Power Of Alpha Rhythm Research Articles

Enhancing motor skill learning through multiple sessions of online high-definition transcranial direct current stimulation in healthy adults: insights from EEG power spectrum.

The purpose of this study was to evaluate the influence of high-definition transcranial direct current stimulation (HD-tDCS) on finger motor skill acquisition. Thirty-one healthy adult males were randomly assigned to one of three groups: online HD-tDCS (administered during motor skill learning), offline HD-tDCS (delivered before motor skill learning), and a sham group. Participants engaged in a visual isometric pinch task for three consecutive days. Overall motor skill learning and speed-accuracy tradeoff function were used to evaluate the efficacy of tDCS. Electroencephalography was recorded and power spectral density was calculated. Both online and offline HD-tDCS total motor skill acquisition was significantly higher than the sham group (P < 0.001 and P < 0.05, respectively). Motor skill acquisition in the online group was higher than offline (P = 0.132, Cohen's d =1.46). Speed-accuracy tradeoff function in the online group was higher than both offline and sham groups in the post-test. The online group exhibited significantly lower electroencephalography activity in the frontal, fronto-central, and centro-parietal alpha band regions compared to the sham (P < 0.05). The findings suggest that HD-tDCS application can boost finger motor skill acquisition, with online HD-tDCS displaying superior facilitation. Furthermore, online HD-tDCS reduces the power of alpha rhythms during motor skill execution, enhancing information processing and skill learning efficiency.

Abnormalities in the absolute power of Delta and Alpha rhythms in the frontal lobe of patients suffering from psychosomatic disorders.

Psychosomatic disorders (somatic symptom disorder - SSD) constitute a heterogeneous group of medical conditions characterized by somatic symptoms without explained somatic causes. Due to the complexity of symptoms, they present a significant medical, social and economic challenge, and diagnosing and treating these disorders remains a substantial clinical challenge. The aim of the conducted research was an attempt to identify characteristic patterns in the surface-level brain bioelectrical activity of individuals experiencing psychosomatic disorders. The obtained results may contribute to understanding the pathomechanism of these disorders and developing objective methods for diagnosis and differentiation of functional dysfunctions. The study involved a group of 49 individuals: 30 patients with somatic symptom disorder (SSD) and 19 individuals in the control group. Resting-state EEG signals were recorded from the subjects under two experimental conditions (eyes open, eyes closed). The recorded signals underwent quantitative EEG (QEEG) analysis followed by statistical analysis. EEG signal analysis revealed statistical differences between the studied groups in terms of absolute power in the Alpha band (8-12 Hz) in frontal areas (electrodes F3, Fz, F4) under eyes-open conditions, as well as in the Delta band (1-4 Hz) in the right frontal area (electrode F4) under eyes-closed conditions. Similar changes were not observed in the Beta (12-25 Hz) or High Beta (25-30 Hz) bands. The detected abnormalities in the surface-level brain bioelectrical activity may indicate potential disturbances in the reception and interpretation of visceral sensations in patients with psychosomatic disorders. The lack of differences in higher frequencies could be helpful in the differential diagnosis between these disorders and other anxiety disorders where psychosomatic symptoms are observed. The obtained results could also be useful in planning protocols involving various neurotherapeutic methods.

Особенности мозговой активности хоккеистов и борцов вольного стиля в задаче по отбиванию шайб в условиях виртуальной реальности

