EEG-correlates of work efficiency level among young persons with stress-induced bruxism

Purpose of the study. To establish the relationship between neurophysiological status and the level of efficiency in young people with bruxism.Materials and methods. Two groups of 64 and 53 subjects (males and females) aged 20–35 years old with bruxism and non-bruxers were formed according to questionnaire results and physical examination. The level of efficiency was assessed by the results of sensorimotor tracking of a moving object (the ‘Smile’ model). Spectral analysis was performed for evaluation of the baseline electroencephalograms. Microsoft Excel and Statistica 10.0 programs were used for statistical data processing.Results. The level of efficiency was statistically significantly lower in the hardest test of Smile model among the individuals with bruxism (p < 0.05). The bruxers also demonstrated a significantly lower dominant frequency and maximum amplitude of alpha-rhythm (p < 0.05), and significantly higher dominant frequency of beta2 rhythm (p < 0.05). The dominant frequency and the maximum amplitude of the alpha-rhythm are parameters corresponding to significant coefficients of the regression analysis. A negative relationship was found between the degree of error during sensorimotor tracking and the frequency and amplitude of alpha-rhythm.Conclusion. Regression models present the relationship between the level of efficiency and the alpha-rhythm severity. The regression equations make it possible to determine the functional state of the subject using an electroencephalogram.

Power spectrum of electroencephalogram: Mistakes and Practical Application

In this lecture, the state of the practical use of spectral analysis of EEG is analyzed in detail. The author focuses on the reasons for the slow introduction of spectral analysis into everyday practice and identifies ways to overcome this deficiency. The reason for the need to master this useful analysis technique has been substantiated. The algorithm for performing spectral analysis of EEG in practice, both at the stage of processing and at the stage of data interpretation, is presented in detail. In the lecture, the author outlined the features of the options for the spatial organization of the alpha rhythm and their relationship with the characteristics of the human psyche. One of the reasons that hinders the use of EEG spectral analysis in practice is the lag of the software of electroencephalographic computer systems of leading manufacturers from modern requirements of the time.

Quantitative characteristics of the alpha-rhythm of the electroencephalogram in depressive disorders

The aim of research was to study the quantitative characteristics of the alpha rhythm in patients with depressive disorders. Material and methods. The study sample consisted of patients who were treated at the clinic of the Research Institute of Mental Health (department of affective states) Tomsk NIMC. A total of 84 patients (67 women, 17 men) aged 20 to 60 years with mood disorders in the framework of a depressive episode, recurrent depressive disorder and dysthymia were examined. An electroencephalogram was recorded at rest with closed and open eyes. The values of the absolute spectral power of the alpha rhythm, the parameters of the microstructure of the alpha spindle were analyzed and the reactivity index (the Berger effect) was calculated. Results. With open eyes, the spectral power of the alpha rhythm was statistically significantly higher in patients with depressive disorders in the Fp1 (p=0.041), F4 (p=0.042), F7 (p=0.046) and T4 (p=0.047) leads compared to the control. Also, in patients with depressive disorders, a predominantly low-amplitude alpha rhythm was recorded (53.6% vs. 26.7%, p=0.006). The degree of alpha-rhythm depression in the posterior temporal leads T5 (p=0.012) and T6 (p=0.006) was statistically significantly less pronounced in patients with depressive disorders compared to the control group of healthy individuals. Conclusion. The detected changes indirectly indicate a decrease in the oscillatory activity of brain processes in depressive disorders.

Bioelectric activity of the brain in 3-4 years old children in eyes-open resting state

Background. Electroencephalography is the main technique for assessing the functional state of the brain. Indications for EEG are diagnosis of paroxysmal states, prediction of the outcome of a pathological state, evaluation of bioelectrical activity if brain death is suspected. Up to 90 % of the native EEG in calm wakefulness in healthy individuals is occupied by “alpha activity”. In children in active wakefulness, the EEG pattern depends to a great extent on their age.Objective. The aim of the work was to assess EEG parameters in children aged 3–4 years in eyes-open resting state. Design and methods. 31 healthy participants aged 3–4 years were enrolled. EEG was registered for 30 minutes in a state of passive wakefulness in the supine position with open eyes. Average values of the power of the spectra for the alpha-rhythm, delta-rhythm and theta-rhythm in the frontal and temporal leads, as well as the ratio of the average power of alpha/theta and alpha/delta rhythms in the frontal and temporal leads were calculated.Results. Average power of the alpha-rhythm was significantly higher over the right frontal lobe than over the right frontal-temporal area, as well as average amplitude of it was significantly higher in F3-A1 than F7-A1, F4-A2 than F8-A2, which is associated with the articulatory praxis. Average alpha-rhythm power was significantly higher in T5-A1 than T3-A1 and T6-A2 than T4-A2, which corresponds to the recognition and naming of objects optically. Significant differences according to the total average power of the alpha- and theta-rhythms above the frontal and frontal-temporal regions reflect the relationship between the frontal cortex temporal lobes and the premotor zones, i.e. arcuate bundle, responsible for the “speech system”.Conclusion. The identified patterns can reflect the characteristics of the state of active wakefulness in a 3–4-year-old child and can be used for comparison in the future (both in the course of behavioral experiments and observation of patients with certain pathological processes).

The meaning of EEG indicators of loss of consciousness during anaesthesia and coma.

