Action conflict under control: An integrated perspective on action control and its underlying neurophysiological and computational mechanisms

Performing a goal-directed action requires one to perceive the environment and act upon changes within this environment. For instance, when playing soccer one might be faked out by an opponent (e.g., Robben). In such a case one needs to overcome the perceived impulse of following the direction of the leg of the opponent and instead act on the direction of the ball. In this example, the goal-directed action entails resisting the impulse to react to the distracting fake maneuver and instead reacting to the movement of the ball. Several theoretical frameworks have been proposed over the last five decades to understand how the brain handles situations with conflicting actions opportunities. More recently, brain-behavior relationships have been investigated to differentiate among these different theoretical frameworks. However, thus far, evidence comes mainly from correlational research using techniques like Electroencephalography (EEG) or functional Magnetic Resonance Imaging (fMRI). Therefore it is still an open question how interference from action conflict is resolved and by which physiological mechanism(s).
In this thesis, psychological concepts of action control are re-examined using a neurophysiological technique that allows causal inferences about brain function, namely Transcranial Magnetic Stimulation (TMS), and a computational modeling approach. With TMS we can measure the physiological state of the motor cortex during conflict situations, identify which brain regions are causally involved and how key nodes of those brain regions interact with each other. Finally, the results from these approaches are discussed in the context of the different existing theoretical frameworks.