RESUMEN

OBJECTIVE: The clinical and demographic factors associated with mild cognitive impairment (MCI) and the topographical features of electroencephalogram (EEG) spectral power in patients with coronary artery disease (CAD) depending on the presence or absence of MCI were studied. MATERIAL AND METHODS: Seventy-five male patients with CAD were assigned to the groups with (n=31) and without MCI (n=44). The control group included 15 healthy people (the mean age 60.0 ± 4.39 years). The MMSE, the Frontal Assessment battery, the Trail-Making Test, Khanin-Speilberger and Beck depression scales were used. RESULTS: A lower level of education, more severe coronary lesions and lower cardiac contractility, as well as higher spectral power (Θ-rhythm) of parietooccipital theta activity have been found in CAD patients with MCI compared to patients without MCI. The latter parameter in MCI patients also differed from controls. CONCLUSION: Education is an important factor to preserve cognitive abilities in patients with CAD. In addition, the severity of coronary artery lesions and low cardiac contractility affect the degree of cerebral ischemia and neuronal dysfunction detected by spectral EEG power. The efficacy of quantitative EEG analysis methods for early detection and prevention of cognitive disorders in CAD patients was confirmed.

Asunto(s)

RESUMEN

The aim of this study was to compare the effects of stimulating originality verbal instruction (IN1) and monetary reward (IN2) on originality of solutions of a verbal creative task and EEG-correlates of activity, determined on the basis of biopotentials power mapping in the frequency range 4-30 Hz. Right-handed students (10 men and 10 women) took part in experiment. An increase of solutions originality under the influence of monetary reward was revealed. At the promise of monetary reward in comparison with IN1, there was a global increase of the task-related theta2 power. Common to the teta1, 2 and alpha2 bands was increase in hemispheric asymmetry of these rhythms power with higher values in the right hemisphere of the brain. These changes have been observed already in the background EEG after IN2 and testify that generalized changes in hemispheric asymmetry provide the preparatory state after the promise of monetary reward. Regional brain activity changes were associated with beta2 rhythm. Under IN2 in comparison with IN1 the task-related power decreased in all posterior electrode sites except for frontotemporal. Reward-related EEG changes were more typical for men. In men only, promised monetary reward increased theta2 asymmetry and task-induced alpha power. Our results suggest that promise of monetary reward for creative thinking can increase verbal creativity. Gender differences in the reward-related EEG power changes show that men and women differ in neurophysiologic mechanisms that underlie increase of creativity.

Asunto(s)

RESUMEN

Sex differences in creativity related global-local hemispheric selective processing were examined by hierarchical letter presenting in conditions of their perception and comparison. Fifty-six right-handed males and 68 females (aged 17-22 years) participated in the experiments. Originality-imagery was assessed by a computer-based Torrance 'Incomplete Figures' test software. Verbal creativity was valued by original sentence using of three nouns from remote semantic categories. The results show that irrespectively of the sex factor and the type of creative thinking, its originality is provided by high speed of right-hemispheric processes of information selection on the global level and delay in the interhemispheric communication. Relationships between originality of ideas and hemispheric attentional characteristics are presented mostly in men while verbal creative problem solving, and in women while figurative original thinking. Originality of verbal activity in men is more associated with success of selective processes in the left hemisphere, but in women--with selective functions of both hemispheres. Figurative thinking in men is less related to hemispheric characteristics of attention compared with women. Increase of figurative originality in women is accompanied acceleration of processes of selection of the information in the right hemisphere, and also higher efficiency of local attention as well as speeds ofglobal processing in the left hemisphere.

Asunto(s)

RESUMEN

We studied the changes of electroencephalograms (EEG) related to on-pump coronary artery bypass grafting (CABG) in 28 right-handed male patients with coronary heart disease (CHD), 10 from which had accompanying moderated (30-50%) carotid artery (CA) stenoses. All EEG studies were performed 3-5 days before and 7-11 days after CABG. EEG data of healthy age-matched males (n=14) were examined. Before surgery, the CHD patients differed from the control group by less expressed theta2 and beta1 rhythm power asymmetry. The differences demonstrated worse conditions for cognitive processes in CHD patients. After CABG, the higher power of teta1 and 2 rhythms, predominantly in the frontal lobe of the left hemisphere which was mostly expressed in patients with CA stenosis, was observed in all CHD patients. This effect can be considered as the appearance of ischemic neuronal injury caused by on-pump CABG. The localization of changes in the frontal cortex of the left hemisphere can be related to a high vulnerability of these regions. The deficit of cerebral blood flow in these regions will define a clinical picture of cognitive decline after CABG.

