Comparative analysis of ethanol effects on the spatial organization of biopotentials under conditions of open and closed eyes during different types of thinking

Effects of low doses of ethanol on indices of spatial organization of cortical potentials (spatial synchronization, coherence, spectral power and information-power index) under the closed- and open-eyes conditions and during performance of divergent and convergent non-verbal and verbal tasks. Ethanol effect was shown to be more expressed under the open eyes-conditions as compared to that with the closed eyes. This finding may be associated with the greater effect of the stream of afferent information in the former case. Changes in topographical characteristics of the spatial synchronization of cortical potentials were more clearly localized and "specific" during divergent thinking as compared to the convergent type. Changes in the spectral power and information-power index testify to greater sensitivity to ethanol of divergent type of thinking as compared to convergent type. Psychological testing of stress resistance and impulsivity also showed a greater effect of ethanol on divergent thinking.     

Features of spatial organization of EEG and psychophysiological characteristics of the person with the divergent and convergent types of thinking

The psychophysiological indicators of spatial synchronization of biopotential at different types of mental processes in humans: non verbal-divergent, nonverbal-convergent, verbal-divergent and verbal-convergent were analyzed. The unequal relationship between the productivity of the implementation of tests on these types of thinking was revealed. The closest significant correlation exists between the productivity of the verbal-divergent and verbal-convergent thinking, and the lowest--between the productivity of nonverbally-divergent and nonverbally-convergent thinking. The differences in the topographical maps of the spatial synchronization of biopotential at different types of thinking was marked. They are most pronounced in the implementation of two non-verbal tasks, minimal--in two verbal tasks. Differences between different types of thinking are also manifested in the degree of coherence gain biopotential of the performance tests in comparison with the background (open eyes). Some physiological properties of the person that contribute to the divergent (creative) tests have a negative impact on the implementation of converged (tedious) tests. The findings are discussed in terms of differences in the level of general activation and participation of different ways of processing information (simultaneous and successiveness).     

The functional significance of α<Subscript>2</Subscript> frequency range for convergent and divergent verbal thinking

Mapping of the power and coherence of α₂ bioelectric potentials was used to detect a common effect of rhythm desynchronization in two types of convergent verbal thinking (generation of any words beginning with the given letter or simple associations) with more pronounced left-hemispheric activation predominantly in the temporo-parieto-occipital cortical area. In addition, there were specific functional changes in α₂ bioelectric potentials depending on the subjects’ sex and verbal creativity level, which was estimated by the capacity for divergent thinking (finding associations for triads of semantically remote words). The dynamics of the regional activation of the cortex depending on the verbal operation type was more characteristic of men compared to women and of creative persons compared to noncreative ones. In creative persons of both sexes, more original associations were accompanied by a decreased α₂-rhythm coherence. In noncreative women, interhemispheric interaction was, conversely, increased.     

Influence of individual psychological features on the EEG spatial organization in nonverbal divergent thinking

Effects of different psychophysiological characteristics on the speed of associative processes during the performance of a nonverbal-divergent (NVD) test (formation of the maximal possible number of visual images on the basis of two simple geometrical figures within 5 min) and on the spatial organization of bioelectric potentials (SOBP) were studied. Changes in the indices of spatial synchronization (SS) and spatial disorder (SD) of bioelectric potentials, which characterize, respectively, simple linear and more intricate nonlinear interrelations, were analyzed. A significant correlation was shown between 8 out of 35 psychophysiological indices analyzed (reflecting the emotional, motivational-behavioral, and cognitive styles; the total working capacity; and the autonomic tone) and the productivity index of the NVD test (fluency). Psychological features such as “stress susceptibility,” “disposition to nonstandard decisions and behavior,” “eccentricity,” “reflectivity,” and high “general and autonomic tone” facilitate activation (an increase in the SS and SD) in the frontotemporal areas of the right hemisphere, which is probably a neurophysiological correlate of success in performance of the test. Moreover, psychological features such as “field independence” and “autonomy” contribute to an increase in the activity of the occipital areas of the left hemisphere. In aggregate, the direction “frontal right-occipital left” areas becomes accentuated in the SOBP (the “creative axis”). According to our concept, this axis is of special importance in search operations and creative processes.     

