EEG CORRELATES OF DIFFERENT WAYS OF INFOR MATION-PROCESSING IN RESPONSE SELECTION

The lateralized readiness potential as a measure of response tendencie s has become a relevant method in experimental psychology within the l ast decade. This measure delivers information about response preparati on long before the overt response. Applying the method of measuring ev ent-related lateralizations (ERL) of the EEG to posterior sites, corre lates of processing of spatial information and of response selection h ave been found. The present study investigated the topographical distr ibution of asymmetries at the moment of response selection. Response s election was assumed to be reflected in a discrete peak of parietal as ymmetries. At this time point two distinct topographies were found tha t might reflect two different types of information processing. If resp onse selection was based on spatial information a parieto-occipital ma ximum was found. In contrast, if centrally presented symbolic stimuli were used for response selection, lateralizations were largest at cent ral (motor areas) and at parietal sites.