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Alexandre Reynaud, Yong Tang, Yifeng Zhou, Robert Hess; A unified framework and normative dataset for second-order sensitivity using the quick Contrast Sensitivity Function (qCSF) . Journal of Vision 2014;14(10):1428. doi: 10.1167/14.10.1428.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction: While the contrast sensitivity approach has been successful in quantifying striate function, there is a need to develop comparable ways of evaluating extra-striate function in humans. Neurophysiologically, the extra-striate cortex differs from the striate cortex in a number of important ways. Second-order modulated stimuli are thought to be processed by the visual system in two serial stages; the carrier is processed by the localized, spatially bandpass neurons in V1 and in a second stage the rectified V1 output is integrated in extra-striate cortex. Here, our purpose is to establish normative data on the sensitivity of extra-striate human cortical function. Methods: We optimally designed second-order stimuli contrast-, orientation- or motion-modulated in order to reflect extra-striate function. We use a common novel methodology, the quick contrast sensitivity function (qCSF) method, recently developed for the rapid measurement of visual contrast sensitivity across a range of spatial frequencies relevant to striate function (Lesmes et al., 2010). This method is a Bayesian adaptive procedure that estimates multiple parameters of the sensitivity function and concurrently estimates thresholds across the full spatial-frequency range. It was originally built to determine the first-order contrast sensitivity function, but here we use it for determining both first and second-order functions. Results: We first show that the qCSF methodology can be well adapted to different kinds of first- and second-order measurements. We provide a normative dataset (102 eyes) for first- and second-order sensitivity and we show that the sensitivity to all these stimuli is equal in the two eyes. Conclusions: Our results confirm some strong differences between first- and second-order processing, in accordance with the classical filter-rectify-filter model. They suggest a unique contrast detection mechanism but different second-order ones.
Meeting abstract presented at VSS 2014
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