The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of (...) activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed. (shrink)

One hypothesis concerning the human dorsal anterior cingulate cortex (ACC) is that it functions, in part, to signal the occurrence of conflicts in information processing, thereby triggering compensatory adjustments in cognitive control. Since this idea was first proposed, a great deal of relevant empirical evidence has accrued. This evidence has largely corroborated the conflict-monitoring hypothesis, and some very recent work has provided striking new support for the theory. At the same time, other findings have posed specific challenges, especially concerning the (...) way the theory addresses the processing of errors. Recent research has also begun to shed light on the larger function of the ACC, suggesting some new possibilities concerning how conflict monitoring might fit into the cingulate's overall role in cognition and action. (shrink)

The accessibility of suppressed thoughts was compared with the accessibility of thoughts on which Ss were consciously trying to concentrate. In Experiment I, Ss made associations to word prompts as they tried to suppress thinking about a target word (e.g., house) or tried to concentrate on that word. Under the cognitive load imposed by time pressure, they gave the target word in response to target-related prompts (e.g., home) more often during suppression than during concentration. In Experiment 2, reaction times for (...) naming colors of words were found to be greater under conditions of cognitive load when Ss were asked to suppress thinking of the word than under conditions of no cognitive load or when Ss were asked to concentrate on the word. The results support the idea that an automatic search for the suppression target increases the accessibility of the target during.. (shrink)