DOI 10.1007/s00221-008-1482-xRESEARCH ARTICLE Electroencephalographic correlates of target and outcome errors

Abstract DiVerent neural systems underlie the evaluation of diVerent types of errors. Recent electroencephalographic evidence suggests that outcome errors—errors indicating the failure to achieve a movement goal—are evaluated within medial-frontal cortex (Krigolson and Holroyd 2006, 2007a, b). Conversely, evidence from a variety of manual aiming studies has demonstrated that target errors—dis-crepancies between the actual and desired motor command brought about by an unexpected change in the movement environment—are mediated within posterior parietal cortex (e.g., Desmurget et al. 1999, 2001; Diedrichsen et al. 2005). Here, event-related brain potentials (ERP) were recorded to assess medial-frontal and parietal ERP components associ-ated with the evaluation of outcome and target errors during performance of a manual aiming task. In line with previous results (Krigolson and Holroyd 2007a), we found that target perturbations elicited an ERP component with a parietal scalp distribution, the P300. However, the timing of kine-matic changes associated with accommodation of the target perturbations relative to the timing of the P300 suggests that the P300 component was not related to the online con-trol of movement. Instead, we believe that the P300 evoked by target perturbations reXects the updating of an internal model of the movement environment. Our results also revealed that an error-related negativity, an ERP compo-nent typically associated with the evaluation of speeded response errors and error feedback, was elicited when par-ticipants missed the movement target. Importantly, this result suggests that a reinforcement learning system within medial-frontal cortex may play a role in improving subse-quent motor output