Asunto(s)

RESUMEN

Analysis of EEG correlates of figural creativity (Torrens "Incomplete figures" subtest) and its efficacy after the instruction "to create an original solution" (condition I) and after the same instruction with the promise of a monetary reward for high performance (condition II) was carried out. Fifteen right-handed men and 16 women were examined. In condition II, the image originality was not increased, but performance fluency was reduced as compared to condition I. Promise of the monetary reward in condition II was followed by a decrease in the theta1-rhythm power before the task performance, which persisted during the image creation. Baseline values of the power of rhythms alpha1 and 2 were higher in condition II as compared to condition 1. Promise of the monetary reward in condition II was associated with a reduction of the experimental beta1- and beta2-rhythm power in posterior regions of the cerebral cortex. These effects may be associated with pre-setting to the forthcoming activity and task performance under increased extrinsic motivation. The enhancement of external motivation in condition II also induced changes in hemispheric power asymmetry of the teta1-, alpha1, and beta2-rhythm at the expense of the left-hemisphere activity, which may be the basis of different effects of high motivation levels on subjects, who preferred right or left hemispheric strategies during figural divergent thinking.

Asunto(s)

RESUMEN

The EEG mapping study tested age-related changes in power of EEG rhythms from delta to gamma ranges under healthy cognitive aging associated with preserved cognitive abilities and involvement in complex professional activity. 32 subjects of higher age group (HAG, mean age 65.1 +/- 1.18, 14 men and 18 women) and 33 subjects of lower age group (LAG mean age 22.1 +/- 0.38, 18 men and 15 women) participated in the study. Mean power of slow (delta, theta and alpha2) activity decreased and of fast activity (beta, gamma) increased as subject age increased. Compared to subjects of LAG subjects of HAG displayed a reduction in heterogeneity of EEG activity across recording sites. Centro-temporal gradients of power for frequency ranges from delta to beta2 and frontoparietal gradients and hemispheric asymmetry for alpha and beta1 rhythms were smoothed in subjects of HAG. These results suggest that observed age-related changes in baseline EEG may be the prerequisite for compensatory neural recruitment that may be associated as with allocation of more resources in cognitive processes so with reorganization of cortical networks including areas susceptible to physiological changes with aging.

Asunto(s)

RESUMEN

Sex differences in global-local hemispheric selective processing were examined by hierarchical letter presenting in conditions of their perception and comparison. Fifty-six right-handed males and 68 females (aged 17-22 years) participated in the experiment. During interference between global and local aspects of stimuli the mean reaction times for correct global responses was quicker than local responses, and the right hemisphere has been dominated during global selective processing independently from the sex. Sex differences in perception of visual hierarchical stimuli were more pronounced than in comparison condition: men prefer mostly the right-hemispheric global strategy of information processing, but women--the left-hemispheric local one. Dominance of global strategy in men and local strategy in women during visual hierarchical stimuli perception together with no sex differences in correct responses indicates possibility of similar results in cognitive activity by different ways.

Asunto(s)

RESUMEN

The interrelations between the level of creative ability and features of baseline power and event-related desynchronization/synchronization (ED/ES) of the theta and beta rhythms during a figural creative task (Torrance Test "Incomplete figures") in conditions of different motivation were studied. Increased motivation was induced by instruction "to create most unique images" in comparison with instruction "to create images". The subjects, right-handed students (14 males and 14 females), were divided into groups with high and low originality scores. Baseline theta2 and beta1,2 power and ED/ES of the rhythms were related to creativity level and sex of participants. These relationships were found only under instruction "to create images". Males with higher originality scores differed from males with lower originality scores by more pronounced ED in temporal-parietal-occipital regions of the brain. Such differences were absent in women. In the betal band, during task performance the high-creative men demonstrated ED in contrast to ES that was demonstrated by the high-creative women. Analysis of the beta1,2 reference power showed that only in the high-creative women beta1 power was higher in the caudal then in the frontal hemispheric regions. The high creative participants of different genders had different laterality patterns of activity in electrode loci Fp1/2 (betal) and Fp1/2, F7/8 (beta2). The obtained results allow to suggest that high creativity in men and women is related to gender specific patterns of frontal-occipital and lateral organization of activity of theta and beta brain oscillators.

Asunto(s)

RESUMEN

The characteristics of cortical interactions depending on level of creative achievements were investigated in 40 right-handed subjects (22 men and 18 women). The subjects were divided into the two groups with high and low ability by the originality score median split. EEG was recorded in rest and during task performance (the verbal creative task "Cognitive synthesis"). EEG coherence was computed in the six frequency range from 4 to 30 Hz. Total values of coherence for each of 16 sites, calculated separately for intrahemispheric and interhemispheric connections were analyzed. It was revealed that subjects with higher originality scores (OS) in comparison to low original ones were characterized by decreased the theta 1.2 rhythms interhemispheric coherence, that was expressed in the frontal cortex, and increased beta1-rhythm interhemispheric coherence in the occipital and temporoparietal regions of the brain. The obtained results are discussed from the point of view of the contribution of the right and left hemispheres of the brain to processes "top-down" and "bottom-up" regulation during creative thinking.

