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Sample records for eeg alpha phenotypes

  1. Magnetic Resonance Therapy Improves Clinical Phenotype and EEG Alpha Power in Posttraumatic Stress Disorder

    PubMed Central

    Taghva, Alexander; Silvetz, Robert; Ring, Alex; Kim, Keun-young A.; Murphy, Kevin T.; Liu, Charles Y.; Jin, Yi

    2015-01-01

    Background: Posttraumatic stress disorder (PTSD) is a disabling and prevalent psychiatric disorder with limited effective treatment options. In addition to the clinical features of the disease, pathologic changes in the electroencephalogram (EEG), including decreased alpha power, have been reported. Objectives: To determine if magnetic brain stimulation can induce normalization of EEG abnormalities and improve clinical symptoms in PTSD in a preliminary, open-label evaluation. Materials and Methods: We reviewed prospectively-collected data on 21 veterans that were consecutively-treated for PTSD. Magnetic resonance therapy (MRT) was administered for two weeks at treatment frequencies based on frequency-domain analysis of each patient’s dominant alpha-band EEG frequencies and resting heart rate. Patients were evaluated on the PTSD checklist (PCL-M) and pre- and post-treatment EEGs before and after MRT. Results: Of the 21 patients who initiated therapy, 16 completed treatment. Clinical improvements on the PCL-M were seen in these 16 patients, with an average pre-treatment score of 54.9 and post-treatment score of 31.8 (P < 0.001). In addition, relative global EEG alpha-band (8 - 13 Hz) power increased from 32.0 to 38.5 percent (P = 0.013), and EEG delta-band (1 - 4 Hz) power decreased from 32.3 percent to 26.8 percent (P = 0.028). Conclusions: These open-label data show trends toward normalization of EEG and concomitant clinical improvement using magnetic stimulation for PTSD. PMID:26839865

  2. Low voltage alpha EEG phenotype is associated with reduced amplitudes of alpha event-related oscillations, increased cortical phase synchrony, and a low level of response to alcohol.

    PubMed

    Ehlers, Cindy L; Wills, Derek N; Phillips, Evelyn; Havstad, James

    2015-10-01

    Low voltage EEG (LVEEG) is a heritable phenotype that differs depending on ancestral heritage, yet its impact on brain networks and cognition remain relatively unexplored. In this study we assessed energy and task related phase locking of event-related oscillation (EROs), behavioral responses, measures of IQ and personality, and expected responses to alcohol in a large sample of individuals with LVEEG compared to those with higher voltage variants. Participants (n=762) were recruited from a Native American community and completed a diagnostic interview, the Quick Test, the Subjective High Assessment Scale Expectation Version (SHAS-E) and the Maudsley Personality Inventory. Clinical and spectral analyzed EEGs were collected for determination of the presence of a LVEEG variant. EROs were generated using a facial expression recognition task. Participants with LVEEG (n=451) were significantly more likely to be older, married and have higher degrees of Native American heritage but did not differ in gender, income or education. Individuals with LVEEG were also found to have decreased energy in their alpha EROs, increased phase locking between stimulus trials, and increased phase-locking between cortical brain areas. No significant differences in the cognitive tests, personality variables or alcohol dependence or anxiety diagnoses were found, however, individuals with LVEEG did report a larger number of drinks ever consumed in a 24-h period and a less intense expected response to alcohol. These data suggest that alpha power in the resting EEG is highly associated with energy and cortical connectivity measures generated by event-related stimuli, as well as potentially increased risk for alcohol use. PMID:26151497

  3. EEG Alpha Power and Intelligence.

    ERIC Educational Resources Information Center

    Doppelmayr, M.; Klimesch, W.; Stadler, W.; Pollhuber, D.; Heine, C.

    2002-01-01

    Tested whether alpha power in different sub-bands is selectively related to intelligence. For 74 Austrian subjects, the EEG was recorded during a resting session and 2 different intelligence tests were performed. Findings show a strong positive correlation between intelligence and alpha power. (SLD)

  4. HTR3B is associated with alcoholism with antisocial behavior and alpha EEG power—an intermediate phenotype for alcoholism and co-morbid behaviors

    PubMed Central

    Ducci, Francesca; Enoch, Mary-Anne; Yuan, Qiaoping; Shen, Pei-Hong; White, Kenneth V.; Hodgkinson, Colin; Albaugh, Bernard; Virkkunen, Matti; Goldman, David

    2009-01-01

    Alcohol use disorders (AUD) with co-morbid antisocial personality disorder (ASPD) have been associated with serotonin (5-HT) dysfunction. 5-HT3 receptors are potentiated by ethanol and appear to modulate reward. 5-HT3 receptor antagonists may be useful in the treatment of early-onset alcoholics with co-morbid ASPD. Low-voltage alpha electroencephalogram (EEG) power, a highly heritable trait, has been associated with both AUD and ASPD. A recent whole genome linkage scan in one of our samples, Plains American Indians (PI), has shown a suggestive linkage peak for alpha power at the 5-HT3R locus. We tested whether genetic variation within the HTR3A and HTR3B genes influences vulnerability to AUD with comorbid ASPD (AUD + ASPD) and moderates alpha power. Our study included three samples: 284 criminal alcoholic Finnish Caucasians and 234 controls; two independent community-ascertained samples with resting EEG recordings: a predominantly Caucasian sample of 191 individuals (Bethesda) and 306 PI. In the Finns, an intronic HTR3B SNP rs3782025 was associated with AUD + ASPD (P = .004). In the Bethesda sample, the same allele predicted lower alpha power (P = 7.37e-5). Associations between alpha power and two other HTR3B SNPs were also observed among PI (P = .03). One haplotype in the haplotype block at the 3′ region of the gene that included rs3782025 was associated with AUD + ASPD in the Finns (P = .02) and with reduced alpha power in the Bethesda population (P = .00009). Another haplotype in this block was associated with alpha power among PI (P = .03). No associations were found for HTR3A. Genetic variation within HTR3B may influence vulnerability to develop AUD with comorbid ASPD. 5-HT3R might contribute to the imbalance between excitation and inhibition that characterize the brain of alcoholics. PMID:19185213

  5. HTR3B is associated with alcoholism with antisocial behavior and alpha EEG power--an intermediate phenotype for alcoholism and co-morbid behaviors.

    PubMed

    Ducci, Francesca; Enoch, Mary-Anne; Yuan, Qiaoping; Shen, Pei-Hong; White, Kenneth V; Hodgkinson, Colin; Albaugh, Bernard; Virkkunen, Matti; Goldman, David

    2009-02-01

    Alcohol use disorders (AUD) with co-morbid antisocial personality disorder (ASPD) have been associated with serotonin (5-HT) dysfunction. 5-HT3 receptors are potentiated by ethanol and appear to modulate reward. 5-HT3 receptor antagonists may be useful in the treatment of early-onset alcoholics with co-morbid ASPD. Low-voltage alpha electroencephalogram (EEG) power, a highly heritable trait, has been associated with both AUD and ASPD. A recent whole genome linkage scan in one of our samples, Plains American Indians (PI), has shown a suggestive linkage peak for alpha power at the 5-HT3R locus. We tested whether genetic variation within the HTR3A and HTR3B genes influences vulnerability to AUD with comorbid ASPD (AUD+ASPD) and moderates alpha power. Our study included three samples: 284 criminal alcoholic Finnish Caucasians and 234 controls; two independent community-ascertained samples with resting EEG recordings: a predominantly Caucasian sample of 191 individuals (Bethesda) and 306 PI. In the Finns, an intronic HTR3B SNP rs3782025 was associated with AUD+ASPD (P=.004). In the Bethesda sample, the same allele predicted lower alpha power (P=7.37e(-5)). Associations between alpha power and two other HTR3B SNPs were also observed among PI (P=.03). One haplotype in the haplotype block at the 3' region of the gene that included rs3782025 was associated with AUD+ASPD in the Finns (P=.02) and with reduced alpha power in the Bethesda population (P=.00009). Another haplotype in this block was associated with alpha power among PI (P=.03). No associations were found for HTR3A. Genetic variation within HTR3B may influence vulnerability to develop AUD with comorbid ASPD. 5-HT3R might contribute to the imbalance between excitation and inhibition that characterize the brain of alcoholics. PMID:19185213

  6. EEG alpha power and creative ideation☆

    PubMed Central

    Fink, Andreas; Benedek, Mathias

    2014-01-01

    Neuroscientific studies revealed first insights into neural mechanisms underlying creativity, but existing findings are highly variegated and often inconsistent. Despite the disappointing picture on the neuroscience of creativity drawn in recent reviews, there appears to be robust evidence that EEG alpha power is particularly sensitive to various creativity-related demands involved in creative ideation. Alpha power varies as a function of creativity-related task demands and the originality of ideas, is positively related to an individuals’ creativity level, and has been observed to increase as a result of creativity interventions. Alpha increases during creative ideation could reflect more internally oriented attention that is characterized by the absence of external bottom-up stimulation and, thus, a form of top-down activity. Moreover, they could indicate the involvement of specific memory processes such as the efficient (re-)combination of unrelated semantic information. We conclude that increased alpha power during creative ideation is among the most consistent findings in neuroscientific research on creativity and discuss possible future directions to better understand the manifold brain mechanisms involved in creativity. PMID:23246442

  7. Relationship of genetically transmitted alpha EEG traits to anxiety disorders and alcoholism

    SciTech Connect

    Enoch, M.A.; Rohrbaugh, W.; Harris, C.R.

    1995-10-09

    We tested the hypothesis that a heritable EEG trait, the low voltage alpha (LV), is associated with psychiatric disorders. Modest to moderate evidence for genetic linkage of both panic disorder and the low voltage alpha trait to the same region of chromosome 20q has recently been reported, raising the issue of whether there is a phenotypic correlation between these traits. A total of 124 subjects including 50 unrelated index subjects and 74 relatives were studied. Alpha EEG power was measured and EEG phenotypes were impressionistically classified. Subjects were psychiatrically interviewed using the SADS-L and blind-rated by RDC criteria. Alcoholics were four times more likely to be LV (including so-called borderline low voltage alpha) than were nonalcoholic, nonanxious subjects. Alcoholics with anxiety disorder are 10 times more likely to be LV. However, alcoholics without anxiety disorder were similar to nonalcoholics in alpha power. An anxiety disorder (panic disorder, phobia, or generalized anxiety) was found in 14/17 LV subjects as compared to 34/101 of the rest of the sample (P < 0.01). Support for these observations was found in the unrelated index subjects in whom no traits would be shared by familial clustering. Lower alpha power in anxiety disorders was not state-dependent, as indicated by the Spielberger Anxiety Scale. Familial covariance of alpha power was 0.25 (P < 0.01). These findings indicate there may be a shared factor underlying the transmissible low voltage alpha EEG variant and vulnerability to anxiety disorders with associated alcoholism. This factor is apparently not rare, because LV was found in approximately 10% of unrelated index subjects and 5% of subjects free of alcoholism and anxiety disorders. 43 refs., 1 fig., 3 tabs.

  8. Abnormality of EEG alpha asymmetry in female adolescent suicide attempters.

    PubMed

    Graae, F; Tenke, C; Bruder, G; Rotheram, M J; Piacentini, J; Castro-Blanco, D; Leite, P; Towey, J

    1996-10-15

    Abnormal electroencephalographic (EEG) activity has been associated with various psychiatric disorders and behaviors, including depression, suicide, and aggression. We examined quantitative resting EEG in Hispanic female adolescent suicide attempters and matched normal controls. Computerized EEG measures were recorded at 11 scalp sites during eyes open and eyes closed periods from 16 suicide attempters and 22 normal controls. Suicide attempters differed from normal controls in alpha asymmetry. Normal adolescents had greater alpha (less activation) over right than left hemisphere, whereas suicidal adolescents had a nonsignificant asymmetry in the opposite direction. Nondepressed attempters were distinguished from depressed attempters in that they accounted for the preponderance of abnormal asymmetry, particularly in posterior regions. Alpha asymmetry over posterior regions was related to ratings of suicidal intent, but not depression severity. The alpha asymmetry in suicidal adolescents resembled that seen for depressed adults in its abnormal direction, but not in its regional distribution. Findings for suicidal adolescents are discussed in terms of a hypothesis of reduced left posterior activation, which is not related to depression but to suicidal or aggressive behavior. PMID:8894062

  9. Frontal Alpha EEG Asymmetry Before and After Behavioral Activation Treatment for Depression

    PubMed Central

    Gollan, Jackie K.; Hoxha, Denada; Chihade, Dietta; Pflieger, Mark E.; Rosebrock, Laina; Cacioppo, John

    2015-01-01

    Background Mid-frontal and mid-lateral (F3/F4 and F7/F8) EEG asymmetry has been associated with motivation and affect. We examined alpha EEG asymmetry in depressed and healthy participants before and after Behavioral Activation treatment for depression; examined the association between alpha EEG asymmetry and motivational systems and affect; and evaluated the utility of alpha EEG asymmetry in predicting remission. Methods Depressed (n = 37) and healthy participants (n = 35) were assessed before and after treatment using a clinical interview, a task to measure baseline EEG, and questionnaires of behavioral activation and inhibition, avoidance, and affect. Results Alpha EEG asymmetry was significantly higher in depressed than healthy participants at pre-treatment, positively correlated with negative affect and behavioral inhibition, and inversely correlated with lower behavioral activation sensitivity. Conclusions Heightened alpha EEG asymmetry in depressed participants was significantly associated with increased behavioral inhibition and negative emotion and was independent of clinical remission. PMID:24674708

  10. Theta and alpha EEG frequency interplay in subjects with mild cognitive impairment: evidence from EEG, MRI, and SPECT brain modifications

    PubMed Central

    Moretti, Davide V.

    2015-01-01

    Background: Temporo-parietal and medial temporal cortex atrophy are associated with mild cognitive impairment (MCI) due to Alzheimer disease (AD) as well as the reduction of regional cerebral blood perfusion in hippocampus. Moreover, the increase of EEG alpha3/alpha2 power ratio has been associated with MCI due to AD and with an increase in theta frequency power in a group of subjects with impaired cerebral perfusion in hippocampus. Methods: Seventy four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording and high resolution 3D magnetic resonance imaging (MRI). Among the patients, a subset of 27 subjects underwent also perfusion single-photon emission computed tomography and hippocampal atrophy evaluation. Alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. Three MCI groups were detected according to increasing tertile values of alpha3/alpha2 power ratio and difference of cortical thickness among the groups estimated. Results: Higher alpha3/alpha2 power ratio group had wider cortical thinning than other groups, mapped to the Supramarginal and Precuneus bilaterally. Subjects with higher alpha3/alpha2 frequency power ratio showed a constant trend to a lower perfusion than lower alpha3/alpha2 group. Moreover, this group correlates with both a bigger hippocampal atrophy and an increase of theta frequency power. Conclusion: Higher EEG alpha3/alpha2 power ratio was associated with temporo-parietal cortical thinning, hippocampal atrophy and reduction of regional cerebral perfusion in medial temporal cortex. In this group an increase of theta frequency power was detected inMCI subjects. The combination of higher EEG alpha3/alpha2 power ratio, cortical thickness measure and regional cerebral perfusion reveals a complex interplay between EEG cerebral rhythms, structural and functional brain modifications. PMID:25926789

  11. Endotoxin enhances EEG alpha and beta power in human sleep.

    PubMed

    Trachsel, L; Schreiber, W; Holsboer, F; Pollmächer, T

    1994-03-01

    Endotoxin, a lipopolysaccharide (0.4 or 0.8 ng/kg body weight), was injected at 1900 hours in 17 healthy men in a single-blind, placebo-controlled experiment. The administration was followed by a 4-hour period of quiet wakefulness in bed (light intensity < 200 lux). Unlimited sleep was allowed after 2300 hours (lights off) until the next morning. The electroencephalogram (EEG), electromyogram, electrooculogram, electrocardiogram and rectal temperature were recorded throughout the experimental session. Standard sleep stages were assessed, and the EEG was submitted to a state-specific, serial spectral analysis. Endotoxin administration induced a rise of body temperature and heart rate, which started approximately 2 hours after the injection and persisted through most of the sleep period. Sleep latency remained unchanged, whereas rapid eye movement (REM) sleep latency increased from 60.3 to 89.0 minutes (paired t test; p = 0.06) compared to control values. Stage 2 sleep was elevated from 45.5 to 49.0% of time in bed (p < 0.05), and total nonrapid eye movement (NREM) sleep from 64.2 to 69.1% (p < 0.05). No significant change could be observed in slow-wave sleep (SWS, stages 3 and 4). During the first 4 hours of the sleep period, NREM sleep EEG spectral power was distinctly and markedly increased between 8 and 12 Hz (alpha) and 15 and 20 Hz (beta) (p < 0.05), whereas at the same time EEG power between 1 and 8 Hz (delta, theta) was not significantly changed. We conclude that in humans the primary host response induced by endotoxin initially suppresses REM sleep and increases stage 2 NREM sleep, but does not affect SWS. No clear modification of sleep EEG delta activity could be observed after endotoxin injection, despite marked endocrinological and physiological changes such as the elevation of body temperature. Numerous factors related to the human primary host response may be responsible for the EEG intensification of the alpha and beta range. PMID:8036367

  12. EEG Alpha Synchronization Is Related to Top-Down Processing in Convergent and Divergent Thinking

    ERIC Educational Resources Information Center

    Benedek, Mathias; Bergner, Sabine; Konen, Tanja; Fink, Andreas; Neubauer, Aljoscha C.

    2011-01-01

    Synchronization of EEG alpha activity has been referred to as being indicative of cortical idling, but according to more recent evidence it has also been associated with active internal processing and creative thinking. The main objective of this study was to investigate to what extent EEG alpha synchronization is related to internal processing…

  13. Alpha-band EEG activity in perceptual learning

    PubMed Central

    Bays, Brett C.; Visscher, Kristina M.; Le Dantec, Christophe C.; Seitz, Aaron R.

    2015-01-01

    In studies of perceptual learning (PL), subjects are typically highly trained across many sessions to achieve perceptual benefits on the stimuli in those tasks. There is currently significant debate regarding what sources of brain plasticity underlie these PL-based learning improvements. Here we investigate the hypothesis that PL, among other mechanisms, leads to task automaticity, especially in the presence of the trained stimuli. To investigate this hypothesis, we trained participants for eight sessions to find an oriented target in a field of near-oriented distractors and examined alpha-band activity, which modulates with attention to visual stimuli, as a possible measure of automaticity. Alpha-band activity was acquired via electroencephalogram (EEG), before and after training, as participants performed the task with trained and untrained stimuli. Results show that participants underwent significant learning in this task (as assessed by threshold, accuracy, and reaction time improvements) and that alpha power increased during the pre-stimulus period and then underwent greater desynchronization at the time of stimulus presentation following training. However, these changes in alpha-band activity were not specific to the trained stimuli, with similar patterns of posttraining alpha power for trained and untrained stimuli. These data are consistent with the view that participants were more efficient at focusing resources at the time of stimulus presentation and are consistent with a greater automaticity of task performance. These findings have implications for PL, as transfer effects from trained to untrained stimuli may partially depend on differential effort of the individual at the time of stimulus processing. PMID:26370167

  14. EEG alpha phase shifts during transition from wakefulness to drowsiness.

    PubMed

    Kalauzi, Aleksandar; Vuckovic, Aleksandra; Bojić, Tijana

    2012-12-01

    Phases of alpha oscillations recorded by EEG were typically studied in the context of event or task related experiments, rarely during spontaneous alpha activity and in different brain states. During wake-to-drowsy transition they change unevenly, depending on the brain region. To explore their dynamics, we recorded ten adult healthy individuals in these two states. Alpha waves were treated as stable frequency and variable amplitude signals with one carrier frequency (CF). A method for calculating their CF phase shifts (CFPS) and CF phase potentials (CFPP) was developed and verified on surrogate signals as more accurate than phase shifts of Fourier components. Probability density estimate (PDE) of CFPS, CFPP and CF phase locking showed that frontal and fronto-temporal areas of the cortex underwent more extensive changes than posterior regions. The greatest differences were found between pairs of channels involving F7, F8, F3 and F4 (PDE of CFPS); F7, F8, T3 and T4 (CFPP); F7, F8, F3, F4, C3, C4 and T3 (decrease in CF phase locking). A topographic distribution of channels with above the average phase locking in the wake state revealed two separate regions occupying anterior and posterior brain areas (with intra regional and inter hemispheric connections). These regions merged and became mutually phase locked longitudinally in the drowsy state. Changes occurring primarily in the frontal and fronto-temporal regions correlated with an early decrease of alertness. Areas of increased phase locking might be correlated with topography of synchronous neuronal assemblies conceptualized within neural correlates of consciousness. PMID:22580156

  15. Spatial correspondence of brain alpha activity component in fMRI and EEG

    NASA Astrophysics Data System (ADS)

    Jeong, Jeong-Won; Kim, Sung-Heon; Singh, Manbir

    2005-04-01

    This paper presents a new approach to investigate the spatial correlation of brain alpha activity in functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). To avoid potential problems of simultaneous fMRI and EEG acquisitions in imaging brain alpha activity, data from each modality were acquired separately under a "three conditions" setup where one of the conditions involved closing eyes and relaxing, thus making it conducive to generation of alpha activity. The other two conditions -- eyes open in a lighted room or engaged in a mental arithmetic task, were designed to attenuate alpha activity. Using the Mixture Density Independent Component Analysis (MD-ICA) that incorporates flexible non-linearity functions into the conventional ICA framework, we could identify the spatiotemporal components of fMRI activations and EEG activities associated with the alpha rhythm. The sources of the individual EEG alpha activity component were localized by a Maximum Entropy (ME) method that solves an inverse problem in the framework of a classical four-sphere head model. The resulting dipole sources of EEG alpha activity were spatially transformed to 3D MRIs of the subject and compared to fMRI ICA-determined alpha activity maps.

  16. CES-D depression scores are correlated with frontal EEG alpha asymmetry.

    PubMed

    Diego, M A; Field, T; Hernandez-Reif, M

    2001-01-01

    In order to evaluate the relationship between frontal EEG asymmetry and depressive symptomology, the Center for Epidemiological Studies Depression scale [CES-D; Radloff, 1977] was given to 163 women, and their EEG was recorded from the mid frontal (F3 and F4) and parietal (P3 and P4) regions during a 3 min baseline recording. As expected from previous research on depression, CES-D scores were negatively correlated with frontal EEG alpha asymmetry scores and positively correlated with left frontal EEG alpha power. Analyses of variance further revealed that mothers scoring above the cut-off for depression (CES-D > or = 16) had significantly lower frontal EEG asymmetry scores than mothers with 0-2 and 3-12 CES-D scores but not lower scores than mothers with 13-15 CES-D scores. PMID:11233458

  17. Clinical and EEG phenotypes of epilepsy in the baboon (Papio hamadryas spp.).

    PubMed

    Szabó, C Akos; Leland, M Michelle; Knape, Koyle; Elliott, James J; Haines, Vicky; Williams, Jeff T

    2005-06-01

    Spontaneous seizures have been reported in several baboon subspecies housed at the Southwest Foundation for Biomedical Research (SFBR), including Papio hamadryas anubis as well as cynocephalus/anubis and other hybrids. This study classified clinical and electroencephalographic (EEG) phenotypes in these subspecies based upon interictal and ictal findings, as well as photosensitivity, by scalp EEG. One hundred baboons underwent 1-h EEG studies with photic stimulation (PS), 49 with previously witnessed seizures and 51 without. The animals were classified according to these electroclinical phenotypes: presence or absence of interictal epileptic discharges (IEDs), seizures and photoparoxysmal or photoconvulsive responses. Effects of age, gender, and species on EEG phenotypes were also examined. Six discrete electroclinical phenotypes were identified. Generalized IEDs of 2-3, 4-6, and/or 6-7Hz were identified in 67 baboons. Epileptic seizures were recorded in 40 animals, including myoclonic and generalized tonic-clonic seizures. Thirty-three animals were photosensitive. Although the prevalence of IEDs and seizures were similar in seizure and asymptomatic animals, photosensitivity was more prevalent in the seizure animals (p=0.001). P.h. anubis/cynocephalus hybrids were more likely to be photosensitive than P.h. anubis (p=0.004). The reliable characterization of distinct epileptic phenotypes in this pedigreed colony is critical to the success of future genetic analyses to identify genetic factors underlying their epilepsy. PMID:15994062

  18. Synergetic fMRI-EEG brain mapping in alpha-rhythm voluntary control mode.

    PubMed

    Shtark, M B; Verevkin, E G; Kozlova, L I; Mazhirina, K G; Pokrovskii, M A; Petrovskii, E D; Savelov, A A; Starostin, A S; Yarosh, S V

    2015-03-01

    For the first time in neurobiology-related issues, the synergistic spatial dynamics of EEG and fMRI (BOLD phenomenon) was studied during cognitive alpha biofeedback training in the operant conditioning mode (acoustic reinforcement of alpha-rhythm development and stability). Significant changes in alpha-rhythm intensity were found in T6 electrode area (Brodmann area 37). Brodmann areas related to solving alpha-training tasks and maximally involved in the formation of new neuronal network were middle and superior temporal gyri (areas 21, 22, and 37), fusiform gyrus, inferior frontal gyrus (areas 4, 6, and 46), anterior cingulate gyrus (areas 23 and 24), cuneus, and precuneus (area 7). Wide involvement of Brodmann areas is determined by psychological architecture of alpha-rhythm generating system control that includes complex cognitive activities: decision making, retrieval of long-term memory, evaluation of the reward and control efficiency during alpha-EEG biofeedback. PMID:25778652

  19. EEG alpha frequency correlates of burnout and depression: The role of gender.

    PubMed

    Tement, Sara; Pahor, Anja; Jaušovec, Norbert

    2016-02-01

    EEG alpha frequency band biomarkers of depression are widely explored. Due to their trait-like features, they may help distinguish between depressive and burnout symptomatology, which is often referred to as "work-related depression". The present correlational study strived to examine whether individual alpha frequency (IAF), power, and coherence in the alpha band can provide evidence for establishing burnout as a separate diagnostic entity. Resting EEG (eyes closed) was recorded in 117 individuals (42 males). In addition, the participants filled-out questionnaires of burnout and depression. Regression analyses highlighted the differential value of IAF and power in predicting burnout and depression. IAF was significantly related to depressive symptomatology, whereas power was linked mostly to burnout. Moreover, seven out of twelve interactions between EEG indicators and gender were significant. Connectivity patterns were significant for depression displaying gender-related differences. The results offer tentative support for establishing burnout as a separate clinical syndrome. PMID:26631352

  20. Mindfulness-of-breathing exercise modulates EEG alpha activity during cognitive performance.

    PubMed

    Bing-Canar, Hanaan; Pizzuto, Jacquelyne; Compton, Rebecca J

    2016-09-01

    The present study investigated whether engaging in a mindful breathing exercise would affect EEG oscillatory activity associated with self-monitoring processes, based on the notion that mindfulness enhances attentional awareness. Participants were assigned to either an audio exercise in mindful breathing or an audio control condition, and then completed a Stroop task while EEG was recorded. The primary EEG measure of interest was error-related alpha suppression (ERAS), an index of self-monitoring in which alpha power is reduced, suggesting mental engagement, following errors compared to correct responses. Participants in the mindful-breathing condition showed increased alpha power during the listening exercise and enhanced ERAS during the subsequent Stroop task. These results indicate enhanced error-monitoring among those in the mindful-breathing group. PMID:27245493

  1. Alpha and beta EEG power reflects L-dopa acute administration in parkinsonian patients

    PubMed Central

    Melgari, Jean-Marc; Curcio, Giuseppe; Mastrolilli, Francesca; Salomone, Gaetano; Trotta, Laura; Tombini, Mario; di Biase, Lazzaro; Scrascia, Federica; Fini, Rita; Fabrizio, Emma; Rossini, Paolo Maria; Vernieri, Fabrizio

    2014-01-01

    Aim: To evaluate the effect of an acute L-dopa administration on eye-closed resting state electroencephalographic (EEG) activity of cognitively preserved Parkinsonian patients. Methods: We examined 24 right-handed patients diagnosed as uncomplicated probable Parkinson’s disease (PD). Each patient underwent Unified Parkinson’s Disease Rating Scale (UPDRS)-part-III evaluation before and 60 min after an oral load of L-dopa-methyl-ester/carbidopa 250/25 mg. Resting condition eyes-closed EEG data were recorded both pre- and post L-dopa load. Absolute EEG power values were calculated at each scalp derivation for Delta, Theta, Alpha and Beta frequency bands. UPDRS scores (both global and subscale scores) and EEG data (power values of different frequency bands for each scalp derivation) were submitted to a statistical analysis to compare Pre and Post L-Dopa conditions. Finally, a correlation analysis was carried out between EEG spectral content and UPDRS scores. Results: Considering EEG power spectral analysis, no statistically significant differences arose on Delta and Theta bands after L-dopa intake. Conversely, Alpha and Beta rhythms significantly increased on centro-parietal scalp derivations, as a function of L-dopa administration. Correlation analysis indicated a significant negative correlation between Beta power increase on centro-parietal areas and UPDRS subscores (Rigidity of arms and Bradykinesia). A minor significant negative correlation was also found between Alpha band increase and resting tremor. Conclusions: Assuming that a significant change in EEG power spectrum after L-dopa intake may be related to dopaminergic mechanisms, our findings are consistent with the hypothesis that dopaminergic defective networks are implicated in cortical oscillatory abnormalities at rest in non-demented PD patients. PMID:25452725

  2. Semi-Automatic Segmentation of Optic Radiations and LGN, and Their Relationship to EEG Alpha Waves

    PubMed Central

    Descoteaux, Maxime; Bernier, Michaël; Garyfallidis, Eleftherios; Whittingstall, Kevin

    2016-01-01

    At rest, healthy human brain activity is characterized by large electroencephalography (EEG) fluctuations in the 8-13 Hz range, commonly referred to as the alpha band. Although it is well known that EEG alpha activity varies across individuals, few studies have investigated how this may be related to underlying morphological variations in brain structure. Specifically, it is generally believed that the lateral geniculate nucleus (LGN) and its efferent fibres (optic radiation, OR) play a key role in alpha activity, yet it is unclear whether their shape or size variations contribute to its inter-subject variability. Given the widespread use of EEG alpha in basic and clinical research, addressing this is important, though difficult given the problems associated with reliably segmenting the LGN and OR. For this, we employed a multi-modal approach and combined diffusion magnetic resonance imaging (dMRI), functional magnetic resonance imaging (fMRI) and EEG in 20 healthy subjects to measure structure and function, respectively. For the former, we developed a new, semi-automated approach for segmenting the OR and LGN, from which we extracted several structural metrics such as volume, position and diffusivity. Although these measures corresponded well with known morphology based on previous post-mortem studies, we nonetheless found that their inter-subject variability was not significantly correlated to alpha power or peak frequency (p >0.05). Our results therefore suggest that alpha variability may be mediated by an alternative structural source and our proposed methodology may in general help in better understanding the influence of anatomy on function such as measured by EEG or fMRI. PMID:27383146

  3. Semi-Automatic Segmentation of Optic Radiations and LGN, and Their Relationship to EEG Alpha Waves.

    PubMed

    Renauld, Emmanuelle; Descoteaux, Maxime; Bernier, Michaël; Garyfallidis, Eleftherios; Whittingstall, Kevin

    2016-01-01

    At rest, healthy human brain activity is characterized by large electroencephalography (EEG) fluctuations in the 8-13 Hz range, commonly referred to as the alpha band. Although it is well known that EEG alpha activity varies across individuals, few studies have investigated how this may be related to underlying morphological variations in brain structure. Specifically, it is generally believed that the lateral geniculate nucleus (LGN) and its efferent fibres (optic radiation, OR) play a key role in alpha activity, yet it is unclear whether their shape or size variations contribute to its inter-subject variability. Given the widespread use of EEG alpha in basic and clinical research, addressing this is important, though difficult given the problems associated with reliably segmenting the LGN and OR. For this, we employed a multi-modal approach and combined diffusion magnetic resonance imaging (dMRI), functional magnetic resonance imaging (fMRI) and EEG in 20 healthy subjects to measure structure and function, respectively. For the former, we developed a new, semi-automated approach for segmenting the OR and LGN, from which we extracted several structural metrics such as volume, position and diffusivity. Although these measures corresponded well with known morphology based on previous post-mortem studies, we nonetheless found that their inter-subject variability was not significantly correlated to alpha power or peak frequency (p >0.05). Our results therefore suggest that alpha variability may be mediated by an alternative structural source and our proposed methodology may in general help in better understanding the influence of anatomy on function such as measured by EEG or fMRI. PMID:27383146

  4. Biofeedback Auditory Alpha EEG Training and Its Effect upon Anxiety and Reading Achievement.

    ERIC Educational Resources Information Center

    Lally, Marianne B.

    The major purpose of this exploratory study was to determine if electroencephalographic (EEG) auditory biofeedback training combined with Open Focus relaxation therapy would increase alpha-brain-wave production in highly anxious freshman university students who were also deficient in reading skills. The subjects for the study were 15 volunteer…

  5. Differences in EEG Alpha Activity between Gifted and Non-Identified Individuals: Insights into Problem Solving.

    ERIC Educational Resources Information Center

    Jausovec, Norbert

    1997-01-01

    This study examined differences in electroencephalography (EEG) alpha activity between gifted and nongifted Slovenian student-teachers (N=17 each). Gifted students showed greater left hemisphere activation than nongifted subjects in relaxed states, but lower activation during problem solving. The same pattern was observed in overall hemispheric…

  6. EEG alpha asymmetry in schizophrenia, depression, PTSD, panic disorder, ADHD and conduct disorder.

    PubMed

    Gordon, Evian; Palmer, Donna M; Cooper, Nicholas

    2010-10-01

    Models of laterality infer distinct aspects of EEG alpha asymmetry in clinical disorders, which has been replicated for over three decades. This biomarker now requires a more fine-grained assessment of its clinical utility as a diagnostic and treatment predictive marker. Here, within the same study we assessed resting brain laterality across six clinical disorders, for which deviant laterality has been implicated as core dysfunction. These disorders were evaluated in comparison to a large normative dataset (approximately 1,900) from the Brain Resource International Database. EEG alpha asymmetry was assessed in the frontocentral region, for resting Eyes Closed and Eyes Open conditions. Schizophrenia was characterized by significantly greater left lateralized alpha power than controls, indicating a deficit in left frontal activity at rest, which may relate to "disconnections" across wider fronto-temporal networks. The depression group showed a trend-level tendency towards the opposite pattern of greater right-lateralized activity than controls. The remaining anxiety and behavioral disorders did not show any significant deviance in alpha asymmetry from the normative control group. However, at a non-significant level laterality for these groups was generally consistent with expected directions, suggesting a propensity towards a particular lateralization but still remaining within the normative range. Overall, the results of the current study indicate that EEG alpha asymmetry may show the most clinical utility as a biomarker for schizophrenia and depression in comparison to other clinical disorders. PMID:21077569

  7. [Slow alpha in the EEG power spectrum as an indicator for conceptual arousal].

    PubMed

    Bösel, R

    1992-01-01

    Based on previous findings (Bösel et al., 1990) it was assumed that in concept learning tasks generating on hypotheses on a concept which has to be developed is accompanied by increases of the Alpha 1 power (7.5-10 Hz) in the spontaneous EEG activity. In this study 16 subjects performed five problem solving tasks with similar processing requirements. EEG data were analyzed by means of post hoc comparisons of subjects differing in performance quality. Additionally, four control tasks were employed in which, based on previous studies, variations in the Theta frequency range were expected. An effect in the Alpha 1 frequency band was observed in tasks requiring reconstructive recall or testing the usefulness of an mathematical algorithm. The creation of a rank order or mental map is accompanied by power increases in the lower portions of the Alpha 1 frequency band (7.5-8.5 Hz). Moreover a high amount of controlled variance (eta2 up to 34%) was obtained for this effect. Increases in EEG Theta power, which presumably indicate subjects' component analysis, were found before the subjects recognized parts of geometric figures or before relevant features in the "buddhist monk problem" were discriminated. The dynamics of EEG power over time is in examples of frequency/time plots in a figure, illustrated. PMID:1441650

  8. EEG

    MedlinePlus

    ... is also used to: Evaluate problems with sleep ( sleep disorders ) Monitor the brain during brain surgery An EEG ... in some cases) Seizure disorder (such as epilepsy) Sleep disorder (such as narcolepsy ) Swelling of the brain (edema)

  9. EEG

    MedlinePlus

    ... is also used to: Evaluate problems with sleep ( sleep disorders ) Monitor the brain during brain surgery An EEG ... in some cases) Seizure disorder (such as epilepsy) Sleep disorder (such as narcolepsy ) Swelling of the brain (edema) ...

  10. Mobile phone emission modulates interhemispheric functional coupling of EEG alpha rhythms.

    PubMed

    Vecchio, Fabrizio; Babiloni, Claudio; Ferreri, Florinda; Curcio, Giuseppe; Fini, Rita; Del Percio, Claudio; Rossini, Paolo Maria

    2007-03-01

    We tested the working hypothesis that electromagnetic fields from mobile phones (EMFs) affect interhemispheric synchronization of cerebral rhythms, an important physiological feature of information transfer into the brain. Ten subjects underwent two electroencephalographic (EEG) recordings, separated by 1 week, following a crossover double-blind paradigm in which they were exposed to a mobile phone signal (global system for mobile communications; GSM). The mobile phone was held on the left side of the subject head by a modified helmet, and orientated in the normal position for use over the ear. The microphone was orientated towards the corner of the mouth, and the antenna was near the head in the parietotemporal area. In addition, we positioned another similar phone (but without battery) on the right side of the helmet, to balance the weight and to prevent the subject localizing the side of GSM stimulation (and consequently lateralizing attention). In one session the exposure was real (GSM) while in the other it was Sham; both sessions lasted 45 min. Functional interhemispheric connectivity was modelled using the analysis of EEG spectral coherence between frontal, central and parietal electrode pairs. Individual EEG rhythms of interest were delta (about 2-4 Hz), theta (about 4-6 Hz), alpha 1 (about 6-8 Hz), alpha 2 (about 8-10 Hz) and alpha 3 (about 10-12 Hz). Results showed that, compared to Sham stimulation, GSM stimulation modulated the interhemispheric frontal and temporal coherence at alpha 2 and alpha 3 bands. The present results suggest that prolonged mobile phone emission affects not only the cortical activity but also the spread of neural synchronization conveyed by interhemispherical functional coupling of EEG rhythms. PMID:17432975

  11. Prefrontal EEG alpha asymmetry changes while observing disaster happening to other people: cardiac correlates and prediction of emotional impact.

    PubMed

    Papousek, Ilona; Weiss, Elisabeth M; Schulter, Günter; Fink, Andreas; Reiser, Eva M; Lackner, Helmut K

    2014-12-01

    Changes of EEG alpha asymmetry in terms of increased right versus left sided activity in prefrontal cortex are considered to index activation of the withdrawal/avoidance motivational system. The present study aimed to add evidence of the validity of individual differences in the EEG alpha asymmetry response and their relevance regarding the impact of emotional events. The magnitude of the EEG alpha asymmetry response while watching a film consisting of scenes of real injury and death correlated with components of transient cardiac responses to sudden horrifying events happening to persons in the film which index withdrawal/avoidance motivation and heightened attention and perceptual intake. Additionally, it predicted greater mood deterioration following the film and film-related intrusive memories and avoidance over the following week. The study provides further evidence for prefrontal EEG alpha asymmetry changes in response to relevant stimuli reflecting an individual's sensitivity to negative social-emotional cues encountered in everyday life. PMID:25224180

  12. Interval analysis of interictal EEG: pathology of the alpha rhythm in focal epilepsy

    NASA Astrophysics Data System (ADS)

    Pyrzowski, Jan; Siemiński, Mariusz; Sarnowska, Anna; Jedrzejczak, Joanna; Nyka, Walenty M.

    2015-11-01

    The contemporary use of interictal scalp electroencephalography (EEG) in the context of focal epilepsy workup relies on the visual identification of interictal epileptiform discharges. The high-specificity performance of this marker comes, however, at a cost of only moderate sensitivity. Zero-crossing interval analysis is an alternative to Fourier analysis for the assessment of the rhythmic component of EEG signals. We applied this method to standard EEG recordings of 78 patients divided into 4 subgroups: temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE), psychogenic nonepileptic seizures (PNES) and nonepileptic patients with headache. Interval-analysis based markers were capable of effectively discriminating patients with epilepsy from those in control subgroups (AUC~0.8) with diagnostic sensitivity potentially exceeding that of visual analysis. The identified putative epilepsy-specific markers were sensitive to the properties of the alpha rhythm and displayed weak or non-significant dependences on the number of antiepileptic drugs (AEDs) taken by the patients. Significant AED-related effects were concentrated in the theta interval range and an associated marker allowed for identification of patients on AED polytherapy (AUC~0.9). Interval analysis may thus, in perspective, increase the diagnostic yield of interictal scalp EEG. Our findings point to the possible existence of alpha rhythm abnormalities in patients with epilepsy.

  13. Spontaneous Slow Fluctuation of EEG Alpha Rhythm Reflects Activity in Deep-Brain Structures: A Simultaneous EEG-fMRI Study

    PubMed Central

    Omata, Kei; Hanakawa, Takashi; Morimoto, Masako; Honda, Manabu

    2013-01-01

    The emergence of the occipital alpha rhythm on brain electroencephalogram (EEG) is associated with brain activity in the cerebral neocortex and deep brain structures. To further understand the mechanisms of alpha rhythm power fluctuation, we performed simultaneous EEGs and functional magnetic resonance imaging recordings in human subjects during a resting state and explored the dynamic relationship between alpha power fluctuation and blood oxygenation level-dependent (BOLD) signals of the brain. Based on the frequency characteristics of the alpha power time series (APTS) during 20-minute EEG recordings, we divided the APTS into two components: fast fluctuation (0.04–0.167 Hz) and slow fluctuation (0–0.04 Hz). Analysis of the correlation between the MRI signal and each component revealed that the slow fluctuation component of alpha power was positively correlated with BOLD signal changes in the brain stem and the medial part of the thalamus and anterior cingulate cortex, while the fast fluctuation component was correlated with the lateral part of the thalamus and the anterior cingulate cortex, but not the brain stem. In summary, these data suggest that different subcortical structures contribute to slow and fast modulations of alpha spectra on brain EEG. PMID:23824708

  14. Neonatal EEG/sleep state analyses: a complex phenotype of developmental neural plasticity.

    PubMed

    Scher, Mark S; Loparo, Kenneth A

    2009-01-01

    Computer analyses of EEG/sleep states can be used as physiologic biomarkers of developmental neural plasticity. Frequency- and time-dependent signal processing strategies of cerebral and noncerebral measures can help test current theories of neuronal network maturation in terms of segregation and integration of short-distance versus long-distance neuronal connections throughout the neuroaxis. Specific phenotypic expressions of adaptive or maladaptive neuronal connectivity are proposed based on comparisons of whole-brain EEG/sleep resting states between preterm and full-term cohorts when developmental outcome measures are applied. Combined use of neurophysiological datasets with neuroimaging and genetic methodologies define endophenotypes that will more accurately diagnose children at risk for developmental disorders, as well as design appropriate neuroprotective interventions for the individual's age and disease progress. PMID:19546563

  15. EEG Alpha and Beta Activity in Normal and Deaf Subjects.

    ERIC Educational Resources Information Center

    Waldron, Manjula; And Others

    Electroencephalogram and task performance data were collected from three groups of young adult males: profoundly deaf Ss who signed from an early age, profoundly deaf Ss who only used oral (speech and speedreading) methods of communication, and normal hearing Ss. Alpha and Beta brain wave patterns over the Wernicke's area were compared across…

  16. A novel EEG for alpha brain state training, neurobiofeedback and behavior change.

    PubMed

    Stinson, Bruce; Arthur, David

    2013-08-01

    Mindfulness meditation, with the resulting alpha brain state, is gaining a strong following as an adjunct to health, so too is applying self-affirmation to stimulate behavior change through subconscious re-programming. Until recently the EEG technology needed to demonstrate this has been cumbersome and required specialist training. This paper reports a pilot study using a remote EEG headband, which through a sophisticated algorithm, provides a real-time EEG readout unencumbered by conventional artifacts. In a convenience sample of 13, the difference in brain waves was examined while the subjects were occupied in an 'attention' and an 'alpha mind state' exercise. There was a significant difference in the mean scores for theta, delta, beta and gamma brain waves. Alpha brain waves remained static suggesting an ability of the headset to discriminate a mindful state and to provide real-time, easy to interpret feedback for the facilitator and subject. The findings provide encouragement for research applications in health care activities providing neurobiofeedback to subjects involved in mindfulness behavior change activities. PMID:23890456

  17. Brain correlates underlying creative thinking: EEG alpha activity in professional vs. novice dancers.

    PubMed

    Fink, Andreas; Graif, Barbara; Neubauer, Aljoscha C

    2009-07-01

    Neuroscientific research on creativity has revealed valuable insights into possible brain correlates underlying this complex mental ability domain. However, most of the studies investigated brain activity during the performance of comparatively simple (verbal) type of tasks and the majority of studies focused on samples of the normal population. In this study we investigate EEG activity in professional dancers (n=15) who have attained a high level of expertise in this domain. This group was compared with a group of novices (n=17) who have only basic experience in dancing and completed no comprehensive training in this field. The EEG was recorded during performance of two different dancing imagery tasks which differed with respect to creative demands. In the first task participants were instructed to mentally perform a dance which should be as unique and original as possible (improvisation dance). In the waltz task they were asked to imagine dancing the waltz, a standard dance which involves a sequence of monotonous steps (lower creative demands). In addition, brain activity was also measured during performance of the Alternative Uses test. We observed evidence that during the generation of alternative uses professional dancers show stronger alpha synchronization in posterior parietal brain regions than novice dancers. During improvisation dance, professional dancers exhibited more right-hemispheric alpha synchronization than the group of novices did, while during imagining dancing the waltz no significant group differences emerged. The findings complement and extend existing findings on the relationship between EEG alpha activity and creative thinking. PMID:19269335

  18. Dynamics of alpha control: preparatory suppression of posterior alpha oscillations by frontal modulators revealed with combined EEG and event-related optical signal.

    PubMed

    Mathewson, Kyle E; Beck, Diane M; Ro, Tony; Maclin, Edward L; Low, Kathy A; Fabiani, Monica; Gratton, Gabriele

    2014-10-01

    We investigated the dynamics of brain processes facilitating conscious experience of external stimuli. Previously, we proposed that alpha (8-12 Hz) oscillations, which fluctuate with both sustained and directed attention, represent a pulsed inhibition of ongoing sensory brain activity. Here we tested the prediction that inhibitory alpha oscillations in visual cortex are modulated by top-down signals from frontoparietal attention networks. We measured modulations in phase-coherent alpha oscillations from superficial frontal, parietal, and occipital cortices using the event-related optical signal (EROS), a measure of neuronal activity affording high spatiotemporal resolution, along with concurrently recorded EEG, while participants performed a visual target detection task. The pretarget alpha oscillations measured with EEG and EROS from posterior areas were larger for subsequently undetected targets, supporting alpha's inhibitory role. Using EROS, we localized brain correlates of these awareness-related alpha oscillations measured at the scalp to the cuneus and precuneus. Crucially, EROS alpha suppression correlated with posterior EEG alpha power across participants. Sorting the EROS data based on EEG alpha power quartiles to investigate alpha modulators revealed that suppression of posterior alpha was preceded by increased activity in regions of the dorsal attention network and decreased activity in regions of the cingulo-opercular network. Cross-correlations revealed the temporal dynamics of activity within these preparatory networks before posterior alpha modulation. The novel combination of EEG and EROS afforded localization of the sources and correlates of alpha oscillations and their temporal relationships, supporting our proposal that top-down control from attention networks modulates both posterior alpha and awareness of visual stimuli. PMID:24702458

  19. The validity of individual frontal alpha asymmetry EEG neurofeedback.

    PubMed

    Quaedflieg, C W E M; Smulders, F T Y; Meyer, T; Peeters, F; Merckelbach, H; Smeets, T

    2016-01-01

    Frontal asymmetry in alpha oscillations is assumed to be associated with psychopathology and individual differences in emotional responding. Brain-activity-based feedback is a promising tool for the modulation of cortical activity. Here, we validated a neurofeedback protocol designed to change relative frontal asymmetry based on individual alpha peak frequencies, including real-time average referencing and eye-correction. Participants (N = 60) were randomly assigned to a right, left or placebo neurofeedback group. Results show a difference in trainability between groups, with a linear change in frontal alpha asymmetry over time for the right neurofeedback group during rest. Moreover, the asymmetry changes in the right group were frequency and location specific, even though trainability did not persist at 1 week and 1 month follow-ups. On the behavioral level, subjective stress on the second test day was reduced in the left and placebo neurofeedback groups, but not in the right neurofeedback group. We found individual differences in trainability that were dependent on training group, with participants in the right neurofeedback group being more likely to change their frontal asymmetry in the desired direction. Individual differences in trainability were also reflected in the ability to change frontal asymmetry during the feedback. PMID:26163671

  20. Posterior EEG alpha at rest and during task performance: Comparison of current source density and field potential measures

    PubMed Central

    Tenke, Craig E.; Kayser, Jürgen; Abraham, Karen; Alvarenga, Jorge E.; Bruder, Gerard E.

    2015-01-01

    Resting and task-related EEG alpha are used in studies of cognition and psychopathogy. Although Laplacian methods have been applied, apprehensions about loss of global activity dissuade researchers from greater use except as a supplement to reference-dependent measures. The unfortunate result has been continued reliance on reference strategies that differ across labs, and a systemic preference for a montage-dependent average reference over true reference-free measures. We addressed these concerns by comparing resting- and task-related EEG alpha using three EEG transformations: nose- (NR) and average-referenced (AR) EEG, and the corresponding CSD. Amplitude spectra of resting and prestimulus task-related EEG (novelty oddball) and event-related spectral perturbations were scaled to equate each transformation. Alpha measures quantified for 8-12 Hz bands were: 1) net amplitude (eyes-closed minus eyes-open) and 2) overall amplitude (eyes-closed plus eyes-open); 3) task amplitude (prestimulus baseline) and 4) task event-related desynchronization (ERD). Mean topographies unambiguously represented posterior alpha for overall, net and task, as well as poststimulus alpha ERD. Topographies were similar for the three transformations, but differed in dispersion, CSD being sharpest and NR most broadly distributed. Transformations also differed in scale, AR showing less attenuation or spurious secondary maxima at anterior sites, consistent with simulations of distributed posterior generators. Posterior task alpha and alpha ERD were positively correlated with overall alpha, but not with net alpha. CSD topographies consistently and appropriately represented posterior EEG alpha for all measures. PMID:26026372

  1. Contribution of neurophysiological endophenotype, individual frequency of EEG alpha oscillations, to mechanisms of emotional reactivity.

    PubMed

    Tumyalis, A V; Aftanas, L I

    2014-04-01

    We studied the relationship between individual alpha frequency (IAF) of EEG (neurophysiological endophenotype reflecting individual predisposition to efficacious cognitive and creative activity) and individual emotional reactivity. The psychophysiological study included healthy men in two models of evoked emotions - anxious apprehension (awaiting of inescapable aversive punishment) and discrete (opposite) emotions. Analysis of self-report, multichannel EEG, galvanic skin response, and cardiovascular reactivity showed that individuals with high IAF are characterized by predominance of parasympathetic influences in autonomic regulation circuit, proactive strategies of coping with inescapable threat, higher activity of positive emotional attitude and availability of memory traces about positive experience. Individuals with low IAF demonstrate predominance of sympathetic influences and maladaptive avoidance-like coping with inescapable threat and insufficiency of positive emotional activation mechanisms. It is suggested that IAF participates in the formation of individual emotional space and strategies of coping with emotional challenges. PMID:24824678

  2. Correlations between personality traits and specific groups of alpha waves in the human EEG

    PubMed Central

    2016-01-01

    Background. Different individuals have alpha waves with different wavelengths. The distribution of the wavelengths is assumed to be bell-shaped and smooth. Although this view is generally accepted, it is still just an assumption and has never been critically tested. When exploring the relationship between alpha waves and personality traits, it makes a huge difference if the distribution of the alpha waves is smooth or if specific groups of alpha waves can be demonstrated. Previous studies have not considered the possibility that specific groups of alpha waves may exist. Methods. Computerized EEGs have become standard, but wavelength measurements are problematic when based on averaging procedures using the Fourier transformation because such procedures cause a large systematic error. If the actual wavelength is of interest, it is necessary to go back to basic physiology and use raw EEG signals. In the present study, measurements were made directly from sequences of alpha waves where every wave could be identified. Personality dimensions were measured using an inventory derived from the International Personality Item Pool. Results. Recordings from 200 healthy individuals revealed that there are three main groups of alpha waves. These groups had frequencies around 8, 10, and 12 waves per second. The middle group had a bimodal distribution, and a subdivision gave a total of four alpha groups. In the center of each group, the degree of extraversion was high and the degree of neuroticism was low. Many small differences in personality traits were found when the centers were compared with one another. This gave four personality profiles that resemble the four classical temperaments. When people in the surrounding zones were compared with those in the centers, relatively large differences in personality traits were found. Conclusions. Specific groups of alpha waves exist, and these groups have to be taken into account when correlations are made to personality dimensions and

  3. Correlations between personality traits and specific groups of alpha waves in the human EEG.

    PubMed

    Johannisson, Tomas

    2016-01-01

    Background. Different individuals have alpha waves with different wavelengths. The distribution of the wavelengths is assumed to be bell-shaped and smooth. Although this view is generally accepted, it is still just an assumption and has never been critically tested. When exploring the relationship between alpha waves and personality traits, it makes a huge difference if the distribution of the alpha waves is smooth or if specific groups of alpha waves can be demonstrated. Previous studies have not considered the possibility that specific groups of alpha waves may exist. Methods. Computerized EEGs have become standard, but wavelength measurements are problematic when based on averaging procedures using the Fourier transformation because such procedures cause a large systematic error. If the actual wavelength is of interest, it is necessary to go back to basic physiology and use raw EEG signals. In the present study, measurements were made directly from sequences of alpha waves where every wave could be identified. Personality dimensions were measured using an inventory derived from the International Personality Item Pool. Results. Recordings from 200 healthy individuals revealed that there are three main groups of alpha waves. These groups had frequencies around 8, 10, and 12 waves per second. The middle group had a bimodal distribution, and a subdivision gave a total of four alpha groups. In the center of each group, the degree of extraversion was high and the degree of neuroticism was low. Many small differences in personality traits were found when the centers were compared with one another. This gave four personality profiles that resemble the four classical temperaments. When people in the surrounding zones were compared with those in the centers, relatively large differences in personality traits were found. Conclusions. Specific groups of alpha waves exist, and these groups have to be taken into account when correlations are made to personality dimensions and

  4. Brief Report: Reduced Temporal-Central EEG Alpha Coherence During Joint Attention Perception in Adolescents with Autism Spectrum Disorder.

    PubMed

    Jaime, Mark; McMahon, Camilla M; Davidson, Bridget C; Newell, Lisa C; Mundy, Peter C; Henderson, Heather A

    2016-04-01

    Although prior studies have demonstrated reduced resting state EEG coherence in adults with autism spectrum disorder (ASD), no studies have explored the nature of EEG coherence during joint attention. We examined the EEG coherence of the joint attention network in adolescents with and without ASD during congruent and incongruent joint attention perception and an eyes-open resting condition. Across conditions, adolescents with ASD showed reduced right hemisphere temporal-central alpha coherence compared to typically developing adolescents. Greater right temporal-central alpha coherence during joint attention was positively associated with social cognitive performance in typical development but not in ASD. These results suggest that, in addition to a resting state, EEG coherence during joint attention perception is reduced in ASD. PMID:26659813

  5. Data-driven analysis of simultaneous EEG/fMRI reveals neurophysiological phenotypes of impulse control.

    PubMed

    Schmüser, Lena; Sebastian, Alexandra; Mobascher, Arian; Lieb, Klaus; Feige, Bernd; Tüscher, Oliver

    2016-09-01

    Response inhibition is the ability to suppress inadequate but prepotent or ongoing response tendencies. A fronto-striatal network is involved in these processes. Between-subject differences in the intra-individual variability have been suggested to constitute a key to pathological processes underlying impulse control disorders. Single-trial EEG/fMRI analysis allows to increase sensitivity for inter-individual differences by incorporating intra-individual variability. Thirty-eight healthy subjects performed a visual Go/Nogo task during simultaneous EEG/fMRI. Of 38 healthy subjects, 21 subjects reliably showed Nogo-related ICs (Nogo-IC-positive) while 17 subjects (Nogo-IC-negative) did not. Comparing both groups revealed differences on various levels: On trait level, Nogo-IC-negative subjects scored higher on questionnaires regarding attention deficit/hyperactivity disorder; on a behavioral level, they displayed slower response times (RT) and higher intra-individual RT variability while both groups did not differ in their inhibitory performance. On the neurophysiological level, Nogo-IC-negative subjects showed a hyperactivation of left inferior frontal cortex/insula and left putamen as well as significantly reduced P3 amplitudes. Thus, a data-driven approach for IC classification and the resulting presence or absence of early Nogo-specific ICs as criterion for group selection revealed group differences at behavioral and neurophysiological levels. This may indicate electrophysiological phenotypes characterized by inter-individual variations of neural and behavioral correlates of impulse control. We demonstrated that the inter-individual difference in an electrophysiological correlate of response inhibition is correlated with distinct, potentially compensatory neural activity. This may suggest the existence of electrophysiologically dissociable phenotypes of behavioral and neural motor response inhibition with the Nogo-IC-positive phenotype possibly providing

  6. Relation of EEG alpha background to cognitive fuction, brain atrophy, and cerebral metabolism in Down's syndrome. Age-specific changes

    SciTech Connect

    Devinsky, O.; Sato, S.; Conwit, R.A.; Schapiro, M.B. )

    1990-01-01

    We studied 19 young adults (19 to 37 years old) and 9 older patients (42 to 66 years old) with Down's syndrome (DS) and a control group of 13 healthy adults (22 to 38 years old) to investigate the relation of electroencephalographic (EEG) alpha background to cognitive function and cerebral metabolism. Four of the older patients with DS had a history of mental deterioration, disorientation, and memory loss and were demented. Patients and control subjects had EEGs, psychometric testing, quantitative computed tomography, and positron emission tomography with fludeoxyglucose F 18. A blinded reader classified the EEGs into two groups--those with normal alpha background or those with abnormal background. All the control subjects, the 13 young adult patients with DS, and the 5 older patients with DS had normal EEG backgrounds. In comparison with the age-matched patients with DS with normal alpha background, older patients with DS with decreased alpha background had dementia, fewer visuospatial skills, decreased attention span, larger third ventricles, and a global decrease in cerebral glucose utilization with parietal hypometabolism. In the young patients with DS, the EEG background did not correlate with psychometric or positron emission tomographic findings, but the third ventricles were significantly larger in those with abnormal EEG background. The young patients with DS, with or without normal EEG background, had positron emission tomographic findings similar to those of the control subjects. The mechanism underlying the abnormal EEG background may be the neuropathologic changes of Alzheimer's disease in older patients with DS and may be cerebral immaturity in younger patients with DS.

  7. Detecting Driver Mental Fatigue Based on EEG Alpha Power Changes during Simulated Driving

    PubMed Central

    GHARAGOZLOU, Faramarz; NASL SARAJI, Gebraeil; MAZLOUMI, Adel; NAHVI, Ali; MOTIE NASRABADI, Ali; RAHIMI FOROUSHANI, Abbas; ARAB KHERADMAND, Ali; ASHOURI, Mohammadreza; SAMAVATI, Mehdi

    2015-01-01

    Background: Driver fatigue is one of the major implications in transportation safety and accounted for up to 40% of road accidents. This study aimed to analyze the EEG alpha power changes in partially sleep-deprived drivers while performing a simulated driving task. Methods: Twelve healthy male car drivers participated in an overnight study. Continuous EEG and EOG records were taken during driving on a virtual reality simulator on a monotonous road. Simultaneously, video recordings from the driver face and behavior were performed in lateral and front views and rated by two trained observers. Moreover, the subjective self-assessment of fatigue was implemented in every 10-min interval during the driving using Fatigue Visual Analog Scale (F-VAS). Power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. Results: The findings showed a significant increase in the absolute alpha power (P = 0.006) as well as F-VAS scores during the final section of driving (P = 0.001). Meanwhile, video ratings were consistent with subjective self-assessment of fatigue. Conclusion: The increase in alpha power in the final section of driving indicates the decrease in the level of alertness and attention and the onset of fatigue, which was consistent with F-VAS and video ratings. The study suggested that variations in alpha power could be a good indicator for driver mental fatigue, but for using as a countermeasure device needed further investigations. PMID:26811821

  8. Individual differences in EEG theta and alpha dynamics during working memory correlate with fMRI responses across subjects

    PubMed Central

    Meltzer, Jed A.; Negishi, Michiro; Mayes, Linda C.; Constable, R. Todd

    2007-01-01

    Objective Theta and alpha range EEG oscillations are commonly induced in cognitive tasks, but their possible relationship to the BOLD signal of fMRI is not well understood, and individual variability is high. We explored individual differences in EEG reactivity to determine whether it is positively or negatively correlated with BOLD across subjects. Methods A Sternberg working memory task with 2, 4, or 6 digits was administered to 18 subjects in separate fMRI and EEG sessions. Memory load dependent theta and alpha reactivity was quantified and used as a regressor to reveal brain areas exhibiting EEG-fMRI correlation across subjects. Results Theta increases localized to medial prefrontal cortex, and correlated negatively with BOLD in that region and in other “default mode” areas. Alpha modulation localized to parietal-occipital midline cortex and also correlated negatively with BOLD. Conclusions Individual tendencies to exhibit memory-load dependent oscillations are associated with negative BOLD responses certain brain regions. Significance Positive BOLD responses and increased EEG oscillations do not necessarily arise in the same regions. Negative BOLD responses may also relate to cognitive activity, as traditionally indexed by increased EEG power in the theta band. PMID:17900976

  9. Determination of human EEG alpha entrainment ERD/ERS using the continuous complex wavelet transform

    NASA Astrophysics Data System (ADS)

    Chorlian, David B.; Porjesz, Bernice; Begleiter, Henri

    2003-04-01

    Alpha entrainment caused by exposure to a background stimulus continuously flickering at a rate of 8 1/3 Hz was affected by the appearance of a foreground target stimulus to which the subjects were requested to press a button. With the use of bipolar derivations (to reduce volume conduction effects), scalp recorded EEG potentials were subjected to a continuous wavelet transform using complex Morlet wavelets at a range of scales. Complex Morlet wavelets were used to calculate efficiently instantaneous amplitudes and phases on a per-trial basis, rather than using the Hilbert transform on band-pass filtered data. Multiple scales were employed to contrast the pattern of alpha activity with those in other bands, and to determine whether the harmonics observed in the spectral analysis of the data were simply a result of the non-sinusoidal response to the entraining signal or a distinct neural phenomenon. We were thus able to calculate desynchronization/resynchronization for both the entrained and non-entrained alpha activity. The occurance of the target stimulus caused a sharp increase in amplitude in both the entrained and non-entrained alpha activity, followed by a sharp decrease, and then a return to baseline, over a period of 2.5 seconds. However, the entrained alpha activity showed a much more rapid recovery than non-entrained activity.

  10. Supine posture inhibits cortical activity: Evidence from Delta and Alpha EEG bands.

    PubMed

    Spironelli, Chiara; Busenello, Jessica; Angrilli, Alessandro

    2016-08-01

    Past studies have shown consistent evidence that body position significantly affects brain activity, revealing that both head-down and horizontal bed-rest are associated with cortical inhibition and altered perceptual and cognitive processing. The present study investigates the effects of body position on spontaneous, open-eyes, resting-state EEG cortical activity in 32 young women randomly assigned to one of two conditions, seated position (SP) or horizontal bed rest (BR). A between-group repeated-measure experimental design was used, EEG recordings were made from 38 scalp locations, and low-frequency (delta and alpha) amplitudes of the two groups were compared in four different conditions: when both groups (a) were seated (T0), (b) assumed two different body positions (seated vs. supine conditions, immediate [T1] and 120min later [T2]), and (c) were seated again (T3). Overall, the results showed no a priori between-group differences (T0) before experimental manipulation. As expected, delta amplitude, an index of cortical inhibition in awake resting participants, was significantly increased in group BR, revealing both rapid (T1) and mid-term (T2) inhibitory effects of supine or horizontal positions. Instead, the alpha band was highly sensitive to postural transitions, perhaps due to baroreceptor intervention and, unlike the delta band, underwent habituation and decreased after a 2-h bed rest. These results indicate clear-cut differences at rest between the seated and supine positions, thus supporting the view that the role of body position in the differences found between brain metabolic methods (fMRI and PET) in which participants lie horizontally, and EEG-MEG-TMS techniques with participants in a seated position, has been largely underestimated so far. PMID:27312745

  11. EEG Alpha and Gamma Modulators Mediate Motion Sickness-Related Spectral Responses.

    PubMed

    Chuang, Shang-Wen; Chuang, Chun-Hsiang; Yu, Yi-Hsin; King, Jung-Tai; Lin, Chin-Teng

    2016-03-01

    Motion sickness (MS) is a common experience of travelers. To provide insights into brain dynamics associated with MS, this study recruited 19 subjects to participate in an electroencephalogram (EEG) experiment in a virtual-reality driving environment. When riding on consecutive winding roads, subjects experienced postural instability and sensory conflict between visual and vestibular stimuli. Meanwhile, subjects rated their level of MS on a six-point scale. Independent component analysis (ICA) was used to separate the filtered EEG signals into maximally temporally independent components (ICs). Then, reduced logarithmic spectra of ICs of interest, using principal component analysis, were decomposed by ICA again to find spectrally fixed and temporally independent modulators (IMs). Results demonstrated that a higher degree of MS accompanied increased activation of alpha (r = 0.421) and gamma (r =0.478) IMs across remote-independent brain processes, covering motor, parietal and occipital areas. This co-modulatory spectral change in alpha and gamma bands revealed the neurophysiological demand to regulate conflicts among multi-modal sensory systems during MS. PMID:26790485

  12. Topographic distribution of EEG alpha attractor correlation dimension values in wake and drowsy states in humans.

    PubMed

    Kalauzi, Aleksandar; Vuckovic, Aleksandra; Bojić, Tijana

    2015-03-01

    Organization of resting state cortical networks is of fundamental importance for the phenomenon of awareness, which is altered in the first part of hypnagogic period (Hori stages 1-4). Our aim was to investigate the change in brain topography pattern of EEG alpha attractor correlation dimension (CD) in the period of transition from Hori stage 1 to 4. EEG of ten healthy adult individuals was recorded in the wake and drowsy states, using a 14 channel average reference montage, from which 91 bipolar channels were derived and filtered in the wider alpha (6-14 Hz) range. Sixty 1s long epochs of each state and individual were subjected to CD calculation according to the Grassberger-Procaccia method. For such a collection of signals, two embedding dimensions, d={5, 10}, and 22 time delays τ=2-23 samples were explored. Optimal values were d=10 and τ=18, where both saturation and second zero crossing of the autocorrelation function occurred. Bipolar channel CD underwent a significant decrease during the transition and showed a positive linear correlation with electrode distance, stronger in the wake individuals. Topographic distribution of bipolar channels with above median CD changed from longitudinal anterior-posterior pattern (awake) to a more diagonal pattern, with localization in posterior regions (drowsiness). Our data are in line with the literature reporting functional segregation of neuronal assemblies in anterior and posterior regions during this transition. Our results should contribute to understanding of complex reorganization of the cortical part of alpha generators during the wake/drowsy transition. PMID:25462218

  13. Long-Range Temporal Correlations in the amplitude of alpha oscillations predict and reflect strength of intracortical facilitation: Combined TMS and EEG study.

    PubMed

    Fedele, Tommaso; Blagovechtchenski, Evgeny; Nazarova, Maria; Iscan, Zafer; Moiseeva, Victoria; Nikulin, Vadim V

    2016-09-01

    While variability of the motor responses to transcranial magnetic stimulation (TMS) is widely acknowledged, little is known about its central origin. One plausible explanation for such variability may relate to different neuronal states defining the reactivity of the cortex to TMS. In this study intrinsic spatio-temporal neuronal dynamics were estimated with Long-Range Temporal Correlations (LRTC) in order to predict the inter-individual differences in the strength of intra-cortical facilitation (ICF) and short-interval intracortical inhibition (SICI) produced by paired-pulse TMS (ppTMS) of the left primary motor cortex. LRTC in the alpha frequency range were assessed from multichannel electroencephalography (EEG) obtained at rest before and after the application of and single-pulse TMS (spTMS) and ppTMS protocols. For the EEG session, preceding TMS application, we showed a positive correlation across subjects between the strength of ICF and LRTC in the fronto-central and parietal areas. This in turn attests to the existence of subject-specific neuronal phenotypes defining the reactivity of the brain to ppTMS. In addition, we also showed that ICF was associated with the changes in neuronal dynamics in the EEG session after the application of the stimulation. This result provides a complementary evidence for the recent findings demonstrating that the cortical stimulation with sparse non-regular stimuli might have considerable long-lasting effects on the cortical activity. PMID:27318302

  14. Effects of Physical Exercise on Individual Resting State EEG Alpha Peak Frequency

    PubMed Central

    Gutmann, Boris; Mierau, Andreas; Hülsdünker, Thorben; Przyklenk, Axel; Strüder, Heiko Klaus

    2015-01-01

    Previous research has shown that both acute and chronic physical exercises can induce positive effects on brain function and this is associated with improvements in cognitive performance. However, the neurophysiological mechanisms underlying the beneficial effects of exercise on cognitive processing are not well understood. This study examined the effects of an acute bout of physical exercise as well as four weeks of exercise training on the individual resting state electroencephalographic (EEG) alpha peak frequency (iAPF), a neurophysiological marker of the individual's state of arousal and attention, in healthy young adults. The subjects completed a steady state exercise (SSE) protocol or an exhaustive exercise (EE) protocol, respectively, on two separate days. EEG activity was recorded for 2 min before exercise, immediately after exercise, and after 10 min of rest. All assessments were repeated following four weeks of exercise training to investigate whether an improvement in physical fitness modulates the resting state iAPF and/or the iAPF response to an acute bout of SSE and EE. The iAPF was significantly increased following EE (P = 0.012) but not following SSE. It is concluded that the iAPF is increased following intense exercise, indicating a higher level of arousal and preparedness for external input. PMID:25759762

  15. Modulation of Alpha Oscillations in the Human EEG with Facial Preference

    PubMed Central

    Kang, Jae-Hwan; Kim, Su Jin; Cho, Yang Seok; Kim, Sung-Phil

    2015-01-01

    Facial preference that results from the processing of facial information plays an important role in social interactions as well as the selection of a mate, friend, candidate, or favorite actor. However, it still remains elusive which brain regions are implicated in the neural mechanisms underlying facial preference, and how neural activities in these regions are modulated during the formation of facial preference. In the present study, we investigated the modulation of electroencephalography (EEG) oscillatory power with facial preference. For the reliable assessments of facial preference, we designed a series of passive viewing and active choice tasks. In the former task, twenty-four face stimuli were passively viewed by participants for multiple times in random order. In the latter task, the same stimuli were then evaluated by participants for their facial preference judgments. In both tasks, significant differences between the preferred and non-preferred faces groups were found in alpha band power (8–13 Hz) but not in other frequency bands. The preferred faces generated more decreases in alpha power. During the passive viewing task, significant differences in alpha power between the preferred and non-preferred face groups were observed at the left frontal regions in the early (0.15–0.4 s) period during the 1-s presentation. By contrast, during the active choice task when participants consecutively watched the first and second face for 1 s and then selected the preferred one, an alpha power difference was found for the late (0.65–0.8 s) period over the whole brain during the first face presentation and over the posterior regions during the second face presentation. These results demonstrate that the modulation of alpha activity by facial preference is a top-down process, which requires additional cognitive resources to facilitate information processing of the preferred faces that capture more visual attention than the non-preferred faces. PMID:26394328

  16. Modulation of Alpha Oscillations in the Human EEG with Facial Preference.

    PubMed

    Kang, Jae-Hwan; Kim, Su Jin; Cho, Yang Seok; Kim, Sung-Phil

    2015-01-01

    Facial preference that results from the processing of facial information plays an important role in social interactions as well as the selection of a mate, friend, candidate, or favorite actor. However, it still remains elusive which brain regions are implicated in the neural mechanisms underlying facial preference, and how neural activities in these regions are modulated during the formation of facial preference. In the present study, we investigated the modulation of electroencephalography (EEG) oscillatory power with facial preference. For the reliable assessments of facial preference, we designed a series of passive viewing and active choice tasks. In the former task, twenty-four face stimuli were passively viewed by participants for multiple times in random order. In the latter task, the same stimuli were then evaluated by participants for their facial preference judgments. In both tasks, significant differences between the preferred and non-preferred faces groups were found in alpha band power (8-13 Hz) but not in other frequency bands. The preferred faces generated more decreases in alpha power. During the passive viewing task, significant differences in alpha power between the preferred and non-preferred face groups were observed at the left frontal regions in the early (0.15-0.4 s) period during the 1-s presentation. By contrast, during the active choice task when participants consecutively watched the first and second face for 1 s and then selected the preferred one, an alpha power difference was found for the late (0.65-0.8 s) period over the whole brain during the first face presentation and over the posterior regions during the second face presentation. These results demonstrate that the modulation of alpha activity by facial preference is a top-down process, which requires additional cognitive resources to facilitate information processing of the preferred faces that capture more visual attention than the non-preferred faces. PMID:26394328

  17. Childhood EEG frontal alpha power as a predictor of adolescent antisocial behavior: A twin heritability study

    PubMed Central

    Niv, Sharon; Ashrafulla, Syed; Tuvblad, Catherine; Joshi, Anand; Raine, Adrian; Leahy, Richard; Baker, Laura A.

