Anti-extinction Following Unilateral Parietal Damage

Abstract

Following unilateral damage to the parietal cortex, extinction of sensory events on the side of space opposite the lesion frequently occurs: A contralesional event is detected when it occurs alone, but missed when it is accompanied by an ipsilesional event. We describe a patientwith left visuospatial neglect subsequent to a right parietal infarct, who shows the opposite of this typical extinction pattern: On brief visual presentations, he consistently shows better detection and identification of contralesional targets when they appear simultaneously with an ipsilesional target, compared to when the contralesional target appears alone. This benefitfor contralesional targets on simultaneous presentation is found most clearly when the same task is performed with both contra- and ipsilesional items. These findings first provide a very clear demonstration of neglect in the absence of extinction. Second, our results demonstrate that visuospatial neglect can be mitigated by non-perceptual task variables.