Raw EEG changes correlate well with the effects of anaesthetics on arousal. The purpose ofthe present paper is to analyse the significance of the EEG spectrograph. The alpha rhythm isa signature of the unconscious and according to the MAB hypothesis (Monoaminergic-Acetylcholinergic Balance) is an index of increased relative inhibitory muscarinic effects onmonoaminergic modulated conscious networks. The source of alpha rhythms varies, as doesthe type of unconscious information: from classical occipital alpha during resting state witheyes closed where no external visual information is processed, to states of unconsciousanaesthesia where alpha shifts to fronto-parietal networks. These are spontaneous oscillatorynetwork responses and the effects of GABA agonist anaesthetics increase the amplitude ofthese intrinsic rhythms. The hypothesis states that the concurrent presence of sustained deltaoscillations and alpha spindles signifies suppressed unconscious and conscious responsesrespectively, and permit neither implicit nor explicit cognition nor recollections. Further, themodel will be used to interpret EEG changes associated with more atypical anaesthetics andprovide reasons for the related cognitive effects. This will be based on the agents’pharmacological profiles and how they interact with these dual neuromodulatory systems.Evidence will also be drawn from EEG states associated with pathophysiology in coma andepilepsy. The pharmacological interpretation of EEG makes predictions of awareness indisorders of consciousness. The difficult circumstances of behaviourally inadequateindicators refers to situations of minimally conscious and in particular, vegetative stateswhere decision making is fraught with uncertainty.

Aperiodic EEG activity masks the dynamics of neural oscillations during loss of consciousness from propofol

EEGs are known to provide biomarkers for consciousness. Although EEG correlates of loss of consciousness (LOC) are often ascribed to changes in neural synchrony, mounting evidence suggests that some changes result from asynchronous neural activity. By combining EEG recordings of humans undergoing propofol administration with biophysical modelling, we present here a principled decomposition of EEG changes during LOC into synchronous and asynchronous sources. Our results reveal that IPSP decay rate and mean spike rate shape aperiodic EEG features, and that propofol's effects on these parameters largely explain the changes in EEG spectra following propofol infusion. We further show that traditional spectral EEG analysis likely conflates these effects with changes in rhythmic activity, thereby masking the true dynamics of neural synchrony. We conclude that the well-documented propofol-induced alpha rhythm in fact appears before LOC, and that the moment of LOC is uniquely correlated with the sudden appearance of a delta rhythm.

Hygienic Assessment of Digital Writing: A Bio-Cybernetic Approach. Report I

Background: Introduction of digital technologies into the educational process involves the widespread use of keyboard typing and spending less time handwriting. At the same time, studies in the field of physiology and hygiene of handwriting show its importance for the development and formation of brain functions in children in the learning process. Potential risks for child development associated with regular typing and rare handwriting require proper hygienic assessment of the former. Yet, the lack of a scientifically based methodological approach is a strong limitation for such studies. Objective: To develop a methodological approach and conduct a pilot study on hygienic assessment of digital writing based on a bio-cybernetic analysis of the bioelectrical activity of the brain. Materials and methods: To arrange and conduct the research, we developed an algorithm based on a comparative analysis of the bioelectrical activity of the brain during typing and handwriting. Scalp electrodes were applied according to the International 10–20 system. EEG registration was carried out using a Neuro-KM computer-aided electroencephalograph by Statokin, Russia, with a Brainsys software for spectral-coherent and statistical analysis of EEG. The software allowed us to estimate the topography of the absolute power of the alpha rhythm in a resting state, during handwriting and typing, and the intrahemispheric and interhemispheric coherence of the alpha rhythm. Results: We established that the power of vibrations in the alpha range during digital and handwriting decreased compared to the resting state. Such a decrease reflecting activation of the cortex was noted in a more extensive area during handwriting. Typing decreased alpha waves only in the motor and sensorimotor areas of the brain. Compared to the resting state, handwriting significantly increased interaction between all areas of the cortex inside both hemispheres while typing did that in one hemisphere only. Conclusion: Our findings indicate that handwriting is provided by a more complex system of activation and interaction of areas of the cerebral cortex than typing. The developed algorithm can be used for further research on digital writing.

Neural rhythmic underpinnings of intergroup bias: implications for peace-building attitudes and dialogue

Intergroup bias is a ubiquitous socio-cognitive phenomenon that, while sustaining human dependence on group living, often leads to prejudice, inequity, and violence; yet, its neural underpinnings remain unclear. Framed within the Israeli–Palestinian conflict and targeting youth, this study utilized magnetoencephalography to describe intrinsic neural oscillatory processes that represent the intergroup bias and may link with engagement in peacemaking in order to shed further light on the neural mechanisms underpinning intergroup conflict. Across the oscillatory spectrum, from very low to very high frequency bands, the only rhythm found to underlie the intergroup bias was the alpha rhythm. Alpha rhythm was continuously activated across the task and integrated a rapid perceptual component in the occipital cortex with a top-down cognitive-control component in the medial cingulate cortex. These components were distinctly associated with the real-life intergroup dialogue style and expressed attitudes that promote active engagement in peacemaking. Our findings suggest that the cortical alpha rhythm plays a crucial role in sustaining intergroup bias and addresses its impact on concrete intergroup experiences. The results highlight the need to provide opportunities for active peace-building dialogue to youth reared amidst intractable conflicts.