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Primary Visual Cortex as a Saliency Map: A Parameter-Free Prediction and Its Test by Behavioral Data.

Zhaoping L, Zhe L - PLoS Comput. Biol. (2015)

Bottom Line: This hypothesis has so far provided only qualitative predictions and their confirmations.A requirement for this successful prediction is a data-motivated assumption that V1 lacks neurons tuned simultaneously to color, orientation, and motion direction of visual inputs.Since evidence suggests that extrastriate cortices do have such neurons, we discuss the possibility that the extrastriate cortices play no role in guiding exogenous attention so that they can be devoted to other functions like visual decoding and endogenous attention.

View Article: PubMed Central - PubMed

Affiliation: University College London, London, United Kingdom.

ABSTRACT
It has been hypothesized that neural activities in the primary visual cortex (V1) represent a saliency map of the visual field to exogenously guide attention. This hypothesis has so far provided only qualitative predictions and their confirmations. We report this hypothesis' first quantitative prediction, derived without free parameters, and its confirmation by human behavioral data. The hypothesis provides a direct link between V1 neural responses to a visual location and the saliency of that location to guide attention exogenously. In a visual input containing many bars, one of them saliently different from all the other bars which are identical to each other, saliency at the singleton's location can be measured by the shortness of the reaction time in a visual search for singletons. The hypothesis predicts quantitatively the whole distribution of the reaction times to find a singleton unique in color, orientation, and motion direction from the reaction times to find other types of singletons. The prediction matches human reaction time data. A requirement for this successful prediction is a data-motivated assumption that V1 lacks neurons tuned simultaneously to color, orientation, and motion direction of visual inputs. Since evidence suggests that extrastriate cortices do have such neurons, we discuss the possibility that the extrastriate cortices play no role in guiding exogenous attention so that they can be devoted to other functions like visual decoding and endogenous attention.

No MeSH data available.


The fraction of the tests of each race equality that falsify the equality for each observer.Each observer is color coded by: red, white, green, blue, cyan, magenta, yellow, or black (red for our example observer SA). Different tests of an equality use different sets of parameters in the testing method to include all possible combinations of the parameter values. Each race equality is tested on six or eight observers as indicated. Results for REi for i = 2–4 is placed above that of its corollary equality REi+4 for easy of comparison.
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pcbi.1004375.g009: The fraction of the tests of each race equality that falsify the equality for each observer.Each observer is color coded by: red, white, green, blue, cyan, magenta, yellow, or black (red for our example observer SA). Different tests of an equality use different sets of parameters in the testing method to include all possible combinations of the parameter values. Each race equality is tested on six or eight observers as indicated. Results for REi for i = 2–4 is placed above that of its corollary equality REi+4 for easy of comparison.

Mentions: Fig 9 plots the fraction of all the (80 or 320) tests in which an equality is found broken in each observer and each race equality. In more than half of the cases, this fraction is either larger than 90% or smaller than 10%, indicating that the variations in the parameters of our method do not substantially affect whether the race equality holds. For some observers in some race equalities, e.g., observers marked by white, blue, and magenta color for RE2, a race equality is consistently broken using one metric and consistently maintained using another metric, (almost) regardless of the variations of the other parameters for the tests. For our non-spurious race equality, no test parameter value of any type consistently break the equality in any observer regardless of the other parameters.


Primary Visual Cortex as a Saliency Map: A Parameter-Free Prediction and Its Test by Behavioral Data.

Zhaoping L, Zhe L - PLoS Comput. Biol. (2015)

The fraction of the tests of each race equality that falsify the equality for each observer.Each observer is color coded by: red, white, green, blue, cyan, magenta, yellow, or black (red for our example observer SA). Different tests of an equality use different sets of parameters in the testing method to include all possible combinations of the parameter values. Each race equality is tested on six or eight observers as indicated. Results for REi for i = 2–4 is placed above that of its corollary equality REi+4 for easy of comparison.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595278&req=5

pcbi.1004375.g009: The fraction of the tests of each race equality that falsify the equality for each observer.Each observer is color coded by: red, white, green, blue, cyan, magenta, yellow, or black (red for our example observer SA). Different tests of an equality use different sets of parameters in the testing method to include all possible combinations of the parameter values. Each race equality is tested on six or eight observers as indicated. Results for REi for i = 2–4 is placed above that of its corollary equality REi+4 for easy of comparison.
Mentions: Fig 9 plots the fraction of all the (80 or 320) tests in which an equality is found broken in each observer and each race equality. In more than half of the cases, this fraction is either larger than 90% or smaller than 10%, indicating that the variations in the parameters of our method do not substantially affect whether the race equality holds. For some observers in some race equalities, e.g., observers marked by white, blue, and magenta color for RE2, a race equality is consistently broken using one metric and consistently maintained using another metric, (almost) regardless of the variations of the other parameters for the tests. For our non-spurious race equality, no test parameter value of any type consistently break the equality in any observer regardless of the other parameters.

Bottom Line: This hypothesis has so far provided only qualitative predictions and their confirmations.A requirement for this successful prediction is a data-motivated assumption that V1 lacks neurons tuned simultaneously to color, orientation, and motion direction of visual inputs.Since evidence suggests that extrastriate cortices do have such neurons, we discuss the possibility that the extrastriate cortices play no role in guiding exogenous attention so that they can be devoted to other functions like visual decoding and endogenous attention.

View Article: PubMed Central - PubMed

Affiliation: University College London, London, United Kingdom.

ABSTRACT
It has been hypothesized that neural activities in the primary visual cortex (V1) represent a saliency map of the visual field to exogenously guide attention. This hypothesis has so far provided only qualitative predictions and their confirmations. We report this hypothesis' first quantitative prediction, derived without free parameters, and its confirmation by human behavioral data. The hypothesis provides a direct link between V1 neural responses to a visual location and the saliency of that location to guide attention exogenously. In a visual input containing many bars, one of them saliently different from all the other bars which are identical to each other, saliency at the singleton's location can be measured by the shortness of the reaction time in a visual search for singletons. The hypothesis predicts quantitatively the whole distribution of the reaction times to find a singleton unique in color, orientation, and motion direction from the reaction times to find other types of singletons. The prediction matches human reaction time data. A requirement for this successful prediction is a data-motivated assumption that V1 lacks neurons tuned simultaneously to color, orientation, and motion direction of visual inputs. Since evidence suggests that extrastriate cortices do have such neurons, we discuss the possibility that the extrastriate cortices play no role in guiding exogenous attention so that they can be devoted to other functions like visual decoding and endogenous attention.

No MeSH data available.