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Sustained attention deficits in time and space
ROBERTSON, I. H. & MANLY, T.
In G. W. Humphreys, J. Duncan & A. Treisman (Eds.) Attention, space and action: Studies in cognitive neuroscience, pp297-310. Oxford: Oxford University Press
Year of publication:
We review critically the influential framework of attentional systems developed by Posner and Petersen (1990). Their proposal that three independent supramodal attentional control systems exist in the brain--selection, alertness and spatial attention respectively--is examined in the light of evidence accumulated over the last decade. We conclude that while evidence for differentiable supramodal selection and alertness systems is quite strong, the notion of a posterior supramodal spatial attention system centred in the parietal lobes is much weaker. We review evidence showing that unilateral neglect consequent on parietal lesions is both strongly associated with non-lateralised attentional deficits, and strongly modifiable by manipulation of these non-spatial variables. Spatial selective attention may be better conceived of as an emergent property of competition between distributed but integrated representations of objects and space between the two hemispheres. The role of the parietal lobes in spatial selection may be related to the integration of cross-modal representations and motor preparation in the organisation of responses towards the environment. But the parietal lobe of the right hemisphere appears to have an additional, but as yet inadequately specified role, in the maintenance of the alert state over time and other non-lateralised aspects of attention.