    2015-01-01

    High EEG frontal alpha power (FAP) is thought to represent a state of low arousal in the brain, which has been related in past research to antisocial behavior (ASB). We investigated a longitudinal sample of 900 twins in two assessments in late childhood and mid-adolescence to verify whether relationships exist between FAP and both aggressive and nonaggressive ASB. ASB was measured by the Child Behavioral Checklist, and FAP was calculated using connectivity analysis methods that used principal components analysis to derive power of the most dominant frontal activation. Significant positive predictive relationships emerged in males between childhood FAP and adolescent aggressive ASB using multilevel mixed modeling. No concurrent relationships were found. Using bivariate biometric twin modeling analysis, the relationship between childhood FAP and adolescent aggressive ASB in males was found to be entirely due to genetic factors, which were correlated r = 0.22. PMID:25456277

  18. Childhood EEG frontal alpha power as a predictor of adolescent antisocial behavior: a twin heritability study.

    PubMed

    Niv, Sharon; Ashrafulla, Syed; Tuvblad, Catherine; Joshi, Anand; Raine, Adrian; Leahy, Richard; Baker, Laura A

    2015-02-01

    High EEG frontal alpha power (FAP) is thought to represent a state of low arousal in the brain, which has been related in past research to antisocial behavior (ASB). We investigated a longitudinal sample of 900 twins in two assessments in late childhood and mid-adolescence to verify whether relationships exist between FAP and both aggressive and nonaggressive ASB. ASB was measured by the Child Behavioral Checklist, and FAP was calculated using connectivity analysis methods that used principal components analysis to derive power of the most dominant frontal activation. Significant positive predictive relationships emerged in males between childhood FAP and adolescent aggressive ASB using multilevel mixed modeling. No concurrent relationships were found. Using bivariate biometric twin modeling analysis, the relationship between childhood FAP and adolescent aggressive ASB in males was found to be entirely due to genetic factors, which were correlated r=0.22. PMID:25456277

  19. EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study.

    PubMed

    Sonnleitner, Andreas; Treder, Matthias Sebastian; Simon, Michael; Willmann, Sven; Ewald, Arne; Buchner, Axel; Schrauf, Michael

    2014-01-01

    Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers' mental states during a primary driving task. N=20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers' mental states. Results show that reaction times and alpha spindle rate increased with time-on-task. Moreover, brake reaction times and alpha spindle rate were significantly higher while driving with auditory secondary task opposed to driving only. In single-trial classification, a combination of spindle parameters yielded a median classification error of about 8% in discriminating the distracted from the alert driving. Reduced driving performance (i.e., prolonged brake reaction times) during increased cognitive load is assumed to be indicated by EEG alpha spindles, enabling the quantification of driver distraction in experiments on public roads without verbally assessing the drivers' mental states. PMID:24144496

  20. Effects of Instructions and Biofeedback on EEG-Alpha Production and the Effects of EEG-Alpha Biofeedback Training for Controlling Arousal in a Subsequent Stressful Situation.

    ERIC Educational Resources Information Center

    Holmes, David S.; And Others

    1980-01-01

    Results indicate that the instructions (and related information concerning alpha) rather than the biofeedback are critical in alpha biofeedback training and that this training does not appear to have utility for controlling arousal under stress. (Author)

  1. EEG upper/low alpha frequency power ratio relates to temporo-parietal brain atrophy and memory performances in mild cognitive impairment

    PubMed Central

    Moretti, Davide V.; Paternicò, Donata; Binetti, Giuliano; Zanetti, Orazio; Frisoni, Giovanni B.

    2013-01-01

    Objective: Temporo-parietal cortex thinning is associated to mild cognitive impairment (MCI) due to Alzheimer disease (AD). The increase of EEG upper/low alpha power ratio has been associated with AD-converter MCI subjects. We investigated the association of alpha3/alpha2 ratio with patterns of cortical thickness in MCI. Materials and Methods: Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording and high resolution 3D magnetic resonance imaging. Alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. Three MCI groups were detected according to increasing tertile values of upper/low alpha power ratio. Difference of cortical thickness among the groups was estimated. Pearson’s r was used to assess the topography of the correlation between cortical thinning and memory impairment. Results: High upper/low alpha power ratio group had total cortical gray matter volume reduction of 471 mm2 than low upper/low alpha power ratio group (p < 0.001). Upper/low alpha group showed a similar but less marked pattern (160 mm2) of cortical thinning when compared to middle upper/low alpha power ratio group (p < 0.001). Moreover, high upper/low alpha group had wider cortical thinning than other groups, mapped to the Supramarginal and Precuneus bilaterally. Finally, in high upper/low alpha group temporo-parietal cortical thickness was correlated to memory performance. No significant cortical thickness differences was found between middle and low alpha3/alpha2 power ratio groups. Conclusion: High EEG upper/low alpha power ratio was associated with temporo-parietal cortical thinning and memory impairment in MCI subjects. The combination of EEG upper/low alpha ratio and cortical thickness measure could be useful for identifying individuals at risk for progression to AD dementia and may be of value in clinical context. PMID:24187540

  2. Effects of Drawing on Alpha Activity: A Quantitative EEG Study with Implications for Art Therapy

    ERIC Educational Resources Information Center

    Belkofer, Christopher M.; Van Hecke, Amy Vaughan; Konopka, Lukasz M.

    2014-01-01

    Little empirical evidence exists as to how materials used in art therapy affect the brain and its neurobiological functioning. This pre/post within-groups study utilized the quantitative electroencephalogram (qEEG) to measure residual effects in the brain after 20 minutes of drawing. EEG recordings were conducted before and after participants (N =…

  3. EEG alpha desynchronization in musicians and nonmusicians in response to changes in melody, tempo, and key in classical music.

    PubMed

    Overman, Amy A; Hoge, Jessica; Dale, J Alexander; Cross, Jeffrey D; Chien, Alec

    2003-10-01

    Two experiments were performed to examine musicians' and nonmusicians' electroencephalographic (EEG) responses to changes in major dimensions (tempo, melody, and key) of classical music. In Exp. 1, 12 nonmusicians' and 12 musicians' EEGs during melody and tempo changes in classical music showed more alpha desynchronization in the left hemisphere (F3) for changes in tempo than in the right. For melody, the nonmusicians were more right-sided (F4) than left in activation, and musicians showed no left-right differences. In Exp. 2, 18 musicians' and 18 nonmusicians' EEG after a key change in classical music showed that distant key changes elicited more right frontal (F4) alpha desynchronization than left. Musicians showed more reaction to key changes than nonmusicians and instructions to attend to key changes had no significant effect. Classical music, given its well-defined structure, offers a unique set of stimuli to study the brain. Results support the concept of hierarchical modularity in music processing that may be automatic. PMID:14620240

  4. Genetic and Environmental Influences on Frontal EEG Asymmetry and Alpha Power in 9–10 Year Old Twins

    PubMed Central

    Gao, Yu; Tuvblad, Catherine; Raine, Adrian; Lozano, Dora I.; Baker, Laura A.

    2008-01-01

    Modest genetic influences on frontal EEG asymmetry have been found in adults, but little is known about its genetic origins in children. Resting frontal asymmetry and alpha power were examined in 951 9–10-year-old twins. Results showed that in both males and females: (1) a modest but significant amount of variance in frontal asymmetry was accounted for by genetic factors (11–27%) with the remainder accounted for by non-shared environmental influences, and (2) alpha power were highly heritable, with 70–85% of the variance accounted for by genetic factors. Results suggest that the genetic architecture of frontal asymmetry and alpha power in late childhood are similar to that in adulthood and that the high non-shared environmental influences on frontal asymmetry may reflect environmentally-influenced individual differences in the maturation of frontal cortex as well as state-dependent influences on specific measurements. PMID:19386046

  5. Audio-Visual and Autogenic Relaxation Alter Amplitude of Alpha EEG Band, Causing Improvements in Mental Work Performance in Athletes.

    PubMed

    Mikicin, Mirosław; Kowalczyk, Marek

    2015-09-01

    The aim of the present study was to investigate the effect of regular audio-visual relaxation combined with Schultz's autogenic training on: (1) the results of behavioral tests that evaluate work performance during burdensome cognitive tasks (Kraepelin test), (2) changes in classical EEG alpha frequency band, neocortex (frontal, temporal, occipital, parietal), hemisphere (left, right) versus condition (only relaxation 7-12 Hz). Both experimental (EG) and age-and skill-matched control group (CG) consisted of eighteen athletes (ten males and eight females). After 7-month training EG demonstrated changes in the amplitude of mean electrical activity of the EEG alpha bend at rest and an improvement was significantly changing and an improvement in almost all components of Kraepelin test. The same examined variables in CG were unchanged following the period without the intervention. Summing up, combining audio-visual relaxation with autogenic training significantly improves athlete's ability to perform a prolonged mental effort. These changes are accompanied by greater amplitude of waves in alpha band in the state of relax. The results suggest usefulness of relaxation techniques during performance of mentally difficult sports tasks (sports based on speed and stamina, sports games, combat sports) and during relax of athletes. PMID:26016588

  6. Positive Emotional Experience: Induced by Vibroacoustic Stimulation Using a Body Monochord in Patients with Psychosomatic Disorders: Is Associated with an Increase in EEG-Theta and a Decrease in EEG-Alpha Power.

    PubMed

    Sandler, H; Tamm, S; Fendel, U; Rose, M; Klapp, B F; Bösel, R

    2016-07-01

    Relaxation and meditation techniques are generally characterized by focusing attention, which is associated with an increase of frontal EEG Theta. Some studies on music perception suggest an activation of Frontal Midline Theta during emotionally positive attribution, others display a lateralization of electrocortical processes in the attribution of music induced emotion of different valence. The present study examined the effects of vibroacoustic stimulation using a Body Monochord and the conventional relaxation music from an audio CD on the spontaneous EEG of patients suffering from psychosomatic disorders (N = 60). Each treatment took about 20 min and was presented to the patients in random order. Subjective experience was recorded via self-rating scale. EEG power spectra of the Theta, Alpha-1 and Alpha-2 bands were analysed and compard between the two treatment conditions. There was no lateralization of electrocortical activity in terms of the emotional experience of the musical pieces. A reduction in Alpha-2 power occurred during both treatments. An emotionally positive attribution of the experience of the vibroacoustically induced relaxation state is characterized by a more pronounced release of control. In the context of focused attention this is interpreted as flow experience. The spontaneous EEG showed an increase in Theta power, particularly in the frontal medial and central medial area, and a greater reduction in Alpha-2 power. The intensity of positive emotional feelings during the CD music showed no significant effect on the increase in Theta power. PMID:26936595

  7. Alpha 1-antitrypsin levels and phenotypes and hepatitis B serology in liver cancer.

    PubMed Central

    Sparos, L.; Tountas, Y.; Chapuis-Cellier, C.; Theodoropoulos, G.; Trichopoulos, D.

    1984-01-01

    Serum levels of alpha 1-antitrypsin (alpha 1 AT) were measured by radial immunodiffusion and phenotypes were determined by electrofocusing in acrylamide gel in 39 patients with hepatocellular carcinoma (HCC) positive for serum hepatitis B surface antigen (HBsAg), 41 patients with HCC negative for serum HBsAg, and 160 age- and sex-matched hospital controls. There was no difference between the control series and either of the two HCC groups with respect to alpha 1 AT phenotype pattern; also, there was no evidence of association between HCC and either the M2 allele or any of the alpha 1 AT deficiency phenotypes. However, HCC cases negative for HBsAg had significantly higher serum alpha 1 AT values (mean 665 +/- 26 mg 100 ml-1) than HCC cases positive for HBsAg (mean 571 +/- 23 mg 100 ml-1), who in turn, had significantly higher alpha 1 AT values than hospital controls (mean 434 +/- 13 mg 100 ml-1). These results indicate that in Greece, as in other high HCC incidence countries, genetically determined alpha 1 AT deficiency is not aetiologically important; the increase of serum alpha 1 AT is an important correlate of HCC with possible aetiologic significance and diagnostic potential and HBsAg-positive HCC and HBsAg-negative HCC are manifest differently as well as being aetiologically distinct. PMID:6326791

  8. Brain-training for physical performance: a study of EEG-neurofeedback and alpha relaxation training in athletes.

    PubMed

    Mikicin, Mirosław; Orzechowski, Grzegorz; Jurewicz, Katarzyna; Paluch, Katarzyna; Kowalczyk, Marek; Wróbel, Andrzej

    2015-01-01

    In recent years, EEG-neurofeedback training (EEG-NFB) has been increasingly used to optimize various brain functions. Better performance in various activities was also reported after relaxation trainings, another popular method in therapeutic practice. Both these methods are used as a part of professional coaching in sports training centers. In the present study, we aimed to evaluate the impact of such holistic training on physiological (EEG) and behavioral measures on semi-professional athletes. EEG-NFB paradigm was intended for amplification of the amplitudes of SMR (12-15 Hz) and beta1 (13-20 Hz) bands and simultaneous reduction of the amplitude of theta (4-7.5 Hz) and beta2 (20-30 Hz). Participation in NFB sessions was accompanied with self-administration of relaxing, audio-visual stimulation after each daily athletic training session. The training program resulted in the increase of alpha and beta1 power of trained participants when assessed in rest with eyes-closed. In eyes - open state, participants of the trained group maintained the same level in all frequency bands, in opposite to the control subjects, whose power decreased in the second measurement in beta1 band when compared to the first one. The trained group exhibited greater reduction of reaction times in a test of visual attention than the control group and showed improvement in several performance measures of Kraepelin's work-curve, used to evaluate speed, effectiveness and work accuracy. Together, these results present initial support for the use of holistic, neurophysiological training in sports workout. PMID:26994421

  9. Placebo Analgesia Changes Alpha Oscillations Induced by Tonic Muscle Pain: EEG Frequency Analysis Including Data during Pain Evaluation

    PubMed Central

    Li, Linling; Wang, Hui; Ke, Xijie; Liu, Xiaowu; Yuan, Yuan; Zhang, Deren; Xiong, Donglin; Qiu, Yunhai

    2016-01-01

    Placebo exhibits beneficial effects on pain perception in human experimental studies. Most of these studies demonstrate that placebo significantly decreased neural activities in pain modulatory brain regions and pain-evoked potentials. This study examined placebo analgesia-related effects on spontaneous brain oscillations. We examined placebo effects on four order-fixed 20-min conditions in two sessions: isotonic saline-induced control conditions (with/without placebo) followed by hypertonic saline-induced tonic muscle pain conditions (with/without placebo) in 19 subjects using continuous electroencephalography (EEG) recording. Placebo treatment exerted significant analgesic effects in 14 placebo responders, as subjective intensity of pain perception decreased. Frequency analyses were performed on whole continuous EEG data, data during pain perception rating and data after rating. The results in the first two cases revealed that placebo induced significant increases and a trend toward significant increases in the amplitude of alpha oscillation during tonic muscle pain compared to control conditions in frontal-central regions of the brain, respectively. Placebo-induced decreases in the subjective intensity of pain perception significantly and positively correlated with the increases in the amplitude of alpha oscillations during pain conditions. In conclusion, the modulation effect of placebo treatment was captured when the pain perception evaluating period was included. The strong correlation between the placebo effect on reported pain perception and alpha amplitude suggest that alpha oscillations in frontal-central regions serve as a cortical oscillatory basis of the placebo effect on tonic muscle pain. These results provide important evidence for the investigation of objective indicators of the placebo effect. PMID:27242501

  10. Sensitivity of Alpha and Beta Oscillations to Sensorimotor Characteristics of Action: An EEG Study of Action Production and Gesture Observation

    PubMed Central

    Quandt, Lorna C.; Marshall, Peter J.; Shipley, Thomas F.; Beilock, Sian L.; Goldin-Meadow, Susan

    2012-01-01

    The sensorimotor experiences we gain when performing an action have been found to influence how our own motor systems are activated when we observe others performing that same action. Here we asked whether this phenomenon applies to the observation of gesture. Would the sensorimotor experiences we gain when performing an action on an object influence activation in our own motor systems when we observe others performing a gesture for that object? Participants were given sensorimotor experience with objects that varied in weight, and then observed video clips of an actor producing gestures for those objects. Electroencephalography (EEG) was recorded while participants first observed either an iconic gesture (pantomiming lifting an object) or a deictic gesture (pointing to an object) for an object, and then grasped and lifted the object indicated by the gesture. We analyzed EEG during gesture observation to determine whether oscillatory activity was affected by the observer’s sensorimotor experiences with the object represented in the gesture. Seeing a gesture for an object previously experienced as light was associated with a suppression of power in alpha and beta frequency bands, particularly at posterior electrodes. A similar pattern was found when participants lifted the light object, but over more diffuse electrodes. Moreover, alpha and beta bands at right parieto-occipital electrodes were sensitive to the type of gesture observed (iconic vs. deictic). These results demonstrate that sensorimotor experience with an object affects how a gesture for that object is processed, as measured by the gesture-observer’s EEG, and suggest that different types of gestures recruit the observer’s own motor system in different ways. PMID:22910276

  11. Neurofeedback training of EEG alpha rhythm enhances episodic and working memory.

    PubMed

    Hsueh, Jen-Jui; Chen, Tzu-Shan; Chen, Jia-Jin; Shaw, Fu-Zen

    2016-07-01

    Neurofeedback training (NFT) of the alpha rhythm has been used for several decades but is still controversial in regards to its trainability and effects on working memory. Alpha rhythm of the frontoparietal region are associated with either the intelligence or memory of healthy subjects and are also related to pathological states. In this study, alpha NFT effects on memory performances were explored. Fifty healthy participants were recruited and randomly assigned into a group receiving a 8-12-Hz amplitude (Alpha) or a group receiving a random 4-Hz amplitude from the range of 7 to 20 Hz (Ctrl). Three NFT sessions per week were conducted for 4 weeks. Working memory was assessed by both a backward digit span task and an operation span task, and episodic memory was assessed using a word pair task. Four questionnaires were used to assess anxiety, depression, insomnia, and cognitive function. The Ctrl group had no change in alpha amplitude and duration. In contrast, the Alpha group showed a progressive significant increase in the alpha amplitude and total alpha duration of the frontoparietal region. Accuracies of both working and episodic memories were significantly improved in a large proportion of participants of the Alpha group, particularly for those with remarkable alpha-amplitude increases. Scores of four questionnaires fell in a normal range before and after NFT. The current study provided supporting evidence for alpha trainability within a small session number compared with that of therapy. The findings suggested the enhancement of working and episodic memory through alpha NFT. Hum Brain Mapp 37:2662-2675, 2016. © 2016 Wiley Periodicals, Inc. PMID:27038114

  12. Aperiodic phase re-setting in scalp EEG of beta-gamma oscillations by state transitions at alpha-theta rates.

    PubMed

    Freeman, Walter J; Burke, Brian C; Holmes, Mark D

    2003-08-01

    We evaluated the rapid changes in regional scalp EEG synchronization in normal subjects with spatial and temporal resolution exceeding prior art 10-fold with a high spatial density array and the Hilbert transform. A curvilinear array of 64 electrodes 3 mm apart extending 18.9 cm across the scalp was used to record EEG at 200/sec. Analytic amplitude (AA) and phase (AP) were calculated at each time step for the 64 traces in the analog pass band of 0.5-120 Hz. AP differences approximated the AP derivative (instantaneous frequency). The AP from unfiltered EEG revealed no reproducible patterns. Filtering was necessary in the beta and gamma ranges according to a technique that optimized the correlation of the AP differences with the activity band pass filtered in the alpha range. The sizes of temporal AP differences were usually within +/-0.5 radian from the average step corresponding to the center frequency of the pass band. Large AP differences were often synchronized over distances of 6 to 19 cm. An optimal pass band to detect and measure these recurring jumps in AP in the beta and gamma ranges was found by maximizing the alpha peak in the cospectrum of the correlation between unfiltered EEG and the band pass AP differences. Synchronized AP jumps recurred in clusters (CAP) at alpha and theta rates in resting subjects and with EMG. Cortex functions by serial changes in state. The Hilbert transform of EEG from high-density arrays can visualize these state transitions with high temporal and spatial resolution and should be useful in relating EEG to cognition. PMID:12874778

  13. Alpha desynchronization and fronto-parietal connectivity during spatial working memory encoding deficits in ADHD: A simultaneous EEG-fMRI study.

    PubMed

    Lenartowicz, Agatha; Lu, Steven; Rodriguez, Cameron; Lau, Edward P; Walshaw, Patricia D; McCracken, James T; Cohen, Mark S; Loo, Sandra K

    2016-01-01

    The underlying mechanisms of alpha band (8-12 Hz) neural oscillations are of importance to the functioning of attention control systems as well as to neuropsychiatric conditions that are characterized by deficits of that system, such as attention deficit hyperactivity disorder (ADHD). The objectives of the present study were to test if visual encoding-related alpha event-related desynchronization (ERD) correlates with fronto-parieto-occipital connectivity, and whether this is disrupted in ADHD during spatial working memory (SWM) performance. We acquired EEG concurrently with fMRI in thirty boys (12-16 yrs. old, 15 with ADHD), during SWM encoding. Psychophysiological connectivity analyses indicated that alpha ERD during SWM encoding was associated with both occipital activation and fronto-parieto-occipital functional connectivity, a finding that expands on prior associations between alpha ERD and occipital activation. This finding provides novel support for the interpretation of alpha ERD (and the associated changes in occipital activation) as a phenomenon that involves, and perhaps arises as a result of, top-down network interactions. Alpha ERD was associated less strongly with occipital activity, but associated more strongly with fronto-parieto-occipital connectivity in ADHD, consistent with a compensatory attentional response. Additionally, we illustrate that degradation of EEG data quality by MRI-amplified motion artifacts is robust to existing cleaning algorithms and is significantly correlated with hyperactivity symptoms and the ADHD Combined Type diagnosis. We conclude that persistent motion-related MR artifacts in EEG data can increase variance and introduce bias in interpretation of group differences in populations characterized by hypermobility--a clear limitation of current-state EEG-fMRI methodology. PMID:26955516

  14. Cortical EEG alpha rhythms reflect task-specific somatosensory and motor interactions in humans.

    PubMed

    Babiloni, Claudio; Del Percio, Claudio; Arendt-Nielsen, Lars; Soricelli, Andrea; Romani, Gian Luca; Rossini, Paolo Maria; Capotosto, Paolo

    2014-10-01

    Anticipating sensorimotor events allows adaptive reactions to environment with crucial implications for self-protection and survival. Here we review several studies of our group that aimed to test the hypothesis that the cortical processes preparing the elaboration of sensorimotor interaction is reflected by the reduction of anticipatory electroencephalographic alpha power (about 8-12Hz; event-related desynchronization, ERD), as an index that regulate task-specific sensorimotor processes, accounted by high-alpha sub-band (10-12Hz), rather than a general tonic alertness, accounted by low-alpha sub-band (8-10Hz). In this line, we propose a model for human cortical processes anticipating warned sensorimotor interactions. Overall, we reported a stronger high-alpha ERD before painful than non-painful somatosensory stimuli that is also predictive of the subjective evaluation of pain intensity. Furthermore, we showed that anticipatory high-alpha ERD increased before sensorimotor interactions between non-painful or painful stimuli and motor demands involving opposite hands. In contrast, sensorimotor interactions between painful somatosensory and sensorimotor demands involving the same hand decreased anticipatory high-alpha ERD, due to a sort of sensorimotor "gating" effect. In conclusion, we suggest that anticipatory cortical high-alpha rhythms reflect the central interference and/or integration of ascending (sensory) and descending (motor) signals relative to one or two hands before non-painful and painful sensorimotor interactions. PMID:24929901

  15. Phenotypic classification of male pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency

    SciTech Connect

    Sinnecker, G.H.G; Hiort, O.; Kruse, K.; Dibbelt, L.

    1996-05-03

    Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5{alpha}-reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virilization without gynecomastia at puberty. We investigated nine patients with steroid 5{alpha}-reductase 2 deficiency (SRD). T/DHT-ratios were highly increased in the classical syndrome, but variable in the less severe affected patients. Mutations in the SRD5A2 gene had been characterized using PCR-SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5{alpha}-reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency. 22 refs., 2 figs., 2 tabs.

  16. Effects of Heart Rate Variability Biofeedback on EEG Alpha Asymmetry and Anxiety Symptoms in Male Athletes: A Pilot Study.

    PubMed

    Dziembowska, Inga; Izdebski, Paweł; Rasmus, Anna; Brudny, Janina; Grzelczak, Marta; Cysewski, Piotr

    2016-06-01

    Heart rate variability biofeedback (HRV-BFB) has been shown as useful tool to manage stress in various populations. The present study was designed to investigate whether the biofeedback-based stress management tool consisting of rhythmic breathing, actively self-generated positive emotions and a portable biofeedback device induce changes in athletes' HRV, EEG patterns, and self-reported anxiety and self-esteem. The study involved 41 healthy male athletes, aged 16-21 (mean 18.34 ± 1.36) years. Participants were randomly divided into two groups: biofeedback and control. Athletes in the biofeedback group received HRV biofeedback training, athletes in the control group didn't receive any intervention. During the randomized controlled trial (days 0-21), the mean anxiety score declined significantly for the intervention group (change-4 p < 0.001) but not for the control group (p = 0.817). In addition, as compared to the control, athletes in biofeedback group showed substantial and statistically significant improvement in heart rate variability indices and changes in power spectra of both theta and alpha brain waves, and alpha asymmetry. These changes suggest better self-control in the central nervous system and better flexibility of the autonomic nervous system in the group that received biofeedback training. A HRV biofeedback-based stress management tool may be beneficial for stress reduction for young male athletes. PMID:26459346

  17. Brief Report: Reduced Temporal-Central EEG Alpha Coherence during Joint Attention Perception in Adolescents with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Jaime, Mark; McMahon, Camilla M.; Davidson, Bridget C.; Newell, Lisa C.; Mundy, Peter C.; Henderson, Heather A.

    2016-01-01

    Although prior studies have demonstrated reduced resting state EEG coherence in adults with autism spectrum disorder (ASD), no studies have explored the nature of EEG coherence during joint attention. We examined the EEG coherence of the joint attention network in adolescents with and without ASD during congruent and incongruent joint attention…

  18. Pulsed Out of Awareness: EEG Alpha Oscillations Represent a Pulsed-Inhibition of Ongoing Cortical Processing

    PubMed Central

    Mathewson, Kyle E.; Lleras, Alejandro; Beck, Diane M.; Fabiani, Monica; Ro, Tony; Gratton, Gabriele

    2011-01-01

    Alpha oscillations are ubiquitous in the brain, but their role in cortical processing remains a matter of debate. Recently, evidence has begun to accumulate in support of a role for alpha oscillations in attention selection and control. Here we first review evidence that 8–12 Hz oscillations in the brain have a general inhibitory role in cognitive processing, with an emphasis on their role in visual processing. Then, we summarize the evidence in support of our recent proposal that alpha represents a pulsed-inhibition of ongoing neural activity. The phase of the ongoing electroencephalography can influence evoked activity and subsequent processing, and we propose that alpha exerts its inhibitory role through alternating microstates of inhibition and excitation. Finally, we discuss evidence that this pulsed-inhibition can be entrained to rhythmic stimuli in the environment, such that preferential processing occurs for stimuli at predictable moments. The entrainment of preferential phase may provide a mechanism for temporal attention in the brain. This pulsed inhibitory account of alpha has important implications for many common cognitive phenomena, such as the attentional blink, and seems to indicate that our visual experience may at least some times be coming through in waves. PMID:21779257

  19. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading.

    PubMed

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading. PMID:26076026

  20. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading

    PubMed Central

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading. PMID:26076026

  1. Spontaneous EEG alpha oscillation interacts with positive and negative BOLD responses in the visual-auditory cortices and default-mode network.

    PubMed

    Mayhew, Stephen D; Ostwald, Dirk; Porcaro, Camillo; Bagshaw, Andrew P

    2013-08-01

    The human brain is continually, dynamically active and spontaneous fluctuations in this activity play a functional role in affecting both behavioural and neuronal responses. However, the mechanisms through which this occurs remain poorly understood. Simultaneous EEG-fMRI is a promising technique to study how spontaneous activity modulates the brain's response to stimulation, as temporal indices of ongoing cortical excitability can be integrated with spatially localised evoked responses. Here we demonstrate an interaction between the ongoing power of the electrophysiological alpha oscillation and the magnitude of both positive (PBR) and negative (NBR) fMRI responses to two contrasts of visual checkerboard reversal. Furthermore, the amplitude of pre-stimulus EEG alpha-power significantly modulated the amplitude and shape of subsequent PBR and NBR to the visual stimulus. A nonlinear reduction of visual PBR and an enhancement of auditory NBR and default-mode network NBR were observed in trials preceded by high alpha-power. These modulated areas formed a functionally connected network during a separate resting-state recording. Our findings suggest that the "baseline" state of the brain exhibits considerable trial-to-trial variability which arises from fluctuations in the balance of cortical inhibition/excitation that are represented by respective increases/decreases in the power of the EEG alpha oscillation. The consequence of this spontaneous electrophysiological variability is modulated amplitudes of both PBR and NBR to stimulation. Fluctuations in alpha-power may subserve a functional relationship in the visual-auditory network, acting as mediator for both short and long-range cortical inhibition, the strength of which is represented in part by NBR. PMID:23507378

  2. Alpha interferon in T helper phenotype chronic lymphocytic leukemia: a report of three cases.

    PubMed

    Cuneo, A; Lanza, F; Spanedda, R; Tomasi, P; Ferrari, L; Castoldi, G L

    1988-01-01

    Three patients affected by T helper chronic lymphocytic leukemia were treated with low dose interferon alpha-2b (3 MU/m2 3 times weekly). The disease presented different pathologic expressions with diffuse skin lesions in one patient, a mild clinical course and a prolymphocytic variant with aggressive features, respectively, in the other two cases. A consistent response was observed within 3-6 weeks; by that time a reduction of blood and marrow lymphocytosis in the three patients and a regression of the cutaneous lesions were documented. Therefore, it should be emphasized that the use of alpha IFN, whose effectiveness on cutaneous T cell lymphomas has been already demonstrated, may represent an active agent in the treatment of leukemic T helper phenotype chronic lymphocytic proliferations. PMID:2972175

  3. Atrophy and lower regional perfusion of temporo-parietal brain areas are correlated with impairment in memory performances and increase of EEG upper alpha power in prodromal Alzheimer’s disease

    PubMed Central

    Moretti, Vito Davide

    2015-01-01

    Background: Temporo-parietal cortex thinning is associated with mild cognitive impairment (MCI) due to Alzheimer’s disease (AD). The increase of the EEG upper/low alpha power ratio has been associated with MCI due to AD subjects and to the atrophy of temporo-parietal brain areas. Moreover, subjects with a higher alpha3/alpha2 frequency power ratio showed lower brain perfusion than in the low alpha3/alpha2 group. The two groups have significantly different hippocampal volumes and correlation with the theta frequency activity. Methods: 74 adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording, and high resolution 3D magnetic resonance imaging (MRI). 27 of them underwent EEG recording and perfusion single-photon emission computed tomography (SPECT) evaluation. The alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. The difference in cortical thickness between the groups was estimated. Pearson’s r was used to assess the correlation topography between cortical thinning as well as between brain perfusion and memory impairment. Results: In the higher upper/low alpha group, memory impairment was more pronounced both in the MRI group and the SPECT MCI group. Moreover, it was correlated with greater cortical atrophy and lower perfusional rate in temporo-parietal cortex. Conclusion: High EEG upper/low alpha power ratio was associated with cortical thinning lower perfusion in temporo-parietal. Moreover, atrophy and lower perfusional rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context. PMID:26389016

  4. Gastric Composite Tumor of Alpha Fetoprotein-Producing Carcinoma/Hepatoid Adenocarcinoma and Endocrine Carcinoma with Reference to Cellular Phenotypes

    PubMed Central

    Suzuki, Akira; Koide, Naohiko; Kitazawa, Masato; Mochizuka, Akiyoshi; Ota, Hiroyoshi; Miyagawa, Shinichi

    2012-01-01

    Alpha-fetoprotein-producing carcinoma (AFPC)/hepatoid adenocarcinoma (HAC) and neuroendocrine carcinoma (NEC) are uncommon in the stomach. Composite tumors consisting of these carcinomas and their histologic phenotypes are not well known. Between 2002 and 2007, to estimate the prevalence of composite tumors consisting of tubular adenocarcinoma, AFPC/HAC and NEC, we reviewed specimens obtained from 294 consecutive patients treated surgically for gastric cancer. We examined histological phenotype of tumors of AFPC or NEC containing the composite tumor by evaluating immunohistochemical expressions of MUC2, MUC5AC, MUC6, CDX2, and SOX2. Immunohistochemically, AFPC/HAC dominantly showed the intestinal or mixed phenotype, and NEC frequently showed the gastric phenotype. In the composite tumor, the tubular and hepatoid components showed the gastric phenotype, and the neuroendocrine component showed the mixed type. The unique composite tumor predominantly showed the gastric phenotype, and the hepatoid and neuroendocrine components were considered to be differentiated from the tubular component. PMID:22482081

  5. Resting state glutamate predicts elevated pre-stimulus alpha during self-relatedness: A combined EEG-MRS study on "rest-self overlap".

    PubMed

    Bai, Yu; Nakao, Takashi; Xu, Jiameng; Qin, Pengmin; Chaves, Pedro; Heinzel, Alexander; Duncan, Niall; Lane, Timothy; Yen, Nai-Shing; Tsai, Shang-Yueh; Northoff, Georg

    2016-06-01

    Recent studies have demonstrated neural overlap between resting state activity and self-referential processing. This "rest-self" overlap occurs especially in anterior cortical midline structures like the perigenual anterior cingulate cortex (PACC). However, the exact neurotemporal and biochemical mechanisms remain to be identified. Therefore, we conducted a combined electroencephalography (EEG)-magnetic resonance spectroscopy (MRS) study. EEG focused on pre-stimulus (e.g., prior to stimulus presentation or perception) power changes to assess the degree to which those changes can predict subjects' perception (and judgment) of subsequent stimuli as high or low self-related. MRS measured resting state concentration of glutamate, focusing on PACC. High pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power significantly correlated with both perception of stimuli judged to be highly self-related and with resting state glutamate concentrations in the PACC. In sum, our results show (i) pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power and resting state glutamate concentration to mediate rest-self overlap that (ii) dispose or incline subjects to assign high degrees of self-relatedness to perceptual stimuli. PMID:26207415

  6. Mutation in collagen II alpha 1 isoforms delineates Stickler and Wagner syndrome phenotypes

    PubMed Central

    Tran-Viet, Khanh-Nhat; Soler, Vincent; Quiette, Valencia; Powell, Caldwell; Yanovitch, Tammy; Metlapally, Ravikanth; Luo, Xiaoyan; Katsanis, Nicholas; Nading, Erica

    2013-01-01

    Purpose Stickler syndrome is an arthro-ophthalmopathy with phenotypic overlap with Wagner syndrome. The common Stickler syndrome type I is inherited as an autosomal dominant trait, with causal mutations in collagen type II alpha 1 (COL2A1). Wagner syndrome is associated with mutations in versican (VCAN), which encodes for a chondroitin sulfate proteoglycan. A three-generation Caucasian family variably diagnosed with either syndrome was screened for sequence variants in the COL2A1 and VCAN genes. Methods Genomic DNA samples derived from saliva were collected from all family members (six affected and four unaffected individuals). Complete sequencing of COL2A1 and VCAN was performed on two affected individuals. Direct sequencing of remaining family members was conducted if the discovered variants followed segregation. Results A base-pair substitution (c.258C>A) in exon 2 of COL2A1 cosegregated with familial disease status. This known mutation occurs in a highly conserved site that causes a premature stop codon (p.C86X). The mutation was not seen in 1,142 ethnically matched control DNA samples. Conclusions Premature stop codons in COL2A1 exon 2 lead to a Stickler syndrome type I ocular-only phenotype with few or no systemic manifestations. Mutation screening of COL2A1 exon 2 in families with autosomal dominant vitreoretinopathy is important for accurate clinical diagnosis. PMID:23592912

  7. Alpha1-antitrypsin phenotypes and lung function in a moderately polluted northern Ontario community.

    PubMed Central

    Ostrow, D. N.; Manfreda, J.; Dorman, T.; Cherniack, R. M.

    1978-01-01

    To determine whether persons with intermediate value alpha1-antitrypsin phenotypes living in a polluted environment manifest significant abnormalities in lung function, a study was undertaken of an age-, sex- and smoking-stratified sample of 391 persons from the town of Fort Frances, Ont., which has elevated values of total dustfall, suspended particulates and hydrogen sulfide. Indices of pulmonary function were derived from the maximum expiratory flow and the single breath expiratory flow and the single breath expiratory nitrogen washout curves. The percentage frequency of the M, MS and MZ pheontypes was 91.7, 7.3 and 0.8, respectively. There was no significant difference between the M and MS groups as indicated by the nitrogen washout curve and maximum expiratory flow curve. There was no significant difference between the three MZ subjects and the M group. In both M and MS groups smokers displayed evidence of airflow obstruction when compared with nonsmokers. It would appear that, when compared with M subjects, persons with the MS phenotype living in a moderately polluted area show no changes in indicators of pulmonary function, including tests of early airway disease, that cannot be attributed to their smoking habit. PMID:306869

  8. DETECTION OF NONLINEAR INTERACTIONS OF EEG ALPHA WAVES IN THE BRAIN BY A NEW COHERENCE MEASURE AND ITS APPLICATION TO EPILEPSY AND ANTI-EPILEPTIC DRUG THERAPY

    PubMed Central

    SHERMAN, DAVID; ZHANG, NING; GARG, SHIKHA; THAKOR, NITISH V.; MIRSKI, MAREK A.; WHITE, MIRINDA ANDERSON; HINICH, MELVIN J.

    2011-01-01

    EEG and field potential rhythms established in the cortex and thalamus may accommodate the propagation of seizures. This article describes the interaction between thalamus and cortex during pentylenetetrazol (PTZ) seizures in rats with and without prior treatment with ethosuximide (ESM), a well-known antiepileptic drug (AED) that raises the threshold for seizures, was given before PTZ. The AED was given before PTZ convulsant administration. We track this thalamo-cortical association with a novel measure we have called the cross-bicoherence gain, or BISCOH. This quantity allows us to measure the spectral coherence in a purely higher order spectralmethodology. BISCOH is able to track the formation of nonlinearities at specific frequencies in the recorded EEG. BISCOH showed a strong increase in low alpha wave harmonic generationat 10 and 12.5 Hz after ESM treatment (p < 0.02 and p < 0.007, respectively). Conventional coherence failed to show distinctive and significant changes in thalamo-cortical coupling after ESM treatment at those frequencies and instead showed changes at 5 Hz. This rise in cortical rhythms is evidence of harmonic generation or new frequency formation in the thalamo-cortical system with AED therapy. BISCOH could become a powerful tool in unraveling changes in coherence due to neuroelectric modulation resulting from drug treatment or electrical stimulation. PMID:21442775

  9. Developmental phenotype of a membrane only estrogen receptor alpha (MOER) mouse.

    PubMed

    Pedram, Ali; Razandi, Mahnaz; Kim, Jin K; O'Mahony, Fiona; Lee, Eva Yhp; Luderer, Ulrike; Levin, Ellis R

    2009-02-01

    Estrogen receptors (ERs) alpha and beta exist as nuclear, cytoplasmic, and membrane cellular pools in a wide variety of organs. The relative contributions of each ERalpha pool to in vivo phenotypes resulting from estrogen signaling have not been determined. To address this, we generated a transgenic mouse expressing only a functional E domain of ERalpha at the plasma membrane (MOER). Cells isolated from many organs showed membrane only localized E domain of ERalpha and no other receptor pools. Liver cells from MOER and wild type mice responded to 17-beta-estradiol (E2) with comparable activation of ERK and phosphatidylinositol 3-kinase, not seen in cells from ERalphaKO mice. Mating the MOER female mice with proven male wild type breeders produced no pregnancies because the uterus and vagina of the MOER female mice were extremely atrophic. Ovaries of MOER and homozygous Strasbourg ERalphaKO mice showed multiple hemorrhagic cysts and no corpus luteum, and the mammary gland development in both MOER and ERalphaKO mice was rudimentary. Despite elevated serum E2 levels, serum LH was not suppressed, and prolactin levels were low in MOER mice. MOER and Strasbourg female mice showed plentiful abdominal visceral and other depots of fat and increased body weight compared to wild type mice despite comparable food consumption. These results provide strong evidence that the normal development and adult functions of important organs in female mice requires nuclear ERalpha and is not rescued by membrane ERalpha domain expression alone. PMID:19054762

  10. [Individual typological features of EEG response in the sportsman to acute hypoxia].

    PubMed

    Balioz, N V; Krivoshchekov, S G

    2012-01-01

    The paper investigated variability of individual EEG parametres: frequency of the maximum peak, width of a range and depth of reaction desynchronization (reduction alpha-rhythm of EEG at opening of eyes) in slowly increasing hypoxia from 20.9% to 10%-s' O2 of the sportsman with various types of physical activity and features of temperament. There were investigated 24 first-class athletes (11 swimmers, 13 skiers) aged 18-26 years. It is shown that dynamics of EEG rhythms during hypoxia, unlike normoxia, characterised by instability of spectral structure and phase during time of hypoxia test. It is established, that individual typological features (typology of nervous system) influence EEG response during hypoxic test. The negative relations between a psychological construct "endurance" for questionnaire (FCB-Ti) and feature alpha-rhythm EEG during hypoxia test are shown. The type of physical training and re-structuring pattern of breath (phenotypic adaptation) modulates sensitivity of brain structures to hypoxia which is reflected in dynamics alpha-rhythm of EEG in hypoxic conditions. PMID:23101237

  11. Splicing mutation in the ATR-X gene can lead to a dysmorphic mental retardation phenotype without {alpha}-thalassemia

    SciTech Connect

    Villard, L.; Lossi, A.M.; Fontes, M.

    1996-03-01

    We have previously reported the isolation of a gene from Xq13 that codes for a putative regulator of transcription (XNP) and has now been shown to be the gene involved in the X-linked {alpha}-thalassemia with mental retardation (ATR-X) syndrome. The widespread expression and numerous domains present in the putative protein suggest that this gene could be involved in other phenotypes. The predominant expression of the gene in the developing brain, as well as its association with neuron differentiation, indicates that mutations of this gene might result in a mental retardation (MR) phenotype. In this paper we present a family with a splice junction mutation in XNP that results in the skipping of an exon and in the introduction of a stop codon in the middle of the XNP-coding sequence. Only the abnormal transcript is expressed in two first cousins presenting the classic ATR-X phenotype (with {alpha}-thalassemia and HbH inclusions). In a distant cousin presenting a similar dysmorphic MR phenotype but not having thalassemia, {approximately}30% of the XNP transcripts are normal. These data demonstrate that the mode of action of the XNP gene product on globin expression is distinct from its mode of action in brain development and facial morphogenesis and suggest that other dysmorphic mental retardation phenotypes, such as Juberg-Marsidi or some sporadic cases of Coffin-Lowry, could be due to mutations in XNP. 20 refs., 5 figs., 2 tabs.

  12. Regional electroencephalogram (EEG) alpha power and asymmetry in older adults: a study of short-term test–retest reliability

    PubMed Central

    Mathewson, Karen J.; Hashemi, Ali; Sheng, Bruce; Sekuler, Allison B.; Bennett, Patrick J.; Schmidt, Louis A.

    2015-01-01

    Although regional alpha power and asymmetry measures have been widely used as indices of individual differences in emotional processing and affective style in younger populations, there have been relatively few studies that have examined these measures in older adults. Here, we examined the short-term test–retest reliability of resting regional alpha power (7.5–12.5 Hz) and asymmetry in a sample of 38 active, community-dwelling older adults (M age = 71.2, SD = 6.5 years). Resting electroencephalogram recordings were made before and after a perceptual computer task. Pearson and intra-class correlations indicated acceptable test–retest reliability for alpha power and asymmetry measures in all regions. Interestingly, alpha asymmetry appeared to be less affected by the task than was alpha power. Findings suggest that alpha asymmetry may reflect more enduring, “trait-like” characteristics, while alpha power may reflect more “state-like” processes in older adults. PMID:26441639

  13. EEG synchronization and migraine

    NASA Astrophysics Data System (ADS)

    Stramaglia, Sebastiano; Angelini, Leonardo; Pellicoro, Mario; Hu, Kun; Ivanov, Plamen Ch.

    2004-03-01

    We investigate phase synchronization in EEG recordings from migraine patients. We use the analytic signal technique, based on the Hilbert transform, and find that migraine brains are characterized by enhanced alpha band phase synchronization in presence of visual stimuli. Our findings show that migraine patients have an overactive regulatory mechanism that renders them more sensitive to external stimuli.

  14. Auditory cortical deactivation during speech production and following speech perception: an EEG investigation of the temporal dynamics of the auditory alpha rhythm

    PubMed Central

    Jenson, David; Harkrider, Ashley W.; Thornton, David; Bowers, Andrew L.; Saltuklaroglu, Tim

    2015-01-01

    Sensorimotor integration (SMI) across the dorsal stream enables online monitoring of speech. Jenson et al. (2014) used independent component analysis (ICA) and event related spectral perturbation (ERSP) analysis of electroencephalography (EEG) data to describe anterior sensorimotor (e.g., premotor cortex, PMC) activity during speech perception and production. The purpose of the current study was to identify and temporally map neural activity from posterior (i.e., auditory) regions of the dorsal stream in the same tasks. Perception tasks required “active” discrimination of syllable pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required overt production of syllable pairs and nouns. ICA performed on concatenated raw 68 channel EEG data from all tasks identified bilateral “auditory” alpha (α) components in 15 of 29 participants localized to pSTG (left) and pMTG (right). ERSP analyses were performed to reveal fluctuations in the spectral power of the α rhythm clusters across time. Production conditions were characterized by significant α event related synchronization (ERS; pFDR < 0.05) concurrent with EMG activity from speech production, consistent with speech-induced auditory inhibition. Discrimination conditions were also characterized by α ERS following stimulus offset. Auditory α ERS in all conditions temporally aligned with PMC activity reported in Jenson et al. (2014). These findings are indicative of speech-induced suppression of auditory regions, possibly via efference copy. The presence of the same pattern following stimulus offset in discrimination conditions suggests that sensorimotor contributions following speech perception reflect covert replay, and that covert replay provides one source of the motor activity previously observed in some speech perception tasks. To our knowledge, this is the first time that inhibition of auditory regions by speech has been observed in real-time with the ICA/ERSP technique. PMID

  15. [IMPACT OF INDIVIDUAL PERSONALITY FEATURES ON ABILITY TO VOLUNTARY REGULATION OF EXPRESSION EEG ALPHA AND BETA FREQUENCIES].

    PubMed

    Aslanyan, E V; Kiroy, V N; Stoletniy, A S; Lazurenko, D M; Bahtin, O M; Minyaeva, N R; Kiroy, R I

    2015-05-01

    The ability to voluntary control severity of alpha- and beta-2 frequency bands in the parietal and frontal cortical areas was investigated at 17 volunteers using biofeedback. The impact of different personality traits on the effectiveness of control was evaluated. According to the data, it was easier task to decrease expression beta-2 frequency in the frontal cortex than to decline the power of alpha frequency in the parietal cortex. The effectiveness of voluntary control of brain activity is influenced by personality features as extraversion, psychoticism, neuroticism, mobility and steadiness of nerve processes, level of person anxiety. PMID:26263685

  16. COMT polymorphism modulates the resting-state EEG alpha oscillatory response to acute nicotine in male non-smokers

    PubMed Central

    Bowers, H.; Smith, D.; de la Salle, S.; Choueiry, J.; Impey, D.; Philippe, T.; Dort, H.; Millar, A.; Daigle, M.; Albert, P. R.; Beaudoin, A.; Knott, V.

    2015-01-01

    Performance improvements in cognitive tasks requiring executive functions are evident with nicotinic acetylcholine receptor (nAChR) agonists, and activation of the underlying neural circuitry supporting these cognitive effects is thought to involve dopamine neurotransmission. As individual difference in response to nicotine may be related to a functional polymorphism in the gene encoding catechol-O-methyltransferase (COMT), an enzyme that strongly influences cortical dopamine metabolism, this study examined the modulatory effects of the COMT Val158Met polymorphism on the neural response to acute nicotine as measured with resting-state electroencephalographic (EEG) oscillations. In a sample of 62 healthy non-smoking adult males, a single dose (6 mg) of nicotine gum administered in a randomized, double-blind, placebo-controlled design was shown to affect α oscillatory activity, increasing power of upper α oscillations in frontocentral regions of Met/Met homozygotes and in parietal/occipital regions of Val/Met heterozygotes. Peak α frequency was also found to be faster with nicotine (vs. placebo) treatment in Val/Met heterozygotes, who exhibited a slower α frequency compared to Val/Val homozygotes. The data tentatively suggest that interindividual differences in brain α oscillations and their response to nicotinic agonist treatment are influenced by genetic mechanisms involving COMT. PMID:26096691

  17. Hb Oegstgeest [alpha104(G11)Cys-->Ser (alpha1)]. A new hemoglobin variant associated with a mild alpha-thalassemia phenotype.

    PubMed

    Harteveld, Cornelis L; Rozendaal, Lieke; Blom, Nico A; Lo-A-Njoe, Shirley; Akkerman, Nicole; Arkestijn, Sandra; Van Delft, Peter; Giordano, Piero C

    2005-01-01

    A microcytic hypochromic anemic state was observed in an 8-year old Black female of Surinam origin during pre-operative Hb S [beta6(A3)Glu-->Val] screening. Her high zinc protoporphyrin (ZPP) level suggested a chronic iron depletion but, in contrast, the high red blood cell (RBC) count (5.85 x 10(12)/L) was indicative of a possible coexisting thalassemia. No abnormal hemoglobin (Hb) bands were present on high performance liquid chromatography (HPLC) or alkaline electrophoresis and the Hb A2 level was normal. Break point polymerase chain reaction (PCR) failed to reveal any of the common alpha-thalassemia (thal) mutations but selective DNA sequencing of both alpha-globin genes disclosed a TGC-->AGC transversion at codon 104 of the alpha1 gene. Cystine at codon 104 is involved in alpha/beta globin contact and has been described to be a critical amino acid of the alpha2 chain when substituted by a tyrosine (Hb Sallanches), inducing Hb H (beta4) disease in the homozygous state. Our heterozygous patient had a moderate anemia of 12.2 g/dL and a borderline haptoglobin suggesting some degree of hemolysis. PMID:16114179

  18. PEG-IFN Alpha but Not Ribavirin Alters NK Cell Phenotype and Function in Patients with Chronic Hepatitis C

    PubMed Central

    Markova, Antoaneta A.; Mihm, Ulrike; Schlaphoff, Verena; Lunemann, Sebastian; Filmann, Natalie; Bremer, Birgit; Berg, Thomas; Sarrazin, Christoph; Zeuzem, Stefan; Manns, Michael P.; Cornberg, Markus; Herrmann, Eva; Wedemeyer, Heiner

    2014-01-01

    Background Ribavirin (RBV) remains part of several interferon-free treatment strategies even though its mechanisms of action are still not fully understood. One hypothesis is that RBV increases responsiveness to type I interferons. Pegylated Interferon alpha (PEG-IFNa) has recently been shown to alter natural killer (NK) cell function possibly contributing to control of hepatitis C virus (HCV) infection. However, the effects of ribavirin alone or in combination with IFNa on NK cells are unknown. Methods Extensive ex vivo phenotyping and functional analysis of NK cells from hepatitis C patients was performed during antiviral therapy. Patients were treated for 6 weeks with RBV monotherapy (n = 11), placebo (n = 13) or PEG-IFNa-2a alone (n = 6) followed by PEG-IFNa/RBV combination therapy. The effects of RBV and PEG-IFNa-2a on NK cells were also studied in vitro after co-culture with K562 or Huh7.5 cells. Results Ribavirin monotherapy had no obvious effects on NK cell phenotype or function, neither ex vivo in patients nor in vitro. In contrast, PEG-IFNa-2a therapy was associated with an increase of CD56bright cells and distinct changes in expression profiles leading to an activated NK cell phenotype, increased functionality and decline of terminally differentiated NK cells. Ribavirin combination therapy reduced some of the IFN effects. An activated NK cell phenotype during therapy was inversely correlated with HCV viral load. Conclusions PEG-IFNa activates NK cells possibly contributing to virological responses independently of RBV. The role of NK cells during future IFN-free combination therapies including RBV remains to be determined. PMID:24751903

  19. Association of ER-alpha gene polymorphism with metabolic phenotypes in Chinese Hans.

    PubMed

    Chen, Yan; Jiang, Xiao-yan; Xu, Li; Li, Xia; Cao, Fei-fei; Li, Lei; Lu, Ming; Jin, Li; Wang, Xiao-feng

    2009-08-01

    Recently, two polymorphisms (rs1884052 and rs3778099) of estrogen receptor alpha (ER-alpha) gene were identified as being associated with primary quantitative bone mineral density (BMD) in a genome-wide association (GWA) study in Framingham cohorts. In this study we aimed at investigating the association of rs1884052 and rs3778099, and another polymorphism (rs2234693) located at intron 1 of the ER-alpha gene with BMD, body mass index (BMI), glucose, triglyceride, and total cholesterol (CHO) levels in Chinese Hans. We recruited 425 consecutive adult volunteers who had a physical examination in the Jinan Maternity and Child Care Hospital. We did not observe significant association of rs1884052 and rs3778099 with BMD, BMI, glucose, triglyceride, and total cholesterol (CHO) levels. For rs2234693, increased levels of BMD for hip, spine or whole-body regions were consistently observed in TT/TC genotype carriers than in CC genotype carriers, although the board line significance diminished after adjusting for age and gender. However, significant association of rs2234693 with glucose and CHO levels were observed in our sample. Subjects with TC/CC genotypes were associated with an increased level of glucose (p = 0.013) and CHO (p = 0.032) levels than subjects with TT genotypes. In conclusion, we did not confirm the association of rs1884052 and rs3778099 with BMD originally discovered in a GWA study; however, we made novel discoveries that rs2234693 was associated with glucose and CHO levels in Chinese Hans. PMID:19578917

  20. Benzyl-N-acetyl-alpha-D-galactosaminide induces a storage disease-like phenotype by perturbing the endocytic pathway.

    PubMed

    Ulloa, Fausto; Real, Francisco X

    2003-04-01

    The sugar analog O-benzyl-N-acetyl-alpha-d-galactosaminide (BG) is an inhibitor of glycan chain elongation and inhibits alpha2,3-sialylation in mucus-secreting HT-29 cells. Long-term exposure of these cells to BG is associated with the accumulation of apical glycoproteins in cytoplasmic vesicles. The mechanisms involved therein and the nature of the vesicles have not been elucidated. In these cells, a massive amount of BG metabolites is synthesized. Because sialic acid is mainly distributed apically in epithelial cells, it has been proposed that the BG-induced undersialylation of apical membrane glycoproteins is responsible for their intracellular accumulation due to a defect in anterograde traffic and that sialic acid may constitute an apical targeting signal. In this work, we demonstrate that the intracellular accumulation of membrane glycoproteins does not result mainly from defects in anterograde traffic. By contrast, in BG-treated cells, endocytosed membrane proteins were retained intracellularly for longer periods of time than in control cells and colocalized with accumulated MUC1 and beta(1) integrin in Rab7/lysobisphosphatidic acid(+) vesicles displaying features of late endosomes. The phenotype of BG-treated cells is reminiscent of that observed in lysosomal storage disorders. Sucrose induced a BG-like, lysosomal storage disease-like phenotype without affecting sialylation, indicating that undersialylation is not a requisite for the intracellular accumulation of membrane glycoproteins. Our findings strongly support the notion that the effects observed in BG-treated cells result from the accumulation of BG-derived metabolites and from defects in the endosomal pathway. We propose that abnormal subcellular distribution of membrane glycoproteins involved in cellular communication and/or signaling may also take place in lysosomal storage disorders and may contribute to their pathogenesis. PMID:12538583

  1. Intravenous administration of alpha-1-proteinase inhibitor in patients of PiZ and PiM phenotype. Preliminary report

    SciTech Connect

    Moser, K.M.; Smith, R.M.; Spragg, R.G.; Tisi, G.M.

    1988-06-24

    Nine patients with moderate pulmonary emphysema, six of PiZ phenotype and three of PiM phenotype, have received a single intravenous infusion of alpha-1-proteinase inhibitor (human) (A1PI), in a dose of 60 mg/kg over a 30-minute period. They also received a tracer dose (300 microCi) of /sup 131/I-labeled A1PI. No active or passive immunization against hepatitis was given. No acute toxicity was observed. Compared with baseline data, significant elevations of serum A1PI (measured both antigenically and as anti-elastase activity) occurred, with a serum half-life approximating 110 hours. Bronchoalveolar lavage fluid, obtained 48 hours after infusion, reflected a significant increase in A1PI concentration versus baseline bronchoalveolar lavage fluid values. Serial gamma camera images of the lungs confirmed persistence of enhanced lung radioactivity for several days. Urinary desmosine excretion did not change following A1PI infusion. During the period of follow-up thus far, no patient has had chronic toxicity, results of liver function tests have been stable, and there has been no development of hepatitis B antigen or antibodies to hepatitis B surface or core antigens.

  2. [Computerized EEG and personality].

    PubMed

    Ramírez Pérez, A; Martínez López-Coterilla, M; Fajardo López, A; Lardelli Claret, A

    1989-01-01

    The ordinary EEG, on only showing qualitative malfunction of abnormal graphoelements in the tracings, proves itself insufficient to go into the analysis of psychological and psycho-pathological problems. Since computerised studies of EEG permit quantitative comparisons, we tried to apply them in correlation with the characteristics of the personality classified also with quantitative criteria, such as those offered in the personality inventory 16 PF; from which have been chosen the so-called factors of the second order, and the subjectivity-objectivity factors. The test was carried out on 100 voluntary subjects from Almeria (Spain), all with High School grades, between 18 and 40 years of age, of both sexes, all right-handed, without neuro-psychiatric history, and with normal ordinary EEGs. From the statistical analysis of the results one could deduce that there are significant specific relationships from the computerised EEG, with those secondary polar values of 16 PF: high and low anxiety, extroversion-introversion. Subjects with low anxiety presented a significant increase of the alpha band opposed to the subjects with high anxiety. There is a significant differences in power of the frontal areas between extrovert and introvert subjects. The extroverted subjects have a greater power of the right side and the introverted subjects a greater power of the left. PMID:2698596

  3. Human cholesterol 7alpha-hydroxylase (CYP7A1) deficiency has a hypercholesterolemic phenotype.

    PubMed

    Pullinger, Clive R; Eng, Celeste; Salen, Gerald; Shefer, Sarah; Batta, Ashok K; Erickson, Sandra K; Verhagen, Andrea; Rivera, Christopher R; Mulvihill, Sean J; Malloy, Mary J; Kane, John P

    2002-07-01

    Bile acid synthesis plays a critical role in the maintenance of mammalian cholesterol homeostasis. The CYP7A1 gene encodes the enzyme cholesterol 7alpha-hydroxylase, which catalyzes the initial step in cholesterol catabolism and bile acid synthesis. We report here a new metabolic disorder presenting with hyperlipidemia caused by a homozygous deletion mutation in CYP7A1. The mutation leads to a frameshift (L413fsX414) that results in loss of the active site and enzyme function. High levels of LDL cholesterol were seen in three homozygous subjects. Analysis of a liver biopsy and stool from one of these subjects revealed double the normal hepatic cholesterol content, a markedly deficient rate of bile acid excretion, and evidence for upregulation of the alternative bile acid pathway. Two male subjects studied had hypertriglyceridemia and premature gallstone disease, and their LDL cholesterol levels were noticeably resistant to 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. One subject also had premature coronary and peripheral vascular disease. Study of the kindred, which is of English and Celtic background, revealed that individuals heterozygous for the mutation are also hyperlipidemic, indicating that this is a codominant disorder. PMID:12093894

  4. Note on the EEG Orienting Response in Children.

    ERIC Educational Resources Information Center

    Bryan, Janice Westlund

    1982-01-01

    Durations of children's alpha bursts and alpha blocking were measured by EEG with eyes closed or open in the dark and with feedback visual stimulation. Alpha durations decreased across conditions. Older children had longer no-alpha durations and showed greater responsiveness to conditions. The alpha-blocking response changes during childhood.…

  5. “I am resting but rest less well with you.” The moderating effect of anxious attachment style on alpha power during EEG resting state in a social context

    PubMed Central

    Verbeke, Willem J. M. I.; Pozharliev, Rumen; Van Strien, Jan W.; Belschak, Frank; Bagozzi, Richard P.

    2014-01-01

    We took EEG recordings to measure task-free resting-state cortical brain activity in 35 participants under two conditions, alone (A) or together (T). We also investigated whether psychological attachment styles shape human cortical activity differently in these two settings. The results indicate that social context matters and that participants' cortical activity is moderated by the anxious, but not avoidant attachment style. We found enhanced alpha, beta and theta band activity in the T rather than the A resting-state condition, which was more pronounced in posterior brain regions. We further found a positive correlation between anxious attachment style and enhanced alpha power in the T vs. A condition over frontal and parietal scalp regions. There was no significant correlation between the absolute powers registered in the other two frequency bands and the participants' anxious attachment style. PMID:25071516

  6. Overexpression of synphilin-1 promotes clearance of soluble and misfolded alpha-synuclein without restoring the motor phenotype in aged A30P transgenic mice.

    PubMed

    Casadei, Nicolas; Pöhler, Anne-Maria; Tomás-Zapico, Cristina; Torres-Peraza, Jesús; Schwedhelm, Ivo; Witz, Annemarie; Zamolo, Irina; De Heer, Raymond; Spruijt, Berry; Noldus, Lucas P J J; Klucken, Jochen; Lucas, José J; Kahle, Philipp J; Krüger, Rejko; Riess, Olaf; Nuber, Silke

    2014-02-01

    Lewy bodies and neurites are the pathological hallmark of Parkinson's disease. These structures are composed of fibrillized and ubiquitinated alpha-synuclein suggesting that impaired protein clearance is an important event in aggregate formation. The A30P mutation is known for its fast oligomerization, but slow fibrillization rate. Despite its toxicity to neurons, mechanisms involved in either clearance or conversion of A30P alpha-synuclein from its soluble state into insoluble fibrils and their effects in vivo are poorly understood. Synphilin-1 is present in Lewy bodies, interacting with alpha-synuclein in vivo and in vitro and promotes its sequestration into aggresomes, which are thought to act as cytoprotective agents facilitating protein degradation. We therefore crossed animals overexpressing A30P alpha-synuclein with synphilin-1 transgenic mice to analyze its impact on aggregation, protein clearance and phenotype progression. We observed that co-expression of synphilin-1 mildly delayed the motor phenotype caused by A30P alpha-synuclein. Additionally, the presence of N- and C-terminal truncated alpha-synuclein species and fibrils were strongly reduced in double-transgenic mice when compared with single-transgenic A30P mice. Insolubility of mutant A30P and formation of aggresomes was still detectable in aged double-transgenic mice, paralleled by an increase of ubiquitinated proteins and high autophagic activity. Hence, this study supports the notion that co-expression of synphilin-1 promotes formation of autophagic-susceptible aggresomes and consecutively the degradation of human A30P alpha-synuclein. Notably, although synphilin-1 overexpression significantly reduced formation of fibrils and astrogliosis in aged animals, a similar phenotype is present in single- and double-transgenic mice suggesting additional neurotoxic processes in disease progression. PMID:24064336

  7. EEG Recorded from the Ear: Characterizing the Ear-EEG Method

    PubMed Central

    Mikkelsen, Kaare B.; Kappel, Simon L.; Mandic, Danilo P.; Kidmose, Preben

    2015-01-01

    Highlights Auditory middle and late latency responses can be recorded reliably from ear-EEG.For sources close to the ear, ear-EEG has the same signal-to-noise-ratio as scalp.Ear-EEG is an excellent match for power spectrum-based analysis. A method for measuring electroencephalograms (EEG) from the outer ear, so-called ear-EEG, has recently been proposed. The method could potentially enable robust recording of EEG in natural environments. The objective of this study was to substantiate the ear-EEG method by using a larger population of subjects and several paradigms. For rigor, we considered simultaneous scalp and ear-EEG recordings with common reference. More precisely, 32 conventional scalp electrodes and 12 ear electrodes allowed a thorough comparison between conventional and ear electrodes, testing several different placements of references. The paradigms probed auditory onset response, mismatch negativity, auditory steady-state response and alpha power attenuation. By comparing event related potential (ERP) waveforms from the mismatch response paradigm, the signal measured from the ear electrodes was found to reflect the same cortical activity as that from nearby scalp electrodes. It was also found that referencing the ear-EEG electrodes to another within-ear electrode affects the time-domain recorded waveform (relative to scalp recordings), but not the timing of individual components. It was furthermore found that auditory steady-state responses and alpha-band modulation were measured reliably with the ear-EEG modality. Finally, our findings showed that the auditory mismatch response was difficult to monitor with the ear-EEG. We conclude that ear-EEG yields similar performance as conventional EEG for spectrogram-based analysis, similar timing of ERP components, and equal signal strength for sources close to the ear. Ear-EEG can reliably measure activity from regions of the cortex which are located close to the ears, especially in paradigms employing frequency

  8. EEG Recorded from the Ear: Characterizing the Ear-EEG Method.

    PubMed

    Mikkelsen, Kaare B; Kappel, Simon L; Mandic, Danilo P; Kidmose, Preben

    2015-01-01

    Highlights Auditory middle and late latency responses can be recorded reliably from ear-EEG.For sources close to the ear, ear-EEG has the same signal-to-noise-ratio as scalp.Ear-EEG is an excellent match for power spectrum-based analysis. A method for measuring electroencephalograms (EEG) from the outer ear, so-called ear-EEG, has recently been proposed. The method could potentially enable robust recording of EEG in natural environments. The objective of this study was to substantiate the ear-EEG method by using a larger population of subjects and several paradigms. For rigor, we considered simultaneous scalp and ear-EEG recordings with common reference. More precisely, 32 conventional scalp electrodes and 12 ear electrodes allowed a thorough comparison between conventional and ear electrodes, testing several different placements of references. The paradigms probed auditory onset response, mismatch negativity, auditory steady-state response and alpha power attenuation. By comparing event related potential (ERP) waveforms from the mismatch response paradigm, the signal measured from the ear electrodes was found to reflect the same cortical activity as that from nearby scalp electrodes. It was also found that referencing the ear-EEG electrodes to another within-ear electrode affects the time-domain recorded waveform (relative to scalp recordings), but not the timing of individual components. It was furthermore found that auditory steady-state responses and alpha-band modulation were measured reliably with the ear-EEG modality. Finally, our findings showed that the auditory mismatch response was difficult to monitor with the ear-EEG. We conclude that ear-EEG yields similar performance as conventional EEG for spectrogram-based analysis, similar timing of ERP components, and equal signal strength for sources close to the ear. Ear-EEG can reliably measure activity from regions of the cortex which are located close to the ears, especially in paradigms employing frequency

  9. Refractory Classical Hodgkin Lymphoma Presenting with Atypical Cutaneous Involvement and Diagnosis of ZZ Phenotype Alpha-1 Antitrypsin Deficiency.

    PubMed

    Khawandanah, Mohamad; Kraus, Teresa; Cherry, Mohamad

    2014-01-01

    Cutaneous Hodgkin lymphoma is a rare condition. Specific neoplastic involvement can be primary (confined to the skin) or secondary to systemic involvement (metastatic). Cutaneous involvement by HL usually occurs late in the course and is associated with poor prognosis; however in some cases it can exhibit indolent behavior. Skin involvement with nonspecific cutaneous findings may represent a paraneoplastic syndrome. We describe a case of 46-year-old white male patient presented with rash and lymphadenopathy which led to the diagnosis of stage IVE mixed cellularity classical Hodgkin lymphoma with skin involvement. His disease was refractory to multiple lines of chemotherapy including (1) AVD (doxorubicin/bleomycin/dacarbazine), (2) brentuximab, and (3) bendamustine, he later achieved complete remission with (4) GCD (gemcitabine/carboplatin/dexamethasone) salvage regimen. Bleomycin was not given secondary to poor pulmonary function tests. His treatment was complicated after AVD with multiple pneumothoraces which unmasked the diagnosis of ZZ phenotype alpha-1 antitrypsin (ATT) deficiency. Simultaneous existence of Hodgkin lymphoma and ATT is rarely reported. PMID:24955265

  10. Genetic Analysis of the Pathogenic Molecular Sub-phenotype Interferon Alpha Identifies Multiple Novel Loci Involved in Systemic Lupus Erythematosus

    PubMed Central

    Kariuki, Silvia N.; Ghodke-Puranik, Yogita; Dorschner, Jessica M.; Chrabot, Beverly S.; Kelly, Jennifer A.; Tsao, Betty P.; Kimberly, Robert P.; Alarcón-Riquelme, Marta E.; Jacob, Chaim O.; Criswell, Lindsey A.; Sivils, Kathy L.; Langefeld, Carl D.; Harley, John B.; Skol, Andrew D.; Niewold, Timothy B.

    2014-01-01

    Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disorder characterized by inflammation of multiple organ systems and dysregulated interferon responses. SLE is both genetically and phenotypically heterogeneous, greatly reducing the power of case-control studies in SLE. Elevated circulating interferon alpha (IFN-α) is a stable, heritable trait in SLE, which has been implicated in primary disease pathogenesis. 40–50% of patients have high IFN-α, and high levels correspond with clinical differences. To study genetic heterogeneity in SLE, we performed a case-case study comparing patients with high vs. low IFN-α in over 1550 SLE cases, including GWAS and replication cohorts. In meta-analysis, the top associations in European ancestry were PRKG1 rs7897633 (PMeta=2.75 × 10−8) and PNP rs1049564 (PMeta=1.24 × 10−7). We also found evidence for cross-ancestral background associations with the ANKRD44 and PLEKHF2 loci. These loci have not been previously identified in case-control SLE genetic studies. Bioinformatic analyses implicated these loci functionally in dendritic cells and natural killer cells, both of which are involved in IFN-α production in SLE. As case-control studies of heterogeneous diseases reach a limit of feasibility with respect to subject number and detectable effect size, the study of informative pathogenic subphenotypes becomes an attractive strategy for genetic discovery in complex disease. PMID:25338677

  11. Concordance between distributed EEG source localization and simultaneous EEG-fMRI studies of epileptic spikes.

    PubMed

    Grova, C; Daunizeau, J; Kobayashi, E; Bagshaw, A P; Lina, J-M; Dubeau, F; Gotman, J

    2008-01-15

    In order to analyze where epileptic spikes are generated, we assessed the level of concordance between EEG source localization using distributed source models and simultaneous EEG-fMRI which measures the hemodynamic correlates of EEG activity. Data to be compared were first estimated on the same cortical surface and two comparison strategies were used: (1) MEM-concordance: a comparison between EEG sources localized with the Maximum Entropy on the Mean (MEM) method and fMRI clusters showing a significant hemodynamic response. Minimal geodesic distances between local extrema and overlap measurements between spatial extents of EEG sources and fMRI clusters were used to quantify MEM-concordance. (2) fMRI-relevance: estimation of the fMRI-relevance index alpha quantifying if sources located in an fMRI cluster could explain some scalp EEG data, when this fMRI cluster was used to constrain the EEG inverse problem. Combining MEM-concordance and fMRI-relevance (alpha) indexes, each fMRI cluster showing a significant hemodynamic response (p<0.05 corrected) was classified according to its concordance with EEG data. Nine patients with focal epilepsy who underwent EEG-fMRI examination followed by EEG recording outside the scanner were selected for this study. Among the 62 fMRI clusters analyzed (7 patients), 15 (24%) found in 6 patients were highly concordant with EEG according to both MEM-concordance and fMRI-relevance. EEG concordance was found for 5 clusters (8%) according to alpha only, suggesting sources missed by the MEM. No concordance with EEG was found for 30 clusters (48%) and for 10 clusters (16%) alpha was significantly negative, suggesting EEG-fMRI discordance. We proposed two complementary strategies to assess and classify EEG-fMRI concordance. We showed that for most patients, part of the hemodynamic response to spikes was highly concordant with EEG sources, whereas other fMRI clusters in response to the same spikes were found distant or discordant with EEG

  12. Memory activation enhances EEG abnormality in mild cognitive impairment.

    PubMed

    van der Hiele, K; Vein, A A; Kramer, C G S; Reijntjes, R H A M; van Buchem, M A; Westendorp, R G J; Bollen, E L E M; van Dijk, J G; Middelkoop, H A M

    2007-01-01

    This exploratory study investigated EEG power changes during memory activation in patients with amnestic mild cognitive impairment (MCI). Twelve MCI patients and 16 age-matched controls underwent EEG registration during two conventional EEG conditions ('eyes closed' and 'eyes open') and three memory conditions ('word memory', 'picture memory' and 'animal fluency'). For all conditions, EEG power in the theta (4-8 Hz), lower alpha (8-10.5 Hz) and upper alpha (10.5-13 Hz) bands were expressed as percentile changes compared to 'eyes closed'. MCI patients showed significantly less decrease in the lower alpha band than controls (p=0.04) during picture memory activation. The word memory task showed a trend towards a similar effect (p=0.09). This study suggests that memory activation reveals EEG differences between MCI patients and controls while conventional EEG conditions do not. PMID:16406153

  13. Test-retest reliability of cognitive EEG

    NASA Technical Reports Server (NTRS)

    McEvoy, L. K.; Smith, M. E.; Gevins, A.

