دانلود مقاله ISI انگلیسی شماره 39748
عنوان فارسی مقاله

ادراک شکل ضمنی حفظ شده و انطباق جهت گیری در ادراکپریشی به صورت بصری

کد مقاله سال انتشار مقاله انگلیسی ترجمه فارسی تعداد کلمات
39748 2006 10 صفحه PDF سفارش دهید محاسبه نشده
خرید مقاله
پس از پرداخت، فوراً می توانید مقاله را دانلود فرمایید.
عنوان انگلیسی
Preserved implicit form perception and orientation adaptation in visual form agnosia
منبع

Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)

Journal : Neuropsychologia, Volume 44, Issue 10, 2006, Pages 1833–1842

کلمات کلیدی
تشخیص اشیا - آگاهی بصری - منطقه پس سری جانبی - قشر ویژوال
پیش نمایش مقاله
پیش نمایش مقاله ادراک شکل ضمنی حفظ شده و انطباق جهت گیری در ادراکپریشی به صورت بصری

چکیده انگلیسی

Visual form agnosia is mainly characterized by profound deficits in visual form and shape discrimination. Previous studies have shown that patients retain the capacity for coordinated motor behaviors, color naming and implicit letter perception. However, it is unknown to what extent other visual functions, such as implicit form and orientation perception, are preserved. To address these questions, we investigated a single visual form agnosic patient, X.F., in two distinct experiments. X.F.'s visual lesions were mainly localized in the bilateral occipitotemporal cortex, with the dorsal visual stream and early visual cortex largely spared. In Experiment 1, X.F. named the color of different forms across 12 blocks of trials. After the first six blocks, the combinations of a form with its color were changed and the new combination was presented for the remaining six blocks. X.F.'s reaction time increased during the switch block and was significantly greater than the overall RT changes between adjacent, non-switch blocks. This indicates that X.F. retained the ability to perceive changes in form despite her inability to discriminate the forms. In Experiment 2, X.F. showed selective orientation adaptation effects to different spatial frequencies; that is, her contrast threshold was significantly higher when the adapting and test orientations were the same than when they were orthogonal, although her orientation discrimination performance was severely impaired. These data provide evidence of a functional dissociation between explicit and implicit visual abilities, and suggest that the residual early visual cortex mediates form and orientation processing in the absence of awareness.

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