کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8795339 1603157 2018 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mismatched summation mechanisms in older adults for the perception of small moving stimuli
ترجمه فارسی عنوان
مکانیزم جمعآوری نشده در بزرگسالان بزرگسال برای درک محرکهای در حال حرکت کوچک
کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی سیستم های حسی
چکیده انگلیسی
Previous studies have found evidence for reduced cortical inhibition in aging visual cortex. Reduced inhibition could plausibly increase the spatial area of excitation in receptive fields of older observers, as weaker inhibitory processes would allow the excitatory receptive field to dominate and be psychophysically measureable over larger areas. Here, we investigated aging effects on spatial summation of motion direction using the Battenberg summation method, which aims to control the influence of locally generated internal noise changes by holding overall display size constant. This method produces more accurate estimates of summation area than conventional methods that simply increase overall stimulus dimensions. Battenberg stimuli have a checkerboard arrangement, where check size (luminance-modulated drifting gratings alternating with mean luminance areas), but not display size, is varied and compared with performance for a full field stimulus to provide a measure of summation. Motion direction discrimination thresholds, where contrast was the dependent variable, were measured in 14 younger (24-34 years) and 14 older (62-76 years) adults. Older observers were less sensitive for all check sizes, but the relative sensitivity across sizes, also differed between groups. In the older adults, the full field stimulus offered smaller performance improvements compared to that for younger adults, specifically for the small checked Battenberg stimuli. This suggests aging impacts on short-range summation mechanisms, potentially underpinned by larger summation areas for the perception of small moving stimuli.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vision Research - Volume 142, January 2018, Pages 52-57
نویسندگان
, , , ,