Focal and global attention modulate the expression of visuo-spatial neglect: a case study.
We report a case of severe left visuo-spatial neglect consequent upon right-hemisphere stroke. In Experiment 1, we show that while the patient bisects lines significantly to the right of true centre, he is extremely accurate in placing a mark at the centre of an equivalent outlined square. Experiment 2 confirms that the lateral and radial accuracy obtained in the latter (square) task cannot be predicted from the lateral and radial displacements found in horizontal and vertical (radial) line bisection; the experiment also shows that the individual horizontal lines of a square can be bisected significantly more accurately than the same lines presented individually. Experiment 3 shows that the crucial figural component requisite for the accurate estimation of lateral extent is a large vertical (radial) line in right space. The obtained figural modulation of neglect is consistent with the model in which a large, unitary stimulus in right space engages and enhances the lesioned right hemisphere's intrinsic capacity to deploy global attention.
Halligan
P W
PW
Rivermead Rehabilitation Centre, Oxford, U.K.
Marshall
J C
JC
D001288:Attention / Q000502:physiology*; D001925:Brain Damage, Chronic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D002540:Cerebral Cortex / Q000503:physiopathology; D002544:Cerebral Infarction / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D004215:Distance Perception / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology*; D006423:Hemianopsia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D006429:Hemiplegia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D014057:Tomography, X-Ray Computed