    2000-01-01

    OBJECTIVE: Task-related EEG is sensitive to changes in cognitive state produced by increased task difficulty and by transient impairment. If task-related EEG has high test-retest reliability, it could be used as part of a clinical test to assess changes in cognitive function. The aim of this study was to determine the reliability of the EEG recorded during the performance of a working memory (WM) task and a psychomotor vigilance task (PVT). METHODS: EEG was recorded while subjects rested quietly and while they performed the tasks. Within session (test-retest interval of approximately 1 h) and between session (test-retest interval of approximately 7 days) reliability was calculated for four EEG components: frontal midline theta at Fz, posterior theta at Pz, and slow and fast alpha at Pz. RESULTS: Task-related EEG was highly reliable within and between sessions (r0.9 for all components in WM task, and r0.8 for all components in the PVT). Resting EEG also showed high reliability, although the magnitude of the correlation was somewhat smaller than that of the task-related EEG (r0.7 for all 4 components). CONCLUSIONS: These results suggest that under appropriate conditions, task-related EEG has sufficient retest reliability for use in assessing clinical changes in cognitive status.

  14. Differential regulation of T helper phenotype development by interleukins 4 and 10 in an alpha beta T-cell-receptor transgenic system.

    PubMed Central

    Hsieh, C S; Heimberger, A B; Gold, J S; O'Garra, A; Murphy, K M

    1992-01-01

    To address the mechanisms controlling T helper (Th) phenotype development, we used DO10, a transgenic mouse line that expresses the alpha beta T-cell receptor from an ovalbumin-reactive T hybridoma, as a source of naive T cells that can be stimulated in vitro with ovalbumin peptide presented by defined antigen-presenting cells (APCs). We have examined the role of cytokines and APCs in the regulation of Th phenotype development. Interleukin 4 (IL-4) directs development toward the Th2 phenotype, stimulating IL-4 and silencing IL-2 and interferon gamma production in developing T cells. Splenic APCs direct development toward the Th1 phenotype when endogenous IL-10 is neutralized with anti-IL-10 antibody. The splenic APCs mediating these effects are probably macrophages or dendritic cells and not B cells, since IL-10 is incapable of affecting Th phenotype development when the B-cell hybridoma TA3 is used as the APC. These results suggest that early regulation of IL-4 and IL-10 in a developing immune response and the identity of the initiating APCs are critical in determining the Th phenotype of the developing T cells. PMID:1385868

  15. Alpha-thalassemia intellectual disability: variable phenotypic expression among males with a recurrent nonsense mutation - c.109C>T (p.R37X).

    PubMed

    Basehore, M J; Michaelson-Cohen, R; Levy-Lahad, E; Sismani, C; Bird, L M; Friez, M J; Walsh, T; Abidi, F; Holloway, L; Skinner, C; McGee, S; Alexandrou, A; Syrrou, M; Patsalis, P C; Raymond, G; Wang, T; Schwartz, C E; King, M-C; Stevenson, R E

    2015-05-01

    Alpha-thalassemia intellectual disability, one of the recognizable X-linked disability syndromes, is characterized by short stature, microcephaly, distinctive facies, hypotonic appearance, cardiac and genital anomalies, and marked skewing of X-inactivation in female carriers. With the advent of next generation sequencing, mutations have been identified that result in less severe phenotypes lacking one or more of these phenotypic manifestations. Here we report five unrelated kindreds in which a c.109C>T (p.R37X) mutation segregates with a variable but overall milder phenotype. The distinctive facial appearance of alpha-thalassemia intellectual disability was present in only one of the 18 affected males evaluated beyond the age of puberty, although suggestive facial appearance was present in several during infancy or early childhood. Although the responsible genetic alteration is a nonsense mutation in exon 2 of ATRX, the phenotype appears to be partially rescued by the production of alternative transcripts and/or other molecular mechanisms. PMID:24805811

  16. Learning abilities, NGF and BDNF brain levels in two lines of TNF-alpha transgenic mice, one characterized by neurological disorders, the other phenotypically normal.

    PubMed

    Aloe, L; Properzi, F; Probert, L; Akassoglou, K; Kassiotis, G; Micera, A; Fiore, M

    1999-09-01

    In this study we used two lines of transgenic mice overexpressing tumor necrosis factor alpha (TNF-alpha) in the central nervous system (CNS), one characterized by reactive gliosis, inflammatory demyelination and neurological deficits (Tg6074) the other showing no neurological or phenotypical alterations (TgK3) to investigate the effect of TNF-alpha on brain nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) levels and learning abilities. The results showed that the amount of NGF in the brain of Tg6074 and TgK3 transgenic mice is low in the hippocampus and in the spinal cord, increases in the hypothalamus of Tg6074 and showed no significant changes in the cortex. BDNF levels were low in the hippocampus and spinal cord of TgK3. BDNF increased in the hypothalamus of TgK3 and Tg6074 while in the cortex, BDNF increased only in Tg6074 mice. Transgenic mice also had memory impairments as revealed by the Morris Water Maze test. These findings indicate that TNF-alpha significantly influences BDNF and NGF synthesis, most probably in a dose-dependent manner. Learning abilities were also differently affected by overexpression of TNF-alpha, but were not associated with inflammatory activity. The possible functional implications of our findings are discussed. PMID:10517960

  17. Memory activation reveals abnormal EEG in preclinical Huntington's disease.

    PubMed

    van der Hiele, Karin; Jurgens, Caroline K; Vein, Alla A; Reijntjes, Robert H A M; Witjes-Ané, Marie-Noëlle W; Roos, Raymund A C; van Dijk, Gert; Middelkoop, Huub A M

    2007-04-15

    The EEG is potentially useful as a marker of early Huntington's disease (HD). In dementia, the EEG during a memory activation challenge showed abnormalities where the resting EEG did not. We investigated whether memory activation also reveals EEG abnormalities in preclinical HD. Sixteen mutation carriers for HD and 13 nonmutation carriers underwent neurological, neuropsychological, MRI and EEG investigations. The EEG was registered during a rest condition, i.e. eyes closed, and a working memory task. In each condition we determined absolute power in the theta (4-8 Hz) and alpha (8-13 Hz) bands and subsequently calculated relative alpha power. The EEG during eyes closed did not differ between groups. The EEG during memory activation showed less relative alpha power in mutation carriers as compared to nonmutation carriers, even though memory performance was similar [F (1,27) = 10.87; P = 0.003]. Absolute powers also showed less alpha power [F (1,27) = 7.02; P = 0.013] but similar theta power. No correlations were found between absolute and relative alpha power on the one hand and neuropsychological scores, motor scores or number of CAG repeats on the other. In conclusion, memory activation reveals functional brain changes in Huntington's disease before clinical signs become overt. PMID:17266047

  18. A low-power, wireless, 8-channel EEG monitoring headset.

    PubMed

    Brown, Lindsay; van de Molengraft, Jef; Yazicioglu, Refet Firat; Torfs, Tom; Penders, Julien; Van Hoof, Chris

    2010-01-01

    Micro- and nano-technology has enabled development of smaller and smarter wearable devices for medical and lifestyle related applications. In particular, recent advances in EEG monitoring technologies pave the way for wearable, wireless EEG monitoring devices. Here, a low-power wireless EEG sensor platform that measures 8-channels of EEG, is described. The platform is integrated into a wearable headset for ambulatory monitoring of EEG. While using standard EEG electrodes without conductive gel, a first evaluation shows the wireless headset is comparable to the reference system when looking at alpha wave discrimination. This device combines low-noise, and low-power functionality into an easy-to-use wireless headset, providing a first step towards a fully integrated, fully functional wearable wireless EEG monitoring system. PMID:21096892

  19. Effects of 2G and 3G mobile phones on human alpha rhythms: Resting EEG in adolescents, young adults, and the elderly.

    PubMed

    Croft, R J; Leung, S; McKenzie, R J; Loughran, S P; Iskra, S; Hamblin, D L; Cooper, N R

    2010-09-01

    The present study was conducted to determine whether adolescents and/or the elderly are more sensitive to mobile phone (MP)-related bioeffects than young adults, and to determine this for both 2nd generation (2G) GSM, and 3rd generation (3G) W-CDMA exposures. To test this, resting alpha activity (8-12 Hz band of the electroencephalogram) was assessed because numerous studies have now reported it to be enhanced by MP exposure. Forty-one 13-15 year olds, forty-two 19-40 year olds, and twenty 55-70 year olds were tested using a double-blind crossover design, where each participant received Sham, 2G and 3G exposures, separated by at least 4 days. Alpha activity, during exposure relative to baseline, was recorded and compared between conditions. Consistent with previous research, the young adults' alpha was greater in the 2G compared to Sham condition, however, no effect was seen in the adolescent or the elderly groups, and no effect of 3G exposures was found in any group. The results provide further support for an effect of 2G exposures on resting alpha activity in young adults, but fail to support a similar enhancement in adolescents or the elderly, or in any age group as a function of 3G exposure. PMID:20564174

  20. Hyperekplexia phenotype of glycine receptor alpha1 subunit mutant mice identifies Zn(2+) as an essential endogenous modulator of glycinergic neurotransmission.

    PubMed

    Hirzel, Klaus; Müller, Ulrike; Latal, A Tobias; Hülsmann, Swen; Grudzinska, Joanna; Seeliger, Mathias W; Betz, Heinrich; Laube, Bodo

    2006-11-22

    Zn(2+) is thought to modulate neurotransmission by affecting currents mediated by ligand-gated ion channels and transmitter reuptake by Na(+)-dependent transporter systems. Here, we examined the in vivo relevance of Zn(2+) neuromodulation by producing knockin mice carrying the mutation D80A in the glycine receptor (GlyR) alpha1 subunit gene (Glra1). This substitution selectively eliminates the potentiating effect of Zn(2+) on GlyR currents. Mice homozygous for Glra1(D80A) develop a severe neuromotor phenotype postnatally that resembles forms of human hyperekplexia (startle disease) caused by mutations in GlyR genes. In spinal neurons and brainstem slices from Glra1(D80A) mice, GlyR expression, synaptic localization, and basal glycinergic transmission were normal; however, potentiation of spontaneous glycinergic currents by Zn(2+) was significantly impaired. Thus, the hyperekplexia phenotype of Glra1(D80A) mice is due to the loss of Zn(2+) potentiation of alpha1 subunit containing GlyRs, indicating that synaptic Zn(2+) is essential for proper in vivo functioning of glycinergic neurotransmission. PMID:17114051

  1. The effects of centrally acting drugs on the EEG correlates of meditation.

    PubMed

    Sim, M K; Tsoi, W F

    1992-09-01

    The present study investigated the effects of three centrally acting drugs on the significant increase in the intermediate alpha frequency of the electroencephalogram (EEG) that accompanied meditation in a male volunteer. When compared to the EEG recorded before each of the three drugs was administered, naloxone tended to enhance the increase in the power of the intermediate alpha EEG (9.4-10.4 Hz), while diazepam tended to spread the increase to the slow (7.4-9.4 Hz) alpha EEG, and flumazenil was without much effect on the overall EEG pattern. However, these EEG changes when compared to similar changes obtained with saline administration were not significantly different from the latter. Thus, it is unlikely that the EEG correlates of meditation are causally related to the rise or fall of endogenous opioid peptides or benzodiazepinelike substances in the brain. PMID:1515478

  2. Making waves in the stream of consciousness: entraining oscillations in EEG alpha and fluctuations in visual awareness with rhythmic visual stimulation.

    PubMed

    Mathewson, Kyle E; Prudhomme, Christopher; Fabiani, Monica; Beck, Diane M; Lleras, Alejandro; Gratton, Gabriele

    2012-12-01

    Rhythmic events are common in our sensory world. Temporal regularities could be used to predict the timing of upcoming events, thus facilitating their processing. Indeed, cognitive theories have long posited the existence of internal oscillators whose timing can be entrained to ongoing periodic stimuli in the environment as a mechanism of temporal attention. Recently, recordings from primate brains have shown electrophysiological evidence for these hypothesized internal oscillations. We hypothesized that rhythmic visual stimuli can entrain ongoing neural oscillations in humans, locking the timing of the excitability cycles they represent and thus enhancing processing of subsequently predictable stimuli. Here we report evidence for entrainment of neural oscillations by predictable periodic stimuli in the alpha frequency band and show for the first time that the phase of existing brain oscillations cannot only be modified in response to rhythmic visual stimulation but that the resulting phase-locked fluctuations in excitability lead to concomitant fluctuations in visual awareness in humans. This entrainment effect was dependent on both the amount of spontaneous alpha power before the experiment and the level of 12-Hz oscillation before each trial and could not be explained by evoked activity. Rhythmic fluctuations in awareness elicited by entrainment of ongoing neural excitability cycles support a proposed role for alpha oscillations as a pulsed inhibition of cortical activity. Furthermore, these data provide evidence for the quantized nature of our conscious experience and reveal a powerful mechanism by which temporal attention as well as perceptual snapshots can be manipulated and controlled. PMID:22905825

  3. The Mozart Effect: A quantitative EEG study.

    PubMed

    Verrusio, Walter; Ettorre, Evaristo; Vicenzini, Edoardo; Vanacore, Nicola; Cacciafesta, Mauro; Mecarelli, Oriano

    2015-09-01

    The aim of this study is to investigate the influence of Mozart's music on brain activity through spectral analysis of the EEG in young healthy adults (Adults), in healthy elderly (Elderly) and in elderly with Mild Cognitive Impairment (MCI). EEG recording was performed at basal rest conditions and after listening to Mozart's K448 or "Fur Elise" Beethoven's sonatas. After listening to Mozart, an increase of alpha band and median frequency index of background alpha rhythm activity (a pattern of brain wave activity linked to memory, cognition and open mind to problem solving) was observed both in Adults and in Elderly. No changes were observed in MCI. After listening to Beethoven, no changes in EEG activity were detected. This results may be representative of the fact that said Mozart's music is able to "activate" neuronal cortical circuits related to attentive and cognitive functions. PMID:26036835

  4. [Qualitative and quantitative EEG-findings in schizophrenia (author's transl)].

    PubMed

    Itil, T M

    1978-03-01

    The results of the qualitative but particularly the quantitative EEG-studies indicate that 1. The EEG of adult schizophrenics is characterized by an appearance of excessive fast activity along with some slow waves and the lack of alpha-activity. 2. Excessive fast activity and lack of alpha-waves have also been found in the EEGs of psychotic children and most interestingly in children whose parents (particularly the mother) are schizophrenic (high risk children). 3. Based on the studies during sleep and investigations with neuroleptics, it was established that the origin of the excess fast activity in schizophrenia cannot be the muscle potential. Particularly the excess fast activity in high risk children for schizophrenia goes against the muscle potential hypothesis. 4. The quantitative EEG changes seen in schizophrenia show similarity to those seen after hallucinogenic compounds particularly after anticholinergic hallucinogenics. 5. All neuroleptics (major tranquilizers) produce quantitative EEG alterations which are almost diametrically opposite to those seen in schizoprenia. PMID:416942

  5. Development of the EEG measurement method under exercising.

    PubMed

    Dobashi, Noriyuki; Magatani, Kazushige

    2009-01-01

    It is said that the result of the game of sports is controlled by player's mental state. Especially, player's concentration greatly controls the result of the game. Therefore, we think that if player's mental state under exercising can be evaluated, it becomes possible to guide the player appropriately. Our mental state can be understood from analyzing EEG (Electroencephalogram). Especially, it is said that the change of alpha and beta rhythm of EEG will indicate the change of human's mental state. Therefore, we think that if EEG of the athlete can be measured under exercising, it becomes possible to evaluate mental state of the athlete. However, EEG is measured in the state of the rest usually, and measuring EEG under exercising is difficult. Because, the amplitude of EEG is very small and high amplification is necessary to obtain observable EEG. A movement of the body causes vibration of electrodes, and these vibration cause artifact of EEG. So, our objective of this study is a development of the new measuring method of EEG under exercising. In this paper, we will talk about our developed EEG measuring system for athletes. This system measures EEG and acceleration of the athlete's body. These measured data are sent to the receiver by a FM transmitter. Received data are analyzed with the personal computer, and the EEG and the noise are separated. Some normal subjects were tested with our developed system. From these experiments, it was clarified that our system had some problems. However, EEG with little noise was able to be obtained in all cases. Therefore, we think that if these problems are improved, our developed system will become useful for the measurement of EEG under exercising. PMID:19964931

  6. EEG oscillations: From correlation to causality.

    PubMed

    Herrmann, Christoph S; Strüber, Daniel; Helfrich, Randolph F; Engel, Andreas K

    2016-05-01

    Already in his first report on the discovery of the human EEG in 1929, Berger showed great interest in further elucidating the functional roles of the alpha and beta waves for normal mental activities. Meanwhile, most cognitive processes have been linked to at least one of the traditional frequency bands in the delta, theta, alpha, beta, and gamma range. Although the existing wealth of high-quality correlative EEG data led many researchers to the conviction that brain oscillations subserve various sensory and cognitive processes, a causal role can only be demonstrated by directly modulating such oscillatory signals. In this review, we highlight several methods to selectively modulate neuronal oscillations, including EEG-neurofeedback, rhythmic sensory stimulation, repetitive transcranial magnetic stimulation (rTMS), and transcranial alternating current stimulation (tACS). In particular, we discuss tACS as the most recent technique to directly modulate oscillatory brain activity. Such studies demonstrating the effectiveness of tACS comprise reports on purely behavioral or purely electrophysiological effects, on combination of behavioral effects with offline EEG measurements or on simultaneous (online) tACS-EEG recordings. Whereas most tACS studies are designed to modulate ongoing rhythmic brain activity at a specific frequency, recent evidence suggests that tACS may also modulate cross-frequency interactions. Taken together, the modulation of neuronal oscillations allows to demonstrate causal links between brain oscillations and cognitive processes and to obtain important insights into human brain function. PMID:25659527

  7. Alpha-1 Antitrypsin Test

    MedlinePlus

    ... measures the level of the protein AAT in blood. Alpha-1 antitrypsin phenotype testing evaluates the amount and type of AAT being produced and compares it to normal patterns. Alpha-1 antitrypsin genotype testing ( DNA testing) can ...

  8. EEG markers of future cognitive performance in the elderly.

    PubMed

    van der Hiele, Karin; Bollen, Eduard L E M; Vein, Alla A; Reijntjes, Robert H A M; Westendorp, Rudi G J; van Buchem, Mark A; Middelkoop, Huub A M; van Dijk, J Gert

    2008-04-01

    This exploratory follow-up study investigated whether EEG parameters can predict future cognitive performance. Forty elderly subjects, ranging from cognitively unimpaired to those with Alzheimer disease underwent EEG registration at baseline and neuropsychological examination at both baseline and follow-up. We assessed relations between EEG measures and future cognitive performance (i.e., global cognition, memory, language, and executive functioning) controlling for age, follow-up time, and baseline cognitive performance. Regression models were constructed to predict performance on the Cambridge Cognitive Examination, a widely used tool within dementia screenings. Baseline EEG measures, i.e., increased theta activity (4-8 Hz) during eyes closed and less alpha reactivity (8-13 Hz) during eyes open and memory activation, indicated lower global cognitive, language (trend significant), and executive performance at follow-up. A regression model combining baseline cognitive and EEG measures provided the best prediction of future Cambridge Cognitive Examination performance (93%). EEG and cognitive measures alone predicted, respectively, 43% and 92% of variance. EEG and cognitive measures combined provided the best prediction of future cognitive performance. Although the "cognition only" model showed similar predictive power, the EEG provided significant additional value. The added value of EEG registration in the diagnostic work-up of dementia should be further assessed in larger samples. PMID:18340274

  9. mRNA expression of HNF-4 isoforms and of HNF-1alpha/HNF-1beta variants and differentiation of human cell lines that mimic highly specialized phenotypes of intestinal epithelium.

    PubMed

    Suaud, L; Joseph, B; Formstecher, P; Laine, B

    1997-06-27

    The mRNA expression of HNF-4 isoforms and the ratio of HNF-1alpha/HNF-1beta variants in cell lines representing highly specialized phenotypes of human intestinal epithelium were studied by RT-PCR. A strong rise in expression of HNF-4 isoforms alpha2, alpha4 and gamma correlates with commitment into highly differentiated enterocyte-like phenotype of Caco-2 cells which best mimic enterocytes, whereas only isoform alpha4 expression is high in the less differentiated HT-29 G- cells. These increased expressions are not encountered in the highly differentiated mucous-secreting HT-29 MTX cells. Differentiation into highly specialized enterocyte-like Caco-2 cells and mucous-secreting HT-29 MTX cells is accompanied by a moderate rise in HNF-1 without change in the ratio of its variants. Our data corroborate those of Spath et al. (Mol. Cell. Biol., 1997, 17, 1913) in hepatoma cells and suggest that HNF-4 isoforms alpha2, alpha4 and gamma play a major role in the differentiation of enterocytes. PMID:9207245

  10. Resting state EEG correlates of memory consolidation.

    PubMed

    Brokaw, Kate; Tishler, Ward; Manceor, Stephanie; Hamilton, Kelly; Gaulden, Andrew; Parr, Elaine; Wamsley, Erin J

    2016-04-01

    Numerous studies demonstrate that post-training sleep benefits human memory. At the same time, emerging data suggest that other resting states may similarly facilitate consolidation. In order to identify the conditions under which non-sleep resting states benefit memory, we conducted an EEG (electroencephalographic) study of verbal memory retention across 15min of eyes-closed rest. Participants (n=26) listened to a short story and then either rested with their eyes closed, or else completed a distractor task for 15min. A delayed recall test was administered immediately following the rest period. We found, first, that quiet rest enhanced memory for the short story. Improved memory was associated with a particular EEG signature of increased slow oscillatory activity (<1Hz), in concert with reduced alpha (8-12Hz) activity. Mindwandering during the retention interval was also associated with improved memory. These observations suggest that a short period of quiet rest can facilitate memory, and that this may occur via an active process of consolidation supported by slow oscillatory EEG activity and characterized by decreased attention to the external environment. Slow oscillatory EEG rhythms are proposed to facilitate memory consolidation during sleep by promoting hippocampal-cortical communication. Our findings suggest that EEG slow oscillations could play a significant role in memory consolidation during other resting states as well. PMID:26802698

  11. EEG Correlates of Self-Referential Processing

    PubMed Central

    Knyazev, Gennady G.

    2013-01-01

    Self-referential processing has been principally investigated using functional magnetic resonance imaging (fMRI). However, understanding of the brain functioning is not possible without careful comparison of the evidence coming from different methodological domains. This paper aims to review electroencephalographic (EEG) studies of self-referential processing and to evaluate how they correspond, complement, or contradict the existing fMRI evidence. There are potentially two approaches to the study of EEG correlates of self-referential processing. Firstly, because simultaneous registration of EEG and fMRI has become possible, the degree of overlap between these two signals in brain regions related to self-referential processing could be determined. Second and more direct approach would be the study of EEG correlates of self-referential processing per se. In this review, I discuss studies, which employed both these approaches and show that in line with fMRI evidence, EEG correlates of self-referential processing are most frequently found in brain regions overlapping with the default network, particularly in the medial prefrontal cortex. In the time domain, the discrimination of self- and others-related information is mostly associated with the P300 ERP component, but sometimes is observed even earlier. In the frequency domain, different frequency oscillations have been shown to contribute to self-referential processing, with spontaneous self-referential mentation being mostly associated with the alpha frequency band. PMID:23761757

  12. EEG correlates of self-referential processing.

    PubMed

    Knyazev, Gennady G

    2013-01-01

    Self-referential processing has been principally investigated using functional magnetic resonance imaging (fMRI). However, understanding of the brain functioning is not possible without careful comparison of the evidence coming from different methodological domains. This paper aims to review electroencephalographic (EEG) studies of self-referential processing and to evaluate how they correspond, complement, or contradict the existing fMRI evidence. There are potentially two approaches to the study of EEG correlates of self-referential processing. Firstly, because simultaneous registration of EEG and fMRI has become possible, the degree of overlap between these two signals in brain regions related to self-referential processing could be determined. Second and more direct approach would be the study of EEG correlates of self-referential processing per se. In this review, I discuss studies, which employed both these approaches and show that in line with fMRI evidence, EEG correlates of self-referential processing are most frequently found in brain regions overlapping with the default network, particularly in the medial prefrontal cortex. In the time domain, the discrimination of self- and others-related information is mostly associated with the P300 ERP component, but sometimes is observed even earlier. In the frequency domain, different frequency oscillations have been shown to contribute to self-referential processing, with spontaneous self-referential mentation being mostly associated with the alpha frequency band. PMID:23761757

  13. Efficiency analysis of voluntary control of human's EEG spectral characteristics.

    PubMed

    Kiroy, Valery N; Aslanyan, Elena V; Lazurenko, Dmitry M; Minyaeva, Nadezhda R; Bakhtin, Oleg M

    2016-03-01

    Spectral power (SP) of EEG alpha and beta-2 frequencies in different cortical areas has been used for neurofeedback training to control a graphic interface in different scenarios. The results show that frequency range and brain cortical areas are associated with high or low efficiency of voluntary control. Overall, EEG phenomena observed in the course of training are largely general changes involving extensive brain areas and frequency bands. Finally, we have demonstrated EEG patterns that dynamically switch with a specific feature in different tasks within one training, after a relatively short period of training. PMID:26912214

  14. Alpha-globin loci in homozygous beta-thalassemia intermedia.

    PubMed

    Triadou, P; Lapoumeroulie, C; Girot, R; Labie, D

    1983-01-01

    Homozygous beta-thalassemia intermediate (TI) differs from thalassemia major (TM) in being less severe clinically. Associated alpha-thalassemia could account for the TI phenotype by reducing the alpha/non-alpha chain imbalance. We have analyzed the alpha loci of 9 TI and 11 TM patients by restriction endonuclease mapping. All the TM and 7 of the TI patients have the normal complement of four alpha-globin genes (alpha alpha/alpha alpha). One TI patient has three alpha-globin genes (alpha alpha/-alpha), and another TI patient has five alpha genes (alpha alpha/alpha alpha alpha). PMID:6305827

  15. Interindividual Differences in Alpha and Theta Power Reflect Memory Performance.

    ERIC Educational Resources Information Center

    Klimesch, W.; Vogt, F.; Doppelmayr, M.

    1999-01-01

    Tested whether tonic EEG power is related to memory performance by analyzing ongoing EEG for 60 subjects in 5 experimental conditions. Subjects with good memory performance had significantly larger upper alpha power, but less theta and lower alpha power. Also discusses findings for subjects good at calculation. (SLD)

  16. Novel active comb-shaped dry electrode for EEG measurement in hairy site.

    PubMed

    Huang, Yan-Jun; Wu, Chung-Yu; Wong, Alice May-Kuen; Lin, Bor-Shyh

    2015-01-01

    Electroencephalography (EEG) is an important biopotential, and has been widely applied in clinical applications. The conventional EEG electrode with conductive gels is usually used for measuring EEG. However, the use of conductive gel also encounters with the issue of drying and hardening. Recently, many dry EEG electrodes based on different conductive materials and techniques were proposed to solve the previous issue. However, measuring EEG in the hairy site is still a difficult challenge. In this study, a novel active comb-shaped dry electrode was proposed to measure EEG in hairy site. Different form other comb-shaped or spike-shaped dry electrodes, it can provide more excellent performance of avoiding the signal attenuation, phase distortion, and the reduction of common mode rejection ratio. Even under walking motion, it can effectively acquire EEG in hairy site. Finally, the experiments for alpha rhythm and steady-state visually evoked potential were also tested to validate the proposed electrode. PMID:25137719

  17. An EEG-Based Fatigue Detection and Mitigation System.

    PubMed

    Huang, Kuan-Chih; Huang, Teng-Yi; Chuang, Chun-Hsiang; King, Jung-Tai; Wang, Yu-Kai; Lin, Chin-Teng; Jung, Tzyy-Ping

    2016-06-01

    Research has indicated that fatigue is a critical factor in cognitive lapses because it negatively affects an individual's internal state, which is then manifested physiologically. This study explores neurophysiological changes, measured by electroencephalogram (EEG), due to fatigue. This study further demonstrates the feasibility of an online closed-loop EEG-based fatigue detection and mitigation system that detects physiological change and can thereby prevent fatigue-related cognitive lapses. More importantly, this work compares the efficacy of fatigue detection and mitigation between the EEG-based and a nonEEG-based random method. Twelve healthy subjects participated in a sustained-attention driving experiment. Each participant's EEG signal was monitored continuously and a warning was delivered in real-time to participants once the EEG signature of fatigue was detected. Study results indicate suppression of the alpha- and theta-power of an occipital component and improved behavioral performance following a warning signal; these findings are in line with those in previous studies. However, study results also showed reduced warning efficacy (i.e. increased response times (RTs) to lane deviations) accompanied by increased alpha-power due to the fluctuation of warnings over time. Furthermore, a comparison of EEG-based and nonEEG-based random approaches clearly demonstrated the necessity of adaptive fatigue-mitigation systems, based on a subject's cognitive level, to deliver warnings. Analytical results clearly demonstrate and validate the efficacy of this online closed-loop EEG-based fatigue detection and mitigation mechanism to identify cognitive lapses that may lead to catastrophic incidents in countless operational environments. PMID:27121994

  18. Identifying periods of drowsy driving using EEG.

    PubMed

    Brown, Timothy; Johnson, Robin; Milavetz, Gary

    2013-01-01

    Drowsy driving is a significant contributor to death and injury crashes on our nation's highways. Predictive neurophysiologic/physiologic solutions to reduce these incidences have been proposed and developed. EEG based metrics were found to be promising in initial studies, but remain controversial in their efficacy, primarily due to failures to develop replication studies within the simulation settings used for development, and real-world validation. This analysis sought to address these short comings by assessing the utility of the B-Alert algorithms, in a replication study of driving and drowsiness. Data were collected on the National Advanced Driving Simulator from 72 volunteer drivers exposed to three types of roadways at three times of day representing different levels of drowsiness. EEG metrics, collected using the B-Alert X10 Wireless Headset were evaluated to determine their utility in future predictive studies. The replication of the B-Alert algorithms was a secondary focus for this analysis, resulting in highly variable start times within each time of day segment, leading to EEG data being confounded by the diurnal variations that occur in the basal EEG signal. Regardless of this limitation, the analysis revealed promising outcomes. The EEG based algorithms for sleep onset, drowsiness, as well as fatigue related power spectral bandwidths (i.e. lateral central, and parietal alpha) varied with time of day of the drives. Interestingly, EEG metrics of cognitive workload were also sensative to the terrain of the drives. The replicaiton of the B-Alert algorithms were a secondary focuse in the study design, Taken together, these data indicate great potential of carefully designed studies to utilize neurophysiologic metrics to identify time of day and task and road conditions that may be at greatest risk during fatigued/drowsy periods. PMID:24406950

  19. Donepezil Impairs Memory in Healthy Older Subjects: Behavioural, EEG and Simultaneous EEG/fMRI Biomarkers

    PubMed Central

    Balsters, Joshua H.; O'Connell, Redmond G.; Martin, Mary P.; Galli, Alessandra; Cassidy, Sarah M.; Kilcullen, Sophia M.; Delmonte, Sonja; Brennan, Sabina; Meaney, Jim F.; Fagan, Andrew J.; Bokde, Arun L. W.; Upton, Neil; Lai, Robert; Laruelle, Marc; Lawlor, Brian; Robertson, Ian H.

    2011-01-01

    Rising life expectancies coupled with an increasing awareness of age-related cognitive decline have led to the unwarranted use of psychopharmaceuticals, including acetylcholinesterase inhibitors (AChEIs), by significant numbers of healthy older individuals. This trend has developed despite very limited data regarding the effectiveness of such drugs on non-clinical groups and recent work indicates that AChEIs can have negative cognitive effects in healthy populations. For the first time, we use a combination of EEG and simultaneous EEG/fMRI to examine the effects of a commonly prescribed AChEI (donepezil) on cognition in healthy older participants. The short- and long-term impact of donepezil was assessed using two double-blind, placebo-controlled trials. In both cases, we utilised cognitive (paired associates learning (CPAL)) and electrophysiological measures (resting EEG power) that have demonstrated high-sensitivity to age-related cognitive decline. Experiment 1 tested the effects of 5 mg/per day dosage on cognitive and EEG markers at 6-hour, 2-week and 4-week follow-ups. In experiment 2, the same markers were further scrutinised using simultaneous EEG/fMRI after a single 5 mg dose. Experiment 1 found significant negative effects of donepezil on CPAL and resting Alpha and Beta band power. Experiment 2 replicated these results and found additional drug-related increases in the Delta band. EEG/fMRI analyses revealed that these oscillatory differences were associated with activity differences in the left hippocampus (Delta), right frontal-parietal network (Alpha), and default-mode network (Beta). We demonstrate the utility of simple cognitive and EEG measures in evaluating drug responses after acute and chronic donepezil administration. The presentation of previously established markers of age-related cognitive decline indicates that AChEIs can impair cognitive function in healthy older individuals. To our knowledge this is the first study to identify the precise

  20. Sleep EEG Fingerprints Reveal Accelerated Thalamocortical Oscillatory Dynamics in Williams Syndrome

    ERIC Educational Resources Information Center

    Bodizs, Robert; Gombos, Ferenc; Kovacs, Ilona

    2012-01-01

    Sleep EEG alterations are emerging features of several developmental disabilities, but detailed quantitative EEG data on the sleep phenotype of patients with Williams syndrome (WS, 7q11.23 microdeletion) is still lacking. Based on laboratory (Study I) and home sleep records (Study II) here we report WS-related features of the patterns of…

  1. [Quantitative pharmaco-EEG study of nootropics].

    PubMed

    Kinoshita, T

    1990-01-01

    A treatment of geriatric disorders is one of the current major problems socially as well as medically. Thus nootropics have become one of the biggest topics in drug developments. Unfortunately, it is still very difficult to assess brain dysfunctions and therapeutic efficacies of these drugs objectively. Giurgea has proposed a new drug category, "nootropic", as those substances which possess an anti-dementia action, yet the general concept remains obscure. The present author expand the concept that those substances which improve the vigilance level to be included. The author has been engaged with computer assisted pharmaco-electroencephalography and research of nootropics for last several years. Based on the own experiences, the author presented the CNS effects of five different substances such as meclofenoxate, amantadine, piracetam, teniloxazine and WEB-1881, which were regarded as nootropics from various reasons. Single dose of each substances was administered in healthy young volunteers, and teniloxazine was given to geriatric patients. EEG changes induced by these substances in normal subjects were an increase of alpha activity, particularly in higher frequency range above 9.5 Hz, and an associated decrease of slow activity and of fast activity, which are different from those of the other psychotropic drugs. Multivariate analysis of variance (MANOVA) of EEG parameters has confirmed that the response of WEB-1881 was most manifest in frontal area. This suggests that WEB-1881 might activate linguistic learning and memory process. In the patient study, the induced EEG changes were an increase of alpha activity associated with a decrease of slow activity, while fast activity did not show any changes. However, the EEG changes in the patient study were quite similar to those of normal volunteer study for the most part. It is relevant to infer the efficacy of nootropics in geriatric patients from acute normal volunteer study. In physiological aging process, alpha

  2. Electroencephalogram (EEG) (For Parents)

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of keeping still while the EEG is done ...

  3. EEG correlates of social interaction at distance

    PubMed Central

    Giroldini, William; Pederzoli, Luciano; Bilucaglia, Marco; Caini, Patrizio; Ferrini, Alessandro; Melloni, Simone; Prati, Elena; Tressoldi, Patrizio

    2016-01-01

    This study investigated EEG correlates of social interaction at distance between twenty-five pairs of participants who were not connected by any traditional channels of communication. Each session involved the application of 128 stimulations separated by intervals of random duration ranging from 4 to 6 seconds. One of the pair received a one-second stimulation from a light signal produced by an arrangement of red LEDs, and a simultaneous 500 Hz sinusoidal audio signal of the same length. The other member of the pair sat in an isolated sound-proof room, such that any sensory interaction between the pair was impossible. An analysis of the Event-Related Potentials associated with sensory stimulation using traditional averaging methods showed a distinct peak at approximately 300 ms, but only in the EEG activity of subjects who were directly stimulated. However, when a new algorithm was applied to the EEG activity based on the correlation between signals from all active electrodes, a weak but robust response was also detected in the EEG activity of the passive member of the pair, particularly within 9 – 10 Hz in the Alpha range. Using the Bootstrap method and the Monte Carlo emulation, this signal was found to be statistically significant. PMID:26966513

  4. EEG correlates of social interaction at distance.

    PubMed

    Giroldini, William; Pederzoli, Luciano; Bilucaglia, Marco; Caini, Patrizio; Ferrini, Alessandro; Melloni, Simone; Prati, Elena; Tressoldi, Patrizio

    2015-01-01

    This study investigated EEG correlates of social interaction at distance between twenty-five pairs of participants who were not connected by any traditional channels of communication. Each session involved the application of 128 stimulations separated by intervals of random duration ranging from 4 to 6 seconds. One of the pair received a one-second stimulation from a light signal produced by an arrangement of red LEDs, and a simultaneous 500 Hz sinusoidal audio signal of the same length. The other member of the pair sat in an isolated sound-proof room, such that any sensory interaction between the pair was impossible. An analysis of the Event-Related Potentials associated with sensory stimulation using traditional averaging methods showed a distinct peak at approximately 300 ms, but only in the EEG activity of subjects who were directly stimulated. However, when a new algorithm was applied to the EEG activity based on the correlation between signals from all active electrodes, a weak but robust response was also detected in the EEG activity of the passive member of the pair, particularly within 9 - 10 Hz in the Alpha range. Using the Bootstrap method and the Monte Carlo emulation, this signal was found to be statistically significant. PMID:26966513

  5. Telemetered EEG in schizophrenia: spectral analysis during abnormal behaviour episodes.

    PubMed Central

    Stevens, J R; Livermore, A

    1982-01-01

    In an attempt to detect electroencephalographic (EEG) changes associated with characteristic clinical signs and symptoms of schizophrenia, power spectra were derived from scalp EEGs of schizophrenic patients recorded by telemetry during free behaviour on their psychiatric wards. Power spectra from EEG epochs coincident with psychomotor blocking, stereotyped automatism or hallucinations were compared with spectra derived during periods of relatively normal behaviour, during performance of specific tasks and spectra from control subjects. Ramp spectra, characterised by a smooth decline in power from lowest to highest frequencies, previously found in conjunction with subcortical spike activity of epilepsy were not found in any control subject, but appeared in spectra from schizophrenic patients during catatonic episodes, hallucinatory periods and visual checking. Schizophrenic patients also had more slow activity and less alpha activity in their EEGs than normal control subjects. Images PMID:7086451

  6. [The EEG and thinking].

    PubMed

    Petsche, H

    1990-12-01

    The on-going EEG contains information on thinking strategies during cognitive and creative tasks and during listening to music. This was demonstrated by a method taking use of the fact that both the amount of local current production and the degree of electric coupling of brain regions is characteristically changed by mental tasks. In groups of volunteers the significant changes of absolute power and coherence caused by different mental tasks are computed and entered into schematic brain maps (EEG probability maps). The results indicate the existence of general brain strategies even in mental activities as specific as those referred to above. Moreover, several relationships between EEG, psychological test scores, degree of special education and intelligence were found. Studies with extreme value validation according to intelligence and creativity test scores yielded significant differences between the groups of the best and the poorest performers during a creative task in the EEG. The EEG thus can be conceived of as deterministic chaos with different degrees of organization according to its information content. In this context, the question arises as to a possible function of the EEG for the optimization of thinking processes. PMID:2127009

  7. EEG Power Spectrum Analysis in Children with ADHD

    PubMed Central

    Kamida, Akira; Shimabayashi, Kenta; Oguri, Masayoshi; Takamori, Toshihiro; Ueda, Naoyuki; Koyanagi, Yuki; Sannomiya, Naoko; Nagira, Haruki; Ikunishi, Saeko; Hattori, Yuiko; Sato, Kengo; Fukuda, Chisako; Hirooka, Yasuaki; Maegaki, Yoshihiro

    2016-01-01

    Background Attention deficit disorder/hyperactivity disorder (ADHD) is a pathological condition that is not fully understood. In this study, we investigated electroencephalographic (EEG) power differences between children with ADHD and healthy control children. Methods EEGs were recorded as part of routine medical care received by 80 children with ADHD aged 4–15 years at the Department of Pediatric Neurology in Tottori University Hospital. Additionally, we recorded in 59 control children aged 4–15 years after obtaining informed consent. Specifically, awake EEG signals were recorded from each child using the international 10–20 system, and we used ten 3-s epochs on the EEG power spectrum to calculate the powers of individual EEG frequency bands. Results The powers of different EEG bands were significantly higher in the frontal brain region of those in the ADHD group compared with the control group. In addition, the power of the beta band in the ADHD group was significantly higher in all brain regions, except for the occipital region, compared with control children. With regard to developmental changes, the power of the alpha band in the occipital region showed an age-dependent decrease in both groups, with slightly lower power in the ADHD group. Additionally, the intergroup difference decreased in children aged 11 years or older. As with the alpha band in the occipital region, the beta band in the frontal region showed an age-dependent decrease in both groups. Unlike the alpha band, the power of the beta band was higher in the ADHD group than in the control group for children of all ages. Conclusion The observed intergroup differences in EEG power may provide insight into the brain function of children with ADHD. PMID:27493489

  8. Phenotypic consequences of deletion of the {gamma}{sub 3}, {alpha}{sub 5}, or {beta}{sub 3} subunit of the type A {gamma}-aminobutyric acid receptor in mice

    SciTech Connect

    Culia, C.T.; Stubbs, L.J.; Montgomery, C.S.; Russell, L.B.; Rinchik, E.M.

    1994-03-29

    Three genes (Gabrg3, Gabra5, and Gabrb3) encoding the {gamma}{sub 3}, {alpha}{sub 5}, and {beta}{sub 3} subunits of the type A {gamma}-aminobutyric acid receptor, respectively, are known to map near the pink-eyed dilution (p) locus in mouse chromosome 7. This region shares homology with a segment of human chromosome 15 that is implicated in Angelman syndrome, an inherited neurobehavioral disorder. By mapping Gabrg3-Gabra5-Gabrb3-telomere. Like Gabrb3, neither the Gabra5 nor Gabrg3 gene is functionally imprinted in adult mouse brain. Mice deleted for all three subunits die at birth with a cleft palate, although there are rare survivors ({approximately} 5%) that do not have a cleft palate but do exhibit a neurological abnormality characterized by tremor, jerky gait, and runtiness. The authors have previously suggested that deficiency of the {beta}{sub 3} subunit may be responsible for the clefting defect. Most notably, however, in this report they describe mice carrying two overlapping, complementing p deletions that fail to express the {gamma}{sub 3} transcript, as well as mice from another line that express neither the {gamma}{sub 3} nor {alpha}{sub 5} transcripts. Surprisingly, mice from both of these lines are phenotypically normal and do not exhibit any of the neurological symptoms characteristic of the rare survivors that are deleted for all three ({gamma}{sub 3}, {alpha}{sub 5}, and {beta}{sub 3}) subunits. These mice therefore provide a whole-organism type A {gamma}-aminobutyric-acid receptor background that is devoid of any receptor subtypes that normally contain the {gamma}{sub 3} and/or {alpha}{sub 5} subunits. The absence of an overt neurological phenotype in mice lacking the {gamma}{sub 3} and/or {alpha}{sub 5} subunits also suggests that mutations in these genes are unlikely to provide useful animal models for Angelman syndrome in humans.

  9. Hypermethods for EEG hyperscanning.

    PubMed

    Babiloni, Fabio; Cincotti, Febo; Mattia, Donatella; Mattiocco, Marco; De Vico Fallani, Fabrizio; Tocci, Andrea; Bianchi, Luigi; Marciani, Maria Grazia; Astolfi, Laura

    2006-01-01

    Until now, in EEG studies the activity of the brain during simple or complex tasks have been recorded in a single subject. Often, during such EEG recordings, subjects interacts with the external devices or the researchers in order to reproduce conditions similar to the those usually occurring in the real-life. However, in order to study the concurrent activity in subjects interacting in cooperation or competition activities, the issue of the simultaneous recording of their brain activity became mandatory. The simultaneous recording of hemodynamic or neuroelectric activity of the brain is called "hyperscanning". We would like present results obtained by EEG hyperscannings performed on a group of subjects engaged in cooperative games. The EEG hyperscannings have been performed with the simultaneous use of high resolution EEG devices on groups of three and four subjects while they were playing cooperative games. The analysis of such data have been conducted with analysis method that taken into account the particular nature of the data simultaneously gathered from different subjects. We called these methods hypermethods. In particular, we estimate the concurrent activity in multiple brains of the group and we depicted the causal connections between regions of different brains (hyperconnectivity). The resulting causality patterns will link certain areas of the brain of a subject to the waveforms obtained from the other brain areas of another subject of the same group. Results obtained in a study of several groups recorded by the hyperscanning reveals causal links between prefrontal areas of the different subjects when they are performing cooperative games in different frequency bands. Hypermethods for hyperscanning will open a different area for the study of neuroscience, in which the activity of multiple brains during social cooperation could be investigated. In such area the importance of EEG will be relevant due to its temporal and spatial resolution now obtainable w

  10. Stability of EEG inter- and intrahemispheric correlation in women.

    PubMed

    Corsi-Cabrera, M; Solís-Ortiz, S; Guevara, M A

    1997-03-01

    EEG correlation and coherence analyses have been used to study functional relationships between cortical regions, and found to vary as a function of physiological conditions, sex hormones and cognitive processes. However, the utility of serial EEG studies is dependent upon the within-subject reliability of repeated EEG recordings. The present study was undertaken to assess the within-subject and within-group stability of EEG correlations in a group of young women (n = 9). EEG was recorded during relaxed wakefulness at F3, F4, C3, C4, P3, P4, O1 and O2 for 11 sessions, during 1 month. Ten artifact free 2-s epochs of EEG from each session were digitally filtered by means of a fast Fourier transform into 6 broad bands, and correlation coefficients between the EEG activity of every pair of derivations and bands were calculated in the time domain. All EEG features were submitted to principal component analysis and the first 5 components did not show significant differences between sessions (ANOVAs) for any band or pair of derivations. Alpha and beta showed higher variability whereas slow bands showed very little variability. The within-subject stability was assessed calculating multiple correlation coefficients between all EEG features of the eleven sessions of each subject: R-values ranged from 0.85 to 0.97. Present results indicate that the pattern of functional relationships between cortical regions during resting wakefulness is a stable characteristic for each woman at least over a 1 month period and that there are no significant group differences over sessions when menstrual phases are randomly distributed between women. PMID:9129580

  11. EEG manifestations of nondual experiences in meditators.

    PubMed

    Berman, Amanda E; Stevens, Larry

    2015-01-01

    The holistic experiential benefits of meditation among a widely ranging population have been well established within the empirical literature. What remain less clear are the underlying mechanisms of the meditative process. A large impediment to this clarity is attributable to the lack of a unified and comprehensive taxonomy, as well as to the absence of clear differentiation within the literature between method of practice and resulting state. The present study discusses and then attempts to identify within our sample a theoretically universal culminating meditative state known as Nondual Awareness, which is differentiated from the method or practice state. Participants completed an in-lab meditation, during which neurological patterns were analyzed using electroencephalography (EEG). Analyses indicated significantly higher EEG power among slower wave frequencies (delta, theta, alpha) during the reported nondual events. These events appear neurologically distinct from meditation sessions as a whole, which interestingly demonstrated significant elevation within the gamma range. PMID:25460236

  12. Rescue of type I collagen-deficient phenotype by retroviral-vector-mediated transfer of human pro alpha 1(I) collagen gene into Mov-13 cells.

    PubMed Central

    Stacey, A; Mulligan, R; Jaenisch, R

    1987-01-01

    A full-length cDNA clone corresponding to the human pro alpha 1(I) collagen gene was isolated and inserted into a retrovirus vector. Cell lines were obtained which produced recombinant viruses transducing the collagen cDNA (HUC virus). To test whether the transduced cDNA was functional, Mov-13 mouse cells were infected with the virus. These cells do not produce any type I collagen due to an insertional mutation of the pro alpha 1(I) gene which blocks transcription. While normal amounts of pro alpha 2(I) RNA were synthesized, no alpha 2(I) collagen chains were detectable in the mutant Mov-13 cells. Infection with HUC virus, however, resulted in the production of stable type I collagen, which was secreted into the medium. Analysis of pepsin-resistant proteins indicated that interspecies heterotrimers consisting of human alpha 1(I) and mouse alpha 2(I) collagen chains were secreted by the infected Mov-13 cells. Our results show that pro alpha (I) collagen chains from species as distant as human and mouse can associate to form stable type I collagen. The availability of a retrovirus vector transducing a functional pro alpha 1(I) collagen gene combined with the Mov-13 mutant system should enable us to study the effect of specific mutations on the synthesis, assembly, and function of type I collagen, not only in tissue culture but also in the animal. Images PMID:3599181

  13. Electromyographic Activity in the EEG in Alzheimer's Disease: Noise or Signal?

    PubMed Central

    van der Hiele, Karin; Reijntjes, Robert H. A. M.; Vein, Alla A.; Westendorp, Rudi G. J.; van Buchem, Mark A.; Bollen, Eduard L. E. M.; Middelkoop, Huub A. M.; van Dijk, J. Gert

    2011-01-01

    Many efforts have been directed at negating the influence of electromyographic (EMG) activity on the EEG, especially in elderly demented patients. We wondered whether these “artifacts” might reflect cognitive and behavioural aspects of dementia. In this pilot study, 11 patients with probable Alzheimer's disease (AD), 13 with amnestic mild cognitive impairment (MCI) and 13 controls underwent EEG registration. As EMG measures, we used frontal and temporal 50–70 Hz activity. We found that the EEGs of AD patients displayed more theta activity, less alpha reactivity, and more frontal EMG than controls. Interestingly, increased EMG activity indicated more cognitive impairment and more depressive complaints. EEG variables on the whole distinguished better between groups than EMG variables, but an EMG variable was best for the distinction between MCI and controls. Our results suggest that EMG activity in the EEG could be more than noise; it differs systematically between groups and may reflect different cerebral functions than the EEG. PMID:21559240

  14. Electromyographic activity in the EEG in Alzheimer's disease: noise or signal?

    PubMed

    van der Hiele, Karin; Reijntjes, Robert H A M; Vein, Alla A; Westendorp, Rudi G J; van Buchem, Mark A; Bollen, Eduard L E M; Middelkoop, Huub A M; van Dijk, J Gert

    2011-01-01

    Many efforts have been directed at negating the influence of electromyographic (EMG) activity on the EEG, especially in elderly demented patients. We wondered whether these "artifacts" might reflect cognitive and behavioural aspects of dementia. In this pilot study, 11 patients with probable Alzheimer's disease (AD), 13 with amnestic mild cognitive impairment (MCI) and 13 controls underwent EEG registration. As EMG measures, we used frontal and temporal 50-70 Hz activity. We found that the EEGs of AD patients displayed more theta activity, less alpha reactivity, and more frontal EMG than controls. Interestingly, increased EMG activity indicated more cognitive impairment and more depressive complaints. EEG variables on the whole distinguished better between groups than EMG variables, but an EMG variable was best for the distinction between MCI and controls. Our results suggest that EMG activity in the EEG could be more than noise; it differs systematically between groups and may reflect different cerebral functions than the EEG. PMID:21559240

  15. [Age Effect on Relationship Between Intelligence and EEG Characteristics].

    PubMed

    Belousova, L V; Razumnikova, O M; Volf, N V

    2015-01-01

    Age effect on EEG correlates of psychometrically estimated intelligence (IQ) in the younger (N = 132, age mean = 21.8 ± 3.1) and elder groups (N = 84, age mean = 64.1 ± 6.6) was studied. Regression analysis of individual alpha peak frequency's meanings, total power of biopotentials in eight frequency ranges indicated that a decrease of IQ correlates with age increase, or with decrease of individual alpha peak frequency with positive contribution of the alpha3 power and negative--of the beta1. High meaning of the alpha3 power and low meaning of the beta1 are the predictors of high intelligence in the younger group. High intelligence in the elder group is accompanied by a trend to increase of the individual alpha peak frequency and to decrease of the theta/beta1 power ration together with significant decrease of the alpha3/alpha2 power ratio. PMID:26841657

  16. Resting state cortical rhythms in athletes: a high-resolution EEG study.

    PubMed

    Babiloni, Claudio; Marzano, Nicola; Iacoboni, Marco; Infarinato, Francesco; Aschieri, Pierluigi; Buffo, Paola; Cibelli, Giuseppe; Soricelli, Andrea; Eusebi, Fabrizio; Del Percio, Claudio

    2010-01-15

    The present electroencephalographic (EEG) study tested the working hypothesis that the amplitude of resting state cortical EEG rhythms (especially alpha, 8-12 Hz) was higher in elite athletes compared with amateur athletes and non-athletes, as a reflection of the efficiency of underlying back-ground neural synchronization mechanisms. Eyes closed resting state EEG data were recorded in 16 elite karate athletes, 20 amateur karate athletes, and 25 non-athletes. The EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Statistical results showed that the amplitude of parietal and occipital alpha 1 sources was significantly higher in the elite karate athletes than in the non-athletes and karate amateur athletes. Similar results were observed in parietal and occipital delta sources as well as in occipital theta sources. Finally, a control confirmatory experiment showed that the amplitude of parietal and occipital delta and alpha 1 sources was stronger in 8 elite rhythmic gymnasts compared with 14 non-athletes. These results supported the hypothesis that cortical neural synchronization at the basis of eyes-closed resting state EEG rhythms is enhanced in elite athletes than in control subjects. PMID:19879337

  17. T-cell alpha beta + and gamma delta + deficient mice display abnormal but distinct phenotypes toward a natural, widespread infection of the intestinal epithelium.

    PubMed Central

    Roberts, S J; Smith, A L; West, A B; Wen, L; Findly, R C; Owen, M J; Hayday, A C

    1996-01-01

    Vertebrate immune systems contain T cells bearing either alpha beta or gamma delta T-cell antigen receptors (TCRs). alpha beta T cells perform all well-characterized T-cell effector functions, while the biological functions of gamma delta + cells remain unclear. Of particular interest is the role of gamma delta + cells during epithelial infections, since gamma delta + cells are commonly abundant within epithelia. Eimeria spp. are intracellular protozoa that infect epithelia of most vertebrates, causing coccidiosis. This study shows that in response to Eimeria vermiformis, mice lacking alpha beta T cells display defects in protective immunity, while mice lacking gamma delta + cells display exaggerated intestinal damage, apparently due to a failure to regulate the consequences of the alpha beta T cell response. An immuno-downregulatory role during infection, and during autoimmune disease, may be a general one for gamma delta + cells. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:8876213

  18. Atypical Alpha Asymmetry in Adults with ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

    2009-01-01

    Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha…

  19. Motion and ballistocardiogram artifact removal for interleaved recording of EEG and EPs during MRI.

    PubMed

    Bonmassar, Giorgio; Purdon, Patrick L; Jääskeläinen, Iiro P; Chiappa, Keith; Solo, Victor; Brown, Emery N; Belliveau, John W

    2002-08-01

    Artifacts generated by motion (e.g., ballistocardiac) of the head inside a high magnetic field corrupt recordings of EEG and EPs. This paper introduces a method for motion artifact cancellation. This method is based on adaptive filtering and takes advantage of piezoelectric motion sensor information to estimate the motion artifact noise. This filter estimates the mapping between motion sensor and EEG space, subtracting the motion-related noise from the raw EEG signal. Due to possible subject motion and changes in electrode impedance, a time-varying mapping of the motion versus EEG is required. We show that this filter is capable of removing both ballistocardiogram and gross motion artifacts, restoring EEG alpha waves (8-13 Hz), and visual evoked potentials (VEPs). This adaptive filter outperforms the simple band-pass filter for alpha detection because it is also capable of reducing noise within the frequency band of interest. In addition, this filter also removes the transient responses normally visible in the EEG window after echo planar image acquisition, observed during interleaved EEG/fMRI recordings. Our adaptive filter approach can be implemented in real-time to allow for continuous monitoring of EEG and fMRI during clinical and cognitive studies. PMID:12202099

  20. EEG data compression techniques.

    PubMed

    Antoniol, G; Tonella, P

    1997-02-01

    In this paper, electroencephalograph (EEG) and Holter EEG data compression techniques which allow perfect reconstruction of the recorded waveform from the compressed one are presented and discussed. Data compression permits one to achieve significant reduction in the space required to store signals and in transmission time. The Huffman coding technique in conjunction with derivative computation reaches high compression ratios (on average 49% on Holter and 58% on EEG signals) with low computational complexity. By exploiting this result a simple and fast encoder/decoder scheme capable of real-time performance on a PC was implemented. This simple technique is compared with other predictive transformations, vector quantization, discrete cosine transform (DCT), and repetition count compression methods. Finally, it is shown that the adoption of a collapsed Huffman tree for the encoding/decoding operations allows one to choose the maximum codeword length without significantly affecting the compression ratio. Therefore, low cost commercial microcontrollers and storage devices can be effectively used to store long Holter EEG's in a compressed format. PMID:9214790

  1. Flexible electroencephalogram (EEG) headband

    NASA Technical Reports Server (NTRS)

    Raggio, L. J.

    1973-01-01

    Headband incorporates sensors which are embedded in sponges and are exposed only on surface that touches skin. Electrode sponge system is continually fed electrolyte through forced feed vacuum system. Headband may be used for EEG testing in hospitals, clinical laboratories, rest homes, and law enforcement agencies.

  2. Association of EEG, MRI, and regional blood flow biomarkers is predictive of prodromal Alzheimer’s disease

    PubMed Central

    Moretti, Davide Vito

    2015-01-01

    Background Thinning in the temporoparietal cortex, hippocampal atrophy, and a lower regional blood perfusion is connected with prodromal stage of Alzheimer’s disease (AD). Of note, an increase of electroencephalography (EEG) upper/low alpha frequency power ratio has also been associated with these major landmarks of prodromal AD. Methods Clinical and neuropsychological assessment, EEG recording, and high-resolution three-dimensional magnetic resonance imaging were done in 74 grown up subjects with mild cognitive impairment. This information was gathered and has been assessed 3 years postliminary. EEG recording and perfusion single-photon emission computed tomography assessment was done in 27 subjects. Alpha3/alpha2 frequency power ratio, including cortical thickness, was figured for every subject. Contrasts in cortical thickness among the groups were assessed. Pearson’s r relationship coefficient was utilized to evaluate the quality of the relationship between cortical thinning, brain perfusion, and EEG markers. Results The higher alpha3/alpha2 frequency power ratio group corresponded with more prominent cortical decay and a lower perfusional rate in the temporoparietal cortex. In a subsequent meetup after 3 years, these patients had AD. Conclusion High EEG upper/low alpha power ratio was connected with cortical diminishing and lower perfusion in the temporoparietal brain area. The increase in EEG upper/low alpha frequency power ratio could be helpful in recognizing people in danger of conversion to AD dementia and this may be quality information in connection with clinical assessment. PMID:26604762

  3. Psychophysical and EEG responses to repeated experimental muscle pain in humans: pain intensity encodes EEG activity.

    PubMed

    Chang, Peng-Fei; Arendt-Nielsen, Lars; Graven-Nielsen, Thomas; Chen, Andrew C N

    2003-02-15

    Clinical pain is often characterized by repetitive and persistent occurrence in deep structures, but few studies investigated repetitive tonic pain in humans. To determine cerebral responses to repetitive tonic pain, psychophysical responses, and electroencephalographic (EEG) activation to five trials of repeated tonic muscle pain induced by hypertonic saline were examined and analyzed in 13 male subjects. The study was composed of two experimental sessions performed in separate days. Five sequential injections of hypertonic saline (5.8%) were used to induce repeated muscle pain in the left forearm, and five sequential injections of isotonic saline (0.9%) acted as control. Visual analogue scales (VAS) for pain intensity and 32-channels EEG activities were recorded simultaneously. Five trials of relatively stable muscle pain were induced by intramuscular injections of hypertonic saline, but no evident pain was induced by the injections of isotonic saline. Significant decreases in alpha-1 and -2 activities in posterior part of the head were found during repeated muscle pain in comparison with non-pain. In comparison with baseline, alpha-1 and -2 activities reduced significantly during the first two trials, and gradually resumed in the following three trials of muscle pain. However, beta-2 activity increased consistently throughout the five trials of muscle pain compared to baseline. Alpha-1 activity was negatively, but beta-2 activity was positively correlated to the pain intensity and pain area on the skin. Throughout five injections, the reduction of alpha-1 activity was contrary to the changes of pain intensity. These results indicates that pain-related EEG activities were encoded by the pain intensity. The thalamo-cortical system and descending inhibitory neuronal networks may be involved in the regulation of pain intensity. PMID:12576151

  4. Exon-intron structure of the human neuronal nicotinic acetylcholine receptor {alpha}4 subunit (CHRNA4)

    SciTech Connect

    Steinlein, O.; Weiland, S.; Stoodt, J.; Propping, P.

    1996-03-01

    The human neuronal nicotinic acetylcholine receptor {alpha}4 subunit gene (CHRNA4) is located in the candidate region for three different phenotypes: benign familial neonatal convulsions, autosomal dominant nocturnal frontal lobe epilepsy, and low-voltage EEG. Recently, a missense mutation in transmembrane domain 2 of CHRNA4 was found to be associated with autosomal dominant nocturnal frontal lobe epilepsy in one extended pedigree. We have determined the genomic organization of CHRNA4, which consists of six exons distributed over approximately 17 kb of genomic DNA. The nucleotide sequence obtained from the genomic regions adjacent to the exon boundaries enabled us to develop a set of primer pairs for PCR amplification of the complete coding region. The sequence analysis provides the basis for a comprehensive mutation screening of CHRNA4 in the above-mentioned phenotypes and possibly in other types of idopathic epilepsies. 29 refs., 3 figs., 1 tab.

  5. The Default Mode Network and EEG Regional Spectral Power: A Simultaneous fMRI-EEG Study

    PubMed Central

    Werner, Cornelius J.; Hitz, Konrad; Boers, Frank; Kawohl, Wolfram; Shah, N. Jon

    2014-01-01

    Electroencephalography (EEG) frequencies have been linked to specific functions as an “electrophysiological signature” of a function. A combination of oscillatory rhythms has also been described for specific functions, with or without predominance of one specific frequency-band. In a simultaneous fMRI-EEG study at 3 T we studied the relationship between the default mode network (DMN) and the power of EEG frequency bands. As a methodological approach, we applied Multivariate Exploratory Linear Optimized Decomposition into Independent Components (MELODIC) and dual regression analysis for fMRI resting state data. EEG power for the alpha, beta, delta and theta-bands were extracted from the structures forming the DMN in a region-of-interest approach by applying Low Resolution Electromagnetic Tomography (LORETA). A strong link between the spontaneous BOLD response of the left parahippocampal gyrus and the delta-band extracted from the anterior cingulate cortex was found. A positive correlation between the beta-1 frequency power extracted from the posterior cingulate cortex (PCC) and the spontaneous BOLD response of the right supplementary motor cortex was also established. The beta-2 frequency power extracted from the PCC and the precuneus showed a positive correlation with the BOLD response of the right frontal cortex. Our results support the notion of beta-band activity governing the “status quo” in cognitive and motor setup. The highly significant correlation found between the delta power within the DMN and the parahippocampal gyrus is in line with the association of delta frequencies with memory processes. We assumed “ongoing activity” during “resting state” in bringing events from the past to the mind, in which the parahippocampal gyrus is a relevant structure. Our data demonstrate that spontaneous BOLD fluctuations within the DMN are associated with different EEG-bands and strengthen the conclusion that this network is characterized by a specific

  6. k-Nearest neighbour local linear prediction of scalp EEG activity during intermittent photic stimulation.

    PubMed

    Erla, Silvia; Faes, Luca; Tranquillini, Enzo; Orrico, Daniele; Nollo, Giandomenico

    2011-05-01

    The characterization of the EEG response to photic stimulation (PS) is an important issue with significant clinical relevance. This study aims to quantify and map the complexity of the EEG during PS, where complexity is measured as the degree of unpredictability resulting from local linear prediction. EEG activity was recorded with eyes closed (EC) and eyes open (EO) during resting and PS at 5, 10, and 15 Hz in a group of 30 healthy subjects and in a case-report of a patient suffering from cerebral ischemia. The mean squared prediction error (MSPE) resulting from k-nearest neighbour local linear prediction was calculated in each condition as an index of EEG unpredictability. The linear or nonlinear nature of the system underlying EEG activity was evaluated quantifying MSPE as a function of the neighbourhood size during local linear prediction, and by surrogate data analysis as well. Unpredictability maps were obtained for each subject interpolating MSPE values over a schematic head representation. Results on healthy subjects evidenced: (i) the prevalence of linear mechanisms in the generation of EEG dynamics, (ii) the lower predictability of EO EEG, (iii) the desynchronization of oscillatory mechanisms during PS leading to increased EEG complexity, (iv) the entrainment of alpha rhythm during EC obtained by 10 Hz PS, and (v) differences of EEG predictability among different scalp regions. Ischemic patient showed different MSPE values in healthy and damaged regions. The EEG predictability decreased moving from the early acute stage to a stage of partial recovery. These results suggest that nonlinear prediction can be a useful tool to characterize EEG dynamics during PS protocols, and may consequently constitute a complement of quantitative EEG analysis in clinical applications. PMID:21216649

  7. Electroencephalograph (EEG) study of brain bistable illusion

    NASA Astrophysics Data System (ADS)

    Meng, Qinglei; Hong, Elliot; Choa, Fow-Sen

    2015-05-01

    Bistable illusion reflects two different kinds of interpretations for a single image, which is currently known as a competition between two groups of antagonism of neurons. Recent research indicates that these two groups of antagonism of neurons express different comprehension, while one group is emitting a pulse, the other group will be restrained. On the other hand, when this inhibition mechanism becomes weaker, the other antagonism neurons group will take over the interpretation. Since attention plays key roles controlling cognition, is highly interesting to find the location and frequency band used by brain (with either top-down or bottom-up control) to reach deterministic visual perceptions. In our study, we used a 16-channel EEG system to record brain signals from subjects while conducting bistable illusion testing. An extra channel of the EEG system was used for temporal marking. The moment when subjects reach a perception switch, they click the channel and mark the time. The recorded data were presented in form of brain electrical activity map (BEAM) with different frequency bands for analysis. It was found that the visual cortex in the on the right side between parietal and occipital areas was controlling the switching of perception. In the periods with stable perception, we can constantly observe all the delta, theta, alpha and beta waves. While the period perception is switching, almost all theta, alpha, and beta waves were suppressed by delta waves. This result suggests that delta wave may control the processing of perception switching.

  8. EEG analyses with SOBI.

    SciTech Connect

    Glickman, Matthew R.; Tang, Akaysha

    2009-02-01

    The motivating vision behind Sandia's MENTOR/PAL LDRD project has been that of systems which use real-time psychophysiological data to support and enhance human performance, both individually and of groups. Relevant and significant psychophysiological data being a necessary prerequisite to such systems, this LDRD has focused on identifying and refining such signals. The project has focused in particular on EEG (electroencephalogram) data as a promising candidate signal because it (potentially) provides a broad window on brain activity with relatively low cost and logistical constraints. We report here on two analyses performed on EEG data collected in this project using the SOBI (Second Order Blind Identification) algorithm to identify two independent sources of brain activity: one in the frontal lobe and one in the occipital. The first study looks at directional influences between the two components, while the second study looks at inferring gender based upon the frontal component.

  9. [Changes in the EEG frequency spectrum in various phases of mental stress].

    PubMed

    Mecklinger, A; Bösel, R

    1989-01-01

    To obtain evidence about the relationship between spontaneous EEG activity and mental activity, an experiment was designed and executed with EEG recordings during a concept-learning task. We varied task performance (self-paced vs. machine-paced) and distinguished different stages of information processing during task performance. Using factor analysis calculated on all spectral coefficients, we found two orthogonal variables in the clinical alpha band. Alpha 2 power (10.5-12 Hz) seems to reflect the overall processing demands imposed on the individuals. Furthermore, there are different EEG frequency patterns during perceptual-central- compared with response-related processing as well as during processing of positive vs. negative feedback. The results suggest using (1) conservative procedures in hypothesis testing and (2) procedures to reduce between subject variability (a posteriori defined frequency variables, relative power values, scaling of reaction values) in further studies relating EEG activity to mental activity during task performance. PMID:2588701

  10. Y-position cysteine substitution in type I collagen (alpha1(I) R888C/p.R1066C) is associated with osteogenesis imperfecta/Ehlers-Danlos syndrome phenotype.

    PubMed

    Cabral, Wayne A; Makareeva, Elena; Letocha, Anne D; Scribanu, Nina; Fertala, Andrzej; Steplewski, Andrzej; Keene, Douglas R; Persikov, Anton V; Leikin, Sergey; Marini, Joan C

    2007-04-01

    The most common mutations in type I collagen causing types II-IV osteogenesis imperfecta (OI) result in substitution for glycine in a Gly-Xaa-Yaa triplet by another amino acid. We delineated a Y-position substitution in a small pedigree with a combined OI/Ehlers-Danlos Syndrome (EDS) phenotype, characterized by moderately decreased DEXA z-score (-1.3 to -2.6), long bone fractures, and large-joint hyperextensibility. Affected individuals have an alpha1(I)R888C (p.R1066C) substitution in one COL1A1 allele. Polyacrylamide gel electrophoresis (PAGE) of [(3)H]-proline labeled steady-state collagen reveals slight overmodification of the alpha1(I) monomer band, much less than expected for a substitution of a neighboring glycine residue, and a faint alpha1(I) dimer. Dimers form in about 10% of proband type I collagen. Dimer formation is inefficient compared to a possible 25%, probably because the SH-side chains have less proximity in this Y-position than when substituting for a glycine. Theoretical stability calculations, differential scanning calorimetry (DSC) thermograms, and thermal denaturation curves showed only weak local destabilization from the Y-position substitution in one or two chains of a collagen helix, but greater destabilization is seen in collagen containing dimers. Y-position collagen dimers cause kinking of the helix, resulting in a register shift that is propagated the full length of the helix and causes resistance to procollagen processing by N-proteinase. Collagen containing the Y-position substitution is incorporated into matrix deposited in culture, including immaturely and maturely cross-linked fractions. In vivo, proband dermal fibrils have decreased density and increased diameter compared to controls, with occasional aggregate formation. This report on Y-position substitutions in type I collagen extends the range of phenotypes caused by nonglycine substitutions and shows that, similar to X- and Y-position substitutions in types II and III

  11. EEG of Chronic Marijuana Users during Abstinence: Relationship to Years of Marijuana Use, Cerebral Blood Flow and Thyroid Function

    PubMed Central

    Herning, Ronald I.; Better, Warren; Cadet, Jean L.

    2008-01-01

    Objective Marijuana abuse is associated with neurological changes including increases in frontal EEG alpha during abstinence. Research is needed to assess to what extent these EEG patterns are indicative of cerebral perfusion deficits. Methods We recorded the resting eyes closed EEG of 75 abstinent marijuana users and 33 control subjects. Fifty-six marijuana users used marijuana for less than eight years and 19 used for eight years or more. The EEG evaluation occurred within 72 hours of admission to an inpatient unit. Fifty-nine marijuana users remained abstinent for a month and were tested twice. Supplemental psychological and physiological data were also collected. Results Log alpha2 and beta2 power at posterior sites were significantly lower for the marijuana abusers that used eight years or more than the other marijuana abusers and the control subjects. These EEG changes continued for the month of abstinence. The marijuana users who used marijuana for more than eight years, also, had lower heart rates and thyroid function (T4) compared to the other marijuana users and the control subjects. Conclusions Chronic marijuana use was also associated with reduced EEG power in alpha and beta bands at posterior sites. These reductions in EEG power appear to be related to cerebral perfusion deficits and/or thyroid function in marijuana abusers. Significance Our results suggest EEG, cerebral blood flow velocity, cardiovascular and thyroid function alterations in marijuana abuser with an extended period of use. These alterations reflect under arousal in these systems. PMID:18065267

  12. Tobacco Smoking and the Resting Maternal Brain: A Preliminary Study of Frontal EEG

    PubMed Central

    Wilbanks, Haley E.; Von Mohr, Mariana; Potenza, Marc N.; Mayes, Linda C.; Rutherford, Helena J.V.

