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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 predicted and observed P(RTCMO) from the non-spurious equality and the three spurious ones, listed in Eqs (31)–(34), are plotted in A, B, C, and D, respectively.These four equalities share a similar complexity and are also denoted as RE1, RE6, RE7, and RE8, respectively, in Table 1.
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pcbi.1004375.g008: The predicted and observed P(RTCMO) from the non-spurious equality and the three spurious ones, listed in Eqs (31)–(34), are plotted in A, B, C, and D, respectively.These four equalities share a similar complexity and are also denoted as RE1, RE6, RE7, and RE8, respectively, in Table 1.

Mentions: Each of Eqs (31)–(34) (one non-spurious) can predict the distribution of RTCMO using the same set of six types of reaction times RTα for α = C, M, O, CM, CO, MO. Fig 8B 8C 8D show that, in our example observer SA, the first two but not the last one of the spurious, corollary, equalities are falsified, mirroring the falsification of the original spurious equalities in Fig 5A 5B 5C. Hence, complexity in a race equality is insufficient to prevent its falsification.


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 predicted and observed P(RTCMO) from the non-spurious equality and the three spurious ones, listed in Eqs (31)–(34), are plotted in A, B, C, and D, respectively.These four equalities share a similar complexity and are also denoted as RE1, RE6, RE7, and RE8, respectively, in Table 1.
© Copyright Policy
Related In: Results  -  Collection

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

pcbi.1004375.g008: The predicted and observed P(RTCMO) from the non-spurious equality and the three spurious ones, listed in Eqs (31)–(34), are plotted in A, B, C, and D, respectively.These four equalities share a similar complexity and are also denoted as RE1, RE6, RE7, and RE8, respectively, in Table 1.
Mentions: Each of Eqs (31)–(34) (one non-spurious) can predict the distribution of RTCMO using the same set of six types of reaction times RTα for α = C, M, O, CM, CO, MO. Fig 8B 8C 8D show that, in our example observer SA, the first two but not the last one of the spurious, corollary, equalities are falsified, mirroring the falsification of the original spurious equalities in Fig 5A 5B 5C. Hence, complexity in a race equality is insufficient to prevent its falsification.

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.