Absolute Theta Power Research Articles

Exploring trait differences in neurofeedback learners: a single-session sham-controlled pilot study

Neurofeedback (NF) is a form of biofeedback that involves individuals monitoring and shifting brain activity towards a desired direction. The objective of this study was to investigate whether there are differences between NF learners and non-learners on psychometric traits such as the NEO PI-R personality factors, self-regulation questionnaire (SRQ) and the need for cognition scale (NFC). A total of 34 participants were randomly allocated to a single-blind randomised sham-controlled protocol 3-arm study of single-session theta NF. Twelve participants were administered a spatially defined frontal-midline theta (FM-theta) group, 11 to a functionally defined medial temporal/parietal lobe (MTL-theta) group and 11 allocated to a yoked sham NF group. The baseline session included screening of participants, trait-based behavioural measures (SRQ, NFC and NEO PI-R) and the completion of cognitive tasks with electroencephalography (EEG) recording to determine individualised peak theta activity for NF training. NF learners and non-learners were evaluated using changes in absolute theta power and the percentage of time spent above threshold using Spearman’s correlation coefficient from a total of 30-minutes of NF exposure. Significant differences in psychometric traits between NF learners and non-learners differed depending on learning metrics. Results indicated that NF learners reported higher SRQ total scores, SRQ decision making, SRQ goal setting subfactors and NEO PI-R conscientiousness, but were significantly lower in NEO PI-R extraversion compared to non-learners. This study demonstrates that learning outcomes vary based on the metrics used and emphasises the importance of selecting appropriate learning metrics and further examination of learning within sham NF training.

EFFECTS OF INAUDIBLE THETA BINAURAL BEAT ON BRAIN WAVES

Auditory binaural beats (BBs) stimulation is a method used to support the assumption that artificial external stimuli can generate specific brain waves. This study aimed to examine the effects of BBs that induce brain waves only based on a different frequency using an inaudible baseline frequency. The experiment was conducted among 18 adults in their 20s (11 male and 7 female). A baseline frequency of 18,000[Formula: see text]Hz and BBs with a difference frequency of 5[Formula: see text]Hz was presented, and the changes in electroencephalogram were observed. Power spectrum analysis was performed, and the absolute power of the theta-band frequency range (4–7[Formula: see text]Hz) was averaged. Absolute theta power was compared between phases without binaural beats (non-BBs) and with binaural beats ([Formula: see text]-BBs) using the Wilcoxon signed-rank test. Theta waves in [Formula: see text]-BBs significantly increased in most brain regions (central, parietal, temporal, and occipital) compared to those in non-BBs. This study is significant because it focused solely on the effects of the BBs-inducing theta waves using a frequency difference, excluding the effect of sound perception.

Unveiling the Scented Symphony: Exploring Lemongrass (Cymbopogon Citratus) Essential Oil's Influence on Brain Waves Through Quantitative Electroencephalogram

Background: This study explores the captivating query about how olfactory stimulation affects neural activity, particularly examining changes in the absolute and relative power of lower frequency waves (delta and theta across various brain regions). This investigation employs Quantitative Electroencephalogram (QEEG) to analyze the effects of exposure to the aroma of lemongrass (Cymbopogon Citratus) essential oil. Aim: To evaluate the impact of inhaling lemongrass (Cymbopogon Citratus) essential oil aroma on EEG patterns in awake healthy female adults, employing power spectral analysis. Materials and Method: In this self-controlled experiment, 30 healthy adult female participants were exposed to the water mist as control and after taking baseline recording, they inhaled aromatic mist from room air, and again brain activities were recorded using QEEG. Data was collected from scalp electrodes readings and outcomes from before and after exposure to the aroma were compared. This analysis was strengthened by comparing the results between exposure to water mist and oil mist employing the Wilcoxon Matched-Pairs Signed Rank Test. Results: Significant elevation of absolute and relative power of theta in prefrontal region (p=0.002; p=0.000) along with rise of delta and theta absolute power in frontal area (p=0.000; p=0.000) was observed. Conclusion: This study sheds light onto the background oscillatory fluctuations in lower frequency bands that may indicate more relaxed state of brain activity due to inhalation of lemongrass essential oil. J Med Coll Women Hosp.2024; 20 (1):16-22

