SPATIAL REPRESENTATION AND SELECTION IN THE BRAIN - NEUROPSYCHOLOGICAL AND COMPUTATIONAL CONSTRAINTS

We report joint neuropsychological and computational research into the nature of spatial representation and visual selection in the brain. I n the first part of the paper, we discuss patterns of double dissociat ion between the performance of patients with selective brain lesions, suggesting the existence of independent forms of spatial representatio n in vision. In the second part we report the effects of simulating le sions in a computational model of translation-invariant object recogni tion. In the model, objects compete to achieve a mapping from retinal input to a translation-invariant ''focus of attention''. Spatially sel ective lesions affect either the mapping from one side of retinal inpu t or the mapping to one side of the attentional window, so generating different disorders of spatial representation and attention. We propos e that forms of selection in vision, and different forms of spatial ma pping, can emerge as a consequence of the need to achieve viewpoint-in dependent object recognition. Neuropsychological deficits typically at tributed to disorders of visual attention or to particular spatial rep resentations can arise out of damage to different parts of a visual sy stem designed for object recognition.