[Dipole sources localization of late components of event-related potentials during effective and ineffective visual...

The question concerning the mechanisms for choice of relevant information is disputable. One point of view is that competition of entrance information for selective attention may be parallel if a target has a distinguishing character. The other one suggests that a search for relevant information is always successive but takes different rates. We examined the relevancy of these approaches by means of comparison of cortical areas involved in a decision-making process in the visual search tasks realized with the different effectiveness. The method of the ERP dipole sources localization was used. The ERPs to images in visual search tasks with different "difficulty" were recorded. Distribution of cortical sources of the ERP late components was analyzed. A task complication resulted in an activity focus displacement from the occipital to frontal cortical areas. The results suggest different mechanisms for effective and ineffective search and testify that the processes of the relevant information selection may be simultaneous and successive.