[Differences in human evoked visual potentials depending on the capacity for the self-regulation of their parameters by feedback].

The individual characteristics of the VEP spatio-temporal patterns were studied depending on a capability of a subject for VEP biofeedback conditioning. Thirty two healthy adult volunteers had to modify their N100-P200 VEP component (Cz derivation) within a selected time window in order to increase the number of trials in which the amplitude of the segment from the beginning of the sample to the positive peak exceeded a definite threshold. In addition to traditional visual assessment of topographical maps, the statistical analysis of multichannel VEPs and component analysis for Cz, O1, and O2 were carried out for each discrete time sample. The differences were observed in the spatio-temporal VEP patterns for successful and unsuccessful performance. In the background sessions, the central and occipital P200 components were much the same in the subjects which succeeded in task performance, whereas the central component was noticeably higher than the occipital one in the subjects who were unsuccessful in biofeedback control. During successful performance, there was a reduction of the occipital P200. Thus, the relationships of VEP components in the central and occipital derivations can predict successful biofeedback conditioning and may reflect the prevalence of verbal and non-verbal thinking.