Thomas Trappenberg, Edmund Rolls, Simon Stringer
Inferior temporal cortex (IT) neurons have large receptive ﬁelds when a single effective object stimulus is shown against a blank background, but have much smaller receptive ﬁelds when the object is placed in a natural scene. Thus, translation invariant object recognition is reduced in natural scenes, and this may help object selection. We describe a model which accounts for this by competition within an attractor in which the neurons are tuned to different objects in the scene, and the fovea has a higher cortical magniﬁcation factor than the peripheral visual ﬁeld. Further- more, we show that top-down object bias can increase the receptive ﬁeld size, facilitating object search in complex visual scenes, and providing a model of object-based attention. The model leads to the prediction that introduction of a second object into a scene with blank background will reduce the receptive ﬁeld size to values that depend on the closeness of the second object to the target stimulus. We suggest that mechanisms of this type enable the output of IT to be primarily about one object, so that the areas that receive from IT can select the object as a potential target for action.