Background. Very scarce works are devoted to the study of hockey players' brain activity, which is connected, among other things, with the large amount of motor activity in athletes and the complexity of EEG registration. Objective. The aim of the study was to investigate electroencephalographic markers (in alpha, beta, and theta EEG bands) during a puck kicking task of varying difficulty under virtual reality conditions in ice hockey players compared to freestyle wrestlers. Methods. The previously developed VR-PACE technology was used for the study, which allows practicing puck reflection skills in hockey in a virtual scene. In the study, pucks were presented in blocks (five blocks in total), the difficulty increased from block 1 to block 4, in block 5 the subjects only observed the pucks. EEG recordings were made using a wireless electroencephalograph BrainScanner V3.1 (research edition) by “NeuroDrive” throughout the entire task, analyzed by 20-second segments in each block and in each of the backgrounds (before and after). Twenty-two male subjects (average age=20, SD=2.4 years) participated in the study. Results. The results showed significant differences between the groups, as well as significant within-group differences between the “before” and “after” conditions of the experiment in terms of the Individual Alpha Frequency (IAF), as well as the average and total power of theta, alpha, and beta rhythms. The overall trend in both groups is similar (after the experiment, there is a decrease in IAF, an increase in alpha rhythm power in central and parietal electrodes, and a decrease in occipital electrodes; a decrease in theta rhythm power in frontal and occipital electrodes; and a decrease in beta rhythm across all electrodes). However, the hockey group exhibits significantly more pronounced shifts in EEG, indicating greater alertness and attention (higher powers of theta, alpha, and beta rhythms both before and after the experiment), as well as greater relaxation (higher power of mu rhythm after the experiment). Conclusions. The study examined the electroencephalographic correlates (IAF, power in the alpha, beta, and theta frequency bands of EEG) in hockey players and freestyle wrestlers while performing a task of deflecting a puck in virtual reality (VR). The dynamics of the EEG indicators indicate more efficient brain function in hockey players when performing the puck reflection task in a virtual reality setting, confirming the hypothesis of neural efficiency.

ELECTROENCEPHALOGRAPHIC MARKERS OF CNS FUNCTIONAL STATE IN SPORT

All over the world, sports professionals are interested in attracting new technologies to work-out sessions to increase sportsmanship. Literature reveals that EEG markers of cognitive function dynamics, sensorimotor integration, and psychological stability are important in assessing the functional state of athletes. In addition to a high level of physical fitness, elite athletes develop cognitive skills specific to a particular sport. Besides they demonstrate high sensorimotor integration, improved attention, perception and information processing and other characteristics ensuring high performance. The review systematically analyzes publications devoted to the correlation between physical activity and CNS functional state. It is established that indicators of EEG alpha rhythm power and frequency are significant neurophysiological markers of cognitive function state. These indicators contribute much to studying high- and low-intensity physical activity.&#x0D; The authors analyzed such databases as Medline, Web of Science, Scopus, Pubmed, Cochrane, Embase, Google Scholar, and eLIBRARY.

Features of bioelectric brain activity in people with different level of situational anxiety when performing non-verbal tasks

The purpose of the study: to analyze the parameters of the electroencephalogram in individuals with different levels of anxiety when performing non-verbal tasks.Object and methods. The study was conducted on 20 female students, aged 18 to 22 years. All studies were carried out on a voluntary basis, confirmed in writing, in compliance with bioethical standards governing the conduct of observations on humans. The level of situational anxiety was determined using the Spielberg-Khanin test.The spectral power of the electroencephalogram rhythms was recorded using the NVX 36 digital DC EEG neurovisor using a cap with a set of electrodes that were placed on the head of the subjects according to the international 10–20 system. The EEG recording lasted 1–2 minutes before and during the performance of nonverbal tasks. As non-verbal tasks, the subjects were asked to complete the Portsus maze test and the Cattell intellectual test. The results obtained were statistically processed. Differences were considered statistically significant at p &lt; 0.05. All data obtained are presented as arithmetic means ± standard errors of the mean, as well as changes in average values in %.Research results. It was found that the dynamics of EEG parameters in the performance of nonverbal tasks in students depends on the level of their situational anxiety. In persons with a low level of situational anxiety, when performing nonverbal tasks, an increase in the spectral power of the EEG parameters of beta2 and gamma waves in the frontal, parietal, occipital, and central leads is observed.In subjects with an average level of anxiety in the conditions of performing non-verbal tasks, the EEG parameters of beta2 and gamma waves in the frontal, occipital, and parietal leads noticeably increased. Persons with a high level of anxiety are characterized by an increase in the spectral power of alpha, beta2 and gamma rhythms in the frontal, central, parietal and occipital leads.

