Agency in Walking Humans Sensorimotor & [and] Cognitive Contributions to Bodily Self-Consciousness

Acting in our environment and experiencing ourselves as conscious agents are fundamental aspects of human selfhood. While large advances have been made with respect to understanding human sensorimotor control from an engineering approach, knowledge about its interaction with cognition and the conscious experience of movement, i.e. the sense of agency, is still speculative. In this thesis I have investigated these relationships by implementing a Virtual Reality platform, which allowed me to adapt agency paradigms previously limited to movements of individual body-parts to continuous full-body movements, i.e. locomotion. In a series of behavioural studies I investigated how a) spatial and b) temporal sensorimotor mismatches between participants' veridical gait-movements and their life-size visual feedback affected agency and gait. Our results illustrate that humans monitor the details of their movements and their location in space with surprisingly low accuracy. Participants did not become aware of sensorimotor mismatches below 15° and temporal mismatches of 210 ms, even though they automatically adapted their movements. These data confirm that gait and gait agency are distinct brain processes, that these can further be separated by taxing cognitive resources in dual task paradigms, and that they are comparable to agency mechanisms that have been described for upper limb movements. Together, these studies help to investigate sensorimotor components of selfhood that are of scientific, clinical, and legal relevance.


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