Neural Correlates of the Embodied Sense of Agency

Abstract

The Sense of Agency (SoA) is the subjective experience that I am in control of my actions. Recent accounts have distinguished two levels in the formation of SoA - early implicit sensorimotor processes (feeling of agency) and later explicit higher-level processes, incorporating ones thoughts and beliefs (judgment of agency). Even though SoA is fundamental to our interactions with the external world and the construct of the self, its underlying neural mechanism remains elusive. In the current pre-registered electroencephalography (EEG) study, we used time-frequency analysis and Multivariate Pattern Analysis (MVPA) to investigate the electrophysiological characteristics associated with SoA. We used an established embodied virtual reality paradigm in which visual feedback of a movement is modulated to examine the effect of conflicts between the predicted and perceived sensory feedback. Participants moved their finger and were shown a virtual hand that either mimicked their movement or differed anatomically (different finger) or spatially (angular shift), then judged their SoA over the observed movement while their brain activity was recorded. In accordance with our pre-registered hypothesis, we found that a reduction of SoA is associated with decreased attenuation in the alpha frequency band. Increased power in the theta frequency band was also associated with SoA reduction. Importantly, we show that trials containing a sensorimotor alteration vs. trials containing no alteration can reliably be decoded with up to 68% accuracy starting around 200ms after the movement onset. Finally, cross-decoding analyses revealed similar neural patterns for reduced SoA in the anatomical and spatial conditions, starting around 500ms after the movement onset. Together, our results reveal a cortical signature of loss of SoA and provide neural evidence supporting the hypothesis of a two-level formation of SoA - an early domain-specific component, possibly the equivalent of the implicit feeling of agency, and a late domain-general component, possibly the equivalent of the explicit judgment of agency.