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EEG alpha phenotypes: linkage analyses and relation to alcohol dependence in an American Indian community study  

Microsoft Academic Search

BACKGROUND: Evidence for a high degree of heritability of EEG alpha phenotypes has been demonstrated in twin and family studies in a number of populations. However, information on linkage of this phenotype to specific chromosome locations is still limited. This study's aims were to map loci linked to EEG alpha phenotypes and to determine if there was overlap with loci

Cindy L Ehlers; Ian R Gizer; Evelyn Phillips; Kirk C Wilhelmsen



Coincidence of EEG alpha Patterns in Humans.  

National Technical Information Service (NTIS)

The appearance of alpha patterns in one human may influence its appearance in another human. In selected instances, the coincidence of alpha patterns appear simultaneously in the EEG to a highly significant greater degree than would be expected by random ...

T. Behrendt T. D. Duane



EEG, alpha waves and coherence  

NASA Astrophysics Data System (ADS)

This thesis addresses some theoretical issues generated by the results of recent analysis of EEG time series proving the brain dynamics are driven by abrupt changes making them depart from the ordinary Poisson condition. These changes are renewal, unpredictable and non-ergodic. We refer to them as crucial events. How is it possible that this form of randomness be compatible with the generation of waves, for instance alpha waves, whose observation seems to suggest the opposite view the brain is characterized by surprisingly extended coherence? To shed light into this apparently irretrievable contradiction we propose a model based on a generalized form of Langevin equation under the influence of a periodic stimulus. We assume that there exist two different forms of time, a subjective form compatible with Poisson statistical physical and an objective form that is accessible to experimental observation. The transition from the former to the latter form is determined by the brain dynamics interpreted as emerging from the cooperative interaction among many units that, in the absence of cooperation would generate Poisson fluctuations. We call natural time the brain internal time and we make the assumption that in the natural time representation the time evolution of the EEG variable y(t) is determined by a Langevin equation perturbed by a periodic process that in this time representation is hardly distinguishable from an erratic process. We show that the representation of this random process in the experimental time scale is characterized by a surprisingly extended coherence. We show that this model generates a sequence of damped oscillations with a time behavior that is remarkably similar to that derived from the analysis of real EEG's. The main result of this research work is that the existence of crucial events is not incompatible with the alpha wave coherence. In addition to this important result, we find another result that may help our group, or any other research group working on the analysis of brain's dynamics, to prove or to disprove the existence of crucial events. We study the diffusion process generated by fluctuations emerging from the same model after filtering out the alpha coherence, and we study the recursion to the origin. We study the survival probability of this process, namely the probability that up to a given time no re-crossing of the origin occurs. We find that this is an inverse power law with a power that depends on whether or not crucial events exist.

Ascolani, Gianluca



PubMed Central

Nearly all research in neurofeedback since the 1960s has focused on training voluntary control over EEG constructs. By contrast, EEG state discrimination training focuses on awareness of subjective correlates of EEG states. This study presents the first successful replication of EEG alpha state discrimination first reported by Kamiya (1962). A 150-second baseline was recorded in 106 participants. During the task, low (<30th percentile of the baseline) and high alpha events (>70th percentile) triggered a prompt. Participants indicated “high” or “low” with a keypress response and received immediate feedback. Seventy-five percent of participants achieved significant discrimination within nine sessions, with a significant learning curve effect. Performance was significantly related to physical properties of the EEG signal, including magnitude, duration, and absolute vs. relative amplitude. These results are consistent with a conceptualization of EEG state discrimination as a sensory modality, although it is also intricately related to voluntary control of these states.

Frederick, Jon A.



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

Microsoft Academic Search

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.

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



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


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

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



EEG alpha rhythm, intention and oculomotor control.  


A replication of Wertheim's (1981) visual pursuit tracking study examined the reactivity of the posterior EEG alpha rhythm to two tracking tasks. Twelve subjects visually tracked a light spot moving in a predictable or an unpredictable path. The EEG was recorded from O1, O2, P3, P4, T5, and T6, referenced to linked mastoids, and power for the alpha frequency band was calculated for 60 s trial epochs. Results showed significantly higher occipital and posterior temporal alpha power during the predictable tracking trials in agreement with Wertheim's findings. The significance of this for his attention/intention model is discussed. PMID:10489080

Loze, G M; Collins, D; Shaw, J C



Simultaneous EEG and fMRI of the alpha rhythm  

Microsoft Academic Search

The alpha rhythm in the EEG is 8-12 Hz activity present when a subject is awake with eyes closed. In this study, we used simultaneous EEG and fMRI to make maps of regions whose MRI signal changed reliably with modulation in posterior alpha activity. We scanned 11 subjects as they rested with eyes closed. We found that increased alpha power

Robin I. Goldman; John M. Stern; Jerome Engel Jr; Mark S. Cohen; Jr. J. Engel



Linkage and linkage disequilibrium mapping of ERP and EEG phenotypes  

Microsoft Academic Search

Linkage analyses of highly heritable electrophysiological phenotypes (EEG, ERP) that can potentially identify individuals at risk for alcoholism were performed on a large sample of families with a high density of alcohol dependence as part of the Collaborative Study on the Genetics of Alcoholism (COGA); these genetic findings are summarized. Quantitative trait loci (QTLs) were identified for several ERP characteristics

Bernice Porjesz; Henri Begleiter; Kongming Wang; Laura Almasy; D avid B. Chorlian; Arthur T. Stimus; Samuel Kuperman; Sean J. O'Connor; John Rohrbaugh; Lance O. Bauer; Howard J. Edenberg; Alison Goate; John P. Rice; Theodore Reich



Volunteers with high versus low alpha EEG have different pain–EEG relationship: a human experimental study  

Microsoft Academic Search

The alpha rhythm (7.5–12 Hz) is one of the fundamental features of the human EEG which usually has maximum amplitude over\\u000a occipital regions. It is well recognized that individuals have highly different magnitudes of alpha EEG. This study examined\\u000a occipital alpha EEG activity during different levels of experimental tonic cuff-pressure pain. The aim was to study the pain\\u000a reactions and pain–EEG

Line Lindhardt Egsgaard; Li Wang; Lars Arendt-Nielsen



The Locus of Control Construct in EEG Alpha Rhythm Feedback  

ERIC Educational Resources Information Center

The present study investigated locus of control, and performance in a biofeedback situation where the goal was to increase EEG alpha rhythm. Subjects with an internal locus of control were better able to use feedback to increase their alpha activity than external subjects. (Author)

Johnson, Richard K.; Meyer, Robert G.



Developing a biofeedback model: Alpha eeg feedback as a means for pain control  

Microsoft Academic Search

3 adept meditators voluntarily inserted steel needles into their bodies while physiological measures (EEG, EMG, GSR, EKG, and respiratbn)were recorded. Although each adept used a different passive attention technique, none reported pain. During the insertion, 2 of the 3 Ss increased their alpha EEG activity. The role of alpha EEG and its relationship to pain control is discussed.

Kenneth R. Pelletier; Erik Peper



Alpha 1 antitrypsin phenotypes and alcoholic pancreatitis.  

PubMed Central

Altered frequencies of alpha 1 antitrypsin phenotypes have been reported in patients with chronic pancreatitis, suggesting a possible genetic basis for individual susceptibility to this disease. Alpha 1 antitrypsin phenotypes, with particular regard to alcoholic pancreatitis, were studied. Patients with alcoholic pancreatitis were compared with alcoholic control subjects with no history of pancreatic disease. Serum alpha 1 antitrypsin concentrations were raised in pancreatitis patients sampled within one month of an acute attack of pancreatitis, but otherwise values were similar to those of control subjects. There were no significant differences in alpha 1 antitrypsin phenotypes between alcoholics with pancreatitis and alcoholic control subjects. This study of alpha 1 antitrypsin phenotypes provides no evidence of an inherited susceptibility to alcoholic pancreatitis.

Haber, P S; Wilson, J S; McGarity, B H; Hall, W; Thomas, M C; Pirola, R C



EEG alpha and theta oscillations reflect cognitive and memory performance: a review and analysis  

Microsoft Academic Search

Evidence is presented that EEG oscillations in the alpha and theta band reflect cognitive and memory performance in particular. Good performance is related to two types of EEG phenomena (i) a tonic increase in alpha but a decrease in theta power, and (ii) a large phasic (event-related) decrease in alpha but increase in theta, depending on the type of memory

Wolfgang Klimesch



Finding thalamic BOLD correlates to posterior alpha EEG.  


Oscillatory electrical brain activity in the alpha (8-13 Hz) band is a prominent feature of human electroencephalography (EEG) during alert wakefulness, and is commonly thought to arise primarily from the occipital and parietal parts of the cortex. While the thalamus is considered to play a supportive role in the generation and modulation of cortical alpha rhythms, its precise function remains controversial and incompletely understood. To address this, we evaluated the correlation between the blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals in the thalamus and the spontaneous modulation of posterior alpha rhythms based on EEG-fMRI data acquired concurrently during an eyes-closed task-free condition. We observed both negative and positive correlations in the thalamus. The negative correlations were mostly seen within the visual thalamus, with a preference for the pulvinar over lateral geniculate nuclei. The positive correlations were found at the anterior and medial dorsal nuclei. Through functional connectivity analysis of the fMRI data, the pulvinar was found to be functionally associated with the same widespread cortical visual areas where the fMRI signals were negatively correlated with the posterior alpha modulation. In contrast, the dorsal nuclei were part of a distinct functional network that included brain stem, cingulate cortex and cerebellum. These observations are consistent with previous animal electrophysiology studies and the notion that the visual thalamus, and the pulvinar in particular, is intimately involved in the generation and spontaneous modulation of posterior alpha rhythms, facilitated by its reciprocal and widespread interaction with the cortical visual areas. We further postulate that the anterior and medial dorsal nuclei, being part of the ascending neuromodulatory system, may indirectly modulate cortical alpha rhythms by affecting vigilance and arousal levels. PMID:22986355

Liu, Zhongming; de Zwart, Jacco A; Yao, Bing; van Gelderen, Peter; Kuo, Li-Wei; Duyn, Jeff H



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

ERIC Educational Resources Information Center

|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…

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




PubMed Central

The aim of this study was to evaluate the correlation between psychopathological dimensions in recent-onset neuroleptic-naive schizophrenic patients and EEG alpha coherence in the resting state. 37 neuroleptic-naive recent-onset schizophrenic patients were assessed on the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms, and psychopathological dimension scores on reality distortion, psychomotor poverty and disorganization were calculated. EEG alpha coherence was computed across 14 intra-hemispheric and 8 interhemispheric electrode pairs in the resting eyes closed and eyes open conditions. The relationship between the psychopathological dimension scores and coherence values was assessed using Pearson's product moment correlation with Bonferroni correction for levels of significance. Significant associations between higher psychomotor poverty scores and lower inter-hemispheric coherence values were found across the central and parietal regions in the eyes closed condition and across central regions in the eyes open condition. Reality distortion and disorganization dimensions were not significantly correlated with intra- or inter-hemispheric coherences in both eyes closed and eyes open conditions. However there was a trend for an inverse correlation between disorganization dimension and intra-hemispheric coherence across left frontal, left temporo-parietal and right parieto-occipital regions in the eyes open condition. These findings suggest a possible differential pattern in the extent of brain involvement across the three psychopathological dimensions of schizophrenia in neurolepticnaive patients with recent-onset illness.

John, John P.; Khanna, Sumant; Pradhan, N.; Mukundan, C.R.



Power density in theta/alpha frequencies of the waking EEG progressively increases during sustained wakefulness.  


Electroencephalogram (EEG) power density and self-rated fatigue were assessed in nine healthy women during a 40-hour period of sustained wakefulness under constant behavioral and environmental conditions (constant routine protocol). Waking EEG recordings were performed for 4 minutes after 3, 10, 27 and 34 hours of prior wakefulness. EEG power density in the 6.25- to 9.0-Hz frequency range progressively increased across the four recordings, suggesting an endogenous homeostatic component in the regulation of the theta/alpha frequencies under constant conditions. Subjective fatigue also exhibited an increasing component in the course of the constant routine protocol, with a clear circadian modulation. Fatigue ratings and the theta/ alpha power density of the waking EEG recorded at the same four time points during the constant routine protocol correlated significantly. Our data demonstrate the presence of a homeostatic component in the control of EEG power density in the 6.25- to 9.0-Hz range. PMID:8746397

Cajochen, C; Brunner, D P; Kräuchi, K; Graw, P; Wirz-Justice, A



EEG rhythm of alpha frequency in a 22-month-old child after strangulation.  


A 22-month-old child suffered accidental strangulation, which rendered him comatose with intermittent generalized tonic-clonic seizures. His elecroencephalogram (EEG) displayed widespread activity of alpha frequency unreactive to sensory stimuli. Upon clinical recovery, a slower posterior EEG rhythm, attenuated by eye opening, was detected, which was more consistent with the patient's age. This observation is remarkable, because of the rarity of reports of an alpha pattern after cerebral anoxia in young children and the subsequent EEG and clinical evolutions. PMID:6450333

Collins, A T; Chatrian, G E



Spatial correspondence of brain alpha activity component in fMRI and EEG  

NASA Astrophysics Data System (ADS)

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.

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



[Alpha band coherence analysis of EEG in healthy adult's and Alzheimer's type dementia patients].  


We studied the occipital inter-hemispheric coherence (IHCoh) of EEG (electrodes O1-O2) for alpha band (alpha1 - 8,0 to 10,0 Hz and alpha2 - 10,1 to 12,5 Hz) in healthy adults and Alzheimer's type dementia (ATD) subjects, to observe if there is any significant difference between these two groups that could help in the early diagnosis of ATD. We found a decrease of occipital IHCoh in ATD group for both alpha sub-bands. We believe that Coh analysis of EEG is a powerful auxiliary method in ATD diagnosis. PMID:10849626

Anghinah, R; Kanda, P A; Jorge, M S; Lima, E E; Pascuzzi, L; Melo, A C



Neuronal generators of posterior EEG alpha reflect individual differences in prioritizing personal spirituality.  


Prominent posterior EEG alpha is associated with depression and clinical response to antidepressants. Given that religious belief was protective against depression in a longitudinal study of familial risk, we hypothesized that individuals who differed by strength of spiritual beliefs might also differ in EEG alpha. Clinical evaluations and self-reports of the importance of religion or spirituality (R/S) were obtained from 52 participants, and again at 10-y followup when EEG was measured. EEG alpha was quantified using frequency PCA of current source densities (CSD-fPCA). Participants who rated R/S as highly important at initial assessment showed greater alpha compared to those who did not. Those who rated R/S important in both sessions showed greater alpha than those who changed their ratings. EEG differences were particularly well-defined for participants with lifetime depression. Findings extend the view of alpha as a marker for affective processes, suggesting an association with the ontogenesis of spirituality. PMID:23998996

Tenke, C E; Kayser, J; Miller, L; Warner, V; Wickramaratne, P; Weissman, M M; Bruder, G E



A Wireless EEG Sensors System for Computer Assisted Detection of Alpha Wave in Sleep  

Microsoft Academic Search

To gain good alpha wave for diagnosing insomnia in the situation which patient feeling comfort, an EEG sensor was designed with shorter electrode wires, battery supplied and wireless transmitter, whose another usage is brain-computer interface (BCI). The result of test represents the system can get good alpha wave and reject power-line interference at all

Ji Jun; Yu MengSun; Zhou YuBin; Jin ZhangRui



A wireless EEG sensors system for computer assisted detection of alpha wave in sleep.  


To gain good alpha wave for diagnosing insomnia in the situation which patient feeling comfort, an EEG sensor was designed with shorter electrode wires, battery supplied and wireless transmitter, whose another usage is brain-computer interface (BCI). The result of test represents the system can get good alpha wave and reject power-line interference at all. PMID:17281460

Jun, Ji; Mengsun, Yu; Yubin, Zhou; Zhangrui, Jin



Thalamic metabolic rate predicts EEG alpha power in healthy control subjects but not in depressed patients  

Microsoft Academic Search

Background: EEG alpha power has been demonstrated to be inversely related to mental activity and has subsequently been used as an indirect measure of brain activation. The hypothesis that the thalamus serves as a neuronal oscillator of alpha rhythms has been supported by studies in animals, but only minimally by studies in humans.Methods: In the current study, PET-derived measures of

Kristen A. Lindgren; Christine L. Larson; Stacey M. Schaefer; Heather C. Abercrombie; Robert T. Ward; Terrence R. Oakes; James E. Holden; Scott B. Perlman; Ruth M. Benca; Richard J. Davidson



The effect of mirthfulness upon amount of discordant right-left occipital EEG alpha  

Microsoft Academic Search

A total of 68 subjects participated in two experiments that tested the effect of exposure to comedy upon amount of discordant right-left occipital EEG alpha. Data from both showed less discordant alpha in the “laughers” and more in the “nonlaughers” at the end of exposure to a filmed comedy, as contrasted by no such group difference before treatment. Experiment 2

Sven Svebak



Long-Range Correlation in alpha-Wave Predominant EEG in Human  

NASA Astrophysics Data System (ADS)

The background noise in the alpha-predominant EEG taken from eyes-open and eyes-closed neurophysiological states is studied. Scale-free characteristic is found in both cases using the wavelet approach developed by Simonsen and Nes [1]. The numerical results further show the scaling exponent during eyes-closed is consistently lower than eyes-open. We conjecture the origin of this difference is related to the temporal reconfiguration of the neural network in the brain. To further investigate the scaling structure of the EEG background noise, we extended the second order statistics to higher order moments using the EEG increment process. We found that the background fluctuation in the alpha-predominant EEG is predominantly monofractal. Preliminary results are given to support this finding and its implication in brain functioning is discussed. [1] A.H. Simonsen and O.M. Nes, Physical Review E, 58, 2779¡V2748 (1998).

Sharif, Asif; Chyan Lin, Der; Kwan, Hon; Borette, D. S.



EEG Alpha Power Modulation of fMRI Resting-State Connectivity  

PubMed Central

Abstract In the past decade, the fast and transient coupling and uncoupling of functionally related brain regions into networks has received much attention in cognitive neuroscience. Empirical tools to study network coupling include functional magnetic resonance imaging (fMRI)-based functional and/or effective connectivity, and electroencephalography (EEG)/magnetoencephalography-based measures of neuronal synchronization. Here we use simultaneously recorded EEG and fMRI to assess whether fMRI-based connectivity and frequency-specific EEG power are related. Using data collected during resting state, we studied whether posterior EEG alpha power fluctuations are correlated with connectivity within the visual network and between the visual cortex and the rest of the brain. The results show that when alpha power increases, BOLD connectivity between the primary visual cortex and occipital brain regions decreases and that the negative relation of the visual cortex with the anterior/medial thalamus decreases and the ventral–medial prefrontal cortex is reduced in strength. These effects were specific for the alpha band, and not observed in other frequency bands. The decreased connectivity within the visual system may indicate an enhanced functional inhibition during a higher alpha activity. This higher inhibition level also attenuates long-range intrinsic functional antagonism between the visual cortex and the other thalamic and cortical regions. Together, these results illustrate that power fluctuations in posterior alpha oscillations result in local and long-range neural connectivity changes.

Petersson, Karl Magnus; Kleinschmidt, Andreas; Jensen, Ole; Bastiaansen, Marcel C.M.



Restricted environmental stimulation and the enhancement of hypnotizability: Pain, EEG alpha, skin conductance and temperature responses  

Microsoft Academic Search

Restricted environmental stimulation procedures were used with 10 Ss. The Stanford Hypnotic Clinical Scale: Adult (SHCS) of Morgan and J. R. Hilgard (1975), modified to include a posthypnotic suggestion for an analgesic reaction, and pain threshold and tolerance tests were administered prior to restricted environmental stimulation technique (REST), immediately after REST, and 10–14 days later. Occipital EEG alpha, skin conductance,

Arreed F. Barabasz



A Study on EEG Alpha Wave-based Brain-Computer Interface Remote Control System  

Microsoft Academic Search

This study designs a electroencephalography or EEG alpha wave-based brain-computer interface (BCI) TV remote control system comprising BCI interface control panel, signal acquisition system, signal processing platform and interface control circuit. The specific constitution, function, mechanism and key techniques of each part are explained in detail. To test effect of the system and determine relevant parameters, we designed and conducted

Li Penghai; Wan Baikun



Is Resting Anterior EEG Alpha Asymmetry a Trait Marker for Depression?  

Microsoft Academic Search

Several lines of evidence suggest that asymmetric anterior brain activation is related to affective style, linking left hemisphere activation to positive affect and right hemisphere activation to negative affect. However, previous reports of left frontal hypoactivation in depressed patients were not confirmed in recent studies. This study evaluated additional characteristics of resting EEG alpha (8–13 Hz) asymmetry in 15 clinically

Stefan Debener; André Beauducel; Doreen Nessler; Burkhard Brocke; Hubert Heilemann; Jürgen Kayser



Sub-second “temporal attention” modulates alpha rhythms. A high-resolution EEG study  

Microsoft Academic Search

In the present high-resolution electroencephalographic (EEG) study, event-related desynchronization\\/synchronization (ERD\\/ERS) of alpha rhythms was computed during an S1–S2 paradigm, in which a visual cue (S1) predicted a SHORT (600 ms) or LONG (1400 ms) foreperiod, preceding a visual go stimulus (S2) triggering right or left finger movement. Could orienting attention to a selective point in time influence the alpha rhythms

Claudio Babiloni; Carlo Miniussisupbsu; Fabio Babiloni; Filippo Carducci; Febo Cincotti; Claudio Del Percio; Giulia Sirello; Claudia Fracassi; Anna C. Nobre; Paolo Maria Rossini



Research report Sub-second ''temporal attention'' modulates alpha rhythms. A high-resolution EEG study  

Microsoft Academic Search

In the present high-resolution electroencephalographic (EEG) study, event-related desynchronization\\/synchronization (ERD\\/ERS) of alpha rhythms was computed during an S1-S2 paradigm, in which a visual cue (S1) predicted a SHORT (600 ms) or LONG (1400 ms) foreperiod, preceding a visual go stimulus (S2) triggering right or left finger movement. Could orienting attention to a selective point in time influence the alpha rhythms

Claudio Babilonia; Carlo Miniussi; Fabio Babilonia; Filippo Carducci; Febo Cincotti; Claudio Del Percio; Giulia Sirello; Claudia Fracassi; Anna C. Nobre; Paolo Maria Rossini


[EEG alpha band coherence analysis in healthy adults: preliminary results].  


We studied the occipital inter-hemispheric coherence of Electroencephalogram (electrodes O1-O2) for alpha band (alpha1--8.0 to 10.0 Hz and alpha2--10.1 to 12.5 Hz) in two groups of healthy individuals (young adults and subjects older than 50 years-old), to assess if there is significant difference between this two age groups. No significant difference in alpha band coherences was found between these two age groups. PMID:15830070

Anghinah, Renato; Caramelli, Paulo; Takahashi, Daniel Yassumasa; Nitrini, Ricardo; Sameshima, Koichi



EEG alpha variants and alpha power in Hispanic American and white non-Hispanic American young adults with a family history of alcohol dependence.  


Results from several studies support associations among variants in electroencephalogram (EEG) alpha voltage, alcohol dependence, ethnic heritage, and a family history of alcohol dependence, although no studies have as yet been conducted in individuals of Hispanic ethnicity. Categorization of EEG, by using spectral analyses, into high-, medium-, and low-voltage alpha, as well as absolute EEG power in alpha and beta frequency ranges, was carried out for Hispanic American (n=108) and white non-Hispanic American (n=269) young adult men and women (age range, 18 to 25 years) who had a family history, but no personal history, of alcohol dependence. Eighteen percent (n=70) of the participants were categorized as having a low-voltage alpha EEG, 16% had high-voltage alpha, and 64% had medium-voltage alpha. In comparison with findings for men, women were found to have higher overall power in the low frequency alpha (7.5-9 Hz) and beta (12-20 Hz, 20-50 Hz) frequency ranges. Hispanic Americans had a lower percentage of individuals in the low-voltage alpha group (9%) and more individuals in the medium-voltage alpha group (73%) compared with findings for white non-Hispanic Americans (low-voltage alpha, 19%; medium-voltage alpha, 62%). Results of the current study confirm the presence of ethnic stratification in EEG alpha variants. PMID:15528007

Ehlers, Cindy L; Phillips, Evelyn; Schuckit, Marc A



EEG alpha rhythm, ocular activity and basal skin resistance  

Microsoft Academic Search

Most hypotheses about the origin of the occipital alpha rhythm stress the specific influence of ocular activity.\\u000a\\u000aIn this study, the influence of eye-movement frequency and extreme upward deviation of the eyeballs (enlarging the corneo-retinal potential) on occipital alpha activity and basal skin resistance is investigated. Eye-movement frequency did not significantly influence alpha activity and basal skin resistance. On the

M. N. Verbaten; J. N. R. Beaujon; W. Sjouw



Daytime melatonin administration enhances sleepiness and theta/alpha activity in the waking EEG.  


It is still controversial whether the pineal hormone melatonin can be characterized as a hypnotic. We therefore measured subjective sleepiness and waking EEG power density in the range of 0.25-20 Hz after a single dose of melatonin (5 mg). During an 8 h mini-constant routine protocol, melatonin administered in a double blind cross-over design to healthy young men at 1300 h or 1800 h increased subjective sleepiness, as rated half-hourly on three different scales (Visual Analogue Scale, Akerstedt Sleepiness Symptoms Check List, Akerstedt Sleepiness Scale) and objective fatigue as evidenced by augmented waking EEG power density in the theta/alpha range (5.25-9 Hz). The increase in subjective sleepiness reached significance 40 min and 90 min after melatonin administration (at 1300 h and 1800 h, respectively) and lasted for 3 h (at 1300 h) and 5 h (at 1800 h). The increase in the theta/alpha frequencies of the waking EEG occurred immediately after melatonin ingestion and stayed significantly higher parallel to the higher sleepiness ratings. However, the EEG changes appeared before the subjective symptoms of sleepiness became manifest. There was a significant correlation between salivary melatonin levels and the timing of increased subjective sleepiness. Melatonin had no effects on mood. PMID:8728487

Cajochen, C; Kräuchi, K; von Arx, M A; Möri, D; Graw, P; Wirz-Justice, A



Sub-second "temporal attention" modulates alpha rhythms. A high-resolution EEG study.  


In the present high-resolution electroencephalographic (EEG) study, event-related desynchronization/synchronization (ERD/ERS) of alpha rhythms was computed during an S1-S2 paradigm, in which a visual cue (S1) predicted a SHORT (600 ms) or LONG (1400 ms) foreperiod, preceding a visual go stimulus (S2) triggering right or left finger movement. Could orienting attention to a selective point in time influence the alpha rhythms as a function of the SHORT vs. LONG foreperiod? Stronger selective attentional modulations were predicted for the SHORT than LONG condition. EEG data from 54 channels were "depurated" from phase-locked visual evoked potentials and spatially enhanced by surface Laplacian estimation (i.e., final data analysis was conducted on 16 subjects having a sufficient number of artifact-free EEG single trials). Low-band alpha rhythms (about 6-10 Hz) were supposed to be related to anticipatory attentional processes, whereas high-band alpha rhythms (10-12 Hz) would indicate task-specific visuo-motor processes. Compared to the LONG condition (foreperiod), the SHORT condition induced a quicker and stronger ERS at low-band alpha rhythm (about 6-8 Hz) over midline and bilateral prefrontal, sensorimotor, and posterior parietal areas. In contrast, the concomitant high-band alpha (about 10-12 Hz) ERD/ERS showed no significant difference between the two conditions. In conclusion, temporal attention for a sub-second delay (800 ms) did modulate low-band alpha rhythm over large regions of both cortical hemispheres. PMID:15062863

Babiloni, Claudio; Miniussi, Carlo; Babiloni, Fabio; Carducci, Filippo; Cincotti, Febo; Del Percio, Claudio; Sirello, Giulia; Fracassi, Claudia; Nobre, Anna C; Rossini, Paolo Maria



Resting frontal EEG alpha-asymmetry predicts the evaluation of affective musical stimuli.  


Resting frontal electroencephalographic (EEG) alpha-asymmetry was measured in 16 participants to predict affective responses to musical stimuli. Three affective musical stimuli either expressing neutral, positive or negative mood were evaluated by the subjects concerning "expressed mood" and "level of enjoyment". The results show that individuals with relatively higher alpha power over right frontal electrode sites rated all stimuli more positive than participants with relatively higher alpha power over left frontal electrode sites. On the "expressed mood" scale, the valence of the stimuli did not influence the difference between the ratings of left- and right-active individuals. On the "enjoyment" scale, the largest difference between the ratings of left- and right-active individuals emerged in the negative condition. The results are specific to the alpha frequency band. In line with previous studies, these results suggest that resting frontal alpha-asymmetry reflects a person's predisposition to respond affectively. PMID:19500651

Schmidt, Barbara; Hanslmayr, Simon



Distraction affects frontal alpha rhythms related to expectancy of pain: An EEG study  

Microsoft Academic Search

Previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (Babiloni, C., Brancucci, A., Babiloni, F., Capotosto, P., Carducci, F., Cincotti, F., Arendt-Nielsen, L., Chen, A.C., Rossini, P.M., 2003. Anticipatory cortical responses during the expectancy of a predictable painful stimulation. A high-resolution electroencephalography study. Eur.

Claudio Del Percio; Domenica Le Pera; Lars Arendt-Nielsen; Claudio Babiloni; Alfredo Brancucci; Andrew C. N. Chen; Liala De Armas; Roberto Miliucci; Domenico Restuccia; Massimiliano Valeriani; Paolo Maria Rossini



Lateral inhibition in neural networks and the shape of EEG alpha rhythm waves  

Microsoft Academic Search

Baseline EEG traces were recorded from the right occipital area with the eyes closed in 15 subjects. Rhythmic stimulation\\u000a with bright, diffuse flashes of light was applied through the closed eyelids at specific points in the alpha-wave phase (trigger\\u000a photic stimulation). Ten versions of stimulation were used, with application at different phases for 1 min at each phase.\\u000a Responses occurring

D. R. Belov; O. V. Getmanenko; S. F. Kolodyazhanyi; I. E. Kanunikov



Long-Range Correlation in alpha-Wave Predominant EEG in Human  

Microsoft Academic Search

The background noise in the alpha-predominant EEG taken from eyes-open and eyes-closed neurophysiological states is studied. Scale-free characteristic is found in both cases using the wavelet approach developed by Simonsen and Nes [1]. The numerical results further show the scaling exponent during eyes-closed is consistently lower than eyes-open. We conjecture the origin of this difference is related to the temporal

Asif Sharif; Der Chyan Lin; Hon Kwan; D. S. Borette



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


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

Stinson, Bruce; Arthur, David



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


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

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



Distraction affects frontal alpha rhythms related to expectancy of pain: an EEG study.  


Previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (Babiloni, C., Brancucci, A., Babiloni, F., Capotosto, P., Carducci, F., Cincotti, F., Arendt-Nielsen, L., Chen, A.C., Rossini, P.M., 2003. Anticipatory cortical responses during the expectancy of a predictable painful stimulation. A high-resolution electroencephalography study. Eur. J. Neurosci. 18 (6) 1692-700). This study tested the hypothesis that alpha ERD before predictable painful stimuli is reduced as an effect of distraction. A visual warning stimulus preceded a laser painful stimulation, which was strictly followed by visual imperative stimuli. In the Pain (control) condition, no task was required after the imperative stimuli. In the Pain + Movement condition, subjects had to perform a movement of the right index finger. In the Pain + Cognition condition, they had to mentally perform an arithmetical task. EEG data were recorded in 10 subjects from 30 electrodes. Artifact-free recordings were spatially enhanced by surface Laplacian transformation. Alpha ERD was computed at three alpha sub-bands according to subjects' individual alpha frequency peak (i.e., about 6-8 Hz, 8-10 Hz, 10-12 Hz). Compared to the control condition, the subjects reported a significantly lower stimulus intensity perception and unpleasantness in the Pain + Movement and Pain + Cognition conditions. In addition, there was a cancellation of the alpha 3 ERD (i.e., about 10-12 Hz) in Pain + Cognition condition and even a generation of a statistically significant alpha 3 ERS in Pain + Movement condition. These effects were maximum over fronto-central midline. These results suggest that distraction during the expectancy of pain is related to a reduced neural desynchronization of fronto-central midline alpha rhythms (i.e., reduced cortical activation) towards an overt hyper-synchronization (cortical idling). PMID:16529953

Del Percio, Claudio; Le Pera, Domenica; Arendt-Nielsen, Lars; Babiloni, Claudio; Brancucci, Alfredo; Chen, Andrew C N; De Armas, Liala; Miliucci, Roberto; Restuccia, Domenico; Valeriani, Massimiliano; Rossini, Paolo Maria



Novel seizure phenotype and sleep disruptions in knock-in mice with hypersensitive alpha 4* nicotinic receptors.  


A leucine to alanine substitution (L9'A) was introduced in the M2 region of the mouse alpha4 neuronal nicotinic acetylcholine receptor (nAChR) subunit. Expressed in Xenopus oocytes, alpha4(L9'A)beta2 nAChRs were > or =30-fold more sensitive than wild type (WT) to both ACh and nicotine. We generated knock-in mice with the L9'A mutation and studied their cellular responses, seizure phenotype, and sleep-wake cycle. Seizure studies on alpha4-mutated animals are relevant to epilepsy research because all known mutations linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) occur in the M2 region of alpha4or beta2 subunits. Thalamic cultures and synaptosomes from L9'A mice were hypersensitive to nicotine-induced ion flux. L9'A mice were approximately 15-fold more sensitive to seizures elicited by nicotine injection than their WT littermates. Seizures in L9'A mice differed qualitatively from those in WT: L9'A seizures started earlier, were prevented by nicotine pretreatment, lacked EEG spike-wave discharges, and consisted of fast repetitive movements. Nicotine-induced seizures in L9'A mice were partial, whereas WT seizures were generalized. When L9'A homozygous mice received a 10 mg/kg nicotine injection, there was temporal and phenomenological separation of mutant and WT-like seizures: an initial seizure approximately 20 s after injection was clonic and showed no EEG changes. A second seizure began 3-4 min after injection, was tonic-clonic, and had EEG spike-wave activity. No spontaneous seizures were detected in L9'A mice during chronic video/EEG recordings, but their sleep-wake cycle was altered. Our findings show that hypersensitive alpha4* nicotinic receptors in mice mediate changes in the sleep-wake cycle and nicotine-induced seizures resembling ADNFLE. PMID:16339034

Fonck, Carlos; Cohen, Bruce N; Nashmi, Raad; Whiteaker, Paul; Wagenaar, Daniel A; Rodrigues-Pinguet, Nivalda; Deshpande, Purnima; McKinney, Sheri; Kwoh, Steven; Munoz, Jose; Labarca, Cesar; Collins, Allan C; Marks, Michael J; Lester, Henry A



Heart beats brain: The problem of detecting alpha waves by neuronal current imaging in joint EEG–MRI experiments  

Microsoft Academic Search

It has been suggested recently that the influence of the neuro-magnetic field should make electrical brain activity directly detectable by MRI. To test this hypothesis, we performed combined EEG–MRI experiments which aim to localize the neuronal current sources of alpha waves (8–12 Hz), one of the most prominent EEG phenomena in humans. A detailed analysis of cross-spectral coherence between simultaneously recorded

H. Mandelkow; P. Halder; D. Brandeis; M. Soellinger; N. de Zanche; R. Luechinger; P. Boesiger



EEG-based upper-alpha neurofeedback for cognitive enhancement in major depressive disorder: A preliminary, uncontrolled study.  


Conditioning of the upper-alpha rhythm to improve cognitive performance in healthy users by means of neurofeedback (NF) has been evaluated by several studies, however its effectiveness in people with severe cognitive deficits, such as depressive subjects, remains underexplored. This paper reports on a preliminary uncontrolled study to assess the effects of an upper-alpha NF intervention on patients with major depressive disorder (MDD). The NF effects on the EEG and cognitive performance were assessed. The EEG results showed that patients were able to modulate the upper-alpha rhythm in task-related EEG and during training, in both cases across the executions of the NF sessions, and pre and post within each session. The behavioral results showed the effectiveness of this intervention in a variety of cognitive functions such as working memory, attention, and executive functions. PMID:24111179

Escolano, C; Navarro-Gil, M; Garcia-Campayo, J; Minguez, J



ADHD Familial Loading and Abnormal EEG Alpha Asymmetry in Children with ADHD1  

PubMed Central

Objective Abnormal brain laterality (ABL) is indicated in ADHD. ADHD and brain laterality are heritable. Genetic factors contributing to lateralization of brain function may contribute to ADHD. If so, increased ADHD family loading should be associated with greater ABL. Previous studies have shown increased rightward alpha asymmetry in ADHD. We tested whether this was more pronounced in ADHD children with increased ADHD family loading. Methods We compared EEG alpha asymmetry at rest and during the Conner’s Continuous Performance Test (CPT) in ADHD children with and without ADHD affected parents, and replicated our findings in a second larger sample. The replication study additionally stratified the parent-affected sample by parental persistent versus non-persistent ADHD status, increased spatial resolution of EEG measures, and assessed low versus high alpha. Results Study-1: The parent-affected group showed increased rightward asymmetry across frontal and central regions and reduced rightward parietal asymmetry during an eyes closed (EC) condition, as well as increasing rightward parietal asymmetry with advancing age during the CPT. Study-2 replicated these findings and further delineated influences of low versus high alpha, recording site, and effects of parental persistent versus non-persistent ADHD status. Conclusion Increased ADHD familial loading was associated with increased rightward frontal asymmetry. In contrast, increased rightward parietal asymmetry was associated with reduced ADHD family loading. Frontal results are consistent with an ADHD endophenotype. Parietal results suggest an ADHD adaptive trait prevalent with less ADHD family loading. Age effects indicate a unique developmental course among ADHD children whose parents have non-persistent ADHD.

Hale, T. Sigi; Smalley, Susan L.; Dang, Jeff; Hanada, Grant; Macion, James; Loo, Sandra K.



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

Microsoft Academic Search

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

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



Is Resting Anterior EEG Alpha Asymmetry a Trait Marker for Depression? Findings for Healthy Adults and Clinically Depressed Patients  

Microsoft Academic Search

Several lines of evidence suggest that asymmetric ante- rior brain activation is related to affective style, linking left hemisphere activation to positive affect and right hemisphere activation to negative affect. However, pre- vious reports of left frontal hypoactivation in depressed patients were not confirmed in recent studies. This study evaluated additional characteristics of resting EEG alpha (8-13 Hz) asymmetry in

Stefan Debener; André Beauducel; Doreen Nessler; Burkhard Brocke; Hubert Heilemann



Trial-by-Trial Variations in Subjective Attentional State are Reflected in Ongoing Prestimulus EEG Alpha Oscillations  

PubMed Central

Parieto-occipital electroencephalogram (EEG) alpha power and subjective reports of attentional state are both associated with visual attention and awareness, but little is currently known about the relationship between these two measures. Here, we bring together these two literatures to explore the relationship between alpha activity and participants’ introspective judgments of attentional state as each varied from trial-to-trial during performance of a visual detection task. We collected participants’ subjective ratings of perceptual decision confidence and attentional state on continuous scales on each trial of a rapid serial visual presentation detection task while recording EEG. We found that confidence and attentional state ratings were largely uncorrelated with each other, but both were strongly associated with task performance and post-stimulus decision-related EEG activity. Crucially, attentional state ratings were also negatively associated with prestimulus EEG alpha power. Attesting to the robustness of this association, we were able to classify attentional state ratings via prestimulus alpha power on a single-trial basis. Moreover, when we repeated these analyses after smoothing the time series of attentional state ratings and alpha power with increasingly large sliding windows, both the correlations and classification performance improved considerably, with the peaks occurring at a sliding window size of approximately 7?min worth of trials. Our results therefore suggest that slow fluctuations in attentional state in the order of minutes are reflected in spontaneous alpha power. Since these subjective attentional state ratings were associated with objective measures of both behavior and neural activity, we suggest that they provide a simple and effective estimate of task engagement that could prove useful in operational settings that require human operators to maintain a sustained focus of visual attention.

Macdonald, James S. P.; Mathan, Santosh; Yeung, Nick



“Feeling” the pain of those who are different from us: Modulation of EEG in the mu\\/alpha range  

Microsoft Academic Search

We explored how apparently painful stimuli and the ability to identify with the person on whom the pain is inflicted modulate\\u000a EEG suppression in the mu\\/alpha range (8–12 Hz). In a 2 × 2 design, we presented pictures of hands either experiencing needle\\u000a pricks or being touched by a Q-tip. In the dissimilar-other condition, the hand was assigned to a

Anat Perry; Shlomo Bentin; Inbal Ben-Ami Bartal; Claus Lamm; Jean Decety



Expectancy of Pain Is Influenced by Motor Preparation: A High-Resolution EEG Study of Cortical Alpha Rhythms  

Microsoft Academic Search

This high-resolution electroencephalographic (EEG) study on alpha event-related desynchronization (ERD) evaluated whether anticipatory activity precedes a sensorimotor interaction induced by concomitant painful stimuli and sensorimotor demand. An omitted-stimulus paradigm induced the expectancy of the painful stimulation at the left hand. In the experimental condition, the painful stimulation was associated with a visual go\\/no-go task triggering right-hand movements. Two control conditions

Claudio Babiloni; Alfredo Brancucci; Paolo Capotosto; Lars Arendt-Nielsen; Andrew C. N. Chen; Paolo Maria Rossini



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

PubMed Central

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.

