Abstract
The simple act of reaching for a cup of coffee is closely monitored by multiple error evaluation and learning systems within the brain. The reason we need multiple error systems to evaluate our movements is simple – different neural systems are tasked with evaluating different types of errors. High-level errors, errors indicating the failure to achieve system goals, appear to be evaluated within the medial-frontal cortex. Low-level errors, errors brought about by environmental changes and/or errors in a motor command, appear to be resolved within an ongoing movement by error processing systems within the posterior parietal cortex and the cerebellum. Here, we conducted a series of studies using event-related brain potentials (ERP) to examine error evaluation during the execution of goal-directed aiming movements. Our results demonstrate that high-level errors elicit the error-related negativity – an ERP component associated with error evaluation by a reinforcement learning system within the medial-frontal cortex. Low-level errors elicited larger N100 responses – an ERP component typically associated with early visual processing and the focusing of visuospatial attention. Additionally, low-level errors also modulated the amplitude of the P300, an ERP component that has historically been associated with the updating of an internal model of the task environment. Together, our results provide further support for the hierarchical error-processing hypothesis – a hypothesis that posits that the multiple error evaluation systems within the brain are hierarchically organized to provide an overall system that is responsible for both motor control and motor learning.
