The Neural Basis of Visual Search in Scene Context.

Humans are highly efficient in finding objects in their structured, daily-life environments. Behavioral studies have demonstrated that this efficiency is supported by expectations derived from scene context. Here, I review neuroimaging studies that have started to reveal the neural basis of contextual influences on visual search for objects. These studies point to a central role for the object-selective visual cortex (OSC) in mediating multiple types of contextual influences. Supporting the attentional guidance by scene context, activity patterns in the OSC reflect global contextual expectations about target location and represent local nontarget objects that are contextually associated with the target. Preparatory activity patterns in the OSC also incorporate contextual expectations about target appearance (e.g., object size) during the preparation phase of visual search. In addition to supporting attentional guidance, object representations in the OSC are directly facilitated by scene context, and this facilitation is causally linked to object-identification performance. Finally, activity patterns in the anterior OSC integrate representations of distractor objects that are positioned according to familiar configurations, thereby reducing scene complexity. Together, these studies show how attention and expectation interactively drive preparatory activity and jointly modulate the visual processing of potential targets, providing a neural basis for the efficiency of search in scenes.