A Parietofrontal Network for Spatial Awareness in the Right Hemisphere of the Human Brain

Patients with lesions of the right hemisphere often show signs of left-sided unilateral neglect. Left-sided neglect may impair the ability of patients to live independently and entails a poor functional outcome. When exploring a visual scene, patients with left-sided neglect fail to pay attention to left-sided objects. They do not eat from the left part of their dish, they bump their wheelchair into obstacles situated on their left, and they have a tendency to look to right-sided details as soon as a visual scene unfolds, as if their attention were “magnetically” attracted by these details.[1] On visuospatial testing, they fail to cancel or describe left-sided targets in search tasks, deviate rightward when bisecting horizontal lines, and fail to copy the left part of drawings[1,2] (Figure 1).The study of left-sided neglect is important for neuroscientists to understand the brain mechanisms underlying spatial awareness. From the clinical point of view, research on neglect can ameliorate the diagnosis by devising appropriate visuospatial tests, clarify the prognostic factors for individual patients with particular patterns of impairment, and allow the development of rationa strategies of rehabilitation. Despite decades of research, however, the lesional bases of neglect within the right hemisphere still remain controversial