Source localization algorithms to find attention and memory circuits in the brain

Brain is a complex organ and many attempts have been done to know its functions. Studying attention and memory circuits can help to achieve much information about the brain. P300 is related to attention and memory operations, so its investigation will lead to better understanding of these mechanisms. In this study, EEG signals of thirty healthy subjects are analyzed. Each subject participates in three-segment experiment including start, penalty and last segments. Each segment contains the same number of visual and auditory tests including warning, attention, response and feedback phases. Data analysis is done by using conventional averaging techniques and P300 source localization is carried out with two localization algorithms including low-resolution and high-resolution algorithms. Using realistic head model to improve the accuracy of localization, our results demonstrate that the P300 component arises from a wide cerebral cortex network and localizing a definite generating cortical zone is impossible. This study shows that a combination of high-resolution and low-resolution algorithms can be a useful tool for physiologists to find the neural sources of primary circuits in the brain.