activity among direction-selective neurons). In the SEF, there was a tendency for neurons to fire more strongly on trials involving conflict, but this effect took the form of modulation of task-related activity among direction-selective neurons, not of a pure conflict-monitoring signal. In the ACC, there was no conflict-related enhancement. These results are incompatible with the idea that the SEF and ACC contain populations of neurons specialized for monitoring conflict.