Neural oscillatory changes play a critical role in pain and analgesia research. Previous studies on pain-related neural oscillations have primarily utilized electroencephalogram (EEG) power spectral analysis, revealing a strong correlation between alpha ( α) power and subjective pain perception. However, alpha power may be influenced by the baseline of the power spectrum, making it difficult to accurately capture the true changes in alpha oscillations. This study employed power spectral analysis and further applied a power spectral parameterization method, which decomposed the power spectrum into periodic and aperiodic components, to compare EEG α power in 50 primiparous women who underwent severe pain during the first stage of labor before and after epidural analgesia. The results indicated no significant differences in α power between pre- and post-analgesia conditions. However, following power spectral parameterization, the aperiodic component of the EEG significantly decreased after analgesia, whereas the periodic component of α power showed a significant increase. This study not only validates the effectiveness and validity of the power spectral parameterization method in analgesia research but also uncovers the differential regulatory mechanism by which analgesia modulates the periodic and aperiodic components of α oscillations.
Humans ; Electroencephalography/methods* ; Female ; Adult ; Alpha Rhythm ; Pregnancy ; Young Adult ; Analgesia, Epidural

Previous studies have proposed two cognitive mechanisms responsible for the Ebbinghaus illusion effect, i.e., contour interaction and size contrast. However, the neural underpinnings of these two mechanisms are largely unexplored. The present study introduced binocular depth to the Ebbinghaus illusion configuration and made the central target appear either in front of or behind the surrounding inducers in order to disturb size contrast instead of contour interaction. The results showed that the illusion effect, though persisted, was significantly reduced under the binocular depth conditions. Notably, the target with a larger perceived size reduced early alpha-band power (8-13 Hz, 0-100 ms after stimulus onset) at centroparietal sites irrespective of the relative depth of the target and the inducers, with the parietal alpha power negatively correlated with the illusion effect. Moreover, the target with a larger perceived size increased the occipito-parietal beta-band power (14-25 Hz, 200-300 ms after stimulus onset) under the no-depth condition, and the beta power was positively correlated with the illusion effect when the depth conditions were subtracted from the no-depth condition. The findings provided neurophysiological evidence in favor of the two cognitive mechanisms of the Ebbinghaus illusion by revealing that early alpha power is associated with low-level contour interaction and late beta power is linked to high-level size contrast, supporting the claim that neural oscillations at distinct frequency bands dynamically support different aspects of visual processing.
Humans ; Alpha Rhythm/physiology* ; Female ; Male ; Size Perception/physiology* ; Young Adult ; Adult ; Beta Rhythm/physiology* ; Photic Stimulation/methods* ; Illusions/physiology* ; Optical Illusions/physiology* ; Depth Perception/physiology*

BACKGROUND: One of the key issues in electroencephalogram (EEG) monitoring is accurate signal acquisition with less cumbersome electrodes. In this study, the L2 phase electro-deposited nanoporous platinum (L2-ePt) electrode is introduced, which is a new type of electrode that utilizes a stable nanoporous platinum surface to reduce the skin-electrode impedance. METHODS: L2-ePt electrodes were fabricated using electro-deposition technique. Then, the effect of the nanoporous surface on the surface roughness and the electrode impedance were observed from the L2-ePt electrodes and the flat platinum (FlatPt) electrode. The skin-electrode impedances of the L2-ePt electrodes, a gold cup electrode, and the FlatPt electrode were evaluated when placed on the hairy occipital area of the head in ten subjects. For the validation of using the L2-ePt electrode, a correlational analysis of the alpha rhythms was performed in the same subjects for simultaneous EEG recordings using the L2-ePt and clinically-used EEG electrodes. RESULTS: The results indicated that the L2-ePt electrode with a roughness factor of 200 had the lowest mean impedance performance. Moreover, the proposed L2-ePt electrode showed a significantly lower mean skin-electrode impedance than the FlatPt electrode. Finally, the EEG signal quality recorded by the L2-ePt electrode (r = 0.94) was comparable to that of the clinically-used gold cup electrode. CONCLUSION: Based on these results, the proposed L2-ePt electrode is suitable for use in various high-quality EEG applications.
Alpha Rhythm ; Electric Impedance ; Electrodes* ; Electroencephalography* ; Head ; Platinum*

