© J. Petrek PICTORIAL COGNITIVE TASK RESOLUTION AND DYNAMICS OF EVENT-RELATED POTENTIALS

Aims: To judge whether and how the character of the visual stimulus and type of cognitive task aff ects brain event-related potentials (ERPs). Methods: ERPs to three types of visual stimuli (white blank oval on a dark background, unfolded cube and net of sixteen small squares) were recorded from nine scalp sites and saved on a computer. Special software was used for off-line analysis of the ERPs. Results: The presentation of each of the three visual stimuli used was followed by ERPs consisting of two negative (N160, N340) and one positive (P220) components. The character of the stimulus did not aff ect the latency of ERPs components. However, the type of visual stimuli aff ected the amplitude. The most conspicuous changes were shown by the N340 ERPs component. Its average amplitude in comparison with reference amplitude was always signifi-cantly higher during the fi rst cognitive task (“Choose the cube that can be folded up from the unfolded cube!”) and signifi cantly lower than reference amplitude during the second cognitive task (“Complete the missing part of a fi gure with the appropriate item!”). It was also shown that subjective personality traits such as nervousness, spontaneous aggressivity and emotional lability had an infl uence on the recovery phase of the experiment aff ecting the average amplitude of N340 Conclusion: The results revealed that the cognitive processes underlying successful resolution of two pictorial cognitive tasks aff ected diff erently the activity of systems giving rise to visual ERPs