Enhanced visual spatial attention ipsilateral to rTMS-induced 'virtual lesions' of human parietal cortex.
The breakdown of attentional mechanisms after brain damage can have drastic behavioral consequences, as in patients suffering from spatial neglect. While much research has concentrated on impaired attention to targets contralateral to sites of brain damage, here we report the ipsilateral enhancement of visual attention after repetitive transcranial magnetic stimulation (rTMS) of parietal cortex at parameters known to reduce cortical excitability. Normal healthy subjects received rTMS (1 Hz, 10 mins) over right or left parietal cortex. Subsequently, detection of visual stimuli contralateral to the stimulated hemisphere was consistently impaired when stimuli were also present in the opposite hemifield, mirroring the extinction phenomenon commonly observed in neglect patients. Additionally, subjects' attention to ipsilateral targets improved significantly over normal levels. These results underline the potential of focal brain dysfunction to produce behavioral improvement and give experimental support to models of interhemispheric competition in the distributed brain network for spatial attention.
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Boston University School of Medicine, Department of Anatomy and Neurobiology, 700 Albany Street W746, Boston, Massachusetts 02118, USA. claush@bu.edu
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Pascual-Leone
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D000328:Adult; D001288:Attention / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D004558:Electric Stimulation; D006801:Humans; D008280:Magnetics; D008297:Male; D009462:Neurology / Q000379:methods; D010296:Parietal Lobe / Q000502:physiology*; D010468:Perceptual Disorders / Q000503:physiopathology / Q000523:psychology; D012016:Reference Values; D013028:Space Perception / Q000502:physiology*; D014584:User-Computer Interface; D014796:Visual Perception / Q000502:physiology*