A.R. Luria's theory describes a structural and functional block that regulates the sleep-wake cycle and is involved in the awakening process. However, the features of interhemispheric asymmetry during awakening from different sleep phases remain insufficiently studied. There are practically no works on the EEG rhythms coupling during the restoration of activity immediately after awakening. Identification of differences in the functioning of the cerebral hemispheres (within the framework of A.R. Luria's theory) upon awakening with varying efficiency of restoration of psychomotor activity. Identification of the connectivity of simultaneously functioning brain structures in 1 block according to A.R. Luria. Data from 15 of 83 participants who completed the entire study procedure were used for the analysis. Multichannel EEG was recorded in parallel with the bimanual psychomotor test. The power characteristics of the EEG were assessed based on the "mother" complex Morlet wavelet. The Kendall correlation coefficient served as a measure of the amplitude-amplitude interaction of EEG rhythms. Complete awakening is characterized by the presence of asymmetrical connections of EEG rhythms in both hemispheres. Incomplete awakening is accompanied by rhythmic connections in the left hemisphere only. The asymmetry of EEG rhythm coupling is observed in the frontal and temporal regions of the left hemisphere and in the frontal regions of the right hemisphere only during complete awakening. With incomplete awakening - in almost all areas of the left hemisphere. The performance of the psychomotor test is characterized by different efficiency of activity recovery after sleep, and different levels of efficiency are characterized by differences in the functioning of the hemispheres according to the EEG rhythm coupling. Connections between EEG rhythms were identified, on the basis of which an assumption was made about the coupled work of the thalamocortical and cortico-hippocampal systems within the 1 block according to A.R. Luria. Both types of awakening were characterized by the participation of all structural and functional blocks according to A.R. Luria, differing in the hemispheres depending on the type of awakening. Complete and incomplete awakenings are characterized not only by a different set of asymmetric EEG rhythm connections in the hemispheres, but also by their localization.

Objectives . To study interhemispheric asymmetry (IHA) by electroencephalography (EEG) in healthy subjects during cognitive waking from stage II daytime sleep prior to recovery of the performance of a psychomotor test. Materials and methods. IHA of the amplitude-amplitude coupling of EEG rhythms was studied in healthy adult subjects using 20-sec trace segments recorded in the state preceding spontaneous waking, as defined by the moment the α rhythm appeared on the EEG, and the subsequent onset of psychomotor activity. The state of subjects during this period (the initial stage of so-called cognitive waking preceding behavioral waking), when theperson is unable to movebut is able to perceive external stimuli, is an experimental model for identifying signs of conscious activity in patients coming out of coma. Wavelet transformation was used to compute the rhythmic characteristics of bioelectrical activity. The Kendall correlation coefficient served as a measure of interactions between rhythms. Results. IHA of the interaction of EEG rhythms was found to be dynamic in nature and to be formed due to the connections of the θ rhythm with the α2 and β rhythms in the left hemisphere of the brain and δ–θ connections in the right. Conclusions. The marked left-hemisphere asymmetry is probably associated with the onset of the retrieval of instructions from memory, which subsequently allows return to the activities interrupted by sleep.

исследовались распространенность и особенности вегетативной дисфункции у студенток младших курсов медицинского вуза. Высокий уровень вегетативной дисфункции в сочетании с низким уровнем личностной тревожности у испытуемых в меньшей степени влияет на состояние здоровья и качество жизни, чем сочетание низкого уровня вегетативной дисфункции и высокого уровня личностной тревожности. The prevalence and peculiarities of autonomic dysfunction in female undergraduate medical students were investigated. The presence of a high level of autonomic dysfunction in combination with a relatively low level of personal anxiety influences the state of health and quality of life to a lesser degree than a combination of a relatively low level of autonomic dysfunction and a high level of personal anxiety.

OBJECTIVE:To study interhemispheric asymmetry (IHA) according to electroencephalography (EEG) data of a healthy person during cognitive awakening from the second stage of daytime sleep before restoring the performance of the psychomotor test.MATERIAL AND METHODS:In 23 healthy adult subjects, we studied IHA in the amplitude-amplitude interaction of EEG rhythms for 20 sec segments before spontaneous awakening determined by the moment the alpha-rhythm appearance on the EEG and the subsequent onset of psychomotor activity. The state of the subject during this period (in the initial stage of the so-called cognitive awakening preceding the behavioral awakening), when the person is unable to move, but is able to perceive external stimuli, is an experimental model for highlighting signs of conscious activity of patients when coming out of a coma. Wavelet transform was used to calculate the rhythmic characteristics of bioelectrical activity. The Kendall correlation coefficient served as a measure of rhythm interaction.RESULTS:IHA in the interaction of EEG rhythms is dynamic nature and formed by theta rhythm connections with alpha2- and beta-rhythms in the left brain hemisphere and delta-type connections in the right.CONCLUSION:Possibly, the greater activation of the left hemisphere is related to the retrieval of an instruction from memory, which subsequently allows to return to the activity interrupted by sleep.

