The contribution of spatial remapping impairments to unilateral visual neglect

Pisella, L and Mattingley, JB (2004) The contribution of spatial remapping impairments to unilateral visual neglect. Neuroscience And Biobehavioral Reviews, 28 2: 181-200. doi:10.1016/j.neubiorev.2004.03.003


Author Pisella, L
Mattingley, JB
Title The contribution of spatial remapping impairments to unilateral visual neglect
Journal name Neuroscience And Biobehavioral Reviews   Check publisher's open access policy
ISSN 0149-7634
Publication date 2004-01-01
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1016/j.neubiorev.2004.03.003
Volume 28
Issue 2
Start page 181
End page 200
Total pages 20
Place of publication Oxford
Publisher Pergamon-elsevier Science Ltd
Language eng
Abstract Left visual neglect following right hemisphere damage is a heterogeneous phenomenon, in which several underlying impairments have been identified. Despite recent advances in understanding the neural and cognitive bases of these impairments, current theories of neglect, particularly those that emphasise attentional deficits, do not explain a number of phenomena, including: 'Ipsilesional' neglect after left orienting Positive or 'productive' manifestations Spatial transposition errors Mislocalisations Revisiting behaviour during visual search Lack of awareness for objects toward the contralesional side of space We propose that these manifestations of neglect can be accounted for by an additional underlying disorder of spatial remapping due to parietal dysfunction. In primary visual areas, retinotopic maps are renewed and thus overwritten at each new ocular fixation. Remapping processes operating in higher-level oculocentric visual maps of the parietal cortex ensure visual integration of these successive retinal images over time and space, by creating a constantly updated representation of stimulus locations in terms of distance and direction from the fovea. They consist in the storage, refreshment and re-localization of the different components of the visual scene that are successively attended during its exploration, and provide spatial constancy of visual perception and a spatial buffer for working memory [Cereb Cortex 5 (1995) 470; Visual Cogn 7 (2000) 17]. We begin this article by reviewing theoretical and experimental arguments that have highlighted the importance of parietal remapping processes in maintaining an accurate representation of space across saccadic shifts. We then focus on findings from the double-step saccade task, [Ann Neurol 38 (1995) 739] as a basis for our model of the role of remapping impairments in many of the symptoms of neglect. From these results, remapping impairments would be demonstrated when a saccade has to be guided across the midline after having fixated an object in either the left or right visual field for patients with either left- or right-side parietal lesions. In addition, patients with right-side lesions will have remapping impairments within the left visual field following a saccade to a left-side target (see Fig. 5). In a large pan of the article, we seek to build our hypothesis based on this basic model and more speculative assumptions supported with extensive evidence from the literature. (C) 2004 Elsevier Ltd. All rights reserved.
Keyword Behavioral Sciences
Neurosciences
spatial remapping
visual representation
neurones
spatial hemineglect
parietal cortex
Common Attentional Mechanism
Lateral Intraparietal Area
Posterior Parietal Cortex
Line Bisection Judgments
Right-hemisphere Damage
Visuospatial Neglect
Working-memory
Hemispatial Neglect
Eye-movements
Cerebral Lesions
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes This document is a journal review.

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: Excellence in Research Australia (ERA) - Collection
Queensland Brain Institute Publications
 
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Created: Wed, 17 Oct 2007, 22:56:05 EST