A critical review of the role of impaired spatial remapping processes in spatial neglect.

OBJECTIVE: Unilateral spatial neglect is a multi-faceted syndrome that arises from brain lesions, typically in the right hemisphere, and is characterized by the failure to attend or respond to stimuli in contralesional space. Here, we expand on the proposal that one deficit contributing to the diverse symptoms in neglect involves spatial remapping processes. Spatial remapping is required to maintain a stable visual representation despite frequent eye movements that change the retinal image. Neglect patients' lesions may disrupt the transfer of this representation across saccades, resulting in the loss of spatial information in working memory or even awareness of an object's presence.

METHOD: In this review, we will characterize the neglect syndrome and its anatomical origins, describe spatial remapping in healthy individuals, then focus on how impairments of remapping and spatial working memory could contribute to some reported neglect symptoms. Finally, we will discuss the effectiveness of a rehabilitation method known as prism adaptation for alleviating visual spatial symptoms in neglect patients in relation to spatial remapping performance.

CONCLUSIONS: The heterogeneity of spatial neglect makes it difficult to pinpoint a single underlying dysfunction or causal lesion. Given the number of brain regions that may be damaged across neglect patients, it is likely that many different processes contribute to the manifested attentional symptoms. In this review, we highlight the role of spatial remapping mechanisms subserved by posterior parietal cortex as one of the underlying deficits leading to visual spatial neglect.