Brain-behavior correlations in hemispatial neglect using CT and SPECT

Leibovitch, Farrell S.; Black, Sandra E.; Caldwell, Curtis; Ebert, Patricia; Ehrlich, Lisa; Szalai, John Paul

doi:10.1212/wnl.50.4.901

Cited by 169 publications

(92 citation statements)

References 13 publications

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“…In humans, neglect is characterized by defective orienting toward stimuli in the space contralateral to a unilateral cerebral lesion causing, among others, ipsilesional bias in the TOJ task Robertson, Mattingley, Rorden & Driver, 1998). The lesion is most frequently located in the right hemisphere, comprising the right inferior parietal lobe (Doricchi & Tomaiuolo, 2003;Mort et al, 2003;Vallar & Perani, 1986) and the underlying white matter connecting parietal and frontal areas (Doricchi & Tomaiuolo, 2003;Leibovitch et al, 1998;Gaffan & Hornak, 1997). Because neglect can appear independently of primary sensory or motor deficits, it was proposed that the main pathophysiological cause of the syndrome is the functional disruption in the damaged hemisphere of the neural network underpinning the multimodal coding of contralesional space.…”

Section: Discussionmentioning

confidence: 99%

Effects of Vestibular Rotatory Accelerations on Covert Attentional Orienting in Vision and Touch

Figliozzi

Guariglia

Silvetti

et al. 2005

Journal of Cognitive Neuroscience

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Abstract& Peripheral vestibular organs feed the central nervous system with inputs favoring the correct perception of space during head and body motion. Applying temporal order judgments (TOJs) to pairs of simultaneous or asynchronous stimuli presented in the left and right egocentric space, we evaluated the influence of leftward and rightward vestibular rotatory accelerations given around the vertical head-body axis on covert attentional orienting. In a first experiment, we presented visual stimuli in the left and right hemifield. In a second experiment, tactile stimuli were presented to hands lying on their anatomical side or in a crossed position across the sagittal body midline. In both experiments, stimuli were presented while normal subjects suppressed or did not suppress the vestibulo-ocular response (VOR) evoked by head-body rotation. Independently of VOR suppression, visual and tactile stimuli presented on the side of rotation were judged to precede simultaneous stimuli presented on the side opposite the rotation. When limbs were crossed, attentional facilitatory effects were only observed for stimuli presented to the right hand lying in the left hemispace during leftward rotatory trials with VOR suppression. This result points to spatiotopic rather than somatotopic influences of vestibular inputs, suggesting that cross-modal effects of these inputs on tactile ones operate on a representation of space that is updated following arm crossing. In a third control experiment, we demonstrated that temporal prioritization of stimuli presented on the side of rotation was not determined by response bias linked to spatial compatibility between the directions of rotation and the directional labels used in TOJs (i.e., ''left'' or ''right'' first). These findings suggest that during passive rotatory head-body accelerations, covert attention is shifted toward the direction of rotation and the direction of the fast phases of the VOR. &

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Section: Discussionmentioning

confidence: 99%

Effects of Vestibular Rotatory Accelerations on Covert Attentional Orienting in Vision and Touch

Figliozzi

Guariglia

Silvetti

et al. 2005

Journal of Cognitive Neuroscience

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“…More precisely, the crucial area is the inferior parietal lobule (supramarginal gyrus, Brodmann's area, BA 40) at the temporo-parietal junction [32,33]. Lesions localised more posteriorly in the occipital regions, or more superiorly in the superior parietal lobule bring about visual field deficits [32] or a deficit of reaching (optic ataxia), without neglect [34].…”