Characteristics of the spatial organization of oscillations of brain bioelectric potentials in adolescents

Adolescence is characterized by an intense formation of interregional interaction of cortical areas. In this period, the activity of deep brain structures is significantly reorganizing and cortical-subcortical interaction is augmenting. Our objective was to assess the pattern of changes in the spatial structure of brain bioelectric potentials with age and characteristics of these structures in adolescents. For this purpose, studies of EEG were conducted in 230 subjects of both sexes aged 4 to 35 years. We quantified the interconsistent changes in correlations of oscillations of bioelectric potentials in 20-lead EEG, using the integrated index VOL. Age-related changes in the consistency of EEG correlations were analyzed both in the background state and during verbal activity (comprehension of texts in Russian and in English). Cognitive tasks were performed by subjects older than 8 years. It was discovered that spatial synchronization of EEG processes both in the background state and during cognitive tasks increased with age, but, after 20 years, the rate of changes decreases significantly. In adolescence (12–17 years), sex differences appear in the correlation of EEG processes between the left and right hemispheres in subjects performing verbal tasks. We observed saltatory changes in VOL indices in 12- to 14-year-old boys, whereas in girls of the same age, reorganization of systemic brain activity goes more gradually 1.5–2 years in advance.     

Motivation effect on power changes in the brain biopotentials in the figurative and verbal creativity tasks

Effect of extrinsic motivation stimulating the most original problem solving during verbal and figurative divergent thinking was studied by EEG mapping. The righthanded university students (27 males and 26 females) participated in the experiments. An instruction "to create the most original solution" as compared to condition with an instruction "to create any solution" induced an increase in the baseline power of the alpha 1 and alpha 2 rhythms most pronounced in the posterior cortex. Task-related desynchronization of the alpha rhythms was higher but the beta-2 synchronization was lower after the former than after the latter instruction. Differences in the asymmetry of the alpha 1 and alpha 2 rhythms in the parietal and temporal regions of hemispheres suggested the right hemisphere dominance in intrinsic alertness and evoked activation related to divergent thinking. The findings were common and gender-independent in both figurative and verbal tasks suggesting a generalized influence of extrinsic motivation on creative activity.     

Age-related characteristics of the formation of neurophysiological mechanisms of the phonemic, grammatical, and semantic linguistic levels

The structure of regional interactions of brain bioelectric potentials has been studied during performance by adults (n = 18) and children aged five to six (n = 15) and eight to nine years (n = 17) of three analytical verbal tasks: recognition of a given phoneme in the context of auditory presented words and recognition of grammatical and semantic mistakes in auditory presented sentences. According to the data of cross-correlation and coherent EEG analyses, adults and, to a lesser extent, children of both age groups showed a noticeable intensification of interhemispheric interaction during the performance of all three tasks, especially between temporal areas, with relatively minor changes in ipsilateral EEG relations. Children were shown to have elements of immaturity of neurophysiological mechanisms underlying various aspects of the language function, such as the analysis of the grammatical formation of a verbal utterance and the semantic content of a phrase. The results also suggest that the level of maturation of neurophysiological mechanisms underlying phonemic analysis is somewhat higher at these age stages than the level of maturity of central mechanisms responsible for the analysis of the semantic content and grammatical construction of a phrase. Quantitative comparison of the patterns of spatial interaction of cortical bioelectric potentials recorded during the performance of the tasks related to different linguistic levels showed a high degree of their statistical similarity for each of the age groups. The findings confirm the assumption that the distributive central maintenance of different linguistic levels is based on topologically close constellations of interacting cortical areas and on similar organization of their regional interactions.     

Strategy and results: Sex differences in electrographic correlates of verbal and figural creativity

Sex differences in electroencephalographic (EEG) correlates of creativity were studied using verbal and figural divergent tasks to be performed in accordance with the instructions to “give any solution” or “give an original solution.” The common effect was a greater activity of the right hemisphere, which did not depend on the sex, task type, or instructions for performance of the tasks. The α₂ and β₂ rhythms were the main EEG frequency correlates of creative thinking; the degree and sign of their reactivity depended on the aforementioned factors. Although the creative abilities in men and women were similar under test conditions, the EEG correlates of both figural and verbal tasks were sex-dependent. A high reactivity of the α₂ rhythm was more marked during verbal creative thinking in women; and that of the β₂ rhythm, during figural creative thinking in men. The instruction-related improvement of the critical selection of solutions was to a greater extent reflected by changes in the cortical activity, more pronounced in the frontal cortex in the women. Thus, the same creative productivity in men and women was mediated by different strategies of performance of both figural and verbal tasks, and the sex-related differences in these strategies remained even when the motivation for creativity was changed.     