Asunto(s)

RESUMEN

Creativity-related changes in alpha power in low-frequency (8-10 Hz) and high-frequency (10-13 Hz) bands were studied in university students having regard to generation of original ideas during performance of two verbal tasks. A high-creative group enrolled 16 subjects asked to generate original words--associates to the triads of verbal stimuli and 14 subjects who were asked to compose a sentence using triads of nouns from remote semantic categories. Low-creative groups included 22 and 13 individuals, respectively. In low-frequency band, highly creative subjects showed a higher level of alpha power than low creative individuals. In the high-frequency band, task-related alpha2 power desynchronization was different in these groups: high-creative individuals had higher power score than low-creative mostly in the anterior and parietal cortical areas. These data and a factor structure of alpha rhythm indices may be evidence of different strategies of information selection in highly and low creative persons.

Asunto(s)

RESUMEN

The study was aimed to explore the features of interaction between cortical areas during figural creative task performance in high- and low-creative men and women. We divided the participants into two groups with high and low creativity by the median of originality score. EEG was recorded at rest and during task performance (Torrance Tests of Creative Thinking "Incomplete figures"). The EEG coherence was computed in six frequency bands from theta1 to beta2. We analyzed the total values of coherence for each of 16 sites, calculated separately for intrahemispheric and interhemispheric connections. In the theta2, alphal, and alpha2 bands, coherence values decreased in task performance as compared to baseline in subjects with lower originality scores, whereas in subjects with higher scores, they increased in the theta2 and alpha1 bands. The decrease in the alpha2 band in the higher-creativity group was significantly lower in comparison with the decrease in the lower-score group. In the alpha2 band, the interaction of gender, creativity, laterality, and electrode position factors was also found during analysis of task-induced coherence changes. Further examination of the interaction showed the similarity of EEG coherence patterns in men and women with opposite creative abilities and higher values of task-induced coherence changes in the anterior regions of the left hemisphere and posterior regions of the right hemisphere in high-creative in comparison with low-creative men. The findings are discussed in terms of different cognitive strategies used by men and women that may have the same results in creative problem solving.

Asunto(s)

Asunto(s)

RESUMEN

Patterns of EEG coherence changes induced by performance of a verbal creative task were studied in 14 male and 13 female university students. EEG coherence was computed for six frequency bands in the range from 4 to 30 Hz. Experiment consisted of two series: in the first series, the task was performed under the instruction "to create sentences", in the second series under the instruction "to create original sentences". Independently of the instruction, coherence reactivity values (data of the experiment minus corresponding baseline data) were negative in the tetal and alpha2 ranges and positive in the beta2 range in all subjects. Sex differences related to the type of instruction were found in changes in the total reactivity values of intrahemispheric coherence (sum of intrahemispheric coherence reactivity values for the all frequency bands studied). The task performance under the instruction "to create original sentences" vs. the task performance under the instruction "to create sentences" was accompanied by changes of the right-hemispheric dominance (i.e. higher values of coherence in the right hemisphere than in the left hemisphere) to the left-hemispheric dominance in women and the opposite effect in men.

Asunto(s)

RESUMEN

Effect of extrinsic motivation stimulating the most original problem solving during verbal and figural creativity testing was studied using the EEG coherence in the range of 4-30 Hz. The right-handed university students (27 males and 26 females) participated in the experiments. The instruction "to create the most original solution" (INS2) as compared to the instruction "to create any solution" (INS1) produced an increase in baseline coherence and task-related desynchronization in the alphal2 bands. This effect was more pronounced in the anterior cortex. Changes in the beta2 rhythm were found mostly in the posterior cortex and were presented by a decreased task-induced beta2 synchronization after INS2 vs. INS1. Instruction-related coherence changes in the alphal band did not depend on factors of gender and task type, whereas the effects of these factors on the alpha2 and beta2 bands were significant. Gender differences in instruction-related coherence changes were found in the alpha2 band during verbal creativity testing, whereas figural creativity was associated with gender-dependent instruction-related changes in the beta2 band. These differences were more pronounced in the INS1 condition. The results demonstrate that extrinsic motivation of creative thinking promotes the frequency-specific reorganization of hemispheric interactions. High-frequency widespread cortical oscillations are of greater significance in men, whereas low-frequency rhythms and, mainly, functioning of the frontal cortex greatly contribute to creative activity in women.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