Depression Identification Using Asymmetry Matrix and Machine Learning Algorithms

Purpose: Developing an efficient and reliable method for the identification of depression is highly important. This paper aims to propose an approach for depression diagnosis using an interhemispheric asymmetry matrix and machine learning algorithms.
 Materials and Methods: First, an EEG signal was acquired from 24 depressed patients and 24 healthy subjects. The EEG signal was acquired from participants for 5 minutes in Eyes-Closed (EC) and 5 minutes in Eyes-Open (EO) condition. After preprocessing data, interhemispheric asymmetry for absolute and relative powers of theta and beta frequency bands, theta-to-alpha power ratio, and Individual Alpha Frequency (IAF) features were computed. Then, the proposed asymmetry matrix is used as a feature for statistical and classification analysis. In this paper, the classification was performed using a Support Vector Machine (SVM), logistic regression, and Multi-Layer Perceptron (MLP).
 Results: The results demonstrated that central and temporal theta absolute power, central and temporal IAF asymmetries in the EC condition and occipital beta absolute power, temporal theta relative power, temporal theta-to-alpha power ratio, and temporal IAF asymmetries in the EO condition have significant differences between depressed and healthy groups. Findings show that beta absolute power asymmetry in the occipital region and EO condition is a good biomarker for depression identification with 77.1% accuracy using the Gaussian SVM classifier.
 Conclusion: The results of this study show performance of proposed asymmetry matrix features in depression detection. Findings show that beta absolute power asymmetry in the occipital region and EO condition is a good biomarker for depression identification.

EEG‐based neural biomarker for diagnosis and assessment of mild cognitive impairment and Alzheimer’s disease

AbstractBackgroundElectroencephalogram (EEG) has emerged as a non‐invasive tool to detect the aberrant neuronal activity related to different stages of Alzheimer’s disease (AD). However, the effectiveness of EEG in the precise diagnosis and prediction of AD and its preclinical stage, mild cognitive impairment (MCI), has yet to be fully elucidated. In this study, we aimed to identify key EEG biomarkers that are effective in distinguishing patients at the early stage of AD and monitoring the progression of AD.MethodA total of 890 participants, including 189 patients with MCI, 330 patients with AD, 125 patients with other dementias (frontotemporal dementia, dementia with Lewy bodies, and vascular cognitive impairment), and 246 healthy controls (HC) were enrolled. Biomarkers were extracted from resting‐state EEG recordings for a three‐level classification of HC, MCI, and AD. The optimal EEG biomarkers were then identified based on the classification performance. Random forest regression was used to train a series of predictive models by combining participants’ EEG biomarkers, demographic information (i.e., sex, age), CSF biomarkers, and APOE phenotype for predicting the disease progression and individual’s cognitive function.ResultThe identified EEG biomarkers achieved over 70% accuracy in the three‐level classification of HC, MCI, and AD. Among all six groups, the most prominent effects of AD‐linked neurodegeneration on EEG metrics were localized at parieto‐occipital regions. Noteworthy, the absolute theta power of channel O2 was negatively correlated with Aβ42 (r = ‐0.358, p < 0.001) and positively correlated with p‐tau (r = 0.442, p < 0.001). In terms of cognitive assessment, the Hjorth mobility of channel O1, O2 and P4 were found to be positively associated with MMSE and MoCA scores (r = 0.416‐0.464, all p < 0.001). In the predictive analyses, the optimal EEG features were more effective than the CSF + APOE biomarkers in predicting the age of onset and disease course, whereas the combination of EEG + CSF + APOE measures achieved the best performance for all targets of prediction.ConclusionOur study indicates that EEG can be used as a useful screening tool for the diagnosis and disease progression evaluation of MCI and AD.

Differences between hemispheres and in saccade latency regarding volleyball athletes and non-athletes during saccadic eye movements: an analysis using EEG.

