Dissociation of body-centered and stimulus-centered representations in unilateral neglect

Ota, Hisaaki; Fujii, Toshikatsu; Suzuki, Kyoko; Fukatsu, Reiko; Yamadori, Atsushi

doi:10.1212/wnl.57.11.2064

Cited by 168 publications

(157 citation statements)

References 39 publications

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“…Tests of hemispatial neglect included the following: copying a scene of two trees, a house, and a fence (Ogden, 1985); modifications of the line cancellation test (Albert, 1973); line bisection, in which the page was presented 45°to the left and 45°to the right of the midsagittal plane and at the midsagittal plane of the viewer (10 -12 inches from the trunk); reading sentences; and a gap-detection test (Ota et al, 2001). In the gap-detection test, a page of 30 circles was presented: 10 circles had a gap on the left side, 10 had a gap on the right side, and 10 had no gap.…”

Section: Methodsmentioning

confidence: 99%

“…Patients with egocentric neglect may omit items on the left side of the page because these items fall on their left sides. These types of neglect can be distinguished with tasks involving stimuli with left and right targets (e.g., left or right gaps in circles) presented across the page (Ota et al, 2001). Patients with allocentric neglect miss left targets within stimuli on both sides of the page; patients with egocentric neglect detect both left and right targets within stimuli on the right but fail to respond to stimuli on the left side of the page.…”

Section: Introductionmentioning

confidence: 99%

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Anatomy of Spatial Attention: Insights from Perfusion Imaging and Hemispatial Neglect in Acute Stroke

Hillis¹,

Newhart²,

Heidler³

et al. 2005

J. Neurosci.

292

223

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The site of lesion responsible for left hemispatial neglect after stroke has been intensely debated recently. Some studies provide evidence that right angular lesions are most likely to cause left neglect, whereas others indicate that right superior temporal lesions are most likely to cause neglect. We examine two potential accounts of the conflicting results: (1) neglect could result from cortical dysfunction beyond the structural lesion in some studies; and (2) different forms of neglect with separate neural correlates have been included in different proportions in separate studies. To evaluate these proposals, we studied 50 patients with acute right subcortical infarcts using tests of hemispatial neglect and magnetic resonance diffusion-weighted and perfusion-weighted imaging performed within 48 h of onset of symptoms. Left "allocentric" neglect (errors on the left sides of individual stimuli, regardless of location with respect to the viewer) was most strongly associated with hypoperfusion of right superior temporal gyrus (Fisher's exact test; p Ͻ 0.0001), whereas left "egocentric" neglect (errors on the left of the viewer) was most strongly associated with hypoperfusion of the right angular gyrus ( p Ͻ 0.0001). Patients without cortical hypoperfusion showed no hemispatial neglect. Because the patients did not have cortical infarcts, our data show that neglect can be caused by hypoperfused dysfunctional tissue not detectable by structural magnetic resonance imaging. Moreover, different forms of neglect were associated with different sites of cortical hypoperfusion. Results help explain conflicting results in the literature and contribute to the understanding of spatial attention and representation in the human brain.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anatomy of Spatial Attention: Insights from Perfusion Imaging and Hemispatial Neglect in Acute Stroke

Hillis¹,

Newhart²,

Heidler³

et al. 2005

J. Neurosci.

292

223

View full text Add to dashboard Cite

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“…II (a) is that, here, the patient has not missed out the left side of the overall scene, but rather the respective left sides of the two objects present [14,75]. Double dissociations between the two frames of reference show that they can function independently of each other [76,77].…”

Section: Different Frames Of Referencementioning

confidence: 97%

Spatial cognition: evidence from visual neglect

Halligan

Fink

Marshall

et al. 2003

Trends in Cognitive Sciences

502

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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“…Tests of hemispatial neglect included the following: copy a scene of two trees, a house, and a fence (Ogden, 1985); modification of the line cancellation test (Albert, 1973); line bisection, in which the page was presented 45° to the left and 45° to the right of the midsagittal plane and at the midsagittal plane of the viewer (25-30 cm from the trunk); clock copy; reading words; reading sentences; oral spelling; and a gap-detection test (Ota et al, 2001). In the gap-detection test, a page of 30 circles was presented: 10 circles had a gap on the left side, 10 had a gap on the right side, and 10 had no gap.…”

Section: Neglect Testingmentioning

confidence: 99%

“…Two forms of allocentric USN have been described. The first, stimulus-centered USN, is characterized by errors on the contralesional side of the visual stimulus, irrespective of the location of the stimulus with respect to the viewer (Cubelli et al, 1991;Haywood & Coltheart, 2000;Hillis & Caramazza, 1991& 1995a,Nichelli et al, 1993Ota et al, 2001,Subbiah & Caramazza, 2000. To illustrate, patients with right stimuluscentered USN might read feet as "feel" 1 when presented left to right, feet as "feet" when presented vertically, or feet as "meet" when mirror reversed, because the right side of the stimulus changes in each instance.…”

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confidence: 99%

Right hemispatial neglect: Frequency and characterization following acute left hemisphere stroke

Kleinman

Newhart

Davis

et al. 2007

Brain and Cognition

137

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The frequency of various types of unilateral spatial neglect and associated areas of neural dysfunction after left hemisphere stroke are not well characterized. Unilateral spatial neglect (USN) in distinct spatial reference frames have been identified after acute right, but not left hemisphere stroke. We studied 47 consecutive right handed patients within 48 hours of left hemisphere stroke to determine the frequency and distribution of types of right USN using cognitive testing and MRI imaging. The distribution of USN types was different from the previously reported distribution following acute right hemisphere stroke. In this left hemisphere stroke population, allocentric neglect was more frequent than egocentric neglect.

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Dissociation of body-centered and stimulus-centered representations in unilateral neglect

Cited by 168 publications

References 39 publications

Anatomy of Spatial Attention: Insights from Perfusion Imaging and Hemispatial Neglect in Acute Stroke

Anatomy of Spatial Attention: Insights from Perfusion Imaging and Hemispatial Neglect in Acute Stroke

Spatial cognition: evidence from visual neglect

Right hemispatial neglect: Frequency and characterization following acute left hemisphere stroke

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