The importance of functional hemispheric asymmetry in the assessment of cognitive evoked potentials and reaction time

Abstract

The aim of this study was to determine whether there is a correlation of latency and amplitude of P300 cognitive potential and the degree of lateralization of brain hemispheres. The study included 60 subjects whose age was between 45 and 56 years. Bioelectric brain activity was recorded using argentum chloride (AgCl) electrodes that were placed at central line of the scalp (over Fz and Cz regions) according to the international 10-20 standard. P300 was generated using 'oddball' paradigm with randomized stimuli: A frequent 1000 Hz tone with an occurrence of 80 % and a 2000 Hz tone (target) with a 20 % occurrence. The measurement is done with the right hand (first recording) and left hand (second recording). All subjects in this study were tested for usage lateralization and showed that they are right-handed. Based on the results of gestural lateralization subjects are divided in three groups. In the group with high degree of lateralization latencies of P300 were significantly lower when dominant hand was used in comparison to non-dominant hand, on Fz electrode (t = 4,162, p0.05) for latencies and amplitudes of P300 between dominant and non-dominant hand for the group of subjects with weak and average degree of lateralization. In both subject groups, significantly faster RT was measured when dominant hand was used. The P300 cognitive potential and reaction time can contribute to the study of indicators of the functional hemispheric asymmetry of the brain.

Keywords

• P300
• ERP
• Reaction time
• functional asymmetry