This article addresses contemporary concepts of the neurophysiological mechanisms of awakening from sleep and the results of our own electroencephalographic (EEG) studies of the temporospatial dynamics of activity in the cortical hemispheres using an experimental model developed by ourselves for investigation of consciousness in the sleep–waking paradigm. This model is based on continuous performance of a monotonous psychomotor test carried out lying down with the eyes closed, which in a 1-h experiment allows observation of several brief episodes of sleep with subsequent spontaneous awakening and recovery of psychomotor test performance. A necessary condition for recovery of activity after spontaneous awakening is the appearance of the EEG α rhythm, and the parameters of this rhythm determine the effectiveness of recovery of the psychomotor test and, thus, achievement of a particular level of consciousness, so this can be regarded as a neurophysiological correlate of the activation of consciousness on awakening. This experimental model for studies of consciousness may be useful for analysis of the neurophysiological mechanisms of its activation in patients with chronic impairments of consciousness and for seeking effective methods for the rehabilitation of such patients.

An Erratum to this paper has been published: https://doi.org/10.1134/S0362119722440013

A study of the sleep-to-wake transition accompanied by therestoration of activity makes it possible to explore the successiveactivation of different levels of consciousness upon awakening. Here,we explored this process using a continuous discrete psychomotortest as an experimental model. The study was aimed to analyze thedynamics of EEG rhythm coupling over the 20-s interval that precedesthe moment of cognitive awakening (the appearance of a pronouncedalpha rhythm). For multi-channel EEG analysis, we used the algorithmof continuous wavelet transform based on Morlet wavelet as a motherwavelet. The amplitude interaction of EEG rhythms (delta, theta,alpha1, alpha 2, beta, and gamma) was assessed using the Kendallcorrelation coefficient. It was shown that the process of awakeningfrom sleep is a prolonged phenomenon with a complex dynamics ofEEG rhythm coupling. Three blocks of such couplings were identified,manifesting themselves differentially as the moment of cognitiveawakening approached. Within the 20–15-s interval before awakening,the block of alpha–beta and alpha–gamma rhythm couplings was predominant,although single delta–theta, theta–alpha1 and beta–gamma couplingswere also present. The next interval (15–5 s) before awakening wascharacterized by joining the block of theta rhythm couplings withfaster rhythms to the already active block of alpha rhythm couplings.The third block of delta rhythm couplings with theta and alpha rhythmsjoined in the 5–0-s interval before awakening.

Studies in healthy adult volunteers with different levels of anxiety addressed the effectiveness of recovery of monotonous activity after brief episodes of daytime sleep. A continuous-discrete psychomotor test was used in which the experimental participants carried out two sequentially alternating tasks: counting to themselves from 1 to 10, accompanied by synchronous pressing of a button with the right hand, and counting to themselves without button-pressing. Subjects’ eyes were closed during the whole experiment. All subjects performed the test correctly before going to sleep. Subjects who started to make errors in the number of button presses and performed the test significantly more slowly after waking showed increases in the spectral power of EEG δ, θ, and α oscillations. These results point to marked signs of sleep inertia in the conditions in which the activity was performed. After waking, groups of subjects performing the task accurately in both experimental situations displayed no changes in the δ, θ, or α1 ranges compared with the beginning of the experiment. This fact, as well as the observation that test performance speed decreased slightly, provides grounds for suggesting that the sequelae of short-term sleep had smaller effects on performance of the psychomotor test in these subjects. We suggest that the decrease in α2 power in the caudal EEG leads reflects activatory processes supporting more effective activity in these conditions. Short-lived daytime sleep had different effects on the effectiveness of recovery of activity in healthy subjects with different anxiety levels. After waking, subjects with elevated anxiety showed greater signs of sleep inertia and performed the psychomotor test task worse than at the beginning of the experiment before going to sleep. The effect of short-term sleep on the effectiveness of test performance was significantly less marked in less anxious subjects.

