Multisensory Mechanisms in Temporo-Parietal Cortex Support Self-Location and First-Person Perspective

Abstract

Self-consciousness has mostly been approached by philosophical enquiry and not by empirical neuroscientific study, leading to an overabundance of diverging theories and an absence of data-driven theories. Using robotic technology, we achieved specific bodily conflicts and induced predictable changes in a fundamental aspect of self-consciousness by altering where healthy subjects experienced themselves to be (self-location). Functional magnetic resonance imaging revealed that temporo-parietal junction (TPJ) activity reflected experimental changes in self-location that also depended on the first-person perspective due to visuo-tactile and visuo-vestibular conflicts. Moreover, in a large lesion analysis study of neurological patients with a well-defined state of abnormal self-location, brain damage was also localized at TPJ, providing causal evidence that TPJ encodes self-location. Our findings reveal that multisensory integration at the TPJ reflects one of the most fundamental subjective feelings of humans: the feeling of being an entity localized at a position in space and perceiving the world from this position and perspective.

Illusory self-identification with an avatar reduces arousal responses to painful stimuli

“…Here, we sought for a similar modulation of pain responses induced by the vision of a virtual body that also depended upon the level of illusory self-identification with that body during a full-body illusion [9] induced by controlled robotic stimulations [23][24][25].…”

“…In two experiments, we combined robotic stimulation and virtual reality technology in order to induce the FBI [23][24][25]. We then investigated the response to acute noxious stimuli delivered to the participant's hand, through the recording of the SCR, corresponding to the activation of the autonomic nervous system (ANS) [26][27][28].…”

Bodily ownership and self-location: Components of bodily self-consciousness

“…These studies exemplify the first two assumptions noted above: each of these studies had the explicit aim of combining multisensory stimulation, concurrently delivered to the participant's body and to a virtual body, with fMRI to study the neural mechanisms underlying global forms of bodily self-consciousness. And in both studies, the manipulation of these forms of bodily self-consciousness was thought to be demonstrated by both explicit reports and measurement of behavioural effects: a shift in the perceived self-location towards the location of the virtual body in Ionta et al's (2011) study, and by an increase in autonomic response to a threat towards the virtual body in Petkova et al's (2011) study. But more interesting for our purposes is the fact that whilst similar multisensory stimulation was used, the results of these two studies differed both with respect to the phenomenological effects inferred from participants' reports and behavioural measures, and the neural correlates of these effects.…”

“…Our evaluation of this assumption will initially focus on two studies: one by Ionta et al (2011) and the other by Petkova et al (2011). These studies exemplify the first two assumptions noted above: each of these studies had the explicit aim of combining multisensory stimulation, concurrently delivered to the participant's body and to a virtual body, with fMRI to study the neural mechanisms underlying global forms of bodily self-consciousness.…”

“…But more interesting for our purposes is the fact that whilst similar multisensory stimulation was used, the results of these two studies differed both with respect to the phenomenological effects inferred from participants' reports and behavioural measures, and the neural correlates of these effects. In particular, distinct changes in bodily self-consciousness were related to neural activity in either the temporo-parietal junction (TPJ) in Ionta et al (2011), or in the ventral premotor cortex (vPMc) in Petkova et al (2011).…”