The Neural Bases of Egocentric Spatial Representation for Extracorporeal and Corporeal Tasks: An fMRI Study

Abstract

(1) Background: Humans use reference frames to elaborate the spatial representations needed for all space-oriented behaviors such as postural control, walking, or grasping. We investigated the neural bases of two egocentric tasks: the extracorporeal subjective straight-ahead task (SSA) and the corporeal subjective longitudinal body plane task (SLB) in healthy participants using functional magnetic resonance imaging (fMRI). This work was an ancillary part of a study involving stroke patients. (2) Methods: Seventeen healthy participants underwent a 3T fMRI examination. During the SSA, participants had to divide the extracorporeal space into two equal parts. During the SLB, they had to divide their body along the midsagittal plane. (3) Results: Both tasks elicited a parieto-occipital network encompassing the superior and inferior parietal lobules and lateral occipital cortex, with a right hemispheric dominance. Additionally, the SLB > SSA contrast revealed activations of the left angular and premotor cortices. These areas, involved in attention and motor imagery suggest a greater complexity of corporeal processes engaging body representation. (4) Conclusions: This was the first fMRI study to explore the SLB-related activity and its complementarity with the SSA. Our results pave the way for the exploration of spatial cognitive impairment in patients.

Spatial perspective and identity in visual awareness of the bodily self-other distinction

“…Among the various pattern of brain activations, the work reported that a specific brain structure (i.e., the left Superior Parietal Lobule SPL) was significantly more activated in first-, than in third-, person perspective. Interestingly, other studies investigating the neural correlates of representing the environment from egocentric perspectives in a broader sense reported the same selective activation 53 – 55 . Such set of evidence seems to be in line with the known role of the SPL in representing nearby stimuli in body-centered coordinates 56 .…”

Role of the right middle occipital gyrus in egocentric spatial orientation in reference to gravitational information: Evidence from a pre-registered rTMS study

“…The MOG, as part of the lateral occipital complex, is a higher-order visual cortical region that processes spatial information about a viewed object, such as shape (Cant et al, 2009), location (Liu et al, 2017; Galati et al, 2001; Saj et al, 2014; Chen et al, 2012; Reiner et al, 2010), and orientation (Leplaideur et al, 2021; Saj et al, 2019). A recent meta-analysis (Derbie et al, 2021) showed that the rMOG is activated when a task requires visuospatial processing of information about an object in reference to the participants’ own body (egocentric spatial coding), rather than to other objects (allocentric spatial coding).…”

Editorial: Advances in Understanding and Rehabilitating Unilateral Spatial Neglect

“…Stephanie Leplaideur et al [3] explored the neural bases of egocentric spatial representation in healthy participants using fMRI. Comparing two tasks testing the extracorporeal and corporeal spatial representation of body in space, they revealed the presence of parieto-occipital networks, with a right-hemispheric dominance, associated with both extracorporeal and corporeal tasks.…”