Ipsilateral influences on contralateral processing in neglect patients

Abstract

This article addresses the question of whether visual neglect of objects, as evidenced in a naming task, is influenced by the meaningfulness of the ipsilateral side of the stimuli. In the first experiment, six right-lesioned neglect subjects were asked to name drawings of common objects, the meaning of which could be ascertained by discovering the left part. The results indicate that neglect was indeed influenced by the left part of stimuli. Yet, given that some aspects of the results could be due to a ceiling effect and in order to examine if a similar influence of the left part of the stimuli could be observed in a situation that prevent eye movements, a second experiment with the same material was administered to ten normal and three neglect subjects under tachistoscopic condition. The results of the second experiment were very similar to those obtained in free-viewing condition. The theoretical interpretation stresses contextual aspects of neglect symptoms and suggests the influence of top-down adaptative processing mechanisms acting on overt as well as internal selective processes.