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ERIC Number: EJ864656
Record Type: Journal
Publication Date: 2009-Oct
Pages: 10
Abstractor: As Provided
Reference Count: 0
ISBN: N/A
ISSN: ISSN-0898-929X
The Role of the Parietal Lobe in Visual Extinction Studied with Transcranial Magnetic Stimulation
Battelli, Lorella; Alvarez, George A.; Carlson, Thomas; Pascual-Leone, Alvaro
Journal of Cognitive Neuroscience, v21 n10 p1946-1955 Oct 2009
Interhemispheric competition between homologous areas in the human brain is believed to be involved in a wide variety of human behaviors from motor activity to visual perception and particularly attention. For example, patients with lesions in the posterior parietal cortex are unable to selectively track objects in the contralesional side of visual space when targets are simultaneously present in the ipsilesional visual field, a form of visual extinction. Visual extinction may arise due to an imbalance in the normal interhemispheric competition. To directly assess the issue of reciprocal inhibition, we used fMRI to localize those brain regions active during attention-based visual tracking and then applied low-frequency repetitive transcranial magnetic stimulation over identified areas in the left and right intraparietal sulcus to asses the behavioral effects on visual tracking. We induced a severe impairment in visual tracking that was selective for conditions of simultaneous tracking in both visual fields. Our data show that the parietal lobe is essential for visual tracking and that the two hemispheres compete for attentional resources during tracking. Our results provide a neuronal basis for visual extinction in patients with parietal lobe damage.
MIT Press. Circulation Department, Five Cambridge Center, Cambridge, MA 02142. Tel: 617-253-2889; Fax: 617-577-1545; e-mail: journals-orders@mit.edu; Web site: http://www.mitpressjournals.org/loi/jocn
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A