title: The right hemisphere is dominant in organization of visual search-A study in stroke patients.
abstract: Cancellation tasks are widely used for diagnosis of lateralized attentional deficits in stroke patients. A disorganized fashion of target cancellation has been hypothesized to reflect disturbed spatial exploration. In the current study we aimed to examine which lesion locations result in disorganized visual search during cancellation tasks, in order to determine which brain areas are involved in search organization. A computerized shape cancellation task was administered in 78 stroke patients. As an index for search organization, the amount of intersections of paths between consecutive crossed targets was computed (i.e., intersections rate). This measure is known to accurately depict disorganized visual search in a stroke population. Ischemic lesions were delineated on CT or MRI images. Assumption-free voxel-based lesion-symptom mapping and region of interest-based analyses were used to determine the grey and white matter anatomical correlates of the intersections rate as a continuous measure. The right lateral occipital cortex, superior parietal lobule, postcentral gyrus, superior temporal gyrus, middle temporal gyrus, supramarginal gyrus, inferior longitudinal fasciculus, first branch of the superior longitudinal fasciculus (SLF I), and the inferior fronto-occipital fasciculus, were related to search organization. To conclude, a clear right hemispheric dominance for search organization was revealed. Further, the correlates of disorganized search overlap with regions that have previously been associated with conjunctive search and spatial working memory. This suggests that disorganized visual search is caused by disturbed spatial processes, rather than deficits in high level executive function or planning, which would be expected to be more related to frontal regions.
authors.affiliation: Brain Center Rudolf Magnus and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, The Netherlands.
authors.forename: Antonia F
authors.initials: AF
authors.lastname: Ten Brink
authors.affiliation: Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: J Matthijs
authors.initials: JM
authors.lastname: Biesbroek
authors.affiliation: Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Hugo J
authors.initials: HJ
authors.lastname: Kuijf
authors.affiliation: Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Van der Stigchel
authors.affiliation: Brain Center Rudolf Magnus and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, The Netherlands.
authors.forename: Quirien
authors.initials: Q
authors.lastname: Oort
authors.affiliation: Brain Center Rudolf Magnus and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, The Netherlands.
authors.forename: Johanna M A
authors.initials: JM
authors.lastname: Visser-Meily
authors.affiliation: Brain Center Rudolf Magnus and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, The Netherlands; Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands. Electronic address: t.c.w.nijboer@uu.nl.
authors.forename: Tanja C W
authors.initials: TC
authors.lastname: Nijboer
mesh_terms: D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000000981:diagnostic imaging / Q000209:etiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology*; D015898:Tomography Scanners, X-Ray Computed; D014795:Visual Pathways / Q000000981:diagnostic imaging / Q000473:pathology
keywords: Cancellation; Lesion-symptom mapping; Search organization; Stroke; Visual search