Abstract
Target objects required for goal-directed behavior are typically embedded within multiple irrelevant objects. Recent neuroimaging studies reported mixed results on the extent to which distributed responses to objects in the lateral occipital complex (LOC) are independent of their task-irrelevant surroundings. To examine the effect of task-irrelevant clutter on the responses to objects we used functional magnetic resonance imaging (fMRI) and manipulated the type of clutter while subjects identified target objects. Target objects were presented either in isolation, in the presence of a homogeneous clutter, or in the presence of a heterogeneous clutter. We found that a heterogeneous but not homogeneous clutter interfered with decoding of target objects in the object area. Moreover, the response pattern to an isolated target object was more similar to its pattern when presented with a homogeneous clutter than when presented with a heterogeneous clutter. Interestingly, representations of preferred target objects in category-selective areas were not affected by the presence of the clutter or the type of the clutter. These findings suggest that attended preferred objects may be better secluded from irrelevant non-preferred objects within their category selective cortex. Our findings clearly show that the representation of target objects is not independent of their surrounding in LOC and that irrelevant clutter information is also represented. These findings further suggest that the variation among the non-target objects, rather than the number of non-target objects per-se, modulates the representation of target objects in LOC.
Meeting abstract presented at VSS 2013