EVENT-RELATED POTENTIALS DURING OBJECT RECOGNITION TASKS

In our previous studies, we have demonstrated an ERP correlate of visu al memory with a modified delayed matching-to-sample paradigm using a series of nonsense line drawings or faces as stimuli. In this experime nt, we employed pictures of objects to determine whether the ERP can r eflect the object recognition process and whether visual stimuli with a verbal label would result in a different topographic distribution fr om past topography obtained with visual stimuli without a verbal label . The results of this study suggest that the amplitude of the ERP comp onent (c247) to repeated (primed) pictures of common objects was signi ficantly decreased as compared to the unrepeated (unprimed) pictures; the latency for the peak of c247 was decreased for the repeated compar ed to the unrepeated, and the response time was also significantly sho rter to the repeated picture stimuli than to the unrepeated; the topog raphical distribution of c247 was mainly located in the occipitotempor al areas of the brain. However, the source energy density map showed t hat the topographic involvement of the brain regions to the c247 was d ifferent in the matching and nonmatching trials.