During daytime sleep, the changes in the spectral characteristics of the EEG during recovery periods of the psychomotor test with spontaneous short-term awakenings were studied in 17 healthy subjects. The test contained two successively alternating tasks: the “silent” counting from 1 to 10, synchronized with the clicks on the button, and only the “silent” count. The monotonous nature of the test leads to a rapid decrease in the level of wakefulness and in most cases causes falling asleep. The appearance of button clicks is a behavioral indicator of the resumption of cognitive processes inhibited during sleep. Situations were compared for a small (2–5) and relatively large (6–10) number of button presses. The onset of button presses is preceded by the appearance of a generalized alpha rhythm, which decreases during psychomotor activity. At the same time, its power was always greater in a situation with longer periods of observed behavioral activity. The cessation of the button presses is accompanied with the return of the alpha activity power to values observed before the awakening. The EEG alpha rhythm at the reduced wakefulness during short-term awakenings apparently characterizes the activation of the thalamo-cortical mechanism, and is required for the motor interaction of the body with the environment. The absence of differences in the frontal areas at the initial stage of performing short-term and longer-term activity (approaching the full cycle of clicks) suggests that during this period they are involved to the same extent, regardless of the number of clicks. These results indirectly confirm that the observed psychomotor activity, even with a small number of clicks, is not automatic and unconscious, but is accompanied by a reduced, fragmented consciousness.

Changes in EEG spectral characteristics during periods of recovery of performance in a psychomotor test during spontaneous short-term periods of waking in daytime sleep were studied in 17 healthy subjects. The test consisted of two sequentially alternating tasks: to count from 1 to 10 silently accompanied by synchronized pressing of a button, and silent counting only. The monotonous nature of the test led to a rapid decline in the level of consciousness and, in most cases, induced falling asleep. Presses serves as a behavioral indicator of the recovery of cognitive processes inhibited during sleep. Situations with small (2–5) and relatively large (6–10) numbers of button presses were compared. The start of pressing was preceded by the appearance of generalized α rhythm, which decreased during performance of psychomotor activity. The power of this rhythm was always greater in longer periods of observed behavioral activity. The end of pressing returned α-power indicators to levels seen before waking. The EEG α rhythm in decreased consciousness during short-term waking evidently characterized the action of the thalamocortical activatory mechanism and was a necessary condition for motor interaction of the body with the external environment. The absence of any differences in the frontal areas at the initial stage on performance of short-lived activity and longer-lasting activity, approaching performance of the complete cycle of presses, suggested that they are involved to the same extent during this period regardless of the number of presses. This result may provide indirect support for the notion that the observed psychomotor activity, even with a small number of presses, is not automatic and unconscious but is accompanied by reduced and fragmented consciousness.

The aim of the study is to identify the features of fast and slow rhythmic components of EEG in preparation for visual identification in students with sleep disorders, compared with the control group of well - sleeping students. Methods. Twenty three (12 of them with poor quality of sleep) students comprised the sample. We studied associations of theta, low-and high - frequency alpha and beta rhythms in the process of listening to the instructions for the activity, in a state of working rest and in pre - tuning to the identification of the emotional expression. Multi-channel EEG was recorded. Distributions of the values of the modulus of the coefficient wavelet transform (CWT) for characterizing the amplitude of the potentials were studied. Pearson correlation coefficients were calculated. Results. Both groups of students showed the connection of almost all studied pairs of rhythms during listening to the instruction. Students with sleep disorders were characterized not only by a lack of communication alpha 1-and beta rhythms, but also theta and beta rhythms during the state of rest after instructions listening. We see the only one significant coupling alpha 1-and beta rhythms (r = - 0,56; P. = 0,048) in students with sleep disorders in the presentation of two faces with different expressions. Students with sleep disorders revealed a significant relationship of alpha 1-and theta rhythms (r = 0,71, P. = 0,006) in the pre-stimulus period at the stage of the experiment, when two identical faces were presented. Summary. 1. Significantly fewer links alpha and theta rhythms with beta rhythm revealed in preparation for visual recognition in students with sleep disorders. 2. Students with sleep disorders in the performance of tasks committed identification errors in the presentation of pairs of faces with different expressions and the same. Whereas students without sleep disorders at presentation of faces with different expression didn't make mistakes of recognition.

