Lesion in a basis function model of parietal cortex Comparison with hemineglect.pdf

To app ear in Parietal Lob e Contribution in Orientation in D Space Thier P and Karnath HO eds SpringerVerlag Lesion in a Basis Function Mo del of Parietal Cortex Comparison with Hemineglect A Pouget 1 and TJ Sejnowski 2 1 Institute for Cognitive and Computational Sciences Georgetown University Washington DC USA 2 Howard Hughes Medical Institute The Salk Institute for Biological Studies La Jolla CA USA and Department of Biology University of California San Diego La Jolla CA USA According to current theories of spatial representation the p ositions of ob jects are represen ted in multiple pro cessing systems throughout the brain each system sp ecialized for a particular sensorimotor transformation and using its own frame of reference Stein Goldb erg et al The lateral intra parietal area LIP for example app ears to enco de the lo cations of ob jects in o culo centric co ordinates presumably for the control of saccadic eye movements Colby et al The ventral intraparietal cortex VIP Colby and Duhamel and the premotor cortex Fogassi et al Graziano et al on the other hand seem to use headcentered co ordinates and might b e involved in the control of hand movements toward the face This mo dular theory of spatial representations is not fully consistent with the b ehavior of patients with parietal or frontal lesions Such lesions cause hemineglect a syndrome char