The saccadic eye movement is responsible for providing focus to a visual object of interest to the retina. In sports like volleyball, identifying relevant targets quickly is essential to a masterful performance. The training improves cortical regions underlying saccadic action, enabling more automated processing in athletes. We investigated changes in the latency during the saccadic eye movement and the absolute theta power on the frontal and prefrontal cortices during the execution of the saccadic eye movement task in volleyball athletes and non-athletes. We hypothesized that the saccade latency and theta power would be lower due to training and perceptual-cognitive enhancement in volleyball players. We recruited 30 healthy volunteers: 15 volleyball athletes (11 men and 4 women; mean age: 15.08 ± 1.06 years) and 15 non-athletes (5 men and 10 women; mean age: 18.00 ± 1.46 years). All tasks were performed simultaneously with electroencephalography signal recording. The latency of the saccadic eye movement presented a significant difference between the groups; a shorter time was observed among the athletes, associated with the players' superiority in terms of attention level. During the experiment, the athletes observed a decrease in absolute theta power compared to non-athletes on the electrodes of each frontal and prefrontal area. In the present study, we observed the behavior of reaction time and absolute theta power in athletes and non-athletes during a saccadic movement task. Our findings corroborate the premise of cognitive improvement, mainly due to the reduction of saccadic latency and lower beta power, validating the neural efficiency hypothesis.

The Increase of Theta Power and Decrease of Alpha/Theta Ratio as a Manifestation of Cognitive Impairment in Parkinson's Disease.

In this study, we aim to assess and examine cognitive functions in Parkinson's Disease patients using EEG recordings, with a central focus on characteristics associated with a cognitive decline. Based on neuropsychological evaluation using Mini-Mental State Examination, Montreal Cognitive Assessment, and Addenbrooke's Cognitive Examination-III, 98 participants were divided into three cognitive groups. All the particpants of the study underwent EEG recordings with spectral analysis. The results revealed an increase in the absolute theta power in patients with Parkinson's disease dementia (PD-D) compared to cognitively normal status (PD-CogN, p=0.00997) and a decrease in global relative beta power in PD-D compared to PD-CogN (p=0.0413). An increase in theta relative power in the left temporal region (p=0.0262), left occipital region (p=0.0109), and right occipital region (p=0.0221) were observed in PD-D compared to PD-N. The global alpha/theta ratio and global power spectral ratio significantly decreased in PD-D compared to PD-N (p = 0.001). In conclusion, the increase in relative theta power and the decrease in relative beta power are characteristic changes in EEG recordings in PD patients with cognitive impairment. Identifying these changes can be a useful biomarker and a complementary tool in the neuropsychological diagnosis of cognitive impairment in Parkinson's Disease.

Quantitative Electroencephalography and Balance Test Correlations in Patients with Chronic Patellofemoral Pain.

Quantitative Electroencephalography (QEEG) is a tool helping better understand the electrical activity of the brain and a non-invasive method to assess cortical activity. To date, the brain activity of patients with chronic patellofemoral pain (PFP) has not been investigated. The current study aimed to investigate the effect of PFP on higher levels of the central nervous system by assessing the correlation between QEEG and modified excursion balance test (mSEBT) in patients with PFP. Twenty-two patients with chronic PFP participated in this observational study. Their cortical electrical activity was recorded in a resting state with their eyes open, via a 32-channel QEEG. C3, C4, and Cz were considered as regions of interest. In addition to QEEG, the balance performance of the participants was evaluated via mSEBT. The obtained findings revealed a negative and moderate to high correlation between theta absolute power and posteromedial direction of mSEBT in C4 (P 0.000, r -0.68), Cz (P 0.001, r -0.66), and C3 (P 0.000, r -0.70). Additionally, a significantly close correlation is between alpha absolute power in C3 (P 0.001, r -0.70), C4 (P 0.000, r -0.71), and Cz (P 0.000, r -0.74) and the posteromedial direction of mSEBT. No significant correlations were between the other two directions of mSEBT, alpha, and theta. According to our results, balance impairment in patients with chronic PFP correlated with their QEEG neurodynamics. Moreover, our findings demonstrated the efficiency of QEEG as a neuromodulation method for patients with PFP.

Changes in Human Electroencephalographic Activity in Response to Agastache rugosa Essential Oil Exposure.

