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1

Interpreting EEG alpha activity.  

PubMed

Exploring EEG alpha oscillations has generated considerable interest, in particular with regards to the role they play in cognitive, psychomotor, psycho-emotional and physiological aspects of human life. However, there is no clearly agreed upon definition of what constitutes 'alpha activity' or which of the many indices should be used to characterize it. To address these issues this review attempts to delineate EEG alpha-activity, its physical, molecular and morphological nature, and examine the following indices: (1) the individual alpha peak frequency; (2) activation magnitude, as measured by alpha amplitude suppression across the individual alpha bandwidth in response to eyes opening, and (3) alpha "auto-rhythmicity" indices: which include intra-spindle amplitude variability, spindle length and steepness. Throughout, the article offers a number of suggestions regarding the mechanism(s) of alpha activity related to inter and intra-individual variability. In addition, it provides some insights into the various psychophysiological indices of alpha activity and highlights their role in optimal functioning and behavior. PMID:23701947

Bazanova, O M; Vernon, D

2014-07-01

2

EEG alpha power and intelligence  

Microsoft Academic Search

The hypothesis was tested whether alpha power in different subbands (lower-1, lower-2, and upper alpha) is selectively related to intelligence. For 74 subjects, the EEG was recorded during a resting session. Two different intelligence tests (LGT-3 and IST-70) were performed. We found a strong positive correlation between intelligence and alpha power. Large differences between the two intelligence tests and alpha

M. Doppelmayr; W. Klimesch; W. Stadler; D. Pöllhuber; C. Heine

2002-01-01

3

EEG Alpha Power and Intelligence.  

ERIC Educational Resources Information Center

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

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

2002-01-01

4

PSYCHOPHYSICS OF EEG ALPHA STATE DISCRIMINATION  

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. PMID:22800733

Frederick, Jon A.

2012-01-01

5

Association of EEG alpha variants and alpha power with alcohol dependence in Mexican American Young Adults  

PubMed Central

Several studies support an association between EEG voltage and alcohol dependence. However, the distribution of EEG variants also appears to differ depending on an individual’s ethnic heritage, suggesting significant genetic stratification of this EEG phenotype. The present study’s aims were to investigate the incidence of EEG alpha variants and spectral power in the alpha frequency range in Mexican American young adults based on gender, personal and family history of alcohol dependence. Clinical ratings (high, medium and low alpha voltage variants) and spectral characteristics of the EEG in the alpha frequency range (7.5–12 Hz) were investigated in young adult (age 18–25 yrs) Mexican American men (n=98) and women (n=138) who were recruited from the community. Nineteen percent (n=45) of the participants had a low voltage alpha EEG variant, 18% had a high voltage variant, and 63% had a medium voltage variant. There were no significant differences in the distribution of the EEG variants based on family history of alcohol dependence. There was a significant relationship between gender and the three alpha variants (chi square: = 9.7, df=2; p<0.008), and there were no male participants with alcohol dependence with high alpha variants (chi square: 5.8; df=2; p<0.056). Alcohol dependence, but not a family history of alcohol dependence, was associated with lower spectral power in the alpha frequency range in the right (F=4.4; df=1,96; p<0.04) and left (F=5.3; df=1,96; p<0.02) occipital areas in the men but not in the women. In conclusion, in this select population of Mexican American young adults, male gender and alcohol dependence are associated with an absence of high voltage alpha variants and lower alpha power in the EEG. These data suggest that EEG low voltage, a highly heritable trait, may represent an important endophenotype in male Mexican Americans that may aid in linking brain function with genetic factors underlying alcohol dependence in this ethnic group. PMID:17452295

Ehlers, Cindy L.; Phillips, Evelyn

2007-01-01

6

EEG alpha power and creative ideation.  

PubMed

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

Fink, Andreas; Benedek, Mathias

2014-07-01

7

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.

1974-01-01

8

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

SciTech Connect

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

Enoch, M.A.; Rohrbaugh, W.; Harris, C.R. [Washington School of Medicine, St. Louis, MO (United States)] [and others

1995-10-09

9

Where the BOLD signal goes when alpha EEG leaves  

Microsoft Academic Search

Previous studies using simultaneous EEG and fMRI recordings have yielded discrepant results regarding the topography of brain activity in relation to spontaneous power fluctuations in the alpha band of the EEG during eyes-closed rest. Here, we explore several possible explanations for this discrepancy by re-analyzing in detail our previously reported data. Using single subject analyses as a starting point, we

H. Laufs; John L. Holt; Robert Elfont; Michael Krams; Joseph S. Paul; K. Krakow; A. Kleinschmidt

2006-01-01

10

EEG Alpha Rhythms and Susceptibility to Hypnosis  

Microsoft Academic Search

DESPITE a rich literature of anecdotal and clinical material on the relationship of hypnosis to physiological functions, especially to events in the central nervous system, the research findings are highly equivocal. Most relevant studies have been concerned with shifts in brain wave patterns, as measured by the electroencephalogram (EEG). The studies have attempted to identify the underlying processes which accompany

Perry London; JOSEPH T. HART; MORRIS P. LEIBOVITZ

1968-01-01

11

EEG alpha activity and hallucinatory experience during sensory deprivation.  

PubMed

The relationship between hallucinatory experiences under sensory deprivation and EEG alpha activities was studied. Each of seven male students lived alone in an air conditioned, soundproof dark room for 72 hours. When hallucinatory experiences occurred, the students pressed a button at once. If they could not press the button during the experience, they were required to press it two times when the hallucinatory experience was finished. Spectral analysis was performed on the consecutive EEG samples from just before button-presses to 10 min. before them, and the average alpha band amplitudes were obtained for the four epochs (0-.5, .5-2, 2-5, 5-10 min.). For the single button-presses, the amplitude of alpha band increased 2 min. before the button-presses. Right-hemisphere EEG activation was observed in the occipital area for the double button-presses. The results suggest an association between the hallucinatory experiences under sensory deprivation and the amount of EEG alpha activity. PMID:1408599

Hayashi, M; Morikawa, T; Hori, T

1992-10-01

12

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. PMID:1885078

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

1991-01-01

13

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

1999-01-01

14

Finding thalamic BOLD correlates to posterior alpha EEG.  

PubMed

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

2012-11-15

15

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

Microsoft Academic Search

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

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

2004-01-01

16

Common and specific genetic influences on EEG power bands delta, theta, alpha, and beta  

Microsoft Academic Search

It is difficult to study the genetic basis of psychological function\\/dysfunction due to its etiological complexity. Instead, we studied a biological marker, EEG power, which is associated with various psychological phenotypes and is closer to gene function. Previous studies have consistently demonstrated high heritability of EEG band power, but less is known about how common or specific genes influence each

Brendan P Zietsch; Jonathan L Hansen; Narelle K Hansell; Gina M Geffen; Nicholas G Martin; Margaret J Wright

2007-01-01

17

Changes in EEG alpha power during simulated driving: a demonstration  

Microsoft Academic Search

The aim was to assess the suitability of EEG-based techniques to recording activity during a driving simulation task. To achieve this, an inexpensive driving simulator (comprising a steering wheel, pedals and gear shift) were made to function with a personal computer running ‘Need for Speed’ simulation software. Simulators of this type are both inexpensive and relatively realistic. The EEG was

Mark A Schier

2000-01-01

18

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

PubMed Central

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.