OBJECTIVE: To study the effects of moxibustion at different time points on serum level of tumor necrosis factor-α (TNF-α) in rats with rheumatoid arthritis (RA), and to explore its regulation mechanism on circadian rhythm. METHODS: A total of 96 Sprague-Dawley (SD) adult rats were randomly assigned into a blank group, a model group, a moxibustion at 5-7 AM group and a moxibustion at 5-7 PM group, 24 rats in each group, half male and half female. Each group was further divided into a 0 AM group, a 6 AM group, a 12 N group and a 6 PM group, 6 rats in each group. All rats were treated with the 12 h/12 h light-dark cycle in the whole process of experiment. Except for the blank group, all rats were treated with intracutaneous injection of freund's complete adjuvant (FCA) at right foot pad to establish the RA model. The rats at the two moxibustion groups were treated with grain-sized moxibustion at "Shenshu" (BL 23) and "Zusanli" (ST 36) at 5-7 AM and 5-7 PM, respectively, one side per treatment, once a day; six treatments were taken as one course and 3 courses were given with an interval of one day between courses. The rats in the remaining groups were treated with identical fixation but without moxibustion intervention. The right foot volume was measured before model establishment, after model establishment and after treatment. The blood samples were collected after treatment and the serum level of TNF-α was measured by ELISA. The SPSS 21.0 software and Halberg Cosinor were adopted to analyze the experiment data. RESULTS: After treatment, compared with the blank group, the foot swelling severity was significantly increased in the model group, moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (all <0.01); compared with the model group, the foot swelling severity was significantly reduced in the moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (both <0.01). Compared with the blank group, the serum level of TNF-α was increased significantly in the model group and moxibustion at 5-7 AM group (both <0.05); compared with the model group, the serum level of TNF-α was reduced significantly in the moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (both <0.05). The serum level of TNF-α showed circadian rhythm in all the groups (all <0.05), and the peak appeared at night phase; compared with the blank group, the median value of TNF-α was increased significantly in the model group (<0.05), the peak phase was delayed and the amplitude was increased (<0.05); compared with the model group, the median value of TNF-α was significantly reduced in the moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (<0.01), the peak phase was advanced and the amplitude was reduced (<0.05). CONCLUSION Moxibustion could effectively reduce the serum level of TNF-α to relieve the foot swelling severity in RA rats. Moxibustion could regulate the circadian rhythm of TNF-α to play its effects on the inhibition of the synthesis of TNF-α. No efficacy is observed between the treatment at 5-7 AM and 5-7 PM.
Acupuncture Points ; Animals ; Arthritis, Rheumatoid ; Circadian Rhythm ; Female ; Male ; Moxibustion ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha

OBJECTIVES: Obsessive-compulsive disorder (OCD) and schizophrenia have many common clinical and neurocognitive features. However, not all of them share the same underlying mechanism. The aim of this study was to discover evidences that indicate a pathophysiological mechanism specific to OCD by comparing correlations of quantitative electroencephalography (QEEG) patterns and neurocognitive function in patients with OCD and schizophrenia. METHODS: Resting-state QEEG data of total 265 patients were acquired retrospectively and parameters such as absolute power, relative power and peak frequency were analyzed from the data. Stroop test and Trail Making Test results as well as demographic features were reviewed for this study. The correlation of neurocognitive functions and brain electrical activities in each group were assessed and compared by correlation analysis. RESULTS: Compared with the OCD group, the schizophrenia group performed poorly in neurocognitive tests. Mean values of QEEG parameters in patients with OCD and schizophrenia did not show significant differences. Both absolute and relative power of alpha rhythm in central and frontal regions showed significant positive correlation with Stroop test results in OCD patients. CONCLUSIONS: Findings in this study shows distinctive correlations between frontal executive dysfunction and frontal alpha rhythm in the OCD patients, both of which might be a candidate for endophenotype underlying obsessive rumination.
Alpha Rhythm ; Brain ; Electroencephalography* ; Endophenotypes ; Humans ; Obsessive-Compulsive Disorder* ; Retrospective Studies ; Schizophrenia* ; Stroop Test ; Trail Making Test