Agastache rugosa (Korean mint) is an important medicinal and aromatic plant and its aerial parts have a pleasant fragrance. A. rugosa leaves are used as an ingredient in salads and soups for enhancing the aroma and taste of foods in Korea. However, there is no report on the influence of the aroma of A. rugosa on human psychophysiological activity. Therefore, the present study aimed to investigate the effect of exposure to the essential oil of Korean A. rugosa on human electroencephalographic (EEG) activity. The essential oil of A. rugosa was isolated using steam distillation extraction and its composition was determined by gas chromatography and mass spectrometry (GC–MS) analysis. In the EEG study, 38 healthy volunteers (19 men and 19 women) participated. The EEG readings were analyzed for 25 EEG indices from 29 electrodes placed on the scalp according to the international 10–20 system. The major component in the essential oil of A. rugosa was estragole (89.49%) followed by D-limonene (3.40%), menthone (1.80%), and pulegone (1.86%). In the EEG study, significant decreases in absolute theta (AT) and relative theta (RT) power spectra were observed during the exposure to A. rugosa essential oil when compared to that of no odor exposure. Whereas relative alpha (RA), relative slow alpha (RSA), spectral edge frequency 50% (SEF50), and spectral edge frequency 50% of alpha (ASEF) power spectra values significantly increased. These results reveal that the EEG power spectra changes incurred during the exposure to the essential oil of A. rugosa may be associated with the enhancement of freshness and concentration states of the human brain.

One-Year Follow-Up of Healthy Older Adults with Electroencephalographic Risk for Neurocognitive Disorder After Neurofeedback Training.

Background:In healthy older adults, excess theta activity is an electroencephalographic (EEG) predictor of cognitive impairment. In a previous study, neurofeedback (NFB) treatment reinforcing reductions theta activity resulted in EEG reorganization and cognitive improvement.Objective:To explore the clinical applicability of this NFB treatment, the present study performed a 1-year follow-up to determine its lasting effects.Methods:Twenty seniors with excessive theta activity in their EEG were randomly assigned to the experimental or control group. The experimental group received an auditory reward when the theta absolute power (AP) was reduced. The control group received the reward randomly.Results:Both groups showed a significant decrease in theta activity at the training electrode. However, the EEG results showed that only the experimental group underwent global changes after treatment. These changes consisted of delta and theta decreases and beta increases. Although no changes were found in any group during the period between the posttreatment evaluation and follow-up, more pronounced theta decreases and beta increases were observed in the experimental group when the follow-up and pretreatment measures were compared. Executive functions showed a tendency to improve two months after treatment which became significant one year later.Conclusion:These results suggest that the EEG and behavioral benefits of this NFB treatment persist for at least one year, which adds up to the available evidence contributing to identifying factors that increase its efficacy level. The relevance of this study lies in its prophylactic features of addressing a clinically healthy population with EEG risk of cognitive decline.

The increase in absolute theta power and the inhibition of light stimulus in cybersickness

Cybersickness results from the visual vestibule conflict, that is, the incoherence between the sensations related to real movement, in the virtual environment, and the visual stimuli. In response to the virtual environment, one can observe discomforts such as nausea, difficulty in concentrating, and headaches, among others. There are no studies in the literature that analyze the inhibition control of light stimuli in individuals sensitive to Cybersickness. Therefore, this study looked at the control of light stimulus inhibition in Cybersickness. The Sickness Susceptibility Questionnaire was used to divide the subjects into experimental and control groups, and quantify the signs and symptoms, comparing them before and after 3D virtual immersion and. Participants in both groups were examined with EEGq for absolute theta band power in the dorsolateral prefrontal cortex and ventrolateral prefrontal cortex during the light stimulus inhibition task before and after participants watched the 3D video. The partial results showed that there was an increase in the absolute theta band power in both groups comparing the moments before and after, as well as a significant difference in the experimental group compared to the control, for the same moment. Thus, it was observed that individuals who were exposed to 3D virtual reality and developed Cybersikness, showed greater absolute theta band power in the areas studied.