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



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

|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)|

Holmes, David S.; And Others



The TNFalpha gene relates to clinical phenotype in alpha-1-antitrypsin deficiency  

Microsoft Academic Search

BACKGROUND: Genetic variation may underlie phenotypic variation in chronic obstructive pulmonary disease (COPD) in subjects with and without alpha 1 antitrypsin deficiency (AATD). Genotype specific sub-phenotypes are likely and may underlie the poor replication of previous genetic studies. This study investigated subjects with AATD to determine the relationship between specific phenotypes and TNF? polymorphisms. METHODS: 424 unrelated subjects of the

Alice M Wood; Matthew J Simmonds; Darren L Bayley; Paul R Newby; Stephen C Gough; Robert A Stockley



Different slopes for different folks: alpha and delta EEG power predict subsequent video game learning rate and improvements in cognitive control tasks.  


We hypothesized that control processes, as measured using electrophysiological (EEG) variables, influence the rate of learning of complex tasks. Specifically, we measured alpha power, event-related spectral perturbations (ERSPs), and event-related brain potentials during early training of the Space Fortress task, and correlated these measures with subsequent learning rate and performance in transfer tasks. Once initial score was partialled out, the best predictors were frontal alpha power and alpha and delta ERSPs, but not P300. By combining these predictors, we could explain about 50% of the learning rate variance and 10%-20% of the variance in transfer to other tasks using only pretraining EEG measures. Thus, control processes, as indexed by alpha and delta EEG oscillations, can predict learning and skill improvements. The results are of potential use to optimize training regimes. PMID:23095124

Mathewson, Kyle E; Basak, Chandramallika; Maclin, Edward L; Low, Kathy A; Boot, Walter R; Kramer, Arthur F; Fabiani, Monica; Gratton, Gabriele



Changes in alpha band EEG activity in the frontal area after stimulation with music of different affective content.  


This study investigated the stimulating effects of music. Twelve-channel EEGs( Fp1, Fp2, F7, F8, Fz, C3, C4, Pz, T5, T6, O1, O2) were recorded on 10 students during periods of baseline, premusic rest, music (stimulating or calming), and postmusic rest. The amplitude of the alpha-2 (9.6 to 11.4 Hz) band was lower during the rest session than that during the baseline session. In the music period the amplitude of alpha-2 band increased during both the stimulating and calm music. The frontal interhemispheric coherence values (F7-F8) of the alpha-2 band increased during the stimulating music session, while the coherence values did not change during the calm music. These findings implied close relationships between the interhemispheric transmission of information in the frontal areas and positive attention to stimulating music. PMID:9106843

Iwaki, T; Hayashi, M; Hori, T



Reactivity of alpha rhythms to eyes opening is lower in athletes than non-athletes: A high-resolution EEG study  

Microsoft Academic Search

In the present study, we tested the hypothesis that compared with non-athletes, elite athletes are characterized by a reduction of reactivity of electroencephalographic (EEG) alpha rhythms (about 8–12Hz) to eyes opening in the condition of resting state, as a possible index of spatially selective cortical activation (i.e. “neural efficiency”). EEG data (56 channels; Eb-Neuro©) were recorded in 18 elite karate

Claudio Del Percio; Francesco Infarinato; Nicola Marzano; Marco Iacoboni; Pierluigi Aschieri; Roberta Lizio; Andrea Soricelli; Cristina Limatola; Paolo M. Rossini; Claudio Babiloni


Stress, emotion regulation and cognitive performance: the predictive contributions of trait and state relative frontal EEG alpha asymmetry.  


The relationship between trait and state measures of frontal lobe EEG alpha-band asymmetry in regard to indexing the approach-withdrawal dimension of emotion is unclear. The comparative predictive power of these constructs to explain emotion regulation and cognitive performance was examined under varying degrees of emotional challenge. The Capability Model posits the neural underpinnings of the relative difference in electrical activity between the left and right frontal lobes as a situational mechanism possibly indexing prefrontal-amygdalar interactions and psychological state. EEG, skin conductance, heart rate and acoustic startle amplitude were collected during a working memory task under three increasing levels of stress (final level was threat of shock). During threat of shock participants with higher state asymmetry exhibited greater emotion regulation compared to those with lower scores as indexed by significant attenuation of eyeblink startle magnitudes. The trait measure of frontal EEG asymmetry failed to account for significant variability in emotion regulation. Results implicate state-specific relative left frontal lobe activity as having an adaptive role in the regulation of emotion during cognitive challenge, but only under conditions of sufficient stress. PMID:23022494

Goodman, Ronald N; Rietschel, Jeremy C; Lo, Li-Chuan; Costanzo, Michelle E; Hatfield, Bradley D



Human anterior and frontal midline theta and lower alpha reflect emotionally positive state and internalized attention: high-resolution EEG investigation of meditation  

Microsoft Academic Search

EEG spectral power and coherence estimates in the individually defined delta, theta, alpha-1, alpha-2, and alpha-3 bands were used to identify and characterize brain regions involved in meditative states, in which focused internalized attention gives rise to emotionally positive ‘blissful’ experience. Blissful state was accompanied by increased anterior frontal and midline theta synchronization as well as enhanced theta long-distant connectivity

L. I. Aftanas; S. A. Golocheikine



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

PubMed Central

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.

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



Sensitivity of alpha and beta oscillations to sensorimotor characteristics of action: an EEG study of action production and gesture observation.  


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

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



"Feeling" the pain of those who are different from us: Modulation of EEG in the mu/alpha range.  


We explored how apparently painful stimuli and the ability to identify with the person on whom the pain is inflicted modulate EEG suppression in the mu/alpha range (8-12 Hz). In a 2 × 2 design, we presented pictures of hands either experiencing needle pricks or being touched by a Q-tip. In the dissimilar-other condition, the hand was assigned to a patient suffering from a neurological disease in which Q-tips inflicted pain, whereas needle pricks did not. In the similar-other condition, the hand was assigned to a patient who responded to stimulation in the same way as the healthy participant. Participants were instructed to imagine the feeling of the person whose hand was shown and to evaluate his or her affective state. Pain conditions elicited greater EEG suppression than did nonpain conditions, particularly over frontocentral regions. Moreover, an interaction between pain and similarity revealed that for similar others, the pain effect was significant, whereas in the dissimilar-other group, suppression was equally large in the pain and no-pain conditions. We conclude that mu/alpha suppression is elicited both automatically, by observing a situation that is potentially painful for the observer, and by empathy for pain, even if the other person is different from oneself. PMID:21098810

Perry, Anat; Bentin, Shlomo; Bartal, Inbal Ben-Ami; Lamm, Claus; Decety, Jean



Correlation between integrin alpha 5 expression and the malignant phenotype of transitional cell carcinoma.  

PubMed Central

We examined the expression of alpha 1, alpha 2, alpha 3, alpha 4, alpha 5 and beta 1 integrin on 36 transitional cell cancers (TCCs) in the bladder by immunohistochemistry. Only alpha 2, alpha 3 and beta 1 were detected on normal transitional cell epithelium, but four TCCs (12.5%) revealed positive staining for alpha 1, seven (19.4%) for alpha 4 and seven (20%) for alpha 5. These altered expressions of integrin alpha chain were more frequent in histologically higher stage or grade of TCC, and a correlation was found between increased alpha 5 expression and histological stage. alpha 5 was positive in 6 (35.3%) of 17 invasive TCCs whereas only 1 (5.9%) of 17 superficial TCCs. Flow cytometric analysis on bladder cancer cell lines showed that T24 and HT1376, which are undifferentiated TCC cell lines, highly expressed alpha 5 and beta 1. Also, SCaBER, which is derived from urinary bladder squamous cell cancer and which is recognised as the most malignant phenotype after metaplasia of transitional epithelium, had alpha 5 and beta 1. However, RT4, which is derived from transitional cell papilloma, showed no expression of alpha 5. Furthermore, reverse transcriptase-polymerase chain reaction (RT-PCR) showed the presence of mRNA of alpha 5 on T24, SCaBER and HT1376, but not on RT4. Taken together, it seems that the presence of alpha 5 integrin might be a more malignant phenotype in transitional cell carcinoma. Images Figure 1 Figure 3

Saito, T.; Kimura, M.; Kawasaki, T.; Sato, S.; Tomita, Y.



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

Microsoft Academic Search

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

Andreas Fink; Barbara Graif; Aljoscha C. Neubauer



Not all errors are alike: theta and alpha EEG dynamics relate to differences in error-processing dynamics.  


Performance errors in conflict tasks often result from inappropriate action impulses, and are thought to signal the need for increased control over the motor system. However, errors may also result from lapses in sustained attention, which may require different monitoring and adaptation mechanisms. Distinguishing between the mechanisms of adaptation is important as both error types may occur intermixed. To this end, we measured EEG of healthy human subjects while they performed three variants of the Simon task in which errors were more likely to occur due to attentional lapses, failures of motor control, or both. Behavioral results showed that subjects exhibited less conflict effects and less impulsive errors in sustained attention compared with the other Simon conditions. Time-frequency analyses of EEG data showed that the sustained attention Simon condition, compared with the motor control Simon condition, was characterized by: (1) less error-related MFC theta (4-8 Hz) power and an absence of error-related MFC-DLPFC theta phase synchronization; (2) stronger error-related suppression of parieto-occipital alpha (8-12 Hz) power and stronger parieto-occipital-frontal alpha synchronization. A control experiment, using SART (the Sustained Attention to Response Test), confirmed that adaptation after attentional lapses involved posterior alpha power suppression, in addition to inter-regional frontal theta activity. Together, these results suggest that at least two cortical mechanisms exist for performance monitoring, and that different tasks and task-settings can recruit these mechanisms in a different way. Post-error brain dynamics thus consist of heterogeneous activity from multiple neurocognitive processes. PMID:23175833

van Driel, Joram; Ridderinkhof, K Richard; Cohen, Michael X



Ventral prefrontal cortex and serotonergic system activation during pedaling exercise induces negative mood improvement and increased alpha band in EEG.  


This study evaluates a possible involvement of the prefrontal cortex (PFC) and serotonergic (5-HT) system in psychiatric and electroencephalography (EEG) changes during and after pedaling exercise (PE). The subjects performed PE for 15 min using a cycle ergometer. PE rate was kept at 60 rpm, and the work load (93+/-5.4 W) was decided for each subject before the experiment based on a Rating of Perceived Exertion of 12-13 for self-selected exercise intensity. Cerebral oxygenation in the PFC was assessed by concentration changes in oxygenated hemoglobin (oxyHb) using 24-channel near-infrared spectroscopy. We found that PE evoked a significant increase in oxyHb levels in the ventral PFC during PE as compared with that in the dorsal PFC. Subjects had a feeling of reduced negative mood accompanied by a tendency of increased vigor-activity after PE, as assessed by the Profile of Mood States (POMS) questionnaire. Because the ventral PFC is associated with mood state, we hypothesized that the observed mood changes may have been induced by the activation of the ventral PFC. As for EEG changes during and after PE, we found a significant increase in the relative powers of high-frequency alpha bands (10-13 Hz) during and after PE. A significant increase in whole blood 5-HT level was obtained after PE. Because cortical attenuation would be caused by the 5-HT-induced inhibition of the basal forebrain, we hypothesized that the observed EEG changes are linked with the increased blood 5-HT level or an augmentation of the 5-HT system in the brainstem. PMID:20412817

Fumoto, Masaki; Oshima, Tsutomu; Kamiya, Kiyoshi; Kikuchi, Hiromi; Seki, Yoshinari; Nakatani, Yasushi; Yu, Xinjun; Sekiyama, Tamami; Sato-Suzuki, Ikuko; Arita, Hideho



Pain assessment by continuous EEG: Association between subjective perception of tonic pain and peak frequency of alpha oscillations during stimulation and at rest  

Microsoft Academic Search

Recordings of neurophysiological brain responses to noxious stimuli have been traditionally based on short stimuli, in the order of milliseconds, which induce distinct event-related potentials (ERPs). However, using such stimuli in the experimental setting is disadvantageous as they are too brief to faithfully simulate clinical pain. We aimed at utilizing continuous EEG to investigate the properties of peak alpha frequency

Rony-Reuven Nir; Alon Sinai; Einat Raz; Elliot Sprecher; David Yarnitsky



Developmental Differences in the Relationship Between Reading Comprehension and Hemispheric Alpha Patterns: An EEG Study  

Microsoft Academic Search

Boys 6–8 and 10–12 years of age read short passages at their instructional level and were subsequently asked questions on these passages. EEG measures were obtained during silent reading of each passage. There were age differences in the relationship between hemisphere activation during silent reading and reading comprehension. Left-hemispheric activation was significantly associated with comprehension for the younger children. Bilateral

Theresa A. Roberts; R. Harter Kraft



The expanding phenotype of laminin alpha2 chain (merosin) abnormalities: case series and review.  


Initial reports of patients with laminin alpha2 chain (merosin) deficiency had a relatively homogeneous phenotype, with classical congenital muscular dystrophy (CMD) characterised by severe muscle weakness, inability to achieve independent ambulation, markedly raised creatine kinase, and characteristic white matter hypodensity on cerebral magnetic resonance imaging. We report a series of five patients with laminin alpha2 deficiency, only one of whom has this severe classical CMD phenotype, and review published reports to characterise the expanded phenotype of laminin alpha2 deficiency, as illustrated by this case series. While classical congenital muscular dystrophy with white matter abnormality is the commonest phenotype associated with laminin alpha2 deficiency, 12% of reported cases have later onset, slowly progressive weakness more accurately designated limb-girdle muscular dystrophy. In addition, the following clinical features are reported with increased frequency: mental retardation (~6%), seizures (~8%), subclinical cardiac involvement (3-35%), and neuronal migration defects (4%). At least 25% of patients achieve independent ambulation. Notably, three patients with laminin alpha2 deficiency were asymptomatic, 10 patients had normal MRI (four with LAMA2 mutations reported), and between 10-20% of cases had maximum recorded creatine kinase of less than 1000 U/l. LAMA2 mutations have been identified in 25% of cases. Sixty eight percent of these have the classical congenital muscular dystrophy, but this figure is likely to be affected by ascertainment bias. We conclude that all dystrophic muscle biopsies, regardless of clinical phenotype, should be studied with antibodies to laminin alpha2. In addition, the use of multiple antibodies to different regions of laminin alpha2 may increase the diagnostic yield and provide some correlation with severity of clinical phenotype. PMID:11584042

Jones, K J; Morgan, G; Johnston, H; Tobias, V; Ouvrier, R A; Wilkinson, I; North, K N



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

Microsoft Academic Search

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

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



Age effects on visual EEG responses reveal distinct frontal alpha networks  

Microsoft Academic Search

Objectives: The present study aimed to describe the effect of aging on single-trial visual alpha responses.Methods: Visual evoked potentials were recorded at F3, Cz, P3, and O1 in 12 young (20–30-year-olds) and in 10 middle-aged adults (50–55-year-olds). Slow (7–10Hz) and fast (10–15Hz) alpha frequency bands were analyzed. Three parameters of single alpha responses were assessed for the 0–300ms period after

Vasil Kolev; Juliana Yordanova; Canan Basar-Eroglu; Erol Basar



Changes in alpha band activity associated with application of the compression of fourth ventricular (CV-4) osteopathic procedure: a qEEG pilot study.  


The compression of the fourth ventricle (CV-4) is one of the more well known procedures in the cranial manipulation curriculum and practice. Cranial manipulation has received criticism because of the subtle, difficult to learn techniques, controversy over whether or not cranial bone structures move, and what if any clinical effects have been shown. The aim of this study was to measure the effects of CV-4 in 10 healthy subjects through quantitative electroencephalography (qEEG), specifically in alpha band. Participants were randomly distributed in control, sham-CV4 and CV4 conditions using a cross-over design. qEEG activity was recorded for each of the 10 subjects in each of the 3 conditions. There was a significant increase in the alpha absolute power between pre and post in the CV-4 condition. There appears to be potential for understanding the effect of the CV-4 if these finding are replicated in further clinical trials. PMID:23768271

Miana, Luiz; Bastos, Victor Hugo do Vale; Machado, Sergio; Arias-Carrión, Oscar; Nardi, Antonio Egidio; Almeida, Laís; Ribeiro, Pedro; Machado, Dionis; King, Hollis; Silva, Julio Guilherme



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

PubMed Central

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.

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



Pulsed out of awareness: EEG alpha oscillations represent a pulsed-inhibition of ongoing cortical processing.  


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

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



A possible role of evoked alpha in primary sensory processing: common properties of cat intracranial recordings and human EEG and MEG  

Microsoft Academic Search

Regarding the evoked potential (EP) as a superposition of evoked EEG rhythms in several frequency ranges, we investigated the following issue: Are distinct evoked rhythms, in particular the alpha (8–15 Hz) response, related to separable physiological processes? Frequency domain analysis of EPs was used to evaluate results of cross-modality experiments, i.e.: responses to auditory stimuli were simultaneously recorded from the

M Schürmann; C Ba?ar-Eroglu; E Ba?ar



Exploring motor system contributions to the perception of social information: Evidence from EEG activity in the mu\\/alpha frequency range  

Microsoft Academic Search

pPutative contributions of a human mirror neuron system (hMNS) to the perception of social information have been assessed by measuring the suppression of EEG oscillations in the mu\\/alpha (8-12 Hz), beta (15-25 Hz) and low-gamma (25-25 Hz) ranges while participants processed social information revealed by point-light displays of human motion. Identical dynamic displays were presented and participants were instructed to

Anat Perry; Nikolaus F. Troje; Shlomo Bentin



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

SciTech Connect

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.

Sinnecker, G.H.G; Hiort, O.; Kruse, K.; Dibbelt, L. [Medical Univ. of Luebeck (Germany)] [and others



Mu and alpha EEG rhythms during the arrest reaction in microgravity  

Microsoft Academic Search

Mu and alpha oscillations (8–12 Hz) are the most prominent electroencephalographic rhythms observed in awake, relaxed subjects.\\u000a Different cortical sources may participate in these oscillations and appear to be modulated by the sensorimotor context and\\u000a functional demands. In microgravity, the marked reduction in multimodal graviceptive inputs to cortical networks participating\\u000a in the representation of space could be expected to affect

A. Leroy; C. De Saedeleer; A. Bengoetxea; A. Cebolla; F. Leurs; B. Dan; A. Berthoz; J. McIntyre; G. Cheron



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


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

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



EEG-Based Personalized Medicine in ADHD: Individual Alpha Peak Frequency as an Endophenotype Associated with Nonresponse  

Microsoft Academic Search

This review article summarizes some recent developments in psychiatry such as personalized medicine, employing biomarkers and endophenotypes, and developments collectively referred to as neuromodulation with a focus on ADHD. Several neurophysiological subtypes in ADHD and their relation to treatment outcome are reviewed. In older research the existence of an “abnormal EEG” or “paroxysmal EEG” was often reported, most likely explained

Martijn Arns



Spatio-temporal dynamics of human EEG alpha activity during resting state  

NASA Astrophysics Data System (ADS)

Spatio-temporal dynamics of alpha activity during the resting state is characterized by alternation between ordered and disordered states. The ordered state exhibits a variety of phase patterns. We found that the duration distributions of these states and phase patterns obey power laws. These results suggest that the appearance of phase patterns and the alternation between ordered and disordered states are not just due to noise but products of internal dynamics of the brain. We discuss the possibility that these dynamics are manifestation of chaotic itinerancy in the brain dynamics.

Ito, Junji; Nikolaev, Andrey R.; van Leeuwen, Cees



Negative Covariation between Task-related Responses in Alpha/Beta-Band Activity and BOLD in Human Sensorimotor Cortex: an EEG and fMRI Study of Motor Imagery and Movements  

PubMed Central

Similar to the occipital alpha rhythm, electroencephalographic (EEG) signals in the alpha- and beta-frequency bands can be suppressed by movement or motor imagery and have thus been thought to represent the “idling state” of the sensorimotor cortex. A negative correlation between spontaneous alpha EEG and blood-oxygen-level-dependent (BOLD) signals has been reported in combined EEG and fMRI (functional Magnetic Resonance Imaging) experiments when subjects stayed at the resting state or alternated between the resting state and a task. However, the precise nature of the task-induced alpha modulation remains elusive. It was not clear whether alpha/beta rhythm suppressions may co-vary with BOLD when conducting tasks involving varying activations of the cortex. Here, we quantified the task-evoked responses of BOLD and alpha/beta-band power of EEG directly in the cortical source domain, by using source imaging technology, and examined their covariation across task conditions in a mixed block and event-related design. In this study, 13 subjects performed tasks of right hand, right foot or left hand movement and motor imagery when EEG and fMRI data were separately collected. Task-induced increase of BOLD signal and decrease of EEG amplitudes in alpha and beta bands were shown to be co-localized at the somatotopic sensorimotor cortex. At the corresponding regions, the reciprocal changes of the two signals co-varied in the magnitudes across imagination and movement conditions. The spatial correspondence and negative covariation between the two measurements was further shown to exist at somatotopic brain regions associated with different body parts. These results suggest an inverse functional coupling between task-induced changes of BOLD and low-frequency EEG signals.

Yuan, Han; Liu, Tao; Szarkowski, Rebecca; Rios, Cristina; Ashe, James; He, Bin



Reciprocal dynamics of EEG alpha and delta oscillations during spontaneous blinking at rest: a survey on a default mode-based visuo-spatial awareness.  


By means of a narrowband wavelet analysis (0.5-6Hz), EEG delta event-related oscillations (EROs), both time- and phase-locked to spontaneous blinking (delta blink-related oscillations or delta BROs), have recently been demonstrated. On the basis of their spatiotemporal characteristics, delta BROs have been proposed as being involved in an automatic mechanism of maintaining awareness in a visuo-spatial context. The aim of the present study was: a) to investigate whether spontaneous blinking was also able to modulate alpha oscillations and, if so, b) whether this modulation was consistent with delta BROs, in order c) to acquire additional information for a better understanding of the cognitive phenomena underlying blinking. Using a broadband (0.5-100 Hz) continuous wavelet transform (CWT), we analysed a total of 189 three-second EEG epochs time-locked to the blinks of seven healthy volunteers. The EEG signals were submitted both to band-pass filtered cross-trial averaging (to obtain frequency-specific BROs) and to alpha event-related synchronization/desynchronization (i.e., blink-related synchronization/desynchronization, BRS/BRD). The alpha oscillations showed: a) an early BRS; b) a BRD in the same temporal window of the delta BROs and, c) a late BRS. We postulate that: a) the early BRS represents the short-term memory maintenance of the last visually perceived trace of the surroundings; b) the alpha BRD is associated with the comparison between the newly perceived image of the environment and its mnestic representation, and, lastly, c) the late BRS is connected with neuronal recovery phenomena. PMID:21238505

Bonfiglio, Luca; Sello, Stefano; Carboncini, Maria Chiara; Arrighi, Pieranna; Andre, Paolo; Rossi, Bruno



HLA-A, B antigens and alpha 1-antitrypsin phenotypes in nodal generalised osteoarthritis and erosive osteoarthritis  

Microsoft Academic Search

HLA-A, B and alpha 1-antitrypsin phenotypes were studied in 90 unrelated patients with established nodal generalised osteoarthritis (OA). Compared with standard reference populations, independently increased frequency of the HLA-A1B8 and MZ alpha 1-antitrypsin phenotypes were observed (27% v 11.5%, relative risk 2.79, and 12% v 3.6%, relative risk 3.73 respectively). These associations related to developed of nodal generalised OA rather

M Pattrick; A Manhire; A M Ward; M Doherty



HIF-1{alpha} Mediates Tumor Hypoxia to Confer a Perpetual Mesenchymal Phenotype for Malignant Progression  

NSDL National Science Digital Library

Although tumor progression involves genetic and epigenetic alterations to normal cellular biology, the underlying mechanisms of these changes remain obscure. Numerous studies have shown that hypoxia-inducible factor 1&alpha; (HIF-1&alpha;) is overexpressed in many human cancers and up-regulates a host of hypoxia-responsive genes for cancer growth and survival. We recently identified an alternative mechanism of HIF-1&alpha; function that induces genetic alterations by suppressing DNA repair. Here, we show that long-term hypoxia, which mimics the tumor microenvironment, drives a perpetual epithelial-mesenchymal transition (EMT) through up-regulation of the zinc finger E-box binding homeobox protein ZEB2, whereas short-term hypoxia induces a reversible EMT that requires the transcription factor Twist1. Moreover, we show that the perpetual EMT driven by chronic hypoxia depends on HIF-1&alpha; induction of genetic alterations rather than its canonical transcriptional activator function. These mesenchymal tumor cells not only acquire tumorigenicity but also display characteristics of advanced cancers, including necrosis, aggressive invasion, and metastasis. Hence, these results reveal a mechanism by which HIF-1&alpha; promotes a perpetual mesenchymal phenotype, thereby advancing tumor progression.

Young-Gun Yoo (University of Utah;Department of Neurosurgery REV); Jared Christensen (University of Utah;Department of Neurosurgery REV); Jie Gu (University of Utah;Department of Neurosurgery REV); L. Eric Huang (University of Utah;Department of Neurosurgery REV)



EEG Fitting: A New Method for Numerical Analysis of EEG  

Microsoft Academic Search

A new method for numerical analysis of EEG is described. It consists of fitting the EEG with orthogonal polynomials in several steps to separate the different frequencies contained in the original recording (high-frequency noise, beta, sigma, alpha, theta, delta, low-frequency noise). The original EEG is separated into 5 different signals with cutoff frequencies at 40, 18, 4 and 0.6 Hz.

J.-M. Gaillard



'SZ like' alpha 1-antitrypsin phenotypes in PI ZZ children with liver disease.  


Using high resolution isoelectric focusing, alpha 1-antitrypsin phenotypes were studied in 106 individuals of the PI ZZ genotype including 71 with liver disease, 22 with chest disease and 13 healthy subjects. The resulting Z patterns were found to be highly variable. In the majority of cases (89/106) the maximum staining intensity was either in the most basic isoform or shared equally between two basic isoforms of the Z phenotype. However, in 17 cases there was a marked intensification of the more acidic isoforms resulting in a pattern which closely resembled the SZ phenotype. This 'SZ like' pattern occurred more frequently in the liver group (16/71) than the chest group (0/22) or healthy (1/13) controls. One possible consequence of the 'SZ like' pattern is confusion with the genuine SZ phenotype leading to misclassification. If this were so, there could be an erroneous exaggeration of the actual incidence of childhood liver disease associated with PI SZ. PMID:8031012

Whitehouse, D B; Lovegrove, J U; Mieli-Vergani, G; Mowat, A P; Hopkinson, D A



Correlation between integrin alpha 5 expression and the malignant phenotype of transitional cell carcinoma  

Microsoft Academic Search

We examined the expression of alpha 1, alpha 2, alpha 3, alpha 4, alpha 5 and beta 1 integrin on 36 transitional cell cancers (TCCs) in the bladder by immunohistochemistry. Only alpha 2, alpha 3 and beta 1 were detected on normal transitional cell epithelium, but four TCCs (12.5%) revealed positive staining for alpha 1, seven (19.4%) for alpha 4

T Saito; M Kimura; T Kawasaki; S Sato; Y Tomita




Microsoft Academic Search

Neurofeedback (NF) is an electroencephalographic (EEG) biofeedback technique for training individuals to alter their brain activity via operant conditioning. Research has shown that NF helps reduce symptoms of several neurological and psychiatric disorders, with ongoing research currently investigating applications to other disorders and to the enhancement of non-disordered cognition. The present article briefly reviews the fundamen- tals and current status

Efthymios Angelakis; Stamatina Stathopoulou; Jennifer L. Frymiare; Deborah L. Green; Joel F. Lubar; John Kounios



The effect of GSM-like ELF radiation on the alpha band of the human resting EEG  

Microsoft Academic Search

Mobile phone handsets such as those operating in the GSM network emit extremely low frequency electromagnetic fields ranging from DC to at least 40 kHz. As a subpart of an extended protocol, the influence of these fields on the human resting EEG has been investigated in a fully counter balanced, double blind, cross-over design study that recruited 72 healthy volunteers.

Nicholas Perentos; Rodney J. Croft; Raymond J. McKenzie; Dean Cvetkovic; Irena Cosic




Microsoft Academic Search

This paper firstly reports the visual response to the inner light (a form of qi) and the outside stimulus during Zen meditation. It has been reported literally that inner light perception is the common experience for prayers or Zen-meditation practitioners. In this paper, we propose a method to quantify the EEG (electroencephalograph) and F-VEP (flash visual evoked potential) that characterize




HLA-A, B antigens and alpha 1-antitrypsin phenotypes in nodal generalised osteoarthritis and erosive osteoarthritis.  


HLA-A, B and alpha 1-antitrypsin phenotypes were studied in 90 unrelated patients with established nodal generalised osteoarthritis (OA). Compared with standard reference populations, independently increased frequency of the HLA-A1B8 and MZ alpha 1-antitrypsin phenotypes were observed (27% v 11.5%, relative risk 2.79, and 12% v 3.6%, relative risk 3.73 respectively). These associations related to developed of nodal generalised OA rather than to severity as judged by the summated radiographic scores for hand OA. Ten patients had marked subchondral radiographic erosions and were further classified as erosive OA; these patients had an increased frequency of the MS alpha 1-antitrypsin phenotype (30% v 9%) and higher radiographic OA scores corrected for presence of erosions. This first report of two independent genetic markers in nodal generalised OA is of interest in relation to the increasingly recognised inflammatory component of the osteoarthritis process. PMID:2787142

Pattrick, M; Manhire, A; Ward, A M; Doherty, M



HLA-A, B antigens and alpha 1-antitrypsin phenotypes in nodal generalised osteoarthritis and erosive osteoarthritis.  

PubMed Central

HLA-A, B and alpha 1-antitrypsin phenotypes were studied in 90 unrelated patients with established nodal generalised osteoarthritis (OA). Compared with standard reference populations, independently increased frequency of the HLA-A1B8 and MZ alpha 1-antitrypsin phenotypes were observed (27% v 11.5%, relative risk 2.79, and 12% v 3.6%, relative risk 3.73 respectively). These associations related to developed of nodal generalised OA rather than to severity as judged by the summated radiographic scores for hand OA. Ten patients had marked subchondral radiographic erosions and were further classified as erosive OA; these patients had an increased frequency of the MS alpha 1-antitrypsin phenotype (30% v 9%) and higher radiographic OA scores corrected for presence of erosions. This first report of two independent genetic markers in nodal generalised OA is of interest in relation to the increasingly recognised inflammatory component of the osteoarthritis process.

Pattrick, M; Manhire, A; Ward, A M; Doherty, M



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

PubMed Central

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.

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



Time course and specificity of sensory-motor alpha modulation during the observation of hand motor acts and gestures: a high density EEG study  

PubMed Central

The main aim of the present study was to explore, by means of high-density EEG, the intensity and the temporal pattern of event-related sensory-motor alpha desynchronization (ERD) during the observation of different types of hand motor acts and gestures. In particular, we aimed to investigate whether the sensory-motor ERD would show a specific modulation during the observation of hand behaviors differing for goal-relatedness (hand grasping of an object and meaningless hand movements) and social relevance (communicative hand gestures and grasping within a social context). Time course analysis of alpha suppression showed that all types of hand behaviors were effective in triggering sensory-motor alpha ERD, but to a different degree depending on the category of observed hand motor acts and gestures. Meaningless gestures and hand grasping were the most effective stimuli, resulting in the strongest ERD. The observation of social hand behaviors such as social grasping and communicative gestures, triggered a more dynamic time course of ERD compared to that driven by the observation of simple grasping and meaningless gestures. These findings indicate that the observation of hand motor acts and gestures evoke the activation of a motor resonance mechanism that differs on the basis of the goal-relatedness and the social relevance of the observed hand behavior.

Streltsova, Alena; Berchio, Cristina; Gallese, Vittorio



Phenotype and Genotype in Mucolipidoses II and III alpha/beta: A Study of 61 Probands  

PubMed Central

Objectives Mucolipidoses II and III alpha/beta (ML II and ML III) are lysosomal disorders in which the essential mannose-6-phosphate recognition marker is not synthesized onto lysosomal hydrolases and other glycoproteins. The disorders are caused by mutations in GNPTAB, which encodes two of three subunits of the heterohexameric enzyme, N-acetylglucosamine-1-phosphotransferase. Clinical, biochemical, and molecular findings in 61 probands (63 patients) are presented in order to provide a broad perspective of these mucolipidoses. Methods GNPTAB was sequenced in all probands and/or parents. Activity of several lysosomal enzymes was measured in plasma, and GlcNac-1-phosphotransferase was assayed in leukocytes. Thirty-six patients were studied in detail, allowing extensive clinical data to be abstracted. Results ML II correlates with near total absence of phosphotransferase activity resulting from homozygosity or compound heterozygosity for frameshift or nonsense mutations. Craniofacial and orthopedic manifestations are evident at birth, skeletal findings become more obvious within the first year, and growth is severely impaired. Speech, ambulation, and cognitive function are impaired. ML III retains a low level of phosphotransferase activity due to at least one missense or splice site mutation. The phenotype is milder with minimal delays in milestones, the appearance of facial coarsening by early school age, and slowing of growth after age four years. Conclusions Fifty-one pathogenic changes in GNPTAB are presented, including 42 novel mutations. Ample clinical information improves criteria for delineation of ML II and ML III. Phenotype-genotype correlations suggested in more general terms in earlier reports on smaller groups of patients are specified and extended.

Cathey, Sara S.; Leroy, Jules G.; Wood, Tim; Eaves, Karisa; Simensen, Richard J.; Kudo, Mariko; Stevenson, Roger E.; Friez, Michael J.



EEG (Electroencephalograph)  

NSDL National Science Digital Library

As part of a set of materials about brain scanning technologies, this web page describes and illustrates what an EEG (electroencephalograph) is. It explains that although EEGs are not technically brain scans, they are included in the site as an example of an earlier, noninvasive technology that researchers still employ to gather brain data. EEGs record the brain's electrical activity. The text notes the kind of information that EEGs can and cannot provide to researchers and touches on its history. Copyright 2005 Eisenhower National Clearinghouse

Productions, David G.; York, Thirteen/wnet N.



Source analysis of EEG oscillations using high-resolution EEG and MEG  

PubMed Central

We investigated spatial properties of the source distributions that generate scalp electroencephalographic (EEG) oscillations. The inherent complexity of the spatiotemporal dynamics of EEG oscillations indicates that conceptual models that view source activity as consisting of only of a few “equivalent dipoles” are inadequate. We present an approach that uses volume conduction models to characterize the distinct spatial filtering of cortical source activity by average-reference EEG, high-resolution EEG, and magnetoencephalography (MEG). By comparing these three measures, we can make inferences about the sources of EEG oscillations without having to make prior assumptions about the sources. We apply this approach to spontaneous EEG oscillations observed with eyes closed at rest. Both EEG and MEG recordings show robust alpha rhythms over posterior regions of the cortex; however, the dominant frequency of these rhythms varies between EEG and MEG recordings. Frontal alpha and theta rhythms are generated almost exclusively by superficial radial dipole layers that generate robust EEG signals but very little MEG signals; these sources are presumably mainly in the gyral crowns of frontal cortex. MEG and high-resolution EEG estimates of alpha rhythms provide evidence of local tangential and radial sources in the posterior cortex, lying mainly on sulcal and gyral surfaces. Despite the detailed information about local radial and tangential sources potentially afforded by high-resolution EEG and MEG, it is also evident that the alpha and theta rhythms receive contributions from non-local source activity, for instance large dipole layers distributed over lobeal or (potentially) even larger spatial scales.

Srinivasan, Ramesh; Winter, William R.; Nunez, Paul L.



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


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

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



Tonic pain and continuous EEG: Prediction of subjective pain perception by alpha-1 power during stimulation and at rest  

Microsoft Academic Search

ObjectivePain neurophysiology has been chiefly characterized via event-related potentials (ERPs), which are exerted using brief, phase-locked noxious stimuli. Striving for objectively characterizing clinical pain states using more natural, prolonged stimuli, tonic pain has been recently associated with the individual peak frequency of alpha oscillations. This finding encouraged us to explore whether alpha power, reflecting the magnitude of the synchronized activity

Rony-Reuven Nir; Alon Sinai; Ruth Moont; Eyal Harari; David Yarnitsky


Distribution of alpha-1-antitrypsin phenotypes in two Dutch population groups  

Microsoft Academic Search

The a1-antitrypsin phenotypes of two Dutch population groups (consisting of 672 and 802 individuals) were determined by the isoelectric focusing technique, which due to its recent development, has been used for the first time in large-scale phenotyping.

J. J. M. L. Hoffmann; W. G. M. van den Brock



Common Genetic Origins for EEG, Alcoholism and Anxiety: The Role of CRH-BP  

PubMed Central

The resting EEG is a dynamic index of cortical activation, cognitive function and consciousness and is therefore an intermediate phenotype for many behaviors in which arousal is implicated such as anxiety and alcoholism. We performed a dense whole genome linkage scan using 3878 unlinked SNPs in a large pedigree derived from a population isolate sample of 328 Plains American Indians. Alpha (8–13 Hz), theta (4–8 Hz) and beta (13–30 Hz) EEG power was heritable (0.58–0.27) and stable over a 2 year period (r?=?0.82–0.53). Genetic correlations between frequency bands were high (0.75). Linkage peaks for EEG power in all three frequency bands converged on chromosome 5q13-14 with genome-wide significant LOD scores of 3.5 (empirical p<0.0001) for alpha and beta power. A logical candidate gene, corticotropin releasing hormone-binding protein (CRH-BP), was located at the apex of these convergent linkage peaks. CRH-BP was significantly associated with alpha power in the Plains Indians and also in a replication sample of 188 Caucasians. Moreover, the same SNPs and haplotypes, located within the CRH-BP haplotype block, were also associated with anxiety disorders in the Plains Indians and alcohol use disorders in the Caucasians. CRH-BP modulates CRH which influences cortical and hippocampal EEG activity and is the primary mediator of the neuroendocrine stress response. Our results suggest a likely role for CRH-BP in stress-related alcoholism and highlight the use of the resting EEG as an intermediate phenotype for arousal-related behaviors such as anxiety and addiction.

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



Adenovirus-mediated hepatocyte nuclear factor-4{alpha} overexpression maintains liver phenotype in cultured rat hepatocytes  

SciTech Connect

Hepatocyte nuclear factor 4{alpha} (HNF-4{alpha}) is a transcription factor that controls embryonal liver development and that maintains and regulates gene expression in adult liver cells. We have previously demonstrated that transient overexpression of HNF-4{alpha} up-regulates a number of liver-specific genes in hepatoma cell lines. In this study, we extend these studies by assessing the functional role of HNF-4{alpha} in regulating cellular viability and liver-specific functions of primary rat hepatocytes. In cells transfected with an adenovirus vector carrying rat HNF-4{alpha} cDNA, induction and maintenance of liver-specific genes and functions were observed over a long-term culture, which might be associated with the prevention of a rapid loss of the mitochondrial membrane potential. In addition, we demonstrated that transthyretin mRNA was up-regulated by HNF-4{alpha} in primary hepatocytes, but not in hepatoma cells. These results indicate that HNF-4{alpha} plays a role in the maintenance of morphologically and biochemically functional hepatocytes and that the difference in expression of liver-specific genes induced by HNF-4{alpha} may depend on a differentiation state of cells.

Naiki, Takafumi [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Nagaki, Masahito [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan)]. E-mail:; Asano, Takahiko [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Kimata, Takayuki [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Moriwaki, Hisataka [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan)



Memory activation enhances EEG abnormality in mild cognitive impairment  

Microsoft Academic Search

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 (4–8Hz), lower alpha

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



Wound macrophages express TGF-alpha and other growth factors in vivo: analysis by mRNA phenotyping.  


The presence of macrophages is required for the regeneration of many cell types during wound healing. Macrophages have been reported to express a wide range of mitogenic factors and cytokines, but none of these factors has been shown in vivo to sustain all the wound-healing processes. It has been suggested that transforming growth factor-alpha (TGF-alpha) may mediate angiogenesis, epidermal regrowth, and formation of granulation tissue in vivo. Macrophages isolated from a wound site, and not exposed to cell culture conditions, expressed messenger RNA transcripts for TGF-alpha, TGF-beta, platelet-derived growth factor A-chain, and insulin-like growth factor-1. The expression of these transcripts was determined by a novel method for RNA analysis in which low numbers of mouse macrophages were isolated from wound cylinders, their RNA was purified and reverse-transcribed, and the complementary DNA was amplified in a polymerase chain reaction primed with growth factor sequence-specific primers. This single-cell RNA phenotyping procedure is rapid and has the potential for quantification, and mRNA transcripts from a single cell or a few cells can be unambiguously demonstrated, with the simultaneous analysis of several mRNA species. Macrophages from wounds expressed TGF-alpha antigen, and wound fluids contained TGF-alpha. Elicited macrophages in culture also expressed TGF-alpha transcripts and polypeptide in a time-dependent manner after stimulation with modified low-density lipoproteins and lipopolysaccharide endotoxin, which are characteristic of the activators found in injured tissues. PMID:3041594

Rappolee, D A; Mark, D; Banda, M J; Werb, Z



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


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

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



Expression of mutant alpha-synuclein modulates microglial phenotype in vitro  

PubMed Central

Background Increased reactive microglia are a histological characteristic of Parkinson's disease (PD) brains, positively correlating with levels of deposited ?-synuclein protein. This suggests that microglial-mediated inflammatory events may contribute to disease pathophysiology. Mutations in the gene coding for ?-synuclein lead to a familial form of PD. Based upon our prior findings that ?-synuclein expression regulates microglial phenotype we hypothesized that expression of mutant forms of the protein may contribute to the reactive microgliosis characteristic of PD brains. Methods To quantify the effects of wild type and mutant ?-synuclein over-expression on microglial phenotype a murine microglial cell line, BV2, was transiently transfected to express human wild type (WT), and mutant ?-synuclein (A30P and A53T) proteins. Transfected cells were used to assess changes in microglia phenotype via Western blot analysis, ELISA, phagocytosis, and neurotoxicity assays. Results As expected, over-expression of ?-synuclein induced a reactive phenotype in the transfected cells. Expression of ?-synuclein increased protein levels of cycloxygenase-2 (Cox-2). Transfected cells demonstrated increased secretion of the proinflammatory cytokines, tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6), as well as increased nitric oxide production. Transfected cells also had impaired phagocytic ability correlating with decreased protein levels of lysosomal-associated membrane protein 1 (LAMP-1). In spite of the increased cytokine secretion profile, the transfected cells did not exhibit increased neurotoxic ability above control non-transfected BV2 cells in neuron-microglia co-cultures. Conclusions These data demonstrated that over-expression of ?-synuclein drives microglial cells into a form of reactive phenotype characterized by elevated levels of arachidonic acid metabolizing enzymes, cytokine secretion, and reactive nitrogen species secretion all superimposed upon impaired phagocytic potential.



