The anatomy of neglect without hemianopia: a key role for parietal-frontal disconnection?

We investigated the anatomical correlates of chronic unilateral neglect in right brain damaged patients with no visual field defects. Independently from basal ganglia or thalamus involvement, neglect patients had a subcortical area of maximal lesion overlap (maxov) in the superior longitudinal fasciculus (SLF). Neglect patients without lesion of subcortical nuclei had an additional maxov area in the rostralmost limit of the supramarginal gyrus (SmG). Patients without neglect showed a maxov area in the corticospinal tract with no involvement of the SLF or SmG. These findings call attention to the role of parietal-frontal disconnection in the pathogenesis of neglect. This disconnection can make neglect generalised and enduring also in patients suffering only partial damage of the parietal-temporal cortex, and who would otherwise show more selective attentional impairments.