The Relation between Gray Matter Morphology and Divergent Thinking in Adolescents and Young Adults

Adolescence and early adulthood are developmental time periods during which creative cognition is highly important for adapting to environmental changes. Divergent thinking, which refers to generating novel and useful solutions to open-ended problems, has often been used as a measure of creative cognition. The first goal of this structural neuroimaging study was to elucidate the relationship between gray matter morphology and performance in the verbal (AUT; alternative uses task) and visuo-spatial (CAT; creative ability test) domain of divergent thinking in adolescents and young adults. The second goal was to test if gray matter morphology is related to brain activity during AUT performance. Neural and behavioral data were combined from a cross-sectional study including 25 adolescents aged 15–17 and 20 young adults aged 25–30. Brain-behavior relationships were assessed without a priori location assumptions and within areas that were activated during an AUT-scanner task. Gray matter volume and cortical thickness were not significantly associated with verbal divergent thinking. However, visuo-spatial divergent thinking (CAT originality and fluency) was positively associated with cortical thickness of the right middle temporal gyrus and left brain areas including the superior frontal gyrus and various occipital, parietal, and temporal areas, independently of age. AUT brain activity was not associated with cortical thickness. The results support an important role of a widespread brain network involved in flexible visuo-spatial divergent thinking, providing evidence for a relation between cortical thickness and visuo-spatial divergent thinking in adolescents and young adults. However, studies including visuo-spatial divergent thinking tasks in the scanner are warranted.     

Differential influence of asynchrony in early and late chronotypes on convergent thinking

Eveningness preference (late chronotype) was previously associated with different personality dimensions and thinking styles that were linked to creativity, suggesting that evening-type individuals tend to be more creative than the morning-types. Nevertheless, empirical data on the association between chronotype and creative performance is scarce and inconclusive. Moreover, cognitive processes related to creative thinking are influenced by other factors such as sleep and the time of testing. Therefore, our aim was to examine convergent and divergent thinking abilities in late and early chronotypes, taking into consideration the influence of asynchrony (optimal versus nonoptimal testing times) and sleep quality. We analyzed the data of 36 evening-type and 36 morning-type young, healthy adults who completed the Compound Remote Associates (CRAs) as a convergent and the Just suppose subtest of the Torrance Tests of Creative Thinking as a divergent thinking task within a time interval that did (n = 32) or did not (n = 40) overlap with their individually defined peak times. Chronotype was not directly associated with creative performance, but in case of the convergent thinking task an interaction between chronotype and asynchrony emerged. Late chronotypes who completed the test at subjectively nonoptimal times showed better performance than late chronotypes tested during their “peak” and early chronotypes tested at their peak or off-peak times. Although insomniac symptoms predicted lower scores in the convergent thinking task, the interaction between chronotype and asynchrony was independent of the effects of sleep quality or the general testing time. Divergent thinking was not predicted by chronotype, asynchrony or their interaction. Our findings indicate that asynchrony might have a beneficial influence on convergent thinking, especially in late chronotypes.     

Reorganization of interhemispheric interactions during verbal-mental activity aimed at synthesis of words and sentences

Correlation and coherence analyses of multichannel electroencephalogram (EEG) recordings from 18 subjects (mean age 25 years) were used for investigating the reorganization of systemic interactions between bioelectric potentials of the cortical areas of both hemispheres (20 EEG derivations) during verbal-mental activity connected with generating verbal units from simpler components. When generating either words from aurally presented phonemes or sentences from a set of words, the subjects exhibited specific changes in the spatial structure of the statistical relationships in the EEG, with a significant increase in the interhemispheric interactions. During performance of both tasks, the changes in the interhemispheric interactions were most pronounced in the temporal, temporo-parieto-occipital (TPO), inferofrontal, and occipital areas of both hemispheres. Phonemic synthesis was associated with a more marked increase in the contralateral interactions in the left hemisphere, and generating sentences from words, in the right hemisphere. The coherence analysis of the EEG showed the greatest changes in the Δ, ?, and β frequency bands, with rather slight changes in the α frequency band. For all frequency bands, changes in the EEG coherences were the greatest in Wernicke’s and the TPO areas of the right and left hemispheres during the performance of both tasks, especially during the phonemic synthesis. These findings suggest that neurophysiological processes underlying mental generation of words and sentences require coordinated activity of the left and right hemispheres, which is accompanied by an increase in the interhemispheric interactions in the EEG, especially in the temporal, inferofrontal, and TPO areas.     