2013-01-01

19

Brain oscillations and human memory: EEG correlates in the upper alpha and theta band  

Microsoft Academic Search

The EEG was recorded while subjects judged whether sequentially presented feature-concept pairs are semantically congruent. Later and without prior warning they had to perform a semantic and episodic memory task. The results show that the upper alpha band is most sensitive to the encoding and processing of semantic information. It is only the upper alpha band that distinguishes between good

W. Klimesch; M. Doppelmayr; Th Pachinger; B. Ripper

1997-01-01

20

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

1999-01-01

21

Neonatal EEG\\/Sleep State Analyses: A Complex Phenotype of Developmental Neural Plasticity  

Microsoft Academic Search

Computer analyses of EEG\\/sleep states can be used as physiologic biomarkers of developmental neural plasticity. Frequency- and time-dependent signal processing strategies of cerebral and noncerebral measures can help test current theories of neuronal network maturation in terms of segregation and integration of short-distance versus long-distance neuronal connections throughout the neuroaxis. Specific phenotypic expressions of adaptive or maladaptive neuronal connectivity are

Mark S. Scher; Kenneth A. Loparo

2009-01-01

22

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

PubMed Central

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

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

2014-01-01

23

Induced alpha band power changes in the human EEG and attention  

Microsoft Academic Search

Induced alpha power (in a lower, intermediate and upper band) which is deprived from evoked electroencephalograph (EEG) activity was analyzed in an oddball task in which a warning signal (WS) preceded a target or non-target. The lower band, reflecting phasic alertness, desynchronizes only in response to the WS and target. The intermediate band, reflecting expectancy, desynchronizes about 1 s before

W. Klimesch; M. Doppelmayr; H. Russegger; T. Pachinger; J. Schwaiger

1998-01-01

24

EEG oscillations in the gamma and alpha range respond differently to spatial frequency  

Microsoft Academic Search

Physical properties of visual stimuli affect electrophysiological markers of perception. One important stimulus property is spatial frequency (SF). Therefore, we studied the influence of SF on human alpha (8–13Hz) and gamma (>30Hz) electroencephalographic (EEG) responses in a choice reaction task. Since real world images contain multiple SFs, an SF mixture was also examined. Event related potentials were modulated by SF

Ingo Fründ; Niko A. Busch; Ursula Körner; Jeanette Schadow; Christoph S. Herrmann

2007-01-01

25

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

ERIC Educational Resources Information Center

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

Lally, Marianne B.

26

EEG alpha synchronization is related to top-down processing in convergent and divergent thinking.  

PubMed

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 demands and to specific cognitive process involved in creative thinking. To this end, EEG was measured during a convergent and a divergent thinking task (i.e., creativity-related task) which once were processed involving low and once involving high internal processing demands. High internal processing demands were established by masking the stimulus (after encoding) and thus preventing further bottom-up processing. Frontal alpha synchronization was observed during convergent and divergent thinking only under exclusive top-down control (high internal processing demands), but not when bottom-up processing was allowed (low internal processing demands). We conclude that frontal alpha synchronization is related to top-down control rather than to specific creativity-related cognitive processes. Frontal alpha synchronization, which has been observed in a variety of different creativity tasks, thus may not reflect a brain state that is specific for creative cognition but can probably be attributed to high internal processing demands which are typically involved in creative thinking. PMID:21925520

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

2011-10-01

27

The time-course of EEG alpha power changes in creative ideation  

PubMed Central

Increases in EEG alpha power during creative ideation are among the most consistent findings in the neuroscientific study of creativity, but existing studies did not focus on time-related changes of EEG alpha activity patterns during the process of creative ideation so far. Since several cognitive processes are involved in the generation of creative ideas, different EEG correlates may result as a function of time. In this study we addressed this crucial point. Forty-five participants worked on the “Alternative Uses Task” while the EEG was recorded and changes in task-related power (relative to rest) in the upper-frequency band (10–12 Hz) for three isochronous time intervals of the idea generation period were determined. Alpha power changes during idea generation followed a characteristic time course: we found a general increase of alpha power at the beginning of idea generation that was followed by a decrease and finally by a re-increase of alpha prior to responding that was most pronounced at parietal and temporal sites of the right hemisphere. Additionally, the production of more original ideas was accompanied by increasing hemispheric asymmetry (more alpha in the right than left hemisphere) with increasing duration of the idea generation period. The observed time course of brain activity may reflect the progression of different but well-known stages in the idea generation process: that is the initial retrieval of common and old ideas followed by the actual generation of novel and more creative ideas by overcoming typical responses through processes of mental simulation and imagination. PMID:24860485

Schwab, Daniela; Benedek, Mathias; Papousek, Ilona; Weiss, Elisabeth M.; Fink, Andreas

2014-01-01

28

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

PubMed Central

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

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

2013-01-01

29

EEG-based Upper-Alpha Neurofeedback for Cognitive Enhancement in Major Depressive Disorder: A preliminary, uncontrolled study  

E-print Network

, attention deficit hyperactivity disorder (ADHD), and addictive disorders, among others (see [2], [3 memory, attention, and executive functions. I. INTRODUCTION Major depressive disorder (MDD) is oneEEG-based Upper-Alpha Neurofeedback for Cognitive Enhancement in Major Depressive Disorder

Minguez, Javier

30

Phase-Locking and Amplitude Modulations of EEG Alpha: Two Measures Reflect Different Cognitive Processes in a Working Memory Task  

Microsoft Academic Search

It has been demonstrated in numerous experiments that oscillatory EEG responses in the alpha frequency band (8Ð12 Hz) increase with memory load during the retention interval in working memory tasks. However, the findings diverge with respect to which measurement of alpha activity is influenced by memory processes. Here, we differentiate between evoked and total alpha activity in order to separate

Christoph S. Herrmann; Daniel Senkowski; Stefan Röttger

31

PRIORITY COMMUNICATIONS Thalamic Metabolic Rate Predicts EEG Alpha Power in  

E-print Network

. The hypothesis that the thalamus serves as a neuro- nal oscillator of alpha rhythms has been supported by studies. The thalamus was identified and drawn on each subject's MRI. The MRI was then co-registered to the corresponding PET scan and metabolic activity from the thalamus extracted. Thalamic activity was then correlated

Wisconsin at Madison, University of

32

The effect of alpha rhythm sleep on EEG activity and individuals' attention.  

PubMed

[Purpose] This study examined whether the alpha rhythm sleep alters the EEG activity and response time in the attention and concentration tasks. [Subjects and Methods] The participants were 30 healthy university students, who were randomly and equally divided into two groups, the experimental and control groups. They were treated using the Happy-sleep device or a sham device, respectively. All participants had a one-week training period. Before and after training sessions, a behavioral task test was performed and EEG alpha waves were measured to confirm the effectiveness of training on cognitive function. [Results] In terms of the behavioral task test, reaction time (RT) variations in the experimental group were significantly larger than in the control group for the attention item. Changes in the EEG alpha power in the experimental group were also significantly larger than those of the control group. [Conclusions] These findings suggest that sleep induced using the Happy-sleep device modestly enhances the ability to pay attention and focus during academic learning. PMID:24409009

Kim, Seon Chill; Lee, Myoung Hee; Jang, Chel; Kwon, Jung Won; Park, Joo Wan

2013-12-01

33

Tracking EEG changes in response to alpha and beta binaural beats.  

