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Abstract:
Abstract: Different features of objects in the visual field
(e.g., shape, color, motion, location) are processed in different
areas and pathways in the visual cortex. Our model shows how the
selection of one feature of an object (e.g., its shape or color)
results in an attentional enhancement of activity for all neurons
that represent the features of the object in all areas of the
visual cortex. In our model, feedforward activation interacts with
feedback activation in the retinotopic areas of the visual cortex.
The feedforward activation results from the stimulus (bottom-up),
and the feedback activation results from the selected object
feature (top-down). The interaction occurs in local microcircuits,
which produce gain and gating of activation by means of
disinhibition. This selectively enhances the activation of only
those neurons that are activated by the selected object. It also
retrieves the location of the selected object in the retinotopic
areas. As a result, (spatial) attention can be directed to the
object as a whole, which results in an enhanced activation of the
neurons responsive to the other features of the selected object. In
this way, the activation of neurons responsive to the selected
object are enhanced in all areas of the visual cortex, which
integrates the features of the object and selects the object from
other objects in the visual field.
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