COVID-19: Effects on Brain and qEEG Correlates-A Window Into the Future

While the world is aware of Covid’s devastating effect on the world’s health and economy worldwide, this event has highlighted the need to understand how viruses and other micro infectious events enter and effect the brain contributing to changes in function and behavior. Given that this and other viruses do indeed enter the brain, studies are now being turned to understand possible residual effects on behavior and brain function. More than ever, the need to understand how such infiltration leads to demyelinating and general neuroinflammatory processes and this has been noted effecting frontal lobes and brainstem structures. Initial structural neuroimaging studies have evidenced generalized encephalopathies and damage particularly to medial temporal regions. Studies showing that as much as six months following discharge from hospitalization, there are reports that over 30% of patients are experiencing decline in cognitive functioning and over 20% of patients experience significant mood regulation problems. Functional neuroimaging studies have corroborated structural findings in noting dysfunction as expected changes in the frontal regions. EEG studies have also noted frontal regions with increased delta corresponding to these findings. COVID-19 patients with resultant seizures, focal areas have been identified in the temporal, frontotemporal, and central-parietal regions. This presentation will summarize initial efforts to review a clinical sample of qEEG correlates resulting from COVID infection including sLORETA analyses that can help to understand the scaled vulnerability for certain areas of the brain for such infections and shed more light on why certain qEEG features are likely to be expected in the presence of underlying neuroinflammatory mechanisms. Preliminary cases studies with patients post COVID-19 exposure as well as non-exposed neurotypical cases experiencing the neuroinflammatory effects of the COVID vaccination will be presented and reviewed. These cases will illustrate the emerging findings that evidence increased delta and theta absolute power in bilateral frontal poles, fronto-temporal regions and central-parietal regions and increased volumetric deviations in the frontal and temporal regions by sLORETA analyses with concomitant changes in aspects of cognition and mood regulation. Current vaccines being used to prevent more serious effects of the COVID-19 and potential variants can stimulant the immune system to trigger similar cytokine storms in some individuals and can trigger neuroinflammatory effects on the brain. qEEG may have the ability to provide biomarkers for individuals who may have cytokine storms by any of number of challenges to the immune system.

Associations of socioeconomic and other environmental factors with early brain development in Bangladeshi infants and children

Studies of infants growing up in high-income countries reveal developmental changes in electroencephalography (EEG) power whereby socioeconomic factors - specifically, low SES and low income - are associated with lower EEG power in infants aged newborn to nine months. In the current paper we explore relationships of spectral EEG power across three regions (frontal, central, and parietal) and four frequency bands (theta, alpha, beta, and gamma) with socioeconomic and psychosocial factors in a cohort of n = 160 6-month-old infants and n = 187 36-month-old children living in Dhaka, Bangladesh. Household wealth is assessed as a multi-dimensional composite score encompassing income, assets, and housing materials. Psychosocial factors include maternal perceived stress and family caregiving activities. Among the 6-month-old infants we do not observe any association of household wealth or psychosocial factors with EEG power. Among the 36-month-old children, we find that household wealth is negatively associated absolute power in the beta and gamma bands across frontal, central, and parietal electrodes. We also find that higher reports of maternal perceived stress are associated with more absolute theta power in frontal and central regions in the 36-month-old children. The finding of a negative relationship of household wealth with beta and gamma power in 36-month-old children differs from findings previously observed in infants in high-income countries. Overall, findings suggest that children’s environment continues to influence the development of EEG oscillations and provide support for the utility of EEG to quantify developmental effects of early life experiences on neural functional outcomes in low income countries.

Individual Alpha Peak Frequency, an Important Biomarker for Live Z-Score Training Neurofeedback in Adolescents with Learning Disabilities.

Learning disabilities (LDs) have an estimated prevalence between 5% and 9% in the pediatric population and are associated with difficulties in reading, arithmetic, and writing. Previous electroencephalography (EEG) research has reported a lag in alpha-band development in specific LD phenotypes, which seems to offer a possible explanation for differences in EEG maturation. In this study, 40 adolescents aged 10–15 years with LDs underwent 10 sessions of Live Z-Score Training Neurofeedback (LZT-NF) Training to improve their cognition and behavior. Based on the individual alpha peak frequency (i-APF) values from the spectrogram, a group with normal i-APF (ni-APF) and a group with low i-APF (li-APF) were compared in a pre-and-post-LZT-NF intervention. There were no statistical differences in age, gender, or the distribution of LDs between the groups. The li-APF group showed a higher theta absolute power in P4 (p = 0.016) at baseline and higher Hi-Beta absolute power in F3 (p = 0.007) post-treatment compared with the ni-APF group. In both groups, extreme waves (absolute Z-score of ≥1.5) were more likely to move toward the normative values, with better results in the ni-APF group. Conversely, the waves within the normal range at baseline were more likely to move out of the range after treatment in the li-APF group. Our results provide evidence of a viable biomarker for identifying optimal responders for the LZT-NF technique based on the i-APF metric reflecting the patient’s neurophysiological individuality.

