Poster F8, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Towards a unified model of spatial neglect and its anatomical constituents
Radek Ptak1,2,3, Armin Schnider1,2, Elena Pedrazzini1; 1Medical school, Geneva University, Switzerland, 2Division of neurorehabilitation, University Hospitals Geneva, Switzerland, 3Faculty of psychology and educational sciences, Geneva University, Switzerland
Distinct cognitive processes are thought to underlie the heterogeneous nature of spatial neglect. Here we explore two hypothetical processes that are held responsible for the occurrence of deficits in distinct cognitive tasks: object-centered and space-based processing. Previous studies have observed that a bias favoring object-centered processing (such as in copying, reading or line bisection) results from damage to posterior inferior regions while spatial exploration reflects damage to more dorsal and anterior regions. Based on these findings, we tested a theoretical model of neglect that takes in account the underlying types of processing and relates them to neuroanatomical predictors. 101 right-hemisphere damaged patients were examined with classic neuropsychological tests and participated in a structural MRI scanning session. Lesions were reconstructed and transferred into template space, and the percentage of damaged voxels within 4 regions of interest (ROIs: temporal-parietal junction, frontal eye field, middle frontal gyrus and intraparietal sulcus) was calculated. The relation between damage in the four ROIs with neglect measures was examined with a structural equation model by assuming two latent variables: object-centered processing (involved in line bisection and word errors in reading) and space-based processing (involved in cancellation tasks). The model was a significant predictor of the relations between variables. Damage to the intraparietal sulcus predicted object-centered, but not space-based processing, while damage to the temporal-parietal junction predicted space-based, but not object-centered processing. These data show that neglect reflects distinct object-centered and space-based deficits which result from superior parietal and inferior parietal damage, respectively.
Topic Area: ATTENTION: Spatial