Neural Representations of Self versus Other: Visual-Spatial Perspective Taking and Agency in a Virtual Ball-tossing Game

Abstract

Human self-consciousness relies on the ability to distinguish between oneself and others. We sought to explore the neural correlates involved in self-other representations by investigating two critical processes: perspective taking and agency. Although recent research has shed light on the neural processes underlying these phenomena, little is known about how they overlap or interact at the neural level. In a two-factorial functional magnetic resonance imaging (fMRI) experiment, participants played a ball-tossing game with two virtual characters ("avatars"). During an active/agency (ACT) task, subjects threw a ball to one of the avatars by pressing a button. During a passive/nonagency (PAS) task, they indicated which of the other avatars threw the ball. Both tasks were performed from a first-person perspective (1PP), in which subjects interacted from their own perspective, and a third-person perspective (3PP), in which subjects interacted from the perspective of an avatar with another location in space. fMRI analyses revealed overlapping activity in medial prefrontal regions associated with representations of one's own perspective and actions (1PP and ACT), and overlapping activity in temporal-occipital, premotor, and inferior frontal, as well as posterior parietal regions associated with representation of others' perspectives and actions (3PP and PAS). These findings provide evidence for distinct neural substrates underlying representations of the self and others and provide support for the idea that the medial prefrontal cortex crucially contributes to a neural basis of the self. The lack of a statistically significant interaction suggests that perspective taking and agency represent independent constituents of self-consciousness.

The timing of temporoparietal and frontal activations during mental own body transformations from different visuospatial perspectives

“…Other neuroimaging studies focused on the manipulation of the perspective during mental imagery and revealed activations within a network of brain areas including precuneus, prefrontal cortex, somatosensory cortex [Ruby and Decety, 2001], as well as right premotor cortex, superior temporal cortex, and cingulate cortex [David et al, 2006;Vogeley et al, 2004]. It is likely that subjects imagined changes in perspective and position jointly during most aforementioned studies, independently of whether investigators focused on body transformations or perspective changes.…”

Agency, gait and self-consciousness

“…Previous research on the perception of body postures (Reed et al, 2003) and biological motion (Cutting et al, 1988), as well as body-part agency , has observed a significant decrease in the performance of perceptual tasks for inverted stimuli (body postures or biological motion), the so-called inversion effect (1). Similarly, agency judgements and other performances decreased for stimuli rendered from a non-egocentred visuo-spatial perspective (David et al, 2006;Vogeley and Fink, 2003), e.g. a 180°rotation with respect to an arm movement (van den Bos and Jeannerod, 2002) (2).…”

Sense of agency and mentalizing: Dissociation of subdomains of social cognition in patients with schizophrenia

“…They showed a dissociation between impaired mentalizing but an intact sense of agency in autism. In addition, evidence from functional imaging studies also suggests neurobiological dissociation or independence: David et al (2006) for example reported that sense of agency and mentalizing, despite being assessed with the same stimulus material, showed no interaction at the neural level. In conclusion, it remains unclear whether these two processes represent two independent domains of social cognition or whether they can be conceptualized as interrelated processes.…”

“…Van Hooren et al (2008), in a factor analysis, found no overlap between these 11 processes among other social-cognitive processes. David et al (2006) investigated self-other distinction and mentalizing in a functional imaging study, but found no interaction of the two processes on a neural level. More readily comparable to our own study, David et al (2008) investigated sense of agency and mentalizing processes in HFA/AS.…”

“…That is, when the line drawn by the experimenter veered to one side (similar to our task), Nielsen's subjects adjusted their own line-drawing, suggesting they were not aware of the manipulation. Additionally, our task has been previously applied in combination with fMRI and TMS in healthy participants and in a patient group with HFA / AS, demonstrating the recruitment of brain areas relevant to the sense of agency, such as the IPL (David et al, 2006, David, et al, 2007. …”