Gender-Dependent Frequency-Spatial Organization of the Brain Cortex Activity during Convergent and Divergent Thinking: II. Analysis of the EEG Coherence

Abstract

Gender dimorphism is inherent in various cognitive activities, including convergent (CTh) and divergent (DTh) thinking [1,2]; however, features of the functional hemispheric lateralization characteristic of men and women [3][4][5] during solving mathematical (CTh) or creative (DTh) tasks remain unstudied. Considering that gender differences in brain activity have been observed even in the case of equal efficiencies of cognitive performance [5,6], analysis of the frequencyspatial EEG organization during CTh and DTh may be useful for revealing features of the functional interhemispheric interaction in men and women. Guilford [7] proposed the model of DTh for describing the creative type of thinking, implying many solutions of a problem, each of which can be correct, in contrast to CTh, with a single correct solution. Investigation of inter-and intrahemispheric interactions by mapping coherent connections between different cortical areas is of special interest with such models because they offer a possibility of direct observation of convergence or divergence of neuronal connections depending on the test conditions.It is well known that, in general, men perform arithmetic IQ subtests better than women [1,8,9]. However, although a number of articles are concerned with the neurophysiological mechanisms of mathematical operations [10-13], their gender-related features are scarcely considered in these works. At the same time, high specialization of the brain hemispheres during the performance of verbal and spatial tasks has been found in men [4,5]. This fact suggests that convergent processes are more pronounced in men and, consequently, success in solving of mathematical (convergent) tasks by men and women is also associated with genderrelated features of interhemispheric interactions.Analysis of the gender-related features of interhemispheric interactions during DTh (creative thinking) provokes still greater interest. It has been shown that interhemispheric asymmetry is weaker in highly creative than in low-creative subjects [14][15][16][17][18]. At the same time, a closer interhemispheric interaction has been observed in women compared to men [19][20][21]. Consequently, gender differences in hemispheric interaction may be expected for DTh. Indeed, investigation of the cortical mechanisms of creativity has established that the performance of a verbal task in men is associated with an increase in interhemispheric coherence (Coh) between the right posterior and left frontal cortical areas, whereas a stronger connection between the left posterior and right frontal and mediotemporal areas has been observed in women [22]. Analysis of the EEG spatial organization in two α bands has shown that, during composing a story, intrahemispheric Coh in the α 1 rhythm in the left hemisphere increases only in women. Also, Coh increases between the centroparietal sites in Abstract -The gender dependence of inter-and intrahemispheric interactions of neuronal assemblies during convergent (CTh) and divergent (DTh) thinking was studied on ...