State-Dependent TMS of the Right Lateral Occipital Complex Does not Disrupt Object Detection and Categorization

Abstract

Object detection and categorization are essential to object recognition. Previous studies suggested that the lateral occipital complex (LOC) plays a key role in various steps of object representation. However, it remains unclear whether the LOC contributes to object detection or object categorization causally. To investigate these issues, two experiments were conducted using an object priming paradigm. The results of the first experiment demonstrated the validity of an object priming paradigm for dissociating object detection and categorization within the same task in both accuracy and reaction time. Next, in the second experiment, state-dependent transcranial magnetic stimulation (TMS) was applied to the right LOC (rLOC) within a similar paradigm. The results showed a dissociation between the object detection and categorization in reaction time as well. A direct causal relationship between the rLOC and the representation of object detection or object categorization, however, was not found. Together, these findings suggest a dissociation between perceptual detection and categorization of objects within the same task. This indicates an earlier detection of objects than the categorization of them. TMS over the rLOC neither alters object detection nor categorization in the current priming task and used setup.