Are All Spatial Reference Frames Egocentric? Reinterpreting Evidence for Allocentric, Object-Centered, or World-Centered Reference Frames.

Flavia Filimon

doi:10.3389/fnhum.2015.00648

Abstract

The use and neural representation of egocentric spatial reference frames is well-documented. In contrast, whether the brain represents spatial relationships between objects in allocentric, object-centered, or world-centered coordinates is debated. Here, I review behavioral, neuropsychological, neurophysiological (neuronal recording), and neuroimaging evidence for and against allocentric, object-centered, or world-centered spatial reference frames. Based on theoretical considerations, simulations, and empirical findings from spatial navigation, spatial judgments, and goal-directed movements, I suggest that all spatial representations may in fact be dependent on egocentric reference frames.

Highlights

Do animals use spatial reference frames that are independent of an egocentric viewpoint? In other words, does the brain represent map-like spatial layouts, or spatial locations of objects and landmarks, in an allocentric, or “other-centered” spatial reference frame, independent of the ego’s perspective or location? Does the choice of spatial reference frame depend on perception vs. sensorimotor interactions with the environment, such as target-directed movements or navigation?It is well-established that neurons in many brain regions, especially parieto-frontal cortex, represent the spatial location of objects in egocentric spatial reference frames, centered on various body parts such as the eye, the head, or the hand (Colby, 1998; Hagler et al, 2007; Sereno and Huang, 2014)
Based on theoretical considerations and empirical evidence, I suggest that object-centered, allocentric, or world-centered spatial representations may be explained via egocentric spatial
The evidence reviewed here, spanning behavioral, neuronal, neuropsychological, and neuroimaging studies, suggests that allocentric spatial representations may not be independent of egocentric coordinates, whether for navigation, spatial perception, or target-directed movements

Summary

INTRODUCTION

Do animals use spatial reference frames that are independent of an egocentric viewpoint? In other words, does the brain represent map-like spatial layouts, or spatial locations of objects and landmarks, in an allocentric, or “other-centered” spatial reference frame, independent of the ego’s perspective or location? Does the choice of spatial reference frame depend on (passive) perception vs. sensorimotor interactions with the environment, such as target-directed movements or navigation?. Whether the brain represents spatial locations of external objects relative to other objects in an allocentric or object-centered spatial reference frame, or constructs an abstract map of such relationships that is independent of the egocentric perspective, is debated (Bennett, 1996; Driver and Pouget, 2000; Wang and Spelke, 2002; Burgess, 2006; Wehner et al, 2006; Rorden et al, 2012; Li et al, 2014). Based on theoretical considerations and empirical evidence, I suggest that object-centered, allocentric, or world-centered spatial representations may be explained via egocentric spatial

Do Allocentric Spatial Representations Exist?

CONCLUSIONS AND PREDICTIONS