Monotony or mental fatigue occurs during performing low-content and monotonous work, including the work of the operator. It is accompanied by a decrease in the concentration of attention and the speed of its switching, as well as slowing in the processes of perception and motor reactions, which can lead to a loss of vigilance, self-control and the occurrence of drowsiness and, consequently, an increase in the risk of industrial injuries and accidents. In this regard, an urgent task is to develop methods for monitoring the human condition in the process of performing monotonous activities. We investigated the effect of monotony on event-related potentials (ERPs) in the visual cued Go/NoGo test. We analyzed 31-channel EEG data of 25 healthy subjects recorded before and after performing four tests with a total duration of around 1.5 hours, representing the same type of tasks with different instructions and simulating the conditions of monotonous work. After performing four tests, we observe an increase of P2 wave, decrease of the P3 Cue wave and the contingent negative variation (CNV) wave in the Cue condition, as well as the decrease of P300 wave in the NoGo condition. The results obtained in this work are assumed to reflect attenuation in proactive and reactive cognitive control during monotony and allow us to consider the P2, P3 Cue, CNV and P3 NoGo waves as possible candidates for the role of neuromarkers of monotony, which makes it promising to use these indicators in systems for monitoring the human condition during operating work.

The aim of the investigation was to study the features of brain activity when comparing visual stimuli under conditions of delayed motor response. Event-related potentials (ERPs) were studied in 84 healthy subjects in a three-stimulus test, the first two stimuli were a comparison pair, and the third stimulus triggered a motor response. After presentation of the second stimulus ERPs were recorded: a complex of two waves with occipital (Oz, most pronounced in the interval 100–150 ms) and posterior temporal localization (P7, P8, 190–270 ms); negative wave in the frontal regions (Fz, 240–300 ms) and positive wave in the parietal regions (Pz, 270–450 ms). Brain responses differ in amplitude in case of a match and discrepancy of visual stimuli. The article discusses the physiological meaning of these waves and their differences under two conditions.

This study presents a comparison of the effect on EEG electrical activity in the range of infraslow frequencies of two methods: infra-low frequency EEG biofeedback and heart rate variability training. The study involved 17 healthy subjects aged 21 to 50 years with minor symptoms of a physiological or psychological nature, who did not have a history of neurological or psychiatric diseases. To evaluate the results of the training, we analyzed the spectral power of slow EEG oscillations during the performance of the attention test (Visual Go/NoGo), recorded before and after twenty sessions of biofeedback. Both the subjective assessment of the physiological and psychological state and the results of the visual test showed more pronounced positive changes under the influence of EEG biofeedback compared to the cases of heart rate variability training. A significant increase in the amplitudes of oscillations in the infraslow EEG range was observed only after EEG biofeedback.

ADHD is a heterogeneous neurodevelopmental disorder associated with dysfunctions in several brain systems. Objective markers of brain dysfunction for clinical assessment are lacking. Many studies applying electroencephalography (EEG) and neuropsychological tests find significant differences between ADHD and controls, but the effect sizes (ES) are often too small for diagnostic purposes. This study aimed to compute a diagnostic index for ADHD by combining behavioral test scores from a cued visual go/no-go task and Event Related Potentials (ERPs). Sixty-one children (age 9-12 years) diagnosed with ADHD and 69 age- and gender-matched typically developing children (TDC) underwent EEG-recording while tested on a go/no-go task. Based on comparisons of ERP group-means and task-performance, variables that differed significantly between the groups with at least moderate ES were converted to a five points percentile scale and multiplied by the ES of the variable. The sum-scores of the variables constituted the diagnostic index. The index discriminated significantly between patients and TDC with a large ES. This index was applied to an independent sample (20 ADHD, 21 TDC), distinguishing the groups with an even larger ES. The diagnostic index described has the potential to support assessment. Further research establishing diagnostic indexes for differential diagnoses is needed.

