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Abstract

[Introduction/Motivation:]

Body ownership and agency are both closely related to self-consciousness. While body ownership refers
to the experience of owning a body, agency refers to the attribution of an action to the Self and is further a
prerequisite for experiencing a sense of responsibility over the consequences of the action. In spite of
having been substantially studied, the neural underpinnings of agency are not yet clear. For example,
brain stimulation studies and computational models of agency suggest an involvement of sensorimotor
areas in the sense of agency [1], while behavioral experiments show that high levels of body ownership
over a surrogate (such as a virtual) body are already sufficient to induce illusory agency over its actions
[2,3]. We therefore aimed to investigate the role of sensorimotor areas in the feeling of agency and
responsibility.
[Methods:]

We used two different brain-computer interface (BCI) paradigms to control a virtual body, which were
based on the activation of either sensorimotor or visual areas. In the sensorimotor condition participants
moved a virtual arm using a BCI based on motor imagery and in the visual condition they moved the arm
using a BCI based on visual evoked potentials. We also compared agency and responsibility ratings to a
third observation condition, in which the virtual arm was passively moved.
[Results and Discussion:]

In both cases requiring sensorimotor or visual area activation, the intention to act and the results of the
action were the same. However, we found that agency was maximum and responsibility only occurred in
the motor imagery condition. Thus, these results show the critical role of sensorimotor areas in inducing
the sense of agency and responsibility. Our results thus provide evidence for the hypothesis that motor
activity contributes to forming the sense of agency and is essential for the sense of responsibility. This
further contributes to a better understanding of agency and responsibility in the context of BCI and how
the selection of BCI paradigms makes a difference on the self-attribution of actions.