Coupling between resting cerebral perfusion and EEG.  


While several studies have investigated interactions between the electroencephalography (EEG) and functional magnetic resonance imaging BOLD signal fluctuations, less is known about the associations between EEG oscillations and baseline brain haemodynamics, and few studies have examined the link between EEG power outside the alpha band and baseline perfusion. Here we compare whole-brain arterial spin labelling perfusion MRI and EEG in a group of healthy adults (n = 16, ten females, median age: 27 years, range 21-48) during an eyes closed rest condition. Correlations emerged between perfusion and global average EEG power in low (delta: 2-4 Hz and theta: 4-7 Hz), middle (alpha: 8-13 Hz), and high (beta: 13-30 Hz and gamma: 30-45 Hz) frequency bands in both cortical and sub-cortical regions. The correlations were predominately positive in middle and high-frequency bands, and negative in delta. In addition, central alpha frequency positively correlated with perfusion in a network of brain regions associated with the modulation of attention and preparedness for external input, and central theta frequency correlated negatively with a widespread network of cortical regions. These results indicate that the coupling between average EEG power/frequency and local cerebral blood flow varies in a frequency specific manner. Our results are consistent with longstanding concepts that decreasing EEG frequencies which in general map onto decreasing levels of activation. PMID:23160910

O'Gorman, R L; Poil, S-S; Brandeis, D; Klaver, P; Bollmann, S; Ghisleni, C; Lüchinger, R; Martin, E; Shankaranarayanan, A; Alsop, D C; Michels, L



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

SciTech Connect

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.

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



P2Y receptor signaling regulates phenotype and IFN-alpha secretion of human plasmacytoid dendritic cells.  


Plasmacytoid dendritic cells (PDCs) play powerful regulatory roles in innate and adaptive immune responses and are a major source of type I interferon (IFN) following viral infection. During inflammation and mechanical stress, cells release nucleotides into the extracellular space where they act as signaling molecules via G protein-coupled P2Y receptors. We have previously reported on the regulation of myeloid dendritic cell (DC) function by nucleotides. Here, we report that human PDCs express several subtypes of P2Y receptors and mobilize intracellular calcium in response to nucleotide exposure. As a functional consequence, PDCs acquire a mature phenotype that is further enhanced in the context of CD40 ligation. Strikingly, nucleotides strongly inhibit IFN-alpha secretion induced by influenza virus or CpG-A. This effect is most pronounced for the uridine nucleotides UDP and UTP and the sugar nucleotide UDP-glucose, ligands of P2Y(6), P2Y(4), and P2Y(14), respectively. Nucleotide-induced inhibition of IFN-alpha production is blocked by suramin, a P2Y receptor antagonist. Pharmacological data point toward a role of protein kinase C in the negative regulation of type I IFN. Manipulating PDC function with P2Y receptor agonists may offer novel therapeutic strategies for autoimmune diseases or cancer. PMID:17993619

Shin, Amanda; Toy, Tracey; Rothenfusser, Simon; Robson, Neil; Vorac, Julia; Dauer, Marc; Stuplich, Moritz; Endres, Stefan; Cebon, Jonathan; Maraskovsky, Eugene; Schnurr, Max



New phenotype of adult alpha-L-iduronidase deficiency (mucopolysaccharidosis I) masquerading as Friedreich's ataxia with cardiopathy.  


Clinical, ultrastructural and biochemical studies are reported in a 42-year-old woman presenting with congenital pes cavus who, at the age of 23 years, developed slowly progressive distal amyotrophies, hypesthesia, bilateral hearing loss and severe cardiopathy leading to death. There were skeletal anomalies, mild reduction of motor NCVs, but no corneal opacity, retinitis pigmentosa, organomegaly or vacuolated lymphocytes. Autopsy disclosed severe thickening of fibrous tissues (endocardium, cerebrospinal dura) with accumulation of vacuolated cells containing glycosaminoglycans in numerous membrane-bound cytoplasmic vacuoles, and/or compound multilamellar or zebra-body-like structures. The CNS, in addition to enlarged perivascular lacunes in cerebral white matter with lipid-containing macrophages, showed neuronal lipid storage in thalamus, hypothalamus, hippocampus, brain stem nuclei, spinal motor neurons and Purkinje cell dendrites. Ultrastructurally, lamellated inclusions containing gangliosides were seen in mesenchymal cells, oligodendrocytes, pericytes and Schwann cells. Neurons contained abundant ceroid but no lamellated inclusions. Neurochemistry revealed decrease of alpha-L-iduronidase activity in brain tissue to 4% of normal, normal activities of other lysosomal enzymes, and normal lipid and ganglioside patterns. While the morphology and neurochemistry data are characteristic of mucopolysaccharidosis I, the phenotype of adult alpha-L-iduronidase deficiency mimicking Friedreich's disease has not been described so far. PMID:2121405

Jellinger, K; Paulus, W; Grisold, W; Paschke, E


Human pancreatic alpha-amylase: phenotypic codominance and new electrophoretic variants.  

PubMed Central

The genetic heterogeneity of human pancreatic alpha-amylase (alpha-1,4-glucan 4-glucanohydrolase, E.C. has been better defined through the development of an asparagine buffered electrophoretic gel system. Three alleles had been identified for the pancreatic amylase locus, AMY2, with two variant alleles as autosomal dominant traits on Tris HCl buffered sheet gels. The asparagine buffered sheet gel now allows the differentiation of the genotypes AMY2B/AMY2B,AMY2B/AMY2A, and AMY2B/AMY2C, thus classifying these three alleles as codominants. Asparagine buffered polyacrylamide gels and thin layer polyacrylamide isoelectric focusing aided in the identification of three new pancreatic amylase variants: AMY2D,AMY2E, and AMY2F. AMY2E has been identified only in AMY2B and AMY2E individuals. This allele is proposed as a quantitative activity variant with essentially the same electrophoretic mobility as AMY2A. The other new autosomal variants have each been identified in single white families. AMY2D is dominant and AMY2F is a codominant trait as shown on thin layer polyacrylamide isoelectric focusing gels. Images Fig. 1 Fig. 2 Fig. 5

Rosenblum, B B; Merritt, A D



EEG and hypnotic susceptibility  

Microsoft Academic Search

59 college students volunteered for a study of brain waves subsequent to taking the Harvard Group Hypnotic Susceptibility Scale (HGS). The EEG autospectrum and cross spectrum were computed and further analyzed by stepwise regression techniques to determine EEG spectral parameters most related to hypnotic susceptibility. Results show significant EEG prediction of HGS scores. The most predictive EEG parameters were from

Gary C. Galbraith



On chronological changes in the basic EEG rhythm in persons with Down syndrome – with special reference to slowing of alpha waves  

Microsoft Academic Search

The authors tried to know specificity of aging in persons with Down syndrome (DS) from the aspect of electroencephalograph (EEG) frequency changes through the cross-sectional and longitudinal studies, in comparison with normal persons as well as those with mentally retardation except the Down syndrome (non-DS MR). Subjects for a cross-sectional study were 265 persons with DS, 242 with non-DS MR

Akiyoshi Katada; Sakurako Hasegawa; Dan Ohira; Takako Kumagai; Tsuneo Harashima; Hisaki Ozaki; Hiroya Suzuki



MCF-7 breast cancer cells transfected with protein kinase C-alpha exhibit altered expression of other protein kinase C isoforms and display a more aggressive neoplastic phenotype.  

PubMed Central

Increased protein kinase C (PKC) activity in malignant breast tissue and positive correlations between PKC activity and expression of a more aggressive phenotype in breast cancer cell lines suggest a role for this signal transduction pathway in the pathogenesis and/or progression of breast cancer. To examine the role of PKC in the progression of breast cancer, human MCF-7 breast cancer cells were transfected with PKC-alpha, and a group of heterogenous cells stably overexpressing PKC-alpha were isolated (MCF-7-PKC-alpha). MCF-7-PKC-alpha cells expressed fivefold higher levels of PKC-alpha as compared to parental or vector-transfected MCF-7 cells. MCF-7-PKC-alpha cells also displayed a substantial increase in endogenous expression of PKC-beta and decreases in expression of the novel delta- and eta-PKC isoforms. MCF-7-PKC-alpha cells displayed an enhanced proliferative rate, anchorage-independent growth, dramatic morphologic alterations including loss of an epithelioid appearance, and increased tumorigenicity in nude mice. MCF-7-PKC-alpha cells exhibited a significant reduction in estrogen receptor expression and decreases in estrogen-dependent gene expression. These findings suggest that the PKC pathway may modulate progression of breast cancer to a more aggressive neoplastic process. Images

Ways, D K; Kukoly, C A; deVente, J; Hooker, J L; Bryant, W O; Posekany, K J; Fletcher, D J; Cook, P P; Parker, P J



Effects of transcranial magnetic stimulation on EEG activity  

Microsoft Academic Search

The combination of transcranial magnetic stimulation (TMS) and an electroencephalogram (EEG) is an effective tool for investigating the functional connectivity in the brain. This paper investigated cortical reactivity and connectivity by the combination of TMS and EEG. The spontaneous activity of the brain was measured before and after magnetic stimulation. The effect of TMS on alpha activity was investigated. The

Keiji Iramina; Takashi Maeno; Yasuyuki Kowatari; Shoogo Ueno



Comparison between spectral and fractal EEG analyses of sleeping newborns  

Microsoft Academic Search

Spectral parameters (power spectrum in the delta, theta, alpha, beta1 and beta2 bands) and the fractal dimension were estimated for each two seconds frame of the EEG sleep time series at the awake condition or during one of the four EEG sleep states: active sleep (two stages: mixed and low voltage irregular) and quiet sleep (two stages: quiet sleep high

A. P. Accardo; M. Affinito; M. Carrozzi; S. Cisint; F. Bouquet



Evaluation of human stress using EEG Power Spectrum  

Microsoft Academic Search

This paper presents an evaluation conducted between human stress questionnaires with EEG Power Spectrum of Beta and Alpha band. Cohen's Perceived Stress Scale (PSS) was used as stress questionnaires to evaluate human stress. The EEG recording of 13 volunteers were carried out immediately after them answering the stress questionnaires. The scores from the stress questionnaires were calculated and used to

N. H. A. Hamid; N. Sulaiman; S. A. M. Aris; Z. H. Murat; M. N. Taib



The Utility of EEG Band Power Analysis in the Study of Infancy and Early Childhood  

Microsoft Academic Search

Research employing electroencephalographic (EEG) techniques with infants and young children has flourished in recent years due to increased interest in understanding the neural processes involved in early social and cognitive development. This review focuses on the functional characteristics of the alpha, theta, and gamma frequency bands in the developing EEG. Examples of how analyses of EEG band power have been

Joni N. Saby; Peter J. Marshall



Interhemispheric EEG asymmetries during unilateral bright-light exposure and subsequent sleep in humans  

Microsoft Academic Search

Abstract We,tested,whether,evening,exposure,to,unilateral photic,stimulation,has repercussions,on interhemispheric EEG asymmetries,during wakefulness,and later sleep. Since light exerts an alerting response in humans, which correlates with a decrease,in waking EEG theta\\/alpha-activity and,a reduction in sleep EEG delta activity, we hypothesized that EEG activity in these frequency bands show interhemisphericasymmetries,after unilateral bright light (1500 lux) exposure. A 2-h hemi-field light exposure,acutely suppressed,occipital EEG alpha activity in

Christian Cajochen; Rosalba Di Biase; Makoto Imai



Function of a rare variant of alpha-1-antitrypsin, phenotype Pi E Franklin S, a poor inhibitor of human neutrophil elastase  

Microsoft Academic Search

A 31-year-old woman with the rare alpha-1-antitrypsin (A1AT) phenotype Pi EFranklin S presented to this laboratory. Since little is known about the EFranklin protein, a study was established to investigate the biochemical properties of this glycoprotein, notably its inhibitory activity\\u000a against human neutrophil elastase (HNE), compared with that of the more common A1AT variants M and Z. The serum A1AT

Luisa Cook; Kenneth R. Knight; Jonathan G. W. Burdon; Sue Brenton; John M. Hunt



How reproducible is the topographical distribution of EEG amplitude?  


If topographical EEG is to be a useful tool for localising cerebral processes, then the results of the same, or closely similar experiments, using different samples should yield similar results. Although the reliability of EEG is well established in other ways, there is little available data on the reproducibility of EEG topography across experiments. The aim of this study was to determine the reproducibility of topographical EEG by comparing the results of two independently conducted experiments. EEG was recorded during an Eyes Open baseline and a motor task condition (the Luria finger opposition task) in two independent samples of healthy subjects. EEG was recorded in 2.56-s epochs and analysed by FFT into conventional theta, alpha and beta 1 frequency bands. The EEG amplitude for each subject in each frequency range was averaged over a minimum of 60 s. Separate group averages for each sample were calculated and the resulting topographical distributions of electrical potential and current density were compared. The results indicated that the reproducibility of electrical potential in the theta and beta 1 frequency ranges was extremely poor and only approached acceptable levels in alpha. Reproducibility of current source density was poor in all frequency ranges. Although some improvement in reproducibility was obtained following spatial smoothing for alpha potential, the highest reproducibility achieved was only 0.65. Reasons for the poor reproducibility of topographical EEG and the implications of these findings are discussed. PMID:9202998

Burgess, A P; Gruzelier, J



Differences in event-related and induced EEG patterns in the theta and alpha frequency bands related to human emotional intelligence  

Microsoft Academic Search

High (emotional intelligence scores (EIQ)=120) and average emotional intelligent individuals (EIQ=89) were solving tasks from an emotional intelligence test while their electroencephalogram was recorded. Significant differences relating to emotional intelligence were observed in induced and event related band power in the theta (4.4–6.4 Hz), lower-2 alpha (8.4–10.4 Hz), and upper alpha band (10.4–12.4 Hz). High emotional intelligent individuals displayed less

Norbert Jaušovec; Ksenija Jaušovec; Ivan Gerli?



Wound Macrophages Express TGF-alpha and Other Growth Factors in vivo: Analysis by mRNA Phenotyping  

Microsoft Academic Search

The presence of macrophages is required for the regeneration of many cell types during wound healing. Macrophages have been reported to express a wide range of mitogenic factors and cytokines, but none of these factors has been shown in vivo to sustain all the wound-healing processes. It has been suggested that transforming growth factor-alpha (TGF-alpha ) may mediate angiogenesis, epidermal

Daniel A. Rappolee; David Mark; Michael J. Banda; Zena Werb



Mucolipidosis II and III alpha\\/beta: mutation analysis of 40 Japanese patients showed genotype–phenotype correlation  

Microsoft Academic Search

Mucolipidosis (ML) II alpha\\/beta and III alpha\\/beta are autosomal recessive diseases caused by a deficiency of ? and\\/or ? subunits of the enzyme N-acetylglucosamine-1-phosphotransferase, which is encoded by the GNPTAB gene. We analyzed the GNPTAB gene in 25 ML II and 15 ML III Japanese patients. In most ML II patients, the clinical conditions ‘stand alone’, ‘walk without support’ and

Takanobu Otomo; Takeshi Muramatsu; Tohru Yorifuji; Torayuki Okuyama; Hiroki Nakabayashi; Toshiyuki Fukao; Toshihiro Ohura; Makoto Yoshino; Akemi Tanaka; Nobuhiko Okamoto; Koji Inui; Keiichi Ozono; Norio Sakai



Effect of aerobic training on EEG alpha asymmetry and depressive symptoms in the elderly: a 1-year follow-up study.  


The effect of physical exercise on the treatment of depressive elderly adults has not been investigated thus far in terms of changes in cortical hemispheric activity. The objective of the present study was to identify changes in depressive symptoms, quality of life, and cortical asymmetry produced by aerobic activity. Elderly subjects with a diagnosis of major depressive disorder (DSM-IV) were included. Twenty patients (70% females, 71 +/- 3 years) were divided into an exercise group (pharmacological treatment plus aerobic training) and a control group (undergoing pharmacological treatment) in a quasi-experimental design. Pharmacological treatment was maintained stable throughout the study (antidepressants and anxiolytics). Subjects were evaluated by depression scales (Beck Depression Inventory, Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale) and the Short Form Health Survey-36, and electroencephalographic measurements (frontal and parietal alpha asymmetry) before and after 1 year of treatment. After 1 year, the control group showed a decrease in cortical activity on the right hemisphere (increase of alpha power), which was not observed in the exercise group. The exercise group showed a significant decrease of depressive symptoms, which was not observed in the control group. This result was also accompanied by improved treatment response and remission rate after 1 year of aerobic exercise associated with treatment. This study provides support for the effect of aerobic training on alpha activity and on depressive symptoms in elderly patients. Exercise facilitates the treatment of depressive elderly adults, leading to clinical and physical improvement and protecting against a decrease in cortical activity. PMID:20464340

Deslandes, A C; Moraes, H; Alves, H; Pompeu, F A M S; Silveira, H; Mouta, R; Arcoverde, C; Ribeiro, P; Cagy, M; Piedade, R A M; Laks, J; Coutinho, E S F



EEG source imaging  

Microsoft Academic Search

Objective: Electroencephalography (EEG) is an important tool for studying the temporal dynamics of the human brain's large-scale neuronal circuits. However, most EEG applications fail to capitalize on all of the data's available information, particularly that concerning the location of active sources in the brain. Localizing the sources of a given scalp measurement is only achieved by solving the so-called inverse

Christoph M. Michel; Micah M. Murray; Göran Lantz; Sara Gonzalez; Laurent Spinelli; Rolando Grave de Peralta



A better oscillation detection method robustly extracts EEG rhythms across brain state changes: the human alpha rhythm as a test case.  


Oscillatory activity is a principal mode of operation in the brain. Despite an intense resurgence of interest in the mechanisms and functions of brain rhythms, methods for the detection and analysis of oscillatory activity in neurophysiological recordings are still highly variable across studies. We recently proposed a method for detecting oscillatory activity from time series data, which we call the BOSC (Better OSCillation detection) method. This method produces systematic, objective, and consistent results across frequencies, brain regions and tasks. It does so by modeling the functional form of the background spectrum by fitting the empirically observed spectrum at the recording site. This minimizes bias in oscillation detection across frequency, region and task. Here we show that the method is also robust to dramatic changes in state that are known to influence the shape of the power spectrum, namely, the presence versus absence of the alpha rhythm, and can be applied to independent components, which are thought to reflect underlying sources, in addition to individual raw signals. This suggests that the BOSC method is an effective tool for measuring changes in rhythmic activity in the more common research scenario wherein state is unknown. PMID:20807577

Whitten, Tara A; Hughes, Adam M; Dickson, Clayton T; Caplan, Jeremy B



BOLD Response and EEG Gamma Oscillations  

Microsoft Academic Search

\\u000a The rhythmic activities in the resting or “spontaneous” EEG are usually divided into several frequency bands (delta: <4 Hz;\\u000a theta: 4–8 Hz; alpha: 8–12 Hz; beta: 12–30 Hz; and gamma: 30–70 Hz or higher, centred at 40 Hz), which are associated with\\u000a different behavioural states, ranging from sleep to relaxation, heightened alertness and mental concentration (Lindsley 1952;\\u000a Niedermeyer and Lopes

Gregor Leicht; Christoph S. Herrmann; Christoph Mulert


Resting state cortical rhythms in athletes: A high-resolution EEG study  

Microsoft Academic Search

The present electroencephalographic (EEG) study tested the working hypothesis that the amplitude of resting state cortical EEG rhythms (especially alpha, 8–12Hz) 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

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



Validation of regression-based myogenic correction techniques for scalp and source-localized EEG  

Microsoft Academic Search

EEG and EEG source-estimation are susceptible to electromyographic artifacts (EMG) generated by the cranial muscles. EMG can mask genuine effects or masquerade as a legitimate effectFeven in low frequencies, such as alpha (8-13 Hz). Although regression-based correction has been used previously, only cursory attempts at validation exist, and the utility for source-localized data is unknown. To address this, EEG was

Brenton W. McMenamin; Alexander J. Shackman; Jeffrey S. Maxwell; Lawrence L. Greischar; RICHARD J. DAVIDSONb



Sleep EEG Fingerprints Reveal Accelerated Thalamocortical Oscillatory Dynamics in Williams Syndrome  

ERIC Educational Resources Information Center

|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…

Bodizs, Robert; Gombos, Ferenc; Kovacs, Ilona



Pharmaco-EEG profiles of antidepressants  

PubMed Central

1 Antidepressant drugs produce significant changes in human brain function as reflected in the quantitatively analysed EEG. Two main types of pharmaco-EEG profiles may be differentiated: a thymeretic (desipramine-like) profile characterised mainly by an alpha increase suggesting activating properties and a thymoleptic (imipramine- or amitriptyline-like) profile showing a concomitant increase of slow and fast activities and a decrease in alpha activity indicating also sedative qualities. A small number of compounds exhibit still different profiles. 2 Aside from determining the type of EEG changes, the pharmaco-EEG method seems to be of value in determining time and dose efficacy relations at the target organ, the human brain. Moreover, the relationships between pharmacodynamics and pharmacokinetics may be determined. 3 Fluvoxamine, a selective 5-hydroxytryptamine (5-HT) re-uptake inhibitor from the new class of 2-aminoethyloximethers of aralkylketones, produced a typical thymoleptic pharmaco-EEG profile after oral doses of 75 mg in a double-blind placebo-controlled study involving 10 healthy volunteers. Fluvoxamine (75 mg) induced less augmentation of slow activity than 75 mg imipramine, indicating less sedative properties of fluvoxamine than imipramine. 4 After 75 mg fluvoxamine psychometric tests demonstrated a tendency towards an improvement in attention, concentration, psychomotor activity, after-effect and mood and a significant increase in critical flicker fusion frequency as compared with placebo. Comparison with the reference drug, 75 mg imipramine, revealed a significant superiority of fluvoxamine regarding concentration, psychomotor activity, tapping, reaction time, mood and affectivity. 5 Side-effects (mostly tiredness) were seen in five out of 10 subjects after 75 mg fluvoxamine and in eight out of 10 subjects after 75 mg imipramine. There were no clinically relevant changes in pulse, systolic and diastolic blood pressure.

Saletu, B.; Grunberger, J.; Rajna, P.



EEG findings during special psychical state (Qi Gong state) by means of compressed spectral array and topographic mapping.  


Wallace first reported the changes in EEG during transcendental mediation [6]. Banquet [1] observed, on the basis of spectral analysis of the EEG, that the mediation state was a unique state of consciousness, and separate from wakefulness, drowsiness or sleep. The Qi Gong of China is not the same as either transcendental mediation or the Yoga Gong. The EEG during Qi Gong state is clearly different from those recorded during the resting state. The changes in the EEG during the Qi Gong have not been reported previously. The EEG alpha activity during the Qi Gong state occurs predominantly in the anterior regions. The peak frequency of EEG alpha rhythm is slower than the resting state. The change of EEG during Qi Gong between anterior and posterior half is negative correlation. These changes are statistically significant. PMID:3060312

Zhang, J Z; Zhao, J; He, Q N



EEG: Origin and Measurement  

Microsoft Academic Search

\\u000a The existence of the electrical activity of the brain (i.e. the electroencephalogram or EEG) was discovered more than a century\\u000a ago by Caton. After the demonstration that the EEG could be recorded from the human scalp by Berger in the 1920s, it made\\u000a a slow start before it became accepted as a method of analysis of brain functions in health

Fernando Lopes da Silva


Multilayer perceptron for EEG signal classification during listening to emotional music  

Microsoft Academic Search

In this study an electroencephalography (EEG) signal-based emotion classification algorithm was investigated. Several excerpts of emotional music were used as stimulus for elicitation of emotion-specific EEG signal. Besides, the hemispheric asymmetry alpha power indices of brain activation were extracted as feature vector for training multilayer perceptron classifier (MLP) in order to learn four targeted emotion categories, including joy, angry, sadness,

Yuan-Pin Lin; Chi-Hong Wang; Tien-Lin Wu; Shyh-Kang Jeng; Jyh-Horng Chen



Topographic EEG brain mapping before, during and after Obstructive Sleep Apnea Episodes  

Microsoft Academic Search

Obstructive Sleep Apnea Syndrome (OSAS) is a very common sleep disorder that is associated with several neurocognitive impairments. The present study aims to assess the electroencephalographic (EEG) power before, during and after obstructive apnea episodes, in four frequency bands: delta (?), theta (?), alpha ? and beta (?). For that propose, continuous wavelet transform was applied to the EEG signals

Ana Luisa Coito; David Belo; Teresa Paiva; J. Miguel Sanches



EEG source imaging during two Qigong meditations.  


Experienced Qigong meditators who regularly perform the exercises "Thinking of Nothing" and "Qigong" were studied with multichannel EEG source imaging during their meditations. The intracerebral localization of brain electric activity during the two meditation conditions was compared using sLORETA functional EEG tomography. Differences between conditions were assessed using t statistics (corrected for multiple testing) on the normalized and log-transformed current density values of the sLORETA images. In the EEG alpha-2 frequency, 125 voxels differed significantly; all were more active during "Qigong" than "Thinking of Nothing," forming a single cluster in parietal Brodmann areas 5, 7, 31, and 40, all in the right hemisphere. In the EEG beta-1 frequency, 37 voxels differed significantly; all were more active during "Thinking of Nothing" than "Qigong," forming a single cluster in prefrontal Brodmann areas 6, 8, and 9, all in the left hemisphere. Compared to combined initial-final no-task resting, "Qigong" showed activation in posterior areas whereas "Thinking of Nothing" showed activation in anterior areas. The stronger activity of posterior (right) parietal areas during "Qigong" and anterior (left) prefrontal areas during "Thinking of Nothing" may reflect a predominance of self-reference, attention and input-centered processing in the "Qigong" meditation, and of control-centered processing in the "Thinking of Nothing" meditation. PMID:22562287

Faber, Pascal L; Lehmann, Dietrich; Tei, Shisei; Tsujiuchi, Takuya; Kumano, Hiroaki; Pascual-Marqui, Roberto D; Kochi, Kieko



[Quantitative pharmaco-EEG study of nootropics].  


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 activity gradually decreases. The EEG changes induced by nootropics are the reverse of this process, suggesting the antagonistic efficacy in the geriatric changes. Therefore, quantitative pharmaco-EEG is one of the best tools in the screening for the CNS efficacy of nootropic or anti-dementia substance in the meantime. PMID:2119513

Kinoshita, T



Reductions in qEEG slowing over 1 year and after treatment with Cerebrolysin in patients with moderate–severe traumatic brain injury  

Microsoft Academic Search

Changes in quantitative EEG (qEEG) recordings over a 1-year period and the effects of Cerebrolysin (Cere) on qEEG slowing\\u000a and cognitive performance were investigated in postacute moderate–severe traumatic brain injury (TBI) patients. Time-related\\u000a changes in qEEG activity frequency bands (increases of alpha and beta, and reductions of theta and delta relative power) and\\u000a in qEEG slowing (reduction of EEG power

X. Antón Álvarez; Carolina Sampedro; Jesús Figueroa; Iván Tellado; Andrés González; Manuel García-Fantini; Ramón Cacabelos; Dafin Muresanu; Herbert Moessler



Does EEG montage influence Alzheimer's disease electroclinic diagnosis?  


There is not a specific Alzheimer's disease (AD) diagnostic test. AD diagnosis relies on clinical history, neuropsychological, and laboratory tests, neuroimaging and electroencephalography. Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to measure treatment results. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. The aim of this study was to answer if distinct electrode montages have different sensitivity when differentiating controls from AD patients. We analyzed EEG spectral peaks (delta, theta, alpha, beta, and gamma bands), and we compared references (Biauricular, Longitudinal bipolar, Crossed bipolar, Counterpart bipolar, and Cz reference). Support Vector Machines and Logistic Regression classifiers showed Counterpart bipolar montage as the most sensitive electrode combination. Our results suggest that Counterpart bipolar montage is the best choice to study EEG spectral peaks of controls versus AD. PMID:21629711

Trambaiolli, L R; Lorena, A C; Fraga, F J; Kanda, P A M K; Nitrini, R; Anghinah, R



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

PubMed Central

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

Stevens, J R; Livermore, A



Effect of Low-Level Laser Stimulation on EEG  

PubMed Central

Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG) changes is not known. We designed a low-level laser array stimulator (6?pcs laser diode, wavelength 830?nm, output power 7?mW, and operation frequency 10?Hz) to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

Wu, Jih-Huah; Chang, Wen-Dien; Hsieh, Chang-Wei; Jiang, Joe-Air; Fang, Wei; Shan, Yi-Chia; Chang, Yang-Chyuan



Event-related EEG time-frequency analysis and the Orienting Reflex to auditory stimuli.  


Sokolov's classic works discussed electroencephalogram (EEG) alpha desynchronization as a measure of the Orienting Reflex (OR). Early studies confirmed that this reduced with repeated auditory stimulation, but without reliable stimulus-significance effects. We presented an auditory habituation series with counterbalanced indifferent and significant (counting) instructions. Time-frequency analysis of electrooculogram (EOG)-corrected EEG was used to explore prestimulus levels and the timing and amplitude of event-related increases and decreases in 4 classic EEG bands. Decrement over trials and response recovery were substantial for the transient increase (in delta, theta, and alpha) and subsequent desynchronization (in theta, alpha, and beta). There was little evidence of dishabituation and few effects of counting. Expected effects in stimulus-induced alpha desynchronization were confirmed. Two EEG response patterns over trials and conditions, distinct from the full OR pattern, warrant further research. PMID:22524168

Barry, Robert J; Steiner, Genevieve Z; De Blasio, Frances M



Ultradian rhythms of alternating cerebral hemispheric EEG dominance are coupled to rapid eye movement and non-rapid eye movement stage 4 sleep in humans  

Microsoft Academic Search

Objective: To replicate the left minus right (L?R) hemisphere EEG power shifts coupled to rapid eye movement (REM) and non-rapid eye movement (NREM) sleep observed in 1972 by Goldstein (Physiol Behav (1972) 811), and to characterize the L?R EEG power spectra for total EEG, delta, theta, alpha and beta bands.Background: Ultradian alternating cerebral hemispheric dominance rhythms are observed using EEG

David S Shannahoff-Khalsa; J. Christian Gillin; F. Eugene Yates; Arlene Schlosser; Eugene M Zawadzki



Hereditary fibrinogen A alpha-chain amyloidosis: phenotypic characterization of a systemic disease and the role of liver transplantation.  


Variants of fibrinogen A alpha-chain (AFib) cause the most common type of hereditary renal amyloidosis in Europe and, possibly, the United States as well. Variant fibrinogen is produced in the liver, and solitary renal allografts fail within 1 to 7 years with recurrent amyloidosis. We assessed 22 AFib patients for combined liver and kidney transplantation (LKT) and report the clinical features and outcome. Twenty-one had E526V and 1, the R554L variant. Coronary atherosclerosis was identified in 68% and systemic atheromatosis in 55%. Vascular atheroma excised at endarterectomy and endomyocardial biopsies contained purely variant fibrinogen amyloid. Half had autonomic neuropathy. Six of 9 patients who underwent LKT are alive (67%), with good allograft function and no amyloidosis at median 67 months (range, 33-155 months) of follow-up. Serial technetium-99m-labeled dimercaptosuccinic acid ((99m)Tc-DMSA) renal scintigraphy in 2 cases of preemptive LKT demonstrated preserved native kidney residual function at 5 years. Four explanted livers were used successfully for domino transplantation. Fibrinogen amyloidosis is a systemic amyloid disease with visceral, vascular, cardiac, and neurologic involvement. LKT is curative; however, cardiovascular amyloidosis may preclude this option. Our data encourage evaluation of preemptive solitary liver transplantation early in the course of amyloid nephropathy to prevent hemodialysis and kidney transplantation. PMID:19633201

Stangou, Arie J; Banner, Nicholas R; Hendry, Bruce M; Rela, Mohamed; Portmann, Bernard; Wendon, Julia; Monaghan, Mark; Maccarthy, Philip; Buxton-Thomas, Muriel; Mathias, Christopher J; Liepnieks, Juris J; O'Grady, John; Heaton, Nigel D; Benson, Merrill D



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

PubMed Central

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.

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



Caffeine antagonizes EEG effects of tobacco withdrawal.  


Six current cigarette smokers and coffee drinkers were given combinations of 0, 150, or 300 mg caffeine and 0, 2, or 4 mg nicotine polacrilex following 12-h nicotine and caffeine abstinence. On one study day, subjects were allowed to smoke cigarettes and to drink caffeinated beverages and no drugs were given. Tobacco and caffeine abstinence impaired performance on the serial addition/subtraction and digit recall tasks; decreased scores on the MBG scale and ratings of "clear-headed" and "quick-witted"; and increased ratings of "irritability," "muscular tension," "headache," "drowsy," "clumsy," "feeble," and "dreamy." The deprivation caused characteristic EEG signs of nicotine withdrawal including increased theta power and decreased alpha frequency. These EEG effects were reversed by cigarette smoking and caffeine administration, but nicotine polacrilex was less effective. Deprivation-induced performance and subjective measures were not changed by administration of nicotine and caffeine combinations. PMID:8029263

Cohen, C; Pickworth, W B; Bunker, E B; Henningfield, J E



Transcriptional regulation of the alpha-1 type II collagen gene by nuclear factor ?B/p65 and Sox9 in the chondrocytic phenotype of uterine carcinosarcomas.  


Uterine carcinosarcomas (U-CSs) are considered monoclonal in origin, but little is known about the mechanisms for establishment of heterologous sarcomatous components. Here, we examine the functional roles of nuclear factor ?B (NF-?B)/p65 and Sox9 in the transcriptional regulation of alpha-1 type II collagen (COL2A1), a hallmark of chondrogenesis, during morphologic change in the direction of the chondrocytic phenotype. In 32 cases of U-CS, both phosphorylated p65 and Sox9 expression were colocalized in Col2A1-positive sarcomatous components, particularly in cartilaginous elements, with strongly positive correlation (? = 0.72, P = .005). A positive association of Col2A1 expression between protein (immunohistochemistry) and messenger RNA (in situ hybridization) assays was evident in sarcomatous components, whereas 9 cases also showed distinct positive signals for the messenger RNA without protein expression in carcinomatous elements, probably through a posttranscriptional and/or posttranslational modulation mechanism. In the Ishikawa endometrial cancer line, overexpression of p65 could activate transcription of COL2A1 promoter-intron reporters through binding to specific NF-?B sites in the first intron, along with up-regulation of Sox9. Exogenous induction of Sox9 also caused an increase in transcription of COL2A1, in contrast to a repression of the p65-mediated COL2A1 transcription, suggesting the existence of a negative feedback loop. These data, therefore, suggest that NF-?B/p65 signaling, as well as Sox9, may contribute to changes in the morphology of U-CS cells toward the chondrocytic phenotype through modulation of COL2A1 transcription. PMID:23618358

Yoshida, Tsutomu; Hashimura, Miki; Kuwata, Takeshi; Matsumoto, Toshihide; Suzuki, Erina; Tazo, Yuki; Nakajima, Hiroyasu; Inukai, Madoka; Saegusa, Makoto



Response of hepatitis C virus to long-term passage in the presence of alpha interferon: multiple mutations and a common phenotype.  


Cell culture-produced hepatitis C virus (HCV) has been subjected to up to 100 serial passages in human hepatoma cells in the absence or presence of different doses of alpha interferon (IFN-?). Virus survival, genetic changes, fitness levels, and phenotypic traits have been examined. While high initial IFN-? doses (increasing from 1 to 4 IU/ml) did not allow HCV survival beyond passage 40, a gradual exposure (from 0.25 to 10 IU/ml) allowed the virus to survive for at least 100 passages. The virus passaged in the presence of IFN-? acquired IFN-? resistance as evidenced by enhanced progeny production and viral protein expression in an IFN-? environment. A partial IFN-? resistance was also noted in populations passaged in the absence of IFN-?. All lineages acquired adaptative mutations, and multiple, nonsynonymous mutations scattered throughout the genome were present in IFN-?-selected populations. Comparison of consensus sequences indicates a dominance of synonymous versus nonsynonymous substitutions. IFN-?-resistant populations displayed decreased sensitivity to a combination of IFN-? and ribavirin. A phenotypic trait common to all assayed viral populations is the ability to increase shutoff host cell protein synthesis, accentuated in infections with IFN-?-selected populations carried out in the presence of IFN-?. The trait was associated with enhanced phosphorylation of protein kinase R (PKR) and eIF2?, although other contributing factors are likely. The results suggest that multiple, independent mutational pathways can confer IFN-? resistance to HCV and might explain why no unified picture has been obtained regarding IFN-? resistance in vivo. PMID:23637397

Perales, Celia; Beach, Nathan M; Gallego, Isabel; Soria, Maria Eugenia; Quer, Josep; Esteban, Juan Ignacio; Rice, Charles; Domingo, Esteban; Sheldon, Julie



A forty-five year follow-up EEG study of Qigong practice.  


A follow-up EEG study was conducted on a subject with 50 years of experiences in Qigong. Resting EEG at present showed frontally dominant alpha-1 as compared to occipitally dominant alpha-2 described in 1962. During the Qigong practice alph-1 enhanced quickly and became far more prominent than 50 years ago. Compared with baseline, these activities remained to be higher at rest after the Qigong practice. These results suggest that extended practice in meditation may change the EEG pattern and its underlying neurophysiology. It remains to be explored as to what biological significance and clinical relevance do these physiological changes might mean. PMID:19229721

Qin, Zhen; Jin, Yi; Lin, Shin; Hermanowicz, Neal S



Integrated system for analysis and automatic classification of sleep EEG  

Microsoft Academic Search

In this paper we describe a system for automatic all night sleep analysis, based on neural networks. In what concerns sleep staging, the system consists of a three-step analysis. The first step is the recognition of elementary patterns in EEG (delta, alpha, spindle and K complex waves), EOG and EMG, and spectral analysis for background activity. The second step is

Osvaldo Rocha Pacheco; Francisco Vaz



Interobserver variability in EEG interpretation.  


A random sample of 100 active electroencephalographers in the United States evaluated 10-second samples of 12 selected EEGs. The evaluations consisted of multiple-choice questions related to the age of the patient, EEG finding, artifact, and consciousness of the patient. The rate of reporting the "correct" response was examined in terms of various respondent characteristics such as EEG board certification, age, percent of time in clinical EEG work, and number of recordings interpreted annually. This study indicates that, even today, there is considerable variability in EEG interpretation, and that this variability is influenced by specific reader characteristics. PMID:4069362

Williams, G W; Lüders, H O; Brickner, A; Goormastic, M; Klass, D W



Correlation of a missense mutation in the human Secretor alpha 1,2-fucosyltransferase gene with the Lewis(a+b+) phenotype: a potential molecular basis for the weak Secretor allele (Sew).  

PubMed Central

A missense mutation (A385 to T), predicting an Ile129 to Phe substitution, in the human Secretor alpha 1,2-fucosyltransferase gene was present in double dose in Lewis(a+b+) individuals, but not in Lewis(a-b+) individuals. Co-segregation of the Lewis(a+b+) phenotype with homozygosity for the mutation was also verified. These results yield a potential molecular basis for the weak Secretor allele (Sew) accounting for the Lewis(a+b+) phenotype. Images Figure 2 Figure 3

Yu, L C; Yang, Y H; Broadberry, R E; Chen, Y H; Chan, Y S; Lin, M



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

Microsoft Academic Search

This study investigated the differences in cognitive processes related to creativity and intelligence using EEG coherence and power measures in the lower (?1=7.9–10.0 Hz) and upper alpha band (?2=10.1–12.9 Hz). In two experiments, gifted, creative, intelligent subjects, and individuals of average ability solved closed and open problems while their EEG was recorded. The analysis of EEG measures in Experiment 1

Norbert Jaušovec



Phenotypic modulation of keratins, vimentin, and alpha-fetoprotein in cultured rat liver epithelial cells after chemical, oncogene, and spontaneous transformation.  


