Spatial Organization of Alpha Range Potentials on EEG and Logical Thinking Effectiveness.

We studied spatial organization of EEG alpha range potentials in volunteers with different results of tasks requiring logical thinking. The examinees with higher cognitive test performance have more labile coherent associations of EEG alpha range potentials, which manifested in changes in the level and structure of these associations at different stages of the test. In individuals with poor results, the number of significant coherent associations and their structure do not change during the problem solving process.

[Dynamics of EEG Alpha-Activity and Heart Rate Variability in Subjects Performing Cognitive Tests].

Changes in the power and coherence of α-activity and heart rate variability (HRV) were studied in students with different performance levels in logical tasks. In those students who reached high scores in the cognitive tests, we observed higher lability of α-activity and HRV; the values and their ratios varied among the stages of intellectual activity. In these subjects, a decrease in the spectral power of α-band was more pronounced than in other groups. We also observed changes in the interhemispheric coherence and in the structure of coherent interactions in the α-range at different stages of task performance. In contrast, the number and structure of coherent interactions in individuals who showed lower results did not significantly vary at different stages of task performance. As compared with this group, the students with higher test results showed a more pronounced decrease in the total spectral power (TP) and an increase in the low frequency/high frequency (LF/HF) ratio which returned to the initial level after the end of the tests. In students with better results in these cognitive tests, the dynamics of RRNN, TP, HF, and LF/H F during task performance correlated with the dynamics of interhemispherical α-band coherence.

Dynamics of heart rhythm characteristics and efficiency of intellectual activity during computer work.

Heart rhythm variability characteristics were studied in volunteers with different stability of the results upon switching from one type of intellectual activity to another. Individuals with stable results differed from those with worse accuracy of information reproduction by high initial CV, total power of heart rhythm variability and power of VLF, LF, and HF spectra. Volunteers with stable results were characterized by high lability manifesting by changing values and proportions of heart rhythm variability characteristics at different stages of activity and by the absence of a relationship between these parameters at different stages of activity and initial status of the volunteer. VLF spectrum power decreased with impairing the accuracy of information reproduction.

[Motivation effect on EEG spectral power and heart rate parameters in students during examination stress].

EEG spectral power was calculated in 24 students (18-21 years) with different levels of motivation and anxiety (tested by Spielberger) in two experimental conditions: during the common educational process and the examination stress. Before examination tests, in subjects with high motivation and anxiety level the relative delta activity power increased in right frontal (F4) brain areas. In students with medium motivation immediately before an examination the relative beta2-activity power increased in right frontal (F4) brain areas. It is suggested that delta oscillati- ons reflect activity of the defensive motivational system, whereas beta2 oscillations may be associated with the achievement motivation.

[Spatial organization of the beta2 EEG frequency band and effectiveness of the intellectual activity in humans].

Features of spatial organization of the beta2 EEG frequency band were studied in subjects with different speed and accuracy during task performance of the memorizing and subsequently reproducing of the sequence of signals on monitor screen. Students who had reached a high speed and accurately performed intellectual tasks were characterized by high lability of the coherent relations in the beta2 EEG range, which manifests itself in a significant coherence increase during memorization and reproduction of the signal sequence compared to the initial state. In contrast, in individuals who needed more much time for making decisions and mistakes, the number and structure of coherent relations from stage to stage of activity considerably did not change.

[Geometrical images of coherent interrelations of biopotentials of EEG different frequency ranges in dynamics of humans goal-directed behavior].

Spatial organization of teta, alfa, beta-1, beta-2 in EEG potentials in humans who quickly an with a high accuracy performed task to learn and reproduce on PC monitor a definite sequence o accuracy performed task to learn and reproduce on PC monitor a definite sequence of circles wer studied. It was found that geometric images of coherent interrelations of teta, alfa, beta-1, beta-2 in EEG potentials were dynamically changed on the different stages of goal-directed the humans activity. The studies give the grounds to consider dynamically changed geometrical images of coherent links of different EEG potentials as an objective index of external projection of intracerebral processes of system architectonics of goal-directed behavior on brain cortex.

Dynamics of heart rate parameters in students with various personal anxiety levels during computerized testing.

Students with low level of initial (pre-test) personal anxiety demonstrated a high level of modulating effects on the heart rate in all basic frequency ranges (VLF, LF, and HF) resulting in a greater total power of heart rate variability spectrum compared to students with high personal anxiety. The peculiarities of dynamics of heart rate variability were revealed during a real learning task, which correlated with personal anxiety level. In comparison with highly anxious students, the low-anxious group demonstrated more pronounced drop in the power of all ranges of the heart rate variability spectrum during testing followed by restoration of these power indices to initial levels after completion of the test. In contrast, the drop of the total power of the heart rate variability spectrum and in the power of its individual components persisted in students with high anxiety level even after the end of the testing.

[Students' knowledge level computer testing results and individual specificity of purposeful activity vegetative support].