DYNAMICS OF THE PARIETAL-OCCIPITAL ALPHA RHYTHM ACTIVITY DURING COMPARISON OF VISUAL STIMULI DURATIONS

This research is aimed at studying the dynamics of the parietal-occipital alpha rhythm in its connection with the process of stimuli duration comparison. EEG study was conducted in which participants (n = 48) were asked to compare pairs of visual stimuli of different durations ranging from 3.2 to 6.4 s. The time-frequency analysis of the EEG was carried out in the range of 8–12 Hz. The power of alpha rhythm increases from the stimulus onset to the middle of its presentation, but then its dynamic depends on the stimulus duration: it further increases for short durations (3.2, 3.6, 4.0 s), stays the same for middle durations (4.4, 4.8, 5.2 s) and decreases for long durations (5.6, 6.0, 6.4 s). The relative decrease of alpha power for long stimuli in relation to the short ones was related to subjective perception of time. The results are discussed from the point of view of the “dual klepsydra” model: it is assumed that alpha rhythm acts as an electrophysiological correlate of the functioning of “neural accumulators” associated with the subjective passage of time.

EEG Frontal Asymmetry in Unipolar and Bipolar Depression

Background: given the similarity of clinical manifestations of depressive disorder and depressive episodes within the framework of bipolar affective disorder, diagnostic errors are inevitable. Both overdiagnosis and underdiagnosis of bipolar affective disorder are too common, and it may take several years to establish a correct diagnosis. Despite the fact that it is impossible to completely eliminate diagnostic errors, it is important to reduce their likelihood by better understanding diagnostic criteria.The aim of this study was to study the indicators of frontal EEG asymmetry in patients with unipolar and bipolar depression, as well as to identify possible correlations with the severity of clinical symptoms. Patients and methods: we examined 30 patients with affective disorder in the framework of a single depressive episode or recurrent depressive disorder and 30 patients with bipolar affective disorder, the current episode of mild or moderate depression. The bioelectric activity of the brain was recorded and analyzed with the calculation of the spectral power of beta and alpha rhythm in the frontal cortex and the beta/alpha ratio was calculated.Results: it was found that patients with bipolar affective disorder had left-sided frontal asymmetry, the beta/alpha ratio was lower on the right than on the left (0.57 [0.41; 0.87] vs. 0.67 [0.43; 1.08], p = 0.007), while patients with unipolar depression had a bilateral pattern of frontal beta/alpha ratio (0.67 [0.45; 1.01] vs. 0.69 [0.45; 0.98], p = 0.441). Statistically significant negative associations were also found between the beta/alpha ratio in the right leads in patients with bipolar affective disorder and the duration of the disease (rs=–0.419, p=0.033).Conclusion: the study clearly showed that quantitative EEG indicators can be used as an additional tool for differentiating bipolar and unipolar depression.

Fast channel selection method using modified camel travelling behavior algorithm

Brain computer interface (BCI) is a protocol to communicate between the human brain and a device or application using brain signals. These signals translated to useful commands by using features extraction and classification. The most widely used features is the power of alpha and beta rhythms. This type of features gives only 70% of classification accuracy without any extra processing using fixed channels to read the signals. Because the distribution of the power in the brain is not a standard for all people, each one has his own brain power map. A selection algorithm is used to find the best channels that could generate higher power than the fixed ones. Modified camel travelling behavior algorithm is used to select the channels that used to extract the power of alpha and beta bands of motor imagery signals. This algorithm is faster to find the best set of channels, and obtain classification accuracy more than 95% using support vector machine classifier.

Psychoemotional state and bioelectrical brain activity in patients of different ages with metabolic syndrome after COVID-19

The aim of this study was to find out the impact of COVID-19 infection on the psycho-emotional state and bioelectrical brain activity in persons of different ages with metabolic syndrome. Material and methods. We examined 53 people who were divided into groups depending on age (40–59 years and 60 years and older) and status with regard to COVID-19 infection (contracted, not contracted). Patients had metabolic syndrome (ATP III), underwent comprehensive clinical and laboratory examinations, electroencephalography (an 18-channel electroencephalograph Nihon Kohden, Japan) and answered the Hospital Anxiety and Depression Scale (HADS) questionnaire. Results. Symptoms of anxiety or depression after COVID-19 were found in both age groups of MS. Anxiety symptoms were more often found in the group of 60 years and older. At the same time, subclinical anxiety was noted in persons of 60 years and older, while clinical anxiety – in middle-aged individuals. The latter also showed a trend towards an increase in clinically evident depression after COVID-19. Persons after COVID-19 with symptoms of anxiety or depression (according to the HADS scale) demonstrated changes in the frequency-amplitude indicators of the electroencephalogram (EEG) characterized by a power increase in the range of theta rhythm and accompanied by subclinical and clinical manifestations of depression. About 80 % of people who did not suffer from COVID-19 had normal EEG since 9 Hz alpha rhythm power was registered. In patients after COVID-19, there was a redistribution of alpha-rhythm power range: an increase in the ranges of alpha-1 rhythm and decrease in alpha-2 rhythm power as well as an increase in the delta and theta rhythm power range. Conclusions. 1–3 months following the acute period of COVID-19, the frequency of depression is 3 times higher in middle-aged patients with metabolic syndrome. In elderly patients with metabolic syndrome after COVID-19, anxiety is predominantly diagnosed – almost in every second. These manifestations of anxiety and depression are accompanied by disorganization of the bioelectrical brain activity.

