84
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Role of right posterior parietal cortex in maintaining attention to spatial locations over time

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Recent models of human posterior parietal cortex (PPC) have variously emphasized its role in spatial perception, visuomotor control or directing attention. However, neuroimaging and lesion studies also suggest that the right PPC might play a special role in maintaining an alert state. Previously, assessments of right-hemisphere patients with hemispatial neglect have revealed significant overall deficits on vigilance tasks, but to date there has been no demonstration of a deterioration of performance over time—a vigilance decrement—considered by some to be a key index of a deficit in maintaining attention. Moreover, sustained attention deficits in neglect have not specifically been related to PPC lesions, and it remains unclear whether they interact with spatial impairments in this syndrome. Here we examined the ability of right-hemisphere patients with neglect to maintain attention, comparing them to stroke controls and healthy individuals. We found evidence of an overall deficit in sustaining attention associated with PPC lesions, even for a simple detection task with stimuli presented centrally. In a second experiment, we demonstrated a vigilance decrement in neglect patients specifically only when they were required to maintain attention to spatial locations, but not verbal material. Lesioned voxels in the right PPC spanning a region between the intraparietal sulcus and inferior parietal lobe were significantly associated with this deficit. Finally, we compared performance on a task that required attention to be maintained either to visual patterns or spatial locations, matched for task difficulty. Again, we found a vigilance decrement but only when attention had to be maintained on spatial information. We conclude that sustaining attention to spatial locations is a critical function of the human right PPC which needs to be incorporated into models of normal parietal function as well as those of the clinical syndrome of hemispatial neglect.

          Related collections

          Most cited references87

          • Record: found
          • Abstract: not found
          • Article: not found

          The attention system of the human brain.

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Breakdown of functional connectivity in frontoparietal networks underlies behavioral deficits in spatial neglect.

            Spatial neglect is a syndrome following stroke manifesting attentional deficits in perceiving and responding to stimuli in the contralesional field. We examined brain network integrity in patients with neglect by measuring coherent fluctuations of fMRI signals (functional connectivity). Connectivity in two largely separate attention networks located in dorsal and ventral frontoparietal areas was assessed at both acute and chronic stages of recovery. Connectivity in the ventral network, part of which directly lesioned, was diffusely disrupted and showed no recovery. In the structurally intact dorsal network, interhemispheric connectivity in posterior parietal cortex was acutely disrupted but fully recovered. This acute disruption, and disrupted connectivity in specific pathways in the ventral network, strongly correlated with impaired attentional processing across subjects. Lastly, disconnection of the white matter tracts connecting frontal and parietal cortices was associated with more severe neglect and more disrupted functional connectivity. These findings support a network view in understanding neglect.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Effects of parietal injury on covert orienting of attention.

              The cognitive act of shifting attention from one place in the visual field to another can be accomplished covertly without muscular changes. The act can be viewed in terms of three internal mental operations: disengagement of attention from its current focus, moving attention to the target, and engagement of the target. Our results show that damage to the parietal lobe produces a deficit in the disengage operation when the target is contralateral to the lesion. Effects may also be found on engagement with the target. The effects of brain injury on disengagement of attention seem to be unique to the parietal lobe and do not appear to occur with our frontal, midbrain, and temporal control series. These results confirm the close connection between parietal lobes and selective attention suggested by single cell recording. They indicate more specifically the role that parietal function has on attention and suggest one mechanism of the effects of parietal lesions reported in clinical neurology.
                Bookmark

                Author and article information

                Journal
                Brain
                brainj
                brain
                Brain
                Oxford University Press
                0006-8950
                1460-2156
                March 2009
                21 January 2009
                21 January 2009
                : 132
                : 3
                : 645-660
                Affiliations
                1 UCL Institute of Cognitive Neuroscience, London, UK
                2 Imperial College London, UK
                3 UCL Institute of Neurology, London, UK
                Author notes
                Correspondence to: Paresh Malhotra, Division of Neurosciences and Mental Health, Imperial College London, Charing Cross Campus, St. Dunstan's Road, London W6 8RP, UK E-mail: p.malhotra@ 123456imperial.ac.uk
                Article
                awn350
                10.1093/brain/awn350
                2664449
                19158107
                9804a6b7-f836-40f8-b8a5-bd32634f438a
                © 2009 The Author(s)

                This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 11 June 2008
                : 6 November 2008
                : 28 November 2008
                Categories
                Original Articles

                Neurosciences
                attention,spatial memory,sustained attention,neglect,vigilance
                Neurosciences
                attention, spatial memory, sustained attention, neglect, vigilance

                Comments

                Comment on this article