Several lines of evidence have indicated that rat liver epithelial (RLE) cell lines may be related to a dormant stem cell compartment in the liver in vivo. We have demonstrated that keratin 14 (K14) is expressed together with vimentin in undifferentiated RLE cells. However, upon spontaneous transformation and differentiation to hepatoblast-like progeny the expression of these intermediate filaments (IF) is abrogated, while expression of another set of genes, among others keratin 18 (K18) and alpha-fetoprotein (AFP), is induced (Bisgaard et al., 1994, J. Cell. Physiol., in press). To better understand the mechanisms underlying IF expression during transformation and differentiation of RLE cells we examined the expression and regulation of IFs in clonal cell lines of chemically, oncogene, and spontaneously transformed RLE cells and their resulting tumors. These clonal lines provided a wide variety of tumor phenotypes including trabecular, solid and tubular adenocarcinomas, undifferentiated carcinomas, and spindle cell carcinomas. Northern blot analysis of the cell lines confirmed the differential expression of IF mRNAs. While keratin 8 (K8) was expressed at similar steady-state levels in all cell lines, K14 and vimentin but not K18 were expressed in the majority of cell lines chemically transformed with aflatoxin B1 or by transduction of oncogenes. In contrast, cell lines transformed spontaneously by prolonged passage in vitro expressed K18, while K14 and vimentin were absent. The keratin expression pattern in vitro was retained in the majority of the resulting tumors. However, the keratins expressed in vitro did not accurately predict the tumor phenotype in vivo. In particular, in tumors typed morphologically as adenocarcinomas, the keratin pair typically expressed in chemically transformed tumor cells was K8/K14, whereas K8/K18 was expressed in the tumors derived from spontaneously transformed cell lines. Finally we showed by nuclear run-on and in vitro translation analyses that the expression of K14, K18, and vimentin in transformed RLE cell lines was regulated at the transcriptional level, whereas that of K8 appeared to be posttranslational. These findings suggest that events controlling the differential expression of IF genes are involved in the processes leading to transformation and differentiation of the RLE cell lines. We conclude that the transformed RLE cell lines provide a valuable model to further examine the regulatory mechanisms involved in hepatic differentiation of undifferentiated "progenitor-like" RLE cells. PMID:7514612

Bisgaard, H C; Ton, P T; Nagy, P; Thorgeirsson, S S



Unusual EEG patterns in coma, and their evolution.  

PubMed Central

A 23-year-old chronic asthmatic patient is reported who showed successively four different EEG patterns within a 7 day period of unconsciousness following cardio-respiratory arrest. The initial record was dominated by alpha activity, then beta activity supervened, to be followed by spindle components. Finally an isoelectric tracing occurred before death. A computer file search for all cases of unusual EEG coma patterns was carried out. It failed to reveal any other patient with a similar sequence, but various types of evolution were noted. Such features are seen in only a very small percentage of comatose patients, and in the context of cardio-respiratory arrest are almost invariably fatal.

Scott, D F; Sumra, R S



Human T-cell receptor (TCR) alpha/beta + CD4-CD8- T cells express oligoclonal TCRs, share junctional motifs across TCR V beta-gene families, and phenotypically resemble memory T cells.  

PubMed Central

Most human T cells express the TCR alpha/beta and either CD4 or CD8 molecules (single positive, SP); however, small numbers lack CD4 and CD8. In inbred mice, alpha/beta CD4-CD8- (double negative, DN) T cells preferentially express certain beta variable region (V beta) families and may arise via unique developmental pathways. Increased percentages of alpha/beta DN T cells have been identified in some human and murine autoimmune and immunodeficiency diseases. However, their contribution to disease pathology or normal immunity is unknown. To study the cell surface phenotype and TCR diversity of human alpha/beta DN T cells, these cells were isolated from the peripheral blood of healthy adults. The proportion of alpha/beta DN T cells expressing molecules associated with activation (HLA-DR), previous exposure to antigen (CD45RO), and cytotoxic function (CD56, CD57, and CD11b) was increased relative to SP T cells. The TCR V beta repertoire of alpha/beta DN T cells was different from that of alpha/beta SP T cells, although most major gene families were present. For example, higher proportions of V beta 11, a minor gene family in peripheral blood leukocytes, were found in most alpha/beta DN T-cell samples. In contrast to mice, no dominant V beta family was used consistently in different human individuals. Within an individual alpha/beta DN T cells possessed an oligoclonal TCR beta repertoire with conservation of several distinct junctional amino acid motifs with one joined to three different V beta genes in two individuals, suggesting that these cells have undergone a selection process driven by a limited set of ligands. The possibility that they may represent, at least in part, originally SP T cells anergized by down-modulation of CD4 or CD8 must also be entertained. Overall, this study demonstrates that human peripheral blood alpha/beta DN T cells possess unique phenotypic and TCR beta repertoire characteristics when compared with the major alpha/beta SP T cell populations and thus may serve specialized immunologic functions and/or have an unusual origin. Images Fig. 4

Brooks, E G; Balk, S P; Aupeix, K; Colonna, M; Strominger, J L; Groh-Spies, V



Atypical Alpha Asymmetry in Adults with ADHD  

ERIC Educational Resources Information Center

|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

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



EEG analyses with SOBI.  

SciTech Connect

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.

Glickman, Matthew R.; Tang, Akaysha (University of New Mexico, Albuquerque, NM)



EEG based home lighting system  

Microsoft Academic Search

This paper describes the EEG based home lighting system that uses voluntary eye blinks extracted from EEG signals to activate the lighting system. The system comprises of a PIC16F877A microcontroller and a lighting circuit. The EEG signals were first filtered to remove artifacts and then passed through the microcontroller which detected the four-second eye blinks using peak detection method. Once

N. Wahy; W. Mansor



Investigation on visual evoked response driven by sine modulated light and alpha feedback rhythm  

Microsoft Academic Search

An investigation of sine-modulated light (SML) as a stimulus for visual evoked responses and alpha rhythm feedback (ARF) is reported. The development of a multifunctional EEG research system (EEGRS) and EEG information analysis and management system (EIAMS) and eight experiments on SML and ARF are discussed. The EEGRS consists of a programmable, multifunctional, dual-channel stimulus generator, a transducer, an EEG

Lin Qi; Zhang Zuoseng



Decreased EEG synchronization in Alzheimer's disease and mild cognitive impairment.  


The hypothesis of a functional disconnection of neuro-cognitive networks in patients with mild cognitive impairment (MCI) and Alzheimer Dementia was investigated using baseline resting EEG data. EEG databases from New York (264 subjects) and Stockholm (155 subjects), including healthy controls and patients with varying degrees of cognitive decline or Alzheimer Dementia were analyzed using Global Field Synchronization (GFS), a novel measure of global EEG synchronization. GFS reflects the global amount of phase-locked activity at a given frequency by a single number; it is independent of the recording reference and of implicit source models. Patients showed decreased GFS values in Alpha, Beta, and Gamma frequency bands, and increased GFS values in the Delta band, confirming the hypothesized disconnection syndrome. The results are discussed within the framework of current knowledge about the functional significance of the affected frequency bands. PMID:15582746

Koenig, T; Prichep, L; Dierks, T; Hubl, D; Wahlund, L O; John, E R; Jelic, V



[EEG in mathematical logical problem solving].  


The model of mathematical logic tasks was developed at which decision there was a value coherence in delta-range raised. In low-frequency ranges (delta, theta, and alpha) a coherence of potentials of frontal cortex were increased. In high-frequency ranges (beta1, beta2, gamma) in frontal cortex coherence was decreased, and its increasing in central, parietal, temporal, and occipital areas with prevalence in the left hemisphere. Most changes of quantity of positive connections observed in value diagonal coherence. Analysis of spectral power EEG has shown, that at the decision of tasks there is a generalised raising on a cortex in delta-range. Theta-activity increased in a frontal cortex, and gamma band was raised in occipital areas. A spectral power in an alpha range mainly decreased. PMID:21260977

Pavlygina, R A; Davydov, V I; Sakaharov, D S; Tutushkina, M V; Priamonosova, A A


Respiratory Cycle-Related EEG Changes: Response to CPAP  

PubMed Central

Study Objectives: Respiratory cycle-related EEG changes (RCREC) quantify statistically significant synchrony between respiratory cycles and EEG spectral power, vary to some extent with work of breathing, and may help to predict sleepiness in patients with obstructive sleep apnea. This study was designed to assess the acute response of RCREC to relief of upper airway obstruction by positive airway pressure (PAP). Design: Comparison of RCREC between baseline diagnostic polysomnograms and PAP titration studies. Setting: Accredited academic sleep disorders center. Patients: Fifty adults referred for suspected sleep disordered breathing. Interventions: For each recording, the RCREC in specific physiologic EEG frequency ranges were computed as previously described for the last 3 h of sleep not occupied by apneic events. Results: The sample included 27 women; mean age was 47 ± 11 (SD) years; and median respiratory disturbance index at baseline was 24 (inter-quartile range 15-43). Decrements in RCREC, from baseline to PAP titration, reached 43%, 24%, 14%, 22%, and 31% for delta (P = 0.0004), theta (P = 0.01), alpha (P = 0.10), sigma (P = 0.08), and beta (P = 0.01) EEG frequency ranges, respectively. Within each specific sleep stage, these reductions from baseline to PAP studies in synchrony between EEG power and respiratory cycles still reached significance (P < 0.05) for one or more EEG frequency ranges and for all frequency ranges during REM sleep. Conclusions: RCREC tends to diminish acutely with alleviation of upper airway obstruction by PAP. These data in combination with previous observations support the hypothesis that RCREC reflect numerous, subtle, brief, but consequential inspiratory microarousals. Citation: Chervin RD; Shelgikar AV; Burns JW. Respiratory cycle-related EEG changes: response to CPAP. SLEEP 2012;35(2):203-209.

Chervin, Ronald D.; Shelgikar, Anita Valanju; Burns, Joseph W.



Development of the EEG of school-age children and adolescents II. Topography  

Microsoft Academic Search

Summary Topographic aspects of EEG development of normal children and adolescents from 6 to 17 years are investigated with respect to various spectral parameters. The topographic distribution of spectral band power does not change between hemispheres across age. Changes take place, however, in the antero-posterior dimension. For the bands theta, alpha 1 and alpha 2 (and less so for delta)

Theo Gasser; Christine Jennen-Steinmetz; Lothar Sroka; Rolf Verleger; J MOCKS



EEG Studies with Young Children.  

ERIC Educational Resources Information Center

|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…

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



A pilot study to evaluate the effects of Cerebrolysin on cognition and qEEG in vascular dementia: cognitive improvement correlates with qEEG acceleration.  


The effects of the neurotrophic compound Cerebrolysin (Cere) on cognitive performance, evaluated with the ADAS-cog, and on qEEG activity were investigated in forty one patients with mild to moderate severe probable vascular dementia (VaD) according to NINDS-AIREN criteria, included in a placebo-controlled pilot study. Patients received i.v. infusions of Cere (10 or 30 ml) or placebo (normal saline) 5 days/week for 4 weeks. Mean score of change from baseline in the ADAS-cog and percent change from baseline in slow to fast EEG power ratio (PR) scores were the two primary endpoints. Correlations between cognition and qEEG were also evaluated for both baseline scores and for scores of change from baseline in ADAS-cog and in qEEG parameters, including EEG power ratio (PR) as an index of EEG slowing. Baseline ADAS-cog scores showed significant positive correlations with delta power, theta power and PR scores, and correlated negatively with alpha activity. These correlations indicating that an increased EEG slowing is associated with a worst cognitive performance in VaD patients. Cere treatment improved cognitive performance significantly at the 10 ml dose and reduced EEG slowing with both 10 and 30 ml dosages. A significant positive correlation between PR and ADAS-cog scores of change from baseline was observed in Cere-treated patients. According to results of this pilot study, it is concluded that Cere improves cognitive performance and reduces EEG slowing in patients with VaD, and that there is a positive relationship between changes in cognition and qEEG activity induced by Cere. The conduction of further regular clinical trials is required to confirm the potential utility of Cere in the treatment of VaD suggested by the present results. PMID:18048059

Muresanu, Dafin F; Alvarez, X Anton; Moessler, Herbert; Buia, Manuel; Stan, Adina; Pintea, Daniela; Moldovan, Florina; Popescu, Bogdan O



Topographic EEG Brain Mapping before, during and after Obstructive Sleep Apnea Episodes  

Microsoft Academic Search

\\u000a Obstructive Sleep Apnea Syndrome (OSAS) is a very common sleep disorder that is associated with several neurocognitive impairments.\\u000a The present study aims to assess the electroencephalographic (EEG) power before, during and after obstructive apnea episodes,\\u000a in four frequency bands: delta (?), theta (?), alpha (?) and beta (?). For that purpose, continuous wavelet transform was applied to the EEG signals

David Belo; Ana Coito; Teresa Paiva; João Sanches


Growth spurts in brain maturation during middle childhood as indexed by EEG power spectra  

Microsoft Academic Search

Developmental changes in background EEG power spectra were examined in 5–12-year-old children. The results confirmed older and more recent studies that reported continuous maturation and more sudden growth spurts in power spectral amplitude. EEG power in the Delta and Theta frequency bands decreased gradually with age, while power in the Alpha and Beta bands changed very little. Changes in spectral

Riek J. M. Somsen; Ben J. van't Klooster; Maurits W. van der Molen; Harry M. P. van Leeuwen; Rob Licht



Distinct Transient Outward Potassium Current (Ito) Phenotypes and Distribution of Fast-inactivating Potassium Channel Alpha Subunits in Ferret Left Ventricular Myocytes  

Microsoft Academic Search

The biophysical characteristics and a subunits underlying calcium-independent transient outward potassium current (I to ) phenotypes expressed in ferret left ventricular epicardial (LV epi) and endocardial (LV endo) myocytes were analyzed using patch clamp, fluorescent in situ hybridization (FISH), and immunofluores- cent (IF) techniques. Two distinct I to phenotypes were measured (21-22 8 C) in the majority of LV epi

Mulugu V. Brahmajothi; Donald L. Campbell; Randall L. Rasmusson; Michael J. Morales; James S. Trimmer; Jeanne M. Nerbonne; Harold C. Strauss



Electroencephalogram alpha (8–15 Hz) responses to visual stimuli in cat cortex, thalamus, and hippocampus: a distributed alpha network?  

Microsoft Academic Search

To investigate possible functional correlates of alpha (8–15 Hz) oscillations in the electroencephalogram (EEG) intracranial recordings in cats (from thalamus, occipital cortex, and hippocampus) were performed. In response to visual stimuli, event-related alpha oscillations were observed. Such alpha responses were found not only in a specific sensory (visual) pathway but also in the hippocampus, hinting at a possible distributed alpha

Martin Schürmann; Tamer Demiralp; Erol Ba?ar; Canan Ba?ar Eroglu



EEG from a single-channel dry-sensor recording device.  


While a laboratory setting and research-grade electroencephalogram (EEG) equipment allow control of variables and high-quality multiple-channel EEG recording, there are situations and populations for which this is not suitable. The present studies examined the validity of a new method of single-channel EEG measurement that is portable and uses dry-sensor technology. In study 1, EEG was recorded simultaneously from the portable device and 4 standard EEG electrodes from a research system, during eyes open (EO) and eyes closed (EC) resting conditions, with 20 adult participants. Average correlations with the research system frequency spectra were highest at site F3 for portable device data processed onboard of the device (r = .90), and for device data processed in a standard manner (r = .89). Further, predictable variations in EO versus EC comparisons were observed. In study 2, twenty-three healthy children had EEGs recorded from the portable device during EO and EC resting conditions, and 3 EO active conditions (ie, relaxation, attention, and cognitive load). Absolute and relative EEG band power differed between conditions in predicted ways, including a reduction in relative theta power and an increase in relative alpha power in EC compared to EO resting conditions. Overall, the results suggest that, while limited in terms of scalp recording locations, the portable device has potential utility in certain EEG recording situations where ease of use is a priority. PMID:22715485

Johnstone, Stuart J; Blackman, Russell; Bruggemann, Jason M



Human EEG dimensionality and depth of anesthesia  

Microsoft Academic Search

Although the brain is the target organ of anesthesia, the electroencephalogram (EEG) is not routinely monitored during anesthetic procedures. This is due primarily to the difficulty of interpreting changes in the complex EEG waveform with respect to anesthetic conditions. Most attempts at developing EEG derived variables have been based on spectral analysis. In this study the EEG is examined as

Richard C. Watt; Christina L. Springfield; E. S. Maslana; Amel Kanemoto; Kenneth Mylrea



T-Cell alpha beta + and gamma delta + Deficient Mice Display Abnormal but Distinct Phenotypes toward a Natural, Widespread Infection of the Intestinal Epithelium  

Microsoft Academic Search

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

Scott J. Roberts; Adrian L. Smith; A. Brian West; Li Wen; R. Craig Findly; Michael J. Owen; Adrian C. Hayday



21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.  

Code of Federal Regulations, 2013 CFR

...false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882...1855 Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of...



21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.  

Code of Federal Regulations, 2010 CFR

...false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882...1855 Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of...



21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.  

Code of Federal Regulations, 2010 CFR

...false Electroencephalogram (EEG) telemetry system. 882.1855 Section 882...1855 Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of...



21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.  

Code of Federal Regulations, 2013 CFR

...Electroencephalogram (EEG) signal spectrum analyzer. 882.1420 Section...Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification...electroencephalogram (EEG) signal spectrum analyzer is a device used to...



[Quantitative and topographic EEG brain mapping: a study of normal adult population].  


We studied the electric brain activity during wakefulness in 20 Brazilian people through digital EEG and spectral analysis in order to propose a standardization for Brazilian adult population. All this group is healthy with laboratory examinations and mini-mental state (scores higher than 27) evaluation normal. After Fourier fast transformation (FFT) calculation, we found a histogram display with monomodal distribution, with higher values in alpha band. Analyzing the average of these results, different standards from the analogical traditional EEG were found, as the distribution of alpha band and delta activity behavior. The beta 2 and beta 3 behavior showed a diffuse distribution, that is not the usual. By the other hand, other findings are congruent to the analogical EEG as the alpha posterior predominance and the bigger presence of theta activity at the central regions. PMID:9686121

Anghinah, R; Kanda, P A; Jorge, M S; Melo, A C



Development of an experimental portable electroencephalograph (case study: Alpha wave detector)  

Microsoft Academic Search

This paper describes the development of an electroencephalograph (EEG device) with portable application possibilities. The hardware design is based on the ModularEEG. It is redeveloped mainly to run from 3 V batteries and consume less power. The developed firmware detects the alpha brainwave without using any computer (PC). It uses signal correlation and windowing technique to detect the alpha frequency

Ary Setijadi; Ori Novanda; Tati L. R. Mengko



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


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

Propping, P



EEG during masturbation and ejaculation  

Microsoft Academic Search

The occurrence of a distinctive EEG pattern specifically related to sexual arousal and orgasm would provide a reliable and convenient means of identifying such events in the laboratory and would also provide clues to cerebral structures involved in the processes.

Benjamin Graber; John W. Rohrbaugh; David B. Newlin; Jerald L. Varner; Robert J. Ellingson



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


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 idiopathic epilepsies. PMID:8833159

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



[The EEG correlates of delayed mental development in adolescents].  


Fifty-eight male adolescents aged 15-17 years have been divided into 3 groups: 31 patients with mental infantilism syndrome were included in the study group, 14 with organic brain disorders--in the comparison group and 13 psychiatrically and neurologically normal subjects--in the control group. EEG was recorded from 12 leads monopolarly at rest, during hemisphere-specific cognitive tasks performance and exposure to aversive sound stimulation. Two-Hz wide EEG spectral ranges--A, theta1, theta2, alpha1 and alpha2--were analyzed. Only in the study group, there were decreased values of alpha2 spectral power (SP) and reduced reactivity to functional tests and insufficient lateral differentiation of the reactions during the cognitive tasks performance. Maximal deviation of the SP reactivity indices as compared to the comparison group was found in alpha2 range. The disturbances obtained indicate the delay of brain maturation and retardation in formation of specific neural networks. The results of the study demonstrate that indices of alpha2 SP may be considered as objective criteria of delayed mental maturation. PMID:16252384

Dmitrieva, T B; Kirenskaia, A V; Lar'kina, E G; Lavrova, T N; Makushkin, E V



High temporal resolution dynamic mapping of instantaneous EEG amplitude modulation after tone-burst auditory stimulation.  


A new method of instantaneous EEG analysis based on amplitude modulation (AM-EEG) was applied to analyze the AM-EEG changes in the alpha frequency band (8.20-12.89 Hz) for successive 5 ms epochs. Repeated auditory tone-burst stimuli (of 220 ms duration) were presented at fixed 2.56 second intervals to 12 attending right-handed young female volunteers, who were EEG-recorded over 19 EEG channels at 200 Hz sampling frequency. The time-course of functional activation was characterized in terms of percent decrease in instantaneous amplitude modulation, as compared to baseline, in analogy with the classical event-related desynchronization paradigm. A dynamic sequence of the successive 122 AM-EEG maps obtained for the 610 ms from beginning of tone-burst was stored and later animated on PC microcomputer. Topological changes among successive maps were extracted into 40 specific AM-EEG maps. Early left temporal and centro-temporal activation was observed, followed first by strong bilateral frontal, and then by left temporal activation. These changes induced by a warning tone-burst are discussed in terms of functional neurophysiology. The present method therefore allows an improved time-resolution for functional brain activation paradigms. PMID:10642012

Etévenon, P; Lebrun, N; Clochon, P; Perchey, G; Eustache, F; Baron, J C



Insecure attachment is associated with the ?-EEG anomaly during sleep  

PubMed Central

Background The ?-EEG anomaly during sleep, originally associated with chronic pain, is noted in several psychiatric and medical conditions and is also present in some normal subjects. The exact significance of the ?-EEG anomaly is uncertain, but it has been suggested to be a nonspecific response to a variety of noxious stimuli. We propose that attachment insecurity, which is often associated with a state of hypervigilance during wakefulness, may be associated with the ?-EEG anomaly during sleep. Methods Thirty one consecutive patients referred to a Sleep Disorders Clinic for clinical assessment of sleep complaints underwent standard polysomnographic recording. The degree of alpha activity in polysomnographs was scored visually according to standard criteria. Attachment insecurity was measured with the Experience in Close Relationships – Revised questionnaire. Results Attachment anxiety was significantly associated with the proportion of sleep in which ? waves were present (df = 1, F = 5.01, p = 0.03). The relationship between the ?-EEG anomaly and attachment anxiety was not explained by the distribution of sleep and mood diagnoses, medications, anxiety symptoms or depression symptoms. Conclusion Interpersonal style in close relationships may be related to sleep physiology. Further research to determine the nature of the relationship between attachment, sleep and other factors that are related to each of these, such as a history of personal adversity, is warranted.

Sloan, Eileen P; Maunder, Robert G; Hunter, Jonathan J; Moldofsky, Harvey



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


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

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



Optimizing microsurgical skills with EEG neurofeedback  

PubMed Central

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 total surgery time, despite suboptimal training efficacies. Overall, the data set provides encouraging evidence of optimised learning of a complex medical specialty via neurofeedback training.

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



Alpha oscillations in brain functioning: an integrative theory  

Microsoft Academic Search

The old concept stating that EEG alpha (10-Hz) activity reflects passive or idling states of the brain is giving way to modern views of 10-Hz oscillations in relation to diverse brain functions comprising sensory, motor, and memory processes: (1) Spontaneous alpha activity is not pure noise as shown by methods of chaos analysis. (2) Evoked alpha oscillations patterns (precisely time-locked

E. Basar; M. Schurmann; C. Basar-eroglu; S. Karakas



Therapeutic effects of individualized alpha frequency transcranial magnetic stimulation (alphaTMS) on the negative symptoms of schizophrenia  

Microsoft Academic Search

Previous research in clinical electroencephalography (EEG) has demonstrated that reduction of alpha frequency (8-13 Hz) EEG activity may have particular relevance to the negative symptoms of schizophrenia. Repetitive Trans- cranial Magnetic Stimulation (rTMS) was utilized to inves- tigate this relationship by assessing the therapeutic effects of stimulation set individually at each subject's peak alpha frequency (aTMS). Twenty-seven subjects, with predomi-

Yi Jin; Steven G. Potkin; A. S. Kemp; Steven T. Huerta; Gustavo Alva; Trung Minh Thai; Danilo Carreon; William E. Bunney



Motion-related artefacts in EEG predict neuronally plausible patterns of activation in fMRI data.  


The simultaneous acquisition and subsequent analysis of EEG and fMRI data is challenging owing to increased noise levels in the EEG data. A common method to integrate data from these two modalities is to use aspects of the EEG data, such as the amplitudes of event-related potentials (ERP) or oscillatory EEG activity, to predict fluctuations in the fMRI data. However, this relies on the acquisition of high quality datasets to ensure that only the correlates of neuronal activity are being studied. In this study, we investigate the effects of head-motion-related artefacts in the EEG signal on the predicted T2*-weighted signal variation. We apply our analyses to two independent datasets: 1) four participants were asked to move their feet in the scanner to generate small head movements, and 2) four participants performed an episodic memory task. We created T2*-weighted signal predictors from indicators of abrupt head motion using derivatives of the realignment parameters, from visually detected artefacts in the EEG as well as from three EEG frequency bands (theta, alpha and beta). In both datasets, we found little correlation between the T2*-weighted signal and EEG predictors that were not convolved with the canonical haemodynamic response function (cHRF). However, all convolved EEG predictors strongly correlated with the T2*-weighted signal variation in various regions including the bilateral superior temporal cortex, supplementary motor area, medial parietal cortex and cerebellum. The finding that movement onset spikes in the EEG predict T2*-weighted signal intensity only when the time course of movements is convolved with the cHRF, suggests that the correlated signal might reflect a BOLD response to neural activity associated with head movement. Furthermore, the observation that broad-spectral EEG spikes tend to occur at the same time as abrupt head movements, together with the finding that abrupt movements and EEG spikes show similar correlations with the T2*-weighted signal, indicates that the EEG spikes are produced by abrupt movement and that continuous regressors of EEG oscillations contain motion-related noise even after stringent correction of the EEG data. If not properly removed, these artefacts complicate the use of EEG data as a predictor of T2*-weighted signal variation. PMID:21763774

Jansen, Marije; White, Thomas P; Mullinger, Karen J; Liddle, Elizabeth B; Gowland, Penny A; Francis, Susan T; Bowtell, Richard; Liddle, Peter F



Common Genetic Origins for EEG, Alcoholism and Anxiety: The Role of CRH-BP  

Microsoft Academic Search

The resting EEG is a dynamic index of cortical activation, cognitive function and consciousness and is therefore an intermediate phenotype for many behaviors in which arousal is implicated such as anxiety and alcoholism. We performed a dense whole genome linkage scan using 3878 unlinked SNPs in a large pedigree derived from a population isolate sample of 328 Plains American Indians.

Mary-Anne Enoch; Pei-Hong Shen; Francesca Ducci; Qiaoping Yuan; Jixia Liu; Kenneth V. White; Bernard Albaugh; Colin A. Hodgkinson; David Goldman; Huibert D. Mansvelder



Autonomic and EEG Patterns during Eyes-Closed Rest and Transcendental Meditation (TM) Practice: The Basis for a Neural Model of TM Practice  

Microsoft Academic Search

In this single-blind within-subject study, autonomic and EEG variables were compared during 10-min, order-balanced eyes-closed rest and Transcendental Meditation (TM) sessions. TM sessions were distinguished by (1) lower breath rates, (2) lower skin conductance levels, (3) higher respiratory sinus arrhythmia levels, and (4) higher alpha anterior–posterior and frontal EEG coherence. Alpha power was not significantly different between conditions. These results

Frederick Travis; R. Keith Wallace



Visual illusions and travelling alpha waves produced by flicker at alpha frequency  

Microsoft Academic Search

The aim of the study was to obtain some experimental evidence of the ‘scanning hypothesis’ that links electroencephalogram (EEG) alpha-activity with rhythmically spreading waves in the visual cortex. The hypothesis was tested in experiments with 29 healthy adults. Under flicker stimulation through closed lids with the frequency of the individual alpha-rhythm, all subjects perceived illusory visual objects (a ring or

I. A. Shevelev; V. M. Kamenkovich; E. D. Bark; V. M Verkhlutov; G. A. Sharaev; E. S. Mikhailova



Vigilance Estimation Based on EEG Signals  

Microsoft Academic Search

In some tasks that require sustained attention, vigilance levels of the operator might become very important. EEG has been proved very effective for measuring vigilance. However, many difficulties exist in this field such as how to label the EEG data, how to remove the noise from the EEG data and so on. In this paper, we introduce a very useful

Hong Yu; Li-Chen Shi; Bao-Liang Lu


Hypofrontality on topographic EEG in schizophrenia  

Microsoft Academic Search

Summary Topographic EEG was performed in 17 DSM-III-R schizophrenic patients and in 15 sex- and agematched healthy controls. Eleven patients were firstonset (neuroleptic naive) schizophrenics. EEG band power was compared with psychopathology, neuropsychology and neurological soft signs. The EEG was recorded at 14 topographic locations monopolarly and movements of the eye and of the lid were monitored by two bipolar

Wagner F. Gattaz; Susanne Mayer; Peter Ziegler; Michael Platz; Theo Gasser



Integrating wireless EEGs into medical sensor networks  

Microsoft Academic Search

Wireless Electroencephalograms (EEG) are currently being used to wirelessly transmit the data from brain sensors to a computer and they carry huge potential for many future medical applications. This paper presents the design of a hybrid medical sensor network with Tmote Sky motes as wireless EEG sensor nodes at the lowest level collecting EEG signals and sending them to Stargate

Behçet Sarikaya; M. Abdul Alim; Siamak Rezaei



EEG transient event detection and classification using association rules.  


In this paper, a methodology for the automated detection and classification of transient events in electroencephalographic (EEG) recordings is presented. It is based on association rule mining and classifies transient events into four categories: epileptic spikes, muscle activity, eye blinking activity, and sharp alpha activity. The methodology involves four stages: 1) transient event detection; 2) clustering of transient events and feature extraction; 3) feature discretization and feature subset selection; and 4) association rule mining and classification of transient events. The methodology is evaluated using 25 EEG recordings, and the best obtained accuracy was 87.38%. The proposed approach combines high accuracy with the ability to provide interpretation for the decisions made, since it is based on a set of association rules. PMID:16871711

Exarchos, Themis P; Tzallas, Alexandros T; Fotiadis, Dimitrios I; Konitsiotis, Spiros; Giannopoulos, Sotirios



[A quantitative pharmaco-EEG study on psychotropic properties of cerebral metabolic enhancers: comparison between young and elderly healthy volunteers].  


In order to investigate psychotropic properties of cerebral metabolic enhancers (CMEs), the author carried out two identical quantitative pharmaco-EEG studies in different age groups of healthy volunteers; the young group (group-Y) consisted of six males between the ages of 21-26 years and elderly group (group-E) consisted of six males between the ages of 60-66 years. The drugs tested were five CMEs, dihydroergotoxine mesylate (DHE), propentofylline (PPF), nicergoline (NCG), lisuride maleate (LIS) and ibudilast (IDL). Each volunteer received either of the five test drugs or inert placebo in six one-day weekly sessions' according to single-blind, randomized crossover design. In each session, a single oral dose, equivalent to the clinically recommended daily dose, of either drug or placebo was administered and EEGs were recorded before and 1.3 and 6 hours after the drug administration. Firstly, the background EEGs before the drug administration were compared between the two groups. Group-E showed less slow activities and more alpha and fast activities than group -Y. This difference in background EEG profiles between two groups are considered to be due to physiological aging process. Secondly, drug effects on EEGs in two groups were compared. There were discrepancies in drug-induced EEG changes between the groups. In group-Y, any of the five tested CMEs did not induce EEG changes that were significantly different from placebo, whereas, in group-E, drug-induced EEG changes were more apparent. In group-E, DHE and PPF induced similar EEG changes, which were characterized by a decrease of alpha activity associated with marked decreases of slow and fast activities, the EEG profile similar to thymoleptics with sedative effects. LIS and IDL induced a decrease of alpha activity and an increase of fast activities, the profile close to thymoleptics with mood-elevating (stimulant) effects. NCG induced an increase of slow activities, the profile close to central depressants. These results in this study coincided with the experimental and subjective classification of the clinical effects of CMEs. Further analysis of EEG profiles based on principal component analysis indicated that there were two major components in background EEGs. There were discrepancies in the response to CMEs between two groups. In group-Y, CME-induced changes were seen mainly in the second principal component, while in group-E, the changes were seen mainly in the first principal component. These results suggested CMEs provoked thymoleptic effects by affecting the essential component of the EEG basic rhythm.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8356168

Nobuhara, K



Application of Independent Component Analysis for the Data Mining of Simultaneous EEG-fMRI: Preliminary Experience on Sleep Onset  

PubMed Central

The simultaneous acquisition of electroencephalogram (EEG) and functional MRI (fMRI) signals is potentially advantageous because of the superior resolution that is achieved in both the temporal and spatial domains, respectively. However, ballistocardiographic artifacts along with the ocular artifacts are a major obstacle for the detection of the EEG signatures of interest. Since the sources corresponding to these artifacts are independent from those producing the EEG signatures, we applied the Infomax-based independent component analysis (ICA) technique to separate the EEG signatures from the artifacts. The isolated EEG signatures were further utilized to model the canonical hemodynamic response functions (HRFs). Subsequently, the brain areas from which these EEG signatures originated were identified as locales of activation patterns from the analysis of fMRI data. Upon the identification and subsequent evaluation of brain areas generating interictal epileptic discharge (IED) spikes from an epileptic subject, the presented method was successfully applied to detect the theta- and alpha-rhythms that are sleep onset related EEG signatures along with the subsequent neural circuitries from a sleep deprived volunteer. These results suggest that the ICA technique may be useful for the preprocessing of simultaneous EEG-fMRI acquisitions, especially when a reference paradigm is unavailable.

Lee, Jong-Hwan; Oh, Sungsuk; Jolesz, Ferenc A.; Park, Hyunwook; Yoo, Seung-Schik



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

PubMed Central

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.

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



EEG Biofeedback: A Critical Evaluation of the Results and Underlying Rationale.  

National Technical Information Service (NTIS)

The fact that the gross frequency content of the EEG can be voluntarily manipulated is not new. Berger (1930) observed that subjects could suppress and enhance the new found alpha or 'Berger' rhythm by opening and closing their eyes. While this may seem t...

R. E. Townsend



PTSD Arousal and Depression Symptoms Associated With Increased Right-Sided Parietal EEG Asymmetry  

Microsoft Academic Search

Researchers have proposed that depression and particular types of anxiety are associated with unique patterns of regional brain activation. The authors examined the relationship among posttraumatic stress disorder (PTSD), anxiety, and depressive symptoms and frontal, temporal, and parietal EEG alpha asymmetry in female Vietnam War nurse veterans. The results indicate that PTSD arousal symptoms are associated with increased right-sided parietal

Linda J. Metzger; Stephen R. Paige; Margaret A. Carson; Natasha B. Lasko; Lynn A. Paulus; Roger K. Pitman; Scott P. Orr



Resting state EEG power and coherence abnormalities in bipolar disorder and schizophrenia.  


Resting state electroencephalogram (EEG) abnormalities in schizophrenia and bipolar disorder patients suggest alterations in neural oscillatory activity. However, few studies directly compare these anomalies between patient groups, and none have examined EEG coherence. Therefore, this study investigated whether these electrophysiological characteristics differentiate clinical populations from one another, and from non-psychiatric controls. To address this question, resting EEG power and coherence were assessed in 76 bipolar patients (BP), 132 schizophrenia patients (SZ), and 136 non-psychiatric controls (NC). We conducted separate repeated-measures ANOVAs to examine group differences within seven frequency bands across several brain regions. BP showed significantly greater power relative to SZ at higher frequencies including Beta and Gamma across all regions. In terms of intra-hemispheric coherence, while SZ generally exhibited higher coherence at Delta compared to NC and BP, both SZ and BP showed higher coherence at Alpha1 and Alpha2. In contrast, BP and HC showed higher coherence within hemispheres compared to SZ at Beta 1. In terms of inter-hemispheric coherence, SZ displayed higher coherence compared to NC at temporal sites at both Alpha1 and Alpha2. Taken together, BP exhibited increased high frequency power with few disruptions in neural synchronization. In contrast, SZ generally exhibited enhanced synchronization within and across hemispheres. These findings suggest that resting EEG can be a sensitive measure for differentiating between clinical disorders. PMID:24090715

Kam, Julia W Y; Bolbecker, Amanda R; O'Donnell, Brian F; Hetrick, William P; Brenner, Colleen A



Involvement of caspase-3, lipid peroxidation and TNF-alpha in causing apoptosis of macrophages by coordinately expressed Salmonella phenotype under stress conditions.  


Invasive Salmonella has been reported to induce apoptosis of macrophages as a part of its infection process, which may allow it to avoid detection by the innate immune system. However, the bacterial components capable of inducing apoptosis, particularly under the environments offered by the host have not been fully identified. Therefore, in the present study, attempts were made to evaluate the apoptotic potential of Salmonella enterica serovar Typhi (S. typhi) outer membrane protein expressed under stress conditions like iron, oxidative and anaerobic simulating the in vivo situations encountered by the pathogen. Analysis of data revealed that a coordinately expressed 69kDa outer membrane protein (OMP) expressed with enhanced intensity under iron, oxidative and anaerobic stress conditions caused apoptotic cell death in 51% of macrophages, whereas OMPs of S. typhi extracted under normal conditions accounted for apoptotic cell death in only 31% of macrophages. A significantly enhanced activity of caspase-3 was observed during macrophage-apoptosis induced by this protein. A significant increase in the extent of lipid peroxidation (levels of oxidant) and decrease in the activities of antioxidants was also observed which correlated with the increased generation of tumor necrosis factor-alpha, interleukine-1alpha and interleukine-6. These results suggest that caspase-3 and tumor necrosis factor-alpha in conjunction with other cytokines may induce apoptotic cell death through the up-regulation of oxidants and down-regulation of antioxidants. These findings may be relevant for the better understanding of the disease pathophysiology and for the future developments of diagnostic and preventive strategies during the host-pathogen interactions. PMID:17027970

Chanana, Vishal; Majumdar, Siddharth; Rishi, Praveen



EEG topography and tomography (LORETA) in diagnosis and pharmacotherapy of depression.  


Earlier investigations suggested an involvement of the right hemisphere and the left prefrontal cortex (PFC) in the pathogenesis of depression. This paper presents our own electroencephalographic (EEG) topography and low-resolution brain electromagnetic tomography (LORETA) data obtained in unmedicated depressed patients, and the effects of two representative drugs of non-sedative and sedative antidepressants, i.e., citalopram (CIT) and imipramine (IMI), as compared with placebo in normal subjects. Sixty female menopausal syndrome patients with the diagnosis of a depressive episode without psychotic symptoms as well as 30 healthy controls were investigated. Concerning the effects of antidepressants, normal healthy subjects received single oral doses of 20 mg CIT, 75 mg IMI and placebo p.o. A 3-min vigilance-controlled EEG and a 4-min resting EEG was recorded pre- and post-drug administration and analyzed by means of EEG mapping and LORETA. In the EEG mapping, depressed patients demonstrated a decrease in absolute power in all frequency bands, an augmentation of relative delta/theta and beta and a decrease in alpha activity as well as a slowing of the delta/theta centroid and an acceleration of the alpha and beta centroid, which suggests vigilance decrements. In the alpha asymmetry index, they showed right frontal hyper- and left frontal hypoactivation correlated with the Hamilton Depression Score (HAMD). LORETA predominantly revealed decreased power in the theta and alpha-1 frequency band. Negative correlations between theta power and the HAMD were observed in the ventro-medial PFC, the bilateral rostral anterior cingulate cortex (ACC) and the left insular cortex; between alpha-1 power and the HAMD in the right PFC. In the EEG mapping of antidepressants, 20 mg CIT showed mainly activating, 75 mg IMI partly sedative properties. LORETA revealed that CIT increased alpha-2, beta-1, beta-2 and beta-3 power more over the right than over the left hemisphere. However, also a left temporal and frontal delta increase was observed. In conclusion, EEG topography and tomography of depressed menopausal patients demonstrated a right frontal hyper- and left frontal hypoactivation in the alpha asymmetry index as well as a vigilance decrease, with a right-hemispheric preponderance. Within antidepressants at least 2 subtypes may be distinguished from the electrophysiological point of view, a non-sedative and a sedative. LORETA identifies cerebral generators responsible for the pathogenesis of depression as well as for the mode of action of antidepressants. PMID:21077572

Saletu, B; Anderer, P; Saletu-Zyhlarz, G M



Topographic EEG changes with normal aging and SDAT.  


EEG topography was compared in patients with senile dementia of the Alzheimer's type (SDAT), aged normal controls, and young normal controls to assess regional differences. The square root of absolute power was determined for each frequency using a Fast Fourier Transform (FFT). The normal elderly group showed a reduction in all 4 frequency bands, delta, theta, alpha and beta, at each of 32 leads when compared to the young controls. Z-transformation of the data revealed differences in topography. Older normals showed significantly greater mid-parietal and left mid-temporal delta than the younger controls. A similar pattern was seen for theta activity. Elderly controls showed relatively less occipital alpha and greater mid-parietal alpha. Beta activity demonstrated these same significant topographic differences. The elderly/SDAT comparison was significant for delta only. SDAT patients were characterized by a marked delta asymmetry in temporal regions which was not seen in the elderly normals. PMID:2467793

Breslau, J; Starr, A; Sicotte, N; Higa, J; Buchsbaum, M S



EEG\\/EP: New techniques  

Microsoft Academic Search

The topographic analysis of electrical brain activity consists of the extraction of quantitative features which adequately describe the scalp recorded electrical fields of the brain. In the beginning of brain electrical activity mapping most methods centered mainly around the graphical display of multichannel EEG and evoked potential data. Meanwhile quantitative analysis strategies have been developed, and such methods are applied

Wolfgang Skrandies



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


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. PMID:24060726

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



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

NASA Astrophysics Data System (ADS)

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.

