Spatial Representation and Selection in the Brain: Neuropsychological and Computational Constraints

Abstract

We report joint neuropsychological and computational research into the nature of spatial representation and visual selection in the brain. In the first part of the paper, we discuss patterns of double dissociation between the performance of patients with selective brain lesions, suggesting the existence of independent forms of spatial representation in vision. In the second part we report the effects of simulating lesions in a computational model of translation-invariant object recognition. In the model, objects compete to achieve a mapping from retinal input to a translation-invariant “focus of attention”. Spatially selective lesions affect either the mapping from one side of retinal input or the mapping to one side of the attentional window, so generating different disorders of spatial representation and attention. We propose that forms of selection in vision, and different forms of spatial mapping, can emerge as a consequence of the need to achieve viewpoint-independent object recognition. Neuropsychological deficits typically attributed to disorders of visual attention or to particular spatial representations can arise out of damage to different parts of a visual system designed for object recognition.