Section: Trends In Cognitive Sciencesmentioning

confidence: 99%

Spatial cognition: evidence from visual neglect

Halligan

Fink

Marshall

et al. 2003

Trends in Cognitive Sciences

503

274

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Recent work on human attention and representational systems has benefited from a growing interplay between research on normal attention and neuropsychological disorders such as visual neglect. Research over the past 30 years has convincingly shown that, far from being a unitary condition, neglect is a protean disorder whose symptoms can selectively affect different sensory modalities, cognitive processes, spatial domains and coordinate systems. These clinical findings, together with those of functional neuroimaging, have increased knowledge about the anatomical and functional architecture of normal subsystems involved in spatial cognition. We provide a selective overview of how recent investigations of visual neglect are beginning to elucidate the underlying structure of spatial processes and mental representations.Once considered a unitary syndrome, it is now accepted that visuospatial neglect results from the interplay of damage to several different cognitive processes [1,2]. Even within such relatively simple tasks as copying or spontaneous drawing, patients show many qualitatively distinct patterns of omission and distortion in 'left' space [3].Deficits of attention, intention, global-local processing, spatial memory and mental representation can all contribute to the clinical picture of neglect, which accordingly cannot be traced back to the disruption of a single supramodal process [1,4]. Many of the symptoms traditionally ascribed to left neglect share little in common other than a contra-lesional gradient of increasing impairment, with comparatively well -preserved performance on the ipsilesional (right) side of space [1,5].Although characterising and remediating the clinical condition [1,2,5] are clearly crucial, the primary interest for cognitive neuroscience is how conditions such as visual neglect can inform existing cognitive theory and functional anatomy. That an abnormal bias towards one side of space can exist in the absence of contralateral peripheral sensory or motor loss (e.g. visual field losses or hemi-paralysis) suggests that impairment to higher level processes must be involved. The standard approach taken by cognitive neuropsychology characterises complex mental processes as information-processing systems with separate but interconnected components. Some of the informationprocessing stages involved in visual object recognition (see Fig. 1) illustrate the potential levels and links where lateralised deficits can arise after brain damage.This model charts the processing routes from preattentive assignment of simple structural features (i.e. without the need for focused attention and conscious awareness) to post-attentional integration of local and global processing (involving selective attention and conscious awareness) and the assignment of relevant spatial frames of reference prior to recognition and naming.

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“…[1][2][3][4][5] But neglect may also occur after lesions to other regions, including areas in the frontal lobe. 3,6 -10 Various studies have documented that lesions restricted to the right basal ganglia lead to an asymmetry in space exploration and a failure to react or respond to stimuli located in the contralateral hemispace.…”

mentioning

confidence: 99%

“…3,6 -10 Various studies have documented that lesions restricted to the right basal ganglia lead to an asymmetry in space exploration and a failure to react or respond to stimuli located in the contralateral hemispace. 2,[11][12][13][14][15][16][17][18] Most of these studies examine patients with neglect as a consequence of stroke and it has been controversial if hemispatial neglect following subcortical lesions are the consequence of associated cortical dysfunction not visible by structural computer tomography or conventional magnetic resonance imaging (MRI). 15,19,20 In support of this hypothesis, several studies have shown cortical hypoperfusion in patients with neglect associated with subcortical stroke using MR perfusion-weighted imaging or single photon emission computed tomography (SPECT).…”

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confidence: 99%

Change in artistic expression related to subthalamic stimulation

Witt¹,

Krack²,

Deuschl³

2006

J Neurol

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While the role of frontal and parietal cortex in spatial orientation has been studied extensively, the contribution of the basal ganglia and especially the subthalamic nucleus to spatial orientation remains less clear. Here we use subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) as a reversible model of functional lesioning to evaluate the influence of the STN in extrapersonal space orientation. To this end, 12 PD patients were examined 1 year after implantation of DBS electrodes in the STN after overnight withdrawal of L-dopa. Patients were tested in a pseudorandomized order while both stimulators, the right only, the left only, or no stimulator, were switched on. Patients performed line bisection and a reaction time task responding to stimuli of the middle, the left, and the right extrapersonal space. A separate assessment of the right and left hand responding to visual stimuli in each hemispace made it possible to distinguish hemispatial and hemimotor impairments. No asymmetries in space orientation were found when both stimulators were switched OFF, when both stimulators were switched ON, and when only the right stimulator was switched ON. When only the left subthalamic stimulation was switched ON, the reaction times of both hands to visual stimuli in the left extrapersonal hemispace increased significantly and the line bisection test showed a significant orientation to the right. These results lead to the conclusion that the STN and its cortical projections influence the network involved in visuospatial orientation. These patterns of symptoms of neglect demonstrate the influence of the STN on the attentional system of the nondominant hemisphere.

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Brain-behavior correlations in hemispatial neglect using CT and SPECT

Abstract: Damage in the parietal and anterior cingulate cortex and posterior white matter fiber bundles correlated with hemispatial neglect. Combining structural- and functional-imaging techniques with neurobehavioral analysis can elucidate brain-behavior relationships.

Cited by 169 publications

References 13 publications

Effects of Vestibular Rotatory Accelerations on Covert Attentional Orienting in Vision and Touch

Effects of Vestibular Rotatory Accelerations on Covert Attentional Orienting in Vision and Touch

Spatial cognition: evidence from visual neglect

Change in artistic expression related to subthalamic stimulation

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