PubMed

A binaural beat can be produced by presenting two tones of a differing frequency, one to each ear. Such auditory stimulation has been suggested to influence behaviour and cognition via the process of cortical entrainment. However, research so far has only shown the frequency following responses in the traditional EEG frequency ranges of delta, theta and gamma. Hence a primary aim of this research was to ascertain whether it would be possible to produce clear changes in the EEG in either the alpha or beta frequency ranges. Such changes, if possible, would have a number of important implications as well as potential applications. A secondary goal was to track any observable changes in the EEG throughout the entrainment epoch to gain some insight into the nature of the entrainment effects on any changes in an effort to identify more effective entrainment regimes. Twenty two healthy participants were recruited and randomly allocated to one of two groups, each of which was exposed to a distinct binaural beat frequency for ten 1-minute epochs. The first group listened to an alpha binaural beat of 10 Hz and the second to a beta binaural beat of 20 Hz. EEG was recorded from the left and right temporal regions during pre-exposure baselines, stimulus exposure epochs and post-exposure baselines. Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG. Possible mediating factors are discussed and a number of recommendations are made regarding future studies, exploring entrainment effects from a binaural beat presentation. PMID:23085086

Vernon, D; Peryer, G; Louch, J; Shaw, M

2014-07-01

34

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

PubMed

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

Tumyalis, A V; Aftanas, L I

2014-04-01

35

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

SciTech Connect

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

Devinsky, O.; Sato, S.; Conwit, R.A.; Schapiro, M.B. (National Institute of Neurological Disorders and Stroke, Bethesda, MD (USA))

1990-01-01

36

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

PubMed Central

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

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

2007-01-01

37

The contribution of different frequency bands of fMRI data to the correlation with EEG alpha rhythm.  

PubMed

Alpha rhythm is a prominent EEG rhythm observed during resting state and is thought to be related to multiple cognitive processes. Previous simultaneous electroencephalography (EEG)/functional magnetic resonance imaging (fMRI) studies have demonstrated that alpha rhythm is associated with blood oxygen level dependent (BOLD) signals in several different functional networks. How these networks influence alpha rhythm respectively is unclear. The low-frequency oscillations (LFO) in spontaneous BOLD activity are thought to contribute to the local correlations in resting state. Recent studies suggested that either LFO or other components of fMRI can be further divided into sub-components on different frequency bands. We hypothesized that those BOLD sub-components characterized the contributions of different brain networks to alpha rhythm. To test this hypothesis, EEG and fMRI data were simultaneously recorded from 17 human subjects performing an eyes-close resting state experiment. EEG alpha rhythm was correlated with the filtered fMRI time courses at different frequency bands (0.01-0.08 Hz, 0.08-0.25 Hz, 0.01-0.027 Hz, 0.027-0.073 Hz, 0.073-0.198 Hz, and 0.198-0.25 Hz). The results demonstrated significant relations between alpha rhythm and the BOLD signals in the visual network and in the attention network at LFO band, especially at the very low frequency band (0.01-0.027 Hz). PMID:24275197

Zhan, Zhichao; Xu, Lele; Zuo, Tian; Xie, Dongliang; Zhang, Jiacai; Yao, Li; Wu, Xia

2014-01-16

38

The best of both worlds: Phase-reset of human EEG alpha activity and additive power contribute to ERP generation  

Microsoft Academic Search

Some authors have proposed that event-related potentials (ERPs) are generated by a neuronal response which is additive to and independent of ongoing activity, others demonstrated that they are generated by partial phase-resetting of ongoing activity. We investigated the relationship between event-related oscillatory activity in the alpha band and prestimulus levels of ongoing alpha activity on ERPs. EEG was recorded from

Byoung-Kyong Min; Niko A. Busch; Stefan Debener; Cornelia Kranczioch; Simon Hanslmayr; Andreas K. Engel; Christoph S. Herrmann

2007-01-01

39

Kinesthetic and vestibular information modulate alpha activity during spatial navigation: a mobile EEG study.  

PubMed

In everyday life, spatial navigation involving locomotion provides congruent visual, vestibular, and kinesthetic information that need to be integrated. Yet, previous studies on human brain activity during navigation focus on stationary setups, neglecting vestibular and kinesthetic feedback. The aim of our work is to uncover the influence of those sensory modalities on cortical processing. We developed a fully immersive virtual reality setup combined with high-density mobile electroencephalography (EEG). Participants traversed one leg of a triangle, turned on the spot, continued along the second leg, and finally indicated the location of their starting position. Vestibular and kinesthetic information was provided either in combination, as isolated sources of information, or not at all within a 2 × 2 full factorial intra-subjects design. EEG data were processed by clustering independent components, and time-frequency spectrograms were calculated. In parietal, occipital, and temporal clusters, we detected alpha suppression during the turning movement, which is associated with a heightened demand of visuo-attentional processing and closely resembles results reported in previous stationary studies. This decrease is present in all conditions and therefore seems to generalize to more natural settings. Yet, in incongruent conditions, when different sensory modalities did not match, the decrease is significantly stronger. Additionally, in more anterior areas we found that providing only vestibular but no kinesthetic information results in alpha increase. These observations demonstrate that stationary experiments omit important aspects of sensory feedback. Therefore, it is important to develop more natural experimental settings in order to capture a more complete picture of neural correlates of spatial navigation. PMID:24616681

Ehinger, Benedikt V; Fischer, Petra; Gert, Anna L; Kaufhold, Lilli; Weber, Felix; Pipa, Gordon; König, Peter

2014-01-01

40

Kinesthetic and vestibular information modulate alpha activity during spatial navigation: a mobile EEG study  

PubMed Central

In everyday life, spatial navigation involving locomotion provides congruent visual, vestibular, and kinesthetic information that need to be integrated. Yet, previous studies on human brain activity during navigation focus on stationary setups, neglecting vestibular and kinesthetic feedback. The aim of our work is to uncover the influence of those sensory modalities on cortical processing. We developed a fully immersive virtual reality setup combined with high-density mobile electroencephalography (EEG). Participants traversed one leg of a triangle, turned on the spot, continued along the second leg, and finally indicated the location of their starting position. Vestibular and kinesthetic information was provided either in combination, as isolated sources of information, or not at all within a 2 × 2 full factorial intra-subjects design. EEG data were processed by clustering independent components, and time-frequency spectrograms were calculated. In parietal, occipital, and temporal clusters, we detected alpha suppression during the turning movement, which is associated with a heightened demand of visuo-attentional processing and closely resembles results reported in previous stationary studies. This decrease is present in all conditions and therefore seems to generalize to more natural settings. Yet, in incongruent conditions, when different sensory modalities did not match, the decrease is significantly stronger. Additionally, in more anterior areas we found that providing only vestibular but no kinesthetic information results in alpha increase. These observations demonstrate that stationary experiments omit important aspects of sensory feedback. Therefore, it is important to develop more natural experimental settings in order to capture a more complete picture of neural correlates of spatial navigation. PMID:24616681

Ehinger, Benedikt V.; Fischer, Petra; Gert, Anna L.; Kaufhold, Lilli; Weber, Felix; Pipa, Gordon; König, Peter