Coordination Cost and Super-Efficiency in Teamwork: The Role of Communication, Psychological States, Cardiovascular Responses, and Brain Rhythms

To advance knowledge on the psychophysiological markers of “coordination cost” in team settings, we explored differences in meta-communication patterns (i.e., silence, speaking, listening, and overlap), perceived psychological states (i.e., core affect, attention, efficacy beliefs), heart rate variability (i.e., RMSSD), and brain rhythms (i.e., alpha, beta and theta absolute power) across three studies involving 48 male dyads (Mage = 21.30; SD = 2.03). Skilled participants cooperatively played three consecutive FIFA-17 (Xbox) games in a dyad against the computer, or competed against the computer in a solo condition and a dyad condition. We observed that playing in a team, in contrast to playing alone, was associated with higher alpha peak and global efficiency in the brain and, at the same time, led to an increase in focused attention as evidenced by participants’ higher theta activity in the frontal lobe. Moreover, we observed that overtime participants’ brain dynamics moved towards a state of “neural-efficiency”, characterized by increased theta and beta activity in the frontal lobe, and high alpha activity across the whole brain. Our findings advance the literature by demonstrating that (1) the notion of coordination cost can be captured at the neural level in the initial stages of team development; (2) by decreasing the costs of switching between tasks, teamwork increases both individuals’ attentional focus and global neural efficiency; and (3) communication dynamics become more proficient and individuals’ brain patterns change towards neural efficiency over time, likely due to team learning and decreases in intra-team conflict.

Poor working memory performance in healthy elderly adults with electroencephalographic risk of cognitive decline affects syntactic processing

ObjectiveTo examine the effects of working memory (WM) load and gender agreement on sentence processing as a function of the electroencephalographic risk (i.e., abnormally high values of theta absolute power) of cognitive decline in older adults. MethodsEvent-related potentials (ERPs) were collected from Spanish speakers (22 older adults belonged to the Risk group, mean age = 67.7 years; 22 older adults belonged to the Control group, mean age = 65.2 years) while reading sentences to detect grammatical errors. Sentences varied with regard to (1) the gender agreement of the noun and adjective, where gender of the adjective either agreed or disagreed with the noun, and (2) WM load (i.e., the number of words between the noun and adjective in the sentence). ResultsThe Risk group showed a lower percentage of correct answers and longer reaction times than the Control group. The Risk group also showed a different pattern of ERP components, which was characterized by smaller amplitude and longer latency of the P600a component under high WM load conditions. ConclusionThe findings suggest that the Risk group shows difficulties integrating information associated with the previous sentence context. SignificanceThe electroencephalographic risk factor of cognitive decline might be not only a predictor of but also an indicator of current decline.

Predicting the non-survival outcome of large hemispheric infarction patients via quantitative electroencephalography: Superiority to visual electroencephalography and the Glasgow Coma Scale

BackgroundQuantitative electroencephalography (QEEG) data are useful to predict outcomes of cerebral infarction patients. This study was performed to establish the value of QEEG in the prediction of outcomes in patients with large hemispheric infarction (LHI). MethodsA prognostic blinded cohort study was conducted on patients diagnosed with LHI in our neurocritical care unit. The electroencephalography (EEG) was recorded at the bedside within 3 days of LHI onset. Each EEG expert scored the raw EEG, and QEEG parameters including the absolute power, (delta + theta)/ (alpha + beta) ratio and brain symmetry index were obtained afterwards. Baseline data including Glasgow Coma Scale (GCS) was recorded at the meantime. Outcomes included survival or non-survival at the time of discharge and 6 months after the onset of LHI. ResultsA total of 50 patients entered into the final analysis. There were no differences in baseline data or visual EEG grades between survival and non-survival groups. QEEG analysis showed that the absolute theta power of all of the electrodes and the contralateral electrodes was significantly higher in the non-survival group than in the survival group at discharge. Multivariable logistic regression analysis demonstrated that theta power of the contralateral electrodes was an independent predictor of death at discharge and at 6 months. Compared to the GCS and EEG grading, the QEEG index exhibited higher accuracy in predicting non-survival outcomes. ConclusionsAmong QEEG indices, theta power is valuable in predicting non-survival outcome in participants and is superior to visual EEG and GCS.

