The involvement of cortical areas in the generation of eye movements enables the investigation of these processes with the event related potential technique. Applying the two stimulus paradigm several studies found a negative potential shift with a maximum at central leads preceding the peripheral cue. This negative component is called presaccadic negativity (PSN). The PSN is normally larger during anti- as compared to prosaccade tasks. The participation of different cortical structures should produce topographical differences between tasks, whereas metabolic changes would only produce amplitude differences over similar cortical structures. The aims of this study was a) to increase the spatial resolution of the PSN records in order to compare the PSN topographies during the pro- and antitasks, and b) to improve the artefact correction with the MSEC method in combination with single trial examination in order to analyse the ERP during the interval after onset of the peripheral cue.

28 participants were tested in this study. Pro- and antisaccades were elicited within the two-stimulus paradigm: a central fixation point was followed 3.5 s later by a peripheral cue, appearing randomly ±4° to the left or right. Fixation point offset preceded cue onset by 0.2 s (gap condition). Four blocks of 40 trials were provided for each task. The EEG was recorded with a DC amplifier using a 32-channel electrode montage. The data sets from 22 participants were used for further analysis.

Analyses of the scalp potential and Laplacian topography of the presaccadic negativity (PSN), the presaccadic negative spike (PNS), and the postsaccadic negativity (PostSN) during the prosaccade and antisaccade tasks were accomplished in the present study. Saccadic reaction times were significantly slower (about 80 ms) during the antitask than during the protask. Statistical analyses on a subset of 12 electrodes revealed central maxima of the PSN, PNS, and the PostSN, that were larger during anti- as compared to the protask. The anterior amplitude augmentations were consistent with the assumption of topography change for the PSN and PNS. Our results suggest that the cortical generators of the PSN and PNS are located more anteriorly during antitask than during the protask. The PNS may reflect a brisk increase of the PSN after presentation of the cue.