We studied the dynamics of cortical potentials in four frequency ranges (8–13, 15–20, 21–40 and 41–60 Hz) upon the presentation in the middle interval of conditioning Go/NoGo stimuli in the cognitive model of facial expression in 4-second intervals between the target and the trigger stimuli (wavelet transform). The patterns of significant induced responses formed in certain cortical areas in each of the hemispheres differed in the groups of subjects depending on the task performance. The effect of both conditioning stimuli on the levels of induced responses is shown depending on the frequency range. In the first ranges, the effect of positive Go stimuli was dominant. The inhibitory NoGo stimulus in the high-frequency range 41–60 Hz had a significantly more pronounced effect on the levels of induced responses, which determined the formation of patterns of significant responses in larger zones of the activated areas. We assume that the process of mutual influence between the functionally different Go and NoGo stimuli in a wide band of EEG components is an important factor determining the interaction of the high-frequency activity with other frequency bands in spatially separated regions, which, in turn, ensures the conditions for human cognitive activity.

In experiments with daytime sleep, according to data obtained from 23 subjects, changes in the spectral characteristics of the EEG in the period preceding the moment of awakening, which was recorded to restore the psychomotor test, were studied. During one short experiment, it can be used to investigate several consecutive episodes: the disappearance of conscious cognitive activity when falling asleep and its resumption upon spontaneous awakening. The study of the characteristics of the EEG before awakening is important for assessing the transients of the sleep-wake cycle, determining the degree of recovery of psychomotor activity upon awakening and the level of the accompanying consciousness. It is shown that the alpha activation observed upon awakening is often preceded by the appearance of K-complexes, of varying degrees of severity, on which low-frequency alpha oscillations are superimposed, which can be regarded as slow sigma spindles. This pattern most likely reflects the action of a universal thalamocortical activating mechanism, the same for both night and daytime sleep, regardless of whether it follows a short-term activation followed by sleep or further begins a cognitive activity.

Interactions of the θ, α, and β EEG rhythms were studied in a set to an emotional facial expression in 30 adult subjects. Electroencephalogram (EEG) data wee analyzed by wavelet transformation in the range 1–35 Hz. The mean and maximum wavelet transformation coefficients (WTC) were computed. Relationships between the β2/α1 and β2/α2 subranges were seen in subjects with erroneous recognition at the set testing stage, as detected using the mean WTC level. The β2/θ rhythm pair showed significant correlation coefficients both for the mean WTC level and the maximum WTC level, and for maximum WTC values in subjects without errors at the set formation stage. New data were obtained supporting the view that the thalamocortical and corticohippocampal systems are involved in supporting the process of recognizing facial expression during set formation and testing, while their interaction may provide a predictor for the success of visual recognition.

На 23 студентах исследовали особенности взаимодействия тета-, альфа- и бета-ритмов при восприятии эмоционального выражения лица. Анализировали отрезки ЭЭГ посредством непрерывного вейвлет-преобразования на основе «материнского» комплексного Morlet-вейвлета в диапазоне 1-35 Гц. Для оценки взаимодействия бета-ритма с тета-, альфа1- и альфа2-ритмами использовали коэффициент корреляции Пирсона. У студентов с нарушениями сна при восприятии разных лиц выявлено отсутствие связей между бета-, альфа- и тета-ритмами. Студенты без нарушений сна продемонстрировали связь альфа-ритма не только с тета-, но и с бета-ритмом. При предъявлении одинаковых лиц у студентов с нарушениями сна отмечена связь бета-ритма с альфа- и с тета-ритмами, тогда как здоровые студенты продемонстрировали связь альфа2- и бета-ритмов. Высказано предположение об активирующей роли бета-ритма при его включении в работу кортикогиппокампального и таламокортикального кругов, что способствовало правильному распознаванию лицевых эмоций.

Two groups of students (with and without learning difficulties) were studied. In the experimental technique used in experiments, an increased load on the working memory by lengthening the interstimulus interval between the conditioning positive (Go) or inhibitory (NoGo) signals and the triggering stimulus was combined with EEG recording. In students with learning difficulties, the evoked synchronization/desynchronization of low-frequency α-oscillations (8–10 Hz) in individual intersimulation intervals was significantly weakened. The hypothesis of the disturbed coordinating mechanism of selective implicit attention with the involvement of the prefrontal cortex in the organization of cognitive activity in students with learning difficulties is discussed and substantiated.