Effect of Electroacupuncture Stimulation at Different Frequencies On Brain Waves

Frequency and intensity of stimulation are important parameters in electroacupuncture. This study investigated the effect of electro acupuncture at different frequencies and intensities via electroencephalography. Bilateral ST36 (zusanli) of 15 healthy participant volunteers were stimulated via two different modes of electroacupuncture: 2Hz (low frequency) with a highintensity mode (5-6mA), and 120Hz (high frequency) with a low-intensity (22.5mA) mode. Eight-channel EEG were recorded before and during the electro acupuncture stimulation. After eliminating artifacts from raw EEG data, power spectrum analysis was done according to frequency bands: theta (48Hz), alpha (8-13Hz), beta (13-30Hz), and gamma (30-50Hz) bands. With electroacupuncture stimulation, the absolute theta power was decreased compared with baseline in the overall region (P<0.05 in all channel with some minor exceptions). Moreover, high frequency electroacupuncture stimulation increased the absolute alpha power in the posterior region (P=0.047 in left; P=0.125 in right). Further, high frequency electroacupuncture stimulation decreased the absolute beta power in prefrontal region (P=0.006 in left; P=0.006 in right), and decreased the absolute gamma power in posterior region (P=0.035 in right). It is likely that electroacupuncture at ST36 affects brain waves differently depending on stimulation frequency.

Effects of Dark Chocolate Intake on Brain Electrical Oscillations in Healthy People.

Dark chocolate is rich in flavonoids that can have effects on body composition and cognitive performance. The aim of this study was to analyze the effects of acute and subchronic chocolate intake on electrical brain oscillations. A study with 20 healthy subjects (mean age of 24.15 years) and a control group with five subjects (mean age of 23.2 years) was carried out. In the acute effect study, the subjects’ intake was dark chocolate (103.72 mg/kg of body weight) rich in flavonoids and low in calories as in fasting. In the control group, the subjects intake was only low-calorie milk. For the subchronic effect, a daily dose of dark chocolate was given for eight days. The baseline electroencephalogram (EEG) was recorded before dark chocolate intake; at 30 min, the second EEG was carried out; on the eighth day, the third and fourth EEGs were performed before and after the last intake. In acute and subchronic intake, Delta Absolute Power (AP) decrease was observed in most brain regions (p < 0.05), except in the right fronto-centro-temporal regions. In the Theta band, there was a generalized decrease of the AP of predominance in the left fronto-centro-temporal regions. In contrast, an increase in AP was observed in the temporo-occipital regions in the Alpha band, and in the right temporal and parieto-occipital regions in the Beta band. The control group did not have significant changes in brain oscillations (p > 0.05). We concluded that acute and subchronic chocolate intake decreased the Delta and Theta AP and increased Alpha and Beta AP in most brain regions.

Repetitive Transcranial Magnetic Stimulation changes absolute theta power during cognitive/motor tasks

Repetitive Transcranial Magnetic Stimulation (rTMS) studies are used to test motor imagery hypothesis. Motor Imagery (MI) represents conscious access to contents of movement intention, generally executed unconsciously during motor preparation. The main objective of this study was to investigate electrophysiological changes, which occurred before and after low-frequency rTMS application when we compared three different tasks: execution, action observation and motor imagery of finger movement. We hypothesize that absolute theta power over frontal regions would change between sensorimotor integration tasks and after 1 Hz of rTMS application. Eleven healthy, right-handed volunteers of both sexes (5 males, 6 females; mean age 28 ± 5 years), with no history of psychiatric or neurological disorders, participated in the experiment. After performing the tasks randomly, subjects were submitted to 15 min of low-frequency rTMS applied on Superior Parietal Cortex (SPC) and performed the tasks again. All tasks were executed simultaneously with Eletroencephalography (EEG) signals recording. Our results clarified the specificity of each sub-region during MI activity. Frontopolar cortex presented involvement with motor process and showed main effect for task and moment. Inferior frontal gyrus presented involvement with long-term memory retrieval and showed interaction between task and moment in the left hemisphere while the right hemisphere showed a main effect for task and moment. The lack of the main effect for conditions on the anterior frontal cortex collaborates with the hypothesis that in this region an integrated circuit of performance monitoring exists.