THETA AND ALPHA BANDS SPECTRAL POWER OF RESTING-STATE EEG IN GROUPS WITH DIFFERENT EFFICIENCY OF JOINT ACTIVITY IN DIADS

The aim of the study was to compare the spectral characteristics of theta and alpha frequency bands of the resting-state EEG between groups of subjects with different performance of subsequent joint sensorimotor activity in dyads. The study involved 26 men who, in 13 pairs, performed “Columns” trainings with biofeedback from EMG signals from the flexor muscles of the leading hand. According to their performance, the subjects of each pair were assigned to one of 2 groups: “winners” or “losers”. A higher spectral power of the theta rhythm of the EEG with closed eyes was found in the group of “losers” in comparison with the group of “winners” in the frontal, central and temporal zones of the cortex. The “winners” showed a higher level of spectral power of the EEG alpha rhythm with the eyes closed, especially in the alpha-2 frequency range in all 8 zones. The effectiveness of individual and joint training correlated negatively with the theta power and positively with the power of the EEG alpha rhythms in the closed-eyed state.

The Effect of Lifting-and-Thrusting Laser Acupuncture on Electrodermal Activity of Acupoints, Pulse Characteristics, and Brainwave.

Acupuncture has been shown as an effective traditional Chinese medicine treatment method, especially for pain relief. Recently, laser acupuncture is becoming increasingly popular, thanks to its noninvasive and painless nature and effectiveness in treating diseases, proven by many studies (for example, some previous studies showed that low-power laser stimulation is able to increase the power of alpha rhythms and theta waves). In our prior work, we developed a novel laser acupuncture model that emulates lifting-and-thrusting operation commonly used in traditional needle acupuncture and showed its benefit in improving cardiac output and peripheral circulation. By extending our previous studies, in this work, we perform extensive experiments to understand the effect of such a system on electrodermal activity (EDA) of acupoints, pulse characteristics, and brainwave, to further verify its efficacy. In particular, we found that laser stimulation could cause significant changes in EDA of acupoints, pulse amplitude, pulse-rate-variability (PRV), and acupoint conductance, as a function of laser power and stimulation time. In addition, laser acupuncture with the lifting-and-thrusting operation has more significant effect on increasing the power of alpha and theta frequency bands as compared to laser acupuncture without the lifting-and-thrusting operation. Finally, given sufficient stimulation time (e.g., > 20 min), the performance of a low-powered laser acupuncture with the lifting-and-thrusting operation could be comparable to that of traditional needle acupuncture.

Effect of Carotid Stenosis Severity on Patterns of Brain Activity in Patients after Cardiac Surgery

Background: The negative effects of high-grade carotid stenosis on the brain are widely known. However, there are still insufficient data on the brain state in patients with small carotid stenosis and after isolated or combined coronary and carotid surgery. This EEG-based study aimed to analyze the effect of carotid stenosis severity on associated brain activity changes and the neurophysiological test results in patients undergoing coronary artery bypass grafting (CABG) with or without carotid endarterectomy (CEA). Methods: One hundred and forty cardiac surgery patients underwent a clinical and neuropsychological examination and a multichannel EEG before surgery and 7–10 days after surgery. Results: The patients with CA stenoses of less than 50% demonstrated higher values of theta2- and alpha-rhythm power compared to the patients without CA stenoses both before and after CABG. In addition, the patients who underwent right-sided CABG+CEA had generalized EEG “slowdown” compared with isolated CABG and left-sided CABG+CEA patients. Conclusions: The on-pump cardiac surgery accompanied by specific re-arrangements of frequency–spatial patterns of electrical brain activity are dependent on the degree of carotid stenoses. The information obtained can be used to optimize the process of preoperative and postoperative management, as well as the search for neuroprotection and safe surgical strategies for this category of patients.