2014-01-01

41

Alpha-1-antitrypsin phenotypes in adult liver disease patients  

PubMed Central

Alpha-1-antitrypsin (AAT) is an important serine protease inhibitor in humans. Hereditary alpha-1-antitrypsin deficiency (AATD) affects lungs and liver. Liver disease caused by AATD in paediatric patients has been previously well documented. However, the association of liver disease with alpha-1-antitrypsin gene polymorphisms in adults is less clear. Therefore, we aimed to study AAT polymorphisms in adults with liver disease. We performed a case-control study. AAT polymorphisms were investigated by isoelectric focusing in 61 patients with liver cirrhosis and 9 patients with hepatocellular carcinoma. The control group consisted of 218 healthy blood donors. A significant deviation of observed and expected frequency of AAT phenotypes from Hardy-Weinberg equilibrium (chi-square = 34.77, df 11, P = 0.000) in the patient group was caused by a higher than expected frequency of Pi ZZ homozygotes (f = 0.0143 and f = 0.0005, respectively, P = 0.000). In addition, Pi M homozygotes were more frequent in patients than in controls (63% and 46%, respectively, P = 0.025). Our study results show that Pi ZZ homozygosity in adults could be associated with severe liver disease. Presence of Pi M homozygosity could be associated with liver disease via some mechanism different from Z allele-induced liver damage through accumulation of AAT polymers. PMID:19961268

Alempijevic, Tamara; Milutinovic, Aleksandra Sokic; Kovacevic, Nada

2009-01-01

42

Mid-frontal EEG alpha asymmetries predict individual differences in one aspect of theory of mind: Mental state decoding  

Microsoft Academic Search

Mental state decoding is the aspect of theory-of-mind (ToM) reasoning that requires individuals to make judgments about others’ mental states based solely on immediately available information. We investigated whether individual differences in resting, task-independent frontal EEG alpha asymmetries predicted performance on the “Mind in the Eyes” (MIE) task, which is an established measure of mental state decoding skills. Group analyses

Mark A. Sabbagh; Jessica Flynn

2006-01-01

43

Association between COMT Val158Met genotype and EEG alpha peak frequency tested in two independent cohorts.  

PubMed

This study could not confirm the association between the Catechol-O-Methyltransferase Val158Met polymorphism (COMT) and electroencephalographic (EEG) alpha peak frequency (APF) in two independent cohorts of 187 (96 depressed and 91 healthy participants) and 413 healthy participants. If COMT and APF play a role in depression or antidepressant treatment response, they do not have a shared pathway. We emphasize the importance of publishing null-findings for obtaining more accurate overall estimates of genetic effects. PMID:24889847

Veth, Cornelis P M; Arns, Martijn; Drinkenburg, Wilhelmus; Talloen, Willem; Peeters, Pieter J; Gordon, Evian; Buitelaar, Jan K

2014-09-30

44

Increased EEG power density in alpha and theta bands in adult ADHD patients  

Microsoft Academic Search

This study examined EEG abnormalities in adults with attention deficit hyperactivity disorder (ADHD). We investigated EEG\\u000a frequencies in 34 adults with ADHD and 34 control subjects. Two EEG readings were taken over 5 min intervals during an eyes-closed\\u000a resting period with 21 electrodes placed in accordance with the international 10–20 system. Fourier transformation was performed\\u000a to obtain absolute power density in

S. Koehler; P. Lauer; T. Schreppel; C. Jacob; M. Heine; A. Boreatti-Hümmer; A. J. Fallgatter; M. J. Herrmann

2009-01-01

45

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

PubMed

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

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

2003-10-01

46

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. PMID:24187540

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

2013-01-01

47

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

PubMed Central

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

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

2008-01-01

48

Resting and task-elicited prefrontal EEG alpha asymmetry in depression: support for the capability model.  

PubMed

The capability model of frontal electroencephalographic (EEG) asymmetry suggests that brain activity during emotional challenge will be a more powerful indicator of predispositions toward psychopathology than activity observed at rest. EEG data were assessed during a resting baseline and a facial emotion task, wherein individuals with (n = 143) and without (n = 163) lifetime major depressive disorder (MDD) made approach (angry and happy) and withdrawal (afraid and sad) facial expressions. EEG asymmetry during emotional challenge was a more powerful indicator of MDD status than resting asymmetry for average, Cz, and linked mastoid references, results in support of the capability model. However, current-source-density (CSD) transformed asymmetry was indicative of lifetime MDD status under resting and task-elicited conditions. Findings suggest that CSD-transformed data may be more robust indicators of trait frontal EEG asymmetry. PMID:24611480

Stewart, Jennifer L; Coan, James A; Towers, David N; Allen, John J B

2014-05-01

49

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

50

Test-retest reliability of frontal alpha electroencephalogram (EEG) and electrocardiogram (ECG) measures in adolescents: a pilot study.  

PubMed

A number of studies have shown that the pattern of resting frontal EEG alpha power and asymmetry and heart rate are predictive of individual differences in affective style in children and adults. Although test-retest reliability of frontal electrocortical and autonomic measures has been established in adult and child and some clinical populations, few studies have examined test-retest reliability of these measures in adolescents. Here, we conducted a pilot study to examine the test-retest reliability of frontal EEG alpha power and asymmetry and heart period and heart rate in 10 typically developing adolescent participants (M age = 15.9 years) over a 1 month period. We found acceptable test-retest reliability using Pearson and intra-class correlations in left and right mid-frontal alpha power and asymmetry and heart period and heart rate over 1 month. These results provide initial evidence for acceptable levels of test-retest reliability in central and peripheral psychophysiological measures in adolescents used to index affective style in children and adults. Future studies are needed with a larger sample to ensure the reliability of these results. PMID:24617292

Winegust, Adira K; Mathewson, Karen J; Schmidt, Louis A

2014-12-01

51

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

2001-01-01

52

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

2009-01-01

53

Relations between PET-derived measures of thalamic glucose metabolism and EEG alpha power  

E-print Network

to mental activity and has subsequently been used as an indirect measure of brain activation. The thalamus have suggested that cortical alpha rhythms are correlated with alpha rhythms in the thalamus. However correlated with glucose metabolic activity in the thalamus. These data provide the first evidence

Wisconsin at Madison, University of

54

Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: new mutations and the paradox between genotype and phenotype.  

PubMed

Up to now eight patients with alpha-NAGA deficiency have been described. This includes the newly identified patient reported here who died unexpectedly aged 1 1/2 years of hypoxia during convulsions; necropsy was not performed. Three patients have been genotyped previously and here we report the mutations in the other five patients, including two new mutations (S160C and E193X). The newly identified patient is consanguineous with the first patients reported with alpha-NAGA deficiency and neuroaxonal dystrophy and they all had the alpha-NAGA genotype E325K/E325K. Clinical heterogeneity among patients with alpha-NAGA deficiency is extreme. Two affected sibs, homozygotes for E325K, are severely affected and have the signs and symptoms of infantile neuroaxonal dystrophy, but prominent vacuolisation is lacking. The mildly affected patients (two families, three patients) at the opposite end of the clinical spectrum have clear vacuolisation and angiokeratoma but no overt neurological manifestations. Two of them are homozygous for the stop mutation E193X, leading to complete loss of alpha-NAGA protein. These observations are difficult to reconcile with a simple genotype-phenotype correlation and we suggest that factors or genes other than alpha-NAGA contribute to the clinical heterogeneity of the eight patients with alpha-NAGA deficiency. At the metabolic level, the patients with alpha-NAGA deficiency are similar. The major abnormal urinary oligosaccharides are sialylglycopeptides of the O linked type. Our enzymatic studies indicated that these compounds are not the primary lysosomal storage products. PMID:8782044

Keulemans, J L; Reuser, A J; Kroos, M A; Willemsen, R; Hermans, M M; van den Ouweland, A M; de Jong, J G; Wevers, R A; Renier, W O; Schindler, D; Coll, M J; Chabas, A; Sakuraba, H; Suzuki, Y; van Diggelen, O P

1996-06-01

55

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. PMID:21779257

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

2011-01-01

56

The impact of audio-visual stimulation on alpha brain oscillations: An EEG study  

Microsoft Academic Search

Many studies investigated the brain responses as a reaction in auditory or visual stimuli separately. However a few studies have been published so far investigating the interactions of the two aforementioned stimuli. The current study comes to examine the impact of the audio-visual stimulation with binaural beats and flickering light in four different colors on low and upper alpha oscillations.