Age-related changes in the psychophysiological structure of intelligence and characteristics of its formation in young schoolchildren differing in academic progress

The psychophysiological structure of the verbal and nonverbal intelligence of children differing from one another in academic progress has been studied at the initial (six to seven years of age) and the last (nine to ten years of age) stages of studying at primary school. The age-related characteristics of the development and formation of a system of cognitive functions determining the efficiency of verbal and nonverbal activities in schoolchildren differing in academic progress have been determined. It has been demonstrated that the psychophysiological structure of intelligence in six-to seven-year-old and nine-to ten-year-old schoolchildren may characterize the cognitive strategy of their activity and is a criterion for early prediction of learning difficulties and a basis for developing individually oriented approaches to teaching and effective correction programs.     

Interhemispheric Differences Observed during the Performance of Cognitive Tasks Using Doppler Ultrasound

The article presents empirical data on the possible use of transcranial Doppler sonography as a method for the identification of functional specialization of hemispheres. We investigated intrahemispheric differences in the increase in blood flow velocity indicators during the performance of cognitive tasks with verbal and nonverbal stimuli in 20 healthy right-handed participants and 20 right-handed patients with local unilateral vascular brain lesions. We observed interhemispheric and intrahemispheric differences in blood flow velocity indicators between arteries during the performance of cognitive tasks with different variants of verbal stimuli in all participants. It has been found that one of the hemispheres plays a dominant role in verbal and nonverbal stimulus processing.     

Parameters of cortical interactions in subjects with high and low levels of verbal creativity

Parameters of cortical interactions depending on the level of creative achievements were studied in 40 right-handed subjects (22 men and 18 women). EEG was recorded at rest and during performance of a verbal creativity task (the Cognitive Synthesis test). The subjects were divided (by the median split) into groups with high and low originality scores (OSs). EEG coherence was computed within a range of frequencies from 4 to 30 Hz. The total values of coherence were determined separately for intra- and interhemispheric coherent connections using each of 16 electrode sites. Unlike subjects with a low OS, those with a high OS values were characterized by a decrease in the interhemispheric coherence of the θ_1,2-rhythm bioelectric potentials, which was especially pronounced in frontal cortical regions, and by an increased β₁-rhythm interhemispheric coherence in the occipital and temporal-parietal brain regions. The results are discussed in the context of right- and left-hemisphere contributions into the top-down and bottom-up regulation mechanisms during creative thinking.     

EEG study of the functional organization of the right and left hemisphere during solution of verbal and spatial problems

In adult healthy right-handed subjects, the expression and degree of synchronization of the EEG alpha-range rhythmic components in different areas of the right and left hemispheres, were studied in a state of quiet wakefulness and during solving of verbal and spatial tasks presented in the visual field. The EEG of quiet wakefulness was characterized by different distribution of the alpha-range rhythmic components in the right and left hemispheres; in the right hemisphere low frequencies (7.5-10.5 c/s) were more expressed and more coherent; in the left one--the high frequencies (10.5-13.5 c/s). The solving of tasks was accompanied--along with a decrease of the whole alpha-range power spectra both in the right and the left hemispheres--by a local increase of synchronization of certain components of this range; the increase was specific to the hemisphere and the kind of task. The increase of synchronization of low-frequency components was observed in the right hemisphere during solving of the spatial task and that of the high-frequency components was noticed in the left hemisphere during solving of the verbal task. On the basis of the data on hemispheric specificity of electric activity synchronization of the alpha-rhythm, a suggestion is made about a different character of the functional integration of the structures of the right and left hemispheres in the process of solving of spatial and verbal tasks.     

Comparative analysis of spatial EEG organization on models of non-verbal divergent and convergent thinking

Features of neurophysiological organization of two main thinking types playing different roles in creative processes, i.e., divergent and convergent were studied with participation of 30 right-handed male subjects at the age from 30 to 50 years. Two tests were presented: (1) creation of many visual images on the basis of two simple geometrical figures (the model of divergent thinking) and (2) classification of a figure element with one of the offered standard samples (convergent thinking). The number of created images or correctly classified elements for five minutes served a criterion of performance productivity. It was found that performance of the divergent test with high productivity (as compared to low productivity) was characterized by a greater increase in non-linear interactions between the cortical potentials, especially in the axis right frontal--left occipital areas. At the same time, under conditions of high productivity, the number of active narrow-frequency spectral-coherent EEG bands increased. The data confirm the notion of neurophysiological organization of creative processes, according to which creative processes require the intensification of retrieval operations (both conscious and unconscious), based on extensive interhemispheric interaction and involvement of a system of EEG coherent structures oscillating with different frequencies.     

