Posterior parietal cortex and visuospatial control in near and far space

Neuropsychological studies of patients with visuospatial neglect have shown differences in perceptual deficits for information in near space (i.e. near to the body) and information in far space. It has been suggested that among the many areas of the human brain, a number of areas are associated with a set of spatial maps specialized for visuospatial control related to this spatial distinction. This paper reviews how parietal cortex is thought to be involved in visuospatial neglect in relation to its control of visuospatial attention in the left and right visual fields and at different viewing distances. In particular, the importance of regions of the parietal cortex in the pathogenesis of neglect and in spatial attention and perception is discussed. Parietal cortex may control different distributions of attention across space by allocating specific attentional resources in near and far space while also showing attentional asymmetry across visual fields. Transcranial magnetic stimulation (TMS) as a technique offers the advantage of examining the direct behavioral effect of disruption of many of these areas with excellent temporal and spatial resolution. We discuss the use of TMS and the insights it may offer regarding the roles of these areas in neglect as well as normal visuospatial perception.