Different cortical activations for subjects using allocentric or egocentric strategies in a virtual navigation task

Abstract

Subjects were required to navigate through a virtual 3D labyrinth presented on a screen while fMRI images were obtained. Contrasting the fMRI images obtained during the navigation trials with appropriate control conditions revealed a bilateral network comprising the parietal lobe (including the intraparietal sulcus) and various lateral and medial premotor areas. The subjects using an allocentric strategy showed stronger activation in the medial temporal areas including the parahippocampal region, the hippocampus, and the thalamus. In addition, the cerebellum was also active in those subjects. We believe that this activation pattern is related to visually guided memory retrieval based on generalized spatial maps. The stronger activation in the thalamic-basal ganglia-cerebellar-loop points to a more automatic support of memory and attentional processes possibly supporting memorization of spatial maps.

Egocentric and object-based transformations in the laterality judgement of human and animal faces and of non-corporeal objects

“…Galati et al [20], for example, demonstrated that in a visuospatial judgement task (line bisection) both strategies activate a fronto-parietal circuit, but that the object-based (labelled "allocentric" in the paper) strategy differed in that it had smaller activations throughout the circuit and additionally recruited subcortical regions related to spatial memory (hippocampal and parahippocampal). Similar findings have been reported with virtual reality navigation tasks [27], where the object-based ("allocentric") strategy additionally recruited the thalamus and cerebellum. Moreover, an object-based strategy is not completely independent from posture variations, suggesting that smaller motor activations are always needed to operate with body parts mental images [40].…”

Playing Super Mario induces structural brain plasticity: gray matter changes resulting from training with a commercial video game

“…12,31,32 In a functional neuroimaging study, participants using an allocentric strategy showed stronger activation in parahippocampal regions, the hippocampus, thalamus and the cerebellum. 13,14,33 It has been assumed that initially egocentric imagery decays rapidly as more stable allocentric representations are encoded. 34 Older adults overwhelmingly prefer an egocentric strategy, while younger adults are equally distributed between egocentric and allocentric preferences.…”

Mental Imagery for Full and Upper Human Bodies: Common Right Hemisphere Activations and Distinct Extrastriate Activations

“…In an egocentric frames the spatial coordinates of an object are encoded with respect to the observer's body. While, in an allocentric frames the spatial coordinates of an object are represented on the base of external objects (Kosslyn 1994;Galati et al 2000;Vogeley and Fink 2003;Jordan et al 2004;Zaehle et al 2007). Classically the OBT-task is performed using an egocentric frame of reference, while the LAT-task is a control task not asking for a transformation with respect to either the egocentric nor the allocentric frame of reference.…”