Alterations in Heart Rate Variability and Electroencephalogram during20‐MinuteExtremely Low Frequency Electric Field Treatment in Healthy Men during theEyes‐OpenCondition

AbstractOur previous study examined the neural effects of extremely low frequency electric field (ELF‐EF) using electroencephalogram (EEG) and heart rate variability (HRV) measurement and revealed that the theta power of EEG increases during 1‐min EF treatment (30 kV and 50 Hz). In the present study, the effects of a longer treatment duration were assessed. EF was applied between two electrodes, one above the head and the other under the feet, for 20 min to 10 healthy men sitting on a chair. Occipital EEG and HRV were measured in the eyes‐open condition. Power spectrum analysis showed that during the EF treatment, the power of alpha and theta rhythms as well as the low frequency component of HRV increased, and the heart rate decreased. These effects did not persist after the end of EF treatment. It is suggested that ELF‐EF treatment alters not only the brain activity but also the autonomic activity reflected in HRV. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Closed-Loop Adaptive Neurostimulation Technologies in Cognitive Rehabilitation of High-Tech Specialists.

The study involved specialists who applied to the clinic with complaints of occupational pain syndromes and work stress. For the treatment of pain syndromes, analgesic electrical nerve stimulation was used with the parameters automatically modulated by feedback signals from the subject's breathing rhythm. To correct stress-induced states, musical stimulation was used, automatically modulated by feedback signals from the narrow-band rhythmic components of the electroencephalogram (EEG) of the subject - alpha EEG oscillators. Treatment procedures without feedback from rhythmic processes were used as а control. In the control sessions without the feedback from human rhythmic processes, no significant effects of stimulation were noted. With electrical stimulation controlled by the patient's breathing (experiment 1), the most significant changes were observed in subjective pain scores, which dropped by half. A significant increase was noted in the power of the EEG alpha rhythm, respiration amplitude, and subjective ratings of well-being and mood. With music stimulation automatically modulated by the rhythmic components of the patient's EEG (experiment 2), there was a significant increase in the power of the EEG alpha rhythm, as well as a decrease in the level of emotional disadaptation and stress. The data obtained clearly indicate that the developed and tested technologies of adaptive neurostimulation can be used for the timely correction of the functional state and cognitive rehabilitation of high-tech specialists by effectively eliminating the risks of their functional reliability caused by occupational pain and stress.

CHANGES IN PSYCHO-PHYSIOLOGICAL INDICATORS AFTER TRAINING WITH THE USE OF NEURO-BIOFEEDBACK IN PEOPLE WHO HAD COVID-19

COVID-19 is an acute respiratory infection caused by SARS-CoV-2 coronavirus. The most common complications of this disease are viral pneumonia, acute respiratory failure and thromboembolism, up to 20% of patients suffer from long–term symptoms. The purpose of this study was to study the possibility of using neuro-biofeedback method in neuro-correction of patients who had suffered from COVID-19 disease with emotional disorders. The study involved 40 people (27 women and 13 men) who had suffered from COVID-19, experiencing emotional disorders and in need of rehabilitation, of whom 24 individuals made up the main group and 16 individuals – the control group. The age of the participants ranged from 25 to 73 years, the mean age was 42.25±2.59 years. Prior to the beginning and at the end of the study, both groups underwent tests: the "Depression Questionnaire", the State-Trait Anxiety Inventory, determination by the PSM-25 stress scale. The equipment "Neuro V" (Zelenograd, Russia) was used for neuro-biofeedback training. The neuro-feedback technology "Neuro V" makes it possible to use electroencephalography parameters for self-regulation. Stimulation of the alpha rhythm in the frequency range 8-14 Hz helped to change the psychoemotional state of the subjects. The changes were confirmed by valid diagnostic tests "Spielberger–Khanin Anxiety Scale", "Depression Questionnaire", indicators on PSM-25 stress scale, as well as a "subjective" decrease in the severity of the asthenic syndrome. The technique that we propose gave the opportunity to increase not only the indices of alpha rhythm power in the electroencephalography, but the subjective assessment of health as well.

