کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4035593 1263536 2006 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Evidence for elongated receptive field structure for mechanisms subserving stereopsis
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی سیستم های حسی
پیش نمایش صفحه اول مقاله
Evidence for elongated receptive field structure for mechanisms subserving stereopsis
چکیده انگلیسی

To study the spatial extent and shape of the binocular disparity mechanisms subserving depth perception, we employ the spatial summation paradigm of contrast threshold for front/back depth discrimination at a fixed binocular disparity. The stimuli were Gabor patches with disparity set at either 4 or 8 arcmin and spatial frequency set at an optimal value of 4 cy/deg. Contrast threshold was measured as a function of length and width of the Gabor patches to determine the aspect ratio of greatest efficiency. The space constant of the Gaussian envelope varied between 0.0375° and 0.9° in either vertical or horizontal directions, or both simultaneously. For vertical elongation of the Gabor patches, discrimination sensitivity improved by 4–6 dB for a doubling of the length of the Gabor patches, then reduced more slowly as the length further increased. However, extending the Gabor patches horizontally across cycles produced little or no sensitivity improvement. Instead, discrimination performance collapsed in a fashion that is incompatible with many models of disparity processing. The results imply that the main mechanisms subserving stereoscopic depth discrimination are vertically elongated for vertical-bar Gabors and encounter special difficulties integrating horizontal disparity information. Disparity discrimination sensitivity for very small targets was also much greater than predicted by the single-mechanism fit, implying the presence of a second, independent mechanism with a very small summation field, which may underlie the fine stereoscopic processing system.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vision Research - Volume 46, Issue 17, September 2006, Pages 2691–2702
نویسندگان
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