Where is a nose with respect to a foot? The left posterior parietal cortex processes spatial relationships among body parts.
Neuropsychological studies suggest that patients with left parietal lesions may show impaired localization of parts of either their own or the examiner's body, despite preserved ability to identify isolated body parts. This deficit, called autotopagnosia, may result from damage to the Body Structural Description (BSD), a representation which codes spatial relationships among body parts. We used functional magnetic resonance imaging to identify the neural mechanisms underlying the BSD. Two human body or building parts (factor: STIMULI) were shown to participants who either identified them or evaluated their distance (factor: TASK). The analysis of the interaction between STIMULI and TASK, which isolates the neural mechanism underlying BSD, revealed an activation of left posterior intraparietal sulcus (IPS) when the distance between body parts was evaluated. The results show that the left IPS processes specifically the information about spatial relationships among body parts and thereby suggest that damage to this area may underlie autotopagnosia.
Corradi-Dell'Acqua
Corrado
C
Cognitive Neuroscience Sector, Scuola Internazionale Superiore di Studi Avanzati (SISSA-ISAS), 34014 Trieste, Italy. corradi@sissa.it
Hesse
Maike D
MD
Rumiati
Raffaella I
RI
Fink
Gereon R
GR
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D005528:Foot / Q000033:anatomy & histology*; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009666:Nose / Q000033:anatomy & histology*; D010296:Parietal Lobe / Q000502:physiology*; D010781:Photography; D011187:Posture; D013003:Somatosensory Cortex / Q000502:physiology*; D013028:Space Perception; D055815:Young Adult