Quantitative Evaluation of EEG-Biomarkers for Prediction of Sleep Stages.

Electroencephalography (EEG) is immediate and sensitive to neurological changes resulting from sleep stages and is considered a computing tool for understanding the association between neurological outcomes and sleep stages. EEG is expected to be an efficient approach for sleep stage prediction outside a highly equipped clinical setting compared with multimodal physiological signal-based polysomnography. This study aims to quantify the neurological EEG-biomarkers and predict five-class sleep stages using sleep EEG data. We investigated the three-channel EEG sleep recordings of 154 individuals (mean age of 53.8 ± 15.4 years) from the Haaglanden Medisch Centrum (HMC, The Hague, The Netherlands) open-access public dataset of PhysioNet. The power of fast-wave alpha, beta, and gamma rhythms decreases; and the power of slow-wave delta and theta oscillations gradually increases as sleep becomes deeper. Delta wave power ratios (DAR, DTR, and DTABR) may be considered biomarkers for their characteristics of attenuation in NREM sleep and subsequent increase in REM sleep. The overall accuracy of the C5.0, Neural Network, and CHAID machine-learning models are 91%, 89%, and 84%, respectively, for multi-class classification of the sleep stages. The EEG-based sleep stage prediction approach is expected to be utilized in a wearable sleep monitoring system.

Neurofeedback Training of Alpha Relative Power Improves the Performance of Motor Imagery Brain-Computer Interface.

Significant variation in performance in motor imagery (MI) tasks impedes their wide adoption for brain-computer interface (BCI) applications. Previous researchers have found that resting-state alpha-band power is positively correlated with MI-BCI performance. In this study, we designed a neurofeedback training (NFT) protocol based on the up-regulation of the alpha band relative power (RP) to investigate its effect on MI-BCI performance. The principal finding of this study is that alpha NFT could successfully help subjects increase alpha-rhythm power and improve their MI-BCI performance. An individual difference was also found in this study in that subjects who increased alpha power more had a better performance improvement. Additionally, the functional connectivity (FC) of the frontal-parietal (FP) network was found to be enhanced after alpha NFT. However, the enhancement failed to reach a significant level after multiple comparisons correction. These findings contribute to a better understanding of the neurophysiological mechanism of cognitive control through alpha regulation.

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).

Brain fragility among middle-aged and elderly patients from electroencephalogram during induction of anaesthesia.

Brain fragility among middle-aged and elderly patients from electroencephalogram during induction of anaesthesia.

Altered Emotional Phenotypes in Chronic Kidney Disease Following 5/6 Nephrectomy.

Increased prevalence of chronic kidney disease (CKD) and neurological disorders including cerebrovascular disease, cognitive impairment, peripheral neuropathy, and dysfunction of central nervous system have been reported during the natural history of CKD. Psychological distress and depression are serious concerns in patients with CKD. However, the relevance of CKD due to decline in renal function and the pathophysiology of emotional deterioration is not clear. Male Sprague Dawley rats were divided into three groups: sham control, 5/6 nephrectomy at 4 weeks, and 5/6 nephrectomy at 10 weeks. Behavior tests, local field potentials, and histology and laboratory tests were conducted and investigated. We provided direct evidence showing that CKD rat models exhibited anxiogenic behaviors and depression-like phenotypes, along with altered hippocampal neural oscillations at 1–12 Hz. We generated CKD rat models by performing 5/6 nephrectomy, and identified higher level of serum creatinine and blood urea nitrogen (BUN) in CKD rats than in wild-type, depending on time. In addition, the level of α-smooth muscle actin (α-SMA) and collagen I for renal tissue was markedly elevated, with worsening fibrosis due to renal failures. The level of anxiety and depression-like behaviors increased in the 10-week CKD rat models compared with the 4-week rat models. In the recording of local field potentials, the power of delta (1–4 Hz), theta (4–7 Hz), and alpha rhythm (7–12 Hz) was significantly increased in the hippocampus of CKD rats compared with wild-type rats. Together, our findings indicated that anxiogenic behaviors and depression can be induced by CKD, and these abnormal symptoms can be worsened as the onset of CKD was prolonged. In conclusion, our results show that the hippocampus is vulnerable to uremia.