| Summary: | The capacity for voluntary action lies at the heart of human nature. Healthy adults typically feel that they can exercise voluntary control over their actions, and thus change their physical and social environment. This feeling of autonomous control over one’s own action is a foundational concept for most human societies. However, neuromechanistic models of this ubiquitous experience remain unclear. This thesis explores the neural mechanisms underlying voluntary action control in the human brain and the experiences associated with it such as the experience of agency. After operationalizing voluntary action in a novel behavioural paradigm, we show that self-initiated actions are preceded by a specific preparatory process in the brain. Later experiments suggest that the experience of agency might be a metacognitive readout of this precursor process: a study of a patient with anarchic hand syndrome shows that precursor processes for voluntary action contribute to the sense of agency over outcomes of action. We then provide new causal evidence that the experiences of voluntary action could be influenced by modulating specific parts of the brain that may host these precursor processes such as parietal and frontal areas. Finally, we show that by pairing voluntary actions of one hand with involuntary movements of the other hand, key aspects of agency experience can transfer from voluntary to involuntary movements after repeated association. This later finding suggests that the experiences of voluntary action are not hardwired, but could be acquired through associative learning. This thesis concludes by proposing that a dedicated system in the human brain contributes to the preparation and execution of self-initiated voluntary actions and the characteristic subjective experiences associated with it.
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