The task complexity and Extraversion: an ERP study

Trying to prove the validity of Eysenck’s theories for the biological basis of personality many data for the differences between extraverts and introverts were collected. It was obtained, that the ERP differences between extraverts and introverts depend on the intensity and frequency of stimulation, but the papers concerning task difficulty dependence are very limited. The purpose of this work was to investigate how the task complexity affects ERP differences between extraverts and introverts. For testing the extraversion we used Eysenck Personality Questionary (EPQ). We recorded EEG under four equal audio series of pseudo-randomized low and high tones. We changed the level of task complexity by different instructions: 1 - passive listening; 2 – answering with the right index finger to the low tone and the left index finger to the high tone; 3 – counting the low tones; 4 – answering with the right index finger to low tones; We averaged stimulus locked ERP across each series and tones for extraverts and introverts separately. It was evident that the ERP differences between extraverts and introverts depend on the task complexity. We found P2, N2 and P3 latency differences and N1, P2, N2 and P3 amplitude differences. As whole extraverts showed larger N2 amplitudes and shorter N2 latencies. The differences were more pronounced in the task supposed less complexity and decreased with the increase of task complexity

EEG Fractal Dimension Measurement before and after Human Auditory Stimulation

The aim of this work is to investigate the change of fractal dimension Df with the help of Higuchi Fractal Dimension measure (HFD) in Event-Related Potentials (ERP) of human EEG time series, obtained as a result of oddball paradigm usage and auditory stimulation with instruction for passive listening and counting tasks, depending on gender, personality type and task condition. In our study 77 healthy volunteers have been participated and 38 of them have been selected after a personality classification with Eysenck’s personality questionnaire (EPQ).The achieved results showed specific functional meaning of ERP HFD change depending on the individual personality type and gender