The Plastic Self: Investigating the Processes of Self-Face Recognition

This thesis investigates self-face recognition and the plasticity of
self-representations through several different behavioural and brain
stimulation manipulations. The experiments in Chapters 3 and 4 explore the
involvement of the temporoparietal area in self-other discrimination processes.
Using transcranial direct current stimulation (tDCS) to modulate neural
excitability in this region, the experiments in these chapters explore self-other
face discrimination and mental body rotation. Enhancing neural excitability
in this area appears to enhance familiar other-recognition and the ability to
take another's spatial perspective. Chapters 5 and 6 target brain areas
associated with multisensory bodily illusions with tDCS, and investigate their
involvement in self-updating. Chapter 5 explores the contribution of the
intraparietal sulcus to multisensory integration during the Enfacement
illusion. Chapter 6 investigates the effect of tDCS on somatosensory cortex
during a modified enfacement illusion paradigm to investigate self-updating.
Chapters 7 and 8 explore the novel use of a self-association paradigm to
update bodily and conceptual aspects of self. The experiments in these
chapters demonstrate that a previously unfamiliar face can be incorporated
into the conceptual self-representation. Chapter 7 investigates the existence of
a bidirectional modulatory link between conceptual and bodily aspects of self,
and found that changes to the conceptual self did not have an effect on the
bodily self-representation. The experiment in Chapter 8 investigates the
nature of the association created between the self-representation and the novel
face in Chapter 7 by testing whether the newly associated face affects
recognition of well-established perceptual and conceptual aspects of self.