    2016-01-01

    Tobacco smoking has been attributed to a wide range of detrimental health consequences for both women and their children. In addition to its known physical health effects, smoking may also impact maternal neural responses and subsequent caregiving behavior. To begin investigating this issue, we employed electroencephalography (EEG) to examine resting neural oscillations of tobacco-smoking mothers (n = 35) and non-smoking mothers (n = 35). We examined seven EEG frequency bands recorded from frontal electrode sites (delta, theta, alpha, alpha1, alpha2, beta, and gamma). While no between-group differences were present in high-frequency bands (alpha2, beta, gamma), smokers showed greater spectral power in low-frequency bands (delta, theta, alpha, alpha1) compared to non-smokers. This increased power in low-frequency bands of tobacco-smoking mothers is consistent with a less aroused state and may be one mechanism through which smoking might affect the maternal brain and caregiving behavior. PMID:27354838

  13. Brain Oscillations in Sport: Toward EEG Biomarkers of Performance

    PubMed Central

    Cheron, Guy; Petit, Géraldine; Cheron, Julian; Leroy, Axelle; Cebolla, Anita; Cevallos, Carlos; Petieau, Mathieu; Hoellinger, Thomas; Zarka, David; Clarinval, Anne-Marie; Dan, Bernard

    2016-01-01

    Brain dynamics is at the basis of top performance accomplishment in sports. The search for neural biomarkers of performance remains a challenge in movement science and sport psychology. The non-invasive nature of high-density electroencephalography (EEG) recording has made it a most promising avenue for providing quantitative feedback to practitioners and coaches. Here, we review the current relevance of the main types of EEG oscillations in order to trace a perspective for future practical applications of EEG and event-related potentials (ERP) in sport. In this context, the hypotheses of unified brain rhythms and continuity between wake and sleep states should provide a functional template for EEG biomarkers in sport. The oscillations in the thalamo-cortical and hippocampal circuitry including the physiology of the place cells and the grid cells provide a frame of reference for the analysis of delta, theta, beta, alpha (incl.mu), and gamma oscillations recorded in the space field of human performance. Based on recent neuronal models facilitating the distinction between the different dynamic regimes (selective gating and binding) in these different oscillations we suggest an integrated approach articulating together the classical biomechanical factors (3D movements and EMG) and the high-density EEG and ERP signals to allow finer mathematical analysis to optimize sport performance, such as microstates, coherency/directionality analysis and neural generators. PMID:26955362

  14. Spectral EEG Features of a Short Psycho-physiological Relaxation

    NASA Astrophysics Data System (ADS)

    Teplan, Michal; Krakovská, Anna; Špajdel, Marián

    2014-08-01

    Short-lasting psycho-physiological relaxation was investigated through an analysis of its bipolar electroencephalographic (EEG) characteristics. In 8 subjects, 6-channel EEG data of 3-minute duration were recorded during 88 relaxation sessions. Time course of spectral EEG features was examined. Alpha powers were decreasing during resting conditions of 3-minute sessions in lying position with eyes closed. This was followed by a decrease of total power in centro-parietal cortex regions and an increase of beta power in fronto-central areas. Represented by EEG coherences the interhemispheric communication between the parieto-occipital regions was enhanced within a frequency range of 2-10 Hz. In order to discern between higher and lower levels of relaxation distinguished according to self-rated satisfaction, EEG features were assessed and discriminating parameters were identified. Successful relaxation was determined mainly by the presence of decreased delta-1 power across the cortex. Potential applications for these findings include the clinical, pharmacological, and stress management fields.

  15. Diagnostic accuracy of microEEG: a miniature, wireless EEG device.

    PubMed

    Grant, Arthur C; Abdel-Baki, Samah G; Omurtag, Ahmet; Sinert, Richard; Chari, Geetha; Malhotra, Schweta; Weedon, Jeremy; Fenton, Andre A; Zehtabchi, Shahriar

    2014-05-01

    Measuring the diagnostic accuracy (DA) of an EEG device is unconventional and complicated by imperfect interrater reliability. We sought to compare the DA of a miniature, wireless, battery-powered EEG device ("microEEG") to a reference EEG machine in emergency department (ED) patients with altered mental status (AMS). Two hundred twenty-five ED patients with AMS underwent 3 EEGs. Two EEGs, EEG1 (Nicolet Monitor, "reference") and EEG2 (microEEG) were recorded simultaneously with EEG cup electrodes using a signal splitter. The remaining study, EEG3, was recorded with microEEG using an electrode cap immediately before or after EEG1/EEG2. The official EEG1 interpretation was considered the gold standard (EEG1-GS). EEG1, 2, and 3 were de-identified and blindly interpreted by two independent readers. A generalized mixed linear model was used to estimate the sensitivity and specificity of these interpretations relative to EEG1-GS and to compute a diagnostic odds ratio (DOR). Seventy-nine percent of EEG1-GS were abnormal. Neither the DOR nor the κf representing interrater reliabilities differed significantly between EEG1, EEG2, and EEG3. The mean setup time was 27 min for EEG1/EEG2 and 12 min for EEG3. The mean electrode impedance of EEG3 recordings was 12.6 kΩ (SD: 31.9 kΩ). The diagnostic accuracy of microEEG was comparable to that of the reference system and was not reduced when the EEG electrodes had high and unbalanced impedances. A common practice with many scientific instruments, measurement of EEG device DA provides an independent and quantitative assessment of device performance. PMID:24727466

  16. Studying the default mode and its mindfulness-induced changes using EEG functional connectivity

    PubMed Central

    Glicksohn, Joseph; Goldstein, Abraham

    2014-01-01

    The default mode network (DMN) has been largely studied by imaging, but not yet by neurodynamics, using electroencephalography (EEG) functional connectivity (FC). mindfulness meditation (MM), a receptive, non-elaborative training is theorized to lower DMN activity. We explored: (i) the usefulness of EEG-FC for investigating the DMN and (ii) the MM-induced EEG-FC effects. To this end, three MM groups were compared with controls, employing EEG-FC (–MPC, mean phase coherence). Our results show that: (i) DMN activity was identified as reduced overall inter-hemispheric gamma MPC during the transition from resting state to a time production task and (ii) MM-induced a state increase in alpha MPC as well as a trait decrease in EEG-FC. The MM-induced EEG-FC decrease was irrespective of expertise or band. Specifically, there was a relative reduction in right theta MPC, and left alpha and gamma MPC. The left gamma MPC was negatively correlated with MM expertise, possibly related to lower internal verbalization. The trait lower gamma MPC supports the notion of MM-induced reduction in DMN activity, related with self-reference and mind-wandering. This report emphasizes the possibility of studying the DMN using EEG-FC as well as the importance of studying meditation in relation to it. PMID:24194576

  17. EEG Topographic Mapping of Visual and Kinesthetic Imagery in Swimmers.

    PubMed

    Wilson, V E; Dikman, Z; Bird, E I; Williams, J M; Harmison, R; Shaw-Thornton, L; Schwartz, G E

    2016-03-01

    This study investigated differences in QEEG measures between kinesthetic and visual imagery of a 100-m swim in 36 elite competitive swimmers. Background information and post-trial checks controlled for the modality of imagery, swimming skill level, preferred imagery style, intensity of image and task equality. Measures of EEG relative magnitude in theta, low (7-9 Hz) and high alpha (8-10 Hz), and low and high beta were taken from 19 scalp sites during baseline, visual, and kinesthetic imagery. QEEG magnitudes in the low alpha band during the visual and kinesthetic conditions were attenuated from baseline in low band alpha but no changes were seen in any other bands. Swimmers produced more low alpha EEG magnitude during visual versus kinesthetic imagery. This was interpreted as the swimmers having a greater efficiency at producing visual imagery. Participants who reported a strong intensity versus a weaker feeling of the image (kinesthetic) had less low alpha magnitude, i.e., there was use of more cortical resources, but not for the visual condition. These data suggest that low band (7-9 Hz) alpha distinguishes imagery modalities from baseline, visual imagery requires less cortical resources than kinesthetic imagery, and that intense feelings of swimming requires more brain activity than less intense feelings. PMID:26420001

  18. Classification of Single Normal and Alzheimer's Disease Individuals from Cortical Sources of Resting State EEG Rhythms

    PubMed Central

    Babiloni, Claudio; Triggiani, Antonio I.; Lizio, Roberta; Cordone, Susanna; Tattoli, Giacomo; Bevilacqua, Vitoantonio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Millán-Calenti, José C.; Buján, Ana; Tortelli, Rosanna; Cardinali, Valentina; Barulli, Maria Rosaria; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Frisoni, Giovanni B.; del Percio, Claudio

    2016-01-01

    Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG) rhythms in groups of Alzheimer's disease (AD) compared to healthy elderly (Nold) subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA) estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), beta 2 (20–30 Hz), and gamma (30–40 Hz) were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC) higher than 0.7 as a threshold for a moderate classification rate (i.e., 70%). Results showed that the following EEG markers overcame this threshold: (i) central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii) central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii) frontal theta/alpha 1 current density; (iv) occipital delta/alpha 1 inter-hemispherical connectivity; (v) occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi) parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%). These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%. PMID:26941594

  19. Classification of Single Normal and Alzheimer's Disease Individuals from Cortical Sources of Resting State EEG Rhythms.

    PubMed

    Babiloni, Claudio; Triggiani, Antonio I; Lizio, Roberta; Cordone, Susanna; Tattoli, Giacomo; Bevilacqua, Vitoantonio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Millán-Calenti, José C; Buján, Ana; Tortelli, Rosanna; Cardinali, Valentina; Barulli, Maria Rosaria; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Frisoni, Giovanni B; Del Percio, Claudio

    2016-01-01

    Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG) rhythms in groups of Alzheimer's disease (AD) compared to healthy elderly (Nold) subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA) estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), beta 2 (20-30 Hz), and gamma (30-40 Hz) were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC) higher than 0.7 as a threshold for a moderate classification rate (i.e., 70%). Results showed that the following EEG markers overcame this threshold: (i) central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii) central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii) frontal theta/alpha 1 current density; (iv) occipital delta/alpha 1 inter-hemispherical connectivity; (v) occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi) parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%). These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%. PMID:26941594

  20. Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders

    PubMed Central

    Gabard-Durnam, Laurel; Tierney, Adrienne L.; Vogel-Farley, Vanessa; Tager-Flusberg, Helen; Nelson, Charles A.

    2013-01-01

    An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of frontal EEG alpha asymmetry in ASD high-risk and low-risk infant populations. Our findings demonstrate that low and high-risk infants show different patterns of alpha asymmetry at 6 months of age and opposite growth trajectories in asymmetry over the following 12 months. These results support the candidacy of alpha asymmetry as an early neural ASD endophenotype. PMID:23989937

  1. Distribution of alpha-2-HS-glycoprotein (AHSG) phenotypes in Cabo Verde (west Africa): description of a new allele, AHSG*32.

    PubMed

    Caeiro, J L; Parra, E J; Yuasa, I; Teixeira, C; Llano, C

    1994-04-01

    The genetic polymorphism of alpha-2-HS-glycoprotein (AHSG) was studied in the population of Cabo Verde (West Africa), using isoelectric focusing in polyacrylamide gels followed by immunofixation-silver stain. AHSG frequencies are reported for the first time in a subsaharan African population. In addition to the common variants, AHSG 1 and AHSG 2, five AHSG variants were observed, including a new variant, tentatively designated AHSG 32. The allele frequencies were, AHSG*1: 0.7289, AHSG*2: 0.2111, AHSG*10: 0.0276, AHSG*3: 0.0162, AHSG*11: 0.0081, AHSG*22: 0.0065, AHSG*32:0.0016. PMID:7619771

  2. Quantitative EEG of Rapid-Eye-Movement Sleep: A Marker of Amnestic Mild Cognitive Impairment.

    PubMed

    Brayet, Pauline; Petit, Dominique; Frauscher, Birgit; Gagnon, Jean-François; Gosselin, Nadia; Gagnon, Katia; Rouleau, Isabelle; Montplaisir, Jacques

    2016-04-01

    The basal forebrain cholinergic system, which is impaired in early Alzheimer's disease, is more crucial for the activation of rapid-eye-movement (REM) sleep electroencephalogram (EEG) than it is for wakefulness. Quantitative EEG from REM sleep might thus provide an earlier and more accurate marker of the development of Alzheimer's disease in subjects with mild cognitive impairment (MCI) subjects than that from wakefulness. To assess the superiority of the REM sleep EEG as a screening tool for preclinical Alzheimer's disease, 22 subjects with amnestic MCI (a-MCI; 63.9±7.7 years), 10 subjects with nonamnestic MCI (na-MCI; 64.1±4.5 years) and 32 controls (63.7±6.6 years) participated in the study. Spectral analyses of the waking EEG and REM sleep EEG were performed and the [(delta+theta)/(alpha+beta)] ratio was used to assess between-group differences in EEG slowing. The a-MCI subgroup showed EEG slowing in frontal lateral regions compared to both na-MCI and control groups. This EEG slowing was present in wakefulness (compared to controls) but was much more prominent in REM sleep. Moreover, the comparison between amnestic and nonamnestic subjects was found significant only for the REM sleep EEG. There was no difference in EEG power ratio between na-MCI and controls for any of the 7 cortical regions studied. These findings demonstrate the superiority of the REM sleep EEG in the discrimination between a-MCI and both na-MCI and control subjects. PMID:26323578

  3. Altered resting-state EEG source functional connectivity in schizophrenia: the effect of illness duration

    PubMed Central

    Di Lorenzo, Giorgio; Daverio, Andrea; Ferrentino, Fabiola; Santarnecchi, Emiliano; Ciabattini, Fabio; Monaco, Leonardo; Lisi, Giulia; Barone, Ylenia; Di Lorenzo, Cherubino; Niolu, Cinzia; Seri, Stefano; Siracusano, Alberto

    2015-01-01

    Despite the increasing body of evidence supporting the hypothesis of schizophrenia as a disconnection syndrome, studies of resting-state EEG Source Functional Connectivity (EEG-SFC) in people affected by schizophrenia are sparse. The aim of the present study was to investigate resting-state EEG-SFC in 77 stable, medicated patients with schizophrenia (SCZ) compared to 78 healthy volunteers (HV). In order to study the effect of illness duration, SCZ were divided in those with a short duration of disease (SDD; n = 25) and those with a long duration of disease (LDD; n = 52). Resting-state EEG recordings in eyes closed condition were analyzed and lagged phase synchronization (LPS) indices were calculated for each ROI pair in the source-space EEG data. In delta and theta bands, SCZ had greater EEG-SFC than HV; a higher theta band connectivity in frontal regions was observed in LDD compared with SDD. In the alpha band, SCZ showed lower frontal EEG-SFC compared with HV whereas no differences were found between LDD and SDD. In the beta1 band, SCZ had greater EEG-SFC compared with HVs and in the beta2 band, LDD presented lower frontal and parieto-temporal EEG-SFC compared with HV. In the gamma band, SDD had greater connectivity values compared with LDD and HV. This study suggests that resting state brain network connectivity is abnormally organized in schizophrenia, with different patterns for the different EEG frequency components and that EEG can be a powerful tool to further elucidate the complexity of such disordered connectivity. PMID:25999835

  4. EEG Studies with Young Children.

    ERIC Educational Resources Information Center

    Flohr, John W.; Miller, Daniel C.; deBeus, Roger

    2000-01-01

    Describes how electroencephalogram (EEG) data are collected and how brain function is measured. Discusses studies on the effects of music experiences with adult subjects and studies focusing on the effects of music training on EEG activity of children and adolescents. Considers the implications of the studies and the future directions of this…

  5. REM sleep EEG spectral analysis in patients with first-episode schizophrenia.

    PubMed

    Poulin, Julie; Stip, Emmanuel; Godbout, Roger

    2008-10-01

    The pathophysiology of schizophrenia includes abnormalities in subcortical-cortical transfer of information that can be studied using REM sleep EEG spectral analysis, a measure that reflects spontaneous and endogenous thalamocortical activity. We recorded 10 patients with first-episode schizophrenia and 30 healthy controls for two consecutive nights in a sleep laboratory, using a 10-electrode EEG montage. Sixty seconds of REM sleep EEG without artifact were analyzed using FFT spectral analysis. Absolute and relative spectral amplitudes of five frequency bands (delta, theta, alpha, beta1 and beta2) were extracted and compared between the two groups. Frequency bands with significant differences were correlated with BPRS positive and negative symptoms scores. Patients with schizophrenia showed lower relative alpha and higher relative beta2 spectral amplitudes compared to healthy controls over the averaged total scalp. Analysis using cortical regions showed lower relative alpha over frontal, central and temporal regions and higher relative beta2 over the occipital region. Absolute spectral amplitude was not different between groups for any given EEG band. However, absolute alpha activity correlated negatively with BPRS positive symptoms scores and correlated positively with negative symptoms scores. Since similar results have been reported following EEG spectral analysis during the waking state, we conclude that abnormalities of subcortical-cortical transfer of information in schizophrenia could be generated by mechanisms common to REM sleep and waking. PMID:18280502

  6. A 6.4MB duplication of the alpha-synuclein locus causing fronto-temporal dementia and parkinsonism - phenotype-genotype correlations

    PubMed Central

    Kara, Eleanna; Kiely, Aoife P; Proukakis, Christos; Giffin, Nicola; Love, Seth; Hehir, Jason; Rantell, Khadija; Pandraud, Amelie; Hernandez, Dena G; Nacheva, Elizabeth; Pittman, Alan M; Nalls, Mike A; Singleton, Andrew B; Revesz, Tamas; Bhatia, Kailash P; Quinn, Niall; Hardy, John; Holton, Janice L; Houlden, Henry

    2015-01-01

    Importance SNCA locus duplications are associated with variable clinical features and reduced penetrance but the reasons underlying this variability are unknown. Objective 1) To report a novel family carrying a heterozygous 6.4Mb duplication of the SNCA locus with an atypical clinical presentation strongly reminiscent of frontotemporal dementia (FTD) and late-onset pallidopyramidal syndromes. 2) To study phenotype-genotype correlations in SNCA locus duplications. Design, Setting, Participants and Data sources We report the clinical and neuropathologic features of a family carrying a 6.4Mb duplication of the SNCA locus. To identify candidate disease modifiers, we undertake a genetic analysis in the family and conduct statistical analysis on previously published cases carrying SNCA locus duplication using regression modelling with robust standard errors to account for clustering at the family level. Main outcome measures To assess whether length of the SNCA locus duplication influences disease penetrance and severity, and whether extra-duplication factors have a disease-modifying role. Results We identified a large 6.4Mb duplication of the SNCA locus in this family. Neuropathological analysis showed extensive α-synuclein pathology with minimal phospho-tau pathology. Genetic analysis showed an increased burden of PD-related risk factors and the disease-predisposing H1/H1 MAPT haplotype. Statistical analysis of previously published cases suggested that there is a trend towards increasing disease severity and disease penetrance with increasing duplication size. The corresponding odds ratios (95% CI) from the univariate analyses were 1.17 (0.81 to 1.68) and 1.34 (0.78 to 2.31) respectively. Gender was significantly associated with both disease risk and severity; males compared to females had increased disease risk and severity and the corresponding odds ratios (95% CI) from the univariate analyses were 8.36 (1.97 to 35.42) and 5.55 (1.39 to 22.22) respectively

  7. What can be found in scalp EEG spectrum beyond common frequency bands. EEG–fMRI study

    NASA Astrophysics Data System (ADS)

    Marecek, R.; Lamos, M.; Mikl, M.; Barton, M.; Fajkus, J.; I, Rektor; Brazdil, M.

    2016-08-01

    Objective. The scalp EEG spectrum is a frequently used marker of neural activity. Commonly, the preprocessing of EEG utilizes constraints, e.g. dealing with a predefined subset of electrodes or a predefined frequency band of interest. Such treatment of the EEG spectrum neglects the fact that particular neural processes may be reflected in several frequency bands and/or several electrodes concurrently, and can overlook the complexity of the structure of the EEG spectrum. Approach. We showed that the EEG spectrum structure can be described by parallel factor analysis (PARAFAC), a method which blindly uncovers the spatial–temporal–spectral patterns of EEG. We used an algorithm based on variational Bayesian statistics to reveal nine patterns from the EEG of 38 healthy subjects, acquired during a semantic decision task. The patterns reflected neural activity synchronized across theta, alpha, beta and gamma bands and spread over many electrodes, as well as various EEG artifacts. Main results. Specifically, one of the patterns showed significant correlation with the stimuli timing. The correlation was higher when compared to commonly used models of neural activity (power fluctuations in distinct frequency band averaged across a subset of electrodes) and we found significantly correlated hemodynamic fluctuations in simultaneously acquired fMRI data in regions known to be involved in speech processing. Further, we show that the pattern also occurs in EEG data which were acquired outside the MR machine. Two other patterns reflected brain rhythms linked to the attentional and basal ganglia large scale networks. The other patterns were related to various EEG artifacts. Significance. These results show that PARAFAC blindly identifies neural activity in the EEG spectrum and that it naturally handles the correlations among frequency bands and electrodes. We conclude that PARAFAC seems to be a powerful tool for analysis of the EEG spectrum and might bring novel insight to the

  8. Levels of alpha-toxin correlate with distinct phenotypic response profiles of blood mononuclear cells and with agr background of community-associated Staphylococcus aureus isolates.

    PubMed

    Mairpady Shambat, Srikanth; Haggar, Axana; Vandenesch, Francois; Lina, Gerard; van Wamel, Willem J B; Arakere, Gayathri; Svensson, Mattias; Norrby-Teglund, Anna

    2014-01-01

    Epidemiological studies of Staphylococcus aureus have shown a relation between certain clones and the presence of specific virulence genes, but how this translates into virulence-associated functional responses is not fully elucidated. Here we addressed this issue by analyses of community-acquired S. aureus strains characterized with respect to antibiotic resistance, ST types, agr types, and virulence gene profiles. Supernatants containing exotoxins were prepared from overnight bacterial cultures, and tested in proliferation assays using human peripheral blood mononuclear cells (PBMC). The strains displayed stable phenotypic response profiles, defined by either a proliferative or cytotoxic response. Although, virtually all strains elicited superantigen-mediated proliferative responses, the strains with a cytotoxic profile induced proliferation only in cultures with the most diluted supernatants. This indicated that the superantigen-response was masked by a cytotoxic effect which was also confirmed by flow cytometry analysis. The cytotoxic supernatants contained significantly higher levels of α-toxin than did the proliferative supernatants. Addition of α-toxin to supernatants characterized as proliferative switched the response into cytotoxic profiles. In contrast, no effect of Panton Valentine Leukocidin, δ-toxin or phenol soluble modulin α-3 was noted in the proliferative assay. Furthermore, a significant association between agr type and phenotypic profile was found, where agrII and agrIII strains had predominantly a proliferative profile whereas agrI and IV strains had a predominantly cytotoxic profile. The differential response profiles associated with specific S. aureus strains with varying toxin production could possibly have an impact on disease manifestations, and as such may reflect specific pathotypes. PMID:25166615

  9. The alpha-galactosidase A p.Arg118Cys variant does not cause a Fabry disease phenotype: data from individual patients and family studies

    PubMed Central

    Ferreira, Susana; Ortiz, Alberto; Germain, Dominique P.; Viana-Baptista, Miguel; Gomes, António Caldeira; Camprecios, Marta; Fenollar-Cortés, Maria; Gallegos-Villalobos, Ángel; Garcia, Diego; García-Robles, José Antonio; Egido, Jesús; Gutiérrez-Rivas, Eduardo; Herrero, José Antonio; Mas, Sebastián; Oancea, Raluca; Péres, Paloma; Salazar-Martín, Luis Manuel; Solera-Garcia, Jesús; Alves, Helena; Garman, Scott C.; Oliveira, João Paulo

    2015-01-01

    Summary Lysosomal α-galactosidase A (α-Gal) is the enzyme deficient in Fabry disease (FD), an X-linked glycosphingolipidosis caused by pathogenic mutations affecting the GLA gene. The early-onset, multi-systemic FD classical phenotype is associated with absent or severe enzyme deficiency, as measured by in vitro assays, but patients with higher levels of residual α-Gal activity may have later-onset, more organ-restricted clinical presentations. A change in the codon 118 of the wild-type α-Gal sequence, replacing basic arginine by a potentially sulfhydryl-binding cysteine residue – GLA p.(Arg118Cys) –, has been recurrently described in large FD screening studies of high-risk patients. Although the Cys118 allele is associated with high residual α-Gal activity in vitro, it has been classified as a pathogenic mutation, mainly on the basis of theoretical arguments about the chemistry of the cysteine residue. However its pathogenicity has never been convincingly demonstrated by pathology criteria. We reviewed the clinical, biochemical and histopathology data obtained from 22 individuals of Portuguese and Spanish ancestry carrying the Cys118 allele, including 3 homozygous females. Cases were identified either on the differential diagnosis of possible FD manifestations and on case-finding studies (n=11; 4 males), or on unbiased cascade screening of probands’ close relatives (n=11; 3 males). Overall, those data strongly suggest that the GLA p.(Arg118Cys) variant does not segregate with FD clinical phenotypes in a Mendelian fashion, but might be a modulator of the multifactorial risk of cerebrovascular disease, since the allelic frequency in stroke patients was 0.0087 (p=0.0185 vs the general population). The Cys118 allelic frequency in healthy Portuguese adults (n=696) has been estimated as 0.001, therefore not qualifying for “rare” condition. PMID:25468652

  10. Dry EEG Electrodes

    PubMed Central

    Lopez-Gordo, M. A.; Sanchez-Morillo, D.; Valle, F. Pelayo

    2014-01-01

    Electroencephalography (EEG) emerged in the second decade of the 20th century as a technique for recording the neurophysiological response. Since then, there has been little variation in the physical principles that sustain the signal acquisition probes, otherwise called electrodes. Currently, new advances in technology have brought new unexpected fields of applications apart from the clinical, for which new aspects such as usability and gel-free operation are first order priorities. Thanks to new advances in materials and integrated electronic systems technologies, a new generation of dry electrodes has been developed to fulfill the need. In this manuscript, we review current approaches to develop dry EEG electrodes for clinical and other applications, including information about measurement methods and evaluation reports. We conclude that, although a broad and non-homogeneous diversity of approaches has been evaluated without a consensus in procedures and methodology, their performances are not far from those obtained with wet electrodes, which are considered the gold standard, thus enabling the former to be a useful tool in a variety of novel applications. PMID:25046013

  11. [Quantitative EEG analysis of a single dose of psychotropic drugs in healthy probands].

    PubMed

    Fischer, W; Streubel, F R; Heydenreich, F; Rabending, G

    1986-08-01

    In a series of 74 experiments in a double blind study, 25 healthy test persons were medicated with a single dose of Clomipramin, Desipramin, Imipramin, Diazepam, Carbamazepin, Haloperidol, and a placebo. At the end of one hour, and again at the end of three hours, an EEG was made whose frequency analysis revealed significant changes in about half the test persons. The antidepressives induced an increase in the theta waves, the slow alpha waves, and the slow beta waves, and a decrease in the fast alpha waves. The factors influencing the EEG are discussed. PMID:3786575

  12. EEG Recording and Analysis for Sleep Research

    PubMed Central

    Campbell, Ian G.

    2010-01-01

    The electroencephalogram (EEG) is the most common tool used in sleep research. This unit describes the methods for recording and analyzing the EEG. Detailed protocols describe recorder calibration, electrode application, EEG recording, and computer EEG analysis with power spectral analysis. Computer digitization of an analog EEG signal is discussed, along with EEG filtering and the parameters of fast Fourier transform (FFT) power spectral analysis. Sample data are provided for a typical night's analysis of EEG during NREM (non-REM) and REM sleep. PMID:19802813

  13. The EEG measurement technique under exercising.

    PubMed

    Hosaka, Naoya; Tanaka, Junya; Koyama, Akira; Magatani, Kazushige

    2006-01-01

    Our purpose of the research is a development of the detecting method of EEG under exercising. Usually, measuring EEG is done in the quiet state. In case of the measuring EEG under exercising, a movement of the body causes vibration of electrodes and artifact for the EEG. Therefore, generally detection of the EEG under exercising is said to be difficult. So, we developed the measuring method of EEG under exercising by using algorithm that we designed. Five normal subjects were tested with our method, and EEG without artifact was able to be measured in all cases. PMID:17945632

  14. EEG recording and analysis for sleep research.

    PubMed

    Campbell, Ian G

    2009-10-01

    The electroencephalogram (EEG) is the most common tool used in sleep research. This unit describes the methods for recording and analyzing the EEG. Detailed protocols describe recorder calibration, electrode application, EEG recording, and computer EEG analysis with power spectral analysis. Computer digitization of an analog EEG signal is discussed, along with EEG filtering and the parameters of fast Fourier transform (FFT) power spectral analysis. Sample data are provided for a typical night's analysis of EEG during NREM (non-REM) and REM sleep. PMID:19802813

  15. Does greater low frequency EEG activity in normal immaturity and in children with epilepsy arise in the same neuronal network?

    PubMed

    Michels, L; Bucher, K; Brem, S; Halder, P; Lüchinger, R; Liechti, M; Martin, E; Jeanmonod, D; Kröll, J; Brandeis, D

    2011-03-01

    Greater low frequency power (<8 Hz) in the electroencephalogram (EEG) at rest is normal in the immature developing brain of children when compared to adults. Children with epilepsy also have greater low frequency interictal resting EEG activity. Whether these power elevations reflect brain immaturity due to a developmental lag or the underlying epileptic pathophysiology is unclear. The present study addresses this question by analyzing spectral EEG topographies and sources for normally developing children and children with epilepsy. We first compared the resting EEG of healthy children to that of healthy adults to isolate effects related to normal brain immaturity. Next, we compared the EEG from 10 children with generalized cryptogenic epilepsy to the EEG of 24 healthy children to isolate effects related to epilepsy. Spectral analysis revealed that global low (delta: 1-3 Hz, theta: 4-7 Hz), medium (alpha: 8-12 Hz) and high (beta: 13-25 Hz) frequency EEG activity was greater in children without epilepsy compared to adults, and even further elevated for children with epilepsy. Topographical and tomographic EEG analyses showed that normal immaturity corresponded to greater delta and theta activity at fronto-central scalp and brain regions, respectively. In contrast, the epilepsy-related activity elevations were predominantly in the alpha band at parieto-occipital electrodes and brain regions, respectively. We conclude that lower frequency activity can be a sign of normal brain immaturity or brain pathology depending on the specific topography and frequency of the oscillating neuronal network. PMID:20820898

  16. A capacitive, biocompatible and adhesive electrode for long-term and cap-free monitoring of EEG signals

    NASA Astrophysics Data System (ADS)

    Lee, Seung Min; Kim, Jeong Hun; Byeon, Hang Jin; Choi, Yoon Young; Park, Kwang Suk; Lee, Sang-Hoon

    2013-06-01

    Objective. Long-term electroencephalogram (EEG) monitoring broadens EEG applications to various areas, but it requires cap-free recording of EEG signals. Our objective here is to develop a capacitive, small-sized, adhesive and biocompatible electrode for the cap-free and long-term EEG monitoring. Approach. We have developed an electrode made of polydimethylsiloxane (PDMS) and adhesive PDMS for EEG monitoring. This electrode can be attached to a hairy scalp and be completely hidden by the hair. We tested its electrical and mechanical (adhesive) properties by measuring voltage gain to frequency and adhesive force using 30 repeat cycles of the attachment and detachment test. Electrode performance on EEG was evaluated by alpha rhythm detection and measuring steady state visually evoked potential and N100 auditory evoked potential. Main results. We observed the successful recording of alpha rhythm and evoked signals to diverse stimuli with high signal quality. The biocompatibility of the electrode was verified and a survey found that the electrode was comfortable and convenient to wear. Significance. These results indicate that the proposed EEG electrode is suitable and convenient for long term EEG monitoring.

  17. Genetic control of ethanol action on the central nervous system. An EEG study in twins.

    PubMed

    Propping, P

    1977-03-14

    The purpose of the investigation is to claify the genetic contribution to the interindividual variability of ethanol action on the central nervous system. The 52 adult male healthy twin pairs (26 MZ, 26 DZ) got 1.2 ml/kg ethanol p.o. under standardized conditions; furthermore, 13 non-twin subjects were repeatedly subjected to the same procedure in order to test the intraindividual variability. The EEG was recorded before and 60, 120, 180, and 240 min after alcohol intake. The EEGs were off-line analyzed by means of a computer program for time domain analysis. As was already known, on the average alcohol led to a better synchronisation of the EEG, i.e., the number of beta-waves decreased whereas the number of alpha- and theta-waves increased. The extent of the alcohol effect on the EEG varied enormously between individuals; however, the EEGs of MZ twins proved to react indentically to alcohol loading, whereas the EEGs of DZ twins became mor dissimilar during the course of the experiment. The low-voltage EEG presumably is resistant to alchohol; furthermore, it is supposed that there exists a special beta-prone EEG-type which is also genetic in origin. The identical EEG reaction of MZ twins to alcohol loading could not be attributed to more similar blood alcohol concentrations. It is hypothesized that the differences in the extent of the alcohol effect on the EEG between individuals might reflect differences in the sensitivity of the ascending reticular activating system. In the literature it has frequently been reported that alcoholics have preferentially brain wave patterns which are poorly synchronized. These findings are discussed in the light of the present results. PMID:557449

  18. Ballistocardiogram Artifact Removal with a Reference Layer and Standard EEG Cap

    PubMed Central

    Luo, Qingfei; Huang, Xiaoshan; Glover, Gary H.

    2014-01-01

    Background In simultaneous EEG-fMRI, the EEG recordings are severely contaminated by ballistocardiogram (BCG) artifacts, which are caused by cardiac pulsations. To reconstruct and remove the BCG artifacts, one promising method is to measure the artifacts in the absence of EEG signal by placing a group of electrodes (BCG electrodes) on a conductive layer (reference layer) insulated from the scalp. However, current BCG reference layer (BRL) methods either use a customized EEG cap composed of electrode pairs, or need to construct the custom reference layer through additional model-building experiments for each EEG-fMRI experiment. These requirements have limited the versatility and efficiency of BRL. The aim of this study is to propose a more practical and efficient BRL method and compare its performance with the most popular BCG removal method, the optimal basis sets (OBS) algorithm. New Method By designing the reference layer as a permanent and reusable cap, the new BRL method is able to be used with a standard EEG cap, and no extra experiments and preparations are needed to use the BRL in an EEG-fMRI experiment. Results The BRL method effectively removed the BCG artifacts from both oscillatory and evoked potential scalp recordings and recovered the EEG signal. Comparison with Existing Method Compared to the OBS, this new BRL method improved the contrast-to-noise ratios of the alpha-wave, visual, and auditory evoked potential signals by 101%, 76%, and 75% respectively, employing 160 BCG electrodes. Using only 20 BCG electrodes, the BRL improved the EEG signal by 74%/26%/41% respectively. Conclusion The proposed method can substantially improve the EEG signal quality compared with traditional methods. PMID:24960423

  19. Prognostically important EEG coma patterns in diffuse anoxic and traumatic encephalopathies in adults.

    PubMed

    Synek, V M

    1988-04-01

    Because of the paucity in the English literature of a detailed and universally accepted EEG grading scale relating to survival after diffuse traumatic and anoxic brain insults, prognostically oriented EEG patterns including recently described abnormalities are presented and discussed. The significance of these patterns may also apply in cases of coma of other etiologies, which can present morphologically similar features. EEG patterns have been classified into five major grades based on an internationally accepted scale. Individual patterns have been more clearly defined on the basis of the morphology of dominant activities, their distribution, persistence, and reactivity to external stimulation. Favorable outcome with survival seems to occur with both grade 1 and the "reactive type" of grade 2 abnormalities, with preservation of normal sleep features, and with frontal monorhythmic delta activity. Prognostically uncertain patterns are "nonreactive" grade 2 abnormalities, diffuse delta activity with grade 3 abnormality, and the "reactive type of alpha pattern coma." The following patterns are suggested to be prognostically malignant if persistent: grade 3 abnormality with small amplitude, diffuse, irregular delta activity; grade 4 ("burst suppression pattern"), in particular when epileptiform discharges are present and with "low-output EEG"; and grade 5 ("isoelectric EEG"). Fatal outcome is also common with the "nonreactive type of alpha pattern coma" and the recently reported "theta pattern coma." These patterns are presented in the illustrations. It is intended that this more detailed subdivision will promote understanding between electroencephalographers using visual EEG assessment in cases of coma. PMID:3074973

  20. Envelope responses in single-trial EEG indicate attended speaker in a “cocktail party”

    PubMed Central

    Horton, Cort; Srinivasan, Ramesh; D’Zmura, Michael

    2014-01-01

    Objective Recent studies have shown that auditory cortex better encodes the envelope of attended speech than that of unattended speech during multi-speaker (“cocktail party”) situations. We investigated whether these differences were sufficiently robust within single-trial EEG data to accurately determine where subjects attended. Additionally, we compared this measure to other established EEG markers of attention. Approach High-resolution EEG was recorded while subjects engaged in a two-speaker “cocktail party” task. Cortical responses to speech envelopes were extracted by cross-correlating the envelopes with each EEG channel. We also measured steady-state responses (elicited via high-frequency amplitude modulation of the speech) and alpha-band power, both of which have been sensitive to attention in previous studies. Using linear classifiers, we then examined how well each of these features could be used to predict the subjects’ side of attention at various epoch lengths. Main Results We found that the attended speaker could be determined reliably from the envelope responses calculated from short periods of EEG, with accuracy improving as a function of sample length. Furthermore, envelope responses were far better indicators of attention than changes in either alpha power or steady-state responses. Significance These results suggest that envelope-related signals recorded in EEG data can be used to form robust auditory BCI’s that do not require artificial manipulation (e.g., amplitude modulation) of stimuli to function. PMID:24963838

  1. Envelope responses in single-trial EEG indicate attended speaker in a ‘cocktail party’

    NASA Astrophysics Data System (ADS)

    Horton, Cort; Srinivasan, Ramesh; D'Zmura, Michael

    2014-08-01

    Objective. Recent studies have shown that auditory cortex better encodes the envelope of attended speech than that of unattended speech during multi-speaker (‘cocktail party’) situations. We investigated whether these differences were sufficiently robust within single-trial electroencephalographic (EEG) data to accurately determine where subjects attended. Additionally, we compared this measure to other established EEG markers of attention. Approach. High-resolution EEG was recorded while subjects engaged in a two-speaker ‘cocktail party’ task. Cortical responses to speech envelopes were extracted by cross-correlating the envelopes with each EEG channel. We also measured steady-state responses (elicited via high-frequency amplitude modulation of the speech) and alpha-band power, both of which have been sensitive to attention in previous studies. Using linear classifiers, we then examined how well each of these features could be used to predict the subjects’ side of attention at various epoch lengths. Main results. We found that the attended speaker could be determined reliably from the envelope responses calculated from short periods of EEG, with accuracy improving as a function of sample length. Furthermore, envelope responses were far better indicators of attention than changes in either alpha power or steady-state responses. Significance. These results suggest that envelope-related signals recorded in EEG data can be used to form robust auditory BCI’s that do not require artificial manipulation (e.g., amplitude modulation) of stimuli to function.

  2. High-resolution EEG (HR-EEG) and magnetoencephalography (MEG).

    PubMed

    Gavaret, M; Maillard, L; Jung, J

    2015-03-01

    High-resolution EEG (HR-EEG) and magnetoencephalography (MEG) allow the recording of spontaneous or evoked electromagnetic brain activity with excellent temporal resolution. Data must be recorded with high temporal resolution (sampling rate) and high spatial resolution (number of channels). Data analyses are based on several steps with selection of electromagnetic signals, elaboration of a head model and use of algorithms in order to solve the inverse problem. Due to considerable technical advances in spatial resolution, these tools now represent real methods of ElectroMagnetic Source Imaging. HR-EEG and MEG constitute non-invasive and complementary examinations, characterized by distinct sensitivities according to the location and orientation of intracerebral generators. In the presurgical assessment of drug-resistant partial epilepsies, HR-EEG and MEG can characterize and localize interictal activities and thus the irritative zone. HR-EEG and MEG often yield significant additional data that are complementary to other presurgical investigations and particularly relevant in MRI-negative cases. Currently, the determination of the epileptogenic zone and functional brain mapping remain rather less well-validated indications. In France, in 2014, HR-EEG is now part of standard clinical investigation of epilepsy, while MEG remains a research technique. PMID:25648821

  3. Hypoxia-inducible factor 1 alpha is required for the tumourigenic and aggressive phenotype associated with Rab25 expression in ovarian cancer

    PubMed Central

    Gomez-Roman, Natividad; Sahasrabudhe, Neha Mohan; McGregor, Fiona; Chalmers, Anthony J.; Cassidy, Jim; Plumb, Jane

    2016-01-01

    The small GTPase Rab25 has been functionally linked to tumour progression and aggressiveness in ovarian cancer and promotes invasion in three-dimensional environments. This type of migration has been shown to require the expression of the hypoxia-inducible factor 1 alpha (HIF-1α). In this report we demonstrate that Rab25 regulates HIF-1α protein expression in an oxygen independent manner in a panel of cancer cell lines. Regulation of HIF-1α protein expression by Rab25 did not require transcriptional upregulation, but was dependent on de novo protein synthesis through the Erbb2/ERK1/2 and p70S6K/mTOR pathways. Rab25 expression induced HIF-1 transcriptional activity, increased cisplatin resistance, and conferred intraperitoneal growth to the A2780 cell line in immunocompromised mice. Targeting HIF1 activity by silencing HIF-1β re-sensitised cells to cisplatin in vitro and reduced tumour formation of A2780-Rab25 expressing cells in vivo in a mouse ovarian peritoneal carcinomatosis model. Similar effects on cisplatin resistance in vitro and intraperitoneal tumourigenesis in vivo were obtained after HIF1b knockdown in the ovarian cancer cell line SKOV3, which expresses endogenous Rab25 and HIF-1α at atmospheric oxygen concentrations. Our results suggest that Rab25 tumourigenic potential and chemoresistance relies on HIF1 activity in aggressive and metastatic ovarian cancer. Targeting HIF-1 activity may potentially be effective either alone or in combination with standard chemotherapy for aggressive metastatic ovarian cancer. PMID:26967059

  4. CNT/PDMS-based canal-typed ear electrodes for inconspicuous EEG recording

    NASA Astrophysics Data System (ADS)

    Lee, Joong Hoon; Lee, Seung Min; Byeon, Hang Jin; Hong, Joung Sook; Park, Kwang Suk; Lee, Sang-Hoon

    2014-08-01

    Objective. Current electroencephalogram (EEG) monitoring systems typically require cumbersome electrodes that must be pasted on a scalp, making a private recording of an EEG in a public place difficult. We have developed a small, user friendly, biocompatible electrode with a good appearance for inconspicuous EEG monitoring. Approach. We fabricated carbon nanotube polydimethylsiloxane (CNT/PDMS)-based canal-type ear electrodes (CEE) for EEG recording. These electrodes have an additional function, triggering sound stimulation like earphones and recording EEG simultaneously for auditory brain-computer interface (BCI). The electrode performance was evaluated by a standard EEG measurement paradigm, including the detection of alpha rhythms and measurements of N100 auditory evoked potential (AEP), steady-state visual evoked potential (SSVEP) and auditory steady-state response (ASSR). Furthermore, the bio- and skin-compatibility of CNT/PDMS were tested. Main results. All feasibility studies were successfully recorded with the fabricated electrodes, and the biocompatibility of CNT/PDMS was also proved. Significance. These electrodes could be used to monitor EEG clinically, in ubiquitous health care and in brain-computer interfaces.

  5. Bristle-sensors—low-cost flexible passive dry EEG electrodes for neurofeedback and BCI applications

    NASA Astrophysics Data System (ADS)

    Grozea, Cristian; Voinescu, Catalin D.; Fazli, Siamac

    2011-04-01

    In this paper, we present a new, low-cost dry electrode for EEG that is made of flexible metal-coated polymer bristles. We examine various standard EEG paradigms, such as capturing occipital alpha rhythms, testing for event-related potentials in an auditory oddball paradigm and performing a sensory motor rhythm-based event-related (de-) synchronization paradigm to validate the performance of the novel electrodes in terms of signal quality. Our findings suggest that the dry electrodes that we developed result in high-quality EEG recordings and are thus suitable for a wide range of EEG studies and BCI applications. Furthermore, due to the flexibility of the novel electrodes, greater comfort is achieved in some subjects, this being essential for long-term use.

  6. Bristle-sensors--low-cost flexible passive dry EEG electrodes for neurofeedback and BCI applications.

    PubMed

    Grozea, Cristian; Voinescu, Catalin D; Fazli, Siamac

    2011-04-01

    In this paper, we present a new, low-cost dry electrode for EEG that is made of flexible metal-coated polymer bristles. We examine various standard EEG paradigms, such as capturing occipital alpha rhythms, testing for event-related potentials in an auditory oddball paradigm and performing a sensory motor rhythm-based event-related (de-) synchronization paradigm to validate the performance of the novel electrodes in terms of signal quality. Our findings suggest that the dry electrodes that we developed result in high-quality EEG recordings and are thus suitable for a wide range of EEG studies and BCI applications. Furthermore, due to the flexibility of the novel electrodes, greater comfort is achieved in some subjects, this being essential for long-term use. PMID:21436526

  7. Monitoring task loading with multivariate EEG measures during complex forms of human-computer interaction

    NASA Technical Reports Server (NTRS)

    Smith, M. E.; Gevins, A.; Brown, H.; Karnik, A.; Du, R.

    2001-01-01

    Electroencephalographic (EEG) recordings were made while 16 participants performed versions of a personal-computer-based flight simulation task of low, moderate, or high difficulty. As task difficulty increased, frontal midline theta EEG activity increased and alpha band activity decreased. A participant-specific function that combined multiple EEG features to create a single load index was derived from a sample of each participant's data and then applied to new test data from that participant. Index values were computed for every 4 s of task data. Across participants, mean task load index values increased systematically with increasing task difficulty and differed significantly between the different task versions. Actual or potential applications of this research include the use of multivariate EEG-based methods to monitor task loading during naturalistic computer-based work.

  8. Optimizing microsurgical skills with EEG neurofeedback

    PubMed Central

    Ros, Tomas; Moseley, Merrick J; Bloom, Philip A; Benjamin, Larry; Parkinson, Lesley A; Gruzelier, John H

    2009-01-01

    Background By enabling individuals to self-regulate their brainwave activity in the field of optimal performance in healthy individuals, neurofeedback has been found to improve cognitive and artistic performance. Here we assessed whether two distinct EEG neurofeedback protocols could develop surgical skill, given the important role this skill plays in medicine. Results National Health Service trainee ophthalmic microsurgeons (N = 20) were randomly assigned to either Sensory Motor Rhythm-Theta (SMR) or Alpha-Theta (AT) groups, a randomized subset of which were also part of a wait-list 'no-treatment' control group (N = 8). Neurofeedback groups received eight 30-minute sessions of EEG training. Pre-post assessment included a skills lab surgical procedure with timed measures and expert ratings from video-recordings by consultant surgeons, together with state/trait anxiety self-reports. SMR training demonstrated advantages absent in the control group, with improvements in surgical skill according to 1) the expert ratings: overall technique (d = 0.6, p < 0.03) and suture task (d = 0.9, p < 0.02) (judges' intraclass correlation coefficient = 0.85); and 2) with overall time on task (d = 0.5, p = 0.02), while everyday anxiety (trait) decreased (d = 0.5, p < 0.02). Importantly the decrease in surgical task time was strongly associated with SMR EEG training changes (p < 0.01), especially with continued reduction of theta (4–7 Hz) power. AT training produced marginal improvements in technique and overall performance time, which were accompanied by a standard error indicative of large individual differences. Notwithstanding, successful within session elevation of the theta-alpha ratio correlated positively with improvements in overall technique (r = 0.64, p = 0.047). Conclusion SMR-Theta neurofeedback training provided significant improvement in surgical technique whilst considerably reducing time on task by 26%. There was also evidence that AT training marginally reduced

  9. [EEG manifestations in metabolic encephalopathy].

    PubMed

    Lin, Chou-Ching K

    2005-09-01

    Normal brain function depends on normal neuronal metabolism, which is closely related to systemic homeostasis of metabolites, such as glucose, electrolytes, amino acids and ammonia. "Metabolic encephalopathy" indicates diffuse brain dysfunction caused by various systemic derangements. Electroencephalogram (EEG) is widely used to evaluate metabolic encephalopathy since 1937, when Berger first observed slow brain activity induced by hypoglycemia. EEG is most useful in differentiating organic from psychiatric conditions, identifying epileptogenicity, and providing information about the degree of cortical or subcortical dysfunction. In metabolic encephalopathy, EEG evolution generally correlates well with the severity of encephalopathy. However, EEG has little specificity in differentiating etiologies in metabolic encephalopathy. For example, though triphasic waves are most frequently mentioned in hepatic encephalopathy, they can also be seen in uremic encephalopathy, or even in aged psychiatric patients treated with lithium. Spike-and-waves may appear in hyper- or hypo-glycemia, uremic encephalopathy, or vitamin deficiencies, etc. Common principles of EEG changes in metabolic encephalopathy are (1) varied degrees of slowing, (2) assorted mixtures of epileptic discharge, (3) high incidence of triphasic waves, and (4), as a rule, reversibility after treatment of underlying causes. There are some exceptions to the above descriptions in specific metabolic disorders and EEG manifestations are highly individualized. PMID:16252619

  10. Identifying Objective EEG Based Markers of Linear Vection in Depth

    PubMed Central

    Palmisano, Stephen; Barry, Robert J.; De Blasio, Frances M.; Fogarty, Jack S.

    2016-01-01

    This proof-of-concept study investigated whether a time-frequency EEG approach could be used to examine vection (i.e., illusions of self-motion). In the main experiment, we compared the event-related spectral perturbation (ERSP) data of 10 observers during and directly after repeated exposures to two different types of optic flow display (each was 35° wide by 29° high and provided 20 s of motion stimulation). Displays consisted of either a vection display (which simulated constant velocity forward self-motion in depth) or a control display (a spatially scrambled version of the vection display). ERSP data were decomposed using time-frequency Principal Components Analysis (t–f PCA). We found an increase in 10 Hz alpha activity, peaking some 14 s after display motion commenced, which was positively associated with stronger vection ratings. This followed decreases in beta activity, and was also followed by a decrease in delta activity; these decreases in EEG amplitudes were negatively related to the intensity of the vection experience. After display motion ceased, a series of increases in the alpha band also correlated with vection intensity, and appear to reflect vection- and/or motion-aftereffects, as well as later cognitive preparation for reporting the strength of the vection experience. Overall, these findings provide support for the notion that EEG can be used to provide objective markers of changes in both vection status (i.e., “vection/no vection”) and vection strength. PMID:27559328

  11. Identifying Objective EEG Based Markers of Linear Vection in Depth.

    PubMed

    Palmisano, Stephen; Barry, Robert J; De Blasio, Frances M; Fogarty, Jack S

    2016-01-01

    This proof-of-concept study investigated whether a time-frequency EEG approach could be used to examine vection (i.e., illusions of self-motion). In the main experiment, we compared the event-related spectral perturbation (ERSP) data of 10 observers during and directly after repeated exposures to two different types of optic flow display (each was 35° wide by 29° high and provided 20 s of motion stimulation). Displays consisted of either a vection display (which simulated constant velocity forward self-motion in depth) or a control display (a spatially scrambled version of the vection display). ERSP data were decomposed using time-frequency Principal Components Analysis (t-f PCA). We found an increase in 10 Hz alpha activity, peaking some 14 s after display motion commenced, which was positively associated with stronger vection ratings. This followed decreases in beta activity, and was also followed by a decrease in delta activity; these decreases in EEG amplitudes were negatively related to the intensity of the vection experience. After display motion ceased, a series of increases in the alpha band also correlated with vection intensity, and appear to reflect vection- and/or motion-aftereffects, as well as later cognitive preparation for reporting the strength of the vection experience. Overall, these findings provide support for the notion that EEG can be used to provide objective markers of changes in both vection status (i.e., "vection/no vection") and vection strength. PMID:27559328

  12. Machine learning identification of EEG features predicting working memory performance in schizophrenia and healthy adults

    PubMed Central

    Johannesen, Jason K.; Bi, Jinbo; Jiang, Ruhua; Kenney, Joshua G.; Chen, Chi-Ming A.

    2016-01-01

    Background With millisecond-level resolution, electroencephalographic (EEG) recording provides a sensitive tool to assay neural dynamics of human cognition. However, selection of EEG features used to answer experimental questions is typically determined a priori. The utility of machine learning was investigated as a computational framework for extracting the most relevant features from EEG data empirically. Methods Schizophrenia (SZ; n = 40) and healthy community (HC; n = 12) subjects completed a Sternberg Working Memory Task (SWMT) during EEG recording. EEG was analyzed to extract 5 frequency components (theta1, theta2, alpha, beta, gamma) at 4 processing stages (baseline, encoding, retention, retrieval) and 3 scalp sites (frontal-Fz, central-Cz, occipital-Oz) separately for correctly and incorrectly answered trials. The 1-norm support vector machine (SVM) method was used to build EEG classifiers of SWMT trial accuracy (correct vs. incorrect; Model 1) and diagnosis (HC vs. SZ; Model 2). External validity of SVM models was examined in relation to neuropsychological test performance and diagnostic classification using conventional regression-based analyses. Results SWMT performance was significantly reduced in SZ (p < .001). Model 1 correctly classified trial accuracy at 84 % in HC, and at 74 % when cross-validated in SZ data. Frontal gamma at encoding and central theta at retention provided highest weightings, accounting for 76 % of variance in SWMT scores and 42 % variance in neuropsychological test performance across samples. Model 2 identified frontal theta at baseline and frontal alpha during retrieval as primary classifiers of diagnosis, providing 87 % classification accuracy as a discriminant function. Conclusions EEG features derived by SVM are consistent with literature reports of gamma’s role in memory encoding, engagement of theta during memory retention, and elevated resting low-frequency activity in schizophrenia. Tests of model performance and cross

  13. Gender differences in association between serotonin transporter gene polymorphism and resting-state EEG activity.

    PubMed

    Volf, N V; Belousova, L V; Knyazev, G G; Kulikov, A V

    2015-01-22

    Human brain oscillations represent important features of information processing and are highly heritable. Gender has been observed to affect association between the 5-HTTLPR (serotonin-transporter-linked polymorphic region) polymorphism and various endophenotypes. This study aimed to investigate the effects of 5-HTTLPR on the spontaneous electroencephalography (EEG) activity in healthy male and female subjects. DNA samples extracted from buccal swabs and resting EEG recorded at 60 standard leads were collected from 210 (101 men and 109 women) volunteers. Spectral EEG power estimates and cortical sources of EEG activity were investigated. It was shown that effects of 5-HTTLPR polymorphism on electrical activity of the brain vary as a function of gender. Women with the S/L genotype had greater global EEG power compared to men with the same genotype. In men, current source density was markedly different among genotype groups in only alpha 2 and alpha 3 frequency ranges: S/S allele carriers had higher current source density estimates in the left inferior parietal lobule in comparison with the L/L group. In women, genotype difference in global power asymmetry was found in the central-temporal region. Contrasting L/L and S/L genotype carriers also yielded significant effects in the right hemisphere inferior parietal lobule and the right postcentral gyrus with L/L genotype carriers showing lower current source density estimates than S/L genotype carriers in all but gamma bands. So, in women, the effects of 5-HTTLPR polymorphism were associated with modulation of the EEG activity in a wide range of EEG frequencies. The significance of the results lies in the demonstration of gene by sex interaction with resting EEG that has implications for understanding sex-related differences in affective states, emotion and cognition. PMID:25450956

  14. Longitudinal changes in computerized EEG and mental function of the aged: a nine-year follow-up study.

    PubMed

    Nakano, T; Miyasaka, M; Ohtaka, T; Ohmori, K

    1992-01-01

    Computer-analyzed EEG data and mental functions of the healthy aged (28 survivors and 20 nonsurvivors) were followed for nine years in a study of their relationship with age and longevity. The study revealed that decrease in fast waves occurred from early senescence. The slowing of EEG, the increase in theta waves, and the decrease in alpha frequency became obvious in late senescence, after the late 70s or beyond 80 years. The amount of alpha waves was maintained until the early 80s. The decline of mental functions occurred with the slowing of EEG in late senescence. The slowing of EEG and the lowered scores of psychometrics were closely related to the longevity of life, comparing the survivors and nonsurvivors in retrospect. PMID:1391675

  15. Distinguishing Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion from Prolonged Febrile Seizures by Acute Phase EEG Spectrum Analysis

    PubMed Central

    Oguri, Masayoshi; Saito, Yoshiaki; Fukuda, Chisako; Kishi, Kazuko; Yokoyama, Atsushi; Lee, Sooyoung; Torisu, Hiroyuki; Toyoshima, Mitsuo; Sejima, Hitoshi; Kaji, Shunsaku; Hamano, Shin-ichiro; Okanishi, Toru; Tomita, Yutaka; Maegaki, Yoshihiro

    2016-01-01

    Background To differentiate the features of electroencephalography (EEG) after status epileptics in febrile children with final diagnosis of either febrile seizure (FS) or acute encephalopathy for an early diagnosis. Methods We retrospectively collected data from 68 children who had status epilepticus and for whom EEGs were recorded within 120 h. These included subjects with a final diagnosis of FS (n = 20), epileptic status (ES; n = 11), acute encephalopathy with biphasic seizures and late reduced diffusion (AESD; n = 18), mild encephalopathy with a reversible splenial lesion (MERS; n = 7), other febrile encephalopathies (n = 10), hypoxic-ischemic encephalopathy (n = 1), and intracranial bleeding (n = 1). Initially, all EEGs were visually assessed and graded, and correlation with outcome was explored. Representative EEG epochs were then selected for quantitative analyses. Furthermore, data from AESD (n = 7) and FS (n = 16) patients for whom EEG was recorded within 24 h were also compared. Results Although milder and most severe grades of EEG correlated with neurological outcome, the outcome of moderate EEG severity group was variable and was not predictable from usual inspection. Frequency band analysis revealed that solid delta power was not significantly different among the five groups (AESD, MERS, FS, ES and control), and that MERS group showed the highest theta band power. The ratios of delta/alpha and (delta + theta)/(alpha + beta) band powers were significantly higher in the AESD group than in other groups. The alpha and beta band powers in EEGs within 24 h from onset were significantly lower in the AESD group. The band powers and their ratios showed earlier improvement towards 24 h in FS than in AESD. Conclusion Sequential EEG recording up to 24 h from onset appeared to be helpful for distinction of AESD from FS before emergence of the second phase of AESD. PMID:27046946

  16. Electroencephalograph (EEG) study on self-contemplating image formation

    NASA Astrophysics Data System (ADS)

    Meng, Qinglei; Hong, Elliot; Choa, Fow-Sen

    2016-05-01

    Electroencephalography (EEG) is one of the most widely used electrophysiological monitoring methods and plays a significant role in studies of human brain electrical activities. Default mode network (DMN), is a functional connection of brain regions that are activated while subjects are not in task positive state or not focused on the outside world. In this study, EEG was used for human brain signals recording while all subjects were asked to sit down quietly on a chair with eyes closed and thinking about some parts of their own body, such as left and right hands, left and right ears, lips, nose, and the images of faces that they were familiar with as well as doing some simple mathematical calculation. The time is marker when the image is formed in the subject's mind. By analyzing brain activity maps 300ms right before the time marked instant for each of the 4 wave bands, Delta, Theta, Alpha and Beta waves. We found that for most EEG datasets during this 300ms, Delta wave activity would mostly locate at the frontal lobe or the visual cortex, and the change and movement of activities are slow. Theta wave activity tended to rotate along the edge of cortex either clockwise or counterclockwise. Beta wave behaved like inquiry types of oscillations between any two regions spread over the cortex. Alpha wave activity looks like a mix of the Theta and Beta activities but more close to Theta activity. From the observation we feel that Beta and high Alpha are playing utility role for information inquiry. Theta and low Alpha are likely playing the role of binding and imagination formation in DMN operations.

  17. Low-cost EEG-based sleep detection.

    PubMed

    Van Hal, Bryan; Rhodes, Samhita; Dunne, Bruce; Bossemeyer, Robert

    2014-01-01

    A real-time stage 1 sleep detection system using a low-cost single dry-sensor EEG headset is described. This device issues an auditory warning at the onset of stage 1 sleep using the "NeuroSky Mindset," an inexpensive commercial entertainment-based headset. The EEG signal is filtered into low/high alpha and low/high beta frequency bands which are analyzed to indicate the onset of sleep. Preliminary results indicate an 81% effective rate of detecting sleep with all failures being false positives of sleep onset. This device was able to predict and respond to the onset of drowsiness preceding stage 1 sleep allowing for earlier warnings with the result of fewer sleep-related accidents. PMID:25571009

  18. Neural activations during visual sequence learning leave a trace in post-training spontaneous EEG.

    PubMed

    Moisello, Clara; Meziane, Hadj Boumediene; Kelly, Simon; Perfetti, Bernardo; Kvint, Svetlana; Voutsinas, Nicholas; Blanco, Daniella; Quartarone, Angelo; Tononi, Giulio; Ghilardi, Maria Felice

    2013-01-01

    Recent EEG studies have shown that implicit learning involving specific cortical circuits results in an enduring local trace manifested as local changes in spectral power. Here we used a well characterized visual sequence learning task and high density-(hd-)EEG recording to determine whether also declarative learning leaves a post-task, local change in the resting state oscillatory activity in the areas involved in the learning process. Thus, we recorded hd-EEG in normal subjects before, during and after the acquisition of the order of a fixed spatial target sequence (VSEQ) and during the presentation of targets in random order (VRAN). We first determined the temporal evolution of spectral changes during VSEQ and compared it to VRAN. We found significant differences in the alpha and theta bands in three main scalp regions, a right occipito-parietal (ROP), an anterior-frontal (AFr), and a right frontal (RFr) area. The changes in frontal theta power during VSEQ were positively correlated with the learning rate. Further, post-learning EEG recordings during resting state revealed a significant increase in alpha power in ROP relative to a pre-learning baseline. We conclude that declarative learning is associated with alpha and theta changes in frontal and posterior regions that occur during the task, and with an increase of alpha power in the occipito-parietal region after the task. These post-task changes may represent a trace of learning and a hallmark of use-dependent plasticity. PMID:23799058

  19. Neural Activations during Visual Sequence Learning Leave a Trace in Post-Training Spontaneous EEG

    PubMed Central

    Moisello, Clara; Meziane, Hadj Boumediene; Kelly, Simon; Perfetti, Bernardo; Kvint, Svetlana; Voutsinas, Nicholas; Blanco, Daniella; Quartarone, Angelo; Tononi, Giulio; Ghilardi, Maria Felice

    2013-01-01

    Recent EEG studies have shown that implicit learning involving specific cortical circuits results in an enduring local trace manifested as local changes in spectral power. Here we used a well characterized visual sequence learning task and high density-(hd-)EEG recording to determine whether also declarative learning leaves a post-task, local change in the resting state oscillatory activity in the areas involved in the learning process. Thus, we recorded hd-EEG in normal subjects before, during and after the acquisition of the order of a fixed spatial target sequence (VSEQ) and during the presentation of targets in random order (VRAN). We first determined the temporal evolution of spectral changes during VSEQ and compared it to VRAN. We found significant differences in the alpha and theta bands in three main scalp regions, a right occipito-parietal (ROP), an anterior-frontal (AFr), and a right frontal (RFr) area. The changes in frontal theta power during VSEQ were positively correlated with the learning rate. Further, post-learning EEG recordings during resting state revealed a significant increase in alpha power in ROP relative to a pre-learning baseline. We conclude that declarative learning is associated with alpha and theta changes in frontal and posterior regions that occur during the task, and with an increase of alpha power in the occipito-parietal region after the task. These post-task changes may represent a trace of learning and a hallmark of use-dependent plasticity. PMID:23799058

  20. Lateralization of Auditory Language: An EEG Study of Bilingual Crow Indian Adolescents.

    ERIC Educational Resources Information Center

    Vocate, Donna R.

    A study was undertaken to learn whether involvement of the brain's right hemisphere in auditory language processing, a phenomenon found in a previous study of Crow-English bilinguals, was language-specific. Alpha blocking response as measured by electroencephalography (EEG) was used as an indicator of brain activity. It was predicted that (1)…

  1. [General Features of the Formation of EEG Wave Structure in Children and Adolescents Living in Northern European Russia].

    PubMed

    Soroko, S I; Bekshaev, S S; Rozhkov, V P; Nagornova, Zh V; Shemyakina, N V

    2015-01-01

    The article presents the results of the analysis of EEG wave structure formation in children and adolescents aged 7-18 years living under severe conditions of the North. The approaches developed in discrete mathematics (the graph theory, the theory of network flows) were used to assess the time-frequency transformations of EEG patterns. We evaluated conditional probabilities of reciprocal transitions between the components of six frequency bands of E EG (delta, theta, alpha-1, alpha-2, beta-1, beta-2). We described age- and sex-related features as well as regional specificities of the EEG wave structure. We defined the age periods of reorganization of diffuse EEG activities into the main EEG rhythms; the role of distinct rhythms in the maintenance of the EEG wave structure and its dynamic rearrangements was also discussed. The age-related changes of the structure of EEG patterns form some general picture of the morphofunctional development of brain in children and adolescents at different stages of postnatal ontogenesis under severe climate and socio-economic conditions of the North. PMID:26485790

  2. Changes in spontaneous EEG activity indicate a special kind of information processing in concept learning.

    PubMed

    Bösel, R; Mecklinger, A; Stolpe, R

    1990-12-01

    Some findings in the literature suggest that a high amount of spectral power in spontaneous EEG alpha 1 band (7.5-10.0 Hz) may be associated with tasks demanding extensive monitoring of stimulus information and combining features for a match with internal concepts ("exploration"). EEG recordings were obtained from 9 subjects involved in a concept-learning task. They had to match visually presented objects with a concept built up by hypothesis and to respond by pressing a "yes" or "no" key. Epochs of EEG data were analyzed with epoch center-times at 500 and 250 ms before response execution. In the case of "yes" responses, when subjects could match their hypothesis positively with combined features of the presented object increased alpha 1 spectral power was found. Also alpha 1 power was larger immediately after disconfirming feedback than after confirming feedback. Additionally, alpha 2 spectral power (10.5-12.5 Hz) was found to be larger 250 ms after confirming feedback than after disconfirming feedback. It is argued that alpha 1 power seems to reflect those mental processes which are involving in combining features and matching them to a concept in mind. The increase in alpha 2 power after confirming feedback is interpreted in terms of general processing demands imposed during task performance. PMID:2132682

  3. EEG oscillatory states as neuro-phenomenology of consciousness as revealed from patients in vegetative and minimally conscious states.

    PubMed

    Fingelkurts, Alexander A; Fingelkurts, Andrew A; Bagnato, Sergio; Boccagni, Cristina; Galardi, Giuseppe

    2012-03-01

    The value of resting electroencephalogram (EEG) in revealing neural constitutes of consciousness (NCC) was examined. We quantified the dynamic repertoire, duration and oscillatory type of EEG microstates in eyes-closed rest in relation to the degree of expression of clinical self-consciousness. For NCC a model was suggested that contrasted normal, severely disturbed state of consciousness and state without consciousness. Patients with disorders of consciousness were used. Results suggested that the repertoire, duration and oscillatory type of EEG microstates in resting condition quantitatively related to the level of consciousness expression in brain-damaged patients and healthy-conscious subjects. Specifically, results demonstrated that (a) decreased number of EEG microstate types was associated with altered states of consciousness, (b) unawareness was associated with the lack of diversity in EEG alpha-rhythmic microstates, and (c) the probability for the occurrence and duration of delta-, theta- and slow-alpha-rhythmic microstates were associated with unawareness, whereas the probability for the occurrence and duration of fast-alpha-rhythmic microstates were associated with consciousness. In conclusion, resting EEG has a potential value in revealing NCC. This work may have implications for clinical care and medical-legal decisions in patients with disorders of consciousness. PMID:22054641

  4. Discrete Scale Invariance of Human Large EEG Voltage Deflections is More Prominent in Waking than Sleep Stage 2.

    PubMed

    Zorick, Todd; Mandelkern, Mark A

    2015-01-01

    Electroencephalography (EEG) is typically viewed through the lens of spectral analysis. Recently, multiple lines of evidence have demonstrated that the underlying neuronal dynamics are characterized by scale-free avalanches. These results suggest that techniques from statistical physics may be used to analyze EEG signals. We utilized a publicly available database of fourteen subjects with waking and sleep stage 2 EEG tracings per subject, and observe that power-law dynamics of critical-state neuronal avalanches are not sufficient to fully describe essential features of EEG signals. We hypothesized that this could reflect the phenomenon of discrete scale invariance (DSI) in EEG large voltage deflections (LVDs) as being more prominent in waking consciousness. We isolated LVDs, and analyzed logarithmically transformed LVD size probability density functions (PDF) to assess for DSI. We find evidence of increased DSI in waking, as opposed to sleep stage 2 consciousness. We also show that the signatures of DSI are specific for EEG LVDs, and not a general feature of fractal simulations with similar statistical properties to EEG. Removing only LVDs from waking EEG produces a reduction in power in the alpha and beta frequency bands. These findings may represent a new insight into the understanding of the cortical dynamics underlying consciousness. PMID:26696860

  5. Discrete Scale Invariance of Human Large EEG Voltage Deflections is More Prominent in Waking than Sleep Stage 2

    PubMed Central

    Zorick, Todd; Mandelkern, Mark A.

    2015-01-01

    Electroencephalography (EEG) is typically viewed through the lens of spectral analysis. Recently, multiple lines of evidence have demonstrated that the underlying neuronal dynamics are characterized by scale-free avalanches. These results suggest that techniques from statistical physics may be used to analyze EEG signals. We utilized a publicly available database of fourteen subjects with waking and sleep stage 2 EEG tracings per subject, and observe that power-law dynamics of critical-state neuronal avalanches are not sufficient to fully describe essential features of EEG signals. We hypothesized that this could reflect the phenomenon of discrete scale invariance (DSI) in EEG large voltage deflections (LVDs) as being more prominent in waking consciousness. We isolated LVDs, and analyzed logarithmically transformed LVD size probability density functions (PDF) to assess for DSI. We find evidence of increased DSI in waking, as opposed to sleep stage 2 consciousness. We also show that the signatures of DSI are specific for EEG LVDs, and not a general feature of fractal simulations with similar statistical properties to EEG. Removing only LVDs from waking EEG produces a reduction in power in the alpha and beta frequency bands. These findings may represent a new insight into the understanding of the cortical dynamics underlying consciousness. PMID:26696860

  6. EEG signal analysis: a survey.

    PubMed

    Subha, D Puthankattil; Joseph, Paul K; Acharya U, Rajendra; Lim, Choo Min

    2010-04-01

    The EEG (Electroencephalogram) signal indicates the electrical activity of the brain. They are highly random in nature and may contain useful information about the brain state. However, it is very difficult to get useful information from these signals directly in the time domain just by observing them. They are basically non-linear and nonstationary in nature. Hence, important features can be extracted for the diagnosis of different diseases using advanced signal processing techniques. In this paper the effect of different events on the EEG signal, and different signal processing methods used to extract the hidden information from the signal are discussed in detail. Linear, Frequency domain, time - frequency and non-linear techniques like correlation dimension (CD), largest Lyapunov exponent (LLE), Hurst exponent (H), different entropies, fractal dimension(FD), Higher Order Spectra (HOS), phase space plots and recurrence plots are discussed in detail using a typical normal EEG signal. PMID:20433058

  7. Engagement Assessment Using EEG Signals

    NASA Technical Reports Server (NTRS)

    Li, Feng; Li, Jiang; McKenzie, Frederic; Zhang, Guangfan; Wang, Wei; Pepe, Aaron; Xu, Roger; Schnell, Thomas; Anderson, Nick; Heitkamp, Dean

    2012-01-01

    In this paper, we present methods to analyze and improve an EEG-based engagement assessment approach, consisting of data preprocessing, feature extraction and engagement state classification. During data preprocessing, spikes, baseline drift and saturation caused by recording devices in EEG signals are identified and eliminated, and a wavelet based method is utilized to remove ocular and muscular artifacts in the EEG recordings. In feature extraction, power spectrum densities with 1 Hz bin are calculated as features, and these features are analyzed using the Fisher score and the one way ANOVA method. In the classification step, a committee classifier is trained based on the extracted features to assess engagement status. Finally, experiment results showed that there exist significant differences in the extracted features among different subjects, and we have implemented a feature normalization procedure to mitigate the differences and significantly improved the engagement assessment performance.

