Human EEG Correlates of Spatial Navigation within Egocentric and Allocentric Reference Frames

We investigated the impact of path complexity on brain dynamics of subjects who preferentially use an egocentric (Turners) or an allocentric (Nonturners) reference frame during spatial navigation. Participants indicated a return bearing direction (‘point-to-origin’) following visual presentation of virtual tunnel passages, varying with respect to the complexity of the outbound path. High-density electroencephalographic activity was recorded continuously and spatially filtered with Independent Component Analysis. For Turners, rotations and translations were associated with decreased and increased (8-12 Hz) alpha activity in occipito-parietal cortex, whereas Nonturners displayed increased alpha within cortical areas along the ventral pathway, as well as in retrosplenial cortex, an area supporting bidirectional exchange of information between parietal and medial temporal regions. Both groups displayed complexity-related modulations of frontal midline (4-8 Hz) theta activity. Findings extend results of hemodynamic imaging and neuropsychological studies on spatial navigation and emphasize the need for considering individual proclivities when investigating human navigation performance.