Simulating a lesion in a basis function model of spatial representations: Comparison with hemineglect

The basis function theory of spatial representations explains how neurons i n the parietal cortex can perform nonlinear transformations from sensory to motor coordinates. The authors present computer Simulations showing that u nilateral parietal lesions leading to a neuronal gradient in basis function maps can account for the behavior of patients with hemineglect, including (a) neglect in line cancellation and line bisection experiments; (b) neglec t in multiple frames of reference simultaneously; (c) relative neglect, a f orm of what is sometime called object-centered neglect; and (d) neglect wit hout optic ataxia. Contralateral neglect arises in the model because the le sion produces an imbalance in the salience of stimuli that is modulated by the orientation of the body in space. These results strongly support the ba sis function theory for spatial representations in humans and provide a com putational model of hemineglect at the single-cell level.