  8. Human brain networks in physiological aging: a graph theoretical analysis of cortical connectivity from EEG data.

    PubMed

    Vecchio, Fabrizio; Miraglia, Francesca; Bramanti, Placido; Rossini, Paolo Maria

    2014-01-01

    Modern analysis of electroencephalographic (EEG) rhythms provides information on dynamic brain connectivity. To test the hypothesis that aging processes modulate the brain connectivity network, EEG recording was conducted on 113 healthy volunteers. They were divided into three groups in accordance with their ages: 36 Young (15-45 years), 46 Adult (50-70 years), and 31 Elderly (>70 years). To evaluate the stability of the investigated parameters, a subgroup of 10 subjects underwent a second EEG recording two weeks later. Graph theory functions were applied to the undirected and weighted networks obtained by the lagged linear coherence evaluated by eLORETA on cortical sources. EEG frequency bands of interest were: delta (2-4 Hz), theta (4-8 Hz), alpha1 (8-10.5 Hz), alpha2 (10.5-13 Hz), beta1 (13-20 Hz), beta2 (20-30 Hz), and gamma (30-40 Hz). The spectral connectivity analysis of cortical sources showed that the normalized Characteristic Path Length (λ) presented the pattern Young > Adult>Elderly in the higher alpha band. Elderly also showed a greater increase in delta and theta bands than Young. The correlation between age and λ showed that higher ages corresponded to higher λ in delta and theta and lower in the alpha2 band; this pattern reflects the age-related modulation of higher (alpha) and decreased (delta) connectivity. The Normalized Clustering coefficient (γ) and small-world network modeling (σ) showed non-significant age-modulation. Evidence from the present study suggests that graph theory can aid in the analysis of connectivity patterns estimated from EEG and can facilitate the study of the physiological and pathological brain aging features of functional connectivity networks. PMID:24820018

  9. Detection of EEG-resting state independent networks by eLORETA-ICA method

    PubMed Central

    Aoki, Yasunori; Ishii, Ryouhei; Pascual-Marqui, Roberto D.; Canuet, Leonides; Ikeda, Shunichiro; Hata, Masahiro; Imajo, Kaoru; Matsuzaki, Haruyasu; Musha, Toshimitsu; Asada, Takashi; Iwase, Masao; Takeda, Masatoshi

    2015-01-01

    Recent functional magnetic resonance imaging (fMRI) studies have shown that functional networks can be extracted even from resting state data, the so called “Resting State independent Networks” (RS-independent-Ns) by applying independent component analysis (ICA). However, compared to fMRI, electroencephalography (EEG) and magnetoencephalography (MEG) have much higher temporal resolution and provide a direct estimation of cortical activity. To date, MEG studies have applied ICA for separate frequency bands only, disregarding cross-frequency couplings. In this study, we aimed to detect EEG-RS-independent-Ns and their interactions in all frequency bands. We applied exact low resolution brain electromagnetic tomography-ICA (eLORETA-ICA) to resting-state EEG data in 80 healthy subjects using five frequency bands (delta, theta, alpha, beta and gamma band) and found five RS-independent-Ns in alpha, beta and gamma frequency bands. Next, taking into account previous neuroimaging findings, five RS-independent-Ns were identified: (1) the visual network in alpha frequency band, (2) dual-process of visual perception network, characterized by a negative correlation between the right ventral visual pathway (VVP) in alpha and beta frequency bands and left posterior dorsal visual pathway (DVP) in alpha frequency band, (3) self-referential processing network, characterized by a negative correlation between the medial prefrontal cortex (mPFC) in beta frequency band and right temporoparietal junction (TPJ) in alpha frequency band, (4) dual-process of memory perception network, functionally related to a negative correlation between the left VVP and the precuneus in alpha frequency band; and (5) sensorimotor network in beta and gamma frequency bands. We selected eLORETA-ICA which has many advantages over the other network visualization methods and overall findings indicate that eLORETA-ICA with EEG data can identify five RS-independent-Ns in their intrinsic frequency bands, and

  10. Methodological Conditions of Congruent Factors: A Comparison of EEG Frequency Structure Between Hemispheres.

    PubMed

    Andresen, B; Stemmler, G; Thom, E; Irrgang, E

    1984-01-01

    A study was conducted to examine congruence relations of EEG frequency factors between hemispheres. The central questions were aimed at procedural details of the factoring process which have the greatest "destructive" influence on congruence of factor patterns. On the basis of serially-rotated oblique solutions and evaluative simple structure criteria, two methodological results are reported: (a) the original principal components of two lead placements show a marked departure from an ideal congruence pattern, but can be forced into high congruence beyond 0.90 for the first twelve components by orthogonal procrustes rotation; (b) after this matching of principal components the expected optimum of congruence is only achieved in rotated solutions showing an optimal simple structure in terms of the Index of Factorial Simplicity (Kaiser, 1974). Additionally, the study leads to two substantive electroencephalographic results; (c) the factorial frequency structure of spontaneous EEG from two homologous positions (C3, C4) of the hemispheres is highly congruent. Thus, an identical measurement rationale for EEG frequency bands can be justified in asymmetry research; (d) the spectral dimensions of the alpha region show good correspondence to a recently published synoptic model of factor analytically defined EEG bands (Andresen, Thom, Irrgang, & Stemmler, 1982). The weight system of the three alpha components in this model can be recommended for psychophysiologically oriented EEG research. PMID:26776065

  11. Blind estimation of channel parameters and source components for EEG signals: a sparse factorization approach.

    PubMed

    Li, Yuanqing; Cichocki, Andrzej; Amari, Shun-Ichi

    2006-03-01

    In this paper, we use a two-stage sparse factorization approach for blindly estimating the channel parameters and then estimating source components for electroencephalogram (EEG) signals. EEG signals are assumed to be linear mixtures of source components, artifacts, etc. Therefore, a raw EEG data matrix can be factored into the product of two matrices, one of which represents the mixing matrix and the other the source component matrix. Furthermore, the components are sparse in the time-frequency domain, i.e., the factorization is a sparse factorization in the time frequency domain. It is a challenging task to estimate the mixing matrix. Our extensive analysis and computational results, which were based on many sets of EEG data, not only provide firm evidences supporting the above assumption, but also prompt us to propose a new algorithm for estimating the mixing matrix. After the mixing matrix is estimated, the source components are estimated in the time frequency domain using a linear programming method. In an example of the potential applications of our approach, we analyzed the EEG data that was obtained from a modified Sternberg memory experiment. Two almost uncorrelated components obtained by applying the sparse factorization method were selected for phase synchronization analysis. Several interesting findings were obtained, especially that memory-related synchronization and desynchronization appear in the alpha band, and that the strength of alpha band synchronization is related to memory performance. PMID:16566469

  12. The EEG as an index of neuromodulator balance in memory and mental illness

    PubMed Central

    Vakalopoulos, Costa

    2014-01-01

    There is a strong correlation between signature EEG frequency patterns and the relative levels of distinct neuromodulators. These associations become particularly evident during the sleep-wake cycle. The monoamine-acetylcholine balance hypothesis is a theory of neurophysiological markers of the EEG and a detailed description of the findings that support this proposal are presented in this paper. According to this model alpha rhythm reflects the relative predominance of cholinergic muscarinic signals and delta rhythm that of monoaminergic receptor effects. Both high voltage synchronized rhythms are likely mediated by inhibitory Gαi/o-mediated transduction of inhibitory interneurons. Cognitively, alpha and delta EEG measures are proposed to indicate automatic and flexible strategies, respectively. Sleep is associated with marked changes in relative neuromodulator levels corresponding to EEG markers of distinct stages. Sleep studies on memory consolidation present some of the strongest evidence yet for the respective roles of monoaminergic and cholinergic projections in declarative and non-declarative memory processes, a key theoretical premise for understanding the data. Affective dysregulation is reflected in altered EEG patterns during sleep. PMID:24782698

  13. Use of EEG to track visual attention in two dimensions

    NASA Astrophysics Data System (ADS)

    Coleman, Robert Alan

    This thesis investigates the use of EEG to track the spatial locus of covert, visual attention. Three experiments are described that were to detect the position of visual attention as it was deployed towards targets as they appeared. The first experiment uses flickering fields placed in the periphery of the visual field to induce SSVEPs, to be used to track the position of attention which varies horizontally between them. The flickers failed to produce significant SSVEP activity. However attention locus could still able to be tracked by endogenous lateralizations of 12Hz and 18Hz activity. A second experiment was then designed to track attention locus as it varied either horizontally or vertically using only endogenous EEG activity in the alpha (10Hz), low-beta (18Hz), high-beta (24Hz) and gamma (36Hz) bands. Tracking proved successful in all but a small number of subjects. Horizontally varying attention was associated with lateralizations of the alpha band and low-beta band, while vertically varying attention was associated with varying alpha band and low-beta band activity in the occipito-parietal junction over the central sulcus. A third experiment was then performed to track attention locus as it varied in two dimensions. Using a combination of the features found to be informative in the second experiment, tracking proved successful in up to nine bins of two-dimensional visual space. Tracking in either the horizontal or vertical dimension was also successful when attention varied in two dimensions. The success of this method shows that EEG can be used to passively detect the spatial position of attention, at varying degrees of position, as a person attends to objects they see.

  14. Discovering frequency sensitive thalamic nuclei from EEG microstate informed resting state fMRI.

    PubMed

    Schwab, Simon; Koenig, Thomas; Morishima, Yosuke; Dierks, Thomas; Federspiel, Andrea; Jann, Kay

    2015-09-01

    Microstates (MS), the fingerprints of the momentarily and time-varying states of the brain derived from electroencephalography (EEG), are associated with the resting state networks (RSNs). However, using MS fluctuations along different EEG frequency bands to model the functional MRI (fMRI) signal has not been investigated so far, or elucidated the role of the thalamus as a fundamental gateway and a putative key structure in cortical functional networks. Therefore, in the current study, we used MS predictors in standard frequency bands to predict blood oxygenation level dependent (BOLD) signal fluctuations. We discovered that multivariate modeling of BOLD-fMRI using six EEG-MS classes in eight frequency bands strongly correlated with thalamic areas and large-scale cortical networks. Thalamic nuclei exhibited distinct patterns of correlations for individual MS that were associated with specific EEG frequency bands. Anterior and ventral thalamic nuclei were sensitive to the beta frequency band, medial nuclei were sensitive to both alpha and beta frequency bands, and posterior nuclei such as the pulvinar were sensitive to delta and theta frequency bands. These results demonstrate that EEG-MS informed fMRI can elucidate thalamic activity not directly observable by EEG, which may be highly relevant to understand the rapid formation of thalamocortical networks. PMID:26052082

  15. Can arousing feedback rectify lapses in driving? Prediction from EEG power spectra

    NASA Astrophysics Data System (ADS)

    Lin, Chin-Teng; Huang, Kuan-Chih; Chuang, Chun-Hsiang; Ko, Li-Wei; Jung, Tzyy-Ping

    2013-10-01

    Objective. This study explores the neurophysiological changes, measured using an electroencephalogram (EEG), in response to an arousing warning signal delivered to drowsy drivers, and predicts the efficacy of the feedback based on changes in the EEG. Approach. Eleven healthy subjects participated in sustained-attention driving experiments. The driving task required participants to maintain their cruising position and compensate for randomly induced lane deviations using the steering wheel, while their EEG and driving performance were continuously monitored. The arousing warning signal was delivered to participants who experienced momentary behavioral lapses, failing to respond rapidly to lane-departure events (specifically the reaction time exceeded three times the alert reaction time). Main results. The results of our previous studies revealed that arousing feedback immediately reversed deteriorating driving performance, which was accompanied by concurrent EEG theta- and alpha-power suppression in the bilateral occipital areas. This study further proposes a feedback efficacy assessment system to accurately estimate the efficacy of arousing warning signals delivered to drowsy participants by monitoring the changes in their EEG power spectra immediately thereafter. The classification accuracy was up 77.8% for determining the need for triggering additional warning signals. Significance. The findings of this study, in conjunction with previous studies on EEG correlates of behavioral lapses, might lead to a practical closed-loop system to predict, monitor and rectify behavioral lapses of human operators in attention-critical settings.

  16. The effects of Dalmane /flurazepam hydrochloride/ on human EEG characteristics.

    NASA Technical Reports Server (NTRS)

    Frost, J. D., Jr.; Carrie, J. R. G.; Borda, R. P.; Kellaway, P.

    1973-01-01

    Evaluation of the changes in the waking EEGs of six healthy male subjects who received 30 mg daily oral doses of flurazepam hydrochloride for two weeks. A placebo was then substituted for flurazepam for another two weeks. An increase in beta activity with a maximum in fronto-central leads was observed during the test period. A small increase in the mean wavelength of the alpha and theta activities in the central-occipital derivations was also apparent in the subjects during the period.

  17. Alpha-thalassaemia.

    PubMed

    Harteveld, Cornelis L; Higgs, Douglas R

    2010-01-01

    Alpha-thalassaemia is inherited as an autosomal recessive disorder characterised by a microcytic hypochromic anaemia, and a clinical phenotype varying from almost asymptomatic to a lethal haemolytic anaemia.It is probably the most common monogenic gene disorder in the world and is especially frequent in Mediterranean countries, South-East Asia, Africa, the Middle East and in the Indian subcontinent. During the last few decades the incidence of alpha thalassaemia in North-European countries and Northern America has increased because of demographic changes. Compound heterozygotes and some homozygotes have a moderate to severe form of alpha thalassaemia called HbH disease. Hb Bart's hydrops foetalis is a lethal form in which no alpha-globin is synthesized. Alpha thalassaemia most frequently results from deletion of one or both alpha genes from the chromosome and can be classified according to its genotype/phenotype correlation. The normal complement of four functional alpha-globin genes may be decreased by 1, 2, 3 or all 4 copies of the genes, explaining the clinical variation and increasing severity of the disease. All affected individuals have a variable degree of anaemia (low Hb), reduced mean corpuscular haemoglobin (MCH/pg), reduced mean corpuscular volume (MCV/fl) and a normal/slightly reduced level of HbA2. Molecular analysis is usually required to confirm the haematological observations (especially in silent alpha-thalassaemia and alpha-thalassaemia trait). The predominant features in HbH disease are anaemia with variable amounts of HbH (0.8-40%). The type of mutation influences the clinical severity of HbH disease. The distinguishing features of the haemoglobin Bart's hydrops foetalis syndrome are the presence of Hb Bart's and the total absence of HbF. The mode of transmission of alpha thalassaemia is autosomal recessive. Genetic counselling is offered to couples at risk for HbH disease or haemoglobin Bart's Hydrops Foetalis Syndrome. Carriers of alpha+- or

  18. Brain oscillatory activity during motor imagery in EEG-fMRI coregistration.

    PubMed

    Formaggio, Emanuela; Storti, Silvia Francesca; Cerini, Roberto; Fiaschi, Antonio; Manganotti, Paolo

    2010-12-01

    The purpose of the present work was to investigate the correlation between topographical changes in brain oscillatory activity and the blood oxygenation level-dependent (BOLD) signal during a motor imagery (MI) task using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) coregistration. EEG was recorded in 7 healthy subjects inside a 1.5 T MR scanner during the imagination of the kinesthetic experience of movement. A Fast Fourier Transform was applied to EEG signal in the rest and active conditions. We used the event-related-synchronization (ERS)/desynchronization (ERD) approach to characterize where the imagination of movement produces a decrease in alpha and beta power. The mean alpha map showed ERD decrease localized over the contralateral sensory motor area (SM1c) and a light desynchronization in the ipsilateral sensory motor area (SM1i); whereas the mean beta map showed ERD decrease over the supplementary motor area (SMA). fMRI showed significant activation in SMA, SM1c, SM1i. The correlation is negative in the contralateral side and positive in the ipsilateral side. Using combined EEG-fMRI signals we obtained useful new information on the description of the changes in oscillatory activity in alpha and beta bands during MI and on the investigation of the sites of BOLD activity as possible sources in generating these rhythms. By correlating BOLD and ERD/ERS we may identify more accurately which regions contribute to changes of the electrical response. PMID:20850237

  19. Effects of Manual Lymph Drainage of the Neck on EEG in Subjects with Psychological Stress

    PubMed Central

    Shim, Jung-Myo; Kim, Sung-Joong

    2014-01-01

    [Purpose] The present study investigated the effect of manual lymph drainage (MLD) of the neck on electroencephalography (EEG) in subjects with psychological stress. [Methods] Twenty-six subjects were randomly allocated to receive one 15-min session of either MLD or resting on a bed (control). [Results] Analysis of EEG in the MLD group showed a significant increase in relaxation, manifested as an increase in average absolute and relative delta and alpha activity. [Conclusion] It is suggested that MLD provides acute neural effects that increase relaxation in subjects with psychological stress. PMID:24567691

  20. Resting State EEG Hemispheric Power Asymmetry in Children with Dyslexia.

    PubMed

    Papagiannopoulou, Eleni A; Lagopoulos, Jim

    2016-01-01

    Dyslexia is a neurodevelopmental disorder estimated to affect between 4 and 7% of the population. It is often referred to as a learning disability and is characterized by deficits in the linguistic system. To better understand the neural underpinnings of dyslexia, we examined the electroencephalography (EEG) power spectra between pre-adolescents with dyslexia and neurotypical control children during eyes closed state. We reported the differences in spontaneous oscillatory activity of each major EEG band (delta, theta, alpha, and beta) adopting a global as well as in a region-by-region and hemispheric approach to elucidate whether there are changes in asymmetry in children with dyslexia compared to controls. We also examined the relationship between EEG power spectra and clinical variables. The findings of our study confirm the presence of an atypical linguistic network, evident in children with dyslexia. This abnormal network hallmarked by a dominance of theta activity suggests that these abnormalities are present prior to these children learning to read, thus implicating delayed maturation and abnormal hypoarousal mechanisms. PMID:26942169

  1. Childhood abuse and EEG source localization in crack cocaine dependence.

    PubMed

    Alper, Kenneth; Shah, Jaini; Howard, Bryant; Roy John, E; Prichep, Leslie S

    2013-07-30

    Fourteen subjects with histories of sexual and/or physical abuse in childhood and 13 matched control subjects were selected from a consecutive series of clients in residential treatment for crack cocaine dependence. Standardized low-resolution electromagnetic brain tomography (sLORETA) was used to estimate the source generators of the EEG in a cortical mask with voxel z-scores referenced to normative data at frequency intervals of 039 Hz, with nonparametric permutation to correct by randomization for the number of comparisons and the intercorrelations and variance of distribution of voxel values. Subjects with histories of abuse in childhood had significantly greater EEG power than controls in the theta frequency range (3.51-7.41 Hz), with greatest differences in the 3.90-Hz band distributed mainly in the parahippocampal, fusiform, lingual, posterior cingulate, and insular gyri. The groups did not differ significantly with regard to delta (1.56-3.12 Hz), alpha (7.81-12.48 Hz), beta (12.87-19.89 Hz), and gamma (20.28-35.10 Hz) frequency power. In excess, theta EEG power, a bandwidth of transactions among hippocampus and amygdala and paralimbic and visual association cortex, may be a correlate of childhood exposure to abuse. PMID:23693089

  2. Subtractive fuzzy classifier based driver distraction levels classification using EEG.

    PubMed

    Wali, Mousa Kadhim; Murugappan, Murugappan; Ahmad, Badlishah

    2013-09-01

    [Purpose] In earlier studies of driver distraction, researchers classified distraction into two levels (not distracted, and distracted). This study classified four levels of distraction (neutral, low, medium, high). [Subjects and Methods] Fifty Asian subjects (n=50, 43 males, 7 females), age range 20-35 years, who were free from any disease, participated in this study. Wireless EEG signals were recorded by 14 electrodes during four types of distraction stimuli (Global Position Systems (GPS), music player, short message service (SMS), and mental tasks). We derived the amplitude spectrum of three different frequency bands, theta, alpha, and beta of EEG. Then, based on fusion of discrete wavelet packet transforms and fast fourier transform yield, we extracted two features (power spectral density, spectral centroid frequency) of different wavelets (db4, db8, sym8, and coif5). Mean ± SD was calculated and analysis of variance (ANOVA) was performed. A fuzzy inference system classifier was applied to different wavelets using the two extracted features. [Results] The results indicate that the two features of sym8 posses highly significant discrimination across the four levels of distraction, and the best average accuracy achieved by the subtractive fuzzy classifier was 79.21% using the power spectral density feature extracted using the sym8 wavelet. [Conclusion] These findings suggest that EEG signals can be used to monitor distraction level intensity in order to alert drivers to high levels of distraction. PMID:24259914

  3. Resting State EEG Hemispheric Power Asymmetry in Children with Dyslexia

    PubMed Central

    Papagiannopoulou, Eleni A.; Lagopoulos, Jim

    2016-01-01

    Dyslexia is a neurodevelopmental disorder estimated to affect between 4 and 7% of the population. It is often referred to as a learning disability and is characterized by deficits in the linguistic system. To better understand the neural underpinnings of dyslexia, we examined the electroencephalography (EEG) power spectra between pre-adolescents with dyslexia and neurotypical control children during eyes closed state. We reported the differences in spontaneous oscillatory activity of each major EEG band (delta, theta, alpha, and beta) adopting a global as well as in a region-by-region and hemispheric approach to elucidate whether there are changes in asymmetry in children with dyslexia compared to controls. We also examined the relationship between EEG power spectra and clinical variables. The findings of our study confirm the presence of an atypical linguistic network, evident in children with dyslexia. This abnormal network hallmarked by a dominance of theta activity suggests that these abnormalities are present prior to these children learning to read, thus implicating delayed maturation and abnormal hypoarousal mechanisms. PMID:26942169

  4. EEG-microstate dependent emergence of perceptual awareness

    PubMed Central

    Britz, Juliane; Díaz Hernàndez, Laura; Ro, Tony; Michel, Christoph M.

    2014-01-01

    We investigated whether the differences in perceptual awareness for stimuli at the threshold of awareness can arise from different global brain states before stimulus onset indexed by the EEG microstate. We used a metacontrast backward masking paradigm in which subjects had to discriminate between two weak stimuli and obtained measures of accuracy and awareness while their EEG was recorded from 256 channels. Comparing targets that were correctly identified with and without awareness allowed us to contrast differences in awareness while keeping performance constant for identical physical stimuli. Two distinct pre-stimulus scalp potential fields (microstate maps) dissociated correct identification with and without awareness, and their estimated intracranial generators were stronger in primary visual cortex before correct identification without awareness. This difference in activity cannot be explained by differences in alpha power or phase which were less reliably linked with differential pre-stimulus activation of primary visual cortex. Our results shed a new light on the function of pre-stimulus activity in early visual cortex in visual awareness and emphasize the importance of trial-by-trials analysis of the spatial configuration of the scalp potential field identified with multichannel EEG. PMID:24860450

  5. EEG-MEG Integration Enhances the Characterization of Functional and Effective Connectivity in the Resting State Network

    PubMed Central

    Mideksa, Kidist Gebremariam; Anwar, Abdul Rauf; Stephani, Ulrich; Deuschl, Günther; Freitag, Christine M.; Siniatchkin, Michael

    2015-01-01

    At the sensor level many aspects, such as spectral power, functional and effective connectivity as well as relative-power-ratio ratio (RPR) and spatial resolution have been comprehensively investigated through both electroencephalography (EEG) and magnetoencephalography (MEG). Despite this, differences between both modalities have not yet been systematically studied by direct comparison. It remains an open question as to whether the integration of EEG and MEG data would improve the information obtained from the above mentioned parameters. Here, EEG (64-channel system) and MEG (275 sensor system) were recorded simultaneously in conditions with eyes open (EO) and eyes closed (EC) in 29 healthy adults. Spectral power, functional and effective connectivity, RPR, and spatial resolution were analyzed at five different frequency bands (delta, theta, alpha, beta and gamma). Networks of functional and effective connectivity were described using a spatial filter approach called the dynamic imaging of coherent sources (DICS) followed by the renormalized partial directed coherence (RPDC). Absolute mean power at the sensor level was significantly higher in EEG than in MEG data in both EO and EC conditions. At the source level, there was a trend towards a better performance of the combined EEG+MEG analysis compared with separate EEG or MEG analyses for the source mean power, functional correlation, effective connectivity for both EO and EC. The network of coherent sources and the spatial resolution were similar for both the EEG and MEG data if they were analyzed separately. Results indicate that the combined approach has several advantages over the separate analyses of both EEG and MEG. Moreover, by a direct comparison of EEG and MEG, EEG was characterized by significantly higher values in all measured parameters in both sensor and source level. All the above conclusions are specific to the resting state task and the specific analysis used in this study to have general

  6. Effects of nootropics on the EEG in conscious rats and their modification by glutamatergic inhibitors.

    PubMed

    Vorobyov, Vasily; Kaptsov, Vladimir; Kovalev, Georgy; Sengpiel, Frank

    2011-05-30

    To study the effects of acute and repeated injections of nootropics and to learn how glutamate receptors might be involved in their mediation, the frequency spectra of cortical and hippocampal electroencephalogram (EEG) were analyzed in non-narcotized rats subcutaneously injected repeatedly with Piracetam (400mg/kg) or its analogue, Noopept (0.2mg/kg), after intracerebroventricular infusions of saline (5 μl) or the antagonists of NMDA and quisqualate/AMPA receptors: CPP (0.1 nmol) and GDEE (1 μmol), respectively. Piracetam increased alpha/beta1 EEG activity in the left frontal cortex, and alpha activity in both the right cortex and hippocampus, with a 10-min latency and 40-min duration. Noopept increased alpha/beta1 activity, with 30-min latency and 40-min duration in all brain areas. CPP pretreatment eliminated Piracetam EEG effects; reduced Noopept effects in the cortex and completely suppressed them in the hippocampus. After four injections of Piracetam, EEG effects were very small in the cortex, and completely lacking in the hippocampus, while GDEE pretreatment partially recovered them. The effect of Noopept in the alpha/beta1 ranges was replaced by increased beta2 activity after the eighth injection, while no effects were observed after the ninth one. GDEE pretreatment restored the effect of Noopept in the beta2 frequency range. These results demonstrate similarities in EEG effects and their mediatory mechanisms for Piracetam and its much more effective analogue, Noopept. Activation of NMDA receptors is involved in the effects of a single injection of the nootropics, whereas activation of quisqualate/AMPA receptors is associated with the decrease in their efficacy after repeated use. PMID:21414388

  7. [Voluntary alpha-power increasing training impact on the heart rate variability].

    PubMed

    Bazanova, O M; Balioz, N V; Muravleva, K B; Skoraia, M V

    2013-01-01

    In order to study the effect of the alpha EEG power increasing training at heart rate variability (HRV) as the index of the autonomic regulation of cognitive functions there were follow tasks: (1) to figure out the impact of biofeedback in the voluntary increasing the power in the individual high-frequency alpha-band effect on heart rate variability and related characteristics of cognitive and emotional spheres, (2) to determine the nature of the relationship between alpha activity indices and heart rate variability, depending on the alpha-frequency EEG pattern at rest (3) to examine how the individual alpha frequency EEG pattern is reflected in changes HRV as a result of biofeedback training. Psychometric indicators of cognitive performance, the characteristics of the alpha-EEG activity and heart rate variability (HRV) as LF/HF and pNN50 were recorded in 27 healthy men aged 18-34 years, before, during, and after 10 sessions of training of voluntary increase in alpha power in the individual high-frequency alpha band with eyes closed. To determine the biofeedback effect on the alpha power increasing training, data subjects are compared in 2 groups: experimental (14) with the real and the control group (13 people)--with mock biofeedback. The follow up effect of trainings was studied through month over the 10 training sessions. Results showed that alpha biofeedback training enhanced the fluency and accuracy in cognitive performance, decreased anxiety and frontal EMG, increased resting frequency, width and power in individual upper alpha range only in participants with low baseline alpha frequency. While mock biofeedback increased resting alpha power only in participants with high baseline resting alpha frequency and did change neither cognitive performance, nor HRV indices. Biofeedback training eliminated the alpha power decrease in response to arithmetic task in both with high and low alpha frequency participants and this effect was followed up over the month. Mock

  8. Extraversion and the EEG: II. A test of Gale's hypothesis.

    PubMed

    O'Gorman, J G; Mallise, L R

    1984-09-01

    The study sought to test A. Gale's hypothesis that only under moderately arousing conditions will introverts be shown to differ from extraverts in EEG defined arousal. Alpha activity was recorded for 45 subjects under each of six conditions, and extravert and introvert groups formed on the basis of subject's score on the E scale of the Eysenck Personality Questionnaire (EPQ). Contrary to the hypothesis, extraverts showed more prestimulus alpha activity than introverts under all conditions except opening and closing eyes on instruction where the reverse was the case. It is argued that the failure to confirm the hypothesis is not due to faults in design or execution of the study, and that future research may profit more from ignoring interactions of the sort demonstrated. PMID:6518221

  9. Sleep misperception, EEG characteristics and autonomic nervous system activity in primary insomnia: a retrospective study on polysomnographic data.

    PubMed

    Maes, J; Verbraecken, J; Willemen, M; De Volder, I; van Gastel, A; Michiels, N; Verbeek, I; Vandekerckhove, M; Wuyts, J; Haex, B; Willemen, T; Exadaktylos, V; Bulckaert, A; Cluydts, R

    2014-03-01

    Misperception of Sleep Onset Latency, often found in Primary Insomnia, has been cited to be influenced by hyperarousal, reflected in EEG- and ECG-related indices. The aim of this retrospective study was to examine the association between Central Nervous System (i.e. EEG) and Autonomic Nervous System activity in the Sleep Onset Period and the first NREM sleep cycle in Primary Insomnia (n=17) and healthy controls (n=11). Furthermore, the study examined the influence of elevated EEG and Autonomic Nervous System activity on Stage2 sleep-protective mechanisms (K-complexes and sleep spindles). Confirming previous findings, the Primary Insomnia-group overestimated Sleep Onset Latency and this overestimation was correlated with elevated EEG activity. A higher amount of beta EEG activity during the Sleep Onset Period was correlated with the appearance of K-complexes immediately followed by a sleep spindle in the Primary Insomnia-group. This can be interpreted as an extra attempt to protect sleep continuity or as a failure of the sleep-protective role of the K-complex by fast EEG frequencies following within one second. The strong association found between K-alpha (K-complex within one second followed by 8-12 Hz EEG activity) in Stage2 sleep and a lower parasympathetic Autonomic Nervous System dominance (less high frequency HR) in Slow-wave sleep, further assumes a state of hyperarousal continuing through sleep in Primary Insomnia. PMID:24177246

  10. Improvements in quantitative EEG following consumption of a natural citicoline-enhanced beverage.

    PubMed

    Bruce, Steven E

    2012-06-01

    The present study examined the impact of a taurine-free drink enhanced with citicoline and other natural ingredients on electrophysiological markers of mental alertness. Ten healthy adult participants enrolled in a double-blind, placebo-controlled crossover study and were randomized to receive either placebo or the citicoline supplement on the first visit. Measures of electrical brain activity using electroencephalogram (EEG) were collected 30 min after consuming the beverage. Seven days after the initial assessment participants completed the alternative condition (placebo or citicoline beverage). Compared to placebo, significant improvements were found in frontal alpha EEG and N100 event related potentials (ERP) associated with the citicoline-enhanced supplement. These preliminary findings suggest that a novel brain drink containing compounds known to increase choline in the brain significantly improved attention as measured by ERP and EEG. These findings suggest that a viable and alternative brain supplement without potential compounds such as taurine may augment attentional mechanisms in healthy individuals. PMID:22578105

  11. Sound fields in biosphere of the mountain streams and their influence on the human EEG

    NASA Astrophysics Data System (ADS)

    Kasprzak, Cezary; Damijan, Zbigniew; Panuszka, Ryszard

    2001-05-01

    Low-frequency acoustics fields in the biosphere of the headwater regions in Poland (Bieszczady Mountains and Tatry Mountains) were researched and the the influence of observed low-frequency acoustics field on changes of human EEG signals was analyzed. Several places were found with specific distribution of sound fields where low frequencies dominated. Interesting parameters of distribution of the riverbeds and physical characterization of flows were determined. Standard EEG signal was recorded from subjects until exposure for 20 min. It was ascertained that spectra of sound-pressure levels were with specific shape, very similar for a group of rivers. The influences of SPL on level of power spectrum of EEG signal were analyzed. Changes in the brain waves were observed with increases in delta and decreases in alpha. Tested subjects reported behavior specific for relaxation.

  12. Eye contact reveals a relationship between Neuroticism and anterior EEG asymmetry.

    PubMed

    Uusberg, Helen; Allik, Jüri; Hietanen, Jari K

    2015-07-01

    Although anterior functional brain asymmetry has been linked to individual differences in affect and motivation, its relations with the Five Factor Model personality traits remain unclear. We investigated anterior EEG alpha-activity asymmetry in response to variable degrees of social contact induced by different gaze directions of a "live" model. Neuroticism was negatively related to the anterior EEG asymmetry scores in response to direct gaze, indicating that higher levels of Neuroticism were associated with avoidance-related, relative right-sided functional brain asymmetry. Neuroticism was also related to behavioral direct gaze avoidance and subjective averted gaze preference. These relationships arose primarily from the Withdrawal aspect factor, suggesting that two subdomains of Neuroticism may be differentially related to approach-avoidance tendencies. These findings demonstrate that experimental manipulations of social contact can reveal personality related differences in anterior EEG asymmetry responsiveness, offering a motivationally salient alternative to resting state measures. PMID:25980386

  13. An automatic detector of drowsiness based on spectral analysis and wavelet decomposition of EEG records.

    PubMed

    Garces Correa, Agustina; Laciar Leber, Eric

    2010-01-01

    An algorithm to detect automatically drowsiness episodes has been developed. It uses only one EEG channel to differentiate the stages of alertness and drowsiness. In this work the vectors features are building combining Power Spectral Density (PDS) and Wavelet Transform (WT). The feature extracted from the PSD of EEG signal are: Central frequency, the First Quartile Frequency, the Maximum Frequency, the Total Energy of the Spectrum, the Power of Theta and Alpha bands. In the Wavelet Domain, it was computed the number of Zero Crossing and the integrated from the scale 3, 4 and 5 of Daubechies 2 order WT. The classifying of epochs is being done with neural networks. The detection results obtained with this technique are 86.5 % for drowsiness stages and 81.7% for alertness segment. Those results show that the features extracted and the classifier are able to identify drowsiness EEG segments. PMID:21096343

  14. Aesthetic preference recognition of 3D shapes using EEG.

    PubMed

    Chew, Lin Hou; Teo, Jason; Mountstephens, James

    2016-04-01

    Recognition and identification of aesthetic preference is indispensable in industrial design. Humans tend to pursue products with aesthetic values and make buying decisions based on their aesthetic preferences. The existence of neuromarketing is to understand consumer responses toward marketing stimuli by using imaging techniques and recognition of physiological parameters. Numerous studies have been done to understand the relationship between human, art and aesthetics. In this paper, we present a novel preference-based measurement of user aesthetics using electroencephalogram (EEG) signals for virtual 3D shapes with motion. The 3D shapes are designed to appear like bracelets, which is generated by using the Gielis superformula. EEG signals were collected by using a medical grade device, the B-Alert X10 from advance brain monitoring, with a sampling frequency of 256 Hz and resolution of 16 bits. The signals obtained when viewing 3D bracelet shapes were decomposed into alpha, beta, theta, gamma and delta rhythm by using time-frequency analysis, then classified into two classes, namely like and dislike by using support vector machines and K-nearest neighbors (KNN) classifiers respectively. Classification accuracy of up to 80 % was obtained by using KNN with the alpha, theta and delta rhythms as the features extracted from frontal channels, Fz, F3 and F4 to classify two classes, like and dislike. PMID:27066153

  15. On the Individuality of Sleep EEG Spectra

    PubMed Central

    Lewandowski, Achim; Rosipal, Roman; Dorffner, Georg

    2013-01-01

    Research in recent years has supported the hypothesis that many properties of the electroencephalogram (EEG) are specific to an individual. In this study, the intra- and inter-individual variations of sleep EEG signals were investigated. This was carried out by analyzing the stability of the average EEG spectra individually computed for the Rechtschaffen and Kales (RK) sleep stages. Six EEG channels were used to account for the topographical aspect of the analysis. Validity of the results was supported by considering a wide dataset of 174 subjects with normal sleep. Subjects spent two consecutive nights in the sleep laboratory during which EEG recordings were obtained. High similarity between average spectra of two consecutive nights was found considering an individual. More than 89% of the second night recordings were correctly assigned to their counterparts of the first night. The average spectra of sleep EEG computed for each RK sleep stage have shown a high degree of individuality. PMID:23997385

  16. Effects of inhalation of essential oils on EEG activity and sensory evaluation.

    PubMed

    Masago, R; Matsuda, T; Kikuchi, Y; Miyazaki, Y; Iwanaga, K; Harada, H; Katsuura, T

    2000-01-01

    The purpose of this study was to investigate EEG changes in subjects directly after inhalation of essential oils, and subsequently, to observe any effect on subjective evaluations. EEG and sensory evaluation were assessed in 13 healthy female subjects in four odor conditions. Four odor conditions (including lavender, chamomile, sandalwood and eugenol) were applied respectively for each subject in the experiment. The results were as follows. 1) Four basic factors were extracted from 22 adjective pairs by factor analysis of the sensory evaluation. The first factor was "comfortable feeling", the second "cheerful feeling", the third "natural feeling" and the fourth "feminine feeling". In the score of the first factor (comfortable feeling), the odors in order of high contribution are lavender, eugenol, chamomile and sandalwood. 2) Alpha 1 (8-10 Hz) of EEG at parietal and posterior temporal regions significantly decreased soon after the onset of inhalation of lavender oil (p < 0.01). Significant changes of alpha 1 were also observed after inhalation of eugenol or chamomile. The change after inhalation of sandalwood was not significant. These results showed that alpha 1 activity significantly decreased under odor conditions in which subjects felt comfortable, and showed no significant change under odor conditions in which subjects felt uncomfortable. These results suggest a possible correlation between alpha 1 activity and subjective evaluation. PMID:10979248

  17. Age effects on EEG correlates of the Wisconsin Card Sorting Test

    PubMed Central

    Dias, Nuno S; Ferreira, Daniela; Reis, Joana; Jacinto, Luís R; Fernandes, Luís; Pinho, Francisco; Festa, Joana; Pereira, Mariana; Afonso, Nuno; Santos, Nadine C; Cerqueira, João J; Sousa, Nuno

    2015-01-01

    Body and brain undergo several changes with aging. One of the domains in which these changes are more remarkable relates with cognitive performance. In the present work, electroencephalogram (EEG) markers (power spectral density and spectral coherence) of age-related cognitive decline were sought whilst the subjects performed the Wisconsin Card Sorting Test (WCST). Considering the expected age-related cognitive deficits, WCST was applied to young, mid-age and elderly participants, and the theta and alpha frequency bands were analyzed. From the results herein presented, higher theta and alpha power were found to be associated with a good performance in the WCST of younger subjects. Additionally, higher theta and alpha coherence were also associated with good performance and were shown to decline with age and a decrease in alpha peak frequency seems to be associated with aging. Additionally, inter-hemispheric long-range coherences and parietal theta power were identified as age-independent EEG correlates of cognitive performance. In summary, these data reveals age-dependent as well as age-independent EEG correlates of cognitive performance that contribute to the understanding of brain aging and related cognitive deficits. PMID:26216431

  18. Quantitative EEG is an objective, sensitive, and reliable indicator of transient anesthetic effects during Wada tests.

    PubMed

    Tu, Bin; Assassi, Nadege J; Bazil, Carl W; Hamberger, Marla J; Hirsch, Lawrence J

    2015-04-01

    The intracarotid amobarbital or Wada procedure is a component of the presurgical evaluation for refractory epilepsy, during which monitoring the onset and offset of transient anesthetic effects is critical. In this study, the authors characterized changes of 8 quantitative measures during 26 Wada tests, which included alpha, beta, theta, and delta powers, alpha/delta power ratio, beta/delta power ratio, median amplitude-integrated EEG, and 90% spectral edge frequency (SEF90), and correlated them with contralateral hemiplegia. The authors found that on the side of injection, delta and theta powers, alpha/delta power ratio, beta/delta power ratio, and SEF90 peaked within 1 minute after injection of 70 to 150 mg amobarbital or 4 to 7 mg methohexital. When contralateral arm strength returned to 3/5, delta power and amplitude-integrated EEG decayed on average 24% and 19%, respectively, for amobarbital, similar to that of methohexital (27% and 18%). Because delta power resolution most closely mirrored that of the hemiplegia and amplitude-integrated EEG had the highest signal/noise ratio, these quantitative values appear to be the best measures for decay of anesthetic effects. Increase in alpha power persisted longest, and therefore may be the best measure of late residual anesthetic effects. PMID:25580802

  19. Age-dependent electroencephalogram (EEG) patterns during sevoflurane general anesthesia in infants

    PubMed Central

    2015-01-01

    Electroencephalogram (EEG) approaches may provide important information about developmental changes in brain-state dynamics during general anesthesia. We used multi-electrode EEG, analyzed with multitaper spectral methods and video recording of body movement to characterize the spatio-temporal dynamics of brain activity in 36 infants 0–6 months old when awake, and during maintenance of and emergence from sevoflurane general anesthesia. During maintenance: (1) slow-delta oscillations were present in all ages; (2) theta and alpha oscillations emerged around 4 months; (3) unlike adults, all infants lacked frontal alpha predominance and coherence. Alpha power was greatest during maintenance, compared to awake and emergence in infants at 4–6 months. During emergence, theta and alpha power decreased with decreasing sevoflurane concentration in infants at 4–6 months. These EEG dynamic differences are likely due to developmental factors including regional differences in synaptogenesis, glucose metabolism, and myelination across the cortex. We demonstrate the need to apply age-adjusted analytic approaches to develop neurophysiologic-based strategies for pediatric anesthetic state monitoring. DOI: http://dx.doi.org/10.7554/eLife.06513.001 PMID:26102526

  20. Resting State EEG in Children With Learning Disabilities: An Independent Component Analysis Approach.

    PubMed

    Jäncke, Lutz; Alahmadi, Nsreen

    2016-01-01

    In this study, the neurophysiological underpinnings of learning disabilities (LD) in children are examined using resting state EEG. We were particularly interested in the neurophysiological differences between children with learning disabilities not otherwise specified (LD-NOS), learning disabilities with verbal disabilities (LD-Verbal), and healthy control (HC) children. We applied 2 different approaches to examine the differences between the different groups. First, we calculated theta/beta and theta/alpha ratios in order to quantify the relationship between slow and fast EEG oscillations. Second, we used a recently developed method for analyzing spectral EEG, namely the group independent component analysis (gICA) model. Using these measures, we identified substantial differences between LD and HC children and between LD-NOS and LD-Verbal children in terms of their spectral EEG profiles. We obtained the following findings: (a) theta/beta and theta/alpha ratios were substantially larger in LD than in HC children, with no difference between LD-NOS and LD-Verbal children; (b) there was substantial slowing of EEG oscillations, especially for gICs located in frontal scalp positions, with LD-NOS children demonstrating the strongest slowing; (c) the estimated intracortical sources of these gICs were mostly located in brain areas involved in the control of executive functions, attention, planning, and language; and (d) the LD-Verbal children demonstrated substantial differences in EEG oscillations compared with LD-NOS children, and these differences were localized in language-related brain areas. The general pattern of atypical neurophysiological activation found in LD children suggests that they suffer from neurophysiological dysfunction in brain areas involved with the control of attention, executive functions, planning, and language functions. LD-Verbal children also demonstrate atypical activation, especially in language-related brain areas. These atypical

  1. Modafinil Increases Awake EEG Activation and Improves Performance in Obstructive Sleep Apnea during Continuous Positive Airway Pressure Withdrawal

    PubMed Central

    Wang, David; Bai, Xiao Xue; Williams, Shaun C.; Hua, Shu Cheng; Kim, Jong-Won; Marshall, Nathaniel S.; D'Rozario, Angela; Grunstein, Ronald R.

    2015-01-01

    Objectives: We examined the changes in waking electroencephalography (EEG) biomarkers with modafinil during continuous positive airway pressure (CPAP) withdrawal in patients with obstructive sleep apnea (OSA) to investigate neurophysiological evidence for potential neurocognitive improvements. Design: Randomized double-blind placebo-controlled crossover study. CPAP was used for the first night and then withdrawn for 2 subsequent nights. Each morning after the 2 CPAP withdrawal nights, patients received either 200 mg modafinil or placebo. After a 5-w washout, the procedure repeated with the crossover drug. Setting: University teaching hospital. Participants: Stable CPAP users (n = 23 men with OSA) Measurement and Results: Karolinska Drowsiness Test (KDT) (awake EEG measurement with eyes open and closed), Psychomotor Vigilance Task (PVT), and driving simulator Performance were assessed bihourly during the 3 testing days following CPAP treatment and CPAP withdrawal nights. Compared to placebo, modafinil significantly increased awake EEG activation (faster EEG frequency) with increased alpha/delta (A/D) ratio (P < 0.0001) and fast ratio = (alpha+beta)/(delta+theta) (P < 0.0001) across the 2 days of CPAP withdrawal. The A/D ratio significantly correlated with the driving simulator response time (P = 0.015), steering variation (P = 0.002), and PVT reaction time (P = 0.006). In contrast, individual EEG band power of alpha, beta, theta, and delta did not correlate with any neurocognitive performance. Conclusions: Modafinil administration during continuous positive airway pressure (CPAP) withdrawal increased awake EEG activation, which correlated to improved performance. This study provides supporting neurophysiological evidence that modafinil is a potential short-term treatment option during acute CPAP withdrawal. Citation: Wang D, Bai XX, Williams SC, Hua SC, Kim JW, Marshall NS, D'Rozario A, Grunstein RR. Modafinil increases awake EEG activation and improves performance

  2. Applying support vector machine on hybrid fNIRS/EEG signal to classify driver's conditions (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Nguyen, Thien; Ahn, Sangtae; Jang, Hyojung; Jun, Sung C.; Kim, Jae G.

    2016-03-01

    Driver's condition plays a critical role in driving safety. The fact that about 20 percent of automobile accidents occurred due to driver fatigue leads to a demand for developing a method to monitor driver's status. In this study, we acquired brain signals such as oxy- and deoxyhemoglobin and neuronal electrical activity by a hybrid fNIRS/EEG system. Experiments were conducted with 11 subjects under two conditions: Normal condition, when subjects had enough sleep, and sleep deprivation condition, when subject did not sleep previous night. During experiment, subject performed a driving task with a car simulation system for 30 minutes. After experiment, oxy-hemoglobin and deoxy-hemoglobin changes were derived from fNIRS data, while beta and alpha band relative power were calculated from EEG data. Decrement of oxy-hemoglobin, beta band power, and increment of alpha band power were found in sleep deprivation condition compare to normal condition. These features were then applied to classify two conditions by Fisher's linear discriminant analysis (FLDA). The ratio of alpha-beta relative power showed classification accuracy with a range between 62% and 99% depending on a subject. However, utilization of both EEG and fNIRS features increased accuracy in the range between 68% and 100%. The highest increase of accuracy is from 63% using EEG to 99% using both EEG and fNIRS features. In conclusion, the enhancement of classification accuracy is shown by adding a feature from fNIRS to the feature from EEG using FLDA which provides the need of developing a hybrid fNIRS/EEG system.

  3. Estimation of the propagation direction and spectral properties of the EEG signals registered during sevoflurane anaesthesia using Directed Transfer Function method

    NASA Astrophysics Data System (ADS)

    Olejarczyk, Elzbieta; Kaminski, Maciej; Marciniak, Radoslaw; Byrczek, Tomasz; Stasiowski, Michal; Jalowiecki, Przemyslaw; Sobieszek, Aleksander; Zmyslowski, Wojciech

    2011-01-01

    The aim of this study was to estimate spectral properties and propagation of the EEG signals registered during sevoflurane anaesthesia between individual EEG recording channels. The intensities of activity flows were calculated for delta, theta, alpha and beta waves using the Directed Transfer Function integration procedure. It was found that delta waves played the dominant role in the EEG signal propagation during anesthesia and it was suggested that theta and alpha waves propagation could be related to the processes participating in the wakefulness control. Data obtained with DTF method were compared with data received from the analysis of cerebral blood flow with the use of PET in other laboratory. This study showed that analysis of the EEG signal propagation is useful for better understanding and thus safer induction of anaesthesia procedure.

  4. Alpha Particle

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Term that is sometimes used to describe a helium nucleus, a positively charged particle that consists of two protons and two neutrons, bound together. Alpha particles, which were discovered by Ernest Rutherford (1871-1937) in 1898, are emitted by atomic nuclei that are undergoing alpha radioactivity. During this process, an unstable heavy nucleus spontaneously emits an alpha particle and transmut...

  5. Tele-transmission of EEG recordings.

    PubMed

    Lemesle, M; Kubis, N; Sauleau, P; N'Guyen The Tich, S; Touzery-de Villepin, A

    2015-03-01

    EEG recordings can be sent for remote interpretation. This article aims to define the tele-EEG procedures and technical guidelines. Tele-EEG is a complete medical act that needs to be carried out with the same quality requirements as a local one in terms of indications, formulation of the medical request and medical interpretation. It adheres to the same quality requirements for its human resources and materials. It must be part of a medical organization (technical and medical network) and follow all rules and guidelines of good medical practices. The financial model of this organization must include costs related to performing the EEG recording, operating and maintenance of the tele-EEG network and medical fees of the physician interpreting the EEG recording. Implementing this organization must be detailed in a convention between all parties involved: physicians, management of the healthcare structure, and the company providing the tele-EEG service. This convention will set rules for network operation and finance, and also the continuous training of all staff members. The tele-EEG system must respect all rules for safety and confidentiality, and ensure the traceability and storing of all requests and reports. Under these conditions, tele-EEG can optimize the use of human resources and competencies in its zone of utilization and enhance the organization of care management. PMID:25703437

  6. Test-retest reliability of a single-channel, wireless EEG system.

    PubMed

    Rogers, Jeffrey M; Johnstone, Stuart J; Aminov, Anna; Donnelly, James; Wilson, Peter H

    2016-08-01

    Recording systems to acquire electroencephalogram (EEG) data are traditionally lab-based. However, there are shortcomings to this method, and the ease of use and portability of emerging wireless EEG technologies offer a promising alternative. A previous validity study demonstrated data derived from a single-channel, wireless system (NeuroSky ThinkGear, San Jose, California) is comparable to EEG recorded from conventional lab-based equipment. The current study evaluated the reliability of this portable system using test-retest and reliable change analyses. Relative power (RP) of delta, theta, alpha, and beta frequency bands was derived from EEG data obtained from a single electrode over FP1 in 19 healthy youth (10-17years old), 21 healthy adults (18-28years old), and 19 healthy older adults (55-79years old), during eyes-open, eyes-closed, auditory oddball, and visual n-back conditions. Intra-class correlations (ICCs) and Coefficients of Repeatability (CRs) were calculated from RP data re-collected one-day, one-week, and one-month later. Participants' levels of mood and attention were consistent across sessions. Eyes-closed resting EEG measurements using the portable device were reproducible (ICCs 0.76-0.85) at short and longer retest intervals in all three participant age groups. While still of at least fair reliability (ICCs 0.57-0.85), EEG obtained during eyes-open paradigms was less stable, and any change observed over time during these testing conditions can be interpreted utilizing the CR values provided. Combined with existing validity data, these findings encourage application of the portable EEG system for the study of brain function. PMID:27318008

  7. Decomposing EEG data into space-time-frequency components using Parallel Factor Analysis.

    PubMed

    Miwakeichi, Fumikazu; Martínez-Montes, Eduardo; Valdés-Sosa, Pedro A; Nishiyama, Nobuaki; Mizuhara, Hiroaki; Yamaguchi, Yoko

    2004-07-01

    Finding the means to efficiently summarize electroencephalographic data has been a long-standing problem in electrophysiology. A popular approach is identification of component modes on the basis of the time-varying spectrum of multichannel EEG recordings--in other words, a space/frequency/time atomic decomposition of the time-varying EEG spectrum. Previous work has been limited to only two of these dimensions. Principal Component Analysis (PCA) and Independent Component Analysis (ICA) have been used to create space/time decompositions; suffering an inherent lack of uniqueness that is overcome only by imposing constraints of orthogonality or independence of atoms. Conventional frequency/time decompositions ignore the spatial aspects of the EEG. Framing of the data being as a three-way array indexed by channel, frequency, and time allows the application of a unique decomposition that is known as Parallel Factor Analysis (PARAFAC). Each atom is the tri-linear decomposition into a spatial, spectral, and temporal signature. We applied this decomposition to the EEG recordings of five subjects during the resting state and during mental arithmetic. Common to all subjects were two atoms with spectral signatures whose peaks were in the theta and alpha range. These signatures were modulated by physiological state, increasing during the resting stage for alpha and during mental arithmetic for theta. Furthermore, we describe a new method (Source Spectra Imaging or SSI) to estimate the location of electric current sources from the EEG spectrum. The topography of the theta atom is frontal and the maximum of the corresponding SSI solution is in the anterior frontal cortex. The topography of the alpha atom is occipital with maximum of the SSI solution in the visual cortex. We show that the proposed decomposition can be used to search for activity with a given spectral and topographic profile in new recordings, and that the method may be useful for artifact recognition and removal

  8. Modulation of cortical activity as a result of voluntary postural sway direction: an EEG study

    PubMed Central

    Slobounov, Semyon; Hallett, Mark; Cao, Cheng; Newell, Karl

    2008-01-01

    There is increasing evidence demonstrating the role of the cerebral cortex in human postural control. Modulation of EEG both in voltage and frequency domains has been observed preceding and following self-paced postural movements and those induced by external perturbations. The current study set out to provide additional evidence regarding the role of cerebral cortex in human postural control by specifically examining modulation of EEG as a function of postural sway direction. Twelve neurologically normal subjects were instructed to produce self-paced voluntary postural sways in the anterior-posterior (AP) and medial-lateral (ML) directions. The center of pressure dynamics and EEG both in voltage and frequency domains were extracted by averaging and Morlet wavelet techniques, respectively. The amplitude of movement-related cortical potentials (MRCP) was significantly higher preceding ML sways. Also, time-frequency wavelet coefficients (TF) indicated differential modulation of EEG within alpha, beta and gamma bands as a function of voluntary postural sway direction. Thus, ML sway appear to be more difficult and energy demanding tasks than the AP sway as reflected in differential modulation of EEG. These results are discussed within the conceptual framework of differential patterns of brain activation as a result of postural task complexity. PMID:18639613

  9. A Feasibility Study on a Single-Unit Wireless EEG Sensor

    PubMed Central

    Luan, Bo; Jia, Wenyan; Thirumala, Parthasarathy D.; Balzer, Jeffrey; Gao, Di; Sun, Mingui

    2015-01-01

    The electroencephalography (EEG) is a widely used diagnostic tool for a number of clinical applications, such as diagnosis of epilepsy and study of sleep. Traditionally, to acquire a single channel of EEG signal, at least three electrodes must be installed on the skin separated at certain distances. They must also be connected to an amplifier by electrode leads. These basic requirements are acceptable in most clinical laboratories, but are unacceptable in certain point-of-care applications, such as during patient transportation. In order to remove these requirements, we are designing a single-unit EEG sensor in the size of a U.S. penny. It contains multiple closely spaced dry electrodes that can hook onto the skin, an electronic circuitry for signal amplification, digitization and wireless transmission, and a battery providing power. In this paper, we answer two key questions regarding the feasibility of the single-unit design: 1) can the closely-spaced electrodes obtain EEG signal reliably? and 2) will the electrodes orientated in certain ways improve signal quality? We conducted experiments utilizing closely spaced electrodes to record the alpha wave in the EEG. Our results have shown positive answers to the two feasibility questions. PMID:26213719

  10. EEG and ocular correlates of circadian melatonin phase and human performance decrements during sleep loss

    NASA Technical Reports Server (NTRS)

    Cajochen, C.; Khalsa, S. B.; Wyatt, J. K.; Czeisler, C. A.; Dijk, D. J.

    1999-01-01

    The aim of this study was to quantify the associations between slow eye movements (SEMs), eye blink rate, waking electroencephalogram (EEG) power density, neurobehavioral performance, and the circadian rhythm of plasma melatonin in a cohort of 10 healthy men during up to 32 h of sustained wakefulness. The time course of neurobehavioral performance was characterized by fairly stable levels throughout the first 16 h of wakefulness followed by deterioration during the phase of melatonin secretion. This deterioration was closely associated with an increase in SEMs. Frontal low-frequency EEG activity (1-7 Hz) exhibited a prominent increase with time awake and little circadian modulation. EEG alpha activity exhibited circadian modulation. The dynamics of SEMs and EEG activity were phase locked to changes in neurobehavioral performance and lagged the plasma melatonin rhythm. The data indicate that frontal areas of the brain are more susceptible to sleep loss than occipital areas. Frontal EEG activity and ocular parameters may be used to monitor and predict changes in neurobehavioral performance associated with sleep loss and circadian misalignment.

  11. Convergence of EEG and fMRI measures of reward anticipation.

    PubMed

    Gorka, Stephanie M; Phan, K Luan; Shankman, Stewart A

    2015-12-01

    Deficits in reward anticipation are putative mechanisms for multiple psychopathologies. Research indicates that these deficits are characterized by reduced left (relative to right) frontal electroencephalogram (EEG) activity and blood oxygenation level-dependent (BOLD) signal abnormalities in mesolimbic and prefrontal neural regions during reward anticipation. Although it is often assumed that these two measures capture similar mechanisms, no study to our knowledge has directly examined the convergence between frontal EEG alpha asymmetry and functional magnetic resonance imaging (fMRI) during reward anticipation in the same sample. Therefore, the aim of the current study was to investigate if and where in the brain frontal EEG alpha asymmetry and fMRI measures were correlated in a sample of 40 adults. All participants completed two analogous reward anticipation tasks--once during EEG data collection and the other during fMRI data collection. Results indicated that the two measures do converge and that during reward anticipation, increased relative left frontal activity is associated with increased left anterior cingulate cortex (ACC)/medial prefrontal cortex (mPFC) and left orbitofrontal cortex (OFC) activation. This suggests that the two measures may similarly capture PFC functioning, which is noteworthy given the role of these regions in reward processing and the pathophysiology of disorders such as depression and schizophrenia. PMID:26394333

  12. Measurement of neural signals from inexpensive, wireless and dry EEG systems.

    PubMed

    Grummett, T S; Leibbrandt, R E; Lewis, T W; DeLosAngeles, D; Powers, D M W; Willoughby, J O; Pope, K J; Fitzgibbon, S P

    2015-07-01

    Electroencephalography (EEG) is challenged by high cost, immobility of equipment and the use of inconvenient conductive gels. We compared EEG recordings obtained from three systems that are inexpensive, wireless, and/or dry (no gel), against recordings made with a traditional, research-grade EEG system, in order to investigate the ability of these 'non-traditional' systems to produce recordings of comparable quality to a research-grade system. The systems compared were: Emotiv EPOC (inexpensive and wireless), B-Alert (wireless), g.Sahara (dry) and g.HIamp (research-grade). We compared the ability of the systems to demonstrate five well-studied neural phenomena: (1) enhanced alpha activity with eyes closed versus open; (2) visual steady-state response (VSSR); (3) mismatch negativity; (4) P300; and (5) event-related desynchronization/synchronization. All systems measured significant alpha augmentation with eye closure, and were able to measure VSSRs (although these were smaller with g.Sahara). The B-Alert and g.Sahara were able to measure the three time-locked phenomena equivalently to the g.HIamp. The Emotiv EPOC did not have suitably located electrodes for two of the tasks and synchronization considerations meant that data from the time-locked tasks were not assessed. The results show that inexpensive, wireless, or dry systems may be suitable for experimental studies using EEG, depending on the research paradigm, and within the constraints imposed by their limited electrode placement and number. PMID:26020164

  13. EEG Changes Due to Experimentally Induced 3G Mobile Phone Radiation

    PubMed Central

    Roggeveen, Suzanne; van Os, Jim; Viechtbauer, Wolfgang; Lousberg, Richel

    2015-01-01

    The aim of this study was to investigate whether a 15-minute placement of a 3G dialing mobile phone causes direct changes in EEG activity compared to the placement of a sham phone. Furthermore, it was investigated whether placement of the mobile phone on the ear or the heart would result in different outcomes. Thirty-one healthy females participated. All subjects were measured twice: on one of the two days the mobile phone was attached to the ear, the other day to the chest. In this single-blind, cross-over design, assessments in the sham phone condition were conducted directly preceding and following the mobile phone exposure. During each assessment, EEG activity and radiofrequency radiation were recorded jointly. Delta, theta, alpha, slowbeta, fastbeta, and gamma activity was computed. The association between radiation exposure and the EEG was tested using multilevel random regression analyses with radiation as predictor of main interest. Significant radiation effects were found for the alpha, slowbeta, fastbeta, and gamma bands. When analyzed separately, ear location of the phone was associated with significant results, while chest placement was not. The results support the notion that EEG alterations are associated with mobile phone usage and that the effect is dependent on site of placement. Further studies are required to demonstrate the physiological relevance of these findings. PMID:26053854

  14. EEG correlates of spontaneous self-referential thoughts: a cross-cultural study.

    PubMed

    Knyazev, Gennady G; Savostyanov, Alexander N; Volf, Nina V; Liou, Michelle; Bocharov, Andrey V

    2012-11-01

    The default mode network (DMN) has been mostly investigated using positron emission tomography and functional magnetic resonance imaging (fMRI) and has received mixed support in electroencephalographic (EEG) studies. In this study, after sLORETA transformation of EEG data, we applied group spatial independent component analysis which is routinely used in fMRI research. In three large and diverse samples coming from two different cultures (Russian and Taiwanese), spontaneous EEG data and retrospective questionnaire measures of subject's state, thoughts, and feelings during the EEG registration were collected. Regression analyses showed that appearance of spontaneous self-referential thoughts was best predicted by enhanced alpha activity within the DMN. Diminished theta and delta activity in the superior frontal gyrus and enhanced beta activity in the postcentral gyrus added to the prediction. The enhanced alpha activity prevailed in the posterior DMN hub in Russian, but in the anterior DMN hub in Taiwanese participants. Possible cross-cultural differences in personality and attitudes underlying this difference are discussed. PMID:22985738

  15. Neural Correlates of Action Observation and Execution in 14-Month-Old Infants: An Event-Related EEG Desynchronization Study

    ERIC Educational Resources Information Center

    Marshall, Peter J.; Young, Thomas; Meltzoff, Andrew N.

    2011-01-01

    There is increasing interest in neurobiological methods for investigating the shared representation of action perception and production in early development. We explored the extent and regional specificity of EEG desynchronization in the infant alpha frequency range (6-9 Hz) during action observation and execution in 14-month-old infants.…

  16. Differences in Cognitive Processes between Gifted, Intelligent, Creative, and Average Individuals While Solving Complex Problems: An EEG Study.

    ERIC Educational Resources Information Center

    Jausovec, Norbert

    2000-01-01

    Studied differences in cognitive processes related to creativity and intelligence using EEG coherence and power measures in the lower and upper alpha bands. Results of 2 experiments involving 49 and 48 right-handed student teachers suggest that creativity and intelligence are different abilities that also differ in the neurological activity…

  17. Technical and clinical analysis of microEEG: a miniature wireless EEG device designed to record high-quality EEG in the emergency department

    PubMed Central

    2012-01-01

    Background We describe and characterize the performance of microEEG compared to that of a commercially available and widely used clinical EEG machine. microEEG is a portable, battery-operated, wireless EEG device, developed by Bio-Signal Group to overcome the obstacles to routine use of EEG in emergency departments (EDs). Methods The microEEG was used to obtain EEGs from healthy volunteers in the EEG laboratory and ED. The standard system was used to obtain EEGs from healthy volunteers in the EEG laboratory, and studies recorded from patients in the ED or ICU were also used for comparison. In one experiment, a signal splitter was used to record simultaneous microEEG and standard EEG from the same electrodes. Results EEG signal analysis techniques indicated good agreement between microEEG and the standard system in 66 EEGs recorded in the EEG laboratory and the ED. In the simultaneous recording the microEEG and standard system signals differed only in a smaller amount of 60 Hz noise in the microEEG signal. In a blinded review by a board-certified clinical neurophysiologist, differences in technical quality or interpretability were insignificant between standard recordings in the EEG laboratory and microEEG recordings from standard or electrode cap electrodes in the ED or EEG laboratory. The microEEG data recording characteristics such as analog-to-digital conversion resolution (16 bits), input impedance (>100MΩ), and common-mode rejection ratio (85 dB) are similar to those of commercially available systems, although the microEEG is many times smaller (88 g and 9.4 × 4.4 × 3.8 cm). Conclusions Our results suggest that the technical qualities of microEEG are non-inferior to a standard commercially available EEG recording device. EEG in the ED is an unmet medical need due to space and time constraints, high levels of ambient electrical noise, and the cost of 24/7 EEG technologist availability. This study suggests that using microEEG with an electrode cap

  18. Preterm EEG: a multimodal neurophysiological protocol.

    PubMed

    Stjerna, Susanna; Voipio, Juha; Metsäranta, Marjo; Kaila, Kai; Vanhatalo, Sampsa

    2012-01-01

    Since its introduction in early 1950s, electroencephalography (EEG) has been widely used in the neonatal intensive care units (NICU) for assessment and monitoring of brain function in preterm and term babies. Most common indications are the diagnosis of epileptic seizures, assessment of brain maturity, and recovery from hypoxic-ischemic events. EEG recording techniques and the understanding of neonatal EEG signals have dramatically improved, but these advances have been slow to penetrate through the clinical traditions. The aim of this presentation is to bring theory and practice of advanced EEG recording available for neonatal units. In the theoretical part, we will present animations to illustrate how a preterm brain gives rise to spontaneous and evoked EEG activities, both of which are unique to this developmental phase, as well as crucial for a proper brain maturation. Recent animal work has shown that the structural brain development is clearly reflected in early EEG activity. Most important structures in this regard are the growing long range connections and the transient cortical structure, subplate. Sensory stimuli in a preterm baby will generate responses that are seen at a single trial level, and they have underpinnings in the subplate-cortex interaction. This brings neonatal EEG readily into a multimodal study, where EEG is not only recording cortical function, but it also tests subplate function via different sensory modalities. Finally, introduction of clinically suitable dense array EEG caps, as well as amplifiers capable of recording low frequencies, have disclosed multitude of brain activities that have as yet been overlooked. In the practical part of this video, we show how a multimodal, dense array EEG study is performed in neonatal intensive care unit from a preterm baby in the incubator. The video demonstrates preparation of the baby and incubator, application of the EEG cap, and performance of the sensory stimulations. PMID:22371054

  19. Editorial: EEG Phenomenology and Multiple Faces of Short-term EEG Spectral Pattern

    PubMed Central

    Fingelkurts, Al. A; Fingelkurts, An. A

    2010-01-01

    An electroencephalogram (EEG) signal is extremely nonstationary, highly composite and very complex, all of which reflects the underlying integral neurodynamics. Understanding the EEG “grammar”, its internal structural organization would place a “Rozetta stone” in researchers’ hands, allowing them to more adequately describe the information processes of the brain in terms of EEG phenomenology. This Special Issue presents a framework where short-term EEG spectral pattern (SP) of a particular type is viewed as an information-rich event in EEG phenomenology. It is suggested that transition from one type of SP to another is accompanied by a “switch” between brain microstates in specific neuronal networks, or in cortex areas; and these microstates are reflected in EEG as piecewise stationary segments. In this context multiple faces of a short-term EEG SP reflect the poly-operational structure of brain activity. PMID:21347201

  20. Radiofrequency signal affects alpha band in resting electroencephalogram.

    PubMed

    Ghosn, Rania; Yahia-Cherif, Lydia; Hugueville, Laurent; Ducorps, Antoine; Lemaréchal, Jean-Didier; Thuróczy, György; de Seze, René; Selmaoui, Brahim

    2015-04-01

    The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8-12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant (P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session (P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG. PMID:25695646

  1. Radiofrequency signal affects alpha band in resting electroencephalogram

    PubMed Central

    Ghosn, Rania; Yahia-Cherif, Lydia; Hugueville, Laurent; Ducorps, Antoine; Lemaréchal, Jean-Didier; Thuróczy, György; de Seze, René

    2015-01-01

    The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8–12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant (P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session (P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG. PMID:25695646

  2. Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Gabard-Durnam, Laurel; Tierney, Adrienne L.; Vogel-Farley, Vanessa; Tager-Flusberg, Helen; Nelson, Charles A.

    2015-01-01

    An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of…

  3. EEG applications for sport and performance.

    PubMed

    Thompson, Trevor; Steffert, Tony; Ros, Tomas; Leach, Joseph; Gruzelier, John

    2008-08-01

    One approach to understanding processes that underlie skilled performing has been to study electrical brain activity using electroencephalography (EEG). A notorious problem with EEG is that genuine cerebral data is often contaminated by artifacts of non-cerebral origin. Unfortunately, such artifacts tend to be exacerbated when the subject is in motion, meaning that obtaining reliable data during exercise is inherently problematic. These problems may explain the limited number of studies using EEG as a methodological tool in the sports sciences. This paper discusses how empirical studies have generally tackled the problem of movement artifact by adopting alternative paradigms which avoid recording during actual physical exertion. Moreover, the specific challenges that motion presents to obtaining reliable EEG data are discussed along with practical and computational techniques to confront these challenges. Finally, as EEG recording in sports is often underpinned by a desire to optimise performance, a brief review of EEG-biofeedback and peak performance studies is also presented. A knowledge of practical aspects of EEG recording along with the advent of new technology and increasingly sophisticated processing models offer a promising approach to minimising, if perhaps not entirely circumventing, the problem of obtaining reliable EEG data during motion. PMID:18682293

  4. American Clinical Neurophysiology Society: EEG Guidelines Introduction.

    PubMed

    Tsuchida, Tammy N; Acharya, Jayant N; Halford, Jonathan J; Kuratani, John D; Sinha, Saurabh R; Stecker, Mark M; Tatum, William O; Drislane, Frank W

    2016-08-01

    This revision to the EEG Guidelines is an update incorporating current EEG technology and practice. "Standards of practice in clinical electroencephalography" (previously Guideline 4) has been removed. It is currently undergoing revision through collaboration among multiple medical societies and will become part of "Qualifications and Responsibilities of Personnel Performing and Interpreting Clinical Neurophysiology Procedures." The remaining guidelines are reordered and renumbered. PMID:27482792

  5. Analysis of EEG Related Saccadic Eye Movement

    NASA Astrophysics Data System (ADS)

    Funase, Arao; Kuno, Yoshiaki; Okuma, Shigeru; Yagi, Tohru

    Our final goal is to establish the model for saccadic eye movement that connects the saccade and the electroencephalogram(EEG). As the first step toward this goal, we recorded and analyzed the saccade-related EEG. In the study recorded in this paper, we tried detecting a certain EEG that is peculiar to the eye movement. In these experiments, each subject was instructed to point their eyes toward visual targets (LEDs) or the direction of the sound sources (buzzers). In the control cases, the EEG was recorded in the case of no eye movemens. As results, in the visual experiments, we found that the potential of EEG changed sharply on the occipital lobe just before eye movement. Furthermore, in the case of the auditory experiments, similar results were observed. In the case of the visual experiments and auditory experiments without eye movement, we could not observed the EEG changed sharply. Moreover, when the subject moved his/her eyes toward a right-side target, a change in EEG potential was found on the right occipital lobe. On the contrary, when the subject moved his/her eyes toward a left-side target, a sharp change in EEG potential was found on the left occipital lobe.

