
pmid: 17258693
The present study examines the functional and anatomical underpinnings of egocentric and allocentric coding of spatial coordinates. For this purpose, we set up a functional magnet resonance imaging experiment using verbal descriptions of spatial relations either with respect to the listener (egocentric) or without any body-centered relations (allocentric) to induce the two different spatial coding strategies. We aimed to identify and distinguish the neuroanatomical correlates of egocentric and allocentric spatial coding without any possible influences by visual stimulation. Results from sixteen participants show a general involvement of a bilateral fronto-parietal network associated with spatial information processing. Furthermore, the egocentric and allocentric conditions gave rise to activations in primary visual areas in both hemispheres. Moreover, data show separate neural circuits mediating different spatial coding strategies. While egocentric spatial coding mainly recruits the precuneus, allocentric coding of space activates a network comprising the right superior and inferior parietal lobe and the ventrolateral occipito-temporal cortex bilaterally. Furthermore, bilateral hippocampal involvement was observed during allocentric, but not during egocentric spatial processing. Our results demonstrate that the processing of egocentric spatial relations is mediated by medial superior-posterior areas, whereas allocentric spatial coding requires an additional involvement of right parietal cortex, the ventral visual stream and the hippocampal formation. These data suggest that a hierarchically organized processing system exists in which the egocentric spatial coding requires only a subsystem of the processing resources of the allocentric condition.
Adult, Male, Brain Mapping, Adult; Brain Mapping; Female; Functional Laterality; Humans; Image Processing, Computer-Assisted; Judgment; Magnetic Resonance Imaging/methods; Male; Oxygen/blood; Parietal Lobe/blood supply; Parietal Lobe/physiology; Photic Stimulation/methods; Space Perception/physiology, Magnetic Resonance Imaging, Functional Laterality, Oxygen, Judgment, Parietal Lobe, Space Perception, Image Processing, Computer-Assisted, Humans, Female, Photic Stimulation
Adult, Male, Brain Mapping, Adult; Brain Mapping; Female; Functional Laterality; Humans; Image Processing, Computer-Assisted; Judgment; Magnetic Resonance Imaging/methods; Male; Oxygen/blood; Parietal Lobe/blood supply; Parietal Lobe/physiology; Photic Stimulation/methods; Space Perception/physiology, Magnetic Resonance Imaging, Functional Laterality, Oxygen, Judgment, Parietal Lobe, Space Perception, Image Processing, Computer-Assisted, Humans, Female, Photic Stimulation
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 239 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 1% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