Christos N. Moridis; Manousos A. Klados; Ioannis A. Kokkinakis; Vasileios Terzis; Anastasios A. Economides; Anna Karlovasitou; Panagiotis D. Bamidis; Vasileios E. Karabatakis

2010-01-01

57

Prenatal skeletal dysplasia phenotype in severe MLII alpha/beta with novel GNPTAB mutation.  

PubMed

We report a neonate who was diagnosed as a case of skeletal dysplasia during pregnancy, and was subsequently diagnosed as a case of MLII alpha/beta on the basis of clinical and radiological findings and molecular testing of the parents. A novel GNPTAB mutation c.1701delC [p.F566LfsX5] was identified in the father. The case reiterates the severe prenatal phenotype of MLII alpha/beta which mimics skeletal dysplasia and illustrates the utility of molecular genetic analysis in confirmation of diagnosis and subsequent genetic counselling. PMID:24685522

Aggarwal, Shagun; Coutinho, Maria Francisca; Dalal, Ashwin B; Mohamed Nurul Jain, S Jamal; Prata, Maria João; Alves, Sandra

2014-06-01

58

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

PubMed Central

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 PiZZ genotype were assessed for history of chronic bronchitis, impairment of lung function and radiological presence of emphysema and bronchiectasis. A subset of subjects with 3 years consecutive lung function data was assessed for decline of lung function. Four single nucleotide polymorphisms (SNPs) tagging TNF? were genotyped using TaqMan® genotyping technologies and compared between subjects affected by each phenotype and those unaffected. Plasma TNF? levels were measured in all PiZZ subjects. Results All SNPs were in Hardy-Weinberg equilibrium. A significant difference in rs361525 genotype (p = 0.01) and allele (p = 0.01) frequency was seen between subjects with and without chronic bronchitis, independent of the presence of other phenotypes. TNF? plasma level showed no phenotypic or genotypic associations. Conclusion Variation in TNF? is associated with chronic bronchitis in AATD. PMID:18620570

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

2008-01-01

59

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

2012-01-01

60

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

PubMed

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 8-12 Hz) 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 athletes and 28 non-athletes during resting state eyes-closed and eyes-open conditions. The EEG data were spatially enhanced by surface Laplacian estimation. Cortical activity was indexed by task-related power decrease (TRPD), namely the alpha power during the eyes-open referenced to the eyes-closed resting condition. Low-frequency alpha TRPD (about 8-10 Hz) was lower in the elite karate athletes than in the non-athletes in frontal (p<0.00002), central (p<0.008) and right occipital (p<0.02) areas. Similarly, high-frequency alpha TRPD (about 10-12 Hz) was lower in the elite karate athletes than in the non-athletes in frontal (p<0.00009) and central (p<0.01) areas. These results suggest that athletes' brain is characterized by reduced cortical reactivity to eyes opening in the condition of resting state, in line with the "neural efficiency" hypothesis. The present study motivates future research evaluating the extent to which this general functional brain feature is related to heritable trait or intensive visuo-motor training of elite athletes. PMID:21945479

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

2011-12-01

61

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)

2011-06-21

62

Hypoxia and metabolic phenotypes during breast carcinogenesis: expression of HIF-1alpha, GLUT1, and CAIX.  

PubMed

Hypoxia and acidosis are microenvironmental selection forces during somatic evolution in breast carcinogenesis. The effect of cobalt chloride (CoCl(2))-induced hypoxia on the expression of hypoxia-inducible factor (HIF)-1alpha, glucose transporter 1 (GLUT1), and carbonic anhydrase IX (CAIX) was assessed in breast cancer cells derived from primary sites (HCC1395 and HCC1937) and metastatic sites (MCF-7 and MDA-MB-231) by reverse transcriptase-polymerase chain reaction and immunoblotting. We analyzed these proteins' expression in tissue samples from normal breast tissue, usual ductal hyperplasia (DH), atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC) using immunohistochemistry. CAIX mRNA was expressed constitutively in MDA-MB-231 cells but not in the other three cell lines. CAIX mRNA expression was increased after CoCl(2)-induced hypoxia in all four breast cancer cell lines. The expression of HIF-1alpha and GLUT1 proteins was increased after CoCl(2)-induced hypoxia in all breast cancer cell lines tested. Hypoxia significantly increased CAIX protein expression in primary cancer cells but not in metastatic ones. HIF-1alpha was not expressed in benign breast tissue, whereas it was significantly expressed in DH, ADH, DCIS, and IDC (p < 0.001). GLUT1 and CAIX were expressed only in DCIS (56.8% and 25.0%) and IDC (44.1% and 30.5%), with higher expression in high grade DCIS than low/intermediate grade DCIS (79.2% vs. 30.0%, p = 0.001 and 37.5% vs. 10.0%, p = 0.036, respectively). High CAIX expression was significantly associated with poor histological grade of IDC (p = 0.005). During breast carcinogenesis, the role of HIF-1alpha changes from response to proliferation to tumor progression. GLUT1 expression (glycolytic phenotype) and CAIX expression (acid-resistant phenotype) may result in a powerful adaptive advantage and represent an aggressive phenotype. PMID:20526721

Chen, Chi-Long; Chu, Jan-Show; Su, Wu-Chou; Huang, Soon-Cen; Lee, Wen-Ying

2010-07-01

63

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

PubMed Central

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

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

2012-01-01

64

Regional differences in trait-like characteristics of the waking EEG in early adolescence  

PubMed Central

Background The human waking EEG spectrum shows high heritability and stability and, despite maturational cortical changes, high test-retest reliability in children and teens. These phenomena have also been shown to be region specific. We examined the stability of the morphology of the wake EEG spectrum in children aged 11 to 13 years recorded over weekly intervals and assessed whether the waking EEG spectrum in children may also be trait-like. Three minutes of eyes open and three minutes of eyes closed waking EEG was recorded in 22 healthy children once a week for three consecutive weeks. Eyes open and closed EEG power density spectra were calculated for two central (C3LM and C4LM) and two occipital (O1LM and O2LM) derivations. A hierarchical cluster analysis was performed to determine whether the morphology of the waking EEG spectrum between 1 and 20 Hz is trait-like. We also examined the stability of the alpha peak using an ANOVA. Results The morphology of the EEG spectrum recorded from central derivations was highly stable and unique to an individual (correctly classified in 85% of participants), while the EEG recorded from occipital derivations, while stable, was much less unique across individuals (correctly classified in 42% of participants). Furthermore, our analysis revealed an increase in alpha peak height concurrent with a decline in the frequency of the alpha peak across weeks for occipital derivations. No changes in either measure were observed in the central derivations. Conclusions Our results indicate that across weekly recordings, power spectra at central derivations exhibit more “trait-like” characteristics than occipital derivations. These results may be relevant for future studies searching for links between phenotypes, such as psychiatric diagnoses, and the underlying genes (i.e., endophenotypes) by suggesting that such studies should make use of more anterior rather than posterior EEG derivations. PMID:24103323

2013-01-01

65

Parametric person identification from the EEG using computational geometry  

Microsoft Academic Search

Person identification based on features extracted parametrically from the EEG spectrum is investigated in this work. The method proposed utilizes computational geometry algorithms (convex polygon intersections), appropriately modified, in order to classify unknown EEGs. The signal processing step includes EEG spectral analysis for feature extraction, by fitting a linear model of the AR type on the alpha rhythm EEG signal.