  6. EEG Spectral Features Discriminate between Alzheimer’s and Vascular Dementia

    PubMed Central

    Neto, Emanuel; Allen, Elena A.; Aurlien, Harald; Nordby, Helge; Eichele, Tom

    2015-01-01

    Alzheimer’s disease (AD) and vascular dementia (VaD) present with similar clinical symptoms of cognitive decline, but the underlying pathophysiological mechanisms differ. To determine whether clinical electroencephalography (EEG) can provide information relevant to discriminate between these diagnoses, we used quantitative EEG analysis to compare the spectra between non-medicated patients with AD (n = 77) and VaD (n = 77) and healthy elderly normal controls (NC) (n = 77). We use curve-fitting with a combination of a power loss and Gaussian function to model the averaged resting-state spectra of each EEG channel extracting six parameters. We assessed the performance of our model and tested the extracted parameters for group differentiation. We performed regression analysis in a multivariate analysis of covariance with group, age, gender, and number of epochs as predictors and further explored the topographical group differences with pair-wise contrasts. Significant topographical differences between the groups were found in several of the extracted features. Both AD and VaD groups showed increased delta power when compared to NC, whereas the AD patients showed a decrease in alpha power for occipital and temporal regions when compared with NC. The VaD patients had higher alpha power than NC and AD. The AD and VaD groups showed slowing of the alpha rhythm. Variability of the alpha frequency was wider for both AD and VaD groups. There was a general decrease in beta power for both AD and VaD. The proposed model is useful to parameterize spectra, which allowed extracting relevant clinical EEG key features that move toward simple and interpretable diagnostic criteria. PMID:25762978

  7. The default mode network and EEG α oscillations: an independent component analysis.

    PubMed

    Knyazev, Gennady G; Slobodskoj-Plusnin, Jaroslav Y; Bocharov, Andrey V; Pylkova, Liudmila V

    2011-07-21

    The default mode network (DMN) has been principally investigated using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) and has received mixed support in electroencephalographic (EEG) studies. In particular, the existing evidence is too inconsistent to allow formulation of specific hypotheses linking DMN activity to traditional EEG frequency bands. In this study, we aimed to test whether blind decomposition methods are able to identify in EEG data spatial patterns resembling the DMN as it is described in PET and fMRI studies. Further we aimed to test a degree of task-relatedness of DMN patterns identified in the traditional EEG frequency bands. To answer these questions we collected data both in a resting state and during performance of two experimental tasks: an explicit judgment of facial affect and a social game task. Individual differences in amount of self-referential thoughts during the resting state were measured by a short self-report scale. Only alpha band spatial patterns simultaneously showed a considerable overlap with the DMN and high correlations with presumptive DMN function-related outcomes both in the resting state and during the social game task. Spontaneous self-referential thoughts were associated with enhanced alpha activity in the posterior DMN hub, whereas processing of DMN function-related external stimuli disrupted this activity and simultaneously caused partial alpha phase-locking to external events. This evidence implies that synchronization of internal mental processes, as opposed to the processing of external stimuli, might be the primary function of alpha oscillations which is bound to be related to activity of the DMN. PMID:21683942

  8. Functional Connectivity Changes in Resting-State EEG as Potential Biomarker for Amyotrophic Lateral Sclerosis

    PubMed Central

    Iyer, Parameswaran Mahadeva; Egan, Catriona; Pinto-Grau, Marta; Burke, Tom; Elamin, Marwa; Nasseroleslami, Bahman; Pender, Niall; Lalor, Edmund C.; Hardiman, Orla

    2015-01-01

    Background Amyotrophic Lateral Sclerosis (ALS) is heterogeneous and overlaps with frontotemporal dementia. Spectral EEG can predict damage in structural and functional networks in frontotemporal dementia but has never been applied to ALS. Methods 18 incident ALS patients with normal cognition and 17 age matched controls underwent 128 channel EEG and neuropsychology assessment. The EEG data was analyzed using FieldTrip software in MATLAB to calculate simple connectivity measures and scalp network measures. sLORETA was used in nodal analysis for source localization and same methods were applied as above to calculate nodal network measures. Graph theory measures were used to assess network integrity. Results Cross spectral density in alpha band was higher in patients. In ALS patients, increased degree values of the network nodes was noted in the central and frontal regions in the theta band across seven of the different connectivity maps (p<0.0005). Among patients, clustering coefficient in alpha and gamma bands was increased in all regions of the scalp and connectivity were significantly increased (p=0.02). Nodal network showed increased assortativity in alpha band in the patients group. The Clustering Coefficient in Partial Directed Connectivity (PDC) showed significantly higher values for patients in alpha, beta, gamma, theta and delta frequencies (p=0.05). Discussion There is increased connectivity in the fronto-central regions of the scalp and areas corresponding to Salience and Default Mode network in ALS, suggesting a pathologic disruption of neuronal networking in early disease states. Spectral EEG has potential utility as a biomarker in ALS. PMID:26091258

  9. Simultaneous EEG-fMRI at ultra-high field: artifact prevention and safety assessment.

    PubMed

    Jorge, João; Grouiller, Frédéric; Ipek, Özlem; Stoermer, Robert; Michel, Christoph M; Figueiredo, Patrícia; van der Zwaag, Wietske; Gruetter, Rolf

    2015-01-15

    The simultaneous recording of scalp electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) can provide unique insights into the dynamics of human brain function, and the increased functional sensitivity offered by ultra-high field fMRI opens exciting perspectives for the future of this multimodal approach. However, simultaneous recordings are susceptible to various types of artifacts, many of which scale with magnetic field strength and can seriously compromise both EEG and fMRI data quality in recordings above 3T. The aim of the present study was to implement and characterize an optimized setup for simultaneous EEG-fMRI in humans at 7 T. The effects of EEG cable length and geometry for signal transmission between the cap and amplifiers were assessed in a phantom model, with specific attention to noise contributions from the MR scanner coldheads. Cable shortening (down to 12 cm from cap to amplifiers) and bundling effectively reduced environment noise by up to 84% in average power and 91% in inter-channel power variability. Subject safety was assessed and confirmed via numerical simulations of RF power distribution and temperature measurements on a phantom model, building on the limited existing literature at ultra-high field. MRI data degradation effects due to the EEG system were characterized via B0 and B1(+) field mapping on a human volunteer, demonstrating important, although not prohibitive, B1 disruption effects. With the optimized setup, simultaneous EEG-fMRI acquisitions were performed on 5 healthy volunteers undergoing two visual paradigms: an eyes-open/eyes-closed task, and a visual evoked potential (VEP) paradigm using reversing-checkerboard stimulation. EEG data exhibited clear occipital alpha modulation and average VEPs, respectively, with concomitant BOLD signal changes. On a single-trial level, alpha power variations could be observed with relative confidence on all trials; VEP detection was more limited, although

  10. EEG entropy measures in anesthesia

    PubMed Central

    Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli

    2015-01-01

    Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation

  11. Functional Connectivity and Quantitative EEG in Women with Alcohol Use Disorders: A Resting-State Study.

    PubMed

    Herrera-Díaz, Adianes; Mendoza-Quiñones, Raúl; Melie-Garcia, Lester; Martínez-Montes, Eduardo; Sanabria-Diaz, Gretel; Romero-Quintana, Yuniel; Salazar-Guerra, Iraklys; Carballoso-Acosta, Mario; Caballero-Moreno, Antonio

    2016-05-01

    This study was aimed at exploring the electroencephalographic features associated with alcohol use disorders (AUD) during a resting-state condition, by using quantitative EEG and Functional Connectivity analyses. In addition, we explored whether EEG functional connectivity is associated with trait impulsivity. Absolute and relative powers and Synchronization Likelihood (SL) as a measure of functional connectivity were analyzed in 15 AUD women and fifteen controls matched in age, gender and education. Correlation analysis between self-report impulsivity as measured by the Barratt impulsiveness Scale (BIS-11) and SL values of AUD patients were performed. Our results showed increased absolute and relative beta power in AUD patients compared to matched controls, and reduced functional connectivity in AUD patients predominantly in the beta and alpha bands. Impaired connectivity was distributed at fronto-central and occipito-parietal regions in the alpha band, and over the entire scalp in the beta band. We also found that impaired functional connectivity particularly in alpha band at fronto-central areas was negative correlated with non-planning dimension of impulsivity. These findings suggest that functional brain abnormalities are present in AUD patients and a disruption of resting-state EEG functional connectivity is associated with psychopathological traits of addictive behavior. PMID:26660886

  12. Serum anticholinergic activity and cerebral cholinergic dysfunction: An EEG study in frail elderly with and without delirium

    PubMed Central

    Thomas, Christine; Hestermann, Ute; Kopitz, Juergen; Plaschke, Konstanze; Oster, Peter; Driessen, Martin; Mundt, Christoph; Weisbrod, Matthias

    2008-01-01

    Background Delirium increases morbidity, mortality and healthcare costs especially in the elderly. Serum anticholinergic activity (SAA) is a suggested biomarker for anticholinergic burden and delirium risk, but the association with cerebral cholinergic function remains unclear. To clarify this relationship, we prospectively assessed the correlation of SAA with quantitative electroencephalography (qEEG) power, delirium occurrence, functional and cognitive measures in a cross-sectional sample of acutely hospitalized elderly (> 80 y) with high dementia and delirium prevalence. Methods 61 consecutively admitted patients over 80 years underwent an extensive clinical and neuropsychological evaluation. SAA was determined by using radio receptor assay as developed by Tune, and standard as well as quantitative EEGs were obtained. Results 15 patients had dementia with additional delirium (DD) according to expert consensus using DSM-IV criteria, 31 suffered from dementia without delirium (D), 15 were cognitively unimpaired (CU). SAA was clearly detectable in all patients but one (mean 10.9 ± 7.1 pmol/ml), but was not associated with expert-panel approved delirium diagnosis or cognitive functions. Delirium-associated EEG abnormalities included occipital slowing, peak power and alpha decrease, delta and theta power increase and slow wave ratio increase during active delirious states. EEG measures correlated significantly with cognitive performance and delirium severity, but not with SAA levels. Conclusion In elderly with acute disease, EEG parameters reliable indicate delirium, but SAA does not seem to reflect cerebral cholinergic function as measured by EEG and is not related to delirium diagnosis. PMID:18793418

  13. Tracking rhythm in long-term EEG recordings using empirical mode calculation.

    PubMed

    Lipping, Tarmo; Anier, Andres; Ratsep, Indrek; Kleemann, Piret; Toome, Valdo; Jantti, Ville

    2008-01-01

    A novel algorithm for the detection and tracking of rhythmic patterns in the EEG signal is presented. The algorithm includes the following steps: 1) linear filtering using symmetric impulse response, 2) calculation of the first intrinsic mode of the filter output and 3) calculation of instantaneous frequency and amplitude using the Hilbert transform. The linear filter is adapted according to the instantaneous frequency. The algorithm is shown to perform well in tracking the alpha rhythm (the alpha coma pattern) in critically ill patients sedated with midazolam. PMID:19163489

  14. Oscillatory EEG Correlates of Arithmetic Strategies: A Training Study

    PubMed Central

    Grabner, Roland H.; De Smedt, Bert

    2012-01-01

    There has been a long tradition of research on mathematics education showing that children and adults use different strategies to solve arithmetic problems. Neurophysiological studies have recently begun to investigate the brain correlates of these strategies. The existing body of data, however, reflect static end points of the learning process and do not provide information on how brain activity changes in response to training or intervention. In this study, we explicitly address this issue by training participants in using fact retrieval strategies. We also investigate whether brain activity related to arithmetic fact learning is domain-specific or whether this generalizes to other learning materials, such as the solution of figural-spatial problems. Twenty adult students were trained on sets of two-digit multiplication problems and figural-spatial problems. After the training, they were presented with the trained and untrained problems while their brain activity was recorded by means of electroencephalography (EEG). In both problem types, the training resulted in accuracies over 90% and significant decreases in solution times. Analyses of the oscillatory EEG data also revealed training effects across both problem types. Specifically, we observed training-related activity increases in the theta band (3–6 Hz) and decreases in the lower alpha band (8–10 Hz), especially over parietooccipital and parietal brain regions. These results provide the first evidence that a short-term fact retrieval training results in significant changes in oscillatory EEG activity. These findings further corroborate the role of the theta band in the retrieval of semantic information from memory and suggest that theta activity is sensitive to fact retrieval not only in mental arithmetic but also in other domains. PMID:23162495

  15. EEG correlates of spatial orientation in the human retrosplenial complex.

    PubMed

    Lin, C-T; Chiu, T-C; Gramann, K

    2015-10-15

    Studies on spatial navigation reliably demonstrate that the retrosplenial complex (RSC) plays a pivotal role for allocentric spatial information processing by transforming egocentric and allocentric spatial information into the respective other spatial reference frame (SRF). While more and more imaging studies investigate the role of the RSC in spatial tasks, high temporal resolution measures such as electroencephalography (EEG) are missing. To investigate the function of the RSC in spatial navigation with high temporal resolution we used EEG to analyze spectral perturbations during navigation based on allocentric and egocentric SRF. Participants performed a path integration task in a clearly structured virtual environment providing allothetic information. Continuous EEG recordings were decomposed by independent component analysis (ICA) with subsequent source reconstruction of independent time source series using equivalent dipole modeling. Time-frequency transformation was used to investigate reference frame-specific orientation processes during navigation as compared to a control condition with identical visual input but no orientation task. Our results demonstrate that navigation based on an egocentric reference frame recruited a network including the parietal, motor, and occipital cortices with dominant perturbations in the alpha band and theta modulation in frontal cortex. Allocentric navigation was accompanied by performance-related desynchronization of the 8-13 Hz frequency band and synchronization in the 12-14 Hz band in the RSC. The results support the claim that the retrosplenial complex is central to translating egocentric spatial information into allocentric reference frames. Modulations in different frequencies with different time courses in the RSC further provide first evidence of two distinct neural processes reflecting translation of spatial information based on distinct reference frames and the computation of heading changes. PMID:26163801

  16. Neural network model of cortical EEG response to olfactory stimuli

    NASA Astrophysics Data System (ADS)

    Dunbar, George L.; Van Toller, Steve

    1995-04-01

    We describe three experiments attempting to model differences in cortical EEG following stimulation with different odors. The data used in these experiments was obtained in previous studies, described briefly here. Subjects sit in an environmentally stabilized low odor cubicle. Twenty-eight electrodes are placed on the scalp and connect the subject to a neurosciences brain imager, which digitizes cortical EEG response. In a given trial, a specific odor is introduced, and the response recorded. In the first experiment, alpha wave data from a subset of ten electrodes and a single subject was used. In the original experiment, the subject was presented with a number of odors and the resulting brain electrical activity was resolved into 16 time slices (5 preceding presentation, 4 during presentation and 7 following presentation). Only data from frames 6, 7 and 8 (during presentation) was used here. A model was constructed to discriminate morning from afternoon responses. The network used measurements from 10 electrodes as input, and backpropagation was used for training. During training, the network was presented with responses to just one odor. Generalization was demonstrated for five other odors. The weights in the network have been analyzed and indicate a role for a specific group of electrode sites in this discrimination. The second experiment involved constructing a network to discriminate cortical EEG responses to two odors. In the original experiment from which we drew our data, fourteen subjects were presented with each odor once. Data from only the frame at first presentation of the odor were used here. Data from three subjects (chosen pseudo-randomly) was selected for use in the generalization phase and dropped from the training set. Output targets were constructed that took account of subjective ratings of `pleasantness.' A feed-forward network with twenty-eight input units was trained using data from the eleven remaining subjects, using conjugate gradient

  17. Circadian variation of EEG power spectra in NREM and REM sleep in humans: dissociation from body temperature

    NASA Technical Reports Server (NTRS)

    Dijk, D. J.

    1999-01-01

    In humans, EEG power spectra in REM and NREM sleep, as well as characteristics of sleep spindles such as their duration, amplitude, frequency and incidence, vary with circadian phase. Recently it has been hypothesized that circadian variations in EEG spectra in humans are caused by variations in brain or body temperature and may not represent phenomena relevant to sleep regulatory processes. To test this directly, a further analysis of EEG power spectra - collected in a forced desynchrony protocol in which sleep episodes were scheduled to a 28-h period while the rhythms of body temperature and plasma melatonin were oscillating at their near 24-h period - was carried out. EEG power spectra were computed for NREM and REM sleep occurring between 90-120 and 270-300 degrees of the circadian melatonin rhythm, i.e. just after the clearance of melatonin from plasma in the 'morning' and just after the 'evening' increase in melatonin secretion. Average body temperatures during scheduled sleep at these two circadian phases were identical (36.72 degrees C). Despite identical body temperatures, the power spectra in NREM sleep were very different at these two circadian phases. EEG activity in the low frequency spindle range was significantly and markedly enhanced after the evening increase in plasma melatonin as compared to the morning phase. For REM sleep, significant differences in power spectra during these two circadian phases, in particular in the alpha range, were also observed. The results confirm that EEG power spectra in NREM and REM sleep vary with circadian phase, suggesting that the direct contribution of temperature to the circadian variation in EEG power spectra is absent or only minor, and are at variance with the hypothesis that circadian variations in EEG power spectra are caused by variations in temperature.

  18. Optimal set of EEG features for emotional state classification and trajectory visualization in Parkinson's disease.

    PubMed

    Yuvaraj, R; Murugappan, M; Ibrahim, Norlinah Mohamed; Sundaraj, Kenneth; Omar, Mohd Iqbal; Mohamad, Khairiyah; Palaniappan, R

    2014-12-01

    In addition to classic motor signs and symptoms, individuals with Parkinson's disease (PD) are characterized by emotional deficits. Ongoing brain activity can be recorded by electroencephalograph (EEG) to discover the links between emotional states and brain activity. This study utilized machine-learning algorithms to categorize emotional states in PD patients compared with healthy controls (HC) using EEG. Twenty non-demented PD patients and 20 healthy age-, gender-, and education level-matched controls viewed happiness, sadness, fear, anger, surprise, and disgust emotional stimuli while fourteen-channel EEG was being recorded. Multimodal stimulus (combination of audio and visual) was used to evoke the emotions. To classify the EEG-based emotional states and visualize the changes of emotional states over time, this paper compares four kinds of EEG features for emotional state classification and proposes an approach to track the trajectory of emotion changes with manifold learning. From the experimental results using our EEG data set, we found that (a) bispectrum feature is superior to other three kinds of features, namely power spectrum, wavelet packet and nonlinear dynamical analysis; (b) higher frequency bands (alpha, beta and gamma) play a more important role in emotion activities than lower frequency bands (delta and theta) in both groups and; (c) the trajectory of emotion changes can be visualized by reducing subject-independent features with manifold learning. This provides a promising way of implementing visualization of patient's emotional state in real time and leads to a practical system for noninvasive assessment of the emotional impairments associated with neurological disorders. PMID:25109433

  19. Separation of circadian and wake duration-dependent modulation of EEG activation during wakefulness

    NASA Technical Reports Server (NTRS)

    Cajochen, C.; Wyatt, J. K.; Czeisler, C. A.; Dijk, D. J.

    2002-01-01

    The separate contribution of circadian rhythmicity and elapsed time awake on electroencephalographic (EEG) activity during wakefulness was assessed. Seven men lived in an environmental scheduling facility for 4 weeks and completed fourteen 42.85-h 'days', each consisting of an extended (28.57-h) wake episode and a 14.28-h sleep opportunity. The circadian rhythm of plasma melatonin desynchronized from the 42.85-h day. This allowed quantification of the separate contribution of circadian phase and elapsed time awake to variation in EEG power spectra (1-32 Hz). EEG activity during standardized behavioral conditions was markedly affected by both circadian phase and elapsed time awake in an EEG frequency- and derivation-specific manner. The nadir of the circadian rhythm in alpha (8-12 Hz) activity in both fronto-central and occipito-parietal derivations occurred during the biological night, close to the crest of the melatonin rhythm. The nadir of the circadian rhythm of theta (4.5-8 Hz) and beta (20-32 Hz) activity in the fronto-central derivation was located close to the onset of melatonin secretion, i.e. during the wake maintenance zone. As time awake progressed, delta frequency (1-4.5 Hz) and beta (20-32 Hz) activity rose monotonically in frontal derivations. The interaction between the circadian and wake-dependent increase in frontal delta was such that the intrusion of delta was minimal when sustained wakefulness coincided with the biological day, but pronounced during the biological night. Our data imply that the circadian pacemaker facilitates frontal EEG activation during the wake maintenance zone, by generating an arousal signal that prevents the intrusion of low-frequency EEG components, the propensity for which increases progressively during wakefulness.

  20. Scalp EEG does not predict hemispherectomy outcome

    PubMed Central

    Greiner, Hansel M.; Park, Yong D.; Holland, Katherine; Horn, Paul S.; Byars, Anna W.; Mangano, Francesco T.; Smith, Joseph R.; Lee, Mark R.; Lee, Ki-Hyeong

    2012-01-01

    Background Functional hemispherectomy is effective in carefully selected patients, resulting in a reduction of seizure burden up to complete resolution, improvement of intellectual development, and developmental benefit despite possible additional neurological deficit. Despite apparent hemispheric pathology on brain magnetic resonance imaging (MRI) or other imaging tests, scalp electroencephalography (EEG) could be suggestive of bilateral ictal onset or even ictal onset contralateral to the dominant imaging abnormality. We aimed to investigate the role of scalp EEG lateralization pre-operatively in predicting outcome. Methods We retrospectively reviewed 54 patients who underwent hemispherectomy between 1991 and 2009 at Medical College of Georgia (1991–2006) and Cincinnati Children’s Hospital Medical Center (2006–2009) and had at least one year post-operative follow-up. All preoperative EEGs were reviewed, and classified as either lateralizing or nonlateralizing, for both ictal and interictal EEG recordings. Results Of 54 patients, 42 (78%) became seizure free. Twenty-four (44%) of 54 had a nonlateralizing ictal or interictal EEG. Further analysis was based on etiology of epilepsy, including malformation of cortical development (MCD), Rasmussen syndrome (RS), and stroke (CVA). EEG nonlateralization did not predict poor outcome in any of the etiology groups evaluated. Conclusion Scalp EEG abnormalities in contralateral or bilateral hemispheres do not, in isolation, predict a poor outcome from hemispherectomy. Results of other non-invasive and invasive evaluations should be used to determine candidacy. PMID:21813300

  1. Making the case for mobile cognition: EEG and sports performance.

    PubMed

    Park, Joanne L; Fairweather, Malcolm M; Donaldson, David I

    2015-05-01

    In the high stakes world of International sport even the smallest change in performance can make the difference between success and failure, leading sports professionals to become increasingly interested in the potential benefits of neuroimaging. Here we describe evidence from EEG studies that either identify neural signals associated with expertise in sport, or employ neurofeedback to improve performance. Evidence for the validity of neurofeedback as a technique for enhancing sports performance remains limited. By contrast, progress in characterizing the neural correlates of sporting behavior is clear: frequency domain studies link expert performance to changes in alpha rhythms, whilst time-domain studies link expertise in response evaluation and motor output with modulations of P300 effects and readiness potentials. Despite early promise, however, findings have had relatively little impact for sports professionals, at least in part because there has been a mismatch between lab tasks and real sporting activity. After selectively reviewing existing findings and outlining limitations, we highlight developments in mobile EEG technology that offer new opportunities for sports neuroscience. PMID:25735956

  2. Brain Networks Responsible for Sense of Agency: An EEG Study

    PubMed Central

    Shim, Miseon; Nahab, Fatta B.; Park, Jihye; Kim, Do-Won; Kakareka, John; Miletta, Nathanial; Hallett, Mark

    2015-01-01

    Background Self-agency (SA) is a person’s feeling that his action was generated by himself. The neural substrates of SA have been investigated in many neuroimaging studies, but the functional connectivity of identified regions has rarely been investigated. The goal of this study is to investigate the neural network related to SA. Methods SA of hand movements was modulated with virtual reality. We examined the cortical network relating to SA modulation with electroencephalography (EEG) power spectrum and phase coherence of alpha, beta, and gamma frequency bands in 16 right-handed, healthy volunteers. Results In the alpha band, significant relative power changes and phase coherence of alpha band were associated with SA modulation. The relative power decrease over the central, bilateral parietal, and right temporal regions (C4, Pz, P3, P4, T6) became larger as participants more effectively controlled the virtual hand movements. The phase coherence of the alpha band within frontal areas (F7-FP2, F7-Fz) was directly related to changes in SA. The functional connectivity was lower as the participants felt that they could control their virtual hand. In the other frequency bands, significant phase coherences were observed in the frontal (or central) to parietal, temporal, and occipital regions during SA modulation (Fz-O1, F3-O1, Cz-O1, C3-T4L in beta band; FP1-T6, FP1-O2, F7-T4L, F8-Cz in gamma band). Conclusions Our study suggests that alpha band activity may be the main neural oscillation of SA, which suggests that the neural network within the anterior frontal area may be important in the generation of SA. PMID:26270552

  3. [Continuous EEG monitoring for aneurysmal subarachnoid hemorrhage].

    PubMed

    Pugin, D; Vulliemoz, S; Bijlenga, P; Gasche, Y

    2014-12-10

    Subarachnoid hemorrhage (SAH) still carries a high morbidity and mortality, despite improvement in surgical and medical management. Seizures and delayed cerebral ischemia (DCI) secondary to vasospasm or cortical spreading depression are frequent after SAH. Continuous EEG allows early detection of non-convulsive seizures or delayed cerebral ischemia and may become a promissing tool in the monitoring of SAH patients. However, its use in clinical practice is still limited because many resources are required for recording and analyzing continuous EEG. Moreover, we require more data to confirm the relationship between aggressive treatment of non-convulsive seizure or delayed cerebral ischemia triggered by continuous EEG and outcome. PMID:25632630

  4. Enabling computer decisions based on EEG input

    NASA Technical Reports Server (NTRS)

    Culpepper, Benjamin J.; Keller, Robert M.

    2003-01-01

    Multilayer neural networks were successfully trained to classify segments of 12-channel electroencephalogram (EEG) data into one of five classes corresponding to five cognitive tasks performed by a subject. Independent component analysis (ICA) was used to segregate obvious artifact EEG components from other sources, and a frequency-band representation was used to represent the sources computed by ICA. Examples of results include an 85% accuracy rate on differentiation between two tasks, using a segment of EEG only 0.05 s long and a 95% accuracy rate using a 0.5-s-long segment.

  5. EEG neurofeedback effects in the treatment of adolescent anorexia nervosa.

    PubMed

    Lackner, Nina; Unterrainer, Human-Friedrich; Skliris, Dimitris; Shaheen, Sandra; Dunitz-Scheer, Marguerite; Wood, Guilherme; Scheer, Peter Jaron Zwi; Wallner-Liebmann, Sandra Johanna; Neuper, Christa

    2016-01-01

    A pre-post design including 22 females was used to evaluate the effectiveness of neurofeedback in the treatment of adolescent anorexia nervosa. Resting EEG measures and a psychological test-battery assessing eating behavior traits, clinical symptoms, emotionality, and mood were obtained. While both the experimental (n = 10) and control group (n = 12) received their usual maintenance treatment, the experimental group received 10 sessions of individual alpha frequency training over a period of 5 weeks as additional treatment. Significant training effects were shown in eating behavior traits, emotion regulation, and in relative theta power in the eyes closed condition. Although the results are limited due to the small sample size, these are the first empirical data demonstrating the benefits of neurofeedback as a treatment adjunct in individuals with anorexia nervosa. PMID:27027700

  6. Multidimensional Directed Phase Analysis for Basic Rhythm of EEG

    NASA Astrophysics Data System (ADS)

    Sakata, Osamu; Shiina, Tsuyoshi; Saito, Yoichi

    In this paper, multidimensional directed phase analysis is proposed as a means of causality analysis for multiple time series, is proposed. The multidimensional directed phase is a phase with causality, which is associated with multidimensional directed coherence. Using multidimensional directed phase analysis, direction and time of a signal flow among multidimensional time series can be estimated. In two simulations, artificial time series have been analyzed by the new method to confirm its characteristics. In first simulation, accuracy of estimation of signal flow time has been investigated. Second, a complex signal flow pattern has been analyzed. Next, the multidimensional directed phase analysis and the multidimensional directed coherence analysis have been applied to EEG data of normal volunteer. As a result, we have got information differ from common learning which is the difference between the phase of a frontal alpha waves and an occipital is π.

  7. The Diagnostic Accuracy of Prolonged Ambulatory Versus Routine EEG.

    PubMed

    Keezer, Mark R; Simard-Tremblay, Elisabeth; Veilleux, Martin

    2016-04-01

    Prolonged ambulatory electroencephalography (paEEG) is increasingly used in clinical practice but its diagnostic accuracy relative to that of routine EEG (rEEG) remains uncertain. We examined a consecutive sample of 72 individuals who had undergone 32-channel paEEG immediately after an rEEG, creating perfectly matched EEG samples. Each recording was prospectively assessed for epileptiform discharges (ED) and nonepileptiform abnormalities. The median paEEG duration was 22.5 hours (interquartile range: 22.0-23.0). The sensitivity of paEEG was 2.23 times greater than that of rEEG [sensitivity ratio: 2.23 (95% CI=1.49-3.34)] if a positive test was limited to the presence of epileptiform discharges. This benefit of paEEG versus rEEG was no longer evident if the definition of a positive test included nonepileptiform abnormalities (sensitivity ratio 1.26; 95% CI=1.02-1.55). The specificity of the 2 tests was not evidently different (specificity ratio 0.67; 95% CI=0.17-2.67). Twenty-six percent of paEEG recorded epileptic seizures while none of the rEEG did (absolute difference 26.0% (95% CI=11.8-40.2). Our findings quantify the benefit of 32-channel paEEG, relative to rEEG, and support its role in the diagnosis and characterization of epilepsy. PMID:26376916

  8. Chronic activation of peroxisome proliferator-activated receptor-alpha with fenofibrate prevents alterations in cardiac metabolic phenotype without changing the onset of decompensation in pacing-induced heart failure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Severe heart failure (HF) is characterized by profound alterations in cardiac metabolic phenotype, with down-regulation of the free fatty acid (FFA) oxidative pathway and marked increase in glucose oxidation. We tested whether fenofibrate, a pharmacological agonist of peroxisome proliferator-activat...

  9. Alpha Rhythms in Audition: Cognitive and Clinical Perspectives

    PubMed Central

    Weisz, Nathan; Hartmann, Thomas; Müller, Nadia; Lorenz, Isabel; Obleser, Jonas

    2011-01-01

    Like the visual and the sensorimotor systems, the auditory system exhibits pronounced alpha-like resting oscillatory activity. Due to the relatively small spatial extent of auditory cortical areas, this rhythmic activity is less obvious and frequently masked by non-auditory alpha-generators when recording non-invasively using magnetoencephalography (MEG) or electroencephalography (EEG). Following stimulation with sounds, marked desynchronizations can be observed between 6 and 12 Hz, which can be localized to the auditory cortex. However knowledge about the functional relevance of the auditory alpha rhythm has remained scarce so far. Results from the visual and sensorimotor system have fuelled the hypothesis of alpha activity reflecting a state of functional inhibition. The current article pursues several intentions: (1) Firstly we review and present own evidence (MEG, EEG, sEEG) for the existence of an auditory alpha-like rhythm independent of visual or motor generators, something that is occasionally met with skepticism. (2) In a second part we will discuss tinnitus and how this audiological symptom may relate to reduced background alpha. The clinical part will give an introduction into a method which aims to modulate neurophysiological activity hypothesized to underlie this distressing disorder. Using neurofeedback, one is able to directly target relevant oscillatory activity. Preliminary data point to a high potential of this approach for treating tinnitus. (3) Finally, in a cognitive neuroscientific part we will show that auditory alpha is modulated by anticipation/expectations with and without auditory stimulation. We will also introduce ideas and initial evidence that alpha oscillations are involved in the most complex capability of the auditory system, namely speech perception. The evidence presented in this article corroborates findings from other modalities, indicating that alpha-like activity functionally has an universal inhibitory role across sensory

  10. Using EEG to explore how rTMS produces its effects on behavior

    PubMed Central

    Johnson, Jeffrey S.; Hamidi, Massihullah; Postle, Bradley R.

    2010-01-01

    A commonly held view is that repetitive TMS (rTMS) influences behavior by producing transient “virtual lesions” in targeted tissue. However, findings of rTMS-related improvements in performance are difficult to reconcile with this assumption. With regard to the the mechanism of rTMS, a combined rTMS/EEG study conducted in our lab has revealed a complex set of relations between rTMS, EEG activity, and behavioral performance, with the effects of rTMS on power in the alpha band and on alpha:gamma phase synchrony each predicting its effect on behavior. These findings suggest that rTMS influences performance by biasing endogenous task-related oscillatory dynamics, rather than creating a “virtual lesion”. To further differentiate these two alternatives, in the present study we compared the effects of 10 Hz rTMS on neural activity with the results of an experiment in which rTMS was replaced with 10 Hz luminance flicker. We reasoned that 10 Hz flicker would produce widespread entrainment of neural activity to the flicker frequency, and comparison of these EEG results with those from the rTMS study would shed light on whether the latter also reflected entrainment to an exogenous stimulus. Results revealed pronounced evidence for “entrainment noise” produced by 10 Hz flicker – increased oscillatory power and inter-trial coherence (ITC) at the driving frequency, and increased alpha:gamma phase synchronization -- that were nonetheless largely uncorrelated with behavior. This contrasts markedly with 10-Hz rTMS, for which the only evidence for stimulation-induced noise, elevated ITC at 30 Hz, differed qualitatively from the flicker results. Simultaneous recording of the EEG thus offers an important means of directly testing assumptions about how rTMS exerts its effects on behavior. PMID:19915972

  11. Statistics over features: EEG signals analysis.

    PubMed

    Derya Ubeyli, Elif

    2009-08-01

    This paper presented the usage of statistics over the set of the features representing the electroencephalogram (EEG) signals. Since classification is more accurate when the pattern is simplified through representation by important features, feature extraction and selection play an important role in classifying systems such as neural networks. Multilayer perceptron neural network (MLPNN) architectures were formulated and used as basis for detection of electroencephalographic changes. Three types of EEG signals (EEG signals recorded from healthy volunteers with eyes open, epilepsy patients in the epileptogenic zone during a seizure-free interval, and epilepsy patients during epileptic seizures) were classified. The selected Lyapunov exponents, wavelet coefficients and the power levels of power spectral density (PSD) values obtained by eigenvector methods of the EEG signals were used as inputs of the MLPNN trained with Levenberg-Marquardt algorithm. The classification results confirmed that the proposed MLPNN has potential in detecting the electroencephalographic changes. PMID:19555931

  12. Correlation between amygdala BOLD activity and frontal EEG asymmetry during real-time fMRI neurofeedback training in patients with depression.

    PubMed

    Zotev, Vadim; Yuan, Han; Misaki, Masaya; Phillips, Raquel; Young, Kymberly D; Feldner, Matthew T; Bodurka, Jerzy

    2016-01-01

    Real-time fMRI neurofeedback (rtfMRI-nf) is an emerging approach for studies and novel treatments of major depressive disorder (MDD). EEG performed simultaneously with an rtfMRI-nf procedure allows an independent evaluation of rtfMRI-nf brain modulation effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been directly related to simultaneously acquired fMRI data. We report the first study investigating electrophysiological correlates of the rtfMRI-nf procedure, by combining the rtfMRI-nf with simultaneous and passive EEG recordings. In this pilot study, MDD patients in the experimental group (n = 13) learned to upregulate BOLD activity of the left amygdala using an rtfMRI-nf during a happy emotion induction task. MDD patients in the control group (n = 11) were provided with a sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper alpha band and BOLD activity across the brain were examined. Average individual changes in frontal EEG asymmetry during the rtfMRI-nf task for the experimental group showed a significant positive correlation with the MDD patients' depression severity ratings, consistent with an inverse correlation between the depression severity and frontal EEG asymmetry at rest. The average asymmetry changes also significantly correlated with the amygdala BOLD laterality. Temporal correlations between frontal EEG asymmetry and BOLD activity were significantly enhanced, during the rtfMRI-nf task, for the amygdala and many regions associated with emotion regulation. Our findings demonstrate an important link between amygdala BOLD activity and frontal EEG asymmetry during emotion regulation. Our EEG asymmetry results indicate that the rtfMRI-nf training targeting the amygdala is beneficial to MDD patients. They further suggest that EEG-nf based on frontal EEG asymmetry in the alpha band would be compatible with the amygdala

  13. Correlation between amygdala BOLD activity and frontal EEG asymmetry during real-time fMRI neurofeedback training in patients with depression

    PubMed Central

    Zotev, Vadim; Yuan, Han; Misaki, Masaya; Phillips, Raquel; Young, Kymberly D.; Feldner, Matthew T.; Bodurka, Jerzy

    2016-01-01

    Real-time fMRI neurofeedback (rtfMRI-nf) is an emerging approach for studies and novel treatments of major depressive disorder (MDD). EEG performed simultaneously with an rtfMRI-nf procedure allows an independent evaluation of rtfMRI-nf brain modulation effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been directly related to simultaneously acquired fMRI data. We report the first study investigating electrophysiological correlates of the rtfMRI-nf procedure, by combining the rtfMRI-nf with simultaneous and passive EEG recordings. In this pilot study, MDD patients in the experimental group (n = 13) learned to upregulate BOLD activity of the left amygdala using an rtfMRI-nf during a happy emotion induction task. MDD patients in the control group (n = 11) were provided with a sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper alpha band and BOLD activity across the brain were examined. Average individual changes in frontal EEG asymmetry during the rtfMRI-nf task for the experimental group showed a significant positive correlation with the MDD patients' depression severity ratings, consistent with an inverse correlation between the depression severity and frontal EEG asymmetry at rest. The average asymmetry changes also significantly correlated with the amygdala BOLD laterality. Temporal correlations between frontal EEG asymmetry and BOLD activity were significantly enhanced, during the rtfMRI-nf task, for the amygdala and many regions associated with emotion regulation. Our findings demonstrate an important link between amygdala BOLD activity and frontal EEG asymmetry during emotion regulation. Our EEG asymmetry results indicate that the rtfMRI-nf training targeting the amygdala is beneficial to MDD patients. They further suggest that EEG-nf based on frontal EEG asymmetry in the alpha band would be compatible with the amygdala

  14. Principal Dynamic Mode Analysis of EEG Data for Assisting the Diagnosis of Alzheimer’s Disease

    PubMed Central

    Escudero, Javier; Shin, Dae; Ifeachor, Emmanuel; Marmarelis, Vasilis

    2015-01-01

    We examine whether modeling of the causal dynamic relationships between frontal and occipital electroencephalogram (EEG) time-series recordings reveal reliable differentiating characteristics of Alzheimer’s patients versus control subjects in a manner that may assist clinical diagnosis of Alzheimer’s disease (AD). The proposed modeling approach utilizes the concept of principal dynamic modes (PDMs) and their associated nonlinear functions (ANF) and hypothesizes that the ANFs of some PDMs for the AD patients will be distinct from their counterparts in control subjects. To this purpose, global PDMs are extracted from 1-min EEG signals of 17 AD patients and 24 control subjects at rest using Volterra models estimated via Laguerre expansions, whereby the O1 or O2 recording is viewed as the input signal and the F3 or F4 recording as the output signal. Subsequent singular value decomposition of the estimated Volterra kernels yields the global PDMs that represent an efficient basis of functions for the representation of the EEG dynamics in all subjects. The respective ANFs are computed for each subject and characterize the specific dynamics of each subject. For comparison, signal features traditionally used in the analysis of EEG signals in AD are computed as benchmark. The results indicate that the ANFs of two specific PDMs, corresponding to the delta–theta and alpha bands, can delineate the two groups well. PMID:27170890

  15. Alpha Thalassemia

    MedlinePlus

    ... an apparently normal individual has a child with hemoglobin H disease or alpha thalassemia minor. It can ... gene on one chromosome 25% 25% 25% 25% hemoglobin H disease there is a 25% chance with ...

  16. Connectivity Measures in EEG Microstructural Sleep Elements

    PubMed Central

    Sakellariou, Dimitris; Koupparis, Andreas M.; Kokkinos, Vasileios; Koutroumanidis, Michalis; Kostopoulos, George K.

    2016-01-01

    During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting procedures. The connectivity patterns of the latter, among other aspects of sleep microstructure, are still to be fully elucidated. We suggest here a methodology for the assessment and investigation of the connectivity patterns of EEG microstructural elements, such as sleep spindles. The methodology combines techniques in the preprocessing, estimation, error assessing and visualization of results levels in order to allow the detailed examination of the connectivity aspects (levels and directionality of information flow) over frequency and time with notable resolution, while dealing with the volume conduction and EEG reference assessment. The high temporal and frequency resolution of the methodology will allow the association between the microelements and the dynamically forming networks that characterize them, and consequently possibly reveal aspects of the EEG microstructure. The proposed methodology is initially tested on artificially generated signals for proof of concept and subsequently applied to real EEG recordings via a custom built MATLAB-based tool developed for such studies. Preliminary results from 843 fast sleep spindles recorded in whole night sleep of 5 healthy volunteers indicate a prevailing pattern of interactions between centroparietal and frontal regions. We demonstrate hereby, an opening to our knowledge attempt to estimate the scalp EEG connectivity that characterizes fast sleep spindles via an “EEG-element connectivity” methodology we propose. The application of the latter, via a computational tool we developed suggests it is able to investigate the connectivity patterns related to the

  17. Alpha-theta effects associated with ageing during the Stroop test.

    PubMed

    Nombela, Cristina; Nombela, Manuel; Castell, Pedro; García, Teodoro; López-Coronado, Juan; Herrero, María Trinidad

    2014-01-01

    The Stroop effect is considered as a standard attentional measure to study conflict resolution in humans. The response of the brain to conflict is supposed to change over time and it is impaired in certain pathological conditions. Neuropsychological Stroop test measures have been complemented with electroencephalography (EEG) techniques to evaluate the mechanisms in the brain that underlie conflict resolution from the age of 20 to 70. To study the changes in EEG activity during life, we recruited a large sample of healthy subjects of different ages that included 90 healthy individuals, divided by age into decade intervals, which performed the Stroop test while recording a 14 channel EEG. The results highlighted an interaction between age and stimulus that was focused on the prefrontal (Alpha and Theta band) and Occipital (Alpha band) areas. We concluded that behavioural Stroop interference is directly influenced by opposing Alpha and Theta activity and evolves across the decades of life. PMID:24867024

  18. Alpha-Theta Effects Associated with Ageing during the Stroop Test

    PubMed Central

    Nombela, Cristina; Nombela, Manuel; Castell, Pedro; García, Teodoro; López-Coronado, Juan; Herrero, María Trinidad

    2014-01-01

    The Stroop effect is considered as a standard attentional measure to study conflict resolution in humans. The response of the brain to conflict is supposed to change over time and it is impaired in certain pathological conditions. Neuropsychological Stroop test measures have been complemented with electroencephalography (EEG) techniques to evaluate the mechanisms in the brain that underlie conflict resolution from the age of 20 to 70. To study the changes in EEG activity during life, we recruited a large sample of healthy subjects of different ages that included 90 healthy individuals, divided by age into decade intervals, which performed the Stroop test while recording a 14 channel EEG. The results highlighted an interaction between age and stimulus that was focused on the prefrontal (Alpha and Theta band) and Occipital (Alpha band) areas. We concluded that behavioural Stroop interference is directly influenced by opposing Alpha and Theta activity and evolves across the decades of life. PMID:24867024

  19. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration

    PubMed Central

    Bodala, Indu P.; Li, Junhua; Thakor, Nitish V.; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using “challenge integration,” a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean

  20. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration.

    PubMed

    Bodala, Indu P; Li, Junhua; Thakor, Nitish V; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using "challenge integration," a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean reaction

  1. Short-Term EEG Spectral Pattern as a Single Event in EEG Phenomenology

    PubMed Central

    Fingelkurts, Al. A; Fingelkurts, An. A

    2010-01-01

    Spectral decomposition, to this day, still remains the main analytical paradigm for the analysis of EEG oscillations. However, conventional spectral analysis assesses the mean characteristics of the EEG power spectra averaged out over extended periods of time and/or broad frequency bands, thus resulting in a “static” picture which cannot reflect adequately the underlying neurodynamic. A relatively new promising area in the study of EEG is based on reducing the signal to elementary short-term spectra of various types in accordance with the number of types of EEG stationary segments instead of using averaged power spectrum for the whole EEG. It is suggested that the various perceptual and cognitive operations associated with a mental or behavioural condition constitute a single distinguishable neurophysiological state with a distinct and reliable spectral pattern. In this case, one type of short-term spectral pattern may be considered as a single event in EEG phenomenology. To support this assumption the following issues are considered in detail: (a) the relations between local EEG short-term spectral pattern of particular type and the actual state of the neurons in underlying network and a volume conduction; (b) relationship between morphology of EEG short-term spectral pattern and the state of the underlying neurodynamical system i.e. neuronal assembly; (c) relation of different spectral pattern components to a distinct physiological mechanism; (d) relation of different spectral pattern components to different functional significance; (e) developmental changes of spectral pattern components; (f) heredity of the variance in the individual spectral pattern and its components; (g) intra-individual stability of the sets of EEG short-term spectral patterns and their percent ratio; (h) discrete dynamics of EEG short-term spectral patterns. Functional relevance (consistency) of EEG short-term spectral patterns in accordance with the changes of brain functional state

  2. EEG hemispheric asymmetry as a predictor and correlate of short-term response to clozapine treatment in schizophrenia.

    PubMed

    Knott, V; Labelle, A; Jones, B; Mahoney, C

    2000-07-01

    In search of early neuroleptic response predictors in schizophrenia, functional interhemispheric and intrahemispheric asymmetry indices, derived from spectrally analyzed resting electroencephalographic (EEG) activity, were examined in 17 schizophrenic patients prior to open label treatment with the atypical neuroleptic clozapine. Compared to EEG asymmetry indices derived from a normative data bank, patients exhibited significant interhemispheric (left greater than right) and intrahemispheric (anterior greater than posterior) deviations in delta, theta, alpha and beta frequency bands. Intrahemispheric indices were positively correlated with clinical ratings of positive symptoms and global psychopathology. Clozapine-induced improvements in positive and negative symptoms and global psychopathology symptom ratings were related to pretreatment intrahemispheric asymmetry only, with relationships varying with symptom, recording region and frequency band. The results are discussed in relation to the neurobiology of schizophrenia and the utility of EEG as an informative predictor of treatment response. PMID:10923202

  3. EEG Biofeedback as a Treatment for Substance Use Disorders: Review, Rating of Efficacy, and Recommendations for Further Research

    PubMed Central

    Cannon, Rex L.; Trudeau, David L.

    2008-01-01

    Electroencephalographic (EEG) biofeedback has been employed in substance use disorder (SUD) over the last three decades. The SUD is a complex series of disorders with frequent comorbidities and EEG abnormalities of several types. EEG biofeedback has been employed in conjunction with other therapies and may be useful in enhancing certain outcomes of therapy. Based on published clinical studies and employing efficacy criteria adapted by the Association for Applied Psychophysiology and Biofeedback and the International Society for Neurofeedback and Research, alpha theta training—either alone for alcoholism or in combination with beta training for stimulant and mixed substance abuse and combined with residential treatment programs, is probably efficacious. Considerations of further research design taking these factors into account are discussed and descriptions of contemporary research are given. PMID:18214670

  4. Automated Identification of Abnormal Adult EEGs

    PubMed Central

    López, S.; Suarez, G.; Jungreis, D.; Obeid, I.; Picone, J.

    2016-01-01

    The interpretation of electroencephalograms (EEGs) is a process that is still dependent on the subjective analysis of the examiners. Though interrater agreement on critical events such as seizures is high, it is much lower on subtler events (e.g., when there are benign variants). The process used by an expert to interpret an EEG is quite subjective and hard to replicate by machine. The performance of machine learning technology is far from human performance. We have been developing an interpretation system, AutoEEG, with a goal of exceeding human performance on this task. In this work, we are focusing on one of the early decisions made in this process – whether an EEG is normal or abnormal. We explore two baseline classification algorithms: k-Nearest Neighbor (kNN) and Random Forest Ensemble Learning (RF). A subset of the TUH EEG Corpus was used to evaluate performance. Principal Components Analysis (PCA) was used to reduce the dimensionality of the data. kNN achieved a 41.8% detection error rate while RF achieved an error rate of 31.7%. These error rates are significantly lower than those obtained by random guessing based on priors (49.5%). The majority of the errors were related to misclassification of normal EEGs. PMID:27195311

  5. Sensitivity distributions of EEG and MEG measurements.

    PubMed

    Malmivuo, J; Suihko, V; Eskola, H

    1997-03-01

    It is generally believed that because the skull has low conductivity to electric current but is transparent to magnetic fields, the measurement sensitivity of the magnetoencephalography (MEG) in the brain region should be more concentrated than that of the electroencephalography (EEG). It is also believed that the information recorded by these techniques is very different. If this were indeed the case, it might be possible to justify the cost of MEG instrumentation which is at least 25 times higher than that of EEG instrumentation. The localization of measurement sensitivity using these techniques was evaluated quantitatively in an inhomogeneous spherical head model using a new concept called half-sensitivity volume (HSV). It is shown that the planar gradiometer has a far smaller HSV than the axial gradiometer. However, using the EEG it is possible to achieve even smaller HSV's than with whole-head planar gradiometer MEG devices. The micro-superconducting quantum interference device (SQUID) MEG device does have HSV's comparable to those of the EEG. The sensitivity distribution of planar gradiometers, however, closely resembles that of dipolar EEG leads and, therefore, the MEG and EEG record the electric activity of the brain in a very similar way. PMID:9216133

  6. The octave approach to EEG analysis.

    PubMed

    Stassen, H H

    1991-10-01

    A "tonal" approach to EEG spectral analysis is presented which is compatible with the concept of physical octaves, thus providing a constant resolution of partial tones over the full frequency range inherent to human brain waves, rather than for equidistant frequency steps in the spectral domain. The specific advantages of the tonal approach, however, mainly pay off in the field of EEG sleep analysis where the interesting information is predominantly located in the lower octaves. In such cases the proposed method reveals a fine structure which displays regular maxima possessing typical properties of "overtones" within the three octaves 1-2 Hz, 2-4 Hz and 4-8 Hz. Accordingly, spectral patterns derived from tonal spectral analyses are particularly suited to measure the fine gradations of mutual differences between individual EEG sleep patterns and will therefore allow a more efficient investigation of the genetically determined proportion of sleep EEGs. On the other hand, we also tested the efficiency of tonal spectral analyses on the basis of our 5-year follow-up data of 30 healthy volunteers. It turned out that 28 persons (93.3%) could be uniquely recognized after five years by means of their EEG spectral patterns. Hence, tonal spectral analysis proved to be a powerful tool also in cases where the main EEG information is typically located in the medium octave 8-16 Hz. PMID:1762585

  7. The Significance of REM Sleep on Routine EEG.

    PubMed

    Gangadhara, Shreyas; Pizarro-Otero, Jose; Bozorg, Ali; Benbadis, Selim

    2016-03-01

    The objective of this study was to report on sleep-onset REM period (SOREMP) during routine EEG and conditions associated with it at a comprehensive epilepsy program. We retrospectively reviewed all outpatient and inpatient EEGs performed at Tampa General Hospital, a comprehensive epilepsy center over a four-month period. All EEGs were reviewed by experienced board-certified epileptologists. When SOREMP was identified, the chart was reviewed to identify the most likely etiology and the associated conditions that might be contributing. A total of 449 EEGs were reviewed between August 10, 2009, and December 9, 2009. Of those, 106 were outpatient EEGs and 343 were inpatient EEGs. There were 7 EEGs with SOREMP identified, 6 from inpatient EEGs, and 1 from an outpatient EEG. Thus, SOREMP was more common in the inpatinent setting than outpatient. There is an association of SOREMP with sleep deprivation and drug withdrawal. PMID:27180506

  8. Relation between Resting State Front-Parietal EEG Coherence and Executive Function in Parkinson's Disease

    PubMed Central

    Teramoto, Hiroko; Akimoto, Takayoshi; Shiota, Hiroshi; Kamei, Satoshi

    2016-01-01

    Objective. To assess the relation between executive dysfunction (ED) in Parkinson's disease (PD) and resting state functional connectivity evaluated using electroencephalography (EEG) coherence. Methods. Sixty-eight nondemented sporadic PD patients were assessed using the Behavioural Assessment of the Dysexecutive Syndrome (BADS) to evaluate executive function. EEG coherence in the left frontoparietal electrode pair (F3-P3) and the right frontoparietal electrode pair (F4-P4) was analyzed in the alpha and theta range. The BADS scores were compared across the coherence groups, and the multiple logistic regression analysis was performed to assess the contribution of confounders. Results. The standardized BADS score was significantly lower in the low F3-P3 coherence group in the alpha range (Mann-Whitney U test, p = 0.032), though there was no difference between F4-P4 coherence group in the alpha range, F3-P3, and F4-P4 coherence groups in the theta range and the standardized BADS score. The multiple logistic regression analysis revealed the significant relation between the F3-P3 coherence group in alpha range and age-controlled standardized BADS score (p = 0.039, 95% CI = 1.002–1.062). Conclusion. The decrease in resting state functional connectivity between the frontal and parietal cortices especially in the left side is related to ED in PD. PMID:27433473

  9. Study on Brain Dynamics by Non Linear Analysis of Music Induced EEG Signals

    NASA Astrophysics Data System (ADS)

    Banerjee, Archi; Sanyal, Shankha; Patranabis, Anirban; Banerjee, Kaushik; Guhathakurta, Tarit; Sengupta, Ranjan; Ghosh, Dipak; Ghose, Partha

    2016-02-01

    Music has been proven to be a valuable tool for the understanding of human cognition, human emotion, and their underlying brain mechanisms. The objective of this study is to analyze the effect of Hindustani music on brain activity during normal relaxing conditions using electroencephalography (EEG). Ten male healthy subjects without special musical education participated in the study. EEG signals were acquired at the frontal (F3/F4) lobes of the brain while listening to music at three experimental conditions (rest, with music and without music). Frequency analysis was done for the alpha, theta and gamma brain rhythms. The finding shows that arousal based activities were enhanced while listening to Hindustani music of contrasting emotions (romantic/sorrow) for all the subjects in case of alpha frequency bands while no significant changes were observed in gamma and theta frequency ranges. It has been observed that when the music stimulus is removed, arousal activities as evident from alpha brain rhythms remain for some time, showing residual arousal. This is analogous to the conventional 'Hysteresis' loop where the system retains some 'memory' of the former state. This is corroborated in the non linear analysis (Detrended Fluctuation Analysis) of the alpha rhythms as manifested in values of fractal dimension. After an input of music conveying contrast emotions, withdrawal of music shows more retention as evidenced by the values of fractal dimension.

  10. Asynchronous detection of kinesthetic attention during mobilization of lower limbs using EEG measurements

    NASA Astrophysics Data System (ADS)

    Melinscak, Filip; Montesano, Luis; Minguez, Javier

    2016-02-01

    Objective. Attention is known to modulate the plasticity of the motor cortex, and plasticity is crucial for recovery in motor rehabilitation. This study addresses the possibility of using an EEG-based brain-computer interface (BCI) to detect kinesthetic attention to movement. Approach. A novel experiment emulating physical rehabilitation was designed to study kinesthetic attention. The protocol involved continuous mobilization of lower limbs during which participants reported levels of attention to movement—from focused kinesthetic attention to mind wandering. For this protocol an asynchronous BCI detector of kinesthetic attention and deliberate mind wandering was designed. Main results. EEG analysis showed significant differences in theta, alpha, and beta bands, related to the attentional state. These changes were further pinpointed to bands relative to the frequency of the individual alpha peak. The accuracy of the designed BCI ranged between 60.8% and 68.4% (significantly above chance level), depending on the used analysis window length, i.e. acceptable detection delay. Significance. This study shows it is possible to use self-reporting to study attention-related changes in EEG during continuous mobilization. Such a protocol is used to develop an asynchronous BCI detector of kinesthetic attention, with potential applications to motor rehabilitation.

  11. Clinical Development and Implementation of an Institutional Guideline for Prospective EEG Monitoring and Reporting of Delayed Cerebral Ischemia.

    PubMed

    Muniz, Carlos F; Shenoy, Apeksha V; OʼConnor, Kathryn L; Bechek, Sophia C; Boyle, Emily J; Guanci, Mary M; Tehan, Tara M; Zafar, Sahar F; Cole, Andrew J; Patel, Aman B; Westover, Michael B; Rosenthal, Eric S

    2016-06-01

    Delayed cerebral ischemia (DCI) is the most common and disabling complication among patients admitted to the hospital for subarachnoid hemorrhage (SAH). Clinical and radiographic methods often fail to detect DCI early enough to avert irreversible injury. We assessed the clinical feasibility of implementing a continuous EEG (cEEG) ischemia monitoring service for early DCI detection as part of an institutional guideline. An institutional neuromonitoring guideline was designed by an interdisciplinary team of neurocritical care, clinical neurophysiology, and neurosurgery physicians and nursing staff and cEEG technologists. The interdisciplinary team focused on (1) selection criteria of high-risk patients, (2) minimization of safety concerns related to prolonged monitoring, (3) technical selection of quantitative and qualitative neurophysiologic parameters based on expert consensus and review of the literature, (4) a structured interpretation and reporting methodology, prompting direct patient evaluation and iterative neurocritical care, and (5) a two-layered quality assurance process including structured clinician interviews assessing events of neurologic worsening and an adjudicated consensus review of neuroimaging and medical records. The resulting guideline's clinical feasibility was then prospectively evaluated. The institutional SAH monitoring guideline used transcranial Doppler ultrasound and cEEG monitoring for vasospasm and ischemia monitoring in patients with either Fisher group 3 or Hunt-Hess grade IV or V SAH. Safety criteria focused on prevention of skin breakdown and agitation. Technical components included monitoring of transcranial Doppler ultrasound velocities and cEEG features, including quantitative alpha:delta ratio and percent alpha variability, qualitative evidence of new focal slowing, late-onset epileptiform activity, or overall worsening of background. Structured cEEG reports were introduced including verbal communication for findings concerning

  12. Time course of EEG oscillations during repeated listening of a well-known aria.

    PubMed

    Jäncke, Lutz; Kühnis, Jürg; Rogenmoser, Lars; Elmer, Stefan

    2015-01-01

    While previous studies have analyzed mean neurophysiological responses to musical stimuli, the current study aimed to identify specific time courses of electroencephalography (EEG) oscillations, which are associated with dynamic changes in the acoustic features of the musical stimulus. In addition, we were interested in whether these time courses change during a repeated presentation of the same musical piece. A total of 16 subjects repeatedly listened to the well-known aria "Nessun dorma," sung by Paul Potts, while continuous 128-channel EEG and heart rate, as well as electrodermal responses, were recorded. The time courses for the EEG oscillations were calculated using a time resolution of 1 second for several frequency bands, on the basis of individual alpha-peak frequencies (theta, low alpha-1, low alpha-2, upper alpha, and beta). For all frequency bands, we identified a more or less continuous increase in power relative to a baseline period, indicating strong event-related synchronization (ERS) during music listening. The ERS time courses, however, did not correlate strongly with the time courses of the acoustic features of the aria. In addition, we did not observe changes in EEG oscillations after repeated presentation of the same musical piece. Aside from this distinctive feature, we identified a remarkable variability in EEG oscillations, both within and between the repeated presentations of the aria. We interpret the continuous increase in ERS observed in all frequency bands during music listening as an indicator of a particular neurophysiological and psychological state evoked by music listening. We suggest that this state is characterized by increased internal attention (accompanied by reduced external attention), increased inhibition of brain networks not involved in the generation of this internal state, the maintenance of a particular level of general alertness, and a type of brain state that can be described as "mind wandering." The overall state can

  13. Time course of EEG oscillations during repeated listening of a well-known aria

    PubMed Central

    Jäncke, Lutz; Kühnis, Jürg; Rogenmoser, Lars; Elmer, Stefan

    2015-01-01

    While previous studies have analyzed mean neurophysiological responses to musical stimuli, the current study aimed to identify specific time courses of electroencephalography (EEG) oscillations, which are associated with dynamic changes in the acoustic features of the musical stimulus. In addition, we were interested in whether these time courses change during a repeated presentation of the same musical piece. A total of 16 subjects repeatedly listened to the well-known aria “Nessun dorma,” sung by Paul Potts, while continuous 128-channel EEG and heart rate, as well as electrodermal responses, were recorded. The time courses for the EEG oscillations were calculated using a time resolution of 1 second for several frequency bands, on the basis of individual alpha-peak frequencies (theta, low alpha-1, low alpha-2, upper alpha, and beta). For all frequency bands, we identified a more or less continuous increase in power relative to a baseline period, indicating strong event-related synchronization (ERS) during music listening. The ERS time courses, however, did not correlate strongly with the time courses of the acoustic features of the aria. In addition, we did not observe changes in EEG oscillations after repeated presentation of the same musical piece. Aside from this distinctive feature, we identified a remarkable variability in EEG oscillations, both within and between the repeated presentations of the aria. We interpret the continuous increase in ERS observed in all frequency bands during music listening as an indicator of a particular neurophysiological and psychological state evoked by music listening. We suggest that this state is characterized by increased internal attention (accompanied by reduced external attention), increased inhibition of brain networks not involved in the generation of this internal state, the maintenance of a particular level of general alertness, and a type of brain state that can be described as “mind wandering.” The overall

  14. alpha-Thalassaemia in Tunisia: some epidemiological and molecular data.

    PubMed

    Siala, H; Ouali, F; Messaoud, T; Bibi, A; Fattoum, S

    2008-12-01

    Unlike the other haemoglobinopathies, few researches have been published concerning alpha-thalassaemia in Tunisia. The aim of the present work is to acquire further data concerning alpha-thalassaemia prevalence and molecular defects spectrum in Tunisia, by collecting and studying several kinds of samples carrying alpha-thalassaemia. The first survey conducted on 529 cord blood samples using cellulose acetate electrophoresis, have displayed the prevalence of 7.38% Hb Bart's carriers at birth. Molecular analyses were conducted by PCR and DNA sequencing on 20 families' cases from the above survey carrying the Hb Bart's at birth and on 10 Hb H diseased patients. The results showed six alpha-globin gene molecular defects and were responsible for alpha-thalassaemia: -alpha(3.7), - -(MedI), alpha(TSaudi), alpha(2)(cd23GAG->Stop), Hb Greone Hart: alpha(1)(119CCT->TCT) corresponding to 11 genotypes out of which two are responsible for Hb H disease (- -(Med)/-alpha(3.7)) and (alpha(TSaudi)alpha/alpha(TSaudi)alpha) and a newly described polymorphism: alpha+6C->G. The geographical repartition of alpha-thal carriers showed that the -alpha3.7 deletion is distributed all over the country, respectively the alpha(HphI) and alpha(TSaudi) seem to be more frequent in the central region of the northeast region. The haematological and clinical data showed a moderate phenotype with a late age of diagnosis for Hb H disease. This work had permitted, in addition to an overview on alpha-thalassaemia in the country, the optimization of protocols for alpha-thalassaemia detection in our lab, allowing further investigations concerning phenotype-genotype correlation in sickle cell disease or beta-thalassaemia. PMID:19147907

  15. Distribution entropy analysis of epileptic EEG signals.

    PubMed

    Li, Peng; Yan, Chang; Karmakar, Chandan; Liu, Changchun

    2015-08-01

    It is an open-ended challenge to accurately detect the epileptic seizures through electroencephalogram (EEG) signals. Recently published studies have made elaborate attempts to distinguish between the normal and epileptic EEG signals by advanced nonlinear entropy methods, such as the approximate entropy, sample entropy, fuzzy entropy, and permutation entropy, etc. Most recently, a novel distribution entropy (DistEn) has been reported to have superior performance compared with the conventional entropy methods for especially short length data. We thus aimed, in the present study, to show the potential of DistEn in the analysis of epileptic EEG signals. The publicly-accessible Bonn database which consisted of normal, interictal, and ictal EEG signals was used in this study. Three different measurement protocols were set for better understanding the performance of DistEn, which are: i) calculate the DistEn of a specific EEG signal using the full recording; ii) calculate the DistEn by averaging the results for all its possible non-overlapped 5 second segments; and iii) calculate it by averaging the DistEn values for all the possible non-overlapped segments of 1 second length, respectively. Results for all three protocols indicated a statistically significantly increased DistEn for the ictal class compared with both the normal and interictal classes. Besides, the results obtained under the third protocol, which only used very short segments (1 s) of EEG recordings showed a significantly (p <; 0.05) increased DistEn for the interictal class in compassion with the normal class, whereas both analyses using relatively long EEG signals failed in tracking this difference between them, which may be due to a nonstationarity effect on entropy algorithm. The capability of discriminating between the normal and interictal EEG signals is of great clinical relevance since it may provide helpful tools for the detection of a seizure onset. Therefore, our study suggests that the Dist

  16. Ordinal patterns in epileptic brains: Analysis of intracranial EEG and simultaneous EEG-fMRI

    NASA Astrophysics Data System (ADS)

    Rummel, C.; Abela, E.; Hauf, M.; Wiest, R.; Schindler, K.

    2013-06-01

    Epileptic seizures are associated with high behavioral stereotypy of the patients. In the EEG of epilepsy patients characteristic signal patterns can be found during and between seizures. Here we use ordinal patterns to analyze EEGs of epilepsy patients and quantify the degree of signal determinism. Besides relative signal redundancy and the fraction of forbidden patterns we introduce the fraction of under-represented patterns as a new measure. Using the logistic map, parameter scans are performed to explore the sensitivity of the measures to signal determinism. Thereafter, application is made to two types of EEGs recorded in two epilepsy patients. Intracranial EEG shows pronounced determinism peaks during seizures. Finally, we demonstrate that ordinal patterns may be useful for improving analysis of non-invasive simultaneous EEG-fMRI.

  17. [INTERHEMISPHERIC DIFFERENCES BETWEEN ENCEPHALOGRAPHY ALPHA SPECTRAL POWER INDICES DURING BICYCLE ERGOMETRY].

    PubMed

    Pasekova, O B; Stepanova, G P; Voronkov, Yu I

    2015-01-01

    The EEG recording from 30 supine volunterrs during bicycle ergometry with the load growing incrementally to a submaximal heart rate was made in order to study alpha spectra and their interhemispheric differences. Comparative analysis of EEG records demonstrated a statistical gain of the alpha-power in both hemispheres at the final step of aerobic work and throughout the period of recovery with power reaching the highest values in the left hemisphere. Analysis of interhemispheric differences points to activation of the right hemisphere over the whole period of the investigation. PMID:26738303

  18. Sex differences between the combined and inattentive types of attention-deficit/hyperactivity disorder: an EEG perspective.

    PubMed

    Dupuy, Franca E; Barry, Robert J; Clarke, Adam R; McCarthy, Rory; Selikowitz, Mark

    2013-09-01

    This study investigated sex differences between the EEGs of Combined and Inattentive types of attention-deficit/hyperactivity disorder (AD/HD) within boys and girls aged 8-12 years. Subject groups included 80 AD/HD Combined type (40 boys and 40 girls), 80 AD/HD Inattentive type (40 boys and 40 girls) and 80 controls (40 boys and 40 girls). An eyes-closed resting EEG was recorded and Fourier transformed to provide estimates for absolute and relative power in the delta, theta, alpha and beta frequency bands, as well as total power and the theta/beta ratio. The boy AD/HD groups, compared with boy controls, had greater absolute and relative theta, greater theta/beta ratio, reduced absolute and relative alpha, and reduced absolute and relative beta. The girl AD/HD groups, compared with girl controls, had greater absolute delta, greater absolute and relative theta, greater theta/beta ratio, greater total power, and reduced relative delta and relative beta. Between AD/HD types, Combined type boys had globally greater absolute and relative theta, greater theta/beta ratio, and less relative alpha than Inattentive type boys. While topographical differences emerged, there were no significant global differences between AD/HD types in girls. That is, EEG differences between AD/HD types are dissimilar in boys and girls. Different EEG maturational patterns between boys and girls also obscure AD/HD-related EEG abnormalities. These results have important implications for our understanding of AD/HD in girls. Ignoring such sex differences may have compromised the value of previous AD/HD investigations, and these sex differences should be recognised in future research. PMID:23603052

  19. Effects of sweet and bitter gustatory stimuli in anorexia nervosa on EEG frequency spectra.

    PubMed

    Tóth, Erika; Túry, Ferenc; Gáti, Agnes; Weisz, Júlia; Kondákor, István; Molnár, Márk

    2004-05-01

    The possible differences in processing gustatory stimuli in anorexic patients compared to healthy control subjects was investigated by electrophysiological methods. The electroencephalogram (EEG) was recorded in outpatients treated with anorexia nervosa (AN) and age-matched controls after exposure to sweet (milk chocolate) and bitter (black tea) taste stimuli. Power spectrum analysis was performed on EEG epochs recorded in the above conditions. Compared to controls a significantly higher percent of theta, and lower percent of alpha1 band power was found in anorexic patients, irrespective of the kind of taste effects and hemispheric side. The pattern of activation caused by sweet and bitter stimuli was found to be different in these two groups, possibly indicating altered gustatory processing mechanisms in AN. PMID:15094251

  20. Manual Lymph Drainage Attenuates Frontal EEG Asymmetry in Subjects with Psychological Stress: A Preliminary Study

    PubMed Central

    Shim, Jung-Myo; Kim, Sung-Joong

    2014-01-01

    [Purpose] The purpose of this preliminary study was to investigate the effect of manual lymph drainage (MLD) of the neck on frontal electroencephalogram (EEG) asymmetry in subjects with psychological stress. [Subjects] Thirteen subjects with psychological stress participated in the study. [Methods] Subjects received MLD of the neck for 15 min. [Results] Analysis of the frontal asymmetry index showed that the energy shift in the alpha frequency band from the left hemisphere to the right hemisphere after MLD resulted in greater left-side activation (positive asymmetry values), which could be related to the positive emotional state observed particularly in the F7–F8 area. [Conclusion] These preliminary findings suggest that frontal EEG asymmetry was significantly attenuated after MLD. PMID:24764627

  1. Effect of immobilization on the EEG of the baboon. Comparison with telemetry results from unrestricted animals

    NASA Technical Reports Server (NTRS)

    Bert, J.; Collomb, H.

    1980-01-01

    The EEG of the baboon was studied under two very different sets of conditions: 37 were totally immobolized while 12 were studied in their free movements with 4 channel telemetry. For the immobilzed, 3 stages were described: (1) activation, record desynchronized; (2) rest with 13-15 cm/sec rhythm, like the human alpha rhythm stage but with eyes open or closed; (3)relaxation with a decrease in 13-15 rhythm and the appearance of 5-7 cm/sec theta waves, eyelids closed, animal apparently sleeping. For the free animals the rest stage appeared when the animal's attention was not directed anywhere and there was no relaxation stage. It is concluded that the EEG pattern of the immobilized animal that was described as the "relaxation" stage really represents a special functional state which one must distinguish clearly from the physiological stages of sleep.

  2. Integrative Frequency Power of EEG Correlates with Progression of Mild Cognitive Impairment to Dementia in Parkinson's Disease.

    PubMed

    Gu, Youquan; Chen, Jun; Lu, Yaqin; Pan, Suyue

    2016-04-01

    Clinically, predicting the progression of mild cognitive impairment (MCI) and diagnosing dementia in Parkinson's disease (PD) are difficult. This study aims to explore an integrative electroencephalography (EEG) frequency power that could be used to predict the progression of MCI in PD patients. Twenty-six PD patients, in this study, were divided into the mild cognitive impairment group (PDMCI, 17 patients) and dementia group (PDD, 9 patients) according to cognitive performance. Beta peak frequency, alpha relative power, and alpha/theta power were recorded and analyzed for the prediction. Mini Mental State Examination (MMSE) scores at initiation, in the first year, and in the second year were examined. The sensitivity, specificity, positive predictive value, Matthew correlation coefficient, and positive likelihood ratio were calculated in both the integrative EEG biomarkers and single best biomarker. Of the 17 patients with MCI for 2 years, 6 progressed to dementia. Integrative EEG biomarkers, mainly associated with beta peak frequency, can predict conversion from MCI to dementia. These biomarkers had sensitivity of 82% and specificity of 78%, compared with sensitivity of 61% and specificity of 58% of the beta peak frequency. In conclusion, the integrative EEG frequency powers were more sensitive and specific to MCI progression in PD patients. PMID:25519446

  3. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    PubMed Central

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-01-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress. PMID:26286628

  4. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    NASA Astrophysics Data System (ADS)

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-08-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress.

  5. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization.

    PubMed

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-01-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress. PMID:26286628

  6. Electrical stimulation of the frontal cortex enhances slow-frequency EEG activity and sleepiness.

    PubMed

    D'Atri, A; De Simoni, E; Gorgoni, M; Ferrara, M; Ferlazzo, F; Rossini, P M; De Gennaro, L

    2016-06-01

    Our aim was to enhance the spontaneous slow-frequency EEG activity during the resting state using oscillating transcranial direct currents (tDCS) with a stimulation frequency that resembles the spontaneous oscillations of sleep onset. Accordingly, in this preliminary study, we assessed EEG after-effects of a frontal oscillatory tDCS with different frequency (0.8 vs. 5Hz) and polarity (anodal, cathodal, and sham). Two single-blind experiments compared the after effects on the resting EEG of oscillatory tDCS [Exp. 1=0.8Hz, 10 subjects (26.2±2.5years); Exp. 2=5Hz, 10 subjects (27.4±2.4years)] by manipulating its polarity. EEG signals recorded (28 scalp derivations) before and after stimulation [slow oscillations (0.5-1Hz), delta (1-4Hz), theta (5-7Hz), alpha (8-12Hz), beta 1 (13-15Hz) and beta 2 (16-24Hz)] were compared between conditions as a function of polarity (anodal vs. cathodal vs. sham) and frequency of stimulation (0.8 vs. 5Hz). We found a significant relative enhancement of the delta activity after the anodal tDCS at 5Hz compared to that at 0.8Hz. This increase, even though not reaching the statistical significance compared to sham, is concomitant to a significant increase of subjective sleepiness, as assessed by a visual analog scale. These two phenomena are linearly related with a regional specificity, correlations being restricted to cortical areas perifocal to the stimulation site. We have shown that a frontal oscillating anodal tDCS at 5Hz results in an effective change of both subjective sleepiness and spontaneous slow-frequency EEG activity. These changes are critically associated to both stimulation polarity (anodal) and frequency (5Hz). However, evidence of frequency-dependence seems more unequivocal than evidence of polarity-dependence. PMID:26964682

  7. Estimation of Eye Closure Degree Using EEG Sensors and Its Application in Driver Drowsiness Detection

    PubMed Central

    Li, Gang; Chung, Wan-Young

    2014-01-01

    Currently, driver drowsiness detectors using video based technology is being widely studied. Eyelid closure degree (ECD) is the main measure of the video-based methods, however, drawbacks such as brightness limitations and practical hurdles such as distraction of the drivers limits its success. This study presents a way to compute the ECD using EEG sensors instead of video-based methods. The premise is that the ECD exhibits a linear relationship with changes of the occipital EEG. A total of 30 subjects are included in this study: ten of them participated in a simple proof-of-concept experiment to verify the linear relationship between ECD and EEG, and then twenty participated in a monotonous highway driving experiment in a driving simulator environment to test the robustness of the linear relationship in real-life applications. Taking the video-based method as a reference, the Alpha power percentage from the O2 channel is found to be the best input feature for linear regression estimation of the ECD. The best overall squared correlation coefficient (SCC, denoted by r2) and mean squared error (MSE) validated by linear support vector regression model and leave one subject out method is r2 = 0.930 and MSE = 0.013. The proposed linear EEG-ECD model can achieve 87.5% and 70.0% accuracy for male and female subjects, respectively, for a driver drowsiness application, percentage eyelid closure over the pupil over time (PERCLOS). This new ECD estimation method not only addresses the video-based method drawbacks, but also makes ECD estimation more computationally efficient and easier to implement in EEG sensors in a real time way. PMID:25237899

  8. Time-varying bispectral analysis of visually evoked multi-channel EEG

    NASA Astrophysics Data System (ADS)

    Chandran, Vinod

    2012-12-01

    Theoretical foundations of higher order spectral analysis are revisited to examine the use of time-varying bicoherence on non-stationary signals using a classical short-time Fourier approach. A methodology is developed to apply this to evoked EEG responses where a stimulus-locked time reference is available. Short-time windowed ensembles of the response at the same offset from the reference are considered as ergodic cyclostationary processes within a non-stationary random process. Bicoherence can be estimated reliably with known levels at which it is significantly different from zero and can be tracked as a function of offset from the stimulus. When this methodology is applied to multi-channel EEG, it is possible to obtain information about phase synchronization at different regions of the brain as the neural response develops. The methodology is applied to analyze evoked EEG response to flash visual stimulii to the left and right eye separately. The EEG electrode array is segmented based on bicoherence evolution with time using the mean absolute difference as a measure of dissimilarity. Segment maps confirm the importance of the occipital region in visual processing and demonstrate a link between the frontal and occipital regions during the response. Maps are constructed using bicoherence at bifrequencies that include the alpha band frequency of 8Hz as well as 4 and 20Hz. Differences are observed between responses from the left eye and the right eye, and also between subjects. The methodology shows potential as a neurological functional imaging technique that can be further developed for diagnosis and monitoring using scalp EEG which is less invasive and less expensive than magnetic resonance imaging.