Infra-low frequency neurofeedback (ILF NF) has been proposed as an alternative or complementary treatment method. Previous studies have reported a good effect of ILF training on the subjective perception of positive psychological changes after training. Here we study whether the objective physiological parameters reflecting the brain function also change under the influence of ILF NF. Eight participants 21–50 years of age with no history of neurological or psychiatric diseases, but reporting about some physiological or psychological complaints, performed 20 sessions of infra-low frequency neurofeedback training. EEG in visual Go/NoGo test was recorded before the course of Neurofeedback and after its completion. The spectral power of slow EEG oscillations in the post-training recording was compared with the pretraining baseline. After 20 sessions of ILF training, the pattern of ILF activity at rest changed dramatically. The main difference was an increase in the amplitude of the ILF activity up to 0.3–1.0 mV in all recording sites. These results indicate that ILF training modified the baseline brain state in each case. Furthermore, after completion of 20 NFB sessions, all participants indicated improvement of their state. Most of them noticed a decrease of inner tension and reactivity to stressful factors. Further, they reported on stability of mood, improved body and space awareness, increase of energy level and of cognitive performance. Along with this remission of the clinical complaints, significant increase of spectral power in 0–0.5 Hz frequency band was observed in all eight participants in the post-training EEG patterns compared to the pretraining EEG. Our study has shown the changes in the amplitude distribution within the ILF spectral range in all participants that seems to be induced by the ILF training. In other words, the ILF training leads to the changes of the functional state of the brain. We suggest that the modification of the baseline ILF EEG pattern may reflect the normalization in the metabolic balance in the brain tissue and increasing efficiency of compensatory mechanisms in the stress regulation systems.

This study aimed to analyze positron emission tomography with 18F-fluorodeoxyglucose data and event-related potentials in the Go/NoGo paradigm in patients with Parkinson's disease with and without cognitive impairment. In the group of cognitively impaired patients, glucose metabolism was decreased in the frontal, parietal, cingulate and posterior temporal cortex. Correlations were found between the cognitive scores and cerebral glucose metabolism in those areas. Event-related potentials analysis revealed a decrease in the amplitude of the late positive wave (P300 NoGo wave) in the group of cognitively impaired patients. The analysis revealed that decline in amplitude of P300 wave was accompanied by decreased glucose metabolism in several cortical areas associated with cognitive impairment in Parkinson's disease. Correlations of glucose metabolism in these areas with event-related potentials amplitude in the NoGo condition confirm the important role of executive functions disorders in the pathogenesis of cognitive impairment in Parkinson's disease.

The aim of this study was to evaluate dysregulation of gene expression associated with the cellular stress response in a patient with a post-"warning stroke" depressive disorder confirmed by the presence of a neurophysiological neuromarker through the use of quantitative EEG and event-related potentials. The patient was tested for seven genes associated with the stress reaction: HSPA1A, HSPB1, IL6, IL10, CRP, and HSF-1 along with NF-κB, compared to gene expression in health controls. A 54-year-old patient with a past history of schizophrenia (at the age of 20), and of transient ischemic attack (at the age of 53) and depressive disorder confirmed by functional, cognitive, emotional, and affectional diagnostics underwent additional testing for expression of the genes associated with stress response. The expression of genes coding for heat shock protein (HSPA1A, HSPB1), interleukins (IL6, IL10), and C-reactive protein was tested along with factors that regulate their expression. The results of the tests conducted on this patient were compared with 42 healthy control subjects. Diagnostic testing revealed upregulation in expression of these genes, presenting as increased expression of the target genes and of the regulatory genes. A post-"warning stroke" depressive disorder appears to be associated with overexpression of the genes coding for HSP and interleukins. Further research on larger groups of people may provide grounds for treatment modification.

Current research suggests that associations between headache conditions (migraine, tension) and imbalances in the autonomic nervous system (ANS) are due to stress-related dysregulation in the activity of the parasympathetic-sympathetic branches. Mindfulness meditation has demonstrated effectiveness in reducing pain-related distress, and in enhancing heart rate variability—a vagal-mediated marker of ANS balance. This study examined HRV during cognitive stress and mindfulness meditation in individuals with migraine and tension headaches.Undergraduate students with tension and migraine headaches (n = 36) and headache-free students (n = 39) were recruited for an experiment involving HRV measurement during baseline, cognitive stress-induction, and after randomization to post-stress conditions of audio-guided mindfulness meditation practice (MMP) or mindfulness meditation description (MMD). HRV was derived using electrocardiograms as the absolute power in the high frequency bandwidth (ms2). A three-way ANOVA tested the effects of Group (headache vs. headache-free), Phase (baseline, stress, & post-stress), and Condition (MMP vs. MMD) on HRV.ANOVA revealed a significant three-way interaction. Simple effects tests indicated: 1) HRV increased significantly from stress to MMP for headache and headache-free groups (p < 0.001), 2) significantly greater HRV for headache (p < 0.001) and headache-free (p < 0.05) groups during MMP compared to MMD, and 3) significantly lower HRV in the headache vs. headache-free group during the post-stress MMD condition (p < 0.05).Results suggest mindfulness practice can promote effective heart rate regulation, and thereby promote effective recovery after a stressful event for individuals with headache conditions. Moreover, headache conditions may be associated with dysregulated stress recovery, thus more research is needed on the cardiovascular health and stress resilience of headache sufferers.