M. Poulos; M. Rangoussi; V. Chrissikopoulos; A. Evangelou

1999-01-01

66

EEG synchronization and migraine  

NASA Astrophysics Data System (ADS)

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

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

2004-03-01

67

Phenotypic and functional markers for 1alpha,25-dihydroxyvitamin D(3)-modified regulatory dendritic cells.  

PubMed

The clinical use of dendritic cells (DCs) to induce antigen-specific immune tolerance has been hampered by the lack of a widely acknowledged method for generating human regulatory DCs but even more so by the non-existence of reliable markers. Thus, we set out to find reliable markers that can be measured with simple methods to identify regulatory DCs that are applicable for future clinical studies. Human DCs were generated from peripheral blood monocytes in the presence of 1alpha,25-dihydroxyvitamin D(3) (VD3), which gave rise to a phenotype that resembles immature DCs, with the exception of high CD14 and reduced CD1a on the cell surface. These VD3-treated DCs exert a long-lasting inefficient T cell stimulation and induce T cell hyporesponsiveness with regulatory potential. Importantly, such VD3-treated DCs were readily distinguishable from untreated DCs by low levels of interleukin-23 secretion and low expression of miR-155 upon exposure to maturation stimuli. Furthermore, VD3-treated DCs showed over-expression of miR-378. All these features can be used as robust markers for quality control of VD3-treated regulatory DCs in future clinical studies. PMID:19659770

Pedersen, A W; Holmstrøm, K; Jensen, S S; Fuchs, D; Rasmussen, S; Kvistborg, P; Claesson, M H; Zocca, M-B

2009-07-01

68

Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: new mutations and the paradox between genotype and phenotype  

Microsoft Academic Search

Up to now eight patients with alpha-NAGA deficiency have been described. This includes the newly identified patient reported here who died unexpectedly aged 1 1\\/2 years of hypoxia during convulsions; necropsy was not performed. Three patients have been genotyped previously and here we report the mutations in the other five patients, including two new mutations (S160C and E193X). The newly

J. L. M. Keulemans; A. J. J. Reuser; M. A. Kroos; R. Willemsen; M. M. P. Hermans; A. M. W. van den Ouweland; J. G. N. de Jong; R. A. Wevers; W. O. Renier; D. Schindler; M. J. Coll; A. Chabas; H. Sakuraba; Y. Suzuki; O. P. van Diggelen

1996-01-01

69

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. PMID:21554732

2011-01-01

70

Expression of mutant alpha-synuclein modulates microglial phenotype in vitro  

Microsoft Academic Search

Background  Increased reactive microglia are a histological characteristic of Parkinson's disease (PD) brains, positively correlating\\u000a with levels of deposited ?-synuclein protein. This suggests that microglial-mediated inflammatory events may contribute to\\u000a disease pathophysiology. Mutations in the gene coding for ?-synuclein lead to a familial form of PD. Based upon our prior\\u000a findings that ?-synuclein expression regulates microglial phenotype we hypothesized that expression

Lalida Rojanathammanee; Eric J Murphy; Colin K Combs

2011-01-01

71

Test-retest reliability of cognitive EEG  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

72

Investigation of the modulation between EEG alpha waves and slow/fast delta waves in children in different depths of Desflurane anesthesia  

E-print Network

in different depths of Desflurane anesthesia Behnam Molaee-Ardekani1,2,3, , Mohammad-Bagher Shamsollahi3-band EEG activities in various depths of anesthesia (DOA). Methods: This modulation, which is a sort anesthesia. Two parameters are defined to quantify the modulation: strength of modulation (SOM) and phase

Paris-Sud XI, Université de

73

Phenotypic characterization of an alpha 4 neuronal nicotinic acetylcholine receptor subunit knock-out mouse.  

PubMed

Neuronal nicotinic acetylcholine receptors (nAChR) are present in high abundance in the nervous system (Decker et al., 1995). There are a large number of subunits expressed in the brain that combine to form multimeric functional receptors. We have generated an alpha(4) nAChR subunit knock-out line and focus on defining the behavioral role of this receptor subunit. Homozygous mutant mice (Mt) are normal in size, fertility, and home-cage behavior. Spontaneous unconditioned motor behavior revealed an ethogram characterized by significant increases in several topographies of exploratory behavior in Mt relative to wild-type mice (Wt) over the course of habituation to a novel environment. Furthermore, the behavior of Mt in the elevated plus-maze assay was consistent with increased basal levels of anxiety. In response to nicotine, Wt exhibited early reductions in a number of behavioral topographies, under both unhabituated and habituated conditions; conversely, heightened levels of behavioral topographies in Mt were reduced by nicotine in the late phase of the unhabituated condition. Ligand autoradiography confirmed the lack of high-affinity binding to radiolabeled nicotine, cytisine, and epibatidine in the thalamus, cortex, and caudate putamen, although binding to a number of discrete nuclei remained. The study confirms the pivotal role played by the alpha(4) nAChR subunit in the modulation of a number of constituents of the normal mouse ethogram and in anxiety as assessed using the plus-maze. Furthermore, the response of Mt to nicotine administration suggests that persistent nicotine binding sites in the habenulo-interpeduncular system are sufficient to modulate motor activity in actively exploring mice. PMID:10964949

Ross, S A; Wong, J Y; Clifford, J J; Kinsella, A; Massalas, J S; Horne, M K; Scheffer, I E; Kola, I; Waddington, J L; Berkovic, S F; Drago, J

2000-09-01

74

Low normal alpha-1-antitrypsin serum concentrations and MZ-phenotype are associated with byssinosis and familial allergy in cotton mill workers.  

