Differences in the ability to process a visuo-spatial task are reflected in event-related slow cortical potentials of human subjects

Recent positron emission tomography (PET) and electroencephalographic (EEG) studies suggest that higher ability in a cognitive task is associated with a more efficient neuronal processing of this task. However, the validity a nd generalizability of these studies is limited for several reasons. We inv estigated 20 male and 18 female human subjects with good vs. poor spatial a bility performing a visuo-spatial task (cube test). Processing-related slow event-related potentials were recorded via 22 electrodes, evenly distribut ed over the scalp. Significant differences between good and poor performers were found in both sexes: poor subjects showed higher activity in the pari etal region, and their topography was more extended into fronto-central reg ions. Since the amount and topography of brain activity may vary considerab ly depending on subjects' ability, we conclude that careful (experimental) control of task-specific ability of subjects is mandatory for cognitive neu roscience studies. (C) 1999 Elsevier Science Ireland Ltd. All rights reserv ed.