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



PyEEG: An Open Source Python Module for EEG/MEG Feature Extraction  

PubMed Central

Computer-aided diagnosis of neural diseases from EEG signals (or other physiological signals that can be treated as time series, e.g., MEG) is an emerging field that has gained much attention in past years. Extracting features is a key component in the analysis of EEG signals. In our previous works, we have implemented many EEG feature extraction functions in the Python programming language. As Python is gaining more ground in scientific computing, an open source Python module for extracting EEG features has the potential to save much time for computational neuroscientists. In this paper, we introduce PyEEG, an open source Python module for EEG feature extraction.

Bao, Forrest Sheng; Liu, Xin; Zhang, Christina



Low levels of sarin affect the EEG in marmoset monkeys: a pilot study.  


The main purpose of this pilot study was to estimate the lowest observable adverse effect level (LOAEL) for the electroencephalogram (EEG) upon long-term, low-level exposure of vehicle-pretreated and pyridostigmine-pretreated marmoset monkeys to sarin vapour. This is the C.t value (t=5 h) of exposure at which the EEG becomes significantly different from that resulting from air exposure of the same animals. The LOAELs for effects on the EEG in vehicle- and pyridostigmine-pretreated marmosets appeared to be 0.2 and 0.1 mg min m(-3), respectively. Comparatively, the latter LOAEL values are at least an order of magnitude lower than the previously established LOAEL for miosis and only 2-5 times higher than the lowest observable effect level (LOEL) of bound sarin in blood. The second aim of the study was to analyse the EEG of the same marmosets again during a 5-h exposure to air 1 year after exposure to sarin vapour. All the marmosets still demonstrated significant (P <0.05) EEG differences. In most vehicle-pretreated marmosets the energy (microV2) per EEG band was higher than that observed 1 year earlier, which might indicate that neurons had become more sensitive to excitation. This phenomenon was less pronounced in pyridostigmine-pretreated animals. Visual examination of the EEG records revealed clear bursts of alpha frequencies (ca. 9 Hz), resembling sleep-spindles, that were present more frequently in both groups of exposed marmosets than in naive animals. These late changes in spindle oscillation might be the result of changes in the cholinergic system due to exposure to sarin vapour 1 year previously. In conclusion, EEG abnormalities persisting for more than 1 year may occur in humans during long-term (5 h) exposure to subclinical levels of sarin that are not detectable by the currently fielded alarm systems. PMID:15558834

van Helden, Herman P M; Vanwersch, Raymond A P; Kuijpers, Willem C; Trap, Henk C; Philippens, Ingrid H C; Benschop, Hendrik P


A new way of building a database of EEG findings  

Microsoft Academic Search

Whereas computer-based electroencephalography (EEG) is widely applied, the EEG interpretations are usually not stored in a way that favours exploitation of modern computer technology. This paper reports an EEG description system facilitating categorization of EEG data in a computerized database. The system interactively communicates with the digital EEG system and also with the general patient administrative system. The main new

H Aurlien; I. O Gjerde; N. E Gilhus; O. G Hovstad; B Karlsen; H Skeidsvoll



[Study of zopiclone with quantitative EEG analysis and topography].  


Zopiclone is a cyclopyrrolone derivative which possesses hypnotic activity. This drug is known to increase the slow sleep stage compared to benzodiazepines in polysomnography. The subjects were 10 right-handed healthy male volunteers aged 21-23 years. Double-blind crossover trials with placebo control were conducted in a random sequence at intervals of 1 week. Zopiclone 7.5 mg and placebo were administered as single oral doses. Three-minute vigilance controlled EEGs at before and at 1, 3, and 5 h after drug administration, and the response times were recorded. One minute out of the 3-minute EEGs was analyzed with FFT and the power spectrum was obtained. Then the absolute amplitude power (microV) was calculated. These results were subjected to Student's t-test (double difference) and displayed with topographic maps (t statistic significance probability mapping). Zopiclone prolonged the latency of the response time, and increased the amount of delta absolute amplitude power over the right central region, beta 1 absolute amplitude power over the left central region and beta 2 absolute amplitude power over the right central area along with decreased alpha absolute amplitude power over the occipital region and theta power over the left frontal pole area after 1 h, when the peak pharmacological effect was expected. The EEG profiles of zopiclone were different from that of diazepam reported previously concerning the increase in delta activity. PMID:7584730

Yamadera, H; Kato, M; Tsukahara, Y; Okuma, T



EEG findings in dementia with Lewy bodies and Alzheimer's disease  

PubMed Central

OBJECTIVES—To evaluate the role of the EEG in the diagnosis of dementia with Lewy bodies (DLB).?METHODS—Standard EEG recordings from 14 patients with DLB confirmed at postmortem were examined and were compared with the records from 11 patients with Alzheimer's disease confirmed at postmortem?RESULTS—Seventeen of the total of 19 records from the patients with DLB were abnormal. Thirteen showed loss of alpha activity as the dominant rhythm and half had slow wave transient activity in the temporal lobe areas. This slow wave transient activity correlated with a clinical history of loss of consciousness. The patients with Alzheimer's disease were less likely to show transient slow waves and tended to have less marked slowing of dominant rhythm.?CONCLUSIONS—The greater slowing of the EEG in DLB than in Alzheimer's disease may be related to a greater loss of choline acetyltransferase found in DLB. Temporal slow wave transients may be a useful diagnostic feature in DLB and may help to explain the transient disturbance of consciousness which is characteristic of the disorder.??

Briel, R; McKeith, I; Barker, W; Hewitt, Y; Perry, R; Ince, P; Fairbairn, A



Cortical sources of resting state EEG rhythms are sensitive to the progression of early stage Alzheimer's disease.  


Cortical sources of resting state electroencephalographic (EEG) rhythms are abnormal in subjects with Alzheimer's disease (AD). Here we tested the hypothesis that these sources are also sensitive to the progression of early stage AD over the course of one year. The resting state eyes-closed EEG data were recorded in 88 mild AD patients at baseline (Mini Mental State Evaluation, MMSE I = 21.7 ± 0.2 standard error, SE) and at approximately one-year follow up (13.3 months ± 0.5 SE; MMSE II = 20 ± 0.4 SE). All patients received standard therapy with acetylcholinesterase inhibitors. EEG recordings were also performed in 35 normal elderly (Nold) subjects as controls. 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), beta 2 (20-30 Hz), and gamma (30-40 Hz). Cortical EEG sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Compared to the Nold subjects, the mild AD patients were characterized by a power increase of widespread delta sources and by a power decrease of posterior alpha sources. In the mild AD patients, the follow-up EEG recordings showed increased power of widespread delta sources as well as decreased power of widespread alpha and posterior beta 1 sources. These results suggest that the resting state EEG sources were sensitive, at least at group level, to the cognitive decline occurring in the mild AD group over a one-year period, and might represent cost-effective and non-invasive markers with which to enrich cohorts of AD patients that decline faster for clinical studies. PMID:23340039

Babiloni, Claudio; Lizio, Roberta; Del Percio, Claudio; Marzano, Nicola; Soricelli, Andrea; Salvatore, Elena; Ferri, Raffaele; Cosentino, Filomena I I; Tedeschi, Gioacchino; Montella, Patrizia; Marino, Silvia; De Salvo, Simona; Rodriguez, Guido; Nobili, Flavio; Vernieri, Fabrizio; Ursini, Francesca; Mundi, Ciro; Richardson, Jill C; Frisoni, Giovanni B; Rossini, Paolo M



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


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

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



Reductions in qEEG slowing over 1 year and after treatment with Cerebrolysin in patients with moderate-severe traumatic brain injury.  


Changes in quantitative EEG (qEEG) recordings over a 1-year period and the effects of Cerebrolysin (Cere) on qEEG slowing and cognitive performance were investigated in postacute moderate-severe traumatic brain injury (TBI) patients. Time-related changes in qEEG activity frequency bands (increases of alpha and beta, and reductions of theta and delta relative power) and in qEEG slowing (reduction of EEG power ratio) were statistically significant in patients with a disease progress of less than 2 years at baseline, but not in those patients having a longer disease progress time. Slowing of qEEG activity was also found to be significantly reduced in TBI patients after 1 month of treatment with Cere and 3 months later. Therefore, Cere seems to accelerate the time-related reduction of qEEG slowing occurring in untreated patients. The decrease of qEEG slowing induced by Cere correlated with the improvement of attention and working memory. Results of this exploratory study suggest that Cere might improve the functional recovery after brain injury and encourage the conduction of further controlled clinical trials. PMID:18273537

Alvarez, X Antón; Sampedro, Carolina; Figueroa, Jesús; Tellado, Iván; González, Andrés; García-Fantini, Manuel; Cacabelos, Ramón; Muresanu, Dafin; Moessler, Herbert



[Biologic artifacts in quantitative EEG].  


We studied the influence of five biologic artifacts sources on quantitative EEG (blinking, forced eyes closure, forced jaw closure, tongue movements and pursuit eyes movements) through both visual and spectral analysis, with the purpose of verifying how do these artifacts can be seen in a cartographic way. We found that the spectrums potentials showed the same topographic display that was found through visual analysis. Visual analysis was superior than the quantitative evaluation to recognise the artifacts, as the former preserved the morphological display of the paroxysms. However it is important know how do the potentials are represented in quantitative maps, so that they can be identified as artifacts and not as pathologic EEG activity. PMID:16791367

Anghinah, Renato; Basile, Luis I; Schmidt, Magali T; Sameshima, Koichi; Gattaz, Wagner Farid



Residual brain dysfunction observed one year post-mild traumatic brain injury: Combined EEG and balance study  

PubMed Central

Objectives There is still considerable debate and controversy about whether EEG can be used as a robust clinical tool for assessment of mild traumatic brain injury (MTBI). Nonhomogeneous subject populations, inaccurate assessment of severity of brain injury, time since injury when EEG testing was performed, the lack of EEG research conducted serially and in conjunction with other behavioral measures as injury evolves over time may contribute to the existing controversies. In this study, we implemented a concussion assessment protocol combining a series of EEG and balance measures throughout one year post-injury to document the efficacy of EEG and balance measures as relate to differential recovery of patients suffering from MTBI. Methods Three hundred and eighty subjects at risk for MTBI were initially recruited for baseline testing. Forty nine from this initial subjects pool subsequently suffered a single episode of concussive blow and were tested on day 7, 15, 30 days, 6 months and 12 months post-injury. EEGs were recorded while sitting, standing on the force plate and then on a foam base of support with eyes open/closed conditions. EEG alpha power (8–12 Hz) and its percent suppression from sitting to standing postures were computed. The center of pressure (COP) measures were obtained from the force platform and analyzed for eyes open and eyes closed conditions. Results Percent alpha power suppression from sitting to standing postural conditions significantly increased in MTBI subjects shortly after the injury (p < 0.01). Percent alpha power suppression significantly correlated with increased area of COP during standing posture with eye closed (r2 = 0.53, p < 0.01). The magnitude of alpha power suppression predicted the rate of recovery of this measure in sub-acute and chronic phases of injury (r2 = 0.609, p < 0.01). Finally, 85% of MTBI subjects who showed more than 20% of alpha power suppression in the acute phase of injury did not return to pre-injury status up to 12 months post-injury. Conclusions The efficacy of serially implemented EEG measures in conjunction with balance assessment over the course of MTBI evolution to document residual cerebral dysfunction was demonstrated. Specifically, alteration of EEG alpha power dynamics in conjunction with balance data in the acute phase of injury with respect to baseline measures may predict the rate of recovery from a single concussive blow. Significance Neurophysiological measures are excellent tools to assess the status and prognosis of patients with MTBI.

Slobounov, Semyon; Sebastianelli, Wayne; Hallett, Mark



The Added Value of Simultaneous EEG and Amplitude-Integrated EEG Recordings in Three Newborn Infants  

Microsoft Academic Search

Amplitude-integrated electroencephalograms (aEEGs) recorded by cerebral function monitors (CFMs) are used increasingly to monitor the cerebral activity of newborn infants with encephalopathy. Recently, new CFM devices became available which also reveal the original EEG signals from the same leads. To date it was unclear whether this single-lead EEG provides additional information towards interpreting the aEEG traces more accurately. Our report

Nathalie K. S. de Vries; Hendrik J. ter Horst; Arend F. Bos



EEG Quality: Origin and Reduction of the EEG Cardiac-Related Artefact  

Microsoft Academic Search

\\u000a With the advent of purpose-built “MR-compatible” EEG recording hardware, the simultaneous acquisition of EEG and fMRI has\\u000a recently become more widespread (for reviews, see Herrmann and Debener 2007; Laufs et al. 2008). Nevertheless, the MRI scanner\\u000a remains a hostile environment for EEG recordings, and ensuring good EEG signal quality can be a challenging task (e.g. Parkes\\u000a et al. 2006). The

Stefan Debener; Cornelia Kranczioch; Ingmar Gutberlet


EEG Signal Analysis: A Survey  

Microsoft Academic Search

The EEG (Electroencephalogram) signal indicates the electrical activity of the brain. They are highly random in nature and\\u000a may contain useful information about the brain state. However, it is very difficult to get useful information from these signals\\u000a directly in the time domain just by observing them. They are basically non-linear and nonstationary in nature. Hence, important\\u000a features can be

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



21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Electroencephalogram (EEG) signal spectrum analyzer. 882.1420... § 882.1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a...



21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Electroencephalogram (EEG) signal spectrum analyzer. 882.1420... § 882.1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a...



Age-related changes in qEEG during cognitive tasks.  


Early diagnosis of dementia can be difficult. Quantitative EEG (qEEG) in combination with cognitive tasks shows promise for improving diagnostic accuracy. The study of task induced qEEG changes in normal ageing is a prerequisite for differentiating these changes from those which are specific to dementia. Sixteen young adults (mean age 28.8+/-5.6 years) and 16 healthy cognitively normal older subjects (mean age 73.4+/-7.9 years) participated in the study. EEG recordings were made while subjects were in a relaxed (or resting) state, and also while they performed arithmetic and language tasks. From the resting to the arithmetic conditions, there was decreased alpha activity and increased delta and beta-3 activity for both subject groups. Changes in alpha and delta activity were found in almost all sites and could be associated with arousal. Increase in beta-3 activity was focal, appearing only in the posterior region of the brain and it could be assumed that this area is highly involved in arithmetic processes. In the young adult group, theta activity increased from the resting to the arithmetic conditions, while in the older group theta activity changes were in the opposite direction. From the resting to the language condition, there was increased delta activity and decreased alpha and beta-1 activity for both subject groups. Changes in alpha and delta activity were again found in almost all sites. The decrease in beta-1 activity was found in only four sites, but these were not specific to a region of the brain known to be involved in language processing. This consistency in qEEG changes during cognitive tasks suggests that the method can be applied to the investigation of cognitive deficits associated with a number of neurological syndromes. PMID:9845017

Widagdo, M M; Pierson, J M; Helme, R D



Fundamentals of EEG Methodology in Concussion Research  

Microsoft Academic Search

The EEG in humans was first demonstrated by Hans Berger in the 1920s. His initial speculation that EEG could give us insight\\u000a into physiological and cognitive processes has been validated in a variety of situations ranging from sleep to wakefulness\\u000a as well as physiological concomitants of a variety of cognitive events. The current chapter will review basic EEG processes\\u000a and

William J. Ray; Semyon Slobounov


Methodology for Combined TMS and EEG  

Microsoft Academic Search

The combination of transcranial magnetic stimulation (TMS) with simultaneous electroencephalography (EEG) provides us the\\u000a possibility to non-invasively probe the brain’s excitability, time-resolved connectivity and instantaneous state. Early attempts\\u000a to combine TMS and EEG suffered from the huge electromagnetic artifacts seen in EEG as a result of the electric field induced\\u000a by the stimulus pulses. To deal with this problem, TMS-compatible

Risto J. IlmoniemiDubravko; Dubravko Ki?i?



EEG spectral profile to stage Alzheimer's disease  

Microsoft Academic Search

Objective:The present study was undertaken to investigate whether a synoptic parameter of quantitative EEG (qEEG), such as the power spectral profile, may be used as a simple marker to stage Alzheimer's disease (AD) in the clinical setting.Methods:To this purpose, the qEEG spectral profile was examined in 48 patients (mean age: 73 years) with probable (NINCDS-ADRDA criteria) AD, who were divided

Guido Rodriguez; Francesco Copello; Paolo Vitali; Germana Perego; Flavio Nobili



EEG Data Driven Animation and Its Application  

Microsoft Academic Search

Human electroencephalograph (EEG) data driven animation is often used in neurofeedback systems for concentration training\\u000a in children and adults. Visualization of the time-series data could be used in neurofeedback and for the data analysis. The\\u000a paper proposes a novel method of 3D mapping of EEG data and describes visualization system VisBrain that was developed for\\u000a EEG data analysis. We employed

Olga Sourina; Alexei Sourin; Vladimir Kulish



Independent EEG Sources Are Dipolar  

PubMed Central

Independent component analysis (ICA) and blind source separation (BSS) methods are increasingly used to separate individual brain and non-brain source signals mixed by volume conduction in electroencephalographic (EEG) and other electrophysiological recordings. We compared results of decomposing thirteen 71-channel human scalp EEG datasets by 22 ICA and BSS algorithms, assessing the pairwise mutual information (PMI) in scalp channel pairs, the remaining PMI in component pairs, the overall mutual information reduction (MIR) effected by each decomposition, and decomposition ‘dipolarity’ defined as the number of component scalp maps matching the projection of a single equivalent dipole with less than a given residual variance. The least well-performing algorithm was principal component analysis (PCA); best performing were AMICA and other likelihood/mutual information based ICA methods. Though these and other commonly-used decomposition methods returned many similar components, across 18 ICA/BSS algorithms mean dipolarity varied linearly with both MIR and with PMI remaining between the resulting component time courses, a result compatible with an interpretation of many maximally independent EEG components as being volume-conducted projections of partially-synchronous local cortical field activity within single compact cortical domains. To encourage further method comparisons, the data and software used to prepare the results have been made available (

Delorme, Arnaud; Palmer, Jason; Onton, Julie; Oostenveld, Robert; Makeig, Scott



A distinguishing method of epileptic EEG and deglutition EEG based on chaotic noise-reduction  

Microsoft Academic Search

A new method for recovering epileptic EEG and deglutition EEG's nonnoise trajectory and distinguishing these two waveforms is presented. The main aim of this paper is to introduce the theory and establish a mathematical model of the simple recovery of the EEG's nonnoise trajectory. This method is finally used in experiments. Our results prove that chaotic dynamics do exist in

Guanghua Ouyang; Chunyan Li; Guotai Jiang



Distinguish Method of Epileptic EEG and Deglutition EEG Based on Chaotic Noise-Reduction.  

National Technical Information Service (NTIS)

A new method for recovering epileptic EEG and deglutition EEG's nonnoise trajectory and distinguishing these two waveforms is presented. The main aim of this paper is to introduce the theory and establish math model of a simple recovering EEG's nonnoise t...

G. Ouyang C. Li G. Jiang



Phenotype-genotype characterization of alpha-thalassemia mental retardation syndrome due to isolated monosomy of 16p13.3.  


An 8-year-old Caucasian girl presented with mild dysmorphic features and intellectual disability (ID) affecting multiple spheres. Dysmorphisms included a high forehead with up-slanting palpebral fissures, prominent nasal root and bridge, flattened maxilla, high-arched palate, and anterior frenulum. Structural brain anomalies included reduced periventricular white matter volume and thin corpus callosum. The presence of HbH bodies and her clinical presentation raised suspicion for autosomal alpha-thalassemia mental retardation syndrome (ATR-16). Whole-genome array analysis at 1 Mb resolution was performed, which revealed a sub-microscopic loss of 16p involving clones RP11-344L6 at 0.1 Mb, RP1-121I4 at 0.2 Mb and RP11-334D3 at 1 Mb. FISH confirmed deletion (del) of the terminal clone (RP1-121I4) on 16pter, which was de novo in origin. The more proximal clone RP11-334D3 (at 1 Mb) showed diminished FISH signal intensity on one of the homologues, suggesting that one breakpoint occurred within this clone. Quantitative PCR (qPCR) confirmed a de novo deletion encompassing SOX8 (at 0.97 Mb). ATR-16 is characterized by ID with mild, nonspecific dysmorphic features, and is associated with terminal del16p (MIM No. 141750). Cases of isolated monosomy for 16p are rarely described; such descriptions help to delineate the syndrome in the absence of confounding karyotypic anomalies. We describe detailed molecular cytogenetic and clinical findings relating to a subject with ATR-16. PMID:18076105

Gibson, William T; Harvard, Chansonette; Qiao, Ying; Somerville, Martin J; Lewis, M E Suzanne; Rajcan-Separovic, Evica



Estimating brain load from the EEG.  


Modern work requires cognitively demanding multitasking and the need for sustained vigilance, which may result in work-related stress and may increase the possibility of human error. Objective methods for estimating cognitive overload and mental fatigue of the brain on-line, during work performance, are needed. We present a two-channel electroencephalography (EEG)-based index, theta Fz/alpha Pz ratio, potentially implementable into a compact wearable device. The index reacts to both acute external and cumulative internal load. The index increased with the number of tasks to be performed concurrently (p = 0.004) and with increased time awake, both after normal sleep (p = 0.002) and sleep restriction (p = 0.004). Moreover, the increase of the index was more pronounced in the afternoon after sleep restriction (p = 0.006). As a measure of brain state and its dynamics, the index can be considered equivalent to the heartbeat, an indicator of the cardiovascular state, thus inspiring the name "brainbeat". PMID:19618092

Holm, Anu; Lukander, Kristian; Korpela, Jussi; Sallinen, Mikael; Müller, Kiti M I



Effects of Ayahuasca on the human EEG.  


EEG data were recorded under field conditions from 11 members of the Santo Daime Doctrine, a Brazilian shamanistic religion, before and after ingesting the psychoactive alkaloid preparation, ayahuasca, or daime, as they term it. Post-ingestion, we observed increases in power in the 36-44 Hz frequency band ("40 Hz") from the left occipital-temporal-parietal scalp electrodes in the eyes-closed condition, which extended to most of the posterior scalp in the eyes-open condition. The results are consistent with many reports that ayahuasca intensifies visual imagery. These results are discussed in terms of a thalamocortical model of the role of 40 Hz activity in brain function and conscious experience. We also noted tendencies toward decreases in the power of slow (theta and alpha) brain rhythms, and increases in the 14-30 Hz beta band, in accord with studies reported 30 years ago with other consciousness-altering compounds. Analysis of four ayahuasca samples yielded an average composition per ingested dose (75 ml) of 55.6 mg harmine, 43.9 mg tetrahydroharmine, 41.3 mg N,N-dimethyltryptamine (DMT), 4.6 mg harmaline, and 3.1 mg harmol. The DMT appeared to be of sufficient concentration to promote psychoactive effects, while the ?-carbolines functioned to supply MAO inhibitors necessary to prevent degradation of DMT and to maintain its oral activity. PMID:23195759

Don, N S; McDonough, B E; Moura, G; Warren, C A; Kawanishi, K; Tomita, H; Tachibana, Y; Böhlke, M; Farnsworth, N R



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


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

Garces Correa, Agustina; Laciar Leber, Eric



The neurobiology of the EEG biomarker as a predictor of treatment response in depression.  


The management of depression remains a constant challenge in clinical practice. This is largely due to the fact that initial treatments frequently do not lead to remission and recovery. The current treatment approach involves lengthy trial-and-error periods. It would be beneficial to have early reliable predictors to determine whether patients will respond to treatment or not. Electroencephalography (EEG) derived biomarkers namely change in the activity of EEG frequency bands, hemispheric alpha asymmetry, theta cordance, the antidepressant treatment response index (ATR) and evoked potentials have all been shown to predict response to a variety of antidepressant medications. However, the neurobiology in support of this association has been largely unexplored. In this review, we discuss biological mechanisms for each EEG derived biomarker predictive of treatment response. Validating such biomarkers will not only greatly aid clinicians in selecting antidepressant treatment for individual patients but will also provide a critical step in drug discovery. PMID:22569197

Baskaran, Anusha; Milev, Roumen; McIntyre, Roger S



Alpha Neurofeedback Training for Performance Enhancement: Reviewing the Methodology  

Microsoft Academic Search

Introduction. Considerable interest has been, and still is, generated by the potential performance enhancing benefits of alpha neurofeedback training (NFT) for healthy participants. A plausible rationale for such training, with an aim to improve mood and\\/or enhance cognition, can be made based upon what is already known of the links between alpha EEG activity and behavior. However, designing an optimal

D. Vernon; T. Dempster; O. Bazanova; N. Rutterford; M. Pasqualini; S. Andersen



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

PubMed Central

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 (>100M?), 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 that can be applied easily and quickly can surmount these obstacles without compromising technical quality.



Preterm EEG: a multimodal neurophysiological protocol.  


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

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



EEG-fMRI validation studies in comparison with icEEG: a review.  


Simultaneous EEG-fMRI is a non-invasive investigation technique developed to localize the generators of interictal epileptiform discharges (IED) in patients with epilepsy. Although the value of EEG-fMRI in epilepsy presurgical evaluation is being assessed clinically, its utility is still controversial. In this review, we considered EEG-fMRI applications in epilepsy presurgical evaluation with a focus on validation studies that compared the results of EEG-fMRI with those of the current "gold standard" intracranial EEG (icEEG) in order to assess its utility of seizure focus localization and the possibility for EEG-fMRI to reduce the need for invasive techniques such as icEEG. Since the advances of EEG-fMRI partially rely on the maturation of its data analysis, we also reviewed the methodological developments in EEG-fMRI analysis. It is possible that combining with other neuroimaging modalities such as MEG/MSI and ESI, EEG-fMRI may play a greater role in epilepsy presurgical evaluation. PMID:22342239

Zhang, Jing; Liu, Weifang; Chen, Hui; Xia, Hong; Zhou, Zhen; Wang, Lei; Mei, Shanshan; Liu, Qingzhu; Li, Yunlin



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


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

Fingelkurts, Al A; Fingelkurts, An A



Characterizing Alzheimer's Disease Severity via Resting-Awake EEG Amplitude Modulation Analysis.  


Changes in electroencephalography (EEG) amplitude modulations have recently been linked with early-stage Alzheimer's disease (AD). Existing tools available to perform such analysis (e.g., detrended fluctuation analysis), however, provide limited gains in discriminability power over traditional spectral based EEG analysis. In this paper, we explore the use of an innovative EEG amplitude modulation analysis technique based on spectro-temporal signal processing. More specifically, full-band EEG signals are first decomposed into the five well-known frequency bands and the envelopes are then extracted via a Hilbert transform. Each of the five envelopes are further decomposed into four so-called modulation bands, which were chosen to coincide with the delta, theta, alpha and beta frequency bands. Experiments on a resting-awake EEG dataset collected from 76 participants (27 healthy controls, 27 diagnosed with mild-AD, and 22 with moderate-AD) showed significant differences in amplitude modulations between the three groups. Most notably, i) delta modulation of the beta frequency band disappeared with an increase in disease severity (from mild to moderate AD), ii) delta modulation of the theta band appeared with an increase in severity, and iii) delta modulation of the beta frequency band showed to be a reliable discriminant feature between healthy controls and mild-AD patients. Taken together, it is hoped that the developed tool can be used to assist clinicians not only with early detection of Alzheimer's disease, but also to monitor its progression. PMID:24015222

Fraga, Francisco J; Falk, Tiago H; Kanda, Paulo A M; Anghinah, Renato



Atypical EEG Power Correlates With Indiscriminately Friendly Behavior in Internationally Adopted Children  

PubMed Central

While effects of institutional care on behavioral development have been studied extensively, effects on neural systems underlying these socioemotional and attention deficits are only beginning to be examined. The current study assessed electroencephalogram (EEG) power in 18-month-old internationally adopted, post-institutionalized children (n = 37) and comparison groups of non-adopted children (n = 47) and children internationally adopted from foster care (n = 39). For their age, post-institutionalized children had an atypical EEG power distribution, with relative power concentrated in lower frequency bands compared to non-adopted children. Both internationally adopted groups had lower absolute alpha power than non-adopted children. EEG power was not related to growth at adoption or to global cognitive ability. Atypical EEG power distribution at 18 months predicted indiscriminate friendliness and poorer inhibitory control at 36 months. Both post-institutionalized and foster care children were more likely than non-adopted children to exhibit indiscriminate friendliness. Results are consistent with a cortical hypoactivation model of the effects of early deprivation on neural development and provide initial evidence associating this atypical EEG pattern with indiscriminate friendliness. Outcomes observed in the foster care children raise questions about the specificity of institutional rearing as a risk factor and emphasize the need for broader consideration of the effects of early deprivation and disruptions in care.

Tarullo, Amanda R.; Garvin, Melissa C.; Gunnar, Megan R.



Atypical EEG power correlates with indiscriminately friendly behavior in internationally adopted children.  


While effects of institutional care on behavioral development have been studied extensively, effects on neural systems underlying these socioemotional and attention deficits are only beginning to be examined. The current study assessed electroencephalogram (EEG) power in 18-month-old internationally adopted, postinstitutionalized children (n = 37) and comparison groups of nonadopted children (n = 47) and children internationally adopted from foster care (n = 39). For their age, postinstitutionalized children had an atypical EEG power distribution, with relative power concentrated in lower frequency bands compared with nonadopted children. Both internationally adopted groups had lower absolute alpha power than nonadopted children. EEG power was not related to growth at adoption or to global cognitive ability. Atypical EEG power distribution at 18 months predicted indiscriminate friendliness and poorer inhibitory control at 36 months. Both postinstitutionalized and foster care children were more likely than nonadopted children to exhibit indiscriminate friendliness. Results are consistent with a cortical hypoactivation model of the effects of early deprivation on neural development and provide initial evidence associating this atypical EEG pattern with indiscriminate friendliness. Outcomes observed in the foster care children raise questions about the specificity of institutional rearing as a risk factor and emphasize the need for broader consideration of the effects of early deprivation and disruptions in care. PMID:21171750

Tarullo, Amanda R; Garvin, Melissa C; Gunnar, Megan R



The Effect of Pre vs. Post-Reward Attainment on EEG Asymmetry in Melancholic Depression  

PubMed Central

Clinical investigators have long theorized about the role of reward processing and positive affect in depression. One theory posits that compared to nonmelancholic depressives, melancholic depressives experience less consummatory (i.e., post-reward), but comparably low anticipatory (prior to reward), positive affect. We tested whether frontal EEG asymmetry, a putative marker of the anticipatory reward system, is present only before an individual receives a reward or also after receiving a reward (i.e., during consummatory reward processing). We also examined whether melancholic depression, a condition characterized by a deficit in consummatory reward processing, is associated with abnormal EEG asymmetries in alphab and power. Effects in other frequency bands (delta, theta, or beta) were also explored. EEG was recorded in 34 controls, 48 nonmelancholic depressives, and 17 melancholic depressives during a slot machine task designed to elicit anticipatory and consummatory reward processing. Results indicated that, for alpha, the frontal EEG asymmetry of greater relative left activity was specific to anticipatory reward processing. During the consummatory phase, individuals with melancholic depression exhibited different posterior EEG asymmetries than individuals with nonmelancholic depression and controls at a trend level. This second finding was largely due to melancholics exhibiting relatively lower right posterior activity and nonmelancholics exhibiting relatively lower left activity. These results suggest that a posterior asymmetry may be a marker for melancholic depression and aberrant consummatory reward processing.

Shankman, Stewart A.; Sarapas, Casey; Klein, Daniel N.



Anticipatory Electroencephalography Alpha Rhythm Predicts Subjective Perception of Pain Intensity  

Microsoft Academic Search

This high-resolution electroencephalography (EEG) study tested the hypothesis that the suppression of rolandic alpha power before predictable painful stimulation affects the subject’s subsequent evaluation of pain intensity, as a reflection of the influence of expectancy processes on painful stimulus processing. High-resolution EEG data were recorded (126 channels) from 10 healthy adult volunteers during the expectancy of a painful CO2-laser stimulation

Claudio Babiloni; Alfredo Brancucci; Claudio Del Percio; Paolo Capotosto; Lars Arendt-Nielsen; Andrew C. N. Chen; Paolo Maria Rossini



Nonlinear considerations in EEG signal classification  

Microsoft Academic Search

We investigate the effect of incorporating modeling of nonlinearity on the classification of electroencephalogram (EEG) signals using an artificial neural network (ANN). It is observed that the ANN's predictive ability is improved after preprocessing EEG signals using a particular nonlinear modeling technique, viz. a bilinear model, compared with those obtained by using a particular classical linear analysis method, viz. an

Neep Hazarika; Ah Chung Tsoi; Alex A. Sergejew



Multichannel Analysis of the Newborn EEG Data  

Microsoft Academic Search

EEG is one of the most important methods of studying the maturation of the child brain. A newborn infant typically sleeps approximately 70 per cent of 24 hour interval. Sleep in infants is significantly different from sleep in adults. This paper addresses the problem of multichannel analysis of newborn EEG signals. The designed technique will be applicable to other similar

Vaclav Gerla; Lenka Lhotska; Vladimir Krajca; Karel Paul


Nonnegative Tensor Factorization for Continuous EEG Classification  

Microsoft Academic Search

Abstract In this paper we present a method for continuous EEG classification, where we employ nonnegative tensor factorization (NTF) to determine discriminative spectral features and use the Viterbi algorithm to continuously classify multiple mental tasks. This is an extension of our previous work on the use of nonnegative matrix factorization (NMF) for EEG classification. Numerical experiments with two data sets

Hyekyoung Lee; Yong-deok Kim; Andrzej Cichocki; Seungjin Choi



EEG Coherence and Dissociative Identity Disorder  

Microsoft Academic Search

This is the first study to apply EEG coherence analysis to the study of Dissociative Identity Disorder (DID). EEG coherence is argued to be an objective measure of cortical connectivity. Five DID patients were compared to five controls, who were professional actors. Fifteen dissociated DID alter states were studied, as were 15 “alters” simulated by the actor control participants. Comparisons

Annedore Hopper; Joseph Ciorciari; Gillian Johnson; John Spensley; Alex Sergejew; Con Stough



Topographic EEG mapping of the relaxation response  

Microsoft Academic Search

The purpose of this study was to assess the central nervous system effects of the relaxation response (RR) in novice subjects using a controlled, within-subjects design and topographic EEG mapping as the dependent measure. Twenty subjects listened to a RR and control audiotape presented in a counterbalanced order while EEG was recorded from 14 scalp locations. TheRR condition produced greater

Gregg D. Jacobs; Herbert Benson; Richard Friedman



Genetic and Environmental Influences on EEG Coherence  

Microsoft Academic Search

EEG coherence measures the covariation in electrical brain activity between two locations on the scalp and is used to study connectivity between cortical regions. The aim of this study was to determine the heritability of EEG coherence. Coherence was measured in a group of 213 16-yr-old twin pairs. By including male and female twin pairs in the sample, sex differences

C. E. M. van Beijsterveldt; P. C. M. Molenaar; E. J. C. de Geus; D. I. Boomsma



EEG Analyzer prototype based on FPGA  

Microsoft Academic Search

The paper presents an implementation of a FPGA- based prototype for an EEG Analyzer device. It is a portable biomedical device that performs electroencephalographic (EEG) signal analysis targeted at real-time in-field diagnostics of human brain disorders such as depression. The analysis is based on an original algorithm for calculation of spectral asymmetry index (SASI). The paper provides implementation details of

Maksim Jenihhin; Maksim Gorev; Vadim Pesonen; Dmitri Mihhailov; Peeter Ellervee; Hiie Hinrikus; Maie Bachmann; Jaanus Lass



Cognitive neuroscience of creativity: EEG based approaches  

Microsoft Academic Search

Cognitive neuroscience of creativity has been extensively studied using non-invasive electrical recordings from the scalp called electroencephalograms (EEGs) and event related potentials (ERPs). The paper discusses major aspects of performing research using EEG\\/ERP based experiments including the recording of the signals, removing noise, estimating ERP signals, and signal analysis for better understanding of the neural correlates of processes involved in

Narayanan Srinivasan



Independent component analysis for EEG source localization  

Microsoft Academic Search

We consider a spatiotemporal method for source localization, taking advantage of the entire EEG time series to reduce the configuration space we must evaluate. The EEG data are first decomposed into signal and noise subspaces using a principal component analysis (PCA) decomposition. This partitioning allows us to easily discard the noise subspace, which has two primary benefits: the remaining signal

Leonid Zhukov; David Weinstein; C. Johnson



Abnormal fronto-parietal coupling of brain rhythms in mild Alzheimer's disease: a multicentric EEG study.  


Cholinergic deafferentation/recovery in rats mainly impinges on the fronto-parietal coupling of brain rhythms [D. P. Holschneider et al. (1999) Exp. Brain Res., 126, 270-280]. Is this reflected by the functional coupling of fronto-parietal cortical rhythms at an early stage of Alzheimer's disease (mild AD)? Resting electroencephalographic (EEG) rhythms were studied in 82 patients with mild AD and in control subjects, such as 41 normal elderly (Nold) subjects and 25 patients with vascular dementia (VaD). Patients with AD and VaD had similar mini-mental state evaluation scores of 17-24. The functional coupling was estimated by means of the synchronization likelihood (SL) of the EEG data at electrode pairs, accounting for linear and non-linear components of that coupling. Cortical 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), beta 2 (20-30 Hz) and gamma (30-40 Hz). A preliminary data analysis (Nold) showed that surface Laplacian transformation of the EEG data reduced the values of SL, possibly because of the reduction of influences due to head volume conduction. Therefore, the final analysis was performed on Laplacian-transformed EEG data. The SL was dominant at alpha 1 band in all groups. Compared with the Nold subjects, patients with VaD and mild AD presented a marked reduction of SL at both fronto-parietal (delta-alpha) and inter-hemispherical (delta-beta) electrode pairs. The feature distinguishing the patients with mild AD with respect to patients with VaD groups was a more prominent reduction of fronto-parietal alpha 1 SL. These results suggest that mild AD is characterized by an abnormal fronto-parietal coupling of the dominant human cortical rhythm at 8-10.5 Hz. PMID:15128412

Babiloni, Claudio; Ferri, Raffaele; Moretti, Davide V; Strambi, Andrea; Binetti, Giuliano; Dal Forno, Gloria; Ferreri, Florinda; Lanuzza, Bartolo; Bonato, Claudio; Nobili, Flavio; Rodriguez, Guido; Salinari, Serenella; Passero, Stefano; Rocchi, Raffaele; Stam, C J; Rossini, Paolo M



Dissociative mental States are canonically associated with decreased temporal theta activity on spectral analysis of EEG.  


Quantitative electroencephalographic (QEEG) changes relating to dissociative experiences have only rarely been demonstrated, and dissociative states were not quantified in those studies. The aim of this study was to explore concurrent associations between quantified dissociative states and QEEG spectral parameters, in particular theta activity, in psychiatric patients. Fifty psychiatric patients completed the State Scale of Dissociation (SSD) immediately after a 15-min EEG recording. The EEG was assessed by conventional clinical visual analysis as well as by quantitative (QEEG) spectral analysis. Canonical analysis was performed between the set of SSD subscale scores and the following QEEG parameters: alpha-theta magnitude ratios, and relative as well as absolute theta magnitude obtained from right and left mid- to posterior-temporal and parieto-occipital derivations. The SSD transferred well to the present data in terms of reliability and internal criterion-related validity. The SSD and Dissociative Experiences Scale (DES) correlated significantly (r = .73, p < .001). Conventional EEG analysis identified 29 EEGs (58%) as abnormal. The main abnormality in 23 EEGs was slowing, maximal temporally in half of these cases. Canonical analyses confirmed a statistically significant relationship between the dissociation variables (especially conversion and depersonalization symptoms) and the QEEG variables (especially relative theta magnitude in the temporal regions; R = .72, p = .03, for SSD-QEEG; and R = .66, p = .04, for DES-QEEG). Quantified dissociative mental states are positively canonically associated with decreased temporal theta activity and increased alpha-theta ratios on QEEG in psychiatric patients with a high tendency to dissociate. The potential implications of the dissociation-theta-alpha relationship for understanding normal attentional processes need to be studied further. PMID:23796176

Krüger, Christa; Bartel, Peter; Fletcher, Lizelle



EEG dynamics reflects the partial and holistic effects in mental imagery generation*  

PubMed Central

Mental imagery generation is essential in the retrieval and storage of knowledge. Previous studies have indicated that the holistic properties of mental imagery generation can be evaluated more easily than the partial properties. However, the relationship between partial and holistic mental imagery generations has not been clearly demonstrated. To address this issue, we designed a task to investigate the changes in the spectrum of the electroencephalogram (EEG) during partial or holistic imagery generation. EEG signals were obtained from 18 healthy subjects, and a statistical measure of spectral dynamics between two EEG signals in per frequency band was performed. Additionally, a bicoherence spectrum analysis was used to detect the phase coupling within these two imagery conditions. Our results indicated that EEG of the partial imagery appeared earlier and stronger than that of the holistic imagery in the theta (5–8 Hz) range in a time window around 220 to 300 ms after cue onset, and a slight decrease in the alpha (8–12 Hz) band was observed at around 270 ms. The scalp topography of these changes in the theta and alpha bands distributed overall significantly in the frontal and central-temporal areas. The significant phase coupling within two conditions was remarkable at high frequency. From these results, we infer that there are complex relations between partial and holistic imageries. The generation of partial mental imagery is not a subprocess of holistic imagery, but it is relevant to holistic imagery and requires correct modification from the holistic information.

