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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 observed distributions of RTC, RTM, RTO, RTCM, RTCO, and RTMO for an observer are used to predict the distribution of RTCMO for the same observer (SA who was also in Figs 3 and 5) by the non-spurious race equality .The predicted and observed distributions of RTCMO are statistically indistinguishable from each other (p = 0.094). This figure has the same format as Fig 3.
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pcbi.1004375.g006: The observed distributions of RTC, RTM, RTO, RTCM, RTCO, and RTMO for an observer are used to predict the distribution of RTCMO for the same observer (SA who was also in Figs 3 and 5) by the non-spurious race equality .The predicted and observed distributions of RTCMO are statistically indistinguishable from each other (p = 0.094). This figure has the same format as Fig 3.

Mentions: Fig 6 shows that the observed distribution of RTCMO for our example observer SA is statistically indistinguishable from the non-spurious prediction using the other types of reaction times of this observer. Fig 7 shows that this agreement between the predicted and the observed RTCMO holds for all six naive adult observers.


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 observed distributions of RTC, RTM, RTO, RTCM, RTCO, and RTMO for an observer are used to predict the distribution of RTCMO for the same observer (SA who was also in Figs 3 and 5) by the non-spurious race equality .The predicted and observed distributions of RTCMO are statistically indistinguishable from each other (p = 0.094). This figure has the same format as Fig 3.
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Related In: Results  -  Collection

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

pcbi.1004375.g006: The observed distributions of RTC, RTM, RTO, RTCM, RTCO, and RTMO for an observer are used to predict the distribution of RTCMO for the same observer (SA who was also in Figs 3 and 5) by the non-spurious race equality .The predicted and observed distributions of RTCMO are statistically indistinguishable from each other (p = 0.094). This figure has the same format as Fig 3.
Mentions: Fig 6 shows that the observed distribution of RTCMO for our example observer SA is statistically indistinguishable from the non-spurious prediction using the other types of reaction times of this observer. Fig 7 shows that this agreement between the predicted and the observed RTCMO holds for all six naive adult observers.

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.