| dc.description.abstract | In our interactions with the world, we are constantly monitoring the state of our environment and using this information to guide decisions about our actions. Successful decision-making relies on effective cognitive control – a set of processes that allow for the flexible allocation of cognitive resources to promote effective behavior. Cognitive control is vital when there are multiple competing demands or when we have automatic or learned actions that may interfere with our goal. Stopping these inappropriate actions before their execution is achieved through response inhibition. Successful response inhibition not only requires the recruitment of control processes in reaction to a salient event but also involves monitoring and adjusting actions in line with the demands of the environment. The medial frontal cortex is an important region for this process, but activity within this area is complex and signals vary markedly with no apparent pattern or adherence to a single cognitive theory or computational model. This dissertation combined neurophysiological methods across temporal and spatial scales with established cognitive models to understand how the medial frontal cortex contributes to cognitive control. In chapters 3 and 4, we observed that signals in the supplementary eye field and recorded over the medial frontal cortex lack the dynamics required to contribute to reactive inhibition. In chapters 5 and 6, we discovered activity in the medial frontal cortex that reflected action monitoring processes and other aspects of cognitive control. In the supplementary eye field, we defined novel patterns of activity that represent a task goal and contribute to the evaluation of temporal features of the environment. In the midcingulate cortex, we describe novel patterns of activity that proactively differentiate between whether a movement will be made or not. Secondary to these findings, work in chapters 4 and 5 highlighted interesting distinctions in the relationship between intracortical and EEG signals. Spiking in upper cortical layers reflected the magnitude of the event-related potentials recorded over the scalp, but burst activity in the local field potential did not correspond with burst activity in the EEG. The findings presented in this dissertation have advanced our understanding of how cognitive control is represented in the medial frontal cortex, challenging current theories of stopping in humans and providing new ideas and directions for consideration through future research. | |