Influence of informational oversaturation on the quality of creative activity and spatial organization of EEG

The features of the spatial organization of bioelectric potentials in the cases of successful and unsuccessful creative imagination (refusal or poor quality of the product) under conditions of informational oversaturation. Two groups of subjects were compared: professionals (23 healthy students of the Department of Graphic Arts) and non-professionals (34 persons whose specialties were not linked with systematic visual imagination). During the experiments, the subjects were asked to mentally create a visual image based on two simple graphic elements, a right angle and a diagonal; after recording the EEG, they had to draw the image on paper and give it a title. The total number of elements exceeded 7 ± 2; hence, information processing at the conscious level was impossible, which caused the necessity of involving the mechanisms of unconscious information processing. The quality of the created product was evaluated with regard to the degree of success of performing the task and the features of spatial EEG organization. The EEG was recorded from 24 scalp sites of a subject using a SIT-EEG portable telemetric device. In the case of the successful performance of the task by professionals, the parameters of spatial organization of bioelectric potentials, i.e., spatial synchronization (linear processes) and spatial disorder (non-linear process) were strengthened compared to the base-line level in the frontal temporal areas of the right hemisphere and parietal occipital areas of the left hemisphere. Conversely, in the nonprofessionals, these parameters increased in the frontal temporal areas of the left hemisphere and parietal occipital areas of the right hemisphere. In the case a task was not successfully performed by the professionals, the spatial disorder of bioelectric potentials increased in all the cortical areas; in the nonprofessionals, only weak changes were observed. In all situations, the groups differed also in the parameters of coherence (Coh), spectral power (Sp) of bioelectric potentials, and informational energy, which reflects the level of expenditure of the brain’s energy for information processing. The evidence obtained is interpreted in terms of electroencephalographic correlates of successful task performance by professionals and nonprofessionals, i.e., their creative imagination under the conditions of informational over-saturation.     

The influence of reward on the performance of verbal creative tasks: Behavioral and EEG effects

The goal of this study was to compare the effects of the verbal instruction (IN1) that stimulated originality and of monetary reward (IN2) on the efficiency of performing a verbal creative task. The EEG patterns were also compared on the basis of mapping the bioelectric potential power within the frequency range of 4 to 30 Hz. Right-handed students (10 men and 10 women) participated in the experiment. The originality of the solution improves if a monetary reward is expected. In contrast to IN1, the promise of a monetary reward caused a global increase in task-related synchronization of bioelectric potentials in the θ₂ band. Hemispheric asymmetry of the power of the θ₁, θ₂, and α₂ rhythm grows with higher values in the right hemisphere. These changes in response to IN2 were in the background EEG, which testifies that an overall increase in hemispheric asymmetry induces a preparatory state after the promise of monetary reward. Specific changes in regional brain activity were at the β₂-rhythm frequency. In all posterior derivation, except for the frontotemporal ones, the power of the β2 rhythm decreased in response to IN2 in contrast to IN1. The rewardinduced changes in EEG were characteristic of men to a greater extent. An increase in the θ₂-rhythm asymmetry and the power of the α rhythm was observed only in men in response to a monetary reward. Our results suggest that the promise of monetary reward is favorable for creative thinking and original solutions. Gender differences of changes in the power of bioelectric potentials suggest that the neurophysiological mechanisms of creativity are different in men and women.     

Interaction between the Frontal and Left Parietotemporal Areas in Verbal Thinking

The synchronization of the rhythmical components of evoked potentials (EP) was studied during verbal-task solving. A novel method of the calculation of Wavelet curve correlation was used to reveal synchronization between the evoked rhythmical components in short time intervals. This method was applied to earlier EP records, which were conducted during the search for verbal associations and revealed the successive activation of the frontal and left parietal cortical areas. Two stages of task solving were identified. Independently of the task type, the first stage was characterized by a diffuse synchronization in a broad frequency band below 22 Hz immediately after the stimulus presentation. This stage results in a realization of the verbal stimulus. The second stage was manifested in a localized synchronization between the frontal and left temporal (Wernicke's) areas in the narrow frequency band about 17 Hz only during search for associations. This specific and local synchronization took place earlier than the diffuse activation of the left temporal cortex. This stage appears to reflect the information transmission from the frontal cortex to the left parietotemporal area.