Li, Jian; Tang, Yi-yuan; Zhou, Li; Yu, Qing-bao; Li, Song; Sui, Dan-ni



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

ERIC Educational Resources Information Center

|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.…

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



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

ERIC Educational Resources Information Center

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.…

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



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

ERIC Educational Resources Information Center

|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…

Jausovec, Norbert



Comparison of Linear and Nonlinear Methods for EEG Signal Classification  

Microsoft Academic Search

The reliable operation of brain-computer inter- faces (BCI's) based on spontaneous electro electroencephalogram (EEG) signals requires accurate classification of multichannel EEG. The design of EEG representations and classifiers for BCI are open research questions whose difficulty stems from the need to extract complex spatial and temporal patterns from noisy mul- tidimensional time series obtained from EEG measurements. It is possible

Deon Garrett; David A. Peterson; Charles W. Anderson; Michael H. Thaut


Evoked EEG patterns during burst suppression with propofol  

Microsoft Academic Search

Background. During EEG suppression with isoflurane or sevoflurane anaesthesia, median nerve stimulation causes cortical responses of two kinds: an N20 wave with a latency of 20 ms and an EEG burst with a latency of 200 ms. We tested the possibility that median nerve stimula- tion during EEG suppression with propofol would cause an EEG response that was consistent enough

A.-M. Huotari; M. Koskinen; K. Suominen; S. Alahuhta; R. Remes; K. M. Hartikainen; V. Jantti




Microsoft Academic Search

This article introduces the reader to the EEG via a literature review and then presents data from a study that uses television commercials to modify EEG. Data show correlations between level of EEG activity and several measures of learning and affect. Further analysis presents a method to evaluate EEG change across half-second increments of the commercial. Speculations are made as




EEG findings in fetal alcohol syndrome and Down syndrome children  

Microsoft Academic Search

Results from previous studies evaluating the electroencephalograms (EEGs) of infants bom to alcoholic mothers suggest that the neonatal EEG may be a sensitive measure of prenatal ethanol exposure. Few studies, however, have examined EEG records of adolescent children with fetal alcohol syndrome (FAS). The present study investigated the resting EEG recordings of 18 matched triads of FAS, Down syndrome, and

W. M. Kaneko; E. L. Phillips; E. P. Riley; C. L. Ehlers



Subclinical rhythmic EEG discharge of adults: SREDA in two children.  


Subclinical rhythmic electroencephalogram (EEG) discharge is an uncommon rhythmic EEG pattern that has been reported to occur in adults. It is thought to be a nonspecific finding with little clinical significance. This article reports this EEG pattern in two children and suggests it be called subclinical rhythmic EEG discharge of adults and children. PMID:11377110

Nagarajan, L; Gregory, P B; Hewitt, I K; Gubbay, S S; Parry, T S



Spectral EEG frontal asymmetries correlate with the experienced pleasantness of TV commercial advertisements.  


The aim of this research is to analyze the changes in the EEG frontal activity during the observation of commercial videoclips. In particular, we aimed to investigate the existence of EEG frontal asymmetries in the distribution of the signals' power spectra related to experienced pleasantness of the video, as explicitly rated by the eleven experimental subjects investigated. In the analyzed population, maps of Power spectral density (PSD) showed an asymmetrical increase of theta and alpha activity related to the observation of pleasant (unpleasant) advertisements in the left (right) hemisphere. A correlation analysis revealed that the increase of PSD at left frontal sites is negatively correlated with the degree of pleasantness perceived. Conversely, the de-synchronization of left alpha frontal activity is positively correlated with judgments of high pleasantness. Moreover, our data presented an increase of PSD related to the observation of unpleasant commercials, which resulted higher with respect to the one elicited by pleasant advertisements. PMID:21327841

Vecchiato, Giovanni; Toppi, Jlenia; Astolfi, Laura; De Vico Fallani, Fabrizio; Cincotti, Febo; Mattia, Donatella; Bez, Francesco; Babiloni, Fabio



Visual evoked responses, EEG's and reaction time during a normoxic saturation dive, NISAT I.  


Three Navy divers were exposed to a normoxic breathing mixture at 7.0 ATA for seven consecutive days. Visual evoked responses (VER's), electroencephalograms (EEG's) and simple reaction time (RT) were measured. Previously reported amplitude decreases in a VER to a flash rate of 1 Hz (VER 1) and to a flash rate of 16 Hz (VER 16) were again found during this dive. The variability of the VER 16 and the latency of the VER 1 also increased during the saturation period. In the EEG analysis, changes in the amplitude of both alpha and theta were found, as were decreases in alpha frequency. The RT task showed a marked elevation of response time at the beginning of the dive period which gradually returned to predive levels. Latency of the VER 160-180 ms component was highly correlated with the changes in RT. The results are discussed in terms of information processing and cerebral dysfunction. PMID:878068

Mckay, C L; Strauss, M S; Kinney, J A; Luria, S M



Scalp EEG does not predict hemispherectomy outcome  

PubMed Central

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.

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



Investigation into Stress of Mothers with Mental Retardation Children Based on EEG (Electroencephalography) and Psychology Instruments  

Microsoft Academic Search

\\u000a This paper proposed a new method, combining EEG and psychology instruments, to detect stress which can contribute in prediction\\u000a and intervention of major depression. Seven mothers with mental retardation children as stress group and four age-matched\\u000a mothers with healthy children as normal controls are enlisted. Results showed that relative power in alpha rhythm of stress\\u000a group is significantly less than

Wen Zhao; Li Liu; Fang Zheng; Dangping Fan; Xuebin Chen; Yongxia Yang; Qingcui Cai


Quantified EEG in different G situations  

NASA Astrophysics Data System (ADS)

The electrical activity of the brain (EEG) has been recorded during parabolic flights in trained astronauts and non trained volunteers as well. The Fast Fourier analysis of the EEG activity evidenced more asymmetry between the two brain hemispheres in the subjects who suffered from motion sickness than in the others. However, such a FFT classification does not lead to a discrimination between deterministic and stochastic events. Therefore, a first attempt was made to calculate the dimensionality of "chaotic attractors" in the EEG patterns as a function of the different g-epochs of one parabola. Very preliminary results are given here.

de Metz, K.; Quadens, O.; De Graeve, M.


Neural network model of cortical EEG response to olfactory stimuli  

NASA Astrophysics Data System (ADS)

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 descent.

Dunbar, George L.; van Toller, Steve



Somatosensory-Evoked Spikes on Electroencephalography (EEG): Longitudinal Clinical and EEG Aspects in 313 Children  

Microsoft Academic Search

Somatosensory-evoked spikes (ESp) are high-voltage potentials registered on the EEG, which accompany each of the percussions on the feet or hands. The objective of this research was to study the longitudinal clinical and EEG aspects of children with ESp. A total of 313 children, 53.7% male, showing ESp on the EEG and with an average initial age of 6.82 (range

Lineu Corrêa Fonseca; Gloria M. A. S. Tedrus





... is also used to: Evaluate problems with sleep ( sleep disorders ) Investigate periods of unconsciousness Monitor the brain during ... cases) Seizure disorder (such as epilepsy or convulsions ) Sleep disorder (such as narcolepsy ) Swelling of the brain ( encephalitis ) ...


Alzheimer's disease qEEG: spectral analysis versus coherence. Which is the best measurement?  


There is evidence in electroencephalography that alpha, theta and delta band oscillations reflect cognitive and memory performances and that quantitative techniques can improve the electroencephalogram (EEG) sensitivity. This paper presents the results of comparative analysis of qEEG variables as reliable markers for Alzheimer's disease (AD). We compared the sensitivity and specificity between spectral analysis (spectA) and coherence (Coh) within the same group of AD patients. SpectA and Coh were calculated from EEGs of 40 patients with mild to moderate AD and 40 healthy elderly controls. The peak of spectA was smaller in the AD group than in controls. AD group showed predominance of slow spectA in theta and delta bands and a significant reduction of inter-hemispheric Coh for occipital alpha 2 and beta 1 and for frontal delta sub-band. ROC curve supported that alpha band spectA was more sensitive than coherence to differentiate controls from AD. PMID:22297870

Anghinah, Renato; Kanda, Paulo Afonso Medeiros; Lopes, Helder Frederico; Basile, Luis Fernando Hindi; Machado, Sérgio; Ribeiro, Pedro; Velasques, Bruna; Sameshima, Koichi; Takahashi, Daniel Yasumasa; Pinto, Lécio Figueira; Caramelli, Paulo; Nitrini, Ricardo



The Sleep EEG as a Marker of Intellectual Ability in School Age Children  

PubMed Central

Study Objectives: To investigate the within-subject stability in the sleep EEG and the association between the sleep EEG and intellectual abilities in 9- to 12-year-old children. Design: Intellectual ability (WISC-IV, full scale, fluid, and verbal IQ, working memory, speed of processing) were examined and all-night polysomnography was performed (2 nights per subject). Setting: Sleep laboratory. Participants: Fourteen healthy children (mean age 10.5 ± 1.0 years; 6 girls). Measurements and Results: Spectral analysis was performed on artifact-free NREM sleep epochs (C3/A2). To determine intra-individual stability and inter-individual variability of the sleep EEG, power spectra were used as feature vectors for the estimation of Euclidean distances, and intraclass correlation coefficients (ICC) were calculated for the 2 nights. Sleep spindle peaks were identified for each individual and individual sigma band power was determined. Trait-like aspects of the sleep EEG were observed for sleep stage variables and spectral power. Within-subject distances were smaller than between-subject distances and ICC values ranged from 0.72 to 0.96. Correlations between spectral power in individual frequency bins and intelligence scores revealed clusters of positive associations in the alpha, sigma, and beta range for full scale IQ, fluid IQ, and working memory. Similar to adults, sigma power correlated with full scale (r = 0.67) and fluid IQ (r = 0.65), but not with verbal IQ. Spindle peak frequency was negatively related to full scale IQ (r = ?0.56). Conclusions: The sleep EEG during childhood shows high within-subject stability and may be a marker for intellectual ability. Citation: Geiger A; Huber R; Kurth S; Ringli M; Jenni OG; Achermann P. The sleep EEG as a marker of intellectual ability in school age children. SLEEP 2011;34(2):181-189.

Geiger, Anja; Huber, Reto; Kurth, Salome; Ringli, Maya; Jenni, Oskar G.; Achermann, Peter



Paradox lost? Exploring the role of alpha oscillations during externally vs. internally directed attention and the implications for idling and inhibition hypotheses  

Microsoft Academic Search

Although slow waves of the electroencephalogram (EEG) have been associated with attentional processes, the functional significance of the alpha component in the EEG (8.1–12 Hz) remains uncertain. Conventionally, synchronisation in the alpha frequency range is taken to be a marker of cognitive inactivity, i.e. ‘cortical idling’. However, it has been suggested that alpha may index the active inhibition of sensory

Nicholas R Cooper; Rodney J Croft; Samuel J. J Dominey; Adrian P Burgess; John H Gruzelier



Graph theoretical analysis of EEG functional connectivity during music perception.  


The present study evaluated the effect of music on large-scale structure of functional brain networks using graph theoretical concepts. While most studies on music perception used Western music as an acoustic stimulus, Guqin music, representative of Eastern music, was selected for this experiment to increase our knowledge of music perception. Electroencephalography (EEG) was recorded from non-musician volunteers in three conditions: Guqin music, noise and silence backgrounds. Phase coherence was calculated in the alpha band and between all pairs of EEG channels to construct correlation matrices. Each resulting matrix was converted into a weighted graph using a threshold, and two network measures: the clustering coefficient and characteristic path length were calculated. Music perception was found to display a higher level mean phase coherence. Over the whole range of thresholds, the clustering coefficient was larger while listening to music, whereas the path length was smaller. Networks in music background still had a shorter characteristic path length even after the correction for differences in mean synchronization level among background conditions. This topological change indicated a more optimal structure under music perception. Thus, prominent small-world properties are confirmed in functional brain networks. Furthermore, music perception shows an increase of functional connectivity and an enhancement of small-world network organizations. PMID:22982591

Wu, Junjie; Zhang, Junsong; Liu, Chu; Liu, Dongwei; Ding, Xiaojun; Zhou, Changle



Projection versus prewhitening for EEG interference suppression.  


Suppression of strong, spatially correlated background interference is a challenge associated with electroencephalography (EEG) source localization problems. The most common way of dealing with such interference is through the use of a prewhitening transformation based on an estimate of the covariance of the interference plus noise. This approach is based on strong assumptions regarding temporal stationarity of the data, which do not commonly hold in EEG applications. In addition, prewhitening cannot typically be implemented directly due to ill conditioning of the covariance matrix, and ad hoc regularization is often necessary. Using both simulation examples and experiments involving real EEG data with auditory evoked responses, we demonstrate that a straightforward interference projection method is significantly more robust than prewhitening for EEG source localization. PMID:22333979

Wu, Shun Chi; Swindlehurst, A Lee; Wang, Po T; Nenadic, Zoran



EEG in Cognitive Process and Dysfunction.  

National Technical Information Service (NTIS)

Meaning-related ERP difference in receptive language processing and feasibility of using scalp recorded EEG data in neurophysiology of language processing were studied. Results indicate that ERP differences are largest over the left hemisphere, particular...

W. S. Brown



Seizure prediction using EEG spatiotemporal correlation structure.  


A seizure prediction algorithm is proposed that combines novel multivariate EEG features with patient-specific machine learning. The algorithm computes the eigenspectra of space-delay correlation and covariance matrices from 15-s blocks of EEG data at multiple delay scales. The principal components of these features are used to classify the patient's preictal or interictal state. This is done using a support vector machine (SVM), whose outputs are averaged using a running 15-minute window to obtain a final prediction score. The algorithm was tested on 19 of 21 patients in the Freiburg EEG data set who had three or more seizures, predicting 71 of 83 seizures, with 15 false predictions and 13.8 h in seizure warning during 448.3 h of interictal data. The proposed algorithm scales with the number of available EEG signals by discovering the variations in correlation structure among any given set of signals that correlate with seizure risk. PMID:23041171

Williamson, James R; Bliss, Daniel W; Browne, David W; Narayanan, Jaishree T



Asthma phenotypes  

Microsoft Academic Search

The many roads leading to the syndrome of asthma have proven to be intricately interconnected. The chronic inflammation of\\u000a asthma is characterized by airway hyperreactivity and variable reversibility. Past classification systems relied on assessment\\u000a of daily impairment and the distinction between intrinsic (nonallergic) and extrinsic (allergic). With more precise asthma\\u000a phenotypes, association studies likely will have greater significance. In addition,

Steve Handoyo; Lanny J. Rosenwasser



Sleep EEG Provides Biomarkers in Depression  

Microsoft Academic Search

Patients with depression frequently report impaired sleep. Objective sleep is recorded by sleep electroencephalogram (EEG).\\u000a Characteristic sleep-EEG changes in affective disorders include disinhibition of rapid-eye-movement (REM) sleep (shortened\\u000a REM latency, prolonged first REM periods, elevated REM density, and a measure of the amount of REMs), impaired sleep continuity\\u000a and changes of nonREM sleep (decreases of slow wave sleep and stage

Mayumi Kimura; Axel Steiger


EEG-Based Personalized Digital Experience  

Microsoft Academic Search

\\u000a To make human computer interfaces more immersive and intuitive, a new dimension could be added. Real-time brain state recognition\\u000a from EEG including emotion recognition and level of concentration recognition would make an access to information more adaptive\\u000a and personalized. Modern EEG techniques give us an easy and portable way to monitor brain activities by using suitable signal\\u000a processing and classification

Olga Sourina; Yisi Liu; Qiang Wang; Minh Khoa Nguyen


Short-Term EEG Spectral Pattern as a Single Event in EEG Phenomenology  

PubMed Central

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, cognitive task and with different neuropsychopathologies is demonstrated.

Fingelkurts, Al. A; Fingelkurts, An. A



Sensitivity distributions of EEG and MEG measurements.  


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

Malmivuo, J; Suihko, V; Eskola, H



EEG and the variance of motor evoked potential amplitude.  


The motor threshold is an important parameter in selecting the treatment intensity of patients undergoing transcranial magnetic stimulation. The large variance in magnitude of motor evoked responses has forced clinicians to perform many trials and average the results to find a repeatable value for motor threshold. Our objective is to investigate the source of the variance in amplitude. Four clinically healthy adult males participated in an EEG and EMG during transcranial magnetic stimulation of the left motor cortex, 100% motor threshold, 0.1 Hz. Per our hypothesis, a significant negative correlation of .22 was found between the amplitude of the motor evoked potential and the power in the high alpha frequency band during the pre-stimulus period (p < .001). In addition, a significant positive correlation of .17 was found between the motor evoked potential (MEP) amplitude and the gamma band (p < .001). The strongest correlation of .27 (p < .001) was found between the MEP amplitude and the ratio of the power in the low gamma to high alpha band. We conclude that the gamma to alpha power ratio may be a useful indicator of cortical excitability. PMID:16929713

Zarkowski, P; Shin, C J; Dang, T; Russo, J; Avery, D



Spatial and temporal EEG dynamics of dual-task driving performance  

PubMed Central

Background Driver distraction is a significant cause of traffic accidents. The aim of this study is to investigate Electroencephalography (EEG) dynamics in relation to distraction during driving. To study human cognition under a specific driving task, simulated real driving using virtual reality (VR)-based simulation and designed dual-task events are built, which include unexpected car deviations and mathematics questions. Methods We designed five cases with different stimulus onset asynchrony (SOA) to investigate the distraction effects between the deviations and equations. The EEG channel signals are first converted into separated brain sources by independent component analysis (ICA). Then, event-related spectral perturbation (ERSP) changes of the EEG power spectrum are used to evaluate brain dynamics in time-frequency domains. Results Power increases in the theta and beta bands are observed in relation with distraction effects in the frontal cortex. In the motor area, alpha and beta power suppressions are also observed. All of the above results are consistently observed across 15 subjects. Additionally, further analysis demonstrates that response time and multiple cortical EEG power both changed significantly with different SOA. Conclusions This study suggests that theta power increases in the frontal area is related to driver distraction and represents the strength of distraction in real-life situations.



Relationship between Speed and EEG Activity during Imagined and Executed Hand Movements  

PubMed Central

The relationship between primary motor cortex and movement kinematics has been shown in nonhuman primate studies of hand reaching or drawing tasks. Studies have demonstrated that the neural activities accompanying or immediately preceding the movement encode the direction, speed and other information. Here we investigated the relationship between the kinematics of imagined and actual hand movement, i.e. the clenching speed, and the EEG activity in ten human subjects. Study participants were asked to perform and imagine clenching of the left hand and right hand at various speeds. The EEG activity in the alpha (8 Hz – 12 Hz) and beta (18 Hz – 28 Hz) frequency bands were found to be linearly correlated with the speed of imagery clenching. Similar parametric modulation was also found during the execution of hand movements. A single equation relating the EEG activity to the speed and the hand (left vs. right) was developed. This equation, which contained a linear independent combination of the two parameters, described the time-varying neural activity during the tasks. Based on the model, a regression approach was developed to decode the two parameters from the multiple-channel EEG signals. We demonstrated the continuous decoding of dynamic hand and speed information of the imagined clenching. In particular, the time-varying clenching speed was reconstructed in a bell-shaped profile. Our findings suggest an application to providing continuous and complex control of non-invasive brain-computer interface for movement-impaired paralytics.

Yuan, Han; Perdoni, Christopher; He, Bin



EEG gamma coherence and other correlates of subjective reports during ayahuasca experiences.  


The current study examined QEEG power and coherence of ayahuasca experiences with two experienced participants in a Brazilian jungle setting. An exploratory case series design was adopted for naturalistic field research. EEGs recorded during visual imagery was compared to eyes-closed baselines. The most important findings were increases in global EEG coherence in the 36-44 Hz and 50-64 Hz frequency bands for both subjects. Widely distributed cortical hyper-coherence seems reasonable given the intense synesthesia during ayahuasca experiences. Other findings include increased modal EEG alpha frequency and global power decreases across the cortex in most frequency bands, which concur with the EEG of psychedelics literature. Exploratory analysis revealed the usefulness of analyzing single Hz bins over the standard wide-band analysis. The discovery-oriented naturalistic approach developed for this study resulted in potentially important findings. We believe that finding increases in global gamma coherence during peak psychedelic experiences might contribute to the discussion of binding theory. Also, in light of recent research with gamma coherence during advanced meditative conditions, our findings might further the comparison of shamanic psychedelic practices with meditation. PMID:16149330

Stuckey, David E; Lawson, Robert; Luna, Luis Eduardo



Effects of 50 Hz electromagnetic fields on electroencephalographic alpha activity, dental pain threshold and cardiovascular parameters in humans  

Microsoft Academic Search

Recent studies indicate that exposure to extremely low frequency magnetic fields (ELF MFs) influences human electroencephalographic (EEG) alpha activity and pain perception. In the present study we analyse the effect on electrical EEG activity in the alpha band (8–13Hz) and on nociception in 40 healthy male volunteers after 90-min exposure of the head to 50Hz ELF MFs at a flux

Sergio Ghione; Cristina Del Seppia; Lorena Mezzasalma; Luca Bonfiglio



Cortical and hippocampal EEG effects of neurotransmitter agonists in spontaneously hypertensive vs. kainate-treated rats.  


To analyze mediatory mechanisms underlying attention-deficit hyperactivity disorder (ADHD) and their association with epilepsy, the electroencephalogram (EEG) responses to various centrally applied neurotransmitter agonists were studied in spontaneously hypertensive (SH), kainate-treated (KA), and normotensive (control) rats, with chronically implanted electrodes into the frontal cortex and hippocampus and a cannula into the lateral cerebral ventricle. In SH rats, the baseline EEG showed increased delta and beta2 activity in the hippocampus and decreased alpha/beta1 activity in both brain areas. In KA rats, these delta and alpha/beta1 effects were observed 2 weeks post-kainate, while the beta2 activity increase occurred after 5 weeks in the hippocampus and, to a greater extent, 9 weeks post-injection in both brain areas. In SH rats, NMDA increased delta and decreased alpha/beta1 activity, similar to KA rats 5 weeks post-injection. In SH rats, clonidine augmented theta/beta2 increase in the cortex and alpha suppression in both brain areas, in parallel with induction of beta2 activity in the hippocampus. These beta2 effects were observed 5 and 9 weeks post-kainate. In SH rats, baclofen produced robust delta/theta enhancement and alpha/beta1 suppression in both brain areas, with additional beta2 activity increase in the hippocampus, while muscimol was ineffective in both groups of rats. In KA rats, EEG responses to GABA agonists were similar to those in control. Our results demonstrate sensitization of NMDA receptors and ?2-adrenoceptors both in SH and KA rats and that of GABAb receptors specifically in SH rats. PMID:21300040

Vorobyov, Vasily; Schibaev, Nikolai; Kaptsov, Vladimir; Kovalev, Georgii; Sengpiel, Frank



Impact of regular meditation practice on EEG activity at rest and during evoked negative emotions.  


The main objective of the present investigation was to examine how long-term meditation practice is manifested in EEG activity under conditions of non-emotional arousal (eyes-closed and eyes-open periods, viewing emotionally neutral movie clip) and while experiencing experimentally induced negative emotions (viewing aversive movie clip). The 62-channel EEG was recorded in age-matched control individuals (n=25) and Sahaja Yoga meditators (SYM, n=25). Findings from the non-emotional continuum show that at the lowest level of arousal (eyes closed) SYM manifested larger power values in theta-1 (4-6 Hz), theta-2 (6-8 Hz) and alpha-1 (8-10 Hz) frequency bands. Although increasing arousal desynchronized activity in these bands in both groups, the theta-2 and alpha-1 power in the eyes-open period and alpha-1 power while viewing the neutral clip remained still higher in the SYM. During eyes-closed and eyes-open periods the controls were marked by larger right than left hemisphere power, indexing relatively more active left hemisphere parieto-temporal cortex whereas meditators manifested no hemisphere asymmetry. When contrasted with the neutral, the aversive movie clip yielded significant alpha desynchronization in both groups, reflecting arousing nature of emotional induction. In the control group along with alpha desynchronization affective movie clip synchronized gamma power over anterior cortical sites. This was not seen in the SYM. Overall, the presented report emphasizes that the revealed changes in the electrical brain activity associated with regular meditation practice are dynamical by nature and depend on arousal level. The EEG power findings also provide the first empirical proof of a theoretical assumption that meditators have better capabilities to moderate intensity of emotional arousal. PMID:16019582

Aftanas, Ljubomir; Golosheykin, Semen



A novel method based on realistic head model for EEG denoising  

Microsoft Academic Search

It is necessary to remove the noise in EEG before further EEG analysis and processing. For EEG is deeply masked in the noise background, it is very difficult to denoise EEG effectively. Proposed in this paper is a novel realistic head model based sparse decomposition algorithm to denoise EEG, which is an iterative procedure combining the subject's physiology of EEG

Peng Xu; Dezhong Yao



Instantaneous frequency based newborn EEG seizure characterisation  

NASA Astrophysics Data System (ADS)

The electroencephalogram (EEG), used to noninvasively monitor brain activity, remains the most reliable tool in the diagnosis of neonatal seizures. Due to their nonstationary and multi-component nature, newborn EEG seizures are better represented in the joint time-frequency domain than in either the time domain or the frequency domain. Characterising newborn EEG seizure nonstationarities helps to better understand their time-varying nature and, therefore, allow developing efficient signal processing methods for both modelling and seizure detection and classification. In this article, we used the instantaneous frequency (IF) extracted from a time-frequency distribution to characterise newborn EEG seizures. We fitted four frequency modulated (FM) models to the extracted IFs, namely a linear FM, a piecewise-linear FM, a sinusoidal FM, and a hyperbolic FM. Using a database of 30-s EEG seizure epochs acquired from 35 newborns, we were able to show that, depending on EEG channel, the sinusoidal and piecewise-linear FM models best fitted 80-98% of seizure epochs. To further characterise the EEG seizures, we calculated the mean frequency and frequency span of the extracted IFs. We showed that in the majority of the cases (>95%), the mean frequency resides in the 0.6-3 Hz band with a frequency span of 0.2-1 Hz. In terms of the frequency of occurrence of the four seizure models, the statistical analysis showed that there is no significant difference( p = 0.332) between the two hemispheres. The results also indicate that there is no significant differences between the two hemispheres in terms of the mean frequency ( p = 0.186) and the frequency span ( p = 0.302).

Mesbah, Mostefa; O'Toole, John M.; Colditz, Paul B.; Boashash, Boualem



Alpha Thalassemia  


Alpha Thalassemia ? Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect on the anemia. Normal alpha globin genes found on ...


Directional information flows between brain hemispheres across waking, non-REM and REM sleep states: an EEG study.  


The present electroencephalographic (EEG) study evaluated the hypothesis of a preferred directionality of communication flows between brain hemispheres across 24 h (i.e., during the whole daytime and nighttime), as an extension of a recent report showing changes in preferred directionality from pre-sleep wake to early sleep stages. Scalp EEGs were recorded in 10 normal volunteers during daytime wakefulness (eyes closed; first period: from 10:00 to 13:00 h; second period: from 14:00 to 18:00 h; third period: from 19:00 to 22:00 h) and nighttime sleep (four NREM-REM cycles). EEG rhythms of interest were delta (1-4 Hz), theta (5-7 Hz), alpha (8-11 Hz), sigma (12-15 Hz) and beta (16-28 Hz). The direction of the inter-hemispheric information flow was evaluated by computing the directed transfer function (DTF) from these EEG rhythms. Inter-hemispheric directional flows varied as a function of the state of consciousness (wake, NREM sleep, REM sleep) and in relation to different cerebral areas. During the daytime, alpha and beta rhythms conveyed inter-hemispheric signals with preferred Left-to-Right hemisphere direction in parietal and central areas, respectively. During the NREM sleep periods of nighttime, the direction of inter-hemispheric DTF information flows conveyed by central beta rhythms was again preponderant from Left-to-Right hemisphere in the stage 2, independent of cortical areas. No preferred direction emerged across the REM periods. These results support the hypothesis that specific directionality of communication flows between brain hemispheres is associated with wakefulness, NREM (particularly stage 2) and REM states during daytime and nighttime. They also reinforce the suggestive hypothesis of a relationship between inter-hemispheric directionality of EEG functional coupling and frequency of the EEG rhythms. PMID:19121373

Bertini, Mario; Ferrara, Michele; De Gennaro, Luigi; Curcio, Giuseppe; Moroni, Fabio; Babiloni, Claudio; Infarinato, Francesco; Rossini, Paolo Maria; Vecchio, Fabrizio



[Study of diazepam with quantitative EEGs taken with eyes opened and topography].  


Diazepam is a representative drug of benzodiazepines. The subjects were 9 right-handed healthy male volunteers 21 25 years of age. Double blind crossover trials with placebo control were conducted in a random sequence at an interval of 1 week. Diazepam 10 mg and placebo were administered as single oral doses. Three-minute EEGs were recorded with subjects' eyes opened before and 2 h after drug administration. One-minute out of the 3-minute EEGs was analyzed with FFT, and the absolute amplitude power (microV) was calculated. These results were subjected to Student's t-test (double difference) and displayed with topographic maps (t statistic significance probability mapping). Diazepam decreased the delta absolute amplitude power over left-parietal dominance, theta absolute amplitude power diffusely and alpha absolute amplitude power over parietal region dominance. It also increased the beta absolute amplitude power over left-antero-temporal region dominance. The EEG profiles taken with subjects' eyes open were different from those of diazepam with eyes-closed vigilance controlled concerning the degree of decrease of delta and beta activities and region of the effect on alpha activity. PMID:9278939

Yamadera, H; Kato, M; Ueno, T; Suzuki, H; Nakamura, S; Okuma, T



Automatic classification of athletes with residual functional deficits following concussion by means of EEG signal using support vector machine.  


There is a growing body of knowledge indicating long-lasting residual electroencephalography (EEG) abnormalities in concussed athletes that may persist up to 10-year postinjury. Most often, these abnormalities are initially overlooked using traditional concussion assessment tools. Accordingly, premature return to sport participation may lead to recurrent episodes of concussion, increasing the risk of recurrent concussions with more severe consequences. Sixty-one athletes at high risk for concussion (i.e., collegiate rugby and football players) were recruited and underwent EEG baseline assessment. Thirty of these athletes suffered from concussion and were retested at day 30 postinjury. A number of task-related EEG recordings were conducted. A novel classification algorithm, the support vector machine (SVM), was applied as a classifier to identify residual functional abnormalities in athletes suffering from concussion using a multichannel EEG data set. The total accuracy of the classifier using the 10 features was 77.1%. The classifier has a high sensitivity of 96.7% (linear SVM), 80.0% (nonlinear SVM), and a relatively lower but acceptable selectivity of 69.1% (linear SVM) and 75.0% (nonlinear SVM). The major findings of this report are as follows: 1) discriminative features were observed at theta, alpha, and beta frequency bands, 2) the minimal redundancy relevance method was identified as being superior to the univariate t -test method in selecting features for the model calculation, 3) the EEG features selected for the classification model are linked to temporal and occipital areas, and 4) postural parameters influence EEG data set and can be used as discriminative features for the classification model. Overall, this report provides sufficient evidence that 10 EEG features selected for final analysis and SVM may be potentially used in clinical practice for automatic classification of athletes with residual brain functional abnormalities following a concussion episode. PMID:18701381

Cao, Cheng; Tutwiler, Richard Laurence; Slobounov, Semyon



Computer for Averaging Transients to Determine EEG Evoked Potentials.  

National Technical Information Service (NTIS)

A 'Computer for Averaging Transients' (CAT) has been designed, constructed, and tested; the CAT is capable of averaging overall electroencephalogram (EEG) patterns following repeated stimuli, thereby separating the EEG response waveform from the many unre...

F. Cruger



Comparison of ictal and interictal EEG signals using fractal features.  


The feature analysis of epileptic EEG is very significant in diagnosis of epilepsy. This paper introduces two nonlinear features derived from fractal geometry for epileptic EEG analysis. The features of blanket dimension and fractal intercept are extracted to characterize behavior of EEG activities, and then their discriminatory power for ictal and interictal EEGs are compared by means of statistical methods. It is found that there is significant difference of the blanket dimension and fractal intercept between interictal and ictal EEGs, and the difference of the fractal intercept feature between interictal and ictal EEGs is more noticeable than the blanket dimension feature. Furthermore, these two fractal features at multi-scales are combined with support vector machine (SVM) to achieve accuracies of 97.58% for ictal and interictal EEG classification and 97.13% for normal, ictal and interictal EEG classification. PMID:24156671

Wang, Yu; Zhou, Weidong; Yuan, Qi; Li, Xueli; Meng, Qingfang; Zhao, Xiuhe; Wang, Jiwen



Longitudinal Genetic Analysis of EEG Coherence in Young Twins  

Microsoft Academic Search

During middle childhood, continuous changes occur in electroencephalogram (EEG) coherence, an index of cortico-cortical connectivity of the brain. In the gradual development of EEG coher- ence, occasional \\

G. C. M. van Baal; D. I. Boomsma; E. J. C. de Geus



Pattern Recognition of EEG to Determine Level of Alertness.  

National Technical Information Service (NTIS)

This report documents the work accomplished during the second reporting period in applying the principles of pattern recognition technology to the analysis of EEG. Using EEG recordings, two sleep state classification systems, based on inputs derived from ...

W. B. Martin



Performance of beamformers on EEG source reconstruction.  


Recently a number of new beamformers have been introduced for reconstruction and localization of neural sources from EEG and MEG. However, little is known about the relative performance of these beamformers. In this study, 8 scalar beamformers were examined with respect to several parameters to determine how effective they are at reconstruction of a dipole time course from EEG. A simulated EEG signal was produced by means of forward head modelling for projection of an artificial dipole on scalp electrodes then superimposed on background signal. Both real EEG and white noise were applied as background activity. Although the eigenspace beamformer can perform slightly better than other beamformers for small dipoles, and even more so for large dipoles, it is not a contender for real-time beamforming of EEG as it cannot be completely automated. Overall, in terms of performance, robustness to variations in parameters, and ease of application, the minimum variance and Borgiotti-Kaplan beamformers were found to be the best performers. PMID:23366437

Jon Mohamadi, Yaqub; Poudel, Govinda; Innes, Carrie; Jones, Richard D



Coupling between Intrinsic Prefrontal HbO2 and Central EEG Beta Power Oscillations in the Resting Brain  

PubMed Central

There is increasing interest in the intrinsic activity in the resting brain, especially that of ultraslow and slow oscillations. Using near-infrared spectroscopy (NIRS), electroencephalography (EEG), blood pressure (BP), respiration and heart rate recordings during 5 minutes of rest, combined with cross spectral and sliding cross correlation calculations, we identified a short-lasting coupling (duration s) between prefrontal oxyhemoglobin (HbO2) in the frequency band between 0.07 and 0.13 Hz and central EEG alpha and/or beta power oscillations in 8 of the 9 subjects investigated. The HbO2 peaks preceded the EEG band power peaks by 3.7 s in 6 subjects, with moderate or no coupling between BP and HbO2 oscillations. HbO2 and EEG band power oscillations were approximately in phase with BP oscillations in the 2 subjects with an extremely high coupling (squared coherence ) between BP and HbO2 oscillation. No coupling was identified in one subject. These results indicate that slow precentral (de)oxyhemoglobin concentration oscillations during awake rest can be temporarily coupled with EEG fluctuations in sensorimotor areas and modulate the excitability level in the brains’ motor areas, respectively. Therefore, this provides support for the idea that resting state networks fluctuate with frequencies of between 0.01 and 0.1 Hz (Mantini PNAS 2007).

Pfurtscheller, Gert; Daly, Ian; Bauernfeind, Gunther; Muller-Putz, Gernot R.



Coupling between intrinsic prefrontal HbO2 and central EEG beta power oscillations in the resting brain.  


There is increasing interest in the intrinsic activity in the resting brain, especially that of ultraslow and slow oscillations. Using near-infrared spectroscopy (NIRS), electroencephalography (EEG), blood pressure (BP), respiration and heart rate recordings during 5 minutes of rest, combined with cross spectral and sliding cross correlation calculations, we identified a short-lasting coupling (duration [Formula: see text] s) between prefrontal oxyhemoglobin (HbO2) in the frequency band between 0.07 and 0.13 Hz and central EEG alpha and/or beta power oscillations in 8 of the 9 subjects investigated. The HbO2 peaks preceded the EEG band power peaks by 3.7 s in 6 subjects, with moderate or no coupling between BP and HbO2 oscillations. HbO2 and EEG band power oscillations were approximately in phase with BP oscillations in the 2 subjects with an extremely high coupling (squared coherence [Formula: see text]) between BP and HbO2 oscillation. No coupling was identified in one subject. These results indicate that slow precentral (de)oxyhemoglobin concentration oscillations during awake rest can be temporarily coupled with EEG fluctuations in sensorimotor areas and modulate the excitability level in the brains' motor areas, respectively. Therefore, this provides support for the idea that resting state networks fluctuate with frequencies of between 0.01 and 0.1 Hz (Mantini PNAS 2007). PMID:22937070

Pfurtscheller, Gert; Daly, Ian; Bauernfeind, Günther; Müller-Putz, Gernot R



Interictal quantitative EEG in migraine: a blinded controlled study  

Microsoft Academic Search

Abnormal electroencephalography (EEG) in migraineurs has been reported in several studies. However, few have evaluated EEG\\u000a findings in migraineurs during a time period when neither the last attack nor the next attack may interact with the results.\\u000a We, therefore, compared interictal EEG in migraineurs and headache-free subjects with a design controlled for interference\\u000a by pre-ictal changes. Pre-ictal EEG findings in

Marte Helene Bjørk; Lars J. Stovner; Morten Engstrøm; Marit Stjern; Knut Hagen; Trond Sand



EEG-Verlaufsuntersuchungen nach Carotis-interna-Angiographie  

Microsoft Academic Search

1.Successive EEG investigations were carried out on 22 patients with internal-carotid arteriography, and the type, extent, frequency and duration of post-arteriographic EEG changes were determined.2.Post-angiographic EEG changes were demonstrated in 19 out of the 22 patients (86.3%), without there being any clinically ascertainable deterioration in the neurological or psychical status.3.9 out of the 10 patients with normal pre-EEG pictures exhibited

W. Girke



EEG-Based Emotion Recognition in Music Listening  

Microsoft Academic Search

Ongoing brain activity can be recorded as electroen-cephalograph (EEG) to discover the links between emotional states and brain activity. This study applied machine-learning algorithms to categorize EEG dynamics according to subject self-reported emotional states during music listening. A framework was proposed to optimize EEG-based emotion recognition by systematically 1) seeking emotion-specific EEG features and 2) exploring the efficacy of the

Yuan-Pin Lin; Chi-Hong Wang; Tzyy-Ping Jung; Tien-Lin Wu; Shyh-Kang Jeng; Jeng-Ren Duann; Jyh-Horng Chen



A novel quantitative EEG injury measure of global cerebral ischemia  

Microsoft Academic Search

Objective: To develop a novel quantitative EEG (qEEG) based analysis method, cepstral distance (CD) and compare it to spectral distance (SD) in detecting EEG changes related to global ischemia in rats.Methods: Adult Wistar rats were subjected to asphyxic-cardiac arrest for sham, 1, 3, 5 and 7 min (n=5 per group). The EEG signal was processed and fitted into an autoregressive

R. G. Geocadin; R. Ghodadra; T. Kimura; H. Lei; D. L. Sherman; D. F. Hanley; N. V. Thakor



Recording of fast activity at the onset of partial seizures: depth EEG vs. scalp EEG.  


Rapid discharges (25-80 Hz), a characteristic EEG pattern often recorded at seizure onset in partial epilepsies, are often considered as electrophysiological signatures of the epileptogenic zone. While the recording of rapid discharges from intracranial electrodes has long been established, their observation from the scalp is challenging. The prevailing view is that rapid discharges cannot be seen clearly (or at all) in scalp EEG because they have low signal-to-noise ratio. To date, however, no studies have investigated the 'observability' of rapid discharges, i.e. under what conditions and to what extent they can be visible in recorded EEG signals. Here, we used a model-based approach to examine the impact of several factors (distance to sources, skull conductivity, source area, source synchrony, and background activity) on the observability of rapid discharges in simultaneously simulated depth EEG and scalp EEG signals. In our simulations, the rapid discharge was clearly present in depth EEG signals but mostly almost not visible in scalp EEG signals. We identified some of the factors that may limit the observability of the rapid discharge on the scalp. Notably, surrounding background activity was found to be the most critical factor. The findings are discussed in relation to the presurgical evaluation of epilepsy. PMID:22146749

Cosandier-Rimélé, D; Bartolomei, F; Merlet, I; Chauvel, P; Wendling, F



Genetics of alcoholism using intermediate phenotypes.  


