Abstract
Integrating discrete features into coherent object representation is an essential ability of the human brain. However, the basic relationship between the binding processing and the object representation is still not clarified — Are they the same or different processes? Are they supported by the same or different neural mechanisms? We combined Electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) approaches, attempting to dissociate the binding processing and the object representation by modulating the support ratio (SR) of Kanizsa-type illusory counters (IC, which is a classical example of visual feature binding). The hypothesis is that: as the SR increases, less binding (interpolation of the discrete edges of an IC) is needed while the perception of an object (IC) becomes stronger. Such dissociated results were observed in the occipital EEG results. The induced gamma activity occurring at about 100∼150 ms decreased with SR, while the ERP component N1 occurring at about 170 ms increased with SR. The fMRI results further showed that the lateral occipital cortex (LOC) activation increased with SR. We thus show dissociable binding and object processes, which are associated with the induced gamma activity and the N1 respectively. This finding also provides the evidence for different roles of the induced and evoked activities in cognitive functions. The fMRI results further confirm the role of the LOC in object representation with a parametric design. A tentative indication of the present results may be that, the binding processing and the object representation occur at the same brain regions but involve different neurons.
National Nature Science Foundation of China (30370478).