Studying the functional network during the interaction between emotion and cognition is an important way to reveal the underlying neural connections in the brain and nowadays, it has become a hot topic in cognitive neuroscience. Granger causality (GC), based on multivariate autoregressive (MVAR) model, and being able to be used to analyse causal characteristic of brain regions has been widely used in electroencephalography (EEG) in event-related paradigms research. In this study, we recorded the EEGs from 13 normal subjects (6 males and 7 females) during emotional face search task. We utilized Granger causality to establish a causal model of different brain areas under different rhythms at specific stages of cognition, and then convinced the brain dynamic network topological properties in the process of emotion and cognition. Therefore, we concluded that in the alpha band, (1) negative emotion face induced larger causal effects than positive ones; (2) 100-200ms emotional signal was the most prominent ones while 300-400ms and 700-800ms would take the second place; (3) The rear brain region modulated the front in the process of causal modulation; (4) The frontal and pillow area involved in the brain causal modulation as a key brain area; and (5) Negative partiality existed in the information processing, especially during 0-100ms after the negative expression stimulation.
Alpha Rhythm ; physiology ; Brain ; physiology ; Cell Communication ; physiology ; Cognition ; physiology ; Electroencephalography ; Emotions ; physiology ; Evoked Potentials ; physiology ; Female ; Humans ; Male ; Models, Neurological ; Multivariate Analysis ; Nerve Net ; physiology ; Neurons ; physiology

A single measurement of serum 17alpha-hydroxyprogesterone (17OHP) level can be unreliable because of its marked diurnal variation. We investigated the relationship of serum level of 17OHP with that of androstenedione (AD), which shows a smaller diurnal variation. And we tested whether the responses of these two hormones to low-dose ACTH stimulation are correlated in patients with 21-hydroxylase deficiency. Baseline serum 17OHP and AD levels were measured in 87 patients and a low-dose ACTH stimulation test was performed in 41 patients. The basal 17OHP level correlated positively with the basal AD level independently of sex, type of 21-hydroxylase deficiency, and the time of day of blood sampling (n = 87, R2 = 0.75, P < 0.001). The area under the curve of 17OHP and AD correlated positively with their respective basal levels. The fold-change increase in 17OHP after ACTH injection correlated negatively with the basal 17OHP level, but that of AD did not correlate with the basal AD level. The random serum 17OHP level, used in the clinic, is a reliable guide and a low-dose ACTH stimulation test provides no extra benefit for assessing the treatment adequacy in patients with 21-hydroxylase deficiency.
17-alpha-Hydroxyprogesterone/*blood ; Adolescent ; Adrenal Hyperplasia, Congenital/*diagnosis/drug therapy ; Adrenocorticotropic Hormone/*diagnostic use ; Androstenedione/*blood ; Circadian Rhythm ; Female ; Humans ; Male ; Steroid 21-Hydroxylase/metabolism ; Young Adult

Complex Morlet wavelets, as a wavelet function, is most commonly used in the time-frequency analysis of EEG signal and in the extraction of the instantaneous power and phase. This article explains how to use the Morlet wavelet transform for obtaining EEG's alpha wave energy distribution over time, and how to use the EEG data of mental arithmetic experiment for obtaining the changes of the alpha wave duration.
Algorithms ; Alpha Rhythm ; Electroencephalography ; methods ; Humans ; Signal Processing, Computer-Assisted ; Wavelet Analysis

The alpha rhythm in electroencephalograph has been associated with the mental state of the brain. The aim of the present study was to analyze the complexity of the alpha activity in depression patients by Renyi entropy (RE) under two conditions, i.e., resting with eyes closed followed by a simple mental arithmetic. The EEGs were recorded in 20 depression patients and 20 age-matched control subjects. Results showed that the alpha activity of depression patients is more complex during resting and is more regular during the mental arithmetic than that of the controls. RE analysis can well characterize the alpha activity in depression patients and could be a valuable tool to study cognitive process and also a potential effective approach for the diagnosis of depression.
Adult ; Alpha Rhythm ; Depression ; physiopathology ; Electroencephalography ; Entropy ; Female ; Humans ; Male ; Signal Processing, Computer-Assisted

In regard to the controls and schizophrenia EEGs, we have got alpha rhythm from three points of view and verified the nonlinearity of the three kinds of rhythms. The results show that neither normal EEG alpha nor patients EEG alpha have the typical nonlinear characteristics. Therefore, we could not blindly use the theories of nonlinear dynamics to analyze the rhythm of brain wave.
Alpha Rhythm ; statistics & numerical data ; Brain ; physiology ; physiopathology ; Electroencephalography ; statistics & numerical data ; Humans ; Nonlinear Dynamics ; Schizophrenia ; physiopathology