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  Top-down control over visual-contrast sensitivity

de la Rosa, S., Schneider, B., & Gordon, M. (2007). Top-down control over visual-contrast sensitivity. Poster presented at 30th European Conference on Visual Perception (ECVP 2007), Arezzo, Italy.

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de la Rosa, S1, Author              
Schneider, B, Author
Gordon, M, Author
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1External Organizations, ou_persistent22              

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 Abstract: The visual system is able to adjust its contrast sensitivity to the ambient contrast level. Others have shown that this adjustment is driven by stimulus parameters in a bottom - up fashion and higher order processes by means of attention. We present evidence that contrast sensitivity is under true top - down control. We paired an absolute identification paradigm with a cueing paradigm to measure identification accuracy for four low-contrast stimuli that were intermixed with an occasional high-contrast stimulus. Foreknowledge of the presentation of the high-contrast stimulus was manipulated by presenting valid and invalid cues. In experiment 1 we found that identification and discriminability of low-contrast stimuli was impaired only when the occurrence of the high-contrast stimulus was unpredictable but not when it was predictable. Only a top - down gain-control mechanism whose functions were to maximize discriminability while protecting the system from overload was consistent with the results. Experiment 2 p rovided further support for the idea that an important function of gain control is to protect visual mechanisms from overload.

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 Dates: 2007-08
 Publication Status: Published in print
 Pages: -
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 Rev. Type: -
 Identifiers: BibTex Citekey: 5501
DOI: 10.1177/03010066070360S101
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Title: 30th European Conference on Visual Perception (ECVP 2007)
Place of Event: Arezzo, Italy
Start-/End Date: 2007-08-27 - 2007-08-31

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Title: Perception
Source Genre: Journal
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Publ. Info: London : Pion Ltd.
Pages: - Volume / Issue: 36 (ECVP Abstract Supplement) Sequence Number: - Start / End Page: 61 Identifier: ISSN: 0301-0066
CoNE: https://pure.mpg.de/cone/journals/resource/954925509369