The Interaction of Spatial Reference Frames and Hierarchical Object Representations: A Computational Investigation of Drawing in Hemispatial Neglect

In drawing a figure, hemispatial neglect patients typically produce an adequate representation of parts on the right of the figure while omitting significant features on the left. This contralateral neglect is influenced by multiple spatial reference frames and by the hierarchical structure of the object(s) in the figure. The current work presents a computational characterization of the interaction among these influences to account for the way in which neglect manifests in drawing. Neglect is simulated by a “lesion” (monotonic drop-off from right to left) that can affect performance in both object-centered and viewer-centered reference frames. The joint effects of neglect in both these frames provide a coherent account of the drawing performance of a patient, JM, and may be extended to account for the copying performance of other patients across a range of objects and scenes.