Widespread temporal coding of cognitive control in human prefrontal cortex

When making decisions we often face the need to adjudicate between conflicting strategies or courses of action. Our ability to understand the neuronal processes underlying conflict processing is limited on the one hand by the spatiotemporal resolution of fMRI and, on the other, by imperfect cross-species homologies in animal model systems. Here we examine responses of single neurons and local field potentials in human neurosurgical patients in two prefrontal regions critical to controlled decision-making, dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (dlPFC). While we observe typical modest conflict related firing rate effects, we find a widespread effect of conflict on spike-phase coupling in dACC and on driving spike-field coherence in dlPFC. These results support the hypothesis that a cross-areal rhythmic neuronal coordination is intrinsic to cognitive control in response to conflict, and provide new evidence to support the hypothesis that conflict processing involves modulation of dlPFC by dACC.