# Predicting the bodily self in space and time

## TL;DR

The study explores how the brain uses motor predictions to distinguish the self from the environment, using virtual reality setups to test self-location and body perception.

## Contribution

A novel full-body illusion paradigm with varying levels of motion control was developed to investigate self-perception and agency in virtual environments.

## Key findings

- Healthy adults could align with a third-person avatar without losing self-location or identity.
- Motor predictions help distinguish self from others and maintain a stable sense of self.
- The study suggests potential applications in neurorehabilitation and treating disorders like psychosis.

## Abstract

To understand how the human brain distinguishes itself from external stimulation, it was examined if motor predictions enable healthy adult volunteers to infer self-location and to distinguish their body from the environment (and other agents). By uniquely combining a VR-setup with full-body motion capture, a full-body illusion paradigm (FBI) was developed with different levels of motion control: (A) a standard, passive FBI in which they had no motion control; (B) an active FBI in which they made simple, voluntary movements; and (C) an immersive game in which they real-time controlled a human-sized avatar in third person. Systematic comparisons between measures revealed a causal relationship between (i) motion control (prospective agency), (ii) self-other identification, and (iii) the ability to locate oneself. Healthy adults could recognise their movements in a third-person avatar and psychologically align with it (action observation); but did not lose a sense of place (self-location), time (temporal binding), nor who they are (self/other). Instead, motor predictions enabled them to localise their body and to distinguish self from other. In the future, embodied games could target and strengthen the brain’s control networks in psychosis and neurodegeneration; real-time motion simulations could help advance neurorehabilitation techniques by fine-tuning and personalising therapeutic settings.