This article represents the proceedings of a symposium at the 2002 meeting of the Research Society on Alcoholism in San Francisco, CA. It was organized by Mary-Anne Enoch and David Goldman and chaired by David Goldman. The presentations were (1) Two functional polymorphisms and their intermediate phenotypes in complex behaviors: COMT/executive cognition and anxiety and HTT/anxiety, by David Goldman; (2) Role of the EEG in determining genetic risk for alcoholism and anxiety disorders, by Mary-Anne Enoch; (3) The response to alcohol as an intermediate phenotype for alcoholism, by Marc A. Schuckit; and (4) Pharmacogenomic approaches to alcoholism treatment: toward a hypothesis, by Bankole A. Johnson. PMID:12605066

Enoch, Mary-Anne; Schuckit, Marc A; Johnson, Bankole A; Goldman, David



Study on Emotional Event-Related Potential by EEG Data  

Microsoft Academic Search

Electroencephalogram (EEG) activity in Male human during pleasant and unpleasant emotions by different events was investigated. When the subjects were listening to pleasant music and noise, the EEG data comparing pleasant and unpleasant states were obtained. Related emotional theta band was studied by using Principal Component Analysis of EEG data, meanwhile extracting the first principal component, the principal component loading

Fei Jiang; Zhihua Chen; Li Zhao; Safeng Zou



How reproducible is the topographical distribution of EEG amplitude?  

Microsoft Academic Search

If topographical EEG is to be a useful tool for localising cerebral processes, then the results of the same, or closely similar experiments, using different samples should yield similar results. Although the reliability of EEG is well established in other ways, there is little available data on the reproducibility of EEG topography across experiments. The aim of this study was

A Burgess; J Gruzelier



EEG\\/MEG brain mapping of human pain: recent advances  

Microsoft Academic Search

The scientific study of EEG and MEG brain mapping of human pain started around 25 years ago. Few progresses have been made on the quantitative analyses of the EEG power frequency effect on the brain in both clinical pain and laboratory-controlled studies. It shall be noted that the tonic states of on-going pain are best to be described by EEG

Andrew C. N Chen



Telemetered EEG in schizophrenia: spectral analysis during abnormal behaviour episodes  

Microsoft Academic Search

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

J R Stevens; A Livermore



Topographical EEG Mapping in a Case of Recurrent Sleep Terrors  

Microsoft Academic Search

Sleep terrors are characterized by marked CNS arousal and typically occur during stage 3-4 sleep within the first NREM cycle. Studies of the EEG during sleep terrors suggest that delta power and synchrony in the EEG may be important physiological markers of sleep terror presence and intensity. An EEG mapping study was undertaken with a single participant who experienced three

Antonio L. Zadra; Tore A. Nielsen



Automated EEG feature selection for brain computer interfaces  

Microsoft Academic Search

A brain computer interface (BCI) utilizes signals derived from electroencephalography (EEG) to establish a connection between a person's state of mind and a computer based signal processing system that interprets the EEG signals. The choice of suitable features of the available EEG signals is crucial for good BCI communication. The optimal set of features is strongly dependent on the subjects

Michael Schroder; Martin Bogdan; T. Hinterberger; N. Birbaumer



Genetic architecture of EEG power spectra in early life  

Microsoft Academic Search

We measured the electroencephalogram (EEG) in 209 5 year old monozygotic (MZ) and dizygotic (DZ) twin pairs to estimate the relative contribution of genetic and environmental factors to EEG power spectra in early life. Data from same-sex and from opposite-sex twin pairs were used to test for sex differences in genetic influences. Results showed high concordance for EEGs of MZ

G. C. M. Van Baal; E. J. C. De Geus; D. I. Boomsma



EEG Model and Location in Brain when Enjoying Music  

Microsoft Academic Search

The aim of this study was to confirm the character of EEG and the location in brain when a person was enjoying different rhythm music. It made the subjects excited when they enjoyed different rhythm music, the EEG signals are collected with Phoenix Digital EEG with 128 channels, and compared with the ones before the subjects enjoying the music. Obvious

Huisheng Lu; Mingshi Wang; Hongqiang Yu



Classification of EEG signals using the wavelet transform  

Microsoft Academic Search

The electroencephalogram (EEG) is widely used clinically to investigate brain disorders. However, abnormalities in the EEG in serious psychiatric disorders are at times too subtle to be detected using conventional techniques. This paper describes the application of an artificial neural network (ANN) technique together with a feature extraction technique, viz., the wavelet transform, for the classification of EEG signals. The

Neep Hazarika; Jean Zhu Chen; Ah Chung Tsoi; Alex Sergejew



EEG complexity measurement of focal ischemic cerebral injury  

Microsoft Academic Search

Based on a new focal cerebral ischemia experimental model using SD rats, the authors analyzed EEG complexity. They found that EEG complexity is very sensitive to the extent of focal ischemic cerebral injury. In addition ischemic and normal regions can be distinguished by analyzing their EEG complexities

Ji-Wu Zhang; Chong-Xun Zheng; Da-Zong Jiang



Heuristic real time feature extraction of the electroencephalogram (EEG)  

Microsoft Academic Search

The extremely complex nature of the electroencephalogram (EEG), and the subtle, nonquantified methods of pattern recognition used by human interpreters have made EEG analysis resistant to automation. Attempts at pattern recognition using multivariate classification procedures have not produced generalizable results due to the inadequate degree and quality of feature extraction prior to classification. A real time, on-line EEG analysis strategy

Alan S. Gevins; Charles L. Yeager; Stephen L. Diamond



Multiscale permutation entropy analysis of EEG recordings during sevoflurane anesthesia  

Microsoft Academic Search

Electroencephalogram (EEG) monitoring of the effect of anesthetic drugs on the central nervous system has long been used in anesthesia research. Several methods based on nonlinear dynamics, such as permutation entropy (PE), have been proposed to analyze EEG series during anesthesia. However, these measures are still single-scale based and may not completely describe the dynamical characteristics of complex EEG series.

Duan Li; Xiaoli Li; Zhenhu Liang; Logan J. Voss; Jamie W. Sleigh



Automated Estimation of Sedation depth from the EEG  

Microsoft Academic Search

A method is presented for the automatic determination of a patient's level of sedation from the EEG. Six bipolar channels of EEG recorded from 12 adult patients sedated with low-dose propofol (2, 6-disopropylphenol) were used to develop a linear discriminant based system for depth of sedation monitoring using a number of quantitative EEG measures. A cross fold validation estimate of

B. R. Greene; P. Mahon; B. McNamara; G. B. Boylan; G. Shorten



Error bounds for EEG and MEG dipole source localization  

Microsoft Academic Search

Summary General formulas are presented for computing a lower bound on localization and moment error for electroencephalographic (EEG) or magnetoencephalographic (MEG) current source dipole models with arbitrary sensor array geometry. Specific EEG and MEG formulas are presented for multiple dipoles in a head model with 4 spherical shells. Localization error bounds are presented for both EEG and MEG for several

John C. Mosher; Michael E. Spencer; Richard M. Leahy; Paul S. Lewis



The EEG analysis method for obtaining the feeling  

Microsoft Academic Search

The electroencephalogram (EEG), the brain activity of neurons in the brain, is used to record brain activity for many purposes. It also changes depends on mental conditions because mental conditions are generated in the brain. In this study, we try to estimate the mental conditions by observing the EEG patterns. The EEG data caused by mental changes is obtained as

Yohei Tomita; Shin-ichi Ito; Yasue Mitsukura



Vigilance detection based on sparse representation of EEG  

Microsoft Academic Search

Electroencephalogram (EEG) based vigilance detection of those people who engage in long time attention demanding tasks such as monotonous monitoring or driving is a key field in the research of brain-computer interface (BCI). However, robust detection of human vigilance from EEG is very difficult due to the low SNR nature of EEG signals. Recently, compressive sensing and sparse representation become

Hongbin Yu; Hongtao Lu; Tian Ouyang; Hongjun Liu; Bao-Liang Lu



A kind of on-off control method based on EEG dimension complexity detection  

NASA Astrophysics Data System (ADS)

Some studies show that Environment Control System (ECS) improves severe disabled people life, one of which is based on analyzing alpha wave following eye closure. This paper proposes a method for detecting the difference of dimension complexity between eye opening and eye closure. By modifying Grassberger and Procaccia algorithm for calculating correlation dimension, this improved method can process overlapped data segment effectively. The value, calculated by this method, is called EEG dimension complexity, which indicates the variability of brain function. Experiments show that EEG dimension complexity is suitable and precise to distinguish two states between eye opening and closure. New method decreases computational cost, and its application shows that this method can be used to control light switch on and off.

Wang, Hong; Li, Chunsheng; Zhao, Haibin; Liu, Chong



Spatio-Temporal Analysis of Frontal Midline Theta Rhythm in EEG during 3-D Maze Task  

NASA Astrophysics Data System (ADS)

We examined electroencephalography (EEG) power spectrum and complex coherence in the theta and alpha band while the subjects were performing a three - dimension (3-D) virtual maze navigation tasks. 10 healthy males participated. The imaginary part of coherency was used to provide a functional measurement of corticocortical communication. The imaginary part of coherency analysis applied to a measurement EEG data in the section which frontal midline theta rhythm (6 - 7 Hz) appeared during 3-D maze tasks. The results showed that the coherency in the theta band between regions of frontal and right temporal increased during 3-D maze tasks. This result suggests that the frontal midline theta rhythm modulate the component of the neural circuit, and greater connections between the cortex regions of the frontal - temporal increase during 3-D maze task. Therefore, this finding leads to conclusion that information processing in spatial navigation is related to regions of frontal and temporal.

Uehara, Yasuaki; Tanaka, Keita; Uchikawa, Yoshinori; Kim, Bong-Soo


Hemispheric specialization of language: an EEG study of bilingual Hopi indian children.  


Electroencephalographic (EEG) recordings were obtained from electrode placements over the left and right frontal and parietal lobes of the brain in sixteen Hopi Indian children listening to tape recorded children's stories in the Hopi and English languages. Spectral analysis of the EEG data revealed that, for the parietal leads, alpha desynchronization was relatively greater over the right hemisphere for listening to Hopi than for listening to English, which indicates a greater right hemisphere participation in the processing of the Hopi speech. The results of the experiment are directionally consistent with our hypothesis, and imply that linguistic relativity may exist on a neurolinguistic level, such that languages can differ in the relative degree to which they serve as instruments of thought in a propositional, left hemisphere mode, or in an appositional, right hemisphere mode. PMID:617618

Rogers, L; TenHouten, W; Kaplan, C D; Gardiner, M



[High resolution EEG and whole head MEG].  


A low-noise multichannel EEG-Amplifier-System has been designed and analyzed, which is electromagnetically compatible with SQUIDs. The EEG- together with the MEG-System is operated inside the quiet environment of a magnetically shielded room, hence no electrical 50 Hz-Artifact is detectable. Measurements pointed out that the influence of amplifier- and electrochemical-noise of electrodes to averaged EEG-spectral densities is less than 1% within the frequency range 0.5 to 70 Hz. Thermal noise of the skin-electrode-interface, equivalent to a resistor of 30 k omega, only begins to take effect above 20 Hz, suggesting that there is no need of skin abrasion. PMID:12465238

Scheer, H J; Burghoff, M



A Discriminative Approach to EEG Seizure Detection  

PubMed Central

Seizures are abnormal sudden discharges in the brain with signatures represented in electroencephalograms (EEG). The efficacy of the application of speech processing techniques to discriminate between seizure and non-seizure states in EEGs is reported. The approach accounts for the challenges of unbalanced datasets (seizure and non-seizure), while also showing a system capable of real-time seizure detection. The Minimum Classification Error (MCE) algorithm, which is a discriminative learning algorithm with wide-use in speech processing, is applied and compared with conventional classification techniques that have already been applied to the discrimination between seizure and non-seizure states in the literature. The system is evaluated on 22 pediatric patients multi-channel EEG recordings. Experimental results show that the application of speech processing techniques and MCE compare favorably with conventional classification techniques in terms of classification performance, while requiring less computational overhead. The results strongly suggests the possibility of deploying the designed system at the bedside.

Johnson, Ashley N.; Sow, Daby; Biem, Alain



Insights from Intermittent Binocular Rivalry and EEG  

PubMed Central

Novel stimulation and analytical approaches employed in EEG studies of ambiguous figures have recently been applied to binocular rivalry. The combination of intermittent stimulus presentation and EEG source imaging has begun to shed new light on the neural underpinnings of binocular rivalry. Here, we review the basics of the intermittent paradigm and highlight methodological issues important for interpreting previous results and designing future experiments. We then outline current analytical approaches, including EEG microstates, event-related potentials, and statistically based source estimation, and propose a neural model of the sequence of brain events that may underlie different aspects of binocular rivalry. Finally, we discuss the advantages and limitations of using binocular rivalry as a tool to investigate the neural basis of perceptual awareness.

Pitts, Michael A.; Britz, Juliane



A wireless multichannel EEG recording platform.  


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

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



Three methods compared for detecting the onset of alpha wave synchronization following eye closure  

Microsoft Academic Search

Recent work indicates that the variation in the occipital alpha wave component of the EEG spectrum, controlled through eye closure, can be used by an untrained person to effect reliable activation of electrical devices. Here we describe and compare three real-time strategies, based on analogue and digital signal processing methods, of detecting the onset of alpha wave synchronization during eye

L Kirkup; A Searle; A Craig; P McIsaac; G Larsen



Sex differences between the combined and inattentive types of attention-deficit/hyperactivity disorder: An EEG perspective.  


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 8-12years. Subject groups included 80AD/HD Combined type (40 boys and 40 girls), 80AD/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

Dupuy, Franca E; Barry, Robert J; Clarke, Adam R; McCarthy, Rory; Selikowitz, Mark



Music therapy modulates fronto-temporal activity in rest-EEG in depressed clients.  


Fronto-temporal areas process shared elements of speech and music. Improvisational psychodynamic music therapy (MT) utilizes verbal and musical reflection on emotions and images arising from clinical improvisation. Music listening is shifting frontal alpha asymmetries (FAA) in depression, and increases frontal midline theta (FMT). In a two-armed randomized controlled trial (RCT) with 79 depressed clients (with comorbid anxiety), we compared standard care (SC) versus MT added to SC at intake and after 3 months. We found that MT significantly reduced depression and anxiety symptoms. The purpose of this study is to test whether or not MT has an impact on anterior fronto-temporal resting state alpha and theta oscillations. Correlations between anterior EEG, Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hospital Anxiety and Depression Scale-Anxiety Subscale (HADS-A), power spectral analysis (topography, means, asymmetry) and normative EEG database comparisons were explored. After 3 month of MT, lasting changes in resting EEG were observed, i.e., significant absolute power increases at left fronto-temporal alpha, but most distinct for theta (also at left fronto-central and right temporoparietal leads). MT differed to SC at F7-F8 (z scored FAA, p < .03) and T3-T4 (theta, p < .005) asymmetry scores, pointing towards decreased relative left-sided brain activity after MT; pre/post increased FMT and decreased HADS-A scores (r = .42, p < .05) indicate reduced anxiety after MT. Verbal reflection and improvising on emotions in MT may induce neural reorganization in fronto-temporal areas. Alpha and theta changes in fronto-temporal and temporoparietal areas indicate MT action and treatment effects on cortical activity in depression, suggesting an impact of MT on anxiety reduction. PMID:22983820

Fachner, Jörg; Gold, Christian; Erkkilä, Jaakko



Interrater reliability of EEG-video monitoring  

PubMed Central

Objective: The diagnosis of psychogenic nonepileptic seizures (PNES) can be challenging. In the absence of a gold standard to verify the reliability of the diagnosis by EEG-video, we sought to assess the interrater reliability of the diagnosis using EEG-video recordings. Methods: Patient samples consisted of 22 unselected consecutive patients who underwent EEG-video monitoring and had at least an episode recorded. Other test results and histories were not provided because the goal was to assess the reliability of the EEG-video. Data were sent to 22 reviewers, who were board-certified neurologists and practicing epileptologists at epilepsy centers. Choices were 1) PNES, 2) epilepsy, and 3) nonepileptic but not psychogenic (“physiologic”) events. Interrater agreement was measured using a ? coefficient for each diagnostic category. We used generalized ? coefficients, which measure the overall level of between-method agreement beyond that which can be ascribed to chance. We also report category-specific ? values. Results: For the diagnosis of PNES, there was moderate agreement (? = 0.57, 95% confidence interval [CI] 0.39–0.76). For the diagnosis of epilepsy, there was substantial agreement (? = 0.69, 95% CI 0.51–0.86). For physiologic nonepileptic episodes, the agreement was low (? = 0.09, 95% CI 0.02–0.27). The overall ? statistic across all 3 diagnostic categories was moderate at 0.56 (95% CI 0.41–0.73). Conclusions: Interrater reliability for the diagnosis of psychogenic nonepileptic seizures by EEG-video monitoring was only moderate. Although this may be related to limitations of the study (diagnosis based on EEG-video alone, artificial nature of the forced choice paradigm, single episode), it highlights the difficulties and subjective components inherent to this diagnosis. GLOSSARY ABCN = American Board of Clinical Neurophysiology; ABPN = American Board of Psychiatry and Neurology; CI = confidence interval; IRR = interrater reliability; PNES = psychogenic nonepileptic seizures.

Benbadis, S R.; LaFrance, W C.; Papandonatos, G D.; Korabathina, K; Lin, K; Kraemer, H C.



Fractal Dimension in Epileptic EEG Signal Analysis  

NASA Astrophysics Data System (ADS)

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 greater speed and the criterion to choose the maximum and minimum values for time intervals. Comparisons with the other waveform fractal dimension algorithms are also demonstrated. In order to discriminate the Healthy and the Epileptic EEGs, an improved method of Multifractal Measure such as Generalized Fractal Dimensions (GFD) is also proposed. Finally we conclude that there are significant differences between the Healthy and Epileptic Signals in the designed method than the GFD through graphical and statistical tools. The improved multifractal measure is very efficient technique to analyze the EEG Signals and to compute the state of illness of the Epileptic patients.

Uthayakumar, R.


Preferred pre-stimulus EEG states affect cognitive event-related potentials.  


Current views of the genesis of the event-related potential (ERP) emphasize the contribution of ongoing oscillations - the ongoing electroencephalogram (EEG) is recognized as much more than "background noise" to be removed by response averaging to find the ERP. Early work from Ba?ar's group noted that repetitive stimuli led to selective phase re-ordering of activity in the delta and alpha bands, such that enhanced brain negativity occurred at the time of the regular stimulus. Other work related negativity in alpha activity at stimulus onset to improved reaction times and ERP enhancements. These findings led us to begin a program of brain dynamics studies exploring pre-stimulus EEG phase states, their preferential occurrence in paradigms with regularly presented stimuli, and their relation to ERP outcomes. In particular, with very narrow EEG bands, we have repeatedly found that certain phase states preferentially occur at stimulus onset, implying ongoing phase re-ordering driven by stimulus occurrence. Effects are weakened with slightly varying inter-stimulus intervals, but still occur reliably. Further, these preferential phase states are functionally effective in relation to the ERP correlates of efficient stimulus processing. Preferential phase occurrence and their effects were originally reported in auditory oddball tasks, using narrow EEG bands derived by digital filtering. A recent study is presented illustrating generalization of the phenomenon in the auditory Go/NoGo task, using narrow bands derived by FFT techniques. Our current work is extending this research in normal children (to provide a comparative context for research in children with AD/HD), and well-functioning elderly (to provide a context for future work in relation to Alzheimer's disease). PMID:24053031

Barry, Robert J



Subclinical exposure to low-dose endotoxin impairs EEG maturation in preterm fetal sheep.  


Exposure to chorioamnionitis is strongly associated with neurodevelopmental disability after premature birth; however, it remains unclear whether subclinical infection affects functional EEG maturation. Chronically instrumented 103-104-day-old (0.7 gestational age: term 147 days) fetal sheep in utero were randomized to receive either gram-negative LPS by continuous low-dose infusion (100 ng iv over 24 h, followed by 250 ng/24 h for 4 days; n = 6) or the same volume of normal saline (n = 9). Arterial plasma cortisol, ACTH, and IL-6 were measured. The delta (0-3.9 Hz), theta (4-7.9 Hz), alpha (8-12.9 Hz), and beta (13-22 Hz) components of the EEG were determined by power spectral analysis. Brains were taken after 10 days for histopathology. There were no changes in blood gases, cardiovascular variables, or EEG power during LPS infusion, but a transient rise in plasma cortisol and IL-6 (P < 0.05). LPS infusion was associated with loss of the maturational increase to higher frequency activity, with reduced alpha and beta power, and greater delta power than saline controls from 6 to 10 days (P < 0.05). Histologically, LPS was associated with increased numbers of microglia and TNF-?-positive cells in the periventricular white matter and frontoparietal cortex, increased caspase-3-positive cells in white matter, but no loss of CNPase-positive oligodendrocytes, Nurr-1 subplate cells, or gyral complexity. These data suggest that low-dose endotoxin exposure can impair EEG maturation in preterm fetal sheep in association with neural inflammation but without hemodynamic disturbances or cortical injury. PMID:22696578

Keogh, Michael J; Bennet, Laura; Drury, Paul P; Booth, Lindsea C; Mathai, Sam; Naylor, Andrew S; Fraser, Mhoyra; Gunn, Alistair J



Left-right information flow in the brain during EEG arousals.  


In disorders such as sleep apnea, sleep is fragmented with frequent EEG-arousal (EEGA) as determined via changes in the sleep-electroencephalogram. EEGA is a poorly understood, complicated phenomenon which is critically important in studying the mysteries of sleep. In this paper we study the information flow between the left and right hemispheres of the brain during the EEGA as manifested through inter-hemispheric asynchrony (IHA) of the surface EEG. EEG data (using electrodes A1/C4 and A2/C3 of international 10-20 system) was collected from 5 subjects undergoing routine polysomnography (PSG). Spectral correlation coefficient (R) was computed between EEG data from two hemispheres for delta-delta(0.5-4 Hz), theta-theta(4.1-8 Hz), alpha-alpha(8.1-12 Hz) & beta-beta(12.1-25 Hz) frequency bands, during EEGA events. EEGA were graded in 3 levels as (i) micro arousals (3-6 s), (ii) short arousals (6.1-10 s), & (iii) long arousals (10.1-15 s). Our results revealed that in beta band, IHA increases above the baseline after the onset of EEGA and returns to the baseline after the conclusion of event. Results indicated that the duration of EEGA events has a direct influence on the onset of IHA. The latency (L) between the onset of arousals and IHA were found to be L=2 +/- 0.5 s (for micro arousals), 4 +/- 2.2 s (short arousals) and 6.5 +/- 3.6 s (long arousals). PMID:17947181

Swarnkar, V; Abeyratne, Udantha R; Karunajeewa, A S



Atypical alpha asymmetry in adults with ADHD*  

PubMed Central

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 asymmetry has been associated with ADHD-like traits such as reduced reward responsiveness, a lack of inhibition toward aversive experience, and increased approach behaviors, and previous work has indicated increased rightward alpha asymmetry in children with ADHD. The current study explores whether increased rightward alpha asymmetry is also evident in adults with ADHD. Method We assessed low (8– 10 Hz) and high (10– 12 Hz) alpha asymmetry in adults with ADHD (n = 29) versus controls (n = 62) during baseline and cognitive activation conditions for nine homologous electrode pairs along the anterior–posterior axis. Result Seven results emerged (p < .05) showing increased rightward alpha asymmetry in adults with ADHD. This occurred in three specific electrode pairs across two testing conditions, and five of six results occurred in the lower alpha band. Finally, post hoc analysis indicated that increased rightward alpha asymmetry was generally associated with greater numbers of ADHD symptoms—with a possible parietal association for inattentive and a fronto-temporal association for hyperactivity symptoms. Conclusions Increased rightward alpha asymmetry previously observed in children with ADHD appears to be a developmentally persistent feature of ADHD.

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



Tomographic Distribution of Resting Alpha Rhythm Sources Revealed by Independent Component Analysis  

Microsoft Academic Search

Introduction \\u000d\\u000aThe 8-12 Hz EEG alpha rhythm is thought to be characteristic of resting cortex, and its scalp distribution may indicate regional differences in brain state. In resting fMRI studies, many groups have observed significant fluctuations in the BOLD signal whose associations with cognitive states are uncertain. In a previous report (1) using simultaneous EEG and fMRI (SITE, or Simultaneous

R. I. Goldman; M. S. Cohen


Dense Array EEG Source Estimation in Neocortical Epilepsy  

PubMed Central

Rationale: Dense array EEG (dEEG) evenly covers the whole head surface with over 100 channels contributing to more accurate electrical source imaging due to the higher spatial and temporal resolution. Several studies have shown the clinical utility of dEEG in presurgical clinical evaluation of epilepsy. However validation studies measuring the accuracy of dEEG source imaging are still needed. This can be achieved through simultaneously recording both scalp dEEG with intracranial electrodes (icEEG), which is considered as the true measure of cortical activity at the source. The purpose of this study is to evaluate the accuracy of 256-channel dEEG electrical source estimation for interictal spikes. Methods: Four patients with medically refractory neocortical epilepsy, all surgical candidates, underwent subdural electrode implantation to determine ictal onset and define functional areas. One patient showed a lesion on the magnetic resonance imaging in the right parietal lobe. The patient underwent simultaneous recording of interictal spikes by both scalp 256-channelsvdEEG and icEEG. The dEEG was used to non-invasively estimate the source of the interictal spikes detected by the 256-channel dEEG array, which was then compared to the activity measured directly at the source by the icEEG. Results: From the four patients, a total of 287 interictal spikes were measured with the icEEG. One hundred fifty-five of the 287 spikes (54%) were visually detected by the dEEG upon examination of the 256 channel head surface array. The spike amplitudes detected by the 256-channel dEEG correlated with icEEG spike amplitudes (p?EEG were localized to the same lobe correctly. Conclusion: Our study demonstrates that 256-channel dEEG can reliably detect interictal spikes and localize them with reasonable accuracy. Two hundred fifty-six-channel dEEG may be clinically useful in the presurgical workup for epilepsy and also reduce the need for invasive EEG evaluation.

Yamazaki, Madoka; Tucker, Don M.; Terrill, Marie; Fujimoto, Ayataka; Yamamoto, Takamichi



EEG correlates of haptic feedback in a visuomotor tracking task.  


This study investigates the temporal brain dynamics associated with haptic feedback in a visuomotor tracking task. Haptic feedback with deviation-related forces was used throughout tracking experiments in which subjects' behavioral responses and electroencephalogram (EEG) data were simultaneously measured. Independent component analysis was employed to decompose the acquired EEG signals into temporally independent time courses arising from distinct brain sources. Clustering analysis was used to extract independent components that were comparable across participants. The resultant independent brain processes were further analyzed via time-frequency analysis (event-related spectral perturbation) and event-related coherence (ERCOH) to contrast brain activity during tracking experiments with or without haptic feedback. Across subjects, in epochs with haptic feedback, components with equivalent dipoles in or near the right motor region exhibited greater alpha band power suppression. Components with equivalent dipoles in or near the left frontal, central, left motor, right motor, and parietal regions exhibited greater beta-band power suppression, while components with equivalent dipoles in or near the left frontal, left motor, and right motor regions showed greater gamma-band power suppression relative to non-haptic conditions. In contrast, the right occipital component cluster exhibited less beta-band power suppression in epochs with haptic feedback compared to non-haptic conditions. The results of ERCOH analysis of the six component clusters showed that there were significant increases in coherence between different brain networks in response to haptic feedback relative to the coherence observed when haptic feedback was not present. The results of this study provide novel insight into the effects of haptic feedback on the brain and may aid the development of new tools to facilitate the learning of motor skills. PMID:22348883

Lin, Chun-Ling; Shaw, Fu-Zen; Young, Kuu-Young; Lin, Chin-Teng; Jung, Tzyy-Ping



The acute soporific action of daytime melatonin administration: effects on the EEG during wakefulness and subjective alertness.  


Melatonin has been reported to have soporific effects; following daytime administration, it induces sleepiness and reduces sleep onset latency. However, subjective sleepiness is masked by a variety of stimuli and behaviors; thus, it is important to be able to delineate objective psychophysiological sequelae of melatonin administration. Alertness decrements during wakefulness are correlated with augmented theta/alpha power in the waking electroencephalogram (EEG). This has been validated in a constant routine protocol. In a variety of experiments with melatonin administration (5 mg), the authors have shown that the EEG changes can be measured immediately, before any subjective soporific effects are recognized. These increases in theta/alpha power occur when melatonin is administered during the day (1300 or 1800 h) but are less visible when near the endogenous melatonin rise in the evening (2040 h). Importantly, both subjective and objective measures of sleepiness are suppressed when subjects change posture from supine to standing. PMID:9406039

Cajochen, C; Kräuchi, K; Wirz-Justice, A



Functional connectivity of frontal cortex in healthy and ADHD children reflected in EEG coherence.  

PubMed Central

Abnormal functional brain connectivity is a candidate factor in developmental brain disorders associated with cognitive dysfunction. We analyzed a substantial (ten minute per subject) record of dense array EEG with spectral power and coherence methods in ADHD (n = 42) and Control (n = 21) 10–13 year old children. We found topographically distinct narrow band coherence differences between subject groups: ADHD subjects showed elevated coherence in the lower alpha (8 Hz) band and reduced coherence in the upper alpha (10–11 Hz) band. The 8 Hz ADHD elevation, and a 2–6 Hz Control group coherence elevation, were independent of stimulus presentation. In response to visual stimulation, the ADHD group exhibited reduced evoked potential power and elevated frontal coherence. Only the upper alpha band control group coherence elevation discriminated according to ADHD group medication status. The findings suggest a static state of deficient connectivity in ADHD, and a stimulus induced state of over-connectivity within and between frontal hemispheres.

Murias, Michael; Swanson, James M.; Srinivasan, Ramesh



EEG correlates of enhanced spatial performance following exposure to music.  


Previous research has shown that exposure to classical music can influence performance on a spatial task. The present study investigated EEG correlates of this enhanced performance effect, 4 female and 4 male undergraduates completed two equivalent spatial tests, one following a control procedure and one following the presentation of Mozart's Sonata for Two Pianos in D Major. EEG was recorded during a baseline and two task-performance periods. Test performance and EEG recordings were analyzed, and correlations were generated between task performance and EEG variables (average spectral power and peak frequency within 5 frequency ranges). Performance improved significantly following the presentation of the music. EEG analysis indicated 6 reliable correlations out of 40 calculated between differential EEG variables and changes in performance. Ten reliable correlations out of 120 were also found between changes in performance and nondifferential EEG variables across baseline, control, and experimental conditions. PMID:8724912

Rideout, B E; Laubach, C M



EEG-based communication: prospects and problems  

Microsoft Academic Search

Current rehabilitation engineering combines new prosthetic methods with recent developments in personal computers to provide alternative communication and control channels to individuals with motor impairments. Despite these advances, all commercially available systems still require some measure of voluntary motor control. Thus, these systems are not useful for individuals who are totally paralyzed. Electroencephalographic (EEG) activity may provide the basis for

Theresa M. Vaughan; Jonathan R. Wolpaw; Emanuel Donchin



The EEG Signal Process Based on EEMD  

Microsoft Academic Search

Hilbert Huang Transform (HHT), which is based on EMD (Empirical Mode Decomposition) and Hilbert transform method, is a new signal analysis method. It suits for analyzing the non-linear and non-stationary signals, such as EEG signal particularly. The traditional EMD method has the Mode Mixing problem. Therefore a new method basing on Ensemble Empirical Mode Decomposition (EEMD) for processing the signal

Zhu Xiao-jun; Lv Shi-qin; Liu-juan Fan; Xue-li Yu



Period Analysis of Space Flight EEG.  

National Technical Information Service (NTIS)

The research reported illustrates how different combinations of three descriptors of the EEG may be used to delineate space flight sleep patterns. The three descriptors examined are the zero crossings, points of zero slope, and points of zero change in sl...

A. J. Welch



Multitask learning for EEG-based biometrics  

Microsoft Academic Search

Biometrics based on electroencephalogram (EEG) signals is an emerging research topic. Several recent results have shown its feasibility and potential for per- sonal identification. However, they all use a single task (e.g., signals recorded during imagination of repetitive left hand movements or during resting with eyes open) for classifier design and subsequent identification. In contrast with this, in this paper

Shiliang Sun



[Information method of EEG analysis in anesthesiology].  


An information concept of nociceptive impulses is proposed. The device for quantitative analysis of information coming to CNS has been constructed and approved. It is demonstrated that monitoring of informative loading of EEG may be used for evaluation of anesthesia adequacy. Level of this index from 40 to 50% corresponds to effective protection. PMID:12698660

Likhvantsev, V V; Subbotin, V V; Petrov, O V; Sitnikov, A V; Kazanikova, A N; Zhuravel', S V



Imaging neural activity using MEG and EEG  

Microsoft Academic Search

The authors have developed a Bayesian framework for image estimation from combined MEG\\/EEG data. Their results indicate that performance of their imaging approach is superior to that of weighted minimum norm when the image is sparse and focal. Note however that if the image is not sparse, the authors' method would perform poorly since their prior is specifically designed to

J. W. Phillips; R. M. Leahy; J. C. Mosher; B. Timsari



Music Shifts Frontal EEG in Depressed Adolescents.  

ERIC Educational Resources Information Center

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…

Field, Tiffany; Martinez, Alex; Nawrocki, Thomas; Pickens, Jeffrey; Fox, Nathan A.; Schanberg, Saul



Nonlinear analysis of EEG for epileptic seizures.  

National Technical Information Service (NTIS)

We apply chaotic time series analysis (CTSA) to human electroencephalogram (EEG) data. Three epoches were examined: epileptic seizure, non-seizure, and transition from non-seizure to seizure. The CTSA tools were applied to four forms of these data: raw EE...

L. M. Hively N. E. Clapp C. S. Daw W. F. Lawkins M. L. Eisenstadt



EEG dipole modeling in complex partial epilepsy  

Microsoft Academic Search

Summary Visual inspection and qualitative impressions of clinical EEG abnormalities are being replaced by quantitative characterization of scalp voltage fields and dipole modeling of underlying cerebral sources. Three approaches have been used in the analysis of focal spikes of complex partial epilepsy. 1) Instantaneous, single dipole, inverse solutions for the voltage topography of the spike peak have revealed two distinct

John S. Ebersole



Statistical maps for EEG dipolar source localization  

Microsoft Academic Search

We present a method that estimates three-dimensional statistical maps for electroencephalogram (EEG) source localization. The maps assess the likelihood that a point in the brain contains a dipolar source, under the hypothesis of one, two or three activated sources. This is achieved by examining all combinations of one to three dipoles on a coarse grid and attributing to each combination

Christian-G. Bénar; Roger N. Gunn; Christophe Grova; Benoît Champagne; Jean Gotman



Facilitation of performance on an arithmetic task as a result of the application of a biofeedback procedure to suppress alpha wave activity  

Microsoft Academic Search

An electroencephalographic (EEG) biofeedback procedure was used in a pilot study to decrease the percent of time in alpha wave activity with five mentally retarded adults while engaged in an arithmetic test. Analysis of intrasubject and intersubject data revealed an overall significant decrease in the number of alpha events and percent of time in alpha wave activity as compared to

Gary M. Jackson; David A. Eberly



Association Analysis of Exonic Variants of the GABA B Receptor Gene and Alpha Electroencephalogram Voltage in Normal Subjects and Alcohol-Dependent Patients  

Microsoft Academic Search

Based on pharmacologic evidence, it has been suggested that GABAB receptors may play a crucial role in the generation of alpha-electroencephalogram (EEG) oscillations. We tested whether three exonic variants of the gene encoding the human GABAB receptor (GABABR1) modify scalp-recorded alpha-EEG voltage. One hundred twenty-eight patients suffering from alcoholism and 114 normal subjects were investigated. Alcohol-dependent patients were included because

Georg Winterer; Richard Mahlberg; Michael N. Smolka; Jerzy Samochowiec; Mario Ziller; Hans-Peter Rommelspacher; Werner M. Herrmann; Lutz G. Schmidt; Thomas Sander



Neonatal screening for alpha-1-antitrypsin deficiency  

Microsoft Academic Search

The results of a neonatal screening programme for alpha-1-antitrypsin deficiency are presented. Cord blood samples with an alpha-1-antitrypsin concentration below 1.628 mg\\/ml, as measured by an enzyme-linked immunosorbent assay method, were phenotyped by isoelectric focusing in polyacrylamide gels. Abnormal phenotypes were found in 51% of this group as compared with 11.3% in a control group (P«0.0001). Twenty subjects detected by

J. Kimpen; E. Bosmans; J. Raus



EEG microstates of wakefulness and NREM sleep.  


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 classes in all NREM sleep stages might speak in favor of an in principle maintained large scale spatial brain organization from wakeful rest to NREM sleep. In N1 and N3 sleep, despite spectral EEG differences, the microstate maps and characteristics were surprisingly close to wakefulness. This supports the notion that EEG microstates might reflect a large scale resting state network architecture similar to preserved fMRI resting state connectivity. We speculate that the incisive functional alterations which can be observed during the transition to deep sleep might be driven by changes in the level and timing of activity within this architecture. PMID:22658975

Brodbeck, Verena; Kuhn, Alena; von Wegner, Frederic; Morzelewski, Astrid; Tagliazucchi, Enzo; Borisov, Sergey; Michel, Christoph M; Laufs, Helmut



Roles of Adrenergic ?1 and Dopamine D1 and D2 Receptors in the Mediation of the Desynchronization Effects of Modafinil in a Mouse EEG Synchronization Model  

PubMed Central

Background Synchronized electroencephalogram (EEG) activity is observed in pathological stages of cognitive impairment and epilepsy. Modafinil, known to increase the release of catecholamines, is a potent wake-promoting agent, and has shown some abilities to desynchronize EEG,but its receptor mechanisms by which modafinil induces desynchoronization remain to be elucidated. Here we used a pharmacological EEG synchronization model to investigate the involvement of adrenergic ?1 receptors (R, ?1R) and dopamine (DA) D1 and D2 receptors (D1Rs and D2Rs) on modafinil-induced desynchronization in mice. Methodology/Principal Findings Mice were treated with cholinergic receptor antagonist scopolamine and monoamine depletor reserpine to produce experimental EEG synchronization characterized by continuous large-amplitude synchronized activity, with prominent increased delta and decreased theta, alpha, and beta power density. The results showed that modafinil produced an EEG desynchronization in the model. This was characterized by a general decrease in amplitude of all the frequency bands between 0 and 20 Hz, a prominent reduction in delta power density, and an increase in theta power density. Adrenergic ?1R antagonist terazosin (1 mg/kg, i.p.) completely antagonized the EEG desynchronization effects of modafinil at 90 mg/kg. However, DA D1R and D2R blockers partially attenuated the effects of modafinil. The modafinil-induced decrease in the amplitudes of the delta, theta, alpha, and beta waves and in delta power density were completely abolished by pretreatment with a combination of the D1R antagonist SCH 23390 (30 µg/kg) and the D2R antagonist raclopride (2 mg/kg, i.p.). Conclusions/Significance These results suggest that modafinil-mediated desynchronization may be attributed to the activation of adrenergic ?1R, and dopaminergic D1R and D2R in a model of EEG synchronization.

Chen, Chang-Rui; Yang, Su-Rong; Liu, Yuan-Yuan; Qu, Wei-Min; Urade, Yoshihiro; Huang, Zhi-Li



The Role of Epilepsy and Epileptiform EEGs in Autism Spectrum Disorders  

PubMed Central

Autism is a neurodevelopmental disorder of unknown etiology characterized by social and communication deficits and the presence of restricted interests/repetitive behaviors. Higher rates of epilepsy have long been reported, but prevalence estimates vary from as little as 5% to as much as 46%. This variation is probably the result of sample characteristics that increase epilepsy risk such as sample ascertainment, lower IQ, the inclusion of patients with non-idiopathic autism, age, and gender. However, critical review of the literature reveals that the rate in idiopathic cases with normal IQ is still significantly above the population risk suggesting that autism itself is associated with an increased risk of epilepsy. Recently there has been interest in the occurrence of epileptiform electroencephalograms (EEGs) even in the absence of epilepsy. Rates as high as 60% have been reported and some investigators propose that these abnormalities may play a causal role in the autism phenotype. While this phenomenon is still not well understood and risk factors have yet to be determined, the treatment implications are increasingly important. We review the recent literature to elucidate possible risk factors for both epilepsy and epileptiform EEGs. We then review existing data and discuss controversies surrounding treatment of EEG abnormalities.

Spence, Sarah J; Schneider, Mark T



Functional coupling of sensorimotor and associative areas during a catching ball task: a qEEG coherence study  

PubMed Central

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.



Pharmacological modulation of cholinergic brain activity and its reflection in special EEG frequency ranges from various brain areas in the freely moving rat (Tele-Stereo-EEG).  


