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Neural Models of Bayesian Belief Propagation Rajesh ... - Washington

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262 11 <strong>Neural</strong> <strong>Models</strong> <strong>of</strong> <strong>Bayesian</strong> <strong>Belief</strong> <strong>Propagation</strong> <strong>Rajesh</strong> P. N. Rao<br />

A<br />

Up<br />

Lt 1 2 3 4 5 Rt<br />

Dn<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

Lt<br />

1 2 3 4 5<br />

Spatial Positions<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

Rt<br />

1 2 3 4 5<br />

B<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

1 2 3 4 5<br />

0.8<br />

Up Dn<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

1 2 3 4 5<br />

Figure 11.8 Input Image Configuration and Conditional Probabilities used in the Attention<br />

Experiments. (A) Example image locations (labeled 1-5 and Up, Dn, Lt, and Rt<br />

for up, down, left, and right) relevant to the experiments discussed in the paper. (B)<br />

Each bar plot shows P (Ci|L, F ) for a fixed value <strong>of</strong> L (= Lt, Rt, Up, or Dn) and for an<br />

arbitrary fixed value <strong>of</strong> F . Each bar represents the probability for the feature-location<br />

combination Ci encoding one <strong>of</strong> the locations 1-5.<br />

Response<br />

0.5<br />

0.3<br />

Model V4 Neuron<br />

0.0<br />

−90 −60 −30 0 30 60 90<br />

Orientation (in degrees)<br />

A B<br />

Figure 11.9 Multiplicative Modulation due to Attention. (A) Orientation tuning curve<br />

<strong>of</strong> a feature coding model neuron with a preferred stimulus orientation <strong>of</strong> 0 degrees<br />

with (filled squares) and without (unfilled circles) attention (from [31]). (B) Orientation<br />

tuning curves <strong>of</strong> a V4 neuron with (filled squares) and without attention (unfilled<br />

circles) (from [23]).

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