Brain monitoring of erroneous actions performed by an avatar: An EEG study in immersive virtual reality

Controlling artificial virtual or physical agents is a fundamental challenge for both neuroscience and engineering. A crucial process for achieving optimal control is embodiment, i.e. the feeling that an artificial agent is part of our body (ownership) and we are responsible of its movement (agency). Here we recorded EEG in immersive virtual environment (Cave System) to investigate the role of embodiment on the activity of error monitoring brain systems during passive observation of actions errors made by an avatar seen in first person perspective (1pp) or third person perspective (3pp). Healthy participants (n = 10) observed an avatar performing a correct (70% of the trials) or an incorrect (30%) reach-to-grasp movement toward one of two mugs placed on a table. At the end of each trial, participants reported verbally how much they embodied the avatar’s arm (1 no embodiment, 5 maximal possible embodiment). High- and low-embodiment was reported respectively for 1pp (75.6%) and 3pp (24.5%) condition. Crucially, higher embodiment correlated with higher Medial-Frontal Theta Power and Error Related Negativity deflection in reaction to the erroneous grasping of an avatar seen in 1pp condition. No error-related differences in EEG signals were found in the 1pp correct and 3pp correct or erroneous trials. Thus, embodiment plays an important role for activating the error monitoring system in response to others' action errors. This result may be crucial for improving the flexibility of current brain computer interface devices.