  9. Odds Ratio Product of Sleep EEG as a Continuous Measure of Sleep State

    PubMed Central

    Younes, Magdy; Ostrowski, Michele; Soiferman, Marc; Younes, Henry; Younes, Mark; Raneri, Jill; Hanly, Patrick

    2015-01-01

    Study Objectives: To develop and validate an algorithm that provides a continuous estimate of sleep depth from the electroencephalogram (EEG). Design: Retrospective analysis of polysomnograms. Setting: Research laboratory. Participants: 114 patients who underwent clinical polysomnography in sleep centers at the University of Manitoba (n = 58) and the University of Calgary (n = 56). Interventions: None. Measurements and Results: Power spectrum of EEG was determined in 3-second epochs and divided into delta, theta, alpha-sigma, and beta frequency bands. The range of powers in each band was divided into 10 aliquots. EEG patterns were assigned a 4-digit number that reflects the relative power in the 4 frequency ranges (10,000 possible patterns). Probability of each pattern occurring in 30-s epochs staged awake was determined, resulting in a continuous probability value from 0% to 100%. This was divided by 40 (% of epochs staged awake) producing the odds ratio product (ORP), with a range of 0–2.5. In validation testing, average ORP decreased progressively as EEG progressed from wakefulness (2.19 ± 0.29) to stage N3 (0.13 ± 0.05). ORP < 1.0 predicted sleep and ORP > 2.0 predicted wakefulness in > 95% of 30-s epochs. Epochs with intermediate ORP occurred in unstable sleep with a high arousal index (> 70/h) and were subject to much interrater scoring variability. There was an excellent correlation (r2 = 0.98) between ORP in current 30-s epochs and the likelihood of arousal or awakening occurring in the next 30-s epoch. Conclusions: Our results support the use of the odds ratio product (ORP) as a continuous measure of sleep depth. Citation: Younes M, Ostrowski M, Soiferman M, Younes H, Younes M, Raneri J, Hanly P. Odds ratio product of sleep EEG as a continuous measure of sleep state. SLEEP 2015;38(4):641–654. PMID:25348125

  10. Inter-hemispheric EEG coherence analysis in Parkinson's disease: assessing brain activity during emotion processing.

    PubMed

    Yuvaraj, R; Murugappan, M; Ibrahim, Norlinah Mohamed; Sundaraj, Kenneth; Omar, Mohd Iqbal; Mohamad, Khairiyah; Palaniappan, R; Satiyan, M

    2015-02-01

    Parkinson's disease (PD) is not only characterized by its prominent motor symptoms but also associated with disturbances in cognitive and emotional functioning. The objective of the present study was to investigate the influence of emotion processing on inter-hemispheric electroencephalography (EEG) coherence in PD. Multimodal emotional stimuli (happiness, sadness, fear, anger, surprise, and disgust) were presented to 20 PD patients and 30 age-, education level-, and gender-matched healthy controls (HC) while EEG was recorded. Inter-hemispheric coherence was computed from seven homologous EEG electrode pairs (AF3-AF4, F7-F8, F3-F4, FC5-FC6, T7-T8, P7-P8, and O1-O2) for delta, theta, alpha, beta, and gamma frequency bands. In addition, subjective ratings were obtained for a representative of emotional stimuli. Interhemispherically, PD patients showed significantly lower coherence in theta, alpha, beta, and gamma frequency bands than HC during emotion processing. No significant changes were found in the delta frequency band coherence. We also found that PD patients were more impaired in recognizing negative emotions (sadness, fear, anger, and disgust) than relatively positive emotions (happiness and surprise). Behaviorally, PD patients did not show impairment in emotion recognition as measured by subjective ratings. These findings suggest that PD patients may have an impairment of inter-hemispheric functional connectivity (i.e., a decline in cortical connectivity) during emotion processing. This study may increase the awareness of EEG emotional response studies in clinical practice to uncover potential neurophysiologic abnormalities. PMID:24894699

  11. Attention and Working Memory-Related EEG Markers of Subtle Cognitive Deterioration in Healthy Elderly Individuals.

    PubMed

    Deiber, Marie-Pierre; Meziane, Hadj Boumediene; Hasler, Roland; Rodriguez, Cristelle; Toma, Simona; Ackermann, Marine; Herrmann, François; Giannakopoulos, Panteleimon

    2015-01-01

    Future treatments of Alzheimer's disease need the identification of cases at high risk at the preclinical stage of the disease before the development of irreversible structural damage. We investigated here whether subtle cognitive deterioration in a population of healthy elderly individuals could be predicted by EEG signals at baseline under cognitive activation. Continuous EEG was recorded in 97 elderly control subjects and 45 age-matched mild cognitive impairment (MCI) cases during a simple attentional and a 2-back working memory task. Upon 18-month neuropsychological follow-up, the final sample included 55 stable (sCON) and 42 deteriorated (dCON) controls. We examined the P1, N1, P3, and PNwm event-related components as well as the oscillatory activities in the theta (4-7 Hz), alpha (8-13 Hz), and beta (14-25 Hz) frequency ranges (ERD/ERS: event-related desynchronization/synchronization, and ITC: inter-trial coherence). Behavioral performance, P1, and N1 components were comparable in all groups. The P3, PNwm, and all oscillatory activity indices were altered in MCI cases compared to controls. Only three EEG indices distinguished the two control groups: alpha and beta ERD (dCON >  sCON) and beta ITC (dCON <  sCON). These findings show that subtle cognitive deterioration has no impact on EEG indices associated with perception, discrimination, and working memory processes but mostly affects attention, resulting in an enhanced recruitment of attentional resources. In addition, cognitive decline alters neural firing synchronization at high frequencies (14-25 Hz) at early stages, and possibly affects lower frequencies (4-13 Hz) only at more severe stages. PMID:26401557

  12. Sharp Slow Waves in the EEG.

    PubMed

    Janati, A Bruce; AlGhasab, Naif Saad; Alshammari, Raed Ayed; saad AlGhassab, Abdulmohsen; Al-Aslami Yossef Fahad

    2016-06-01

    There exists a paucity of data in the EEG literature on characteristics of "atypical" interictal epileptiform discharges (IEDs), including sharp slow waves (SSWs). This article aims to address the clinical, neurophysiological, and neuropathological significance of SSW The EEGs of 920 patients at a tertiary-care facility were prospectively reviewed over a period of one year. Thirty-six patients had SSWs in their EEG. Of these, 6 patients were excluded because of inadequate clinical data. The clinical and neuroimaging data of the remaining 30 patients were then retrospectively collected and reviewed, and the findings were correlated. The data revealed that SSWs were rare and age-related EEG events occurring primarily in the first two decades of life. All patients with SSWs had documented epilepsy, presenting clinically with partial or generalized epilepsy. It is notable that one-third of the patients with SSWs had chronic or static central nervous system (CNS) pathology, particularly congenital CNS anomalies. Though more than one mechanism may be involved in the pathogenesis of SSWs, this research indicates that the most compelling theory is a deeply seated cortical generator giving rise to this EEG pattern. The presence of SSWs should alert clinicians to the presence of partial or generalized epilepsy or an underlying chronic or static CNS pathology, in particular congenital CNS anomalies, underscoring the significance of brain magnetic resonance imaging in the work-up of this population. PMID:27373055

  13. Transcranial direct current stimulation and power spectral parameters: a tDCS/EEG co-registration study

    PubMed Central

    Mangia, Anna L.; Pirini, Marco; Cappello, Angelo

    2014-01-01

    Transcranial direct current stimulation (tDCS) delivers low electric currents to the brain through the scalp. Constant electric currents induce shifts in neuronal membrane excitability, resulting in secondary changes in cortical activity. Concomitant electroencephalography (EEG) monitoring during tDCS can provide valuable information on the tDCS mechanisms of action. This study examined the effects of anodal tDCS on spontaneous cortical activity in a resting brain to disclose possible modulation of spontaneous oscillatory brain activity. EEG activity was measured in ten healthy subjects during and after a session of anodal stimulation of the postero-parietal cortex to detect the tDCS-induced alterations. Changes in the theta, alpha, beta, and gamma power bands were investigated. Three main findings emerged: (1) an increase in theta band activity during the first minutes of stimulation; (2) an increase in alpha and beta power during and after stimulation; (3) a widespread activation in several brain regions. PMID:25147519

  14. Resting-State EEG Delta Power is Associated with Psychological Pain in Adults with a History of Depression

    PubMed Central

    Meerwijk, Esther L.; Ford, Judith M.; Weiss, Sandra J.

    2015-01-01

    Psychological pain is a prominent symptom of clinical depression. We asked if frontal alpha asymmetry, frontal EEG power, and frontal fractal dimension asymmetry predicted psychological pain in adults with a history of depression. Resting-state frontal EEG (F3/F4) was recorded while participants (N=35) sat upright with their eyes closed. Frontal delta power predicted psychological pain while controlling for depressive symptoms, with participants who exhibited less power experiencing greater psychological pain. Frontal fractal dimension asymmetry, a nonlinear measure of complexity, also predicted psychological pain, such that greater left than right complexity was associated with greater psychological pain. Frontal alpha asymmetry did not contribute unique variance to any regression model of psychological pain. As resting-state delta power is associated with the brain’s default mode network, results suggest that the default mode network was less activated during high psychological pain. Findings are consistent with a state of arousal associated with psychological pain. PMID:25600291

  15. Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search

    PubMed Central

    Müller, Notger G.; Vellage, Anne-Katrin; Heinze, Hans-Jochen; Zaehle, Tino

    2015-01-01

    The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects. PMID:26606255

  16. Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search.

    PubMed

    Müller, Notger G; Vellage, Anne-Katrin; Heinze, Hans-Jochen; Zaehle, Tino

    2015-01-01

    The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects. PMID:26606255

  17. Spectral modulation of frontal EEG during motor skill acquisition: a mobile EEG study.

    PubMed

    Wong, Savio W H; Chan, Rosa H M; Mak, Joseph N

    2014-01-01

    This study investigates the modulation of frontal EEG dynamics with respect to progress in motor skill acquisition using a wireless EEG system with a single dry sensor. Participants were required to complete repeated trials of a computerized visual-motor task similar to mirror drawing while the EEG was collected. In each trial, task performance of the participants was summarized with a familiarity index which took into account the performance accuracy, completion rate and time. Our findings demonstrated that certain EEG power spectra decreased with an increase in motor task familiarity. In particular, frontal EEG activities in delta and theta bands of the whole trial and in gamma band in the middle of the trial are having a significant negative relationship with the overall familiarity level of the task. The findings suggest that frontal EEG spectra are significantly modulated during motor skill acquisition. Results of this study shed light on the possibility of simultaneous monitoring of brain activity during an unconstrained natural task with a single dry sensor mobile EEG in an everyday environment. PMID:24095979

  18. Exploring miniaturized EEG electrodes for brain-computer interfaces. An EEG you do not see?

    PubMed

    Bleichner, Martin G; Lundbeck, Micha; Selisky, Matthias; Minow, Falk; Jäger, Manuela; Emkes, Reiner; Debener, Stefan; De Vos, Maarten

    2015-04-01

    Electroencephalography (EEG) allows the study of the brain-behavior relationship in humans. Most of what we have learned with EEG was through observing the brain-behavior relationship under well-controlled laboratory conditions. However, by reducing "normal" behavior to a minimum the ecological validity of the results can be limited. Recent developments toward mobile EEG solutions allow to study the brain-behavior relationship outside the laboratory in more natural situations. Besides mobility and robustness with respect to motion, mobile EEG systems should also interfere as little as possible with the participant's behavior. For example, natural interaction with other people could be hindered when it is obvious that a participant wears an EEG cap. This study evaluates the signal quality obtained with an unobtrusive solution for EEG monitoring through the integration of miniaturized EEG ton-electrodes into both a discreet baseball cap and an individualized ear piece. We show that such mini electrodes located at scalp and ear locations can reliably record event related potentials in a P300 brain-computer-interface application. PMID:25847919

  19. Exploring miniaturized EEG electrodes for brain-computer interfaces. An EEG you do not see?

    PubMed Central

    Bleichner, Martin G; Lundbeck, Micha; Selisky, Matthias; Minow, Falk; Jäger, Manuela; Emkes, Reiner; Debener, Stefan; De Vos, Maarten

    2015-01-01

    Electroencephalography (EEG) allows the study of the brain–behavior relationship in humans. Most of what we have learned with EEG was through observing the brain–behavior relationship under well-controlled laboratory conditions. However, by reducing “normal” behavior to a minimum the ecological validity of the results can be limited. Recent developments toward mobile EEG solutions allow to study the brain–behavior relationship outside the laboratory in more natural situations. Besides mobility and robustness with respect to motion, mobile EEG systems should also interfere as little as possible with the participant's behavior. For example, natural interaction with other people could be hindered when it is obvious that a participant wears an EEG cap. This study evaluates the signal quality obtained with an unobtrusive solution for EEG monitoring through the integration of miniaturized EEG ton-electrodes into both a discreet baseball cap and an individualized ear piece. We show that such mini electrodes located at scalp and ear locations can reliably record event related potentials in a P300 brain–computer–interface application. PMID:25847919

  20. EEG Monitoring in Cerebral Ischemia: Basic Concepts and Clinical Applications.

    PubMed

    van Putten, Michel J A M; Hofmeijer, Jeannette

    2016-06-01

    EEG is very sensitive to changes in neuronal function resulting from ischemia. The authors briefly review essentials of EEG generation and the effects of ischemia on the underlying neuronal processes. They discuss the differential sensitivity of various neuronal processes to energy limitations, including synaptic disturbances. The clinical applications reviewed include continuous EEG monitoring during carotid surgery and acute ischemic stroke, and EEG monitoring for prognostication after cardiac arrest. PMID:27258443

  1. Alpha-1 Antitrypsin Deficiency

    MedlinePlus

    ... Liver Disease Information > Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency Explore this section to learn more about alpha-1 antitrypsin deficiency, including a description of the disorder ...

  2. Alpha oscillatory correlates of motor inhibition in the aged brain

    PubMed Central

    Bönstrup, Marlene; Hagemann, Julian; Gerloff, Christian; Sauseng, Paul; Hummel, Friedhelm C.

    2015-01-01

    Exerting inhibitory control is a cognitive ability mediated by functions known to decline with age. The goal of this study is to add to the mechanistic understanding of cortical inhibition during motor control in aged brains. Based on behavioral findings of impaired inhibitory control with age we hypothesized that elderly will show a reduced or a lack of EEG alpha-power increase during tasks that require motor inhibition. Since inhibitory control over movements has been shown to rely on prior motor memory formation, we investigated cortical inhibitory processes at two points in time—early after learning and after an overnight consolidation phase and hypothesized an overnight increase of inhibitory capacities. Young and elderly participants acquired a complex finger movement sequence and in each experimental session brain activity during execution and inhibition of the sequence was recorded with multi-channel EEG. We assessed cortical processes of sustained inhibition by means of task-induced changes of alpha oscillatory power. During inhibition of the learned movement, young participants showed a significant alpha power increase at the sensorimotor cortices whereas elderly did not. Interestingly, for both groups, the overnight consolidation phase improved up-regulation of alpha power during sustained inhibition. This points to deficits in the generation and enhancement of local inhibitory mechanisms at the sensorimotor cortices in aged brains. However, the alpha power increase in both groups implies neuroplastic changes that strengthen the network of alpha power generation over time in young as well as elderly brains. PMID:26528179

  3. Memory load effect in auditory-verbal short-term memory task: EEG fractal and spectral analysis.

    PubMed

    Stokić, Miodrag; Milovanović, Dragan; Ljubisavljević, Miloš R; Nenadović, Vanja; Čukić, Milena

    2015-10-01

    The objective of this preliminary study was to quantify changes in complexity of EEG using fractal dimension (FD) alongside linear methods of spectral power, event-related spectral perturbations, coherence, and source localization of EEG generators for theta (4-7 Hz), alpha (8-12 Hz), and beta (13-23 Hz) frequency bands due to a memory load effect in an auditory-verbal short-term memory (AVSTM) task for words. We examined 20 healthy individuals using the Sternberg's paradigm with increasing memory load (three, five, and seven words). The stimuli were four-letter words. Artifact-free 5-s EEG segments during retention period were analyzed. The most significant finding was the increase in FD with the increase in memory load in temporal regions T3 and T4, and in parietal region Pz, while decrease in FD with increase in memory load was registered in frontal midline region Fz. Results point to increase in frontal midline (Fz) theta spectral power, decrease in alpha spectral power in parietal region-Pz, and increase in beta spectral power in T3 and T4 region with increase in memory load. Decrease in theta coherence within right hemisphere due to memory load was obtained. Alpha coherence increased in posterior regions with anterior decrease. Beta coherence increased in fronto-temporal regions. Source localization delineated theta activity increase in frontal midline region, alpha decrease in superior parietal region, and beta increase in superior temporal gyrus with increase in memory load. In conclusion, FD as a nonlinear measure may serve as a sensitive index for quantifying dynamical changes in EEG signals during AVSTM tasks. PMID:26169106

  4. Modular, bluetooth enabled, wireless electroencephalograph (EEG) platform.

    PubMed

    Lovelace, Joseph A; Witt, Tyler S; Beyette, Fred R

    2013-01-01

    A design for a modular, compact, and accurate wireless electroencephalograph (EEG) system is proposed. EEG is the only non-invasive measure for neuronal function of the brain. Using a number of digital signal processing (DSP) techniques, this neuronal function can be acquired and processed into meaningful representations of brain activity. The system described here utilizes Bluetooth to wirelessly transmit the digitized brain signal for an end application use. In this way, the system is portable, and modular in terms of the device to which it can interface. Brain Computer Interface (BCI) has become a popular extension of EEG systems in modern research. This design serves as a platform for applications using BCI capability. PMID:24111196

  5. A wireless multichannel EEG recording platform.

    PubMed

    Filipe, S; Charvet, G; Foerster, M; Porcherot, J; Bêche, J F; Bonnet, S; Audebert, P; Régis, G; Zongo, B; Robinet, S; Condemine, C; Mestais, C; Guillemaud, R

    2011-01-01

    A wireless multichannel data acquisition system is being designed for ElectroEncephaloGraphy (EEG) recording. The system is based on a custom integrated circuit (ASIC) for signal conditioning, amplification and digitization and also on commercial components for RF transmission. It supports the RF transmission of a 32-channel EEG recording sampled at 1 kHz with a 12-bit resolution. The RF communication uses the MICS band (Medical Implant Communication Service) at 402-405 Mhz. This integration is a first step towards a lightweight EEG cap for Brain Computer Interface (BCI) studies. Here, we present the platform architecture and its submodules. In vivo validations are presented with noise characterization and wireless data transfer measurements. PMID:22255783

  6. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882.1855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry...

  7. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882.1855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry...

  8. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882.1855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry...

  9. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882.1855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry...

  10. Developmental Quantitative EEG Differences during Psychomotor Response to Music.

    ERIC Educational Resources Information Center

    Flohr, John W.; Miller, Daniel C.

    This study examined the electrophysiological differences between baseline EEG frequencies and EEG frequencies obtained during a psychomotor response to musical stimuli. Subjects were 9 children, with mean age of 5.2 years old. Electrophysiological differences between two different musical conditions were also compared. EEG was recorded during 3…

  11. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of transmitters, receivers, and other components used for remotely monitoring or measuring...

  12. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  13. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  14. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  15. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  16. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  17. Interrater agreement for Critical Care EEG Terminology

    PubMed Central

    Gaspard, Nicolas; Hirsch, Lawrence J.; LaRoche, Suzette M.; Hahn, Cecil D.; Westover, M. Brandon

    2016-01-01

    Summary Objective The interpretation of critical care electroencephalography (EEG) studies is challenging because of the presence of many periodic and rhythmic patterns of uncertain clinical significance. Defining the clinical significance of these patterns requires standardized terminology with high interrater agreement (IRA). We sought to evaluate IRA for the final, published American Clinical Neurophysiology Society (ACNS)–approved version of the critical care EEG terminology (2012 version). Our evaluation included terms not assessed previously and incorporated raters with a broad range of EEG reading experience. Methods After reviewing a set of training slides, 49 readers independently completed a Web-based test consisting of 11 identical questions for each of 37 EEG samples (407 questions). Questions assessed whether a pattern was an electrographic seizure; pattern location (main term 1), pattern type (main term 2); and presence and classification of eight other key features (“plus” modifiers, sharpness, absolute and relative amplitude, frequency, number of phases, fluctuation/evolution, and the presence of “triphasic” morphology). Results IRA statistics (κ values) were almost perfect (90–100%) for seizures, main terms 1 and 2, the +S modifier (superimposed spikes/sharp waves or sharply contoured rhythmic delta activity), sharpness, absolute amplitude, frequency, and number of phases. Agreement was substantial for the +F (superimposed fast activity) and +R (superimposed rhythmic delta activity) modifiers (66% and 67%, respectively), moderate for triphasic morphology (58%), and fair for evolution (21%). Significance IRA for most terms in the ACNS critical care EEG terminology is high. These terms are suitable for multicenter research on the clinical significance of critical care EEG patterns. PMID:24888711

  18. Which EEG patterns in coma are nonconvulsive status epilepticus?

    PubMed

    Trinka, Eugen; Leitinger, Markus

    2015-08-01

    Nonconvulsive status epilepticus (NCSE) is common in patients with coma with a prevalence between 5% and 48%. Patients in deep coma may exhibit epileptiform EEG patterns, such as generalized periodic spikes, and there is an ongoing debate about the relationship of these patterns and NCSE. The purposes of this review are (i) to discuss the various EEG patterns found in coma, its fluctuations, and transitions and (ii) to propose modified criteria for NCSE in coma. Classical coma patterns such as diffuse polymorphic delta activity, spindle coma, alpha/theta coma, low output voltage, or burst suppression do not reflect NCSE. Any ictal patterns with a typical spatiotemporal evolution or epileptiform discharges faster than 2.5 Hz in a comatose patient reflect nonconvulsive seizures or NCSE and should be treated. Generalized periodic diacharges or lateralized periodic discharges (GPDs/LPDs) with a frequency of less than 2.5 Hz or rhythmic discharges (RDs) faster than 0.5 Hz are the borderland of NCSE in coma. In these cases, at least one of the additional criteria is needed to diagnose NCSE (a) subtle clinical ictal phenomena, (b) typical spatiotemporal evolution, or (c) response to antiepileptic drug treatment. There is currently no consensus about how long these patterns must be present to qualify for NCSE, and the distinction from nonconvulsive seizures in patients with critical illness or in comatose patients seems arbitrary. The Salzburg Consensus Criteria for NCSE [1] have been modified according to the Standardized Terminology of the American Clinical Neurophysiology Society [2] and validated in three different cohorts, with a sensitivity of 97.2%, a specificity of 95.9%, and a diagnostic accuracy of 96.3% in patients with clinical signs of NCSE. Their diagnostic utility in different cohorts with patients in deep coma has to be studied in the future. This article is part of a Special Issue entitled "Status Epilepticus". PMID:26148985

  19. Automatic sleep onset detection using single EEG sensor.

    PubMed

    Zhuo Zhang; Cuntai Guan; Ti Eu Chan; Juanhong Yu; Ng, Andrew Keong; Haihong Zhang; Chee Keong Kwoh

    2014-01-01

    Sleep has been shown to be imperative for the health and well-being of an individual. To design intelligent sleep management tools, such as the music-induce sleep-aid device, automatic detection of sleep onset is critical. In this work, we propose a simple yet accurate method for sleep onset prediction, which merely relies on Electroencephalogram (EEG) signal acquired from a single frontal electrode in a wireless headband. The proposed method first extracts energy power ratio of theta (4-8Hz) and alpha (8-12Hz) bands along a 3-second shifting window, then calculates the slow wave of each frequency band along the time domain. The resulting slow waves are then fed to a rule-based engine for sleep onset detection. To evaluate the effectiveness of the approach, polysomnographic (PSG) and headband EEG signals were obtained from 20 healthy adults, each of which underwent 2 sessions of sleep events. In total, data from 40 sleep events were collected. Each recording was then analyzed offline by a PSG technologist via visual observation of PSG waveforms, who annotated sleep stages N1 and N2 by using the American Academy of Sleep Medicine (AASM) scoring rules. Using this as the gold standard, our approach achieved a 87.5% accuracy for sleep onset detection. The result is better or at least comparable to the other state of the art methods which use either multi-or single- channel based data. The approach has laid down the foundations for our future work on developing intelligent sleep aid devices. PMID:25570439

  20. Intracranial EEG potentials estimated from MEG sources: A new approach to correlate MEG and iEEG data in epilepsy.

    PubMed

    Grova, Christophe; Aiguabella, Maria; Zelmann, Rina; Lina, Jean-Marc; Hall, Jeffery A; Kobayashi, Eliane

    2016-05-01

    Detection of epileptic spikes in MagnetoEncephaloGraphy (MEG) requires synchronized neuronal activity over a minimum of 4cm2. We previously validated the Maximum Entropy on the Mean (MEM) as a source localization able to recover the spatial extent of the epileptic spike generators. The purpose of this study was to evaluate quantitatively, using intracranial EEG (iEEG), the spatial extent recovered from MEG sources by estimating iEEG potentials generated by these MEG sources. We evaluated five patients with focal epilepsy who had a pre-operative MEG acquisition and iEEG with MRI-compatible electrodes. Individual MEG epileptic spikes were localized along the cortical surface segmented from a pre-operative MRI, which was co-registered with the MRI obtained with iEEG electrodes in place for identification of iEEG contacts. An iEEG forward model estimated the influence of every dipolar source of the cortical surface on each iEEG contact. This iEEG forward model was applied to MEG sources to estimate iEEG potentials that would have been generated by these sources. MEG-estimated iEEG potentials were compared with measured iEEG potentials using four source localization methods: two variants of MEM and two standard methods equivalent to minimum norm and LORETA estimates. Our results demonstrated an excellent MEG/iEEG correspondence in the presumed focus for four out of five patients. In one patient, the deep generator identified in iEEG could not be localized in MEG. MEG-estimated iEEG potentials is a promising method to evaluate which MEG sources could be retrieved and validated with iEEG data, providing accurate results especially when applied to MEM localizations. Hum Brain Mapp 37:1661-1683, 2016. © 2016 Wiley Periodicals, Inc. PMID:26931511

  1. Analysis of EEG activity in response to binaural beats with different frequencies.

    PubMed

    Gao, Xiang; Cao, Hongbao; Ming, Dong; Qi, Hongzhi; Wang, Xuemin; Wang, Xiaolu; Chen, Runge; Zhou, Peng

    2014-12-01

    When two coherent sounds with nearly similar frequencies are presented to each ear respectively with stereo headphones, the brain integrates the two signals and produces a sensation of a third sound called binaural beat (BB). Although earlier studies showed that BB could influence behavior and cognition, common agreement on the mechanism of BB has not been reached yet. In this work, we employed Relative Power (RP), Phase Locking Value (PLV) and Cross-Mutual Information (CMI) to track EEG changes during BB stimulations. EEG signals were acquired from 13 healthy subjects. Five-minute BBs with four different frequencies were tested: delta band (1 Hz), theta band (5 Hz), alpha band (10 Hz) and beta band (20 Hz). We observed RP increase in theta and alpha bands and decrease in beta band during delta and alpha BB stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified. Connectivity changes were detected following the variation of RP during BB stimulations. Our observation supports the hypothesis that BBs could affect functional brain connectivity, suggesting that the mechanism of BB-brain interaction is worth further study. PMID:25448376

  2. Simultaneous EEG-fMRI brain signatures of auditory cue utilization

    PubMed Central

    Scharinger, Mathias; Herrmann, Björn; Nierhaus, Till; Obleser, Jonas

    2014-01-01

    Optimal utilization of acoustic cues during auditory categorization is a vital skill, particularly when informative cues become occluded or degraded. Consequently, the acoustic environment requires flexible choosing and switching amongst available cues. The present study targets the brain functions underlying such changes in cue utilization. Participants performed a categorization task with immediate feedback on acoustic stimuli from two categories that varied in duration and spectral properties, while we simultaneously recorded Blood Oxygenation Level Dependent (BOLD) responses in fMRI and electroencephalograms (EEGs). In the first half of the experiment, categories could be best discriminated by spectral properties. Halfway through the experiment, spectral degradation rendered the stimulus duration the more informative cue. Behaviorally, degradation decreased the likelihood of utilizing spectral cues. Spectrally degrading the acoustic signal led to increased alpha power compared to nondegraded stimuli. The EEG-informed fMRI analyses revealed that alpha power correlated with BOLD changes in inferior parietal cortex and right posterior superior temporal gyrus (including planum temporale). In both areas, spectral degradation led to a weaker coupling of BOLD response to behavioral utilization of the spectral cue. These data provide converging evidence from behavioral modeling, electrophysiology, and hemodynamics that (a) increased alpha power mediates the inhibition of uninformative (here spectral) stimulus features, and that (b) the parietal attention network supports optimal cue utilization in auditory categorization. The results highlight the complex cortical processing of auditory categorization under realistic listening challenges. PMID:24926232

  3. Mecamylamine reduces some EEG effects of nicotine chewing gum in humans.

    PubMed

    Pickworth, W B; Herning, R I; Henningfield, J E

    1988-05-01

    Spontaneous EEG was recorded in nine cigarette smokers who had been abstinent from tobacco for 12 hr. Subjects were treated with a capsule containing either centrally acting nicotine blocker, mecamylamine (10 mg), or placebo. At each of three 60-min intervals after the capsule was ingested, the subjects chewed two pieces of gum containing a total of 0, 4 or 8 mg of nicotine. Nicotine and mecamylamine dose combinations were randomized across subjects. Two three-minute periods of spontaneous EEG were recorded before the capsule and before and after gum chewing from bipolar electrode montages at the following positions: Cz-T5, Cz-T6, Cz-F7 and Cz-F8. During one period the subjects relaxed with eyes closed, in the other period they performed a math task with eyes open. When the drugs were given individually, mecamylamine decreased beta power and nicotine gum (4 and 8 mg) increased alpha frequency. Mecamylamine pretreatment prevented the increase in alpha frequency caused by the 4 mg gum dose but not the 8 mg dose. Alpha power was increased by the 8 mg gum dose and that increase was prevented by mecamylamine. Self-reported ratings of the "strength" of the gum were significantly diminished by mecamylamine pretreatment. The data are consistent with the results of earlier studies which indicate that the effects of tobacco administration and withdrawal are mediated by central actions of nicotine. PMID:3174738

  4. Spectral and brain mapping analysis of EEG based on Pwelch in schizophrenic patients

    NASA Astrophysics Data System (ADS)

    Akbar, Y.; Khotimah, S. N.; Haryanto, F.

    2016-03-01

    The aim of this study is to investigate and analyze the differences of power spectral distribution in various frequency bands between healthy subjects and schizophrenic patients. Subjects in this study were 8 people consisting of 4 schizophrenic patients and 4 healthy subjects. Subjects were recorded from 12 electrodes with Electroencephalography (EEG). EEG signals were recorded during a resting eye-closed state for 4-6 minutes. Data were extracted and analyzed by centering and filtering, then performed using Welch Periodogram technique for the spectral estimation with a Hamming window. The results of this study showed that delta power spectral in schizophrenic patients increased ten times from healthy subjects; theta power spectral in schizophrenic patients increased three times from healthy subjects; alpha power spectral in schizophrenic patients decreased with an increase of one third of healthy subjects. These results were confirmed by Kolmogorov-Smirnov test showing there were significant differences between schizophrenic and healthy subjects on delta, theta and alpha brain wave. Based on the results of Brain Mapping analysis showed that there was significant increasing in the activity of delta waves and theta waves in frontal lobe of schizophrenics, whereas the alpha waves indicated a decrease in the occipital lobe in all schizophrenic patients.

  5. Complex network analysis of resting state EEG in amnestic mild cognitive impairment patients with type 2 diabetes

    PubMed Central

    Zeng, Ke; Wang, Yinghua; Ouyang, Gaoxiang; Bian, Zhijie; Wang, Lei; Li, Xiaoli

    2015-01-01

    Purpose: Diabetes is a great risk factor for dementia and mild cognitive impairment (MCI). This study investigates whether complex network-derived features in resting state EEG (rsEEG) could be applied as a biomarker to distinguish amnestic mild cognitive impairment (aMCI) from normal cognitive function in subjects with type 2 diabetes (T2D). Method: In this study, EEG was recorded in 28 patients with T2D (16 aMCI patients and 12 controls) during a no-task eyes-closed resting state. Pair-wise synchronization of rsEEG signals were assessed in six frequency bands (delta, theta, lower alpha, upper alpha, beta, and gamma) using phase lag index (PLI) and grouped into long distance (intra- and inter-hemispheric) and short distance interactions. PLI-weighted connectivity networks were also constructed, and characterized by mean clustering coefficient and path length. The correlation of these features and Montreal Cognitive Assessment (MoCA) scores was assessed. Results: Main findings of this study were as follows: (1) In comparison with controls, patients with aMCI had a significant decrease of global mean PLI in lower alpha, upper alpha, and beta bands. Lower functional connection at short and long intra-hemispheric distance mainly appeared on the left hemisphere. (2) In the lower alpha band, clustering coefficient was significantly lower in aMCI group, and the path length significantly increased. (3) Cognitive status measured by MoCA had a significant positive correlation with cluster coefficient and negative correlation with path length in lower alpha band. Conclusions: The brain network of aMCI patients displayed a disconnection syndrome and a loss of small-world architecture. The correlation between cognitive states and network characteristics suggested that the more in deterioration of the diabetes patients' cognitive state, the less optimal the network organization become. Hence, the complex network-derived biomarkers based on EEG could be employed to track

  6. Fractal Dimension in Epileptic EEG Signal Analysis

    NASA Astrophysics Data System (ADS)

    Uthayakumar, R.

    Fractal Analysis is the well developed theory in the data analysis of non-linear time series. Especially Fractal Dimension is a powerful mathematical tool for modeling many physical and biological time signals with high complexity and irregularity. Fractal dimension is a suitable tool for analyzing the nonlinear behaviour and state of the many chaotic systems. Particularly in analysis of chaotic time series such as electroencephalograms (EEG), this feature has been used to identify and distinguish specific states of physiological function.Epilepsy is the main fatal neurological disorder in our brain, which is analyzed by the biomedical signal called Electroencephalogram (EEG). The detection of Epileptic seizures in the EEG Signals is an important tool in the diagnosis of epilepsy. So we made an attempt to analyze the EEG in depth for knowing the mystery of human consciousness. EEG has more fluctuations recorded from the human brain due to the spontaneous electrical activity. Hence EEG Signals are represented as Fractal Time Series.The algorithms of fractal dimension methods have weak ability to the estimation of complexity in the irregular graphs. Divider method is widely used to obtain the fractal dimension of curves embedded into a 2-dimensional space. The major problem is choosing initial and final step length of dividers. We propose a new algorithm based on the size measure relationship (SMR) method, quantifying the dimensional behaviour of irregular rectifiable graphs with minimum time complexity. The evidence for the suitability (equality with the nature of dimension) of the algorithm is illustrated graphically.We would like to demonstrate the criterion for the selection of dividers (minimum and maximum value) in the calculation of fractal dimension of the irregular curves with minimum time complexity. For that we design a new method of computing fractal dimension (FD) of biomedical waveforms. Compared to Higuchi's algorithm, advantages of this method include

  7. The processing and transmission of EEG data

    NASA Technical Reports Server (NTRS)

    Schulze, A. E.

    1974-01-01

    Interest in sleep research was stimulated by the discovery of a number of physiological changes that occur during sleep and by the observed effects of sleep on physical and mental performance and status. The use of the relatively new methods of EEG measurement, transmission, and automatic scoring makes sleep analysis and categorization feasible. Sleep research involving the use of the EEG as a fundamental input has the potential of answering many unanswered questions involving physical and mental behavior, drug effects, circadian rhythm, and anesthesia.

  8. Functional coupling of sensorimotor and associative areas during a catching ball task: a qEEG coherence study

    PubMed Central

    2012-01-01

    Background Catching an object is a complex movement that involves not only programming but also effective motor coordination. Such behavior is related to the activation and recruitment of cortical regions that participates in the sensorimotor integration process. This study aimed to elucidate the cortical mechanisms involved in anticipatory actions when performing a task of catching an object in free fall. Methods Quantitative electroencephalography (qEEG) was recorded using a 20-channel EEG system in 20 healthy right-handed participants performed the catching ball task. We used the EEG coherence analysis to investigate subdivisions of alpha (8-12 Hz) and beta (12-30 Hz) bands, which are related to cognitive processing and sensory-motor integration. Results Notwithstanding, we found the main effects for the factor block; for alpha-1, coherence decreased from the first to sixth block, and the opposite effect occurred for alpha-2 and beta-2, with coherence increasing along the blocks. Conclusion It was concluded that to perform successfully our task, which involved anticipatory processes (i.e. feedback mechanisms), subjects exhibited a great involvement of sensory-motor and associative areas, possibly due to organization of information to process visuospatial parameters and further catch the falling object. PMID:22364485

  9. Attention-related EEG markers in adult ADHD.

    PubMed

    Hasler, Roland; Perroud, Nader; Meziane, Hadj Boumediene; Herrmann, François; Prada, Paco; Giannakopoulos, Panteleimon; Deiber, Marie-Pierre

    2016-07-01

    ADHD status affects both bottom-up sensory processing and top-down attentional selection, impairing professional and social functioning. The objective of the study was to investigate the functional mechanisms of attention deficits in adult ADHD by examining the electrophysiological activities associated with bottom-up attentional cueing (temporal and spatial orienting of attention) and top-down control (conflict resolution). Continuous EEG was recorded in 21 adult ADHD patients (40.05±9.5 years) and 20 healthy adults (25.5±4 years) during performance of the Attention Network Test (ANT). We examined the cue and target-related P1, N1 and P3 components as well as the contingent negative variation (CNV) developing between cue and target. Oscillatory responses were analyzed in the alpha (8-13Hz) and beta (14-19Hz) frequency bands. ADHD patients performed similarly to controls but showed reduced P3 amplitude, larger early CNV decrementing over time, reduced preparatory activation in both alpha and beta bands, as well as flattened target-related posterior alpha and beta responses. As compared to controls, the inverted CNV pattern suggested peculiar preparatory processing in ADHD patients. The singular pattern of target-related beta response indicated increased inhibitory processes in the case of easier task resolution and more generally, the lack of association between conflict resolution speed and beta activity supported alternative executive processing in ADHD patients. Overall, the reduced activation of the functional networks devoted to bottom-up and top-down attention suggests that adult ADHD patients engage reduced cortical resources in this composite task, compatible with the cortical hypoarousal model. PMID:27178310

  10. Zazen meditation and no-task resting EEG compared with LORETA intracortical source localization.

    PubMed

    Faber, Pascal L; Lehmann, Dietrich; Gianotti, Lorena R R; Milz, Patricia; Pascual-Marqui, Roberto D; Held, Marlene; Kochi, Kieko

    2015-02-01

    Meditation is a self-induced and willfully initiated practice that alters the state of consciousness. The meditation practice of Zazen, like many other meditation practices, aims at disregarding intrusive thoughts while controlling body posture. It is an open monitoring meditation characterized by detached moment-to-moment awareness and reduced conceptual thinking and self-reference. Which brain areas differ in electric activity during Zazen compared to task-free resting? Since scalp electroencephalography (EEG) waveforms are reference-dependent, conclusions about the localization of active brain areas are ambiguous. Computing intracerebral source models from the scalp EEG data solves this problem. In the present study, we applied source modeling using low resolution brain electromagnetic tomography (LORETA) to 58-channel scalp EEG data recorded from 15 experienced Zen meditators during Zazen and no-task resting. Zazen compared to no-task resting showed increased alpha-1 and alpha-2 frequency activity in an exclusively right-lateralized cluster extending from prefrontal areas including the insula to parts of the somatosensory and motor cortices and temporal areas. Zazen also showed decreased alpha and beta-2 activity in the left angular gyrus and decreased beta-1 and beta-2 activity in a large bilateral posterior cluster comprising the visual cortex, the posterior cingulate cortex and the parietal cortex. The results include parts of the default mode network and suggest enhanced automatic memory and emotion processing, reduced conceptual thinking and self-reference on a less judgmental, i.e., more detached moment-to-moment basis during Zazen compared to no-task resting. PMID:25284209

  11. A systematic review of the neurophysiology of mindfulness on EEG oscillations.

    PubMed

    Lomas, Tim; Ivtzan, Itai; Fu, Cynthia H Y

    2015-10-01

    Mindfulness meditation has been purported to be a beneficial practice for wellbeing. It would therefore be expected that the neurophysiology of mindfulness would reflect this impact on wellbeing. However, investigations of the effects of mindfulness have generated mixed reports of increases, decreases, as well as no differences in EEG oscillations in comparison with a resting state and a variety of tasks. We have performed a systematic review of EEG studies of mindfulness meditation in order to determine any common effects and to identify factors which may impact on the effects. Databases were reviewed from 1966 to August 2015. Eligibility criteria included empirical quantitative analyses of mindfulness meditation practice and EEG measurements acquired in relation to practice. A total of 56 papers met the eligibility criteria and were included in the systematic review, consisting of a total 1715 subjects: 1358 healthy individuals and 357 individuals with psychiatric diagnoses. Studies were principally examined for power outcomes in each bandwidth, in particular the power differentials between mindfulness and a control state, as well as outcomes relating to hemispheric asymmetry and event-related potentials. The systematic review revealed that mindfulness was most commonly associated with enhanced alpha and theta power as compared to an eyes closed resting state, although such outcomes were not uniformly reported. No consistent patterns were observed with respect to beta, delta and gamma bandwidths. In summary, mindfulness is associated with increased alpha and theta power in both healthy individuals and in patient groups. This co-presence of elevated alpha and theta may signify a state of relaxed alertness which is conducive to mental health. PMID:26441373

  12. Use of electroencephalography (EEG) to assess CNS changes produced by pesticides with different modes of action: effects of permethrin, deltamethrin, fipronil, imidacloprid, carbaryl, and triadimefon.

    PubMed

    Freeborn, Danielle L; McDaniel, Katherine L; Moser, Virginia C; Herr, David W

    2015-01-15

    The electroencephalogram (EEG) is an apical measure, capable of detecting changes in brain neuronal activity produced by internal or external stimuli. We assessed whether pesticides with different modes of action produced different changes in the EEG of adult male Long-Evans rats. The EEG was recorded using two montages (visual cortex referenced to the cerebellum and to the frontal cortex) in unrestrained rats at the time of peak behavioral effects. Pesticides included: permethrin and deltamethrin (Type I and Type II pyrethroids; 2 h), fipronil (single and repeated doses; phenylpyrazole; 6 h), imidacloprid (neonicotinoid; 2 h), carbaryl (carbamate; 0.5 h), and triadimefon (triazole; 1 h), using dosages that produced approximately an ED30 or an ED50-ED80 change in motor activity. Permethrin (43, 100 mg/kg) increased amplitudes or areas (delta, alpha, or gamma bands) in the EEG. Deltamethrin (2.5, 5.5 mg/kg) reduced the amplitudes or areas of the delta, theta, alpha, beta, and gamma bands, but the changes were not dose-related. A single treatment with fipronil (25, 50 mg/kg, but not 5, 10 mg/kg) decreased gamma band area. Additional changes in the delta, theta, and gamma bands were observed when fipronil (5, 10 mg/kg) was administered for 14 days. Imidacloprid (50, 100 mg/kg) did not alter the EEG. Carbaryl (10, 50 mg/kg) decreased theta area, and decreased delta and increased beta frequency. Triadimefon (75, 150 mg/kg) produced minimal changes in the EEG. The results show that the EEG is affected differently by approximately equipotent doses of pesticides with different modes of action. PMID:25481984

  13. 'Time-scribe': a universal time writer for any EEG/polygraph chart recorder.

    PubMed

    Ives, J

    1984-04-01

    An ubiquitous digital clock 'time-scribe' with a unique pen-galvanometer writer section has been described which should greatly improve the correlation of a long term EEG with any other time related event or medium. The output of the clock generates on any pen-galvanometer based chart recorder numerical and some alpha characters which are easily and immediately readable. Because of its convenience, simplicity and basic practical application it should also stimulate discussion for the unification of time write-out standards and methods. PMID:6200303

  14. Target Speaker Detection with Concealed EEG Around the Ear

    PubMed Central

    Mirkovic, Bojana; Bleichner, Martin G.; De Vos, Maarten; Debener, Stefan

    2016-01-01

    Target speaker identification is essential for speech enhancement algorithms in assistive devices aimed toward helping the hearing impaired. Several recent studies have reported that target speaker identification is possible through electroencephalography (EEG) recordings. If the EEG system could be reduced to acceptable size while retaining the signal quality, hearing aids could benefit from the integration with concealed EEG. To compare the performance of a multichannel around-the-ear EEG system with high-density cap EEG recordings an envelope tracking algorithm was applied in a competitive speaker paradigm. The data from 20 normal hearing listeners were concurrently collected from the traditional state-of-the-art laboratory wired EEG system and a wireless mobile EEG system with two bilaterally-placed around-the-ear electrode arrays (cEEGrids). The results show that the cEEGrid ear-EEG technology captured neural signals that allowed the identification of the attended speaker above chance-level, with 69.3% accuracy, while cap-EEG signals resulted in the accuracy of 84.8%. Further analyses investigated the influence of ear-EEG signal quality and revealed that the envelope tracking procedure was unaffected by variability in channel impedances. We conclude that the quality of concealed ear-EEG recordings as acquired with the cEEGrid array has potential to be used in the brain-computer interface steering of hearing aids. PMID:27512364

  15. Target Speaker Detection with Concealed EEG Around the Ear.

    PubMed

    Mirkovic, Bojana; Bleichner, Martin G; De Vos, Maarten; Debener, Stefan

    2016-01-01

    Target speaker identification is essential for speech enhancement algorithms in assistive devices aimed toward helping the hearing impaired. Several recent studies have reported that target speaker identification is possible through electroencephalography (EEG) recordings. If the EEG system could be reduced to acceptable size while retaining the signal quality, hearing aids could benefit from the integration with concealed EEG. To compare the performance of a multichannel around-the-ear EEG system with high-density cap EEG recordings an envelope tracking algorithm was applied in a competitive speaker paradigm. The data from 20 normal hearing listeners were concurrently collected from the traditional state-of-the-art laboratory wired EEG system and a wireless mobile EEG system with two bilaterally-placed around-the-ear electrode arrays (cEEGrids). The results show that the cEEGrid ear-EEG technology captured neural signals that allowed the identification of the attended speaker above chance-level, with 69.3% accuracy, while cap-EEG signals resulted in the accuracy of 84.8%. Further analyses investigated the influence of ear-EEG signal quality and revealed that the envelope tracking procedure was unaffected by variability in channel impedances. We conclude that the quality of concealed ear-EEG recordings as acquired with the cEEGrid array has potential to be used in the brain-computer interface steering of hearing aids. PMID:27512364

  16. Use of electroencephalography (EEG) to assess CNS changes produced by pesticides with different modes of action: Effects of permethrin, deltamethrin, fipronil, imidacloprid, carbaryl, and triadimefon

    SciTech Connect

    Freeborn, Danielle L. McDaniel, Katherine L. Moser, Virginia C. Herr, David W.

    2015-01-15

    The electroencephalogram (EEG) is an apical measure, capable of detecting changes in brain neuronal activity produced by internal or external stimuli. We assessed whether pesticides with different modes of action produced different changes in the EEG of adult male Long–Evans rats. The EEG was recorded using two montages (visual cortex referenced to the cerebellum and to the frontal cortex) in unrestrained rats at the time of peak behavioral effects. Pesticides included: permethrin and deltamethrin (Type I and Type II pyrethroids; 2 h), fipronil (single and repeated doses; phenylpyrazole; 6 h), imidacloprid (neonicotinoid; 2 h), carbaryl (carbamate; 0.5 h), and triadimefon (triazole; 1 h), using dosages that produced approximately an ED{sub 30} or an ED{sub 50}–ED{sub 80} change in motor activity. Permethrin (43, 100 mg/kg) increased amplitudes or areas (delta, alpha, or gamma bands) in the EEG. Deltamethrin (2.5, 5.5 mg/kg) reduced the amplitudes or areas of the delta, theta, alpha, beta, and gamma bands, but the changes were not dose-related. A single treatment with fipronil (25, 50 mg/kg, but not 5, 10 mg/kg) decreased gamma band area. Additional changes in the delta, theta, and gamma bands were observed when fipronil (5, 10 mg/kg) was administered for 14 days. Imidacloprid (50, 100 mg/kg) did not alter the EEG. Carbaryl (10, 50 mg/kg) decreased theta area, and decreased delta and increased beta frequency. Triadimefon (75, 150 mg/kg) produced minimal changes in the EEG. The results show that the EEG is affected differently by approximately equipotent doses of pesticides with different modes of action. - Highlights: • Pesticides with different modes of action have different effects on in vivo rodent EEG. • The EEG was also changed differently after single vs. repeated treatment with fipronil. • The data suggest that EEG may be used as an apical measure for detecting chemical effects on the central nervous system.

  17. Separation and reconstruction of BCG and EEG signals during continuous EEG and fMRI recordings

    PubMed Central

    Xia, Hongjing; Ruan, Dan; Cohen, Mark S.

    2014-01-01

    Despite considerable effort to remove it, the ballistocardiogram (BCG) remains a major artifact in electroencephalographic data (EEG) acquired inside magnetic resonance imaging (MRI) scanners, particularly in continuous (as opposed to event-related) recordings. In this study, we have developed a new Direct Recording Prior Encoding (DRPE) method to extract and separate the BCG and EEG components from contaminated signals, and have demonstrated its performance by comparing it quantitatively to the popular Optimal Basis Set (OBS) method. Our modified recording configuration allows us to obtain representative bases of the BCG- and EEG-only signals. Further, we have developed an optimization-based reconstruction approach to maximally incorporate prior knowledge of the BCG/EEG subspaces, and of the signal characteristics within them. Both OBS and DRPE methods were tested with experimental data, and compared quantitatively using cross-validation. In the challenging continuous EEG studies, DRPE outperforms the OBS method by nearly sevenfold in separating the continuous BCG and EEG signals. PMID:25002836

  18. Role of Frontal Alpha Oscillations in Creativity

    PubMed Central

    Lustenberger, Caroline; Boyle, Michael R.; Foulser, A. Alban; Mellin, Juliann M.; Fröhlich, Flavio

    2015-01-01

    Creativity, the ability to produce innovative ideas, is a key higher-order cognitive function that is poorly understood. At the level of macroscopic cortical network dynamics, recent EEG data suggests that cortical oscillations in the alpha frequency band (8 – 12 Hz) are correlated with creative thinking. However, whether alpha oscillations play a fundamental role in creativity has remained unknown. Here we show that creativity is increased by enhancing alpha power using 10 Hz transcranial alternating current stimulation (10Hz-tACS) of the frontal cortex. In a study of 20 healthy participants with a randomized, balanced cross-over design, we found a significant improvement of 7.4% in the Creativity Index measured by the Torrance Test of Creative Thinking, a comprehensive and most frequently used assay of creative potential and strengths. In a second similar study with 20 subjects, 40Hz-tACS was used in instead of 10Hz-tACS to rule out a general “electrical stimulation” effect. No significant change in the Creativity Index was found for such frontal gamma stimulation. Our results suggest that alpha activity in frontal brain areas is selectively involved in creativity; this enhancement represents the first demonstration of specific neuronal dynamics that drive creativity and can be modulated by non-invasive brain stimulation. Our findings agree with the model that alpha recruitment increases with internal processing demands and is involved in inhibitory top-down control, which is an important requirement for creative ideation. PMID:25913062

  19. Inferring Seizure Frequency From Brief EEG Recordings

    PubMed Central

    Westover, M. Brandon; Bianchi, Matt T.; Shafi, Mouhsin; Hoch, Daniel B.; Cole, Andrew J.; Chiappa, Keith; Cash, Sydney S.

    2012-01-01

    Routine EEGs remain a cornerstone test in caring for people with epilepsy. Although rare, a self-limited seizure (clinical or electrographic only) may be observed during such brief EEGs. The implications of observing a seizure in this situation, especially with respect to inferring the underlying seizure frequency, are unclear. The issue is complicated by the inaccuracy of patient-reported estimations of seizure frequency. The treating clinician is often left to wonder whether the single seizure indicates very frequent seizures, or if it is of lesser significance. We applied standard concepts of probabilistic inference to a simple model of seizure incidence to provide some guidance for clinicians facing this situation. Our analysis establishes upper and lower bounds on the seizure rate implied by observing a single seizure during routine EEG. Not surprisingly, with additional information regarding the expected seizure rate, these bounds can be further constrained. This framework should aid the clinician in applying a more principled approach toward decision making in the setting of a single seizure on a routine EEG. PMID:23545768

  20. Music Shifts Frontal EEG in Depressed Adolescents.

    ERIC Educational Resources Information Center

    Field, Tiffany; Martinez, Alex; Nawrocki, Thomas; Pickens, Jeffrey; Fox, Nathan A.; Schanberg, Saul

    1998-01-01

    Fourteen chronically depressed female adolescents listened to rock music for a 23-minute session. EEG was recorded and saliva samples were collected to determine the effects of the music on stress hormone cortisol levels. No differences were reported for mood state; however, cortisol levels decreased and relative right-frontal activation was…

  1. Improved EEG Event Classification Using Differential Energy

    PubMed Central

    Harati, A.; Golmohammadi, M.; Lopez, S.; Obeid, I.; Picone, J.

    2016-01-01

    Feature extraction for automatic classification of EEG signals typically relies on time frequency representations of the signal. Techniques such as cepstral-based filter banks or wavelets are popular analysis techniques in many signal processing applications including EEG classification. In this paper, we present a comparison of a variety of approaches to estimating and postprocessing features. To further aid in discrimination of periodic signals from aperiodic signals, we add a differential energy term. We evaluate our approaches on the TUH EEG Corpus, which is the largest publicly available EEG corpus and an exceedingly challenging task due to the clinical nature of the data. We demonstrate that a variant of a standard filter bank-based approach, coupled with first and second derivatives, provides a substantial reduction in the overall error rate. The combination of differential energy and derivatives produces a 24% absolute reduction in the error rate and improves our ability to discriminate between signal events and background noise. This relatively simple approach proves to be comparable to other popular feature extraction approaches such as wavelets, but is much more computationally efficient. PMID:27213180

  2. Changes in EEG power spectra and behavioral states in rats exposed to the acetylcholinesterase inhibitor chlorpyrifos and muscarinic agonist oxotremorine.

    PubMed

    Timofeeva, O A; Gordon, C J

    2001-03-01

    Organophosphates (OPs) inhibit acetylcholinesterase (AChE) activity causing cholinergic stimulation in the central nervous system (CNS). Cholinergic systems are crucial in electroencephalogram (EEG) generation and regulation of behavior; however, little is known about how OP exposure affects the EEG and behavioral states. We recorded EEG, core temperature and motor activity before and after exposure to the OP pesticide chlorpyrifos (CHP) in adult female rats implanted with telemetric transmitters. The recording and reference electrodes were placed in the occipital and frontal bones, respectively. The animals received CHP, 25 mg/kg, p.o., or oxotremorine (OX), 0.2 mg/kg, s.c. CHP led to a significant increase in delta (0.1-3.5 Hz), slow theta (4-6.5 Hz), gamma 2 (35.5-50 Hz), reduction in fast theta (7-8.5 Hz), alpha/sigma (9-14 Hz), beta 1 (14.5-24 Hz), beta 2 (24.5-30 Hz) and gamma 1 (30.5-35 Hz) powers, slowing of peak frequencies in 1-9 Hz range, hypothermia and decrease in motor activity. The drop in 7-14 Hz was associated with cholinergic suppression of sleep spindles. Changes in behavioral state were characterized by dramatic diminution of sleep postures and exploring activity and prolongation of quiet waking. There was recovery in all bands in spite of continued inhibition of AChE activity [44,45] in rats exposed to CHP. OX-induced EEG and behavioral alterations were similar to CHP except there was no increase in delta and the onset and recovery were more rapid. We did not find a correlation between the EEG and core temperature alterations. Overall, changes in EEG (except in delta band) and behavior following CHP were attributable to muscarinic stimulation. Cortical arousal together with increased quiet waking and decreased sleep after CHP occurred independently from inhibition of motor activity and lowering of core temperature. PMID:11223004

  3. Effets des radiofréquences sur le système nerveux central chez lʼhomme : EEG, sommeil, cognition, vascularisation

    NASA Astrophysics Data System (ADS)

    Ghosn, Rania; Villégier, Anne-Sophie; Selmaoui, Brahim; Thuróczy, Georges; de Sèze, René

    2013-05-01

    Most of clinical studies on radiofrequency electromagnetic fields (RF) were directed at mobile phone-related exposures, usually at the level of the head, at their effect on some physiological functions including sleep, brain electrical activity (EEG), cognitive processes, brain vascularisation, and more generally on the cardiovascular and endocrine systems. They were frequently carried out on healthy adults. Effects on the amplitude of EEG alpha waves, mainly during sleep, look reproducible. It would however be important to define more precisely whether and how the absence of electromagnetic disturbance between RF exposure and the recording systems is checked. No consensus arises about cognitive effects. Some effects on cerebral vascularisation need complementary work.

  4. Evidence for susceptibility of intrathymic T-cell precursors and their progeny carrying T-cell antigen receptor phenotypes TCR alpha beta + and TCR gamma delta + to human immunodeficiency virus infection: a mechanism for CD4+ (T4) lymphocyte depletion.

    PubMed Central

    Schnittman, S M; Denning, S M; Greenhouse, J J; Justement, J S; Baseler, M; Kurtzberg, J; Haynes, B F; Fauci, A S

    1990-01-01

    Individuals infected by the human immunodeficiency virus type 1 (HIV-1) demonstrate progressive depletion and qualitative dysfunction of the helper T4 (CD4+) cell population. Mechanisms proposed for attrition of CD4+ T cells include direct cytopathicity of these mature cells following infection as well as infection of early T-lymphocyte progenitors. The latter mechanism could lead to failure to regenerate mature functioning CD4+ T cells. The present study determines the susceptibility of thymocytes at various stages of maturity to infection with HIV-1. Various normal thymocyte populations were inoculated with HIV-1, including unfractionated (UF), CD3- CD4- CD8- ["triple negative" (TN)], CD4+ CD8+ ["double positive" (DP)] thymocytes, and thymocyte populations obtained by limited dilution cloning. Cultures were studied for the presence of HIV-1 DNA by polymerase chain reaction in addition to examination for reverse transcriptase activity. We determined that transformed T-cell and thymocyte cell lines completely lacking CD4 were not susceptible to infection by HIV-1, whereas all of the following lines were: UF thymocytes (70-90% CD4hi+); DP thymocytes (99% CD4hi+); TN thymocytes (0% CD4hi+); and TCR alpha beta +, TCR gamma delta +, or CD16+ CD3- (natural killer) thymocyte clones expressing variable levels of CD4 and representing the progeny of TN thymocytes. [TCR alpha beta + and TCR gamma delta + refer to the chains of the T-cell antigen receptor (TCR), and CD4hi refers to a strong rightward shift (greater than 30 linear channels) of the CD4 curve on flow cytometric analysis compared with control.] Monoclonal antibodies (mAbs) to CD4 (T4a epitope) but not to CD3 (T3) were capable of blocking infection of mature and immature CD4hi+ thymocytes. Moreover, anti-CD4(T4a) mAbs also inhibited infection of CD4hi- TN thymocytes, indicating that these T-cell precursors--despite their apparent "triple negativity" (CD3- CD4hi- CD8-)--expressed sufficient CD4 molecules to become

  5. EEG microstates of wakefulness and NREM sleep.

    PubMed

    Brodbeck, Verena; Kuhn, Alena; von Wegner, Frederic; Morzelewski, Astrid; Tagliazucchi, Enzo; Borisov, Sergey; Michel, Christoph M; Laufs, Helmut

    2012-09-01

    EEG-microstates exploit spatio-temporal EEG features to characterize the spontaneous EEG as a sequence of a finite number of quasi-stable scalp potential field maps. So far, EEG-microstates have been studied mainly in wakeful rest and are thought to correspond to functionally relevant brain-states. Four typical microstate maps have been identified and labeled arbitrarily with the letters A, B, C and D. We addressed the question whether EEG-microstate features are altered in different stages of NREM sleep compared to wakefulness. 32-channel EEG of 32 subjects in relaxed wakefulness and NREM sleep was analyzed using a clustering algorithm, identifying the most dominant amplitude topography maps typical of each vigilance state. Fitting back these maps into the sleep-scored EEG resulted in a temporal sequence of maps for each sleep stage. All 32 subjects reached sleep stage N2, 19 also N3, for at least 1 min and 45 s. As in wakeful rest we found four microstate maps to be optimal in all NREM sleep stages. The wake maps were highly similar to those described in the literature for wakefulness. The sleep stage specific map topographies of N1 and N3 sleep showed a variable but overall relatively high degree of spatial correlation to the wake maps (Mean: N1 92%; N3 87%). The N2 maps were the least similar to wake (mean: 83%). Mean duration, total time covered, global explained variance and transition probabilities per subject, map and sleep stage were very similar in wake and N1. In wake, N1 and N3, microstate map C was most dominant w.r.t. global explained variance and temporal presence (ratio total time), whereas in N2 microstate map B was most prominent. In N3, the mean duration of all microstate maps increased significantly, expressed also as an increase in transition probabilities of all maps to themselves in N3. This duration increase was partly--but not entirely--explained by the occurrence of slow waves in the EEG. The persistence of exactly four main microstate

  6. Folate receptor {alpha} regulates cell proliferation in mouse gonadotroph {alpha}T3-1 cells

    SciTech Connect

    Yao, Congjun; Evans, Chheng-Orn; Stevens, Victoria L.; Owens, Timothy R.; Oyesiku, Nelson M.

    2009-11-01

    We have previously found that the mRNA and protein levels of the folate receptor alpha (FR{alpha}) are uniquely over-expressed in clinically human nonfunctional (NF) pituitary adenomas, but the mechanistic role of FR{alpha} has not fully been determined. We investigated the effect of FR{alpha} over-expression in the mouse gonadotroph {alpha}T3-1 cell line as a model for NF pituitary adenomas. We found that the expression and function of FR{alpha} were strongly up-regulated, by Western blotting and folic acid binding assay. Furthermore, we found a higher cell growth rate, an enhanced percentage of cells in S-phase by BrdU assay, and a higher PCNA staining. These observations indicate that over-expression of FR{alpha} promotes cell proliferation. These effects were abrogated in the same {alpha}T3-1 cells when transfected with a mutant FR{alpha} cDNA that confers a dominant-negative phenotype by inhibiting folic acid binding. Finally, by real-time quantitative PCR, we found that mRNA expression of NOTCH3 was up-regulated in FR{alpha} over-expressing cells. In summary, our data suggests that FR{alpha} regulates pituitary tumor cell proliferation and mechanistically may involve the NOTCH pathway. Potentially, this finding could be exploited to develop new, innovative molecular targeted treatment for human NF pituitary adenomas.

  7. Exercise and DHA prevent the negative effects of hypoxia on EEG and nerve conduction velocity.

    PubMed

    Erken, Haydar Ali; Erken, Gülten; Colak, Rıdvan; Genç, Osman

    2013-12-01

    It is known that hypoxia has a negative effect on nervous system functions, but exercise and DHA (docosahexaenoic acid) have positive effect. In this study, it was investigated whether exercise and/or DHA can prevent the effects of hypoxia on EEG and nerve conduction velocity (NCV). 35 adult Wistar albino male rats were divided into five groups (n=7): control (C), hypoxia (H), hypoxia and exercise (HE), hypoxia and DHA (HD), and hypoxia and exercise and DHA (HED) groups. During the 28-day hypoxia exposure, the HE and HED groups of rats were exercised (0% incline, 30 m/min speed, 20 min/day, 5 days a week). In addition, DHA (36 mg/kg/day) was given by oral gavage to rats in the HD and HED groups. While EEG records were taken before and after the experimental period, NCV records were taken after the experimental period from anesthetized rats. Data were analyzed by paired t-test, one-way ANOVA, and post hoc Tukey test. In this study, it was shown that exposure to hypoxia decreased theta activity and NCV, but exercise and DHA reduced the delta activity, while theta, alpha, beta activities, and NCV were increased. These results have shown that the effects of hypoxia exposure on EEG and NCV can be prevented by exercise and/or DHA. PMID:24377343

  8. Correlated Components of Ongoing EEG Point to Emotionally Laden Attention – A Possible Marker of Engagement?

    PubMed Central

    Dmochowski, Jacek P.; Sajda, Paul; Dias, Joao; Parra, Lucas C.

    2012-01-01

    Recent evidence from functional magnetic resonance imaging suggests that cortical hemodynamic responses coincide in different subjects experiencing a common naturalistic stimulus. Here we utilize neural responses in the electroencephalogram (EEG) evoked by multiple presentations of short film clips to index brain states marked by high levels of correlation within and across subjects. We formulate a novel signal decomposition method which extracts maximally correlated signal components from multiple EEG records. The resulting components capture correlations down to a one-second time resolution, thus revealing that peak correlations of neural activity across viewings can occur in remarkable correspondence with arousing moments of the film. Moreover, a significant reduction in neural correlation occurs upon a second viewing of the film or when the narrative is disrupted by presenting its scenes scrambled in time. We also probe oscillatory brain activity during periods of heightened correlation, and observe during such times a significant increase in the theta band for a frontal component and reductions in the alpha and beta frequency bands for parietal and occipital components. Low-resolution EEG tomography of these components suggests that the correlated neural activity is consistent with sources in the cingulate and orbitofrontal cortices. Put together, these results suggest that the observed synchrony reflects attention- and emotion-modulated cortical processing which may be decoded with high temporal resolution by extracting maximally correlated components of neural activity. PMID:22623915

  9. From lab to field conditions: a pilot study on EEG methodology in applied sports sciences.

    PubMed

    Reinecke, Kirsten; Cordes, Marjolijn; Lerch, Christiane; Koutsandréou, Flora; Schubert, Michael; Weiss, Michael; Baumeister, Jochen

    2011-12-01

    Although neurophysiological aspects have become more important in sports and exercise sciences in the last years, it was not possible to measure cortical activity during performance outside a laboratory due to equipment limits or movement artifacts in particular. With this pilot study we want to investigate whether Electroencephalography (EEG) data obtained in a laboratory golf putting performance differ from a suitable putting task under field conditions. Therefore, parameters of the working memory (frontal Theta and parietal Alpha 2 power) were recorded during these two conditions. Statistical calculations demonstrated a significant difference only for Theta power at F4 regarding the two putting conditions "field" and "laboratory". These findings support the idea that brain activity patterns obtained under laboratory conditions are comparable but not equivalent to those obtained under field conditions. Additionally, we were able to show that the EEG methodology seems to be a reliable tool to observe brain activity under field conditions in a golf putting task. However, considering the still existing problems of movement artifacts during EEG measurements, eligible sports and exercises are limited to those being relatively motionless during execution. Further studies are needed to confirm these pilot results. PMID:21800184

  10. Soft, Comfortable Polymer Dry Electrodes for High Quality ECG and EEG Recording

    PubMed Central

    Chen, Yun-Hsuan; de Beeck, Maaike Op; Vanderheyden, Luc; Carrette, Evelien; Mihajlović, Vojkan; Vanstreels, Kris; Grundlehner, Bernard; Gadeyne, Stefanie; Boon, Paul; Van Hoof, Chris

    2014-01-01

    Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only ∼10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes. PMID:25513825

  11. Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.

    PubMed

    Subhani, Ahmad Rauf; Likun, Xia; Saeed Malik, Aamir

    2012-01-01

    Cerebral activation and autonomic nervous system have importance in studies such as mental stress. The aim of this study is to analyze variations in EEG scalp potential which may influence autonomic activation of heart while playing video games. Ten healthy participants were recruited in this study. Electroencephalogram (EEG) and electrocardiogram (ECG) signals were measured simultaneously during playing video game and rest conditions. Sympathetic and parasympathetic innervations of heart were evaluated from heart rate variability (HRV), derived from the ECG. Scalp potential was measured by the EEG. The results showed a significant upsurge in the value theta Fz/alpha Pz (p<0.001) while playing game. The results also showed tachycardia while playing video game as compared to rest condition (p<0.005). Normalized low frequency power and ratio of low frequency/high frequency power were significantly increased while playing video game and normalized high frequency power sank during video games. Results showed synchronized activity of cerebellum and sympathetic and parasympathetic innervation of heart. PMID:23366661

  12. Psychometric and EEG changes after carotid endarterectomy.

    PubMed

    Valenti, Pietro; Ortelli, Paola; Zanon, Antonio; Schiff, Sami; Montagnese, Sara; Avruscio, Giampietro; Del Piccolo, Franco; Mapelli, Daniela; Puato, Massimo; Rattazzi, Marcello; Amodio, Piero; Pauletto, Paolo

    2015-02-01

    The influence of carotid stenosis and its surgical treatment on brain function is still poorly defined. We therefore performed a study to assess psychometric and quantified EEG findings after carotid endarterectomy (CEA). Sixty-nine non-demented patients (aged 72 ± 7 years) with severe carotid stenosis (≥ 70%) eligible for CEA were studied. Forty patients (group A) had unilateral stenosis, and 29 patients (group B) had bilateral stenosis. Before and 5 months after CEA all the patients were evaluated by the Trail Making Test A, the Symbol Digit Test, and spectral EEG analysis. At baseline, compared to group A, group B patients performed slowly the Trail Making Test A (Z: 1.45 ± 1.4 vs. 0.76 ± 1.3; p <  0.05), but not the Symbol Digit Test (Z: 0.83 ± 1.38 vs. 0.64 ± 1.26; p = 0.59). Altogether, the patients with at least one abnormal psychometric test were 29% (group A: 26%; group B: 33%, p = 0.56). The EEG did not differ significantly between patients of group A compared to group B. After CEA, psychometric tests improved (mean Z score from 0.73 ± 1.12 to 0.45 ± 1.15, p <  0.05). The improvement was similar in group A and B. The EEG mean dominant frequency improved only in group B patients and it was related to the improvement in psychometric tests (r = 0.43, p = 0.05). Low psychometric performance was detectable in about 1/ 3 of non-demented patients with severe carotid stenosis. CEA improved mental performance and, in patients with severe bilateral stenosis, accelerated the EEG frequency. PMID:25034456

  13. Interhemispheric Asymmetries and Theta Activity in the Rostral Anterior Cingulate Cortex as EEG Signature of HIV-Related Depression: Gender Matters.

    PubMed

    Kremer, Heidemarie; Lutz, Franz P C; McIntosh, Roger C; Dévieux, Jessy G; Ironson, Gail

    2016-04-01

    Resting EEGs of 40 people living with HIV (PLWH) on long-term antiretroviral treatment were examined for z-scored deviations from a healthy control (normative database) to examine the main and interaction effects of depression and gender. Regions of interest were frontal (alpha) and central (all bands) for interhemispheric asymmetries in quantitative EEGs and theta in the rostral anterior cingulate cortex (rACC) in low-resolution electromagnetic tomography (LORETA). Z-scored normed deviations of depressed PLWH, compared with nondepressed, showed right-dominant interhemispheric asymmetries in all regions. However, after adjusting for multiple testing, significance remained only central for theta, alpha, and beta. Reversed (left-dominant) frontal alpha asymmetry is a potential EEG marker of depression in the HIV negative population that was not reversed in depressive PLWH; however, corresponding with extant literature, gender had an effect on the size of frontal alpha asymmetry. The LORETA analysis revealed a trending interactional effect of depression and gender on theta activity in the rACC in Brodmann area 32. We found that compared to men, women had greater right-dominant frontal alpha-asymmetry and elevated theta activity in voxels of the rACC, which may indicate less likelihood of depression and a higher likelihood of response to antidepressants. In conclusion, subtle EEG deviations, such as right-dominant central theta, alpha, and beta asymmetries and theta activity in the rACC may mark HIV-related depressive symptoms and may predict the likelihood of response to antidepressants but gender effects need to be taken into account. Although this study introduced the use of LORETA to examine the neurophysiological correlates of negative affect in PLWH, further research is needed to assess the utility of this tool in diagnostics and treatment monitoring of depression in PLWH. PMID:25568149

  14. EEG and Neuronal Activity Topography analysis can predict effectiveness of shunt operation in idiopathic normal pressure hydrocephalus patients.