The article analyzes event-related potentials in the Go/NoGo test of patients with schizophrenia and schizotypal personality disorder in relation to healthy subjects. Differences identified in the group of patients with schizophrenia are consistent with previous studies and indicate disruption in processes associated with different stages of visual information processing and executive functions. Specific features of brain activity in patients with schizotypal personality disorder were significantly less pronounced and presumably pointed to changes in the processes of attention redistribution and action monitoring. The results agree well with the clinical symptoms of schizophrenia and schizotypal personality disorder, so that this technique can be considered a possible additional diagnostic criterion for these disorders.

The article deals with recent research in the field of fundamental knowledge about the mechanisms of information processing in the human brain for the diagnosis of mental disorders performed in the laboratory of neurobiology for action programming of the Bechtereva Institute of the Human Brain of the Russian Academy of Sciences. These studies were connected with the analysis of functional components for cognitive event-related potentials (ERPs) obtained under various behavioral conditions. The main goal of this fundamental approach is the decomposition of multi-channel ERPs into functionally different components. These components are generated in various cortical areas, have different temporal dynamics, and reflect a variety of mental operations. The main methodology we used is the independent component analysis, applied to a large set of ERPs (from hundreds of people) obtained by varying functional conditions in the psychological test. In particular, components related to psychological processes, such as the comparison of sensory signals with a trace in working memory, inhibition of current activity, and monitoring of conflict, were identified in the GO/NOGO test. In the European project, a normative database was constructed for the components described above, and this allowed us to compare the data obtained from large groups of patients (including patients with attention deficit disorder, schizophrenia, obsessive disorders, depression, autism, dyslexia, brain trauma, and dementia) with the healthy subjects. This article presents data from patients with a diagnosis of attention deficit disorder and schizophrenia.

Background: Schizophrenic patients suffer from cognitive and attentional deficits, particularly from failure of executive control functions.Methods: This study investigated the cortical organization of executive control in schizophrenic patients and healthy control subjects using event-related potentials (ERPs). Event-related potentials were collected while subjects performed an auditory Go/NoGo task that required response inhibition. To exclude stimulus discriminability and early stimulus processing to confound results, stimuli were adjusted to the subject’s individual discrimination ability and were presented in a simple and a difficult version.Results: Schizophrenic patients performed similar to control subjects in the Go condition but worse than control subjects in the NoGo condition that required response inhibition. Event-related potentials revealed the neurophysiological substrate of this dysfunction. In the Go conditions, both healthy control subjects and schizophrenic patients showed the same voltage pattern. In the NoGo condition, control subjects and patients showed similar cortical activation only during early processing (N2 time window). However, in later stages of processing (P3 time window), healthy subjects showed left lateralization of ERPs over frontal areas while schizophrenic patients did not.Conclusions: We conclude that schizophrenic patients exhibit deficient processing in a neuronal network, including left frontal areas, that is involved in later stages of executive control function.

Eighty-six children (ages 9-14) with attention deficit hyperactivity disorder (ADHD) participated in this study. Event-related potentials (ERPs) were recorded in auditory GO/NOGO task before and after 15-22 sessions of EEG biofeedback. Each session consisted of 20 min of enhancing the ratio of the EEG power in 15-18 Hz band to the EEG power in the rest of spectrum, and 7-10 min of enhancing of the ratio of the EEG power in 12-15 Hz to the EEG power in the rest of spectrum with C3-Fz electrodes' placements for the first protocol and C4-Pz for the second protocol. On the basis of quality of performance during training sessions, the patients were divided into two groups: good performers and bad performers. ERPs of good performers to GO and NOGO cues gained positive components evoked within 180-420 ms latency. At the same time, no statistically significant differences between pre- and post-training ERPs were observed for bad performers. The ERP differences between post- and pretreatment conditions for good performers were distributed over frontal-central areas and appear to reflect an activation of frontal cortical areas associated with beta training.