Relationships between creative abilities and indices of selective attention were studied in lateralized serial Stroop Test presented in two conditions: color and word integrated or separated in a stimulus. The study enrolled 69 male and female subjects who were divided into high- and low-creative achievement groups by mean split of the originality score in figural tasks of Torrance Tests of Creative Thinking. It was found that features of hemispheric organization of selective attention assessed by the difference in reaction time to incongruent and a congruent color-word stimuli pairs individually administered in the right and left visual hemifields were differently correlated with creative abilities of men and women. High creativity of men was associated with lower attention-related selective processes in the right hemisphere and inversion of hemispheric asymmetry (as compared to low-creative men). There was no difference in these parameters between high- and low-creative women. Independently of gender, hemispheric asymmetry of selective attention indices reversed after transition from integrated to spatially separated presentation of color and word, which provided evidence for the use of flexible strategies.

Asunto(s)

RESUMEN

The role of gender in the functional organization of the hemispheres was studied in relation to the conditions of focusing of attention during the memorization of competitively presented verbal information. Analysis of the reactivity of the coherence of cortical biopotentials in six frequency ranges (4-30 Hz) showed that voluntary selection of information from one auditory channel, as compared with the situation in which attention was distributed between both ears, was accompanied by an increase in the anterofrontal interaction in men and in the parietal-occipital areas of the cortex in the theta1 range in women. In the beta1 range, focusing of attention to the right or left ear during memorizing of words was associated with a contralateral increase in intrahemisphere coherence in men, while there were no significant changes in coherence in women. Changes in coherence in the theta1 and beta1 rhythms, depending on the conditions of distribution of attention and the nature of correlational connections between the reproduction of words and the patterns of reactivity of coherence in these frequency ranges, suggest that word remembering in men is associated mainly with a dominance of regulatory influences from the anterior attention system, while in women it was associated mainly with the posterior system.

Asunto(s)

RESUMEN

Features of EEG pattern during verbal creative thinking depending on experimental instruction were studied in men and women. Spectral power density was analyzed in six frequency bands (4-30 Hz). Performance of a creative task produced an increase in the power of theta (4-6 Hz) and beta2 (20-40 Hz) components and decrease in the power of alpha (8-13 Hz) and betal (13-20 Hz). Changes in the alpha and betal bands were observed, predominantly, in the posterior areas, whereas power of the thetal and beta2 bands increased in the anterior areas. Independently of instruction, women demonstrated greater synchronization in the theta1 band than men, whereas in men the desynchronization in the alpha2 band (10-13 Hz) was more pronounced. When the subjects were instructed to create original sentences, a widespread decrease in the EEG power was observed in the band of 8-30 Hz as compared to instruction "to create sentences". Thus, the instruction-related changes in EEG power were not gender-specific. They may reflect neural activity mediating selective attention.

Asunto(s)

RESUMEN

Gender-related differences in EEE coherence were studied in young male and female university students during performance of Stroop task, in which color and word could be congruent or incongruent and spatially integrated or separated. The most clear-cut gender-related differences in the EEG coherence were revealed in the alpha2 and beta frequency bands. In the alpha2 band, gender-related differences in the interhemispheric coherence were associated with spatial characteristics of stimuli: left or right presentation and features of mutual localization of relevant and irrelevant stimuli. These differences were observed when information was addressed to the left hemisphere. Gender-related differences associated with spatial organization of stimuli were also observed for intrahemispheric beta1 coherence. Under conditions of the spatial separation of relevant and irrelevant stimuli, only females demonstrated enhancement of coherence in response to the right-side stimulus presentation as compared to the left-side presentation. It was shown that, during the differentiation of the semantic meaning of verbal stimuli, gender-related differences were caused by the features of integration of beta2 oscillators in the posterior cortical regions. The results are indicative of qualitative gender-related differences in organization of both frontoparietal and lateral attention systems in actualization of selective processes.

Asunto(s)

RESUMEN

Gender differences in the functional hemispheric organization during memorization of dichotically presented verbal information in the situation of focused or non-focused attention were studied. Analysis of EEG coherence reactivity in six frequency bands (4-30 Hz) showed that the focused attention to stimuli presented to one ear as compared to divided attention between both ears was accompanied by an increase in the interhemispheric interaction in the thetal frequency band between the frontal cortical areas in men and between the parietoccipital areas in women. In the betal band, the focused attention was associated with a contralateral increase in the intrahemispheric coherence in men, whereas no significant difference in the intrahemispheric coherence was found in women. On the basis of coherence changes in the thetal and betal bands depending on the attention conditions together with the obtained correlation between coherence reactivity and word-recall scores, it may be suggested that verbal memorization in men is associated, predominantly, with the regulation from the anterior system of attention and from the posterior system in women.

Asunto(s)