The vegetative correlates of individual differences in the effectiveness of the purposeful activity during computer sensory motor test and computer testing of the level of knowledge of students were studied. For the students, who reached the high results of sensory motor and training tests it was characteristic the lability of vegetative indices, which is manifested in a change in the absolute values and relationship of the characteristics of heart rate and hemodynamic in accordance with the stages of activity. These changes were specific for each of the forms of activity and connected with the results of tests. By the physiological prerequisites of the high lability of vegetative characteristics, which ensures the capability of the subject successfully to be adapted for the conditions of activity, appeared high initial values TP, power LF and HF of the ranges of spectrum.

[Geometric imaging of coherent interrelationships of electroencephalogram α-rhythm in dynamics of system effective human activity].

In subjects performing tasks quickly and precisely, geometric imaging of coherent connections among the EEG alpha-range potentials dynamically changed and turned out to be specific for each of the intended activity's stages. In the subjects performing tasks slowly and with errors, in different stages of effective human activity, a stability of the geometric image was observed. The revealed geometric imaging changing in different stages of effective activity seems to reflect a multi-level organization of the action results acceptor.

[Spatial organization of biopotentials and decision-making time during purposeful mental activity in humans].

Features of spatial organization of neocortical potentials were studied in subjects with different decision-making time during performing the task of memorizing and subsequently reproducing, on a monitor screen, a sequence of signals. The subjects with a short decision-making time differed from those with a long decision-making time in a higher level of the intra- and interhemispheric coherence in alpha EEG frequency band different neocortical areas during reproduction of a signal sequence (coherence in the frontal, central and parietal areas; coherence between the right central and the left frontal, central, parietal, occipital and temporal areas; coherence between the left occipital and both the frontal areas).

[EEG correlates of individual differences in performance efficiency of students during examination stress].

Performance of cognitive tests and EEG spectral power were evaluated in 39 students aged from 19-21 years in two conditions: during common educational process and immediately before examination (stress condition). Before examination, the performance was better in subjects with low level of spectral density in the delta band (in the occipital, parietal, central and frontal cortical areas) and high level of the alpha-rhythm spectral density in all the cortical areas, A decrease in performance scores before examination was correlated with an increase in the delta activity (in the right frontal and temporal cortical areas) and rise of the anxiety level (tested by Spielberger).

[Spectral EEG characteristics in students with different anxiety profile during tests]. / Spektral'nye kharakteristiki EEG u studentov s razlichnoi lichnostnoi trevozhnost'iu v situatsii ékzamenatsionnogo stressa.

EEG spectral power was calculated in 39 students at the age of 19-21 years in two experimental conditions: during the common educational process and immediately before an examination (stress condition). During the education process, in subjects with high anxiety (tested by Spielberger) the relative spectral power of the delta activity was higher than in the other group in the occipital, parietal, central, and right frontal brain areas, whereas the power of the EEG alpha in these areas was lower. Before examination tests, in subjects with high activity the delta power bilaterally increased in the temporal areas, whereas in subjects with low anxiety there was a decrease in the alpha rhythm power, especially in the right frontal area. In stress condition, the relative power of the delta activity in both occipital and temporal, right parietal and central areas was higher in subjects with low anxiety, whereas their alpha power was lower in both frontal and in occipital, parietal, and temporal areas of the left hemisphere.

[Energy metabolism in students depending on motivation during exams]. / Energoobmen u studentov vo vremia ékzamena v zavisimosti ot urovnia motivatsii.

The energy metabolism (EM) was shown to significantly depend upon the motivation level in students during examination. Energy expenditure increased before the examination in low- and medium motivation groups but not in highly motivated students.

[Relaxing effects of local heat-air exposure under stresses in students]. / Relaksiruiushchie éffekty lokal'nogo teplovozdushnogo vozdeistviia v usloviiakh stressovykh nagruzok u studentov.

The relaxing effects of local heat-air exposures (TAE) on man (60 male students aged 19-21 years) were studied using a specially designed device which may control temperatures and time on an individual basis depending on the examinees' sensation of a positive emotion. On study days and under examination stress. TAE was shown to reduce situation-induced anxiety, to increase the duration and variability of R-R intervals on ECG, to make EEG right-frontal delta- and theta-indices lower and EEG right occipital and frontal alpha-index higher. The range of visual accommodation increased. The findings suggest that the proposed graded local heat-air exposure procedure is an effective tool of relaxation and prevention of negative effects of emotional stress.

[The individual characteristics of the physiological support for the activities of schoolchildren while learning to work on a computer]. / Individual'nye osobennosti fiziologicheskogo obespecheniia deiatel'nosti shkol'nikov pri obuchenii rabote na komp'iutere.

The ECG was recorded by telemetry in schoolchildren when they learned computer tasks. Successfulness of learning was estimated. The EEG was recorded with the same psychophysiological parameters (simple and complex reaction times, search for orders of numbers in special tables and others) under the laboratory conditions. Neuroemotional stress (NES) during computer learning as measured by the heart rate parameters was shown to depend on the stable individual characteristics. NES was significantly higher in introverts than in extraverts (determined by Eysenck's questionnaire). The most prominent physiological signs of NES were revealed at the stages of computer task learning when mistakes in computer programs were searched for and corrected. The speed of learning of computer tasks was found to be proportional to a lability of autonomic heart rate regulation and to be correlated with such psychophysiological parameters as decision making time, the number of false preliminary reactions and others.