| Cognitive control refers to a set of cognitive processes that "organize" and "oversee" the operation of more specialized cognitive processes. Most theories of cognitive control focus exclusively on the nature of the influence exerted by control processes, and lack an account of how the intervention of control processes is brought about. This is problematic, because it implies a sort of "homunculus" in the brain that "knows" when control is required. The objective of the proposed research program is to address this issue, using a combination of neuroimaging methods and computational modeling, by studying how control processes are recruited. The specific context in which we examine our research questions concerns the domain of speeded two-choice response tasks in which, depending on the particular stimulus, participants are required either to make an overt ("Go") response or to withhold ("NoGo") this response. Here, control is needed to resolve the competition between the execution and inhibition of a single response. Our hypothesis is that in this type of situation, control is recruited following the detection by anterior cingulate cortex of response conflicts in information processing. Upon the detection of such conflicts, the anterior cingulate cortex sends an "alarm signal" to other parts of the brain, including locus coeruleus and frontal cortex, that may help prevent future conflicts. We will develop new or extend existing neurocomputational models that help uncover the interaction between these alarm signals and the actual implementation of control. Detailed predictions of these models regarding behavior and brain activity will be tested in neuroimaging experiments, using EEG and/or fMRI. |