    PubMed

    Aoki, Yasunori; Kazui, Hiroaki; Tanaka, Toshihisa; Ishii, Ryouhei; Wada, Tamiki; Ikeda, Shunichiro; Hata, Masahiro; Canuet, Leonides; Musha, Toshimitsu; Matsuzaki, Haruyasu; Imajo, Kaoru; Yoshiyama, Kenji; Yoshida, Tetsuhiko; Shimizu, Yoshiro; Nomura, Keiko; Iwase, Masao; Takeda, Masatoshi

    2013-01-01

    Idiopathic normal pressure hydrocephalus (iNPH) is a neuropsychiatric syndrome characterized by gait disturbance, cognitive impairment and urinary incontinence that affect elderly individuals. These symptoms can potentially be reversed by cerebrospinal fluid (CSF) drainage or shunt operation. Prior to shunt operation, drainage of a small amount of CSF or "CSF tapping" is usually performed to ascertain the effect of the operation. Unfortunately, conventional neuroimaging methods such as single photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI), as well as electroencephalogram (EEG) power analysis seem to have failed to detect the effect of CSF tapping on brain function. In this work, we propose the use of Neuronal Activity Topography (NAT) analysis, which calculates normalized power variance (NPV) of EEG waves, to detect cortical functional changes induced by CSF tapping in iNPH. Based on clinical improvement by CSF tapping and shunt operation, we classified 24 iNPH patients into responders (N = 11) and nonresponders (N = 13), and performed both EEG power analysis and NAT analysis. We also assessed correlations between changes in NPV and changes in functional scores on gait and cognition scales before and after CSF tapping. NAT analysis showed that after CSF tapping there was a significant decrease in alpha NPV at the medial frontal cortex (FC) (Fz) in responders, while nonresponders exhibited an increase in alpha NPV at the right dorsolateral prefrontal cortex (DLPFC) (F8). Furthermore, we found correlations between cortical functional changes and clinical symptoms. In particular, delta and alpha NPV changes in the left-dorsal FC (F3) correlated with changes in gait status, while alpha and beta NPV changes in the right anterior prefrontal cortex (PFC) (Fp2) and left DLPFC (F7) as well as alpha NPV changes in the medial FC (Fz) correlated with changes in gait velocity. In addition, alpha NPV changes in the right DLPFC (F

  15. Decoding and Reconstructing the Focus of Spatial Attention from the Topography of Alpha-band Oscillations.

    PubMed

    Samaha, Jason; Sprague, Thomas C; Postle, Bradley R

    2016-08-01

    Many aspects of perception and cognition are supported by activity in neural populations that are tuned to different stimulus features (e.g., orientation, spatial location, color). Goal-directed behavior, such as sustained attention, requires a mechanism for the selective prioritization of contextually appropriate representations. A candidate mechanism of sustained spatial attention is neural activity in the alpha band (8-13 Hz), whose power in the human EEG covaries with the focus of covert attention. Here, we applied an inverted encoding model to assess whether spatially selective neural responses could be recovered from the topography of alpha-band oscillations during spatial attention. Participants were cued to covertly attend to one of six spatial locations arranged concentrically around fixation while EEG was recorded. A linear classifier applied to EEG data during sustained attention demonstrated successful classification of the attended location from the topography of alpha power, although not from other frequency bands. We next sought to reconstruct the focus of spatial attention over time by applying inverted encoding models to the topography of alpha power and phase. Alpha power, but not phase, allowed for robust reconstructions of the specific attended location beginning around 450 msec postcue, an onset earlier than previous reports. These results demonstrate that posterior alpha-band oscillations can be used to track activity in feature-selective neural populations with high temporal precision during the deployment of covert spatial attention. PMID:27003790

  16. Rapid EEG desynchronization and EMG activation induced by intravenous cocaine in freely moving rats: a peripheral, nondopamine neural triggering.

    PubMed

    Kiyatkin, Eugene A; Smirnov, Michael S

    2010-02-01

    Many important physiological, behavioral, and psychoemotional effects of intravenous (IV) cocaine (COC) are too fast and transient compared with pharmacokinetic predictions, suggesting a possible involvement of peripheral neural mechanisms in their triggering. In the present study, we examined changes in cortical electroencephalogram (EEG) and neck electromyogram (EMG) induced in freely moving rats by IV COC administration at low, reinforcing doses (0.25-1.0 mg/kg) and compared them with those induced by an auditory stimulus and IV COC methiodide, which cannot cross the blood-brain barrier. We found that COC induces rapid, strong, and prolonged EEG desynchronization, associated with decrease in alpha and increase in beta and gamma activities, and EMG activation and that both begin within 2-6 s following the start of a 10-s injection; immediate components of this effect were dose independent. The rapid COC-induced changes in EEG and EMG resembled those induced by an auditory stimulus; the latter effects had shorter onset latencies and durations and were fully blocked during urethane anesthesia. Although urethane anesthesia completely blocked COC-induced EMG activation and rapid components of EEG response, COC still induced EEG desynchronization that was much weaker, greatly delayed (approximately 60 s), and associated with tonic decreases in delta and increases in alpha, beta, and gamma activities. Surprisingly, IV saline delivered during slow-wave sleep (but not quite wakefulness) also induced a transient EEG desynchronization but without changes in EMG activity; these effects were also fully blocked during anesthesia. Peripherally acting COC methiodide fully mimicked rapid EEG and EMG effects of regular COC, but the effects at an equimolar dose were less prolonged than those with regular COC. These data suggest that in awake animals IV COC, like somato-sensory stimuli, induces cortical activation and a subsequent motor response via its action on peripheral neural

  17. Screening EEG in Aircrew Selection: Clinical Aerospace Neurology Perspective

    NASA Technical Reports Server (NTRS)

    Clark, Jonathan B.; Riley, Terrence

    2001-01-01

    As clinical aerospace neurologists we do not favor using screening EEG in pilot selection on unselected and otherwise asymptomatic individuals. The role of EEG in aviation screening should be as an adjunct to diagnosis, and the decision to disqualify a pilot should never be based solely on the EEG. Although a policy of using a screening EEG in an unselected population might detect an individual with a potentially increased relative risk, it would needlessly exclude many applicants who would probably never have a seizure. A diagnostic test performed on an asymptomatic individual without clinical indications, in a population with a low prevalence of disease (seizure) may be of limited or possibly detrimental value. We feel that rather than do EEGs on all candidates, a better approach would be to perform an EEG for a specific indication, such as family history of seizure, single convulsion (seizure) , history of unexplained loss of consciousness or head injury. Routine screening EEGs in unselected aviation applications are not done without clinical indication in the U.S. Air Force, Navy, or NASA. The USAF discontinued routine screening EEGs for selection in 1978, the U.S. Navy discontinued it in 1981 , and NASA discontinued it in 1995. EEG as an aeromedical screening tool in the US Navy dates back to 1939. The US Navy routinely used EEGs to screen all aeromedical personnel from 1961 to 1981. The incidence of epileptiform activity on EEG in asymptomatic flight candidates ranges from 0.11 to 2.5%. In 3 studies of asymptomatic flight candidates with epileptiform activity on EEG followed for 2 to 15 years, 1 of 31 (3.2%), 1 of 30 (3.3%), and 0 of 14 (0%) developed a seizure, for a cumulative risk of an individual with an epileptiform EEG developing a seizure of 2.67% (2 in 75). Of 28,658 student naval aviation personnel screened 31 had spikes and/or slow waves on EEG, and only 1 later developed a seizure. Of the 28,627 who had a normal EEG, 4 later developed seizures, or

  18. Standardized EEG interpretation accurately predicts prognosis after cardiac arrest

    PubMed Central

    Rossetti, Andrea O.; van Rootselaar, Anne-Fleur; Wesenberg Kjaer, Troels; Horn, Janneke; Ullén, Susann; Friberg, Hans; Nielsen, Niklas; Rosén, Ingmar; Åneman, Anders; Erlinge, David; Gasche, Yvan; Hassager, Christian; Hovdenes, Jan; Kjaergaard, Jesper; Kuiper, Michael; Pellis, Tommaso; Stammet, Pascal; Wanscher, Michael; Wetterslev, Jørn; Wise, Matt P.; Cronberg, Tobias

    2016-01-01

    Objective: To identify reliable predictors of outcome in comatose patients after cardiac arrest using a single routine EEG and standardized interpretation according to the terminology proposed by the American Clinical Neurophysiology Society. Methods: In this cohort study, 4 EEG specialists, blinded to outcome, evaluated prospectively recorded EEGs in the Target Temperature Management trial (TTM trial) that randomized patients to 33°C vs 36°C. Routine EEG was performed in patients still comatose after rewarming. EEGs were classified into highly malignant (suppression, suppression with periodic discharges, burst-suppression), malignant (periodic or rhythmic patterns, pathological or nonreactive background), and benign EEG (absence of malignant features). Poor outcome was defined as best Cerebral Performance Category score 3–5 until 180 days. Results: Eight TTM sites randomized 202 patients. EEGs were recorded in 103 patients at a median 77 hours after cardiac arrest; 37% had a highly malignant EEG and all had a poor outcome (specificity 100%, sensitivity 50%). Any malignant EEG feature had a low specificity to predict poor prognosis (48%) but if 2 malignant EEG features were present specificity increased to 96% (p < 0.001). Specificity and sensitivity were not significantly affected by targeted temperature or sedation. A benign EEG was found in 1% of the patients with a poor outcome. Conclusions: Highly malignant EEG after rewarming reliably predicted poor outcome in half of patients without false predictions. An isolated finding of a single malignant feature did not predict poor outcome whereas a benign EEG was highly predictive of a good outcome. PMID:26865516

  19. Abnormal Parietal Brain Function in ADHD: Replication and Extension of Previous EEG Beta Asymmetry Findings

    PubMed Central

    Hale, T. Sigi; Kane, Andrea M.; Tung, Kelly L.; Kaminsky, Olivia; McGough, James J.; Hanada, Grant; Loo, Sandra K.

    2014-01-01

    Background: Abundant work indicates ADHD abnormal posterior brain structure and function, including abnormal structural and functional asymmetries and reduced corpus callosum size. However, this literature has attracted considerably less research interest than fronto-striatal findings. Objective: To help address this imbalance, the current study replicates and extends our previous work showing abnormal parietal brain function in ADHD adults during the Conner’s Continuous Performance Test (CPT). Method: Our previous study found that ADHD adults had increased rightward EEG beta (16–21 Hz) asymmetry in inferior parietal brain regions during the CPT (p = 0.00001), and that this metric exhibited a lack of normal correlation (i.e., observed in controls) with beta asymmetry at temporal–parietal regions. We re-tested these effects in a new ADHD sample and with both new and old samples combined. We additionally examined: (a) EEG asymmetry in multiple frequency bands, (b) unilateral effects for all asymmetry findings, and (c) the association between EEG asymmetry and a battery of cognitive tests. Results: We replicated our original findings by demonstrating abnormal rightward inferior parietal beta asymmetry in adults with ADHD during the CPT, and again this metric exhibited abnormal reduced correlation to temporal–parietal beta asymmetry. Novel analyses also demonstrated a broader pattern of rightward beta and theta asymmetry across inferior, superior, and temporal–parietal brain regions, and showed that rightward parietal asymmetry in ADHD was atypically associated with multiple cognitive tests. Conclusion: Abnormal increased rightward parietal EEG beta asymmetry is an important feature of ADHD. We speculate that this phenotype may occur with any form of impaired capacity for top-down task-directed control over sensory encoding functions, and that it may reflect associated increase of attentional shifting and compensatory sustained/selective attention. PMID

  20. Ecological validity of neurofeedback: modulation of slow wave EEG enhances musical performance.

    PubMed

    Egner, Tobias; Gruzelier, John H

    2003-07-01

    Biofeedback-assisted modulation of electrocortical activity has been established to have intrinsic clinical benefits and has been shown to improve cognitive performance in healthy humans. In order to further investigate the pedagogic relevance of electroencephalograph (EEG) biofeedback (neurofeedback) for enhancing normal function, a series of investigations assessed the training's impact on an ecologically valid real-life behavioural performance measure: music performance under stressful conditions in conservatoire students. In a pilot study, single-blind expert ratings documented improvements in musical performance in a student group that received training on attention and relaxation related neurofeedback protocols, and improvements were highly correlated with learning to progressively raise theta (5-8 Hz) over alpha (8-11 Hz) band amplitudes. These findings were replicated in a second experiment where an alpha/theta training group displayed significant performance enhancement not found with other neurofeedback training protocols or in alternative interventions, including the widely applied Alexander technique. PMID:12824763

  1. Quantitative EEG: investigation in children with end stage renal disease before and after haemodialysis.

    PubMed

    Balzar, E; Saletu, B; Khoss, A; Wagner, U

    1986-10-01

    Changes in brain function of 9 children (6 males and 3 females) ages 7 to 14 years (mean 12 years) with end stage renal disease (ESRD) were investigated before and after haemodialysis treatment, utilizing computer assisted spectral analysis of the scalp-recorded EEG. A control group of age-matched healthy children was studied as well. Statistical analyses demonstrated that ESRD children exhibited more Delta and Theta activity, less Beta activity, a slower dominant frequency of the Alpha activity as well as a slower centroid of the total activity before treatment than the controls. These findings suggest a deterioration of vigilance as characterized by Head. Haemodialysis decreased slow activity and increased Alpha and Beta activity, thereby inducing an improvement of brain function. PMID:3791647

  2. Cross coherence independent component analysis in resting and action states EEG discrimination

    NASA Astrophysics Data System (ADS)

    Almurshedi, A.; Ismail, A. K.

    2014-11-01

    Cross Coherence time frequency transform and independent component analysis (ICA) method were used to analyse the electroencephalogram (EEG) signals in resting and action states during open and close eyes conditions. From the topographical scalp distributions of delta, theta, alpha, and beta power spectrum can clearly discriminate between the signal when the eyes were open or closed, but it was difficult to distinguish between resting and action states when the eyes were closed. In open eyes condition, the frontal area (Fp1, Fp2) was activated (higher power) in delta and theta bands whilst occipital (O1, O2) and partial (P3, P4, Pz) area of brain was activated alpha band in closed eyes condition. The cross coherence method of time frequency analysis is capable of discrimination between rest and action brain signals in closed eyes condition.

  3. Spatiotemporal analysis of prepyriform, visual, auditory, and somesthetic surface EEGs in trained rabbits.

    PubMed

    Barrie, J M; Freeman, W J; Lenhart, M D

    1996-07-01

    1. Spatial ensemble averages were computed for 64 traces of electroencephalograms (EEGs) simultaneously recorded from 8 x 8 arrays over the epidural surfaces of the prepyriform cortex (PPC) and visual, somatic, and auditory cortices. They revealed a common waveform across each array. Examination of the spatial amplitude modulation (AM) of the waveform revealed classifiable spatial pattern in short time segments. The AM patterns varied within trials after presentation of identical conditioned stimuli, and also between trials with differing stimuli. 2. PPC EEGs revealed strong correlates with the respiratory rhythm; neocortical EEGs did not. 3. Time ensemble averaging of the PPC EEG attenuated the oscillatory bursts, indicating that olfactory gamma oscillations (20-80 Hz) were not phase-locked to the times of stimulus delivery but instead to inhalations. Time ensemble averages of neocortical recordings across trials revealed average evoked potentials starting 30-50 ms after the arrival of the stimulus. 4. Average temporal fast Fourier transform (FFT) power spectral densities (PSDs) from pre- and poststimulus PPC EEG segments revealed a peak of gamma activity in olfactory bursts. 5. The logarithm of the average temporal FFT PSDs from pre- and poststimulus neocortical EEG segments, when plotted against log frequency, revealed 1/f-type spectra in both pre- and poststimulus segments for negative/aversive conditioned stimuli (CS-) and positive/rewarding conditioned stimuli (CS+). The alpha'- and beta'-coefficients from the regression of Eq. 2 onto the average PSDs were significantly different between pre- and poststimulus segments, owing to the evoked potentials, but not between CS- and CS+ stimulus segments. 6. Spatiotemporal patterns were invariant over all frequency bins in the 1/f domain (20-100 Hz). Spatiotemporal patterns in the 2- to 20-Hz domain progressively differed from the invariant patterns with decreasing frequency. 7. In the spatial frequency domain, the

  4. The Voice of Anger: Oscillatory EEG Responses to Emotional Prosody.

    PubMed

    Del Giudice, Renata; Blume, Christine; Wislowska, Malgorzata; Wielek, Tomasz; Heib, Dominik P J; Schabus, Manuel

    2016-01-01

    Emotionally relevant stimuli and in particular anger are, due to their evolutionary relevance, often processed automatically and able to modulate attention independent of conscious access. Here, we tested whether attention allocation is enhanced when auditory stimuli are uttered by an angry voice. We recorded EEG and presented healthy individuals with a passive condition where unfamiliar names as well as the subject's own name were spoken both with an angry and neutral prosody. The active condition instead, required participants to actively count one of the presented (angry) names. Results revealed that in the passive condition the angry prosody only elicited slightly stronger delta synchronization as compared to a neutral voice. In the active condition the attended (angry) target was related to enhanced delta/theta synchronization as well as alpha desynchronization suggesting enhanced allocation of attention and utilization of working memory resources. Altogether, the current results are in line with previous findings and highlight that attention orientation can be systematically related to specific oscillatory brain responses. Potential applications include assessment of non-communicative clinical groups such as post-comatose patients. PMID:27442445

  5. The Voice of Anger: Oscillatory EEG Responses to Emotional Prosody

    PubMed Central

    del Giudice, Renata; Blume, Christine; Wislowska, Malgorzata; Wielek, Tomasz; Heib, Dominik P. J.; Schabus, Manuel

    2016-01-01

    Emotionally relevant stimuli and in particular anger are, due to their evolutionary relevance, often processed automatically and able to modulate attention independent of conscious access. Here, we tested whether attention allocation is enhanced when auditory stimuli are uttered by an angry voice. We recorded EEG and presented healthy individuals with a passive condition where unfamiliar names as well as the subject’s own name were spoken both with an angry and neutral prosody. The active condition instead, required participants to actively count one of the presented (angry) names. Results revealed that in the passive condition the angry prosody only elicited slightly stronger delta synchronization as compared to a neutral voice. In the active condition the attended (angry) target was related to enhanced delta/theta synchronization as well as alpha desynchronization suggesting enhanced allocation of attention and utilization of working memory resources. Altogether, the current results are in line with previous findings and highlight that attention orientation can be systematically related to specific oscillatory brain responses. Potential applications include assessment of non-communicative clinical groups such as post-comatose patients. PMID:27442445

  6. Judgment of actions in experts: a high-resolution EEG study in elite athletes.

    PubMed

    Babiloni, Claudio; Del Percio, Claudio; Rossini, Paolo M; Marzano, Nicola; Iacoboni, Marco; Infarinato, Francesco; Lizio, Roberta; Piazza, Marina; Pirritano, Mirella; Berlutti, Giovanna; Cibelli, Giuseppe; Eusebi, Fabrizio

    2009-04-01

    The present study tested the two following hypotheses: (i) compared to non-athletes, elite athletes are characterized by a reduced cortical activation during the judgment of sporting observed actions; (ii) in elite athletes, a good judgment of observed sporting actions is related to a low cortical activation. To address these issues, electroencephalographic (EEG) data were recorded in 15 elite rhythmic gymnasts and 13 non-gymnasts. They observed a series of 120 rhythmic gymnastic videos. At the end of each video, the subjects had to judge the artistic/athletic level of the exercise by a scale from 0 to 10. The mismatch between their judgment and that of the coach indexed the degree of action judgment. The EEG cortical sources were estimated by sLORETA. With reference to a pre-stimulus period, the power decrease of alpha (8-12 Hz) rhythms during the videos indexed the cortical activation (event related desynchronization, ERD). Regarding the hypothesis (i), low- and high-frequency alpha ERD was lower in amplitude in the elite rhythmic gymnasts compared to the non-gymnasts in occipital and temporal areas (ventral pathway) and in dorsal pathway. Regarding the hypothesis (ii), in the elite rhythmic gymnasts high-frequency alpha ERD was higher in amplitude with the videos characterized by a high judgment error than those characterized by a low judgment error; this was true in inferior posterior parietal and ventral premotor areas ("mirror" pathway). These results globally suggest that the judgment of observed sporting actions is related to low amplitude of alpha ERD, as a possible index of spatially selective cortical activation ("neural efficiency"). PMID:19111623

  7. EEG frequency analysis of cortical brain activities induced by effect of light touch.

    PubMed

    Ishigaki, Tomoya; Ueta, Kozo; Imai, Ryota; Morioka, Shu

    2016-06-01

    In human postural control, touching a fingertip to a stable object with a slight force (<1 N) reduces postural sway independent of mechanical support, which is referred to as the effect of light touch (LT effect). The LT effect is achieved by the spatial orientation according to haptic feedback acquired from an external spatial reference. However, the neural mechanism of the LT effect is incompletely understood. Therefore, the purpose of this study was to employ EEG frequency analysis to investigate the cortical brain activity associated with the LT effect when attentional focus was strictly controlled with the eyes closed during standing (i.e., control, fixed-point touch, sway-referenced touch, and only fingertip attention). We used EEG to measure low-alpha (about 8-10 Hz) and high-alpha rhythm (about 10-12 Hz) task-related power decrease/increase (TRPD/TRPI). The LT effect was apparent only when the subject acquired the stable external spatial reference (i.e., fixed-point touch). Furthermore, the LT-specific effect increased the high-alpha TRPD of two electrodes (C3, P3), which were mainly projected from cortical brain activities of the left primary sensorimotor cortex area and left posterior parietal cortex area. Furthermore, there was a negative correlation between the LT effect and increased TRPD of C3. In contrast, the LT effect correlated positively with increased TRPD of P3. These results suggest that central and parietal high-alpha TRPD of the contralateral hemisphere reflects the sensorimotor information processing and sensory integration for the LT effect. These novel findings reveal a partial contribution of a cortical neural mechanism for the LT effect. PMID:26758719

  8. Analysis of the time series of the EEG frequency spectra and of EEG spectral power densities.

    PubMed

    Dvorák, J; Formánek, J; Kubát, J; Plevová, J; Vanícková, M; Fires, M; Andél, J; Cipra, T; Tomásek, L; Prásková, Z; Holoubková, E; Fabián, Z

    1981-06-01

    Some examples of the use of the principal component model for the economic description of the structure of the multiple time series and for the data reduction in the quantitative EEG studies are presented. The broad-band EEG frequency spectra were measured with the use of an electronic system designed by J. Dvorák. The EEG spectral power densities were computed via the discrete Fourier Transform (namely FFT) algorithm. The estimated two or three first principal components account for the major part of the total variance of individual EEG variables: The results hold for the used elementary epoch of measurement, i.e. 5 sec. - With the use of the algorithms and FORTRAN IV programs developed by J. Andĕl, T. Cipra and L. Tomásek a data reduction by a factor of 1:2000 can be achieved without any substantial loss of biological information. - The described methods help to obtain a better insight into the structure of the data and represent a powerful tool for data reduction at least in a certain class of experimental EEG studies (experimental toxicology, pharmacology, experimental neurology). PMID:7270023

  9. Preliteracy signatures of poor-reading abilities in resting-state EEG.

    PubMed

    Schiavone, Giuseppina; Linkenkaer-Hansen, Klaus; Maurits, Natasha M; Plakas, Anna; Maassen, Ben A M; Mansvelder, Huibert D; van der Leij, Aryan; van Zuijen, Titia L

    2014-01-01

    The hereditary character of dyslexia suggests the presence of putative underlying neural anomalies already in preliterate age. Here, we investigated whether early neurophysiological correlates of future reading difficulties-a hallmark of dyslexia-could be identified in the resting-state EEG of preliterate children. The children in this study were recruited at birth and classified on the basis of parents' performance on reading tests to be at-risk of becoming poor readers (n = 48) or not (n = 14). Eyes-open rest EEG was measured at the age of 3 years, and the at-risk children were divided into fluent readers (n = 24) and non-fluent readers (n = 24) after reading assessment at their third grade of school. We found that fluent readers and non-fluent readers differed in normalized spectral amplitude. Non-fluent readers were characterized by lower amplitude in the delta-1 frequency band (0.5-2 Hz) and higher amplitude in the alpha-1 band (6-8 Hz) in multiple scalp regions compared to control and at-risk fluent readers. Interestingly, across groups these EEG biomarkers correlated with several behavioral test scores measured in the third grade. Specifically, the performance on reading fluency, phonological and orthographic tasks and rapid automatized naming task correlated positively with delta-1 and negatively with alpha-1. Together, our results suggest that combining family-risk status, neurophysiological testing and behavioral test scores in a longitudinal setting may help uncover physiological mechanisms implicated with neurodevelopmental disorders such as the predisposition to reading disabilities. PMID:25285075

  10. Noisy galvanic vestibular stimulation modulates the amplitude of EEG synchrony patterns.

    PubMed

    Kim, Diana J; Yogendrakumar, Vignan; Chiang, Joyce; Ty, Edna; Wang, Z Jane; McKeown, Martin J

    2013-01-01

    Noisy galvanic vestibular stimulation has been associated with numerous cognitive and behavioural effects, such as enhancement of visual memory in healthy individuals, improvement of visual deficits in stroke patients, as well as possibly improvement of motor function in Parkinson's disease; yet, the mechanism of action is unclear. Since Parkinson's and other neuropsychiatric diseases are characterized by maladaptive dynamics of brain rhythms, we investigated whether noisy galvanic vestibular stimulation was associated with measurable changes in EEG oscillatory rhythms within theta (4-7.5 Hz), low alpha (8-10 Hz), high alpha (10.5-12 Hz), beta (13-30 Hz) and gamma (31-50 Hz) bands. We recorded the EEG while simultaneously delivering noisy bilateral, bipolar stimulation at varying intensities of imperceptible currents - at 10, 26, 42, 58, 74 and 90% of sensory threshold - to ten neurologically healthy subjects. Using standard spectral analysis, we investigated the transient aftereffects of noisy stimulation on rhythms. Subsequently, using robust artifact rejection techniques and the Least Absolute Shrinkage Selection Operator regression and cross-validation, we assessed the combinations of channels and power spectral features within each EEG frequency band that were linearly related with stimulus intensity. We show that noisy galvanic vestibular stimulation predominantly leads to a mild suppression of gamma power in lateral regions immediately after stimulation, followed by delayed increase in beta and gamma power in frontal regions approximately 20-25 s after stimulation ceased. Ongoing changes in the power of each oscillatory band throughout frontal, central/parietal, occipital and bilateral electrodes predicted the intensity of galvanic vestibular stimulation in a stimulus-dependent manner, demonstrating linear effects of stimulation on brain rhythms. We propose that modulation of neural oscillations is a potential mechanism for the previously-described cognitive

  11. Decreased Modulation of EEG Oscillations in High-Functioning Autism during a Motor Control Task.

    PubMed

    Ewen, Joshua B; Lakshmanan, Balaji M; Pillai, Ajay S; McAuliffe, Danielle; Nettles, Carrie; Hallett, Mark; Crone, Nathan E; Mostofsky, Stewart H

    2016-01-01

    Autism spectrum disorders (ASD) are thought to result in part from altered cortical excitatory-inhibitory balance; this pathophysiology may impact the generation of oscillations on electroencephalogram (EEG). We investigated premotor-parietal cortical physiology associated with praxis, which has strong theoretical and empirical associations with ASD symptomatology. Twenty five children with high-functioning ASD (HFA) and 33 controls performed a praxis task involving the pantomiming of tool use, while EEG was recorded. We assessed task-related modulation of signal power in alpha and beta frequency bands. Compared with controls, subjects with HFA showed 27% less left central (motor/premotor) beta (18-22 Hz) event-related desynchronization (ERD; p = 0.030), as well as 24% less left parietal alpha (7-13 Hz) ERD (p = 0.046). Within the HFA group, blunting of central ERD attenuation was associated with impairments in clinical measures of praxis imitation (r = -0.4; p = 0.04) and increased autism severity (r = 0.48; p = 0.016). The modulation of central beta activity is associated, among other things, with motor imagery, which may be necessary for imitation. Impaired imitation has been associated with core features of ASD. Altered modulation of oscillatory activity may be mechanistically involved in those aspects of motor network function that relate to the core symptoms of ASD. PMID:27199719

  12. Biophysical model for integrating neuronal activity, EEG, fMRI and metabolism.

    PubMed

    Sotero, Roberto C; Trujillo-Barreto, Nelson J

    2008-01-01

    Our goal is to model the coupling between neuronal activity, cerebral metabolic rates of glucose and oxygen consumption, cerebral blood flow (CBF), electroencephalography (EEG) and blood oxygenation level-dependent (BOLD) responses. In order to accomplish this, two previous models are coupled: a metabolic/hemodynamic model (MHM) for a voxel, linking BOLD signals and neuronal activity, and a neural mass model describing the neuronal dynamics within a voxel and its interactions with voxels of the same area (short-range interactions) and other areas (long-range interactions). For coupling both models, we take as the input to the BOLD model, the number of active synapses within the voxel, that is, the average number of synapses that will receive an action potential within the time unit. This is obtained by considering the action potentials transmitted between neuronal populations within the voxel, as well as those arriving from other voxels. Simulations are carried out for testing the integrated model. Results show that realistic evoked potentials (EP) at electrodes on the scalp surface and the corresponding BOLD signals for each voxel are produced by the model. In another simulation, the alpha rhythm was reproduced and reasonable similarities with experimental data were obtained when calculating correlations between BOLD signals and the alpha power curve. The origin of negative BOLD responses and the characteristics of EEG, PET and BOLD signals in Alzheimer's disease were also studied. PMID:17919931

  13. Neuronal Correlates of Maladaptive Coping: An EEG-Study in Tinnitus Patients

    PubMed Central

    Vanneste, Sven; Joos, Kathleen; Langguth, Berthold; To, Wing Ting; De Ridder, Dirk

    2014-01-01

    Here we aimed to investigate the neuronal correlates of different coping styles in patients suffering from chronic tinnitus. Adaptive and maladaptive coping styles were determined in 85 tinnitus patients. Based on resting state EEG recordings, coping related differences in brain activity and connectivity were found. Maladaptive coping behavior was related to increases in subjective tinnitus loudness and distress, higher tinnitus severity and higher depression scores. EEG recordings demonstrated increased alpha activity over the left dorsolateral prefrontal cortex (DLPFC) and subgenual anterior cingulate cortex (sgACC) as well as increased connectivity in the default (i.e. resting state) network in tinnitus patients with a maladaptive coping style. Correlation analysis revealed that the changes in the DLPFC correlate primarily with maladaptive coping behavior, whereas the changes in the sgACC correlate with tinnitus severity and depression. Our findings are in line with previous research in the field of depression that during resting state a alpha band hyperconnectivity exists within the default network for patients who use a maladaptive coping style, with the sgACC as the dysfunctional node and that the strength of the connectivity is related to focusing on negative mood and catastrophizing about the consequences of tinnitus. PMID:24558383

  14. Complexity of visual stimuli and non-linear EEG dynamics in humans.

    PubMed

    Müller, Viktor; Lutzenberger, Werner; Preissl, Hubert; Pulvermüller, Friedemann; Birbaumer, Niels

    2003-03-01

    The effects of stimulus complexity on the nonlinear electrical brain (EEG) dynamics were investigated in a sample of 24 healthy volunteers. Stimuli used were either a single mechanical low-friction pendulum with a periodic movement (temporal frequency about 1 Hz) or a double-pendulum with a chaotic movement, which were observed for 2-3 min in each case. The prediction that a more complex visual stimulus (double-pendulum) increases the dimensional complexity of brain activity as compared to a simple visual stimulus (single-pendulum), was confirmed by determination of pointwise correlation dimension. Further, there was a significant decrease of alpha power in the double-pendulum compared to a single-pendulum condition. Moreover, a correlation analysis showed a positive correlation between EEG complexity and beta power over the whole cortex in the single- and, above all, in the double-pendulum condition, and also a positive correlation between dimensional complexity and alpha power in the double-pendulum condition only, particularly in the brain regions responsible for the 'bottom-up' sustained attention processes. PMID:12589895

  15. Independent component analysis of EEG dipole source localization in resting and action state of brain

    NASA Astrophysics Data System (ADS)

    Almurshedi, Ahmed; Ismail, Abd Khamim

    2015-04-01

    EEG source localization was studied in order to determine the location of the brain sources that are responsible for the measured potentials at the scalp electrodes using EEGLAB with Independent Component Analysis (ICA) algorithm. Neuron source locations are responsible in generating current dipoles in different states of brain through the measured potentials. The current dipole sources localization are measured by fitting an equivalent current dipole model using a non-linear optimization technique with the implementation of standardized boundary element head model. To fit dipole models to ICA components in an EEGLAB dataset, ICA decomposition is performed and appropriate components to be fitted are selected. The topographical scalp distributions of delta, theta, alpha, and beta power spectrum and cross coherence of EEG signals are observed. In close eyes condition it shows that during resting and action states of brain, alpha band was activated from occipital (O1, O2) and partial (P3, P4) area. Therefore, parieto-occipital area of brain are active in both resting and action state of brain. However cross coherence tells that there is more coherence between right and left hemisphere in action state of brain than that in the resting state. The preliminary result indicates that these potentials arise from the same generators in the brain.

  16. Preliminary study of Alzheimer's Disease diagnosis based on brain electrical signals using wireless EEG

    NASA Astrophysics Data System (ADS)

    Handayani, N.; Akbar, Y.; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, W. P.

    2016-03-01

    This research aims to study brain's electrical signals recorded using EEG as a basis for the diagnosis of patients with Alzheimer's Disease (AD). The subjects consisted of patients with AD, and normal subjects are used as the control. Brain signals are recorded for 3 minutes in a relaxed condition and with eyes closed. The data is processed using power spectral analysis, brain mapping and chaos test to observe the level of complexity of EEG's data. The results show a shift in the power spectral in the low frequency band (delta and theta) in AD patients. The increase of delta and theta occurs in lobus frontal area and lobus parietal respectively. However, there is a decrease of alpha activity in AD patients where in the case of normal subjects with relaxed condition, brain alpha wave dominates the posterior area. This is confirmed by the results of brain mapping. While the results of chaos analysis show that the average value of MMLE is lower in AD patients than in normal subjects. The level of chaos associated with neural complexity in AD patients with lower neural complexity is due to neuronal damage caused by the beta amyloid plaques and tau protein in neurons.

  17. Decreased Modulation of EEG Oscillations in High-Functioning Autism during a Motor Control Task

    PubMed Central

    Ewen, Joshua B.; Lakshmanan, Balaji M.; Pillai, Ajay S.; McAuliffe, Danielle; Nettles, Carrie; Hallett, Mark; Crone, Nathan E.; Mostofsky, Stewart H.

    2016-01-01

    Autism spectrum disorders (ASD) are thought to result in part from altered cortical excitatory-inhibitory balance; this pathophysiology may impact the generation of oscillations on electroencephalogram (EEG). We investigated premotor-parietal cortical physiology associated with praxis, which has strong theoretical and empirical associations with ASD symptomatology. Twenty five children with high-functioning ASD (HFA) and 33 controls performed a praxis task involving the pantomiming of tool use, while EEG was recorded. We assessed task-related modulation of signal power in alpha and beta frequency bands. Compared with controls, subjects with HFA showed 27% less left central (motor/premotor) beta (18–22 Hz) event-related desynchronization (ERD; p = 0.030), as well as 24% less left parietal alpha (7–13 Hz) ERD (p = 0.046). Within the HFA group, blunting of central ERD attenuation was associated with impairments in clinical measures of praxis imitation (r = −0.4; p = 0.04) and increased autism severity (r = 0.48; p = 0.016). The modulation of central beta activity is associated, among other things, with motor imagery, which may be necessary for imitation. Impaired imitation has been associated with core features of ASD. Altered modulation of oscillatory activity may be mechanistically involved in those aspects of motor network function that relate to the core symptoms of ASD. PMID:27199719

  18. EEG aspects of mentally playing an instrument.

    PubMed

    Petsche, H; von Stein, A; Filz, O

    1996-03-01

    This pilot study examines the possibility to detect activities of SMA by means of EEG coherence analysis in a female professional violoncellist. The proband was asked, for 5 min each, to listen to a piece of music (she knew by heart), to imagine playing this piece and to imagine playing scales. The experiment was repeated after 5 days. Consistent significant coherence changes with respect to the averaged EEG at rest were plotted as probability maps. For each of these three tasks different coherence patterns emerged. Among the electrodes next to SMA, Fz was most involved while playing scales, less while imagining playing the same piece and still less while just listening to it. PMID:8713552

  19. EEG and autonomic arousal measures in schizophrenics.

    PubMed

    Joseph, C

    1989-04-01

    EEG and autonomic indices were measured in basal, tonic, and phasic conditions in order to delineate the nature of arousal dysfunction in schizophrenics as compared to normals. The experimental procedure involved six continuous recording sessions consisting of a basal recording before and after four experimental series. Sequentially, these were the visual nonsignal (VNS), the auditory nonsignal (ANS), the visual signal (VS), and the auditory signal (AS) series. The main findings indicated significant differences between the two groups in cardiovascular indices during the basal and tonic conditions and in the EEG and EMG indices of phasic response. These results suggest a dysfunction of basal and tonic autonomic arousal and a modulatory impairement of the central phasic arousal reaction. The findings are in accordance with the two arousal hypothesis postulated by Routtenberg (1968) and disconfirm the unitary concept of arousal for the explanation of psychophysiological abnormality in schizophrenia. PMID:2744968

  20. Interhemispheric differences in awake and sleep human EEG: a comparison between non-linear and spectral measures.

    PubMed

    Pereda, E; Gamundi, A; Nicolau, M C; Rial, R; González, J

    1999-03-19

    Interhemispheric differences in the EEG of nine healthy right-handed human subjects (C3 vs. C4 derivations) were investigated during resting wake with closed eyes (CE) and sleep stages I, II, III, IV and REM. The harmonic power spectral density within the EEG main spectral bands, the fractal (Dr) and the correlation (D2) dimension as well as the largest Lyapunov exponent (lambda1) of both hemispheres were compared. In addition, the relationships between non-linear and spectral measures were analyzed. Dr, D2, lambda1 and the power in alpha band exhibited interhemispheric differences during waking, the values from the right hemisphere (RH) being higher than those of the left (LH) except for lambda1. During slow wave sleep (SWS), non-linear parameters detected opposite EEG asymmetries (D2 in stage III and lambda1 in stage IV) to those found in the other behavioural stages. In addition, both D2 and lambda1 were correlated (negatively) with the power in the delta band, but lambda1 was also correlated (positively) with the power in the alpha and beta bands. In conclusion, RH appears to be more complex though more predictable than the LH during CE and sleep stages I and II, these characteristics changing to the LH during SWS. PMID:10218905

  1. A novel self-guided approach to alpha activity training.

    PubMed

    van Boxtel, Geert J M; Denissen, Ad J M; Jäger, Mark; Vernon, David; Dekker, Marian K J; Mihajlović, Vojkan; Sitskoorn, Margriet M

    2012-03-01

    Fifty healthy participants took part in a double-blind placebo-controlled study in which they were either given auditory alpha activity (8-12Hz) training (N=18), random beta training (N=12), or no training at all (N=20). A novel wireless electrode system was used for training without instructions, involving water-based electrodes mounted in an audio headset. Training was applied approximately at central electrodes. Post-training measurement using a conventional full-cap EEG system revealed a 10% increase in alpha activity at posterior sites compared to pre-training levels, when using the conventional index of alpha activity and a non-linear regression fit intended to model individual alpha frequency. This statistically significant increase was present only in the group that received the alpha training, and remained evident at a 3 month follow-up session, especially under eyes open conditions where an additional 10% increase was found. In an exit interview, approximately twice as many participants in the alpha training group (53%) mentioned that the training was relaxing, compared to those in either the beta (20%) or no training (21%) control groups. Behavioural measures of stress and relaxation were indicative of effects of alpha activity training but failed to reach statistical significance. These results are discussed in terms of a lack of statistical power. Overall, results suggest that self-guided alpha activity training using this novel system is feasible and represents a step forward in the ease of instrumental conditioning of brain rhythms. PMID:22119661

  2. Study on Bayes Discriminant Analysis of EEG Data

    PubMed Central

    Shi, Yuan; He, DanDan; Qin, Fang

    2014-01-01

    Objective: In this paper, we have done Bayes Discriminant analysis to EEG data of experiment objects which are recorded impersonally come up with a relatively accurate method used in feature extraction and classification decisions. Methods: In accordance with the strength of α wave, the head electrodes are divided into four species. In use of part of 21 electrodes EEG data of 63 people, we have done Bayes Discriminant analysis to EEG data of six objects. Results In use of part of EEG data of 63 people, we have done Bayes Discriminant analysis, the electrode classification accuracy rates is 64.4%. Conclusions: Bayes Discriminant has higher prediction accuracy, EEG features (mainly αwave) extract more accurate. Bayes Discriminant would be better applied to the feature extraction and classification decisions of EEG data. PMID:25852784

  3. Development of the EEG measurement technique under exercising.

    PubMed

    Tanaka, Junya; Kimura, Mitsuhiro; Hosaka, Naoya; Sawaji, Hiroyuki; Sakakura, Kenichi; Magatani, Kazushige

    2005-01-01

    Our purpose of this research is a development of the method that detects EEG of an athlete under exercising. If EEG under exercising can be measured, we can assess the mental condition of the athlete. Usually, EEG is measured in the shield room, and a subject is required rest in bed while measurement. And it is said that measuring EEG under exercising is difficult. In this paper, we will discus about our new measuring method that can detect EEG under exercising by using independent component analysis. Five normal subjects were tested with our method, and EEG without artifact was able to measured. So, we think our new method will be useful for the research of mental condition of the athlete. PMID:17281621

  4. Hot water epilepsy: Phenotype and single photon emission computed tomography observations

    PubMed Central

    Patel, Mehul; Satishchandra, Parthasarathy; Aravinda, Hanumanthapura; Bharath, Rose D.; Sinha, Sanjib

    2014-01-01

    We studied the anatomical correlates of reflex hot water epilepsy (HWE) using multimodality investigations viz. magnetic resonance imaging (MRI), electroencephalography (EEG), and single photon emission computed tomography (SPECT). Five men (mean age: 27.0 ΁ 5.8 years) with HWE were subjected to MRI of brain, video-EEG studies, and SPECT scan. These were correlated with phenotypic presentations. Seizures could be precipitated in three patients with pouring of hot water over the head and semiology of seizures was suggestive of temporal lobe epilepsy. Ictal SPECT showed hyperperfusion in: left medial temporal — one, left lateral temporal — one, and right parietal — one. Interictal SPECT was normal in all five patients and did not help in localization. MRI and interictal EEG was normal in all the patients. The clinical and SPECT studies suggested temporal lobe as the seizure onset zone in some of the patients with HWE. PMID:25506178

  5. Lateralized modulation of posterior alpha oscillations in children.

    PubMed

    Vollebregt, Madelon A; Zumer, Johanna M; Ter Huurne, Niels; Castricum, Jesminne; Buitelaar, Jan K; Jensen, Ole

    2015-12-01

    The evidence for a functionally inhibitory role of alpha oscillations is growing stronger, mostly derived from studies in healthy adults investigating spatial attention. It remains unexplored if the modulation of alpha band oscillations plays a similar functional role in typically developing children. The aim of this study was to characterize alpha modulations in children in relation to attentional performance. To this end, the posterior alpha activity (8-12Hz) in children between 7 and 10years old was measured using EEG while they performed a visuospatial covert attention task. We found that the alpha activity decreased in the hemisphere contralateral to the attended hemifield, whereas it relatively increased in the other hemisphere. In addition, we found that the degree of lateralized alpha modulation predicted performance on the attention task by negatively predicting the response time on invalid trials. Of note, children who were behaviorally less influenced by spatial cueing also were children with a clear lateralized alpha modulation pattern, with a significantly stronger alpha lateralization in the left hemisphere than children who were influenced more by spatial cueing. In addition, a bias to the right visual field such as that commonly observed in children, was significantly smaller or absent in the children influenced least by spatial cueing. Among all children, the magnitude of this visual field bias was positively related to the ability to modulate alpha activity. In conclusion, we have shown that the pattern of alpha oscillations modulated by attention is already present in 7-10year old typically developing children. Although a similar pattern is observed in adults, the consequences for behavior are different. The fact that alpha modulation is already present at this age opens up the possibility of using hemispheric alpha lateralization as a tool to study the physiological basis of attention deficits in clinical disorders such as ADHD. PMID:26119021

  6. Alpha-1 Antitrypsin Deficiency

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (an-tee-TRIP-sin) deficiency, or AAT ... as it relates to lung disease. Overview Alpha-1 antitrypsin, also called AAT, is a protein made ...

  7. Nonlinear analysis of EEG in major depression with fractal dimensions.

    PubMed

    Akar, Saime A; Kara, Sadik; Agambayev, Sumeyra; Bilgic, Vedat

    2015-08-01

    Major depressive disorder (MDD) is a psychiatric mood disorder characterized by cognitive and functional impairments in attention, concentration, learning and memory. In order to investigate and understand its underlying neural activities and pathophysiology, EEG methodologies can be used. In this study, we estimated the nonlinearity features of EEG in MDD patients to assess the dynamical properties underlying the frontal and parietal brain activity. EEG data were obtained from 16 patients and 15 matched healthy controls. A wavelet-chaos methodology was used for data analysis. First, EEGs of subjects were decomposed into 5 EEG sub-bands by discrete wavelet transform. Then, both the Katz's and Higuchi's fractal dimensions (KFD and HFD) were calculated as complexity measures for full-band and sub-bands EEGs. Last, two-way analyses of variances were used to test EEG complexity differences on each fractality measures. As a result, a significantly increased complexity was found in both parietal and frontal regions of MDD patients. This significantly increased complexity was observed not only in full-band activity but also in beta and gamma sub-bands of EEG. The findings of the present study indicate the possibility of using the wavelet-chaos methodology to discriminate the EEGs of MDD patients from healthy controls. PMID:26738004

  8. EEG signal features extraction based on fractal dimension.

    PubMed

    Finotello, Francesca; Scarpa, Fabio; Zanon, Mattia

    2015-08-01

    The spread of electroencephalography (EEG) in countless applications has fostered the development of new techniques for extracting synthetic and informative features from EEG signals. However, the definition of an effective feature set depends on the specific problem to be addressed and is currently an active field of research. In this work, we investigated the application of features based on fractal dimension to a problem of sleep identification from EEG data. We demonstrated that features based on fractal dimension, including two novel indices defined in this work, add valuable information to standard EEG features and significantly improve sleep identification performance. PMID:26737209

  9. Non-invasive EEG evaluation in epilepsy diagnosis.

    PubMed

    Rosenow, Felix; Klein, Karl Martin; Hamer, Hajo M

    2015-04-01

    The EEG is an invaluable tool in the diagnosis of epilepsy which guides clinical management. It helps to determine if attacks are of epileptic origin, allows the estimation of the recurrence risk after a first seizure, aids in the diagnosis of the epilepsy syndrome and represents the gold standard in the presurgical evaluation of epilepsy. The EEG can also detect subclinical seizures as a cause of coma. In this review we discuss the sensitivity and specificity of the EEG, present the EEG findings and their significance in different epilepsy syndromes including focal and generalized epilepsies and describe the application of activation procedures. PMID:25779862

  10. Synchronization of EEG activity in patients with bipolar disorder

    NASA Astrophysics Data System (ADS)

    Panischev, O. Yu; Demin, S. A.; Muhametshin, I. G.; Demina, N. Yu

    2015-12-01

    In paper we apply the method based on the Flicker-Noise Spectroscopy (FNS) to determine the differences in frequency-phase synchronization of the cortical electroencephalographic (EEG) activities in patients with bipolar disorder (BD). We found that for healthy subjects the frequency-phase synchronization of EEGs from long-range electrodes was significantly better for BD patients. In BD patients a high synchronization of EEGs was observed only for short-range electrodes. Thus, the FNS is a simple graphical method for qualitative analysis can be applied to identify the synchronization effects in EEG activity and, probably, may be used for the diagnosis of this syndrome.

  11. The qEEG Signature of Selective NMDA NR2B Negative Allosteric Modulators; A Potential Translational Biomarker for Drug Development

    PubMed Central

    Keavy, Deborah; Bristow, Linda J.; Sivarao, Digavalli V.; Batchelder, Margaret; King, Dalton; Thangathirupathy, Srinivasan; Macor, John E.; Weed, Michael R.

    2016-01-01

    The antidepressant activity of the N-methyl-D-aspartate (NMDA) receptor channel blocker, ketamine, has led to the investigation of negative allosteric modulators (NAMs) selective for the NR2B receptor subtype. The clinical development of NR2B NAMs would benefit from a translational pharmacodynamic biomarker that demonstrates brain penetration and functional inhibition of NR2B receptors in preclinical species and humans. Quantitative electroencephalography (qEEG) is a translational measure that can be used to demonstrate pharmacodynamic effects across species. NMDA receptor channel blockers, such as ketamine and phencyclidine, increase the EEG gamma power band, which has been used as a pharmacodynamic biomarker in the development of NMDA receptor antagonists. However, detailed qEEG studies with ketamine or NR2B NAMs are lacking in nonhuman primates. The aim of the present study was to determine the effects on the qEEG power spectra of the NR2B NAMs traxoprodil (CP-101,606) and BMT-108908 in nonhuman primates, and to compare them to the NMDA receptor channel blockers, ketamine and lanicemine. Cynomolgus monkeys were surgically implanted with EEG radio-telemetry transmitters, and qEEG was measured after vehicle or drug administration. The relative power for a number of frequency bands was determined. Ketamine and lanicemine increased relative gamma power, whereas the NR2B NAMs traxoprodil and BMT-108908 had no effect. Robust decreases in beta power were elicited by ketamine, traxoprodil and BMT-108908; and these agents also produced decreases in alpha power and increases in delta power at the doses tested. These results suggest that measurement of power spectra in the beta and delta bands may represent a translational pharmacodynamic biomarker to demonstrate functional effects of NR2B NAMs. The results of these studies may help guide the selection of qEEG measures that can be incorporated into early clinical evaluation of NR2B NAMs in healthy humans. PMID:27035340

  12. How to write an EEG report: dos and don'ts.

    PubMed

    Kaplan, Peter W; Benbadis, Selim R

    2013-01-01

    The EEG report is structured to include demographics of the patient studied and reason for the EEG; specifics of the EEG techniques used; a description of the patterns, frequencies, voltages, and progression of the EEG pattern that were recorded; and finally a clinical impression of the EEG significance. The interpretation should be concise, clear and to the point, avoid jargon and EEG specifics, and should be understandable by any health care practitioner. PMID:23267044

  13. [Central EEG rhythm associated with movement and EEG rhythm associated with spatial reasoning: are they homologous?].

    PubMed

    Tarotin, I V; Ivanitsky, G A

    2014-01-01

    EEG rhythmical picture of subject's movement suppression and spatial-figurative task solving was examined and analyzed. Rhythms appearing during spatial reasoning and suppressed movements with the frequency of about 11 Hz were isolated. It was hypothesized that a functional link exists between these rhythms in the considered behavioral tests. To test the hypothesis and to reveal this connection, experiments were developed and carried out. Then the analysis of recorded EEG signals was conducted by applying Fourier transform, independent component analysis (ICA) and equivalent dipole source localization. Unexpected conclusion about the existence of a general mechanism of movement suppression was drawn. PMID:25975138

  14. Alpha globin gene analysis in a Sardinian family with interacting alpha and beta thalassaemia genes.

    PubMed

    Melis, M A; Galanello, R; Cao, A

    1983-04-01

    This paper reports the results of alpha globin gene analysis in a Sardinian family with interacting alpha and beta thalassaemia genes. The propositus, who was identified in a newborn survey as he had 26.0% Hb Bart's and 74.0% Hb F, successively developed the clinical and haematological picture of a transfusion-dependent thalassaemia major. According to the haemoglobin pattern, restriction endonuclease analysis of the DNA from this patient showed the deletion of three of the four alpha-globin structural genes. Thus beta 0-thalassaemia homozygotes with the delection of three alpha-structural genes seem to have a severe clinical phenotype similar to that of patients with a full complement of four alpha-globin structural genes. PMID:6299325

  15. Resting-state EEG study of comatose patients: a connectivity and frequency analysis to find differences between vegetative and minimally conscious states

    PubMed Central

    Lehembre, Rémy; Bruno, Marie-Aurélie; Vanhaudenhuyse, Audrey; Chatelle, Camille; Cologan, Victor; Leclercq, Yves; Soddu, Andrea; Macq, Benoît; Laureys, Steven; Noirhomme, Quentin

    2012-01-01

    Summary The aim of this study was to look for differences in the power spectra and in EEG connectivity measures between patients in the vegetative state (VS/UWS) and patients in the minimally conscious state (MCS). The EEG of 31 patients was recorded and analyzed. Power spectra were obtained using modern multitaper methods. Three connectivity measures (coherence, the imaginary part of coherency and the phase lag index) were computed. Of the 31 patients, 21 were diagnosed as MCS and 10 as VS/UWS using the Coma Recovery Scale-Revised (CRS-R). EEG power spectra revealed differences between the two conditions. The VS/UWS patients showed increased delta power but decreased alpha power compared with the MCS patients. Connectivity measures were correlated with the CRS-R diagnosis; patients in the VS/UWS had significantly lower connectivity than MCS patients in the theta and alpha bands. Standard EEG recorded in clinical conditions could be used as a tool to help the clinician in the diagnosis of disorders of consciousness. PMID:22687166

  16. Pattern changes of EEG oscillations and BOLD signals associated with temporal lobe epilepsy as revealed by a working memory task

    PubMed Central

    2014-01-01

    Background It is known that the abnormal neural activity in epilepsy may be associated to the reorganization of neural circuits and brain plasticity in various ways. On that basis, we hypothesized that changes in neuronal circuitry due to epilepsy could lead to measurable variations in patterns of both EEG and BOLD signals in patients performing some cognitive task as compared to what would be obtained in normal condition. Thus, the aim of this study was to compare the cerebral areas involved in EEG oscillations versus fMRI signal patterns during a working memory (WM) task in normal controls and patients with refractory mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS). The study included six patients with left MTLE-HS (left-HS group) and seven normal controls (control group) matched to the patients by age and educational level, both groups undergoing a blocked design paradigm based on Sternberg test during separated EEG and fMRI sessions. This test consisted of encoding and maintenance of a variable number of consonant letters on WM. Results EEG analysis for the encoding period revealed the presence of theta and alpha oscillations in the frontal and parietal areas, respectively. Likewise, fMRI showed the co-occurrence of positive and negative BOLD signals in both brain regions. As for the maintenance period, whereas EEG analysis revealed disappearance of theta oscillation, fMRI showed decrease of positive BOLD in frontal area and increase of negative BOLD in the posterior part of the brain. Conclusions Generally speaking, these patterns of electrophysiological and hemodynamic signals were observed for both control and left-HS groups. However, the data also revealed remarkable differences between these groups that are consistent with the hypothesis of reorganization of brain circuitry associated with epilepsy. PMID:24766708

  17. The EEG and fMRI signatures of neural integration: An investigation of meaningful gestures and corresponding speech.

    PubMed

    He, Yifei; Gebhardt, Helge; Steines, Miriam; Sammer, Gebhard; Kircher, Tilo; Nagels, Arne; Straube, Benjamin

    2015-06-01

    One of the key features of human interpersonal communication is our ability to integrate information communicated by speech and accompanying gestures. However, it is still not fully understood how this essential combinatory process is represented in the human brain. Functional magnetic resonance imaging (fMRI) studies have unanimously attested the relevance of activation in the posterior superior temporal sulcus/middle temporal gyrus (pSTS/MTG), while electroencephalography (EEG) studies have shown oscillatory activity in specific frequency bands to be associated with multisensory integration. In the current study, we used fMRI and EEG to separately investigate the anatomical and oscillatory neural signature of integrating intrinsically meaningful gestures (IMG; e.g. "Thumbs-up gesture") and corresponding speech (e.g., "The actor did a good job"). In both the fMRI (n =2 0) and EEG (n = 20) study, participants were presented with videos of an actor either: performing IMG in the context of a German sentence (GG), IMG in the context of a Russian (as a foreign language) sentence (GR), or speaking an isolated German sentence without gesture (SG). The results of the fMRI experiment confirmed that gesture-speech processing of IMG activates the posterior MTG (GG>GR∩GG>SG). In the EEG experiment we found that the identical integration process (GG>GR∩GG>SG) is related to a centrally-distributed alpha (7-13 Hz) power decrease within 700-1400 ms post-onset of the critical word. These new findings suggest that BOLD response increase in the pMTG and alpha power decrease represent the neural correlates of integrating intrinsically meaningful gestures with their corresponding speech. PMID:25900470

  18. Standardized Computer-based Organized Reporting of EEG: SCORE

    PubMed Central

    Beniczky, Sándor; Aurlien, Harald; Brøgger, Jan C; Fuglsang-Frederiksen, Anders; Martins-da-Silva, António; Trinka, Eugen; Visser, Gerhard; Rubboli, Guido; Hjalgrim, Helle; Stefan, Hermann; Rosén, Ingmar; Zarubova, Jana; Dobesberger, Judith; Alving, Jørgen; Andersen, Kjeld V; Fabricius, Martin; Atkins, Mary D; Neufeld, Miri; Plouin, Perrine; Marusic, Petr; Pressler, Ronit; Mameniskiene, Ruta; Hopfengärtner, Rüdiger; Emde Boas, Walter; Wolf, Peter

    2013-01-01

    The electroencephalography (EEG) signal has a high complexity, and the process of extracting clinically relevant features is achieved by visual analysis of the recordings. The interobserver agreement in EEG interpretation is only moderate. This is partly due to the method of reporting the findings in free-text format. The purpose of our endeavor was to create a computer-based system for EEG assessment and reporting, where the physicians would construct the reports by choosing from predefined elements for each relevant EEG feature, as well as the clinical phenomena (for video-EEG recordings). A working group of EEG experts took part in consensus workshops in Dianalund, Denmark, in 2010 and 2011. The faculty was approved by the Commission on European Affairs of the International League Against Epilepsy (ILAE). The working group produced a consensus proposal that went through a pan-European review process, organized by the European Chapter of the International Federation of Clinical Neurophysiology. The Standardised Computer-based Organised Reporting of EEG (SCORE) software was constructed based on the terms and features of the consensus statement and it was tested in the clinical practice. The main elements of SCORE are the following: personal data of the patient, referral data, recording conditions, modulators, background activity, drowsiness and sleep, interictal findings, “episodes” (clinical or subclinical events), physiologic patterns, patterns of uncertain significance, artifacts, polygraphic channels, and diagnostic significance. The following specific aspects of the neonatal EEGs are scored: alertness, temporal organization, and spatial organization. For each EEG finding, relevant features are scored using predefined terms. Definitions are provided for all EEG terms and features. SCORE can potentially improve the quality of EEG assessment and reporting; it will help incorporate the results of computer-assisted analysis into the report, it will make

  19. Emergence of synchronous EEG spindles from asynchronous MEG spindles.

    PubMed

    Dehghani, Nima; Cash, Sydney S; Halgren, Eric

    2011-12-01

    Sleep spindles are bursts of rhythmic 10-15 Hz activity, lasting ∼0.5-2 s, that occur during Stage 2 sleep. They are coherent across multiple cortical and thalamic locations in animals, and across scalp EEG sites in humans, suggesting simultaneous generation across the cortical mantle. However, reports of MEG spindles occurring without EEG spindles, and vice versa, are inconsistent with synchronous distributed generation. We objectively determined the frequency of MEG-only, EEG-only, and combined MEG-EEG spindles in high density recordings of natural sleep in humans. About 50% of MEG spindles occur without EEG spindles, but the converse is rare (∼15%). Compared to spindles that occur in MEG only, those that occur in both MEG and EEG have ∼1% more MEG coherence and ∼15% more MEG power, insufficient to account for the ∼55% increase in EEG power. However, these combined spindles involve ∼66% more MEG channels, especially over frontocentral cortex. Furthermore, when both MEG and EEG are involved in a given spindle, the MEG spindle begins ∼150 ms before the EEG spindle and ends ∼250 ms after. Our findings suggest that spindles begin in focal cortical locations which are better recorded with MEG gradiometers than referential EEG due to the biophysics of their propagation. For some spindles, only these regions remain active. For other spindles, these locations may recruit other areas over the next 200 ms, until a critical mass is achieved, including especially frontal cortex, resulting in activation of a diffuse and/or multifocal generator that is best recorded by referential EEG derivations due to their larger leadfields. PMID:21337472

  20. Object-based attentional selection modulates anticipatory alpha oscillations.

    PubMed

    Knakker, Balázs; Weiss, Béla; Vidnyánszky, Zoltán

    2014-01-01

    Visual cortical alpha oscillations are involved in attentional gating of incoming visual information. It has been shown that spatial and feature-based attentional selection result in increased alpha oscillations over the cortical regions representing sensory input originating from the unattended visual field and task-irrelevant visual features, respectively. However, whether attentional gating in the case of object based selection is also associated with alpha oscillations has not been investigated before. Here we measured anticipatory electroencephalography (EEG) alpha oscillations while participants were cued to attend to foveal face or word stimuli, the processing of which is known to have right and left hemispheric lateralization, respectively. The results revealed that in the case of simultaneously displayed, overlapping face and word stimuli, attending to the words led to increased power of parieto-occipital alpha oscillations over the right hemisphere as compared to when faces were attended. This object category-specific modulation of the hemispheric lateralization of anticipatory alpha oscillations was maintained during sustained attentional selection of sequentially presented face and word stimuli. These results imply that in the case of object-based attentional selection-similarly to spatial and feature-based attention-gating of visual information processing might involve visual cortical alpha oscillations. PMID:25628554

  1. Perception-related EEG is more sensitive to Alzheimer's disease effects than resting EEG.

    PubMed

    Barzegaran, Elham; van Damme, Bart; Meuli, Reto; Knyazeva, Maria G

    2016-07-01

    To characterize the effects of Alzheimer's disease (AD) on cortical functional connectivity in perception, we analyzed interhemispheric lagged synchronization (ILS) in the source space of high-density EEG recorded in aged controls and patients with amnestic mild cognitive impairment (aMCI) or AD while they viewed collinear and noncollinear bilateral moving gratings. Beta-band ILS was lower in aMCI and AD compared with controls in a large region centered on BA39. As previously reported, in young adults, collinear iso-oriented gratings versus noncollinear gratings synchronizes EEG reflecting perceptual grouping. Only aged controls showed the expected beta-band ILS increase originating in the dorsal visual stream (BA18). The aMCI group only showed a theta-band increase in an adjacent region (BA19). In AD patients, there was no ILS increase. Regression analysis revealed that the posterior callosal area and EEG slowing predict reduction of beta but not emergence of theta ILS response. Considering that we found no between-group differences in resting ILS, perception-related EEG appears to be more sensitive to AD effects, including ILS signs of neurodegeneration and compensation. PMID:27255822

  2. EEG Oscillation Evidences of Enhanced Susceptibility to Emotional Stimuli during Adolescence

    PubMed Central

    Meng, Xianxin; Liu, Wenwen; Zhang, Ling; Li, Xiang; Yao, Bo; Ding, Xinsheng; Yuan, JiaJin; Yang, Jiemin

    2016-01-01

    Background: Our recent event-related potential (ERP) study showed that adolescents are more emotionally sensitive to negative events compared to adults, regardless of the valence strength of the events. The current work aimed to confirm this age-related difference in response to emotional stimuli of diverse intensities by examining Electroencephalography (EEG) oscillatory power in time-frequency analysis. Methods: Time-frequency analyses were performed on the EEG data recorded for highly negative (HN), moderately negative (MN) and Neutral pictures in 20 adolescents and 20 adults during a covert emotional task. The results showed a significant age by emotion interaction effect in the theta and beta oscillatory power during the 500–600 ms post stimulus. Results: Adolescents showed significantly less pronounced theta synchronization (ERS, 5.5–7.5 Hz) for HN stimuli, and larger beta desynchronization (ERD; 18–20 Hz) for both HN and MN stimuli, in comparison with neutral stimuli. By contrast, adults exhibited no significant emotion effects in theta and beta frequency bands. In addition, the analysis of the alpha spectral power (10.5–12 Hz; 850–950 ms) showed a main effect of emotion, while the emotion by age interaction was not significant. Irrespective of adolescents or adults, HN and MN stimuli elicited enhanced alpha suppression compared to Neutral stimuli, while the alpha power was similar across HN and MN conditions. Conclusions: These results confirmed prior findings that adolescents are more sensitive to emotionally negative stimuli compared to adults, regardless of emotion intensity, possibly due to the developing prefrontal control system during adolescence. PMID:27242568

  3. Usefulness of video-EEG in the paediatric emergency department.

    PubMed

    Falsaperla, Raffaele; Striano, Pasquale; Parisi, Pasquale; Lubrano, Riccardo; Mahmood, Fahad; Pavone, Piero; Vitaliti, Giovanna

    2014-07-01

    Over the past two decades the EEG has technically improved from the use of analog to digital machines and more recently to video-EEG systems. Despite these advances, recording a technically acceptable EEG in an electrically hostile environment such as the emergency department (ED) remains a challenge, particularly with infants or young children. In 1996, a meeting of French experts established a set of guidelines for performing an EEG in the ED based on a review of the available literature. The authors highlighted the most suitable indications for an emergency EEG including clinical suspicion of cerebral death, convulsive and myoclonic status epilepticus, focal or generalized relapsing convulsive seizures as well as follow-up of known convulsive patients. They further recommended emergency EEG in the presence of doubt regarding the epileptic nature of the presentation as well as during the initiation or modification of sedation following brain injury. Subsequently, proposals for expanding the use of EEG in emergency patients have been advocated including trauma, vascular and anoxic-ischemic injury due to cardiorespiratory arrest, postinfective encephalopathy and nonconvulsive status epilepticus. The aim of this review is to show the diagnostic importance of video-EEG, as well as highlighting the predictive prognostic factors for positive and negative outcomes, when utilized in the pediatric ED for seizures as well as other neurological presentations. PMID:24917085

  4. EEG Markers for Attention Deficit Disorder: Pharmacological and Neurofeedback Applications.

    ERIC Educational Resources Information Center

    Sterman, M. Barry

    2000-01-01

    Examined contribution of EEG findings in the classification and treatment of attention deficit and related behavioral problems in children. Found that quantitative EEG methods disclosed patterns of abnormality in children with ADD, suggested improved guidelines for pharmacological treatment, and introduced neurofeedback, a behavioral treatment for…

  5. Fuzzy similarity index for discrimination of EEG signals.

    PubMed

    Ubeyli, Elif Derya

    2006-01-01

    In this study, a new approach based on the computation of fuzzy similarity index was presented for discrimination of electroencephalogram (EEG) signals. The EEG, a highly complex signal, is one of the most common sources of information used to study brain function and neurological disorders. The analyzed EEG signals were consisted of five sets (set A-healthy volunteer, eyes open; set B-healthy volunteer, eyes closed; set C-seizure-free intervals of five patients from hippocampal formation of opposite hemisphere; set D-seizure-free intervals of five patients from epileptogenic zone; set E-epileptic seizure segments). The EEG signals were considered as chaotic signals and this consideration was tested successfully by the computation of Lyapunov exponents. The computed Lyapunov exponents were used to represent the EEG signals. The aim of the study is discriminating the EEG signals by the combination of Lyapunov exponents and fuzzy similarity index. Toward achieving this aim, fuzzy sets were obtained from the feature sets (Lyapunov exponents) of the signals under study. The results demonstrated that the similarity between the fuzzy sets of the studied signals indicated the variabilities in the EEG signals. Thus, the fuzzy similarity index could discriminate the healthy EEG segments (sets A and B) and the other three types of segments (sets C, D, and E) recorded from epileptic patients. PMID:17945895

  6. Using EEG to Study Cognitive Development: Issues and Practices

    ERIC Educational Resources Information Center

    Bell, Martha Ann; Cuevas, Kimberly

    2012-01-01

    Developmental research is enhanced by use of multiple methodologies for examining psychological processes. The electroencephalogram (EEG) is an efficient and relatively inexpensive method for the study of developmental changes in brain-behavior relations. In this review, we highlight some of the challenges for using EEG in cognitive development…

  7. Effects of Fipronil on the EEG of Long Evans Rats

    EPA Science Inventory

    We have reported that the non-stimulus driven EEG is differentially altered by deltamethrin or permethrin (Lyke and Herr, Toxicologist, 114(S-1):265, 2010). In the current study, we examined the ability to detect changes in EEG activity produced by fipronil, a phenylpyrazole pest...

  8. Wireless recording systems: from noninvasive EEG-NIRS to invasive EEG devices.

    PubMed

    Sawan, Mohamad; Salam, Muhammad T; Le Lan, Jérôme; Kassab, Amal; Gelinas, Sébastien; Vannasing, Phetsamone; Lesage, Frédéric; Lassonde, Maryse; Nguyen, Dang K

    2013-04-01

    In this paper, we present the design and implementation of a wireless wearable electronic system dedicated to remote data recording for brain monitoring. The reported wireless recording system is used for a) simultaneous near-infrared spectrometry (NIRS) and scalp electro-encephalography (EEG) for noninvasive monitoring and b) intracerebral EEG (icEEG) for invasive monitoring. Bluetooth and dual radio links were introduced for these recordings. The Bluetooth-based device was embedded in a noninvasive multichannel EEG-NIRS system for easy portability and long-term monitoring. On the other hand, the 32-channel implantable recording device offers 24-bit resolution, tunable features, and a sampling frequency up to 2 kHz per channel. The analog front-end preamplifier presents low input-referred noise of 5 μ VRMS and a signal-to-noise ratio of 112 dB. The communication link is implemented using a dual-band radio frequency transceiver offering a half-duplex 800 kb/s data rate, 16.5 mW power consumption and less than 10(-10) post-correction Bit-Error Rate (BER). The designed system can be accessed and controlled by a computer with a user-friendly graphical interface. The proposed wireless implantable recording device was tested in vitro using real icEEG signals from two patients with refractory epilepsy. The wirelessly recorded signals were compared to the original signals recorded using wired-connection, and measured normalized root-mean square deviation was under 2%. PMID:23853301

  9. Pulse artifact detection in simultaneous EEG-fMRI recording based on EEG map topography.

    PubMed

    Iannotti, Giannina R; Pittau, Francesca; Michel, Christoph M; Vulliemoz, Serge; Grouiller, Frédéric

    2015-01-01

    One of the major artifact corrupting electroencephalogram (EEG) acquired during functional magnetic resonance imaging (fMRI) is the pulse artifact (PA). It is mainly due to the motion of the head and attached electrodes and wires in the magnetic field occurring after each heartbeat. In this study we propose a novel method to improve PA detection by considering the strong gradient and inversed polarity between left and right EEG electrodes. We acquired high-density EEG-fMRI (256 electrodes) with simultaneous electrocardiogram (ECG) at 3 T. PA was estimated as the voltage difference between right and left signals from the electrodes showing the strongest artifact (facial and temporal). Peaks were detected on this estimated signal and compared to the peaks in the ECG recording. We analyzed data from eleven healthy subjects, two epileptic patients and four healthy subjects with an insulating layer between electrodes and scalp. The accuracy of the two methods was assessed with three criteria: (i) standard deviation, (ii) kurtosis and (iii) confinement into the physiological range of the inter-peak intervals. We also checked whether the new method has an influence on the identification of epileptic spikes. Results show that estimated PA improved artifact detection in 15/17 cases, when compared to the ECG method. Moreover, epileptic spike identification was not altered by the correction. The proposed method improves the detection of pulse-related artifacts, particularly crucial when the ECG is of poor quality or cannot be recorded. It will contribute to enhance the quality of the EEG increasing the reliability of EEG-informed fMRI analysis. PMID:25307731

  10. Classification of spontaneous EEG signals in migraine

    NASA Astrophysics Data System (ADS)

    Bellotti, R.; De Carlo, F.; de Tommaso, M.; Lucente, M.

    2007-08-01

    We set up a classification system able to detect patients affected by migraine without aura, through the analysis of their spontaneous EEG patterns. First, the signals are characterized by means of wavelet-based features, than a supervised neural network is used to classify the multichannel data. For the feature extraction, scale-dependent and scale-independent methods are considered with a variety of wavelet functions. Both the approaches provide very high and almost comparable classification performances. A complete separation of the two groups is obtained when the data are plotted in the plane spanned by two suitable neural outputs.

  11. Using Bayesian Model Selection to Characterize Neonatal Eeg Recordings

    NASA Astrophysics Data System (ADS)

    Mitchell, Timothy J.

    2009-12-01

    The brains of premature infants must undergo significant maturation outside of the womb and are thus particularly susceptible to injury. Electroencephalographic (EEG) recordings are an important diagnostic tool in determining if a newborn's brain is functioning normally or if injury has occurred. However, interpreting the recordings is difficult and requires the skills of a trained electroencephelographer. Because these EEG specialists are rare, an automated interpretation of newborn EEG recordings would increase access to an important diagnostic tool for physicians. To automate this procedure, we employ Bayesian probability theory to compute the posterior probability for the EEG features of interest and use the results in a program designed to mimic EEG specialists. Specifically, we will be identifying waveforms of varying frequency and amplitude, as well as periods of flat recordings where brain activity is minimal.

  12. Multimodal emotion recognition using EEG and eye tracking data.

    PubMed

    Zheng, Wei-Long; Dong, Bo-Nan; Lu, Bao-Liang

    2014-01-01

    This paper presents a new emotion recognition method which combines electroencephalograph (EEG) signals and pupillary response collected from eye tracker. We select 15 emotional film clips of 3 categories (positive, neutral and negative). The EEG signals and eye tracking data of five participants are recorded, simultaneously, while watching these videos. We extract emotion-relevant features from EEG signal