The Contribution of Visual and Acoustic Information to Bodily Self Recognition

One of the most intriguing topic addressed by researchers across the cognitive sciences concerns the “self” and the self-other distinction. The present thesis adds to this debate by exploring the recognition of bodily self, based on visual and acoustical information. The first part of the present dissertation focuses on mechanisms and neural bases of bodily self, adopting a classical neuropsychological approach. Brain damaged patients were submitted to two different tasks designed for testing implicit and explicit self-body recognition using pictures depicting left and right hands as stimuli that belong to the participant or to other people. In Study 1, right and left brain damaged patients’ performance was compared to verify whether implicit and explicit self-body recognition are mediated by different cerebral networks that can be selectively impaired after focal brain lesion. A Voxel-based lesion-symptom mapping analysis revealed that an integrated cortical–subcortical right frontal (motor) network is crucial for an implicit knowledge of one’s own body. Conversely, both hemispheres contribute to an explicit knowledge of our body. In addition, Study 2 demonstrates how the implicit and explicit bodily knowledge is selectively impaired in patients with and without pathological embodiment of others’ body. The second part of the thesis explores the contribution of voice to self/other distinction. In Study 3, implicit and explicit self-voice recognition was investigated in healthy individuals. Interestingly, self-voice was better processed when an implicit rather than an explicit recognition was required. Finally, in Study 4, the anatomical basis of implicit and explicit self-voice recognition was investigated in neuropsychological patients. Behavioural and anatomical data demonstrates the involvement of right hemisphere in implicit processing and the joint contribution of both hemispheres in explicit recognition of self-voice. Overall, this thesis highlights the role played by visual and acoustic cues in building the sense of body-ownership.