From Part- to Whole-Body Ownership in the Multisensory Brain

Abstract

The question of how we experience ownership of an entire body distinct from the external world is a fundamental problem in psychology and neuroscience [1-6]. Earlier studies suggest that integration of visual, tactile, and proprioceptive information in multisensory areas [7-11] mediates self-attribution of single limbs. However, it is still unknown how ownership of individual body parts translates into the unitary experience of owning a whole body. Here, we used a "body-swap" illusion [12], in which people experienced an artificial body to be their own, in combination with functional magnetic resonance imaging to reveal a coupling between the experience of full-body ownership and neural responses in bilateral ventral premotor and left intraparietal cortices, and left putamen. Importantly, activity in the ventral premotor cortex reflected the construction of ownership of a whole body from the parts, because it was stronger when the stimulated body part was attached to a body, was present irrespective of whether the illusion was triggered by stimulation of the hand or the abdomen, and displayed multivoxel patterns carrying information about full-body ownership. These findings suggest that the unitary experience of owning an entire body is produced by neuronal populations that integrate multisensory information across body segments.

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

“…Both studies by Ionta et al (2011) and Petkova et al (2011) elaborated on the paradigm used to induce illusory ownership of an artificial hand, known as the rubber hand illusion (RHI, Botvinick & Cohen, 1998). The RHI consists in feeling a tactile stimulus on one's own (unseen) hand and concurrently viewing a rubber hand being synchronously touched.…”

“…The studies by Ionta et al (2011) and Petkova et al (2011) are fMRI adaptations of the ''full-body illusion'' and the ''body swap illusion'' respectively. But, although they share a similar experimental approach-using multisensory stimulation to understand the neural bases of bodily self-consciousness-their results differ in terms of behavioural, phenomenological and neural outcomes.…”

“…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).…”

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

“…In the rubber hand illusion (RHI), the visuo-tactile congruent stimulation of one's own hidden hand and a visible anatomical compatible fake hand induces the sensation that the prosthetic limb belongs to oneself [4,11]. Similarly, the full body illusion (FBI) can be induced; thus, congruent visuo-tactile stimulation at the trunk can induce self-identification and self-location changes with respect to a virtual or fake body [12,13,9,14].…”