The cortical substrate of visual extinction.

Abstract

Neuroimaging studies investigated the attentional systems of the human brain revealing two networks, one for voluntary allocation of attention and another for stimulus-driven attentional processes. Whereas lesions of the latter system were supposed to lead to spatial neglect, we show that such lesions rather are typical for the occurrence of visual extinction. Extinction describes the inability of brain-damaged patients to detect a contralesional target in the presence of a competing ipsilesional stimulus. In a sample of consecutively admitted patients with right hemisphere stroke, we found dissociable cortical substrates for spatial neglect and visual extinction. There was a surprising congruency between the typical lesion site in patients with extinction and the activation clusters found in previous neuroimaging studies of healthy subjects. The results show that the temporo-parietal junction (TPJ), considered to be a crucial part of the stimulus-driven attentional network, is the neural substrate of visual extinction.