PubMed

Recent studies have shown a close association between byssinosis and airborne endotoxin concentrations. Endotoxin might induce byssinosis through the release of biochemical mediators as the broncheoalveolar surface. Alpha-1-antitrypsin (alpha-1-A) which neutralizes enzymes released by granulocytes is known to be important. This study evaluates the possible importance of alpha-1-A concentration and the heterozygosity (Pi-S and Pi-Z alleles), in the prevalence of byssinosis and familial allergy. 253 cotton workers were interviewed and clinically studied to identify persons with the cotton lung disease, byssinosis, and atopic disease. Serum was available for alpha-1-A concentration determination in 226 individuals, and for Pi phenotyping in 206. The overall prevalence of byssinosis was 30/226 (13%). In the group with alpha-1-A < or = 35 mumol l-1 the prevalence was 5/18 (28%), versus the prevalence 25/208 (12%) in the group with alpha-1-A > 35 mumol l-1 (p < 0.1, Fishers exact test). MZ phenotype was associated with an increased prevalence of byssinosis compared with the MM-group: 3/8 (38%) and 25/187 (13%), p < 0.1, Fishers exact test. An association between MZ-phenotype and familial allergy was found: 4/8 (50%) contra 23/187 (12%), p < 0.05, Fishers exact test. In a logistic regression model controlling for confounding by endotoxin, tobacco exposure, sex, and age, the odds ratio for byssinosis in the MZ-phenotype group was significantly elevated 5.8 (1.1-30.3). Odds ratio for familial allergy was also significantly elevated in the MZ-group 2.8 (1.3-5.9).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7920693

Sigsgaard, T; Brandslund, I; Rasmussen, J B; Lund, E D; Varming, H

1994-06-01

75

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

PubMed

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

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

2014-02-01

76

EEG spectral analysis in delirium.  

PubMed Central

Spectral analysis of EEG was conducted for 51 elderly delirious patients meeting the Diagnostic and Statistical Manual of Mental Disorders III (DSM-III) criteria and for 19 controls. As a whole group, and also when subdivided according to the type of delirium, severity of cognitive decline or the type of central nervous system disease, delirious patients showed significant reductions of alpha percentage, increased theta and delta activity and slowing of the peak and mean frequencies and these changes were also obvious in individual recordings. The alpha percentage and various ratio parameters correlated significantly with Mini Mental State score, and delta percentage and mean frequency with the lengths of delirium and hospitalisation. The results indicate an association between spectral EEG changes and severity of cognitive deterioration in delirium. PMID:2795067

Koponen, H; Partanen, J; Paakkonen, A; Mattila, E; Riekkinen, P J

1989-01-01

77

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

PubMed Central

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

Kraus, Teresa; Cherry, Mohamad

2014-01-01

78

[Analysis of rhythm features of EEG for driving fatigue].  

PubMed

With extracting separately delta, theta, alpha and beta rhythms of electroencephalogram (EEG), we studied the characters of EEG for fatigued drivers by analyzing relative power spectrum, power spectral entropy and brain electrical activity mapping. The experimental results showed that with the average relative power spectrum in delta and theta rhythms of EEG increasing, the average relative power spectrum in alpha and beta rhythms decreased, while the average relative power spectrum in delta, theta and alpha rhythms increased in deep fatigue. The average power spectral entropy of EEG decreases with the increasing fatigue level. The average relative power spectrum and the average power spectral entropy of EEG could be expected to serve as the index for detecting fatigue level of drivers. PMID:23016405

Wang, Li; Ai, Lingmei; Wang, Siwang; Lwo, Wanzhi; Luo, Wanzhi

2012-08-01

79

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

2012-01-01

80

EEG correlates of Wechsler Adult Intelligence Scale.  

PubMed

It was recently shown that cognitive functions requiring more widespread brain integration relate to slower EEG activity, whereas cognitive performance supported by local brain integration is associated with faster EEG components (Von Stein & Sarnthein, 2000). Associations were studied between performance on WAIS and resting EEG spectral parameters in heroin abusers and normal young males. The most prominent associations between WAIS and EEG variables were consistently registered in polar and lateral frontal/temporal derivations. WAIS subtests predominantly loading on retrieval from long-term memory stores were significantly associated with delta bands mean frequencies. Subtests with strong working memory component related to theta2 mean frequency at temporal leads. Subtests requiring problem-solving operations correlated with alpha bands parameters, whereas psychomotor speed was associated with beta power. The data are in agreement with the hypothesis of Von Stein & Sarnthein (2000). PMID:16923691

Polunina, Anna G; Davydov, Dmitry M

2006-10-01

81

EEG changes during long-term treatment with donepezil in Alzheimer's disease patients  

Microsoft Academic Search

Summary.   In this pilot study, we examined the long-term treatment effect of donepezil on the quantitative EEG (qEEG) in 12 Alzheimer's\\u000a disease patients. The qEEGs of the mean absolute and relative amplitudes of betal, alpha, theta and delta activities were\\u000a obtained at baseline and during donepezil treatment. Comparisons of awake qEEG prior to and during treatment were performed\\u000a using a

E. A. Kogan; A. D. Korczyn; R. G. Virchovsky; S. Sh. Klimovizky; T. A. Treves; M. Y. Neufeld

2001-01-01

82

Polymorphisms of the tumor necrosis factor-alpha receptor 2 gene are associated with obesity phenotypes among 405 Caucasian nuclear families  

PubMed Central

The plasma level of the tumor necrosis factor-alpha receptor 2 (TNFR2) is associated with obesity phenotypes. However, the genetic polymorphisms for such an association have rarely been explored and are generally unknown. In this study, by employing a large sample of 1,873 subjects from 405 Caucasian nuclear families, we explored the association of 12 SNPs of the TNFR2 gene and obesity-related phenotypes, including body mass index (BMI), fat mass, and percentage fat mass (PFM). The within-family quantitative transmission disequilibrium test, which is robust to sample stratification, was implemented to evaluate the association of TNFR2 gene with obesity phenotypes. Evidence of association was obtained at SNP9 (rs5746059) with fat mass (P = 0.0002), BMI (P = 0.002), and PFM (P = 0.0006). The contribution of this polymorphism to the variation of fat mass and PFM was 6.24 and 7.82%, respectively. Individuals carrying allele A at the SNP9 site had a 4.6% higher fat mass and a 2.5% increased PFM compared to noncarriers. The results remained significant even after correction for multiple testing. Evidence of association between the TNFR2 gene and obesity phenotypes are also found in 700 independent Chinese Han and 1,000 random Caucasians samples. The results suggest that the TNFR2 gene polymorphisms contribute to the variation of obesity phenotypes. PMID:18685868

Zhao, Lan-Juan; Xiong, Dong-Hai; Pan, Feng; Liu, Xiao-Gang; Recker, Robert R.; Deng, Hong-Wen

2014-01-01

83

EEG asymmetry: relationship to mood and risk for alcoholism in Mission Indian youth  

Microsoft Academic Search

Background: Left frontal electroencephalogram (EEG) alpha dominance has been hypothesized to be related to depressed mood as well as aversive motivation and emotion. However, few studies have prospectively evaluated electroencephalogram asymmetry during development in high-risk adolescents and children.Methods: EEG alpha asymmetry was investigated in 134 Mission Indian children who were between 7 and 13 years of age. The relationships between

Cindy L Ehlers; Tamara L Wall; Consuelo Garcia-Andrade; Evelyn Phillips

2001-01-01

84

Sleep EEG fingerprints reveal accelerated thalamocortical oscillatory dynamics in Williams syndrome.  

