کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4035629 1263538 2007 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Differential roles of contrast polarity reveal two streams of second-order visual processing
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی سیستم های حسی
پیش نمایش صفحه اول مقاله
Differential roles of contrast polarity reveal two streams of second-order visual processing
چکیده انگلیسی

Humans can easily segregate texture regions based on differences in contrast, orientation, and contrast polarity. It has been suggested that these abilities can be inclusively modeled by 2nd-order visual mechanisms that detect changes in the half-wave rectified outputs of orientation-selective filters. Using a subthreshold-summation paradigm, however, we show that modulations of contrast polarity are detected by mechanisms that pool signals of different orientations while modulations of orientation are detected by mechanisms that pool signals of different contrast polarities. The results support the existence of two streams of 2nd-order processing, one that receives the full-wave rectified inputs from oriented filters, the other separate half-wave rectified outputs from on-center and off-center filters pooled across all orientations. The two-stream model is shown to predict the perceptual effects of changes to the skewness statistics of natural-image textures, and to solve a contradiction among previous data concerning the detection of contrast modulation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vision Research - Volume 47, Issue 15, July 2007, Pages 2047–2054
نویسندگان
, ,