Indices of Coherence of EEG Rhythms in the Course of Cognitive Activity as Markers of Creative Thinking: Gender Specificity

Abstract

According to the results of psychological testing, persons aged 18 to 21 years were divided into four groups, women and men with low and high productivity of divergent (creative, nonroutine) thinking (n = = 18 to 23). Results of EEG recording (19 leads) were used for calculation of the coherence coefficients for oscillations of the delta, theta, alpha1, alpha2, alpha3, beta, and gamma frequencies in lead pairs and estimation of integral indices of coherence within the anterior and posterior cortical regions and between these zones (interaction coefficients, IC1-IC3, respectively). EEG was recorded in the resting state and in the course of resolving convergent- and divergent-type cognitive test tasks. It was found that, during the performance of tests of both types, men with a higher productivity of divergent thinking demonstrated significantly higher values of IC1 (that characterizes the coherence in associative linkages within the anterior cortex) for oscillations of all EEG frequency ranges compared with the respective estimates for “low-creative” men. Similar increments were typical of the IC2 values for low- and mid- frequency EEG rhythms (delta, theta, and alpha). At the same time, values of the “interregional” IC3 for theta, beta, and gamma activity in “high-creativity” men were significantly lower. In women of both groups (low and high creativity), such specificity of the IC1-IC3 patterns was practically not observed, i.e., the respective aspect demonstrated clear gender specificity. The sex of the subjects and type of the performed cognitive tests could not be considered factors significantly affecting the calculated absolute IC values. The observed specificities of integral coherence indices are probably associated with different strategies of the performance of cognitive tasks in men and women. Our findings allow us to believe that the above interrelations between integrated coherence indices can be used as EEG markers of high productivity of divergent thinking in men. The more flexible strategies of thinking in women are probably related to more variable neurophysiological cortical mechanisms (compared with those in men), and this type of organization is not clearly reflected in the pattern of intracortical interactions estimated by coherence indices.