PubMed

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 antero-posterior 8-16 Hz non-rapid-eye-movement (NREM) sleep EEG power distributions. Participants in Study I were 9 WS and 9 typically developing (TD) controls matched for age (14-29 years) and sex, and sleeping for two consecutive nights in the laboratory. WS participants were characterized by region-independent decreases in 10.50-12.50 Hz and central increases in 14.75-15.75 Hz EEG power. Region-independent decreases and increases in z-scores of the spectra were observed in the 10.25-12.25 Hz and 14-16 Hz ranges, respectively. Moreover, in the EEG spectra of participants with WS a lower probability for the emergence of a frontally dominant peak was observed. Parietal fast sigma peaks and the antero-posterior shifts in power distributions were of higher frequencies in WS (~1 Hz difference). A 1 year follow-up of 9 WS and 3 TD participants, as well as their inclusion into larger samples (20 WS and 20 TD, age: 6-29 years) of a two-night ambulatory home polysomnography study confirmed the WS-specific decrease in alpha/low sigma power (8-11.75 Hz) and the pattern of z-score differences (decreases: 8.50-11.25 Hz; increases: 13.5-14 Hz), including the antero-posterior shifts in power distribution (0.5 Hz) and some features of the spectral peaks. Altogether these data suggest a decrease in alpha/low sigma power, as well as a redistribution of NREM sleep 8-16 Hz EEG power toward the higher frequencies and/or a higher frequency of NREM sleep thalamocortical oscillations in WS. PMID:22093660

Bódizs, Róbert; Gombos, Ferenc; Kovács, Ilona

2012-01-01

85

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

PubMed Central

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 applied to specific lines of developmental research are also discussed. These examples include recent work on the infant mu rhythm and action processing, frontal alpha asymmetry and approach-withdrawal tendencies, and EEG power measures in the study of early psychosocial adversity. PMID:22545661

Saby, Joni N.; Marshall, Peter J.

2012-01-01

86

Automatic adaptive segmentation of clinical EEGs.  

PubMed

A method of automatic adaptive segmentation of EEGs, whereby the boundaries between different patterns of activity appearing in a given channel are identified and demarcated, has been applied to a group of clinical EEGs. The EEGs were especially selected from a library of 70 recordings so as to include a diversity of normal and abnormal EEG patterns. In the subsequent steps of the analysis, like segments were automatically clustered and a dendrogram plotted, from which the principal clusters or types of activity were visually selected. For the latter, a temporal profile was then plotted, indicating which type of activity was present at any given time during the respective recording. Summary parameters of mean amplitude and a measure of mean frequency were plotted alongside the temporal profile. The findings are as follows. (1) A single set of segmentation parameters was found to be clinically satisfactory for the entire group. (2) The inappropriateness of adaptive segmentation for the isolation of spikes and sharp waves, which had been anticipated in view of the short duration of such transients in relation to the length of the window (1.2 sec) used for the autocorrelation functions employed in the segmentation algorithm, was confirmed. A separate spike/sharp-wave detection algorithm is therefore planned. (3) Longer transients (i.e., some 300 msec or greater) are segmented and separately clustered. (4) For an individual EEG, the number of clinically significant clusters was 5 or less. (5) If a given cluster included activity in more than one frequency band (for example, simultaneous alpha and slow activity) the simple summary parameters of mean amplitude and a measure of mean frequency may not be sufficient for a clinically adequate description; however, the original autocorrelation function, or, more conventionally, the power spectrum (which can be estimated from the autocorrelation function) provides the necessary information. (6) The use of automatic adaptive EEG segmentation minimized human bias in the selection of portions of EEG recordings for computer analysis. PMID:6165551

Barlow, J S; Creutzfeldt, O D; Michael, D; Houchin, J; Epelbaum, H

1981-05-01

87

Electroencephalogram (EEG) (For Parents)  

MedlinePLUS

... to identify causes of other problems such as sleep disorders and changes in behavior. EEGs are sometimes used to evaluate brain activity after a severe head injury or before heart or liver transplantation. Preparation If your child is having an EEG, preparation is minimal. Your ...

88

Modification of EEG power spectra and EEG connectivity in autobiographical memory: a sLORETA study.  

PubMed

The aim of the present study was to explore the modifications of scalp EEG power spectra and EEG connectivity during the autobiographical memory test (AM-T) and during the retrieval of an autobiographical event (the high school final examination, Task 2). Seventeen healthy volunteers were enrolled (9 women and 8 men, mean age 23.4 ± 2.8 years, range 19-30). EEG was recorded at baseline and while performing the autobiographical memory (AM) tasks, by means of 19 surface electrodes and a nasopharyngeal electrode. EEG analysis was conducted by means of the standardized LOw Resolution Electric Tomography (sLORETA) software. Power spectra and lagged EEG coherence were compared between EEG acquired during the memory tasks and baseline recording. The frequency bands considered were as follows: delta (0.5-4 Hz); theta (4.5-7.5 Hz); alpha (8-12.5 Hz); beta1 (13-17.5 Hz); beta2 (18-30 Hz); gamma (30.5-60 Hz). During AM-T, we observed a significant delta power increase in left frontal and midline cortices (T = 3.554; p < 0.05) and increased EEG connectivity in delta band in prefrontal, temporal, parietal, and occipital areas, and for gamma bands in the left temporo-parietal regions (T = 4.154; p < 0.05). In Task 2, we measured an increased power in the gamma band located in the left posterior midline areas (T = 3.960; p < 0.05) and a significant increase in delta band connectivity in the prefrontal, temporal, parietal, and occipital areas, and in the gamma band involving right temporo-parietal areas (T = 4.579; p < 0.05). These results indicate that AM retrieval engages in a complex network which is mediated by both low- (delta) and high-frequency (gamma) EEG bands. PMID:24610490

Imperatori, Claudio; Brunetti, Riccardo; Farina, Benedetto; Speranza, Anna Maria; Losurdo, Anna; Testani, Elisa; Contardi, Anna; Della Marca, Giacomo

2014-08-01

89

Seizures and EEG features in 74 patients with genetic-dysmorphic syndromes.  

PubMed

Epilepsy is one of the most common findings in chromosome aberrations. Types of seizures and severity may significantly vary both between different conditions and within the same aberration. Hitherto specific seizures and EEG patterns are identified for only few syndromes. We studied 74 patients with defined genetic-dysmorphic syndromes with and without epilepsy in order to assess clinical and electroencephalographic features, to compare our observation with already described electro-clinical phenotypes, and to identify putative electroencephalographic and/or seizure characteristics useful to address the diagnosis. In our population, 10 patients had chromosomal disorders, 19 microdeletion or microduplication syndromes, and 32 monogenic syndromes. In the remaining 13, syndrome diagnosis was assessed on clinical grounds. Our study confirmed the high incidence of epilepsy in genetic-dysmorphic syndromes. Moreover, febrile seizures and neonatal seizures had a higher incidence compared to general population. In addition, more than one third of epileptic patients had drug-resistant epilepsy. EEG study revealed poor background organization in 42 patients, an excess of diffuse rhythmic activities in beta, alpha or theta frequency bands in 34, and epileptiform patterns in 36. EEG was completely normal only in 20 patients. No specific electro-clinical pattern was identified, except for inv-dup15, Angelman, and Rett syndromes. Nevertheless some specific conditions are described in detail, because of notable differences from what previously reported. Regarding the diagnostic role of EEG, we found that-even without any epileptiform pattern-the generation of excessive rhythmic activities in different frequency bandwidths might support the diagnosis of a genetic syndrome. © 2014 Wiley Periodicals, Inc. PMID:25257908

Alfei, Enrico; Raviglione, Federico; Franceschetti, Silvana; D'Arrigo, Stefano; Milani, Donatella; Selicorni, Angelo; Riva, Daria; Zuffardi, Orsetta; Pantaleoni, Chiara; Binelli, Simona

2014-12-01

90

Motivