کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10467677 | 925839 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The relationship of visual extinction to luminance-contrast imbalances between left and right hemifield stimuli
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موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
علوم اعصاب رفتاری
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چکیده انگلیسی
Visual extinction was investigated in six right brain-damaged patients with left visual neglect, using a psychophysical paradigm. Orientation discrimination thresholds were determined for both left and right hemifield gratings presented either in isolation or simultaneously with a contralateral distractor grating. To minimize the influence of possible sensory-perceptual deficits, the luminances of both target and distractor gratings were chosen to be 20 times the luminances necessary to discriminate between horizontal and vertical grating orientations. When the visibility of target and distractor gratings was subjectively equalized in this way, neglect patients still showed a significant extinction effect, i.e. a significant interference of the right hemifield distractor with left hemifield orientation sensitivity. By manipulating the luminances of left and right hemifield gratings during bilateral simultaneous stimulus presentation, we demonstrated the role of luminance-contrast imbalances in eliciting visual extinction. Both decreasing the right distractor luminance and increasing the left target stimulus luminance resulted in an elimination of the observed extinction effects. These results show that not the absolute salience of one of two simultaneously presented stimuli, but the relative salience of both stimuli, is the crucial factor for inducing extinction.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuropsychologia - Volume 43, Issue 4, 2005, Pages 542-553
Journal: Neuropsychologia - Volume 43, Issue 4, 2005, Pages 542-553
نویسندگان
Sarah Geeraerts, Karla Michiels, Christophe Lafosse, Erik Vandenbussche, Karl Verfaillie,