title: Spatial attention systems in spatial neglect.
abstract: It has been established that processes relating to 'spatial attention' are implemented at cortical level by goal-directed (top-down) and stimulus-driven (bottom-up) networks. Spatial neglect in brain-damaged individuals has been interpreted as a distinguished exemplar for a disturbance of these processes. The present paper elaborates this assumption. Functioning of the two attentional networks seem to dissociate in spatial neglect; behavioral studies of patients' orienting and exploration behavior point to a disturbed stimulus-driven but preserved goal-directed attention system. When a target suddenly appears somewhere in space, neglect patients demonstrate disturbed detection and orienting if it is located in contralesional direction. In contrast, if neglect patients explore a scene with voluntarily, top-down controlled shifts of spatial attention, they perform movements that are oriented into all spatial directions without any direction-specific disturbances. The paper thus argues that not the top-down control of spatial attention itself, rather a body-related matrix on top of which this process is executed, seems affected. In that sense, the traditional role of spatial neglect as a stroke model for 'spatial attention' requires adjustment. Beyond its insights into the human stimulus-driven attentional system, the disorder most notably provides vistas in how our brain encodes topographical information and organizes spatially oriented action - including the top-down control of spatial attention - in relation to body position.
authors.affiliation: Center of Neurology, Division of Neuropsychology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; Department of Psychology, University of South Carolina, Columbia, SC, USA. Electronic address: Karnath@uni-tuebingen.de.
authors.forename: Hans-Otto
authors.initials: HO
authors.lastname: Karnath
mesh_terms: D001288:Attention / Q000502:physiology*; D001828:Body Image; D001921:Brain / Q000503:physiopathology*; D006040:Goals; D006801:Humans; D010468:Perceptual Disorders / Q000209:etiology / Q000503:physiopathology*; D011596:Psychomotor Disorders / Q000209:etiology / Q000503:physiopathology; D013028:Space Perception / Q000502:physiology*; D065855:Spatial Processing / Q000502:physiology; D020521:Stroke / Q000150:complications
keywords: Attention; Dorsal; Egocentric; Eye movements; Human; Reference frames; Space representation; Spatial neglect; Stroke; Top-down control; Ventral