Due to the electrochemical nature of the communication structure of the brain an intimate relationship between neurotransmitter activity on one side and field potentials (EEG) on the other side can be suspected. In order to learn more about this relationship pharmacological manipulation of the cholinergic transmitter system by means of agonistic and antagonistic receptor active drugs was used. Continuous recording of electrical activity from four selected brain areas (frontal cortex, hippocampus, striatum and reticular formation) in freely moving day-night converted Fisher rats was used (Tele-Stereo-EEG). Frequency analysis of telemetrically transmitted data and special definitions of frequency ranges were used to analyse the data from 45 min pre-drug and 180 min postdrug periods. Pharmacological modulation of brain activity by the selective nicotinic agonist metanicotine as well as the alpha 7 selective nicotinic antagonist methyllycaconitine revealed major changes in delta (1-4.5 Hz) and alpha2 (9-12.5 Hz) frequencies. In general blockade of the cholinergic system resulted in electrical power increases and activation in decreases. Unspecific modulation of cholinergic activity by using the cholinesterase inhibitors physostigmine, tacrine and galantamine led to alpha1 frequency (7-9.5 Hz) changes in addition to the delta and alpha2 changes. These three drugs produced a nearly identical pattern of frequency changes. Theta (4.75-6.75 Hz) and beta1 frequencies (12.75-18.5 Hz) changed to a lesser degree. A peculiar finding arose with respect to the effects of the antagonistic drugs scopolamine and biperiden since biperiden-besides the massive increase of delta and alpha1 power in common-induced a general decrease of alpha2 frequencies within all brain areas opposite to the effect of scopolamine. This special property of biperiden gives a plausible explanation for its efficacy in Parkinsonian patients since decreases of alpha2 waves in this model indicate enhancement of dopaminergic transmission [Dimpfel, W., Spüler, M., Koch, R., Schatton, W., 1987. Radioelectroencephalographic comparison of memantine with receptor-specific drugs acting on dopaminergic transmission in freely moving rats. Neuropsychobiology 18, 212-218]. Except for the effects of methyllycaconitine (p<10%) all results were statistically significant at least at the p<5% level. The results are best explained by assuming that electrical delta activity reflects cholinergic transmitter control followed by and closely linked to changes in dopaminergic transmission as indicated by additional concomitant changes in alpha2 electrical power. PMID:16009538

Dimpfel, Wilfried



The EEG Denoising Research Based on Wavelet and Hilbert Transform Method  

Microsoft Academic Search

To remove the noises of EEG effectively, this paper makes the EEG De-noising research about Wavelet and Hilbert Transform. In HHT De-noising process, first, according to EEG own frequency characteristics, the EEG signals are made eight scales decomposition by using EMD algorithm, and obtain eight IMF component signals. Second, reconstruct the IMF component signals after filtering. Finally, get the EEG

Fei-long Yuan; Zhi-zeng Luo



Removal of Scalp Reference Signal and Line Noise for Intracranial EEGs  

Microsoft Academic Search

Cephalic references are widely used to record Electroencephalography (EEG). The effect of an active common reference on the recorded EEG is one of the oldest technical problems in the study of EEG. Moreover, in many cases EEG channel recordings are contaminated to different degrees with line noise that can pose a significant problem for EEG interpretation and analysis. Thus, identification

Sanqing Hu; Matt Stead; Gregory A. Worrell



Effect of bright light on EEG activities and subjective sleepiness to mental task during nocturnal sleep deprivation.  


The purpose of this study was to investigate the effect of the exposure to bright light on EEG activity and subjective sleepiness at rest and at the mental task during nocturnal sleep deprivation. Eight male subjects lay awake in semi-supine in a reclining seat from 21:00 to 04:30 under the bright (BL; >2500 lux) or the dim (DL; <150 lux) light conditions. During the sleep deprivation, the mental task (Stroop color-word conflict test: CWT) was performed each 15 min in one hour. EEG, subjective sleepiness, rectal and mean skin temperatures and urinary melatonin concentrations were measured. The subjective sleepiness increased with time of sleep deprivation during both rest and CWT under the DL condition. The exposure to bright light delayed for 2 hours the increase in subjective sleepiness at rest and suppressed the increase in that during CWT. The bright light exposure also delayed the increase in the theta and alpha wave activities in EEG at rest. In contrast, the effect of the bright light exposure on the theta and alpha wave activities disappeared by CWT. Additionally, under the BL condition, the entire theta activity during CWT throughout nocturnal sleep deprivation increased significantly from that in a rest condition. Our results suggest that the exposure to bright light throughout nocturnal sleep deprivation influences the subjective sleepiness during the mental task and the EEG activity, as well as the subjective sleepiness at rest. However, the effect of the bright light exposure on the EEG activity at the mental task diminishes throughout nocturnal sleep deprivation. PMID:14646259

Yokoi, Mari; Aoki, Ken; Shimomura, Yoshihiro; Iwanaga, Koichi; Katsuura, Tetsuo; Shiomura, Yoshihiro



EEG spectro-temporal modulation energy: a new feature for automated diagnosis of Alzheimer's disease.  


There is recent indication that Alzheimer's disease (AD) can be characterized by atypical modulation of electrophysiological brain activity caused by fibrillar amyloid deposition in specific regions of the brain, such as those related to cognition and memory. In this paper, we propose to objectively characterize EEG sub-band modulation in an attempt to develop an automated noninvasive AD diagnostics tool. First, multi-channel full-band EEG signals are decomposed into five well-known frequency sub-bands: delta, theta, alpha, beta, and gamma. The temporal amplitude envelope of each sub-band is then computed via a Hilbert transformation. The proposed 'spectro-temporal modulation energy' feature measures the rate with which each sub-band is modulated. Modulation energy features are computed for 19 referential EEG signals and seven bipolar signals. Salient features are then selected and used to train four different classifiers, namely, support vector machines, logistic regression, classification and regression trees, and neural networks. Experiments with a database of 34 participants, 22 of which have been clinically diagnosed with probable-AD, show a neural network classifier achieving over 91% accuracy, thus significantly outperforming a classifier trained with conventional spectral-based features. PMID:22255174

Trambaiolli, Lucas R; Falk, Tiago H; Fraga, Francisco J; Anghinah, Renato; Lorena, Ana C



Disturbed resting state EEG synchronization in bipolar disorder: A graph-theoretic analysis?  

PubMed Central

Disruption of functional connectivity may be a key feature of bipolar disorder (BD) which reflects disturbances of synchronization and oscillations within brain networks. We investigated whether the resting electroencephalogram (EEG) in patients with BD showed altered synchronization or network properties. Resting-state EEG was recorded in 57 BD type-I patients and 87 healthy control subjects. Functional connectivity between pairs of EEG channels was measured using synchronization likelihood (SL) for 5 frequency bands (?, ?, ?, ?, and ?). Graph-theoretic analysis was applied to SL over the electrode array to assess network properties. BD patients showed a decrease of mean synchronization in the alpha band, and the decreases were greatest in fronto-central and centro-parietal connections. In addition, the clustering coefficient and global efficiency were decreased in BD patients, whereas the characteristic path length increased. We also found that the normalized characteristic path length and small-worldness were significantly correlated with depression scores in BD patients. These results suggest that BD patients show impaired neural synchronization at rest and a disruption of resting-state functional connectivity.

Kim, Dae-Jin; Bolbecker, Amanda R.; Howell, Josselyn; Rass, Olga; Sporns, Olaf; Hetrick, William P.; Breier, Alan; O'Donnell, Brian F.



Correlated components of ongoing EEG point to emotionally laden attention - a possible marker of engagement?  


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

Dmochowski, Jacek P; Sajda, Paul; Dias, Joao; Parra, Lucas C



Validation of Regression-Based Myogenic Correction Techniques for Scalp and Source-Localized EEG  

PubMed Central

EEG and EEG source-estimation are susceptible to electromyographic artifacts (EMG) generated by the cranial muscles. EMG can mask genuine effects or masquerade as a legitimate effect - even in low frequencies, such as alpha (8–13Hz). Although regression-based correction has been used previously, only cursory attempts at validation exist and the utility for source-localized data is unknown. To address this, EEG was recorded from 17 participants while neurogenic and myogenic activity were factorially varied. We assessed the sensitivity and specificity of four regression-based techniques: between-subjects, between-subjects using difference-scores, within-subjects condition-wise, and within-subject epoch-wise on the scalp and in data modeled using the LORETA algorithm. Although within-subject epoch-wise showed superior performance on the scalp, no technique succeeded in the source-space. Aside from validating the novel epoch-wise methods on the scalp, we highlight methods requiring further development.

McMenamin, Brenton W.; Shackman, Alexander J.; Maxwell, Jeffrey S.; Greischar, Lawrence L.; Davidson, Richard J.



The EEG correlates of the TMS-induced EMG silent period in humans.  


Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson's disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments. PMID:23800790

Farzan, Faranak; Barr, Mera S; Hoppenbrouwers, Sylco S; Fitzgerald, Paul B; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J



Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.  


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

Subhani, Ahmad Rauf; Likun, Xia; Saeed Malik, Aamir



Genetically altered mice: phenotypes, no phenotypes, and Faux phenotypes  

Microsoft Academic Search

Phenotype’ means different things, but whatever the measure, phenotype can be profoundly influenced by genetic, environmental and infectious variables. The laboratory mouse is a complex multisystemic organism which, despite its genetically inbred nature, as highly variable pathophysiologic characteristics. Mouse strains have background characteristics that can influence genomics research. In addition to the mouse itself, different approaches toward creating mutant mice

Stephen W. Barthold



Oligoclonal repertoire of the CD8 alpha alpha and the CD8 alpha beta TCR-alpha/beta murine intestinal intraepithelial T lymphocytes: evidence for the random emergence of T cells  

PubMed Central

The epithelium of the small intestine in normal euthymic mice contains a large number of intraepithelial lymphocytes (IEL), some of which bear a T cell receptor alpha/beta (TCR-alpha/beta). About half of these TCR- alpha/beta IEL display the CD8 alpha alpha phenotype and the remaining have the CD8 alpha beta or the CD4 phenotypes. To examine whether TCR- alpha/beta IEL have a TCR-beta chain repertoire as diverse as that of TCR-alpha/beta lymph node lymphocytes (LNL), we used a recently described PCR technique that allows a global analysis of the TCR-beta chain repertoire. Within any given mouse, the repertoires expressed in both CD8 alpha alpha and CD8 alpha beta TCR-alpha/beta IEL populations are oligoclonal and nonoverlapping between the two subsets. The clones are largely conserved through the length of the small intestine of the same individual. However, genetically identical individuals raised under indistinguishable environmental conditions display distinct oligoclonal repertoires. Those findings indicate that few cells of CD8 alpha alpha or of the CD8 alpha beta phenotype are responsible for the repopulation of the intestinal epithelium.



Rapid EEG desynchronization and EMG activation induced by intravenous cocaine in freely moving rats: a peripheral, nondopamine neural triggering  

PubMed Central

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 (?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 elements and involving rapid neural transmission. By providing a rapid neural signal and triggering transient neural activation, such an action might play a crucial role in the sensory effects of COC, thus contributing to the learning and development of drug-taking behavior.

Smirnov, Michael S.



Repeating video/EEG monitoring: why and with what results?  


Prolonged video/EEG monitoring is the main activity of referral tertiary epilepsy centers. Occasionally, monitoring is repeated in the same patient, but this subgroup has not been specifically studied. The purpose of this study was to analyze repeated video/EEG monitoring. We reviewed all sessions of inpatient video/EEG monitoring performed over 3 years (2005-2008), and selected the ones that were repeated in the same patient. A total of 1063 video/EEG monitoring sessions were performed. Of these, 43 (4.0%) were "redos." The most common indication for repeat video/EEG monitoring was evidence of focal epilepsy with no recorded seizures, followed by normal interictal EEG with no recorded episodes. The second session answered the question in 35 (81%) cases, whereas the question remained unanswered in 8 (19%). The repeated session was useful in 35 (81%) cases. PMID:20634145

Muniz, Juan; Benbadis, Selim R



A Study of Evoked Potentials From Ear-EEG.  


A method for brain monitoring based on measuring the electroencephalogram (EEG) from electrodes placed in-the-ear (ear-EEG) was recently proposed. The objective of this study is to further characterize the ear-EEG and perform a rigorous comparison against conventional on-scalp EEG. This is achieved for both auditory and visual evoked responses, over steady-state and transient paradigms, and across a population of subjects. The respective steady-state responses are evaluated in terms of signal-to-noise ratio and statistical significance, while the qualitative analysis of the transient responses is performed by considering grand averaged event-related potential (ERP) waveforms. The outcomes of this study demonstrate conclusively that the ear-EEG signals, in terms of the signal-to-noise ratio, are on par with conventional EEG recorded from electrodes placed over the temporal region. PMID:23722447

Kidmose, Preben; Looney, David; Ungstrup, Michael; Rank, Mike Lind; Mandic, Danilo P



A Time-Variant Processing Approach for the Analysis of Alpha and Gamma MEG Oscillations During Flicker Stimulus Generated Entrainment  

Microsoft Academic Search

Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteris- tics of stimulation-sensitive neuronal oscillators by means of the MEG\\/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the

Matthias Wacker; Miroslav Galicki; Peter Putsche; Thomas Milde; Karin Schwab; Jens Haueisen; Carolin Ligges; Herbert Witte



Integrating eye-tracking and wireless Electroencephalogram (EEG) in consumer neuroscience.  


Consumer neuroscience addresses marketing relevant problems through the integration and application of neuroscientific theories, concepts, findings and methods to the research discipline of consumer behavior. The key contribution of this paper is to complement the advancement of traditional consumer research through the investigation of the patterns of interdependency between the Electroencephalogram (EEG) signals from the different brain regions while participants undertook a choice task designed to elicit preferences for a marketing product (crackers). Specifically, the task required participants to choose their preferred crackers described by shape (square, triangle, round), flavor (wheat, dark rye, plain) and topping (salt, poppy, no topping).We analyze the Electroencephalogram (EEG) signals collected from the different brain regions using the commercially available 14 channel Emotiv EPOC wireless EEG headset and relate the EEG data to the specific choice options with a Tobii X60 eye tracker. Fifteen participants were recruited for this experiment and were shown 57 choice sets; each choice set described three choice options. The patterns of cortical activity were obtained in the five principal frequency bands, Delta (0 - 4 Hz), Theta (3 - 7 Hz), Alpha (8 - 12 Hz), Beta (13 - 30 Hz), and Gamma (30 - 40 Hz). Our results indicate significant phase synchronization between the left and right frontal and occipital regions indicating interhemispheric communications during the choice task. Our experimental results also show that participants spent more time looking at the non-preferred items in each choice set at the beginning of the experiment (exploration mode), while reducing that time progressively to indicate significant amount of cognitive processing assigned to preferred items (exploitation mode). PMID:24111337

Khushaba, Rami N; Wise, Chelsea; Kodagoda, Sarath; Louviere, Jordan



Ambulatory EEG telemetry: how good is it?  


When someone asks the question, how good is ambulatory EEG telemetry, there is no correct answer. There are many manufacturers of ambulatory EEG technology. Each device has its own strengths and weaknesses. What one is really interested in when one asks such a question needs to be defined in terms of expectations and technical capabilities for the piece of equipment under discussion. Systems exist or can be easily modified to be as sophisticated as the best of the inpatient units. However, is that level of sophistication needed for the ambulatory based recordings? Again, the answer to that is dependent on the ordering physician's expectations. Below is a discussion of the different clinical expectations that are frequently encountered and the needed requirements for an ambulatory system to properly address them. PMID:16885704

Schomer, Donald L



EEG phase synchronization during hypnosis induction.  


Hypnosis is a mental state or set of attitudes usually induced by a procedure known as hypnotic induction. In order to provide the basic physiological conditions for potentially successful hypnosis treatment of medical and psychological problems, the determination of a subject's hypnotizability level is important. Currently, the hypnotizability level is determined using different standard subjective tests. To avoid the different drawbacks of these subjective clinical tests, a practical objective method based on the correlation between electroencephalograph (EEG) phase synchronization and hypnosis susceptibility levels is presented in this study. This method can be used by clinicians instead of the traditional subjective methods to classify hypnotizability level. Thirty-two subjects with different hypnosis susceptibility levels contributed to this research. Using statistical analyses, it was concluded that, in highly hypnotizable people, the EEG phase synchronization between different paired channels, located on the frontal lobe, is significantly different from that in subjects with medium or low hypnotizability. PMID:22439789

Baghdadi, G; Nasrabadi, A M



Robotic stereo EEG in epilepsy surgery assessment.  


Epilepsy surgery remains the only chance of becoming seizure-free for many patients with focal epilepsies refractory to medical treatment. In those cases where plan of surgery cannot be formulated on the basis of non-invasive studies (MRI, scalp videotelemetry, neuropsycholgy, CT PET, MEG), intracranial EEG (ICEEG) recording can often identify seizure onset zone and make surgery possible. In the UK, the most commonly used ICEEG technique is implantation of subdural grids/strips+depth electrodes, the latter usually implanted into the mesial temporal structures. Until recently electrocorticography using subdural grids/strips combined with mesial temporal depth electrodes was routinely used in our centre. Since November 2011 we have switched to stereoEEG (sEEG) technique with robotic stereotactic implantation of multiple depth electrodes using Renishaw Neuromate robot. So far we have carried out sEEG implantation in 11 cases. The indications for sEEG included:Non-lesional TLE (n=4) Focal cortical dysplasia in proximity to eloquent cortex, e.g. L frontal lobe close to the motor strip or parietal lobe close to the primary sensory cortex (n=2) Dual pathology (n=1) Multiple lesions (tuberous sclerosis) (n=1) Bitemporal epilepsy (n=1) Re-investigation of previous unsuccessful resection (n=2) SEEG identified seizure onset zone in 10/11 of patients. In 1 patient (tuberous sclerosis with multiple tubers) ICEEG data were not sufficient to proceed to surgery and further studies are pending. Seven patients have undergone surgery and 3 patients are awaiting surgery. Seizure-free (Engel I) outcome has been seen in 5/7 patients who had surgery (follow up period 5-14 months, mean 9.8 months). In one case of bitemporal epilepsy (80% seizures originating in one temporal lobe and associated with ictal asystole), where surgery was undertaken with palliative intent, Engel III outcome has been seen. In 1 case only subjective events have been reported (possible non-epileptic attacks, awaiting further evaluation). No surgical complications of sEEG have been seen. The procedure is very well tolerated. The average time of recording (including stimulation studies) has been 9 days. Robotic sEEG has been a safe intracranial EEG technique that permits exploration of remote/ discontinuous brain regions and, importantly, the deep structures not accessible to subdural grid recording. Its advantages include:no need for craniotomy well tolerated by patients low risk of infection and bleeding complications electrodes can be removed and surgery planned electively at a later date it can be carried out in patients with history of previous subdural grid implantation/ neurosurgery The disadvantages are that cortical stimulation studies may be more limited (relative disadvantage) and the need for specialised equipment (expense). PMID:24108876

Sieradzan, Katarzyna; Sandeman, David; Smith, Shelagh; Trippick, Kathy; Johnson, Claire



EEG responses to tonic heat pain  

Microsoft Academic Search

The aim of the present study was to characterize the EEG response pattern specific for tonic pain which is an experimental pain model resembling clinical pain more closely than phasic pain. Tonic experimental pain was produced by a series of heat pulses 1C above pain threshold over 10 min. A series of heat pulses 0.3C below pain threshold and a constant

M. T. Huber; J. Bartling; D. Pachur; S. v. Woikowsky-Biedau; S. Lautenbacher



Frontal midline EEG dynamics during working memory  

Microsoft Academic Search

We show that during visual working memory, the electroencephalographic (EEG) process producing 5–7 Hz frontal midline theta (fm?) activity exhibits multiple spectral modes involving at least three frequency bands and a wide range of amplitudes. The process accounting for the fm? increase during working memory was separated from 71-channel data by clustering on time\\/frequency transforms of components returned by independent

Julie Onton; Arnaud Delorme; Scott Makeig



All-night EEG spectral analysis as a tool for the prediction of clinical response to antidepressant treatment.  


Earlier investigations have suggested that variables derived from quantified electroencephalographic (EEG) sleep analysis might predict good clinical response in an early phase of antidepressant treatment. In this report we evaluate the predictive value of all-night sleep EEG spectral analysis during the washout period before treatment. We compared the spectral EEG sleep profiles of major depressed inpatients divided into two groups according to an improvement > or = 50% on the Hamilton Rating Scale for Depression. Findings in this population demonstrate the presence of specific characteristics of the responder group compared with the nonresponder group. Delta band relative power was increased in the former group, while theta, alpha, and beta relative power were decreased. All the bands showed decrease in absolute power in the responder group. These results can be interpreted as enhanced sleep intensity in the responder group. All-night sleep EEG spectral variables are valid baseline markers of the functional differences between treatment responders and nonresponders and thus might permit prediction of clinical outcome. PMID:7578656

Luthringer, R; Minot, R; Toussaint, M; Calvi-Gries, F; Schaltenbrand, N; Macher, J P



EEG DeNoising Based on Wavelet Transformation  

Microsoft Academic Search

EEG is one of the mini-voltages. In order to improve the performance of EEG and increase the measure efficiency, we must eliminate the noise in EEG. Wavelet transformation is a kind of analytical tool in time-scale domain. It has the feature of multi-resolution analysis and the adaptation characteristic for signal. A noise rejection method with wavelet transformation was proposed here

Lanlan Yu



Scalp electrode impedance, infection risk, and EEG data quality  

Microsoft Academic Search

Objectives: Breaking the skin when applying scalp electroencephalographic (EEG) electrodes creates the risk of infection from blood-born pathogens such as HIV, Hepatitis-C, and Creutzfeldt–Jacob Disease. Modern engineering principles suggest that excellent EEG signals can be collected with high scalp impedance (?40 k?) without scalp abrasion. The present study was designed to evaluate the effect of electrode-scalp impedance on EEG data

Thomas C Ferree; Phan Luu; Gerald S Russell; Don M Tucker



Multiresolution of Clinical EEG Recordings Based on Wavelet Packet Analysis  

Microsoft Academic Search

Method for extracting the specified rhythms of clinical electroencephalogram (EEG) is proposed using the wavelet packet decomposition.\\u000a Based on the ability of accurately resolving the signal into desired time-frequency components, EEG signals are preprocessed\\u000a and decomposed into a series of rhythms for many clinical applications. Specified dynamic EEG rhythms can be accurately filtered\\u000a with designed wavelet structure. In addition, we

Lisha Sun; Guoliang Chang; Patch J. Beadle



ERPs correlates of EEG relative beta training in ADHD children  

Microsoft Academic Search

Eighty-six children (ages 9–14) with attention deficit hyperactivity disorder (ADHD) participated in this study. Event-related potentials (ERPs) were recorded in auditory GO\\/NOGO task before and after 15–22 sessions of EEG biofeedback. Each session consisted of 20 min of enhancing the ratio of the EEG power in 15–18 Hz band to the EEG power in the rest of spectrum, and 7–10

Jury D. Kropotov; Vera A. Grin-Yatsenko; Valery A. Ponomarev; Leonid S. Chutko; Elena A. Yakovenko; Inna S. Nikishena



Transfer Function between EEG and BOLD Signals of Epileptic Activity.  


Simultaneous electroencephalogram (EEG)-functional Magnetic Resonance Imaging (fMRI) recordings have seen growing application in the evaluation of epilepsy, namely in the characterization of brain networks related to epileptic activity. In EEG-correlated fMRI studies, epileptic events are usually described as boxcar signals based on the timing information retrieved from the EEG, and subsequently convolved with a hemodynamic response function to model the associated Blood Oxygen Level Dependent (BOLD) changes. Although more flexible approaches may allow a higher degree of complexity for the hemodynamics, the issue of how to model these dynamics based on the EEG remains an open question. In this work, a new methodology for the integration of simultaneous EEG-fMRI data in epilepsy is proposed, which incorporates a transfer function from the EEG to the BOLD signal. Independent component analysis of the EEG is performed, and a number of metrics expressing different models of the EEG-BOLD transfer function are extracted from the resulting time courses. These metrics are then used to predict the fMRI data and to identify brain areas associated with the EEG epileptic activity. The methodology was tested on both ictal and interictal EEG-fMRI recordings from one patient with a hypothalamic hamartoma. When compared to the conventional analysis approach, plausible, consistent, and more significant activations were obtained. Importantly, frequency-weighted EEG metrics yielded superior results than those weighted solely on the EEG power, which comes in agreement with previous literature. Reproducibility, specificity, and sensitivity should be addressed in an extended group of patients in order to further validate the proposed methodology and generalize the presented proof of concept. PMID:23355832

Leite, Marco; Leal, Alberto; Figueiredo, Patrícia



Sensitivity of scalp 10-20 EEG and magnetoencephalography.  


Although previous studies have investigated the sensitivity of electroencephalography (EEG) and magnetoencephalography (MEG) to detect spikes by comparing simultaneous recordings, there are no published reports that focus on the relationship between spike dipole orientation or sensitivity of scalp EEG/MEG and the "gold standard" of intracranial recording (stereotactic EEG). We evaluated two patients with focal epilepsy; one with lateral temporal focus and the other with insular focus. Two MEG recordings were performed for both patients, each recorded simultaneously with initially scalp EEG, based on international 10-20 electrode placement with additional electrodes for anterior temporal regions, and subsequently stereotactic EEG. Localisation of MEG spike dipoles from both studies was concordant and all MEG spikes were detected by stereotactic EEG. For the patient with lateral temporal epilepsy, spike sensitivity of MEG and scalp EEG (relative to stereotactic EEG) was 55 and 0%, respectively. Of note, in this case, MEG spike dipoles were oriented tangentially to scalp surface in a tight cluster; the angle of the spike dipole to the vertical line was 3.6 degrees. For the patient with insular epilepsy, spike sensitivity of MEG and scalp EEG (relative to stereotactic EEG) was 83 and 44%, respectively; the angle of the spike dipole to the vertical line was 45.3 degrees. For the patient with lateral temporal epilepsy, tangential spikes from the lateral temporal cortex were difficult to detect based on scalp 10-20 EEG and for the patient with insular epilepsy, it was possible to evaluate operculum insular sources using MEG. We believe that these findings may be important for the interpretation of clinical EEG and MEG. PMID:23531601

Kakisaka, Yosuke; Alkawadri, Rafeed; Wang, Zhong I; Enatsu, Rei; Mosher, John C; Dubarry, Anne-Sophie; Alexopoulos, Andreas V; Burgess, Richard C



Cortical sources of resting state electroencephalographic alpha rhythms deteriorate across time in subjects with amnesic mild cognitive impairment.  


Cortical sources of resting state electroencephalographic (EEG) rhythms are abnormal in subjects with mild cognitive impairment (MCI). Here, we tested the hypothesis that these sources in amnesic MCI subjects further deteriorate over 1 year. To this aim, the resting state eyes-closed EEG data were recorded in 54 MCI subjects at baseline (Mini Mental State Examination I = 26.9; standard error [SE], 0.2) and at approximately 1-year follow-up (13.8 months; SE, 0.5; Mini Mental State Examination II = 25.8; SE, 0.2). As a control, EEG recordings were also performed in 45 normal elderly and in 50 mild Alzheimer's disease subjects. EEG rhythms 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), and beta2 (20-30 Hz). Cortical EEG sources were estimated using low-resolution brain electromagnetic tomography. Compared with the normal elderly and mild Alzheimer's disease subjects, the MCI subjects were characterized by an intermediate power of posterior alpha1 sources. In the MCI subjects, the follow-up EEG recordings showed a decreased power of posterior alpha1 and alpha2 sources. These results suggest that the resting state EEG alpha sources were sensitive-at least at the group level-to the cognitive decline occurring in the amnesic MCI group over 1 year, and might represent cost-effective, noninvasive and widely available markers to follow amnesic MCI populations in large clinical trials. PMID:23906617

Babiloni, Claudio; Del Percio, Claudio; Lizio, Roberta; Marzano, Nicola; Infarinato, Francesco; Soricelli, Andrea; Salvatore, Elena; Ferri, Raffaele; Bonforte, Cinzia; Tedeschi, Gioacchino; Montella, Patrizia; Baglieri, Annalisa; Rodriguez, Guido; Famà, Francesco; Nobili, Flavio; Vernieri, Fabrizio; Ursini, Francesca; Mundi, Ciro; Frisoni, Giovanni B; Rossini, Paolo M



aEEG in preterm infants.  


Over the last decade, the survival of premature babies has improved dramatically. Such infants, especially those with extremely low birth weight, are still affected by dangerous complications occurring during the neonatal period that often cause brain damage. Intraventricular-intraparenchymal haemorrhage (IVH-IPH), periventricular leukomalacia (PVL), seizures, meningitis and hypoxic-ischaemic encephalopathy are the most common complications. Such problems require more specialized monitoring of brain function during this critical period. In recent years, many studies on very premature infants have shown that aEEG has a high predictive value for both short-term and long-term outcome. In fact, it has been proven that some types of background activity patterns, the absence of a sleep-wake cycle, and seizure activity are related to the onset of early complications such as IVH-IPH and PVL. Most recent studies have shown that an aEEG performed in the early hours or during the first days of life can predict the neurobehavioural development of preterm infants at 2 years and 3 years (Bayley Scale). In particular our study demonstrates that loss of sleep-wake cycling, shown by aEEG, has a high positive predictive value for the development of posthaemorrhagic hydrocephalus (PPH) in preterm infants with IVH; therefore, the study of cerebral background activity and in particular of sleep-wake cycling can be used as an early prognostic tool in patients at risk of PPH. PMID:22958046

Scoppa, A; Casani, A; Cocca, F; Coletta, C; De Luca, M G; Di Manso, G; Grappone, L; Pozzi, N; Orfeo, L



EEG frequency changes during sleep apneas.  


To study the effect of transient, apnea-induced hypoxemia on electrocortical activity, five patients with severe obstructive sleep apnea syndrome (OSAS) were investigated during nocturnal sleep. Polysomnographic and simultaneous digitized electro encephalographic (EEG) recordings for topographic and compressed spectral array analysis were made. The EEG recordings were timed exactly to respiratory events. During nonrapid eye movement (NREM) apnea, delta band amplitude increased, starting on average 13 seconds after the apnea onset. Average differences were 268% between initial and maximal values and 202% between initial and final values. In contrast, significant increases in delta amplitudes between the onset and end of REM apneas did not occur, although some caused deep oxygen desaturations. Changes in delta activity were not correlated to NREM apnea duration or degree of desaturation. These results indicate that the increased delta activity during NREM apneas may not be caused by arterial hypoxemia. It could instead be due to either an arousal mechanism, since arousals may be preceded by slow waves in EEG, or to a breakthrough of slow-wave-sleep activity. The sleep disturbance in severe OSAS may create such a propensity for slow-wave sleep that stages pass much more rapidly than in normal persons. PMID:8723384

Svanborg, E; Guilleminault, C



Automatic detection of EEG artefacts arising from head movements using EEG and gyroscope signals.  


Contamination of EEG signals by artefacts arising from head movements has been a serious obstacle in the deployment of automatic neurological event detection systems in ambulatory EEG. In this paper, we present work on categorizing these head-movement artefacts as one distinct class and on using support vector machines to automatically detect their presence. The use of additional physical signals in detecting head-movement artefacts is also investigated by means of support vector machines classifiers implemented with gyroscope waveforms. Finally, the combination of features extracted from EEG and gyroscope signals is explored in order to design an algorithm which incorporates both physical and physiological signals in accurately detecting artefacts arising from head-movements. PMID:23018030

O'Regan, Simon; Faul, Stephen; Marnane, William



What does cyclicity on amplitude-integrated EEG mean?  


In the context of amplitude-integrated electroencephalography (aEEG), the term 'sleep-wake cycling' (SWC), which is frequently used by clinicians and researchers, should be changed to 'cyclicity'. SWC is a technical term that refers to the biological pattern of alternating sleeping and waking states, which is difficult to define with only aEEG and no physical parameters. Additionally, the absence of cyclicity on aEEG is a more robust reflection of the sequence of the suppressed background patterns of an aEEG following cerebral injury or dysfunction than are sleep/wake states. PMID:22441113

Kidokoro, H; Inder, T; Okumura, A; Watanabe, K



A robust algorithm for removing artifacts in EEG recorded during FMRI/EEG study.  


The main purpose of this study was to propose a robust algorithm for removing artifacts from the electroencephalographic (EEG) data collected during magnetic resonance imaging (MRI). The core idea of the proposed method was to remove the main gradient artifacts by the maximum cross-correlation method and to remove the residual artifacts by the rolling-ball algorithm and lowpass filtering. The results showed that the proposed algorithm had a better performance and was robust in the sense that its performance was maintained when the sampling rate of EEG data was decreased from 10KHz to 200Hz. PMID:22277595

Huang, Chih-Hsu; Ju, Ming-Shaung; Lin, Chou-Ching K



The sleep EEG's microstructure in depression: alterations of the phase relations between EEG rhythms during REM and NREM sleep  

Microsoft Academic Search

Objective: We investigated the microstructure of sleep electroencephalograms (EEGs) of 13 unmedicated depressive inpatients and 13 healthy controls matched in sex and age, hypothesizing that depressives depict an alteration of certain EEG oscillations across the night.Methods: We digitized the sleep EEGs with a sampling rate of 100Hz (bipolar derivation Cz–Pz, 1440 single sweeps; 2048 data points each), calculated the time

Joachim Röschke; Klaus Mann



Visual stimulation elicits locked and induced gamma oscillations in monkey intracortical- and EEG-potentials, but not in human EEG  

Microsoft Academic Search

Stimulus-related fast oscillations in the ?-range (30–100 Hz) were clearly demonstrated with microelectrode recordings in\\u000a visual cortex of awake monkeys, and they were also reported for recordings of human electroencephalograms (EEG). However,\\u000a the presence of stimulus-related ?-modulation in human EEG has repeatedly been disputed. To clarify this dispute, we recorded\\u000a the scalp EEG of man and monkey as well as

Egbert Juergens; Andreas Guettler; Reinhard Eckhorn



Concurrent validity and reliability of lower and upper alpha activities as measures of visual and kinesthetic imagery ability  

Microsoft Academic Search

The purpose of this study was to correlate lower and upper alpha power with the Revised Movement Imagery Questionnaire (MIQ?R; Hall & Martin, 1997) to determine the validity of electroencephalographic (EEG) recordings as measures of kinesthetic and visual imagery ability. EEG activity was recorded from 30 right?handed?volunteers. Results revealed that the internal consistency and the test?retest reliability of both kinesthetic

J. Gualberto Cremades; Dale G. Pease



Noisy Galvanic Vestibular Stimulation Modulates the Amplitude of EEG Synchrony Patterns  

PubMed Central

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 and motor effects of vestibular stimulation, and noisy galvanic vestibular stimulation may provide an additional non-invasive means for neuromodulation of functional brain networks.

Kim, Diana J.; Yogendrakumar, Vignan; Chiang, Joyce; Ty, Edna; Wang, Z. Jane; McKeown, Martin J.



Noisy galvanic vestibular stimulation modulates the amplitude of EEG synchrony patterns.  


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 and motor effects of vestibular stimulation, and noisy galvanic vestibular stimulation may provide an additional non-invasive means for neuromodulation of functional brain networks. PMID:23874865

Kim, Diana J; Yogendrakumar, Vignan; Chiang, Joyce; Ty, Edna; Wang, Z Jane; McKeown, Martin J



Ecological validity of neurofeedback: modulation of slow wave EEG enhances musical performance.  


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

Egner, Tobias; Gruzelier, John H



Genetically altered mice: phenotypes, no phenotypes, and Faux phenotypes  

Microsoft Academic Search

Phenotype’ means different things, but whatever the measure, phenotype can be profoundly influenced by genetic, environmental\\u000a and infectious variables. The laboratory mouse is a complex multisystemic organism which, despite its genetically inbred nature,\\u000a as highly variable pathophysiologic characteristics. Mouse strains have background characteristics that can influence genomics\\u000a research. In addition to the mouse itself, different approaches toward creating mutant mice

Stephen W. Barthold


Developmental Trajectories of Resting EEG Power: An Endophenotype of Autism Spectrum Disorder  

PubMed Central

Current research suggests that autism spectrum disorder (ASD) is characterized by asynchronous neural oscillations. However, it is unclear whether changes in neural oscillations represent an index of the disorder or are shared more broadly among both affected and unaffected family members. Additionally, it remains unclear how early these differences emerge in development and whether they remain constant or change over time. In this study we examined developmental trajectories in spectral power in infants at high- or low-risk for ASD. Spectral power was extracted from resting EEG recorded over frontal regions of the scalp when infants were 6, 9, 12, 18 and 24 months of age. We used multilevel modeling to assess change over time between risk groups in the delta, theta, low alpha, high alpha, beta, and gamma frequency bands. The results indicated that across all bands, spectral power was lower in high-risk infants as compared to low-risk infants at 6-months of age. Furthermore high-risk infants showed different trajectories of change in spectral power in the subsequent developmental window indicating that not only are the patterns of change different, but that group differences are dynamic within the first two years of life. These findings remained the same after removing data from a subset of participants who displayed ASD related behaviors at 24 or 36 months. These differences in the nature of the trajectories of EEG power represent important endophenotypes of ASD.

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



Brain Activity in Predictive Sensorimotor Control for Landings: an EEG Pilot Study.  


Landing from a jump is related to predictive sensorimotor control. Frontal, central and parietal brain areas are known to play a role in this process based on online sensory feedback. This can be measured by EEG. However, there is only limited knowledge about brain activity during predictive preparation for drop landings (DL). The purpose is to demonstrate changes in brain activity in preparation for DL in different conditions. After resting, 10 athletes performed a series of DLs and were asked to concentrate on the landing preparation for 10 s before an auditory signal required them to drop land from a 30 cm platform. This task was executed before and after a standardized fatigue protocol. EEG spectral power was calculated during DL preparation. Frontal Theta power was increased during preparation compared to rest. Parietal Alpha-2 power demonstrated higher values in preparation after fatigue condition while lower limb kinematics remained unchanged. Cortical activity in frontal and parietal brain areas is sensitive for predictive sensorimotor control of drop landings. Frontal Theta power demonstrates an increase and is related to higher attentional control. In a fatigued condition the parietal Alpha-2 power increase might be related to a deactivation in the somatosensory brain areas. PMID:23740338

Baumeister, J; von Detten, S; van Niekerk, S-M; Schubert, M; Ageberg, E; Louw, Q A



Eye contact with neutral and smiling faces: effects on autonomic responses and frontal EEG asymmetry  

PubMed Central

In our previous studies we have shown that seeing another person “live” with a direct vs. averted gaze results in enhanced skin conductance responses (SCRs) indicating autonomic arousal and in greater relative left-sided frontal activity in the electroencephalography (asymmetry in the alpha-band power), associated with approach motivation. In our studies, however, the stimulus persons had a neutral expression. In real-life social interaction, eye contact is often associated with a smile, which is another signal of the sender's approach-related motivation. A smile could, therefore, enhance the affective-motivational responses to eye contact. In the present study, we investigated whether the facial expression (neutral vs. social smile) would modulate autonomic arousal and frontal EEG alpha-band asymmetry to seeing a direct vs. an averted gaze in faces presented “live” through a liquid crystal (LC) shutter. The results showed that the SCRs were greater for the direct than the averted gaze and that the effect of gaze direction was more pronounced for a smiling than a neutral face. However, in this study, gaze direction and facial expression did not affect the frontal EEG asymmetry, although, for gaze direction, we found a marginally significant correlation between the degree of an overall bias for asymmetric frontal activity and the degree to which direct gaze elicited stronger left-sided frontal activity than did averted gaze.

Ponkanen, Laura M.; Hietanen, Jari K.



Biophysical model for integrating neuronal activity, EEG, fMRI and metabolism.  


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

Sotero, Roberto C; Trujillo-Barreto, Nelson J



Tobacco Smoking Produces Widespread Dominant Brain Wave Alpha Frequency Increases  

PubMed Central

The major pharmacological ingredient in tobacco smoke is nicotine, a mild stimulant known to alter brain electrical activity. The object of this study was to determine if tobacco smoking in humans produces localized or widespread neocortical dominant alpha electroencephalographic (EEG) frequency increases consistent with nicotine stimulation of the brainstem activating system in animals. Twenty-two male volunteer non-deprived tobacco smokers were studied. They were asked not to smoke for at least 1 hr before the experiment in mid-morning as part of their usual smoking schedule. In the laboratory, they sham smoked and then smoked their favorite tobacco cigarette. Two experimental sessions (#1 and #2) were conducted, separated by a one to two month interval. In both sessions, there were minor statistically significant increases in the dominant alpha frequencies after sham smoking. In both sessions, after the subjects smoked a favorite tobacco cigarette there was a significant generalized increase in dominant alpha EEG frequencies in most scalp recording sites. This study demonstrates that tobacco smoking produces widespread bilateral neocortical increases in dominant alpha EEG frequencies consistent with the stimulant effects of nicotine on the brainstem reticular activating system.

Domino, Edward F.; Ni, Lisong; Thompson, Michael; Zhang, Huilea; Shikata, Hiroki; Fukai, Hiromi; Sakaki, Takeshi; Ohya, Ippei



Standardized Computer-based Organized Reporting of EEG: SCORE  

PubMed Central

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 possible the build-up of a multinational database, and it will help in training young neurophysiologists.

Beniczky, Sandor; Aurlien, Harald; Br?gger, Jan C; Fuglsang-Frederiksen, Anders; Martins-da-Silva, Antonio; Trinka, Eugen; Visser, Gerhard; Rubboli, Guido; Hjalgrim, Helle; Stefan, Hermann; Rosen, Ingmar; Zarubova, Jana; Dobesberger, Judith; Alving, J?rgen; Andersen, Kjeld V; Fabricius, Martin; Atkins, Mary D; Neufeld, Miri; Plouin, Perrine; Marusic, Petr; Pressler, Ronit; Mameniskiene, Ruta; Hopfengartner, Rudiger; Emde Boas, Walter; Wolf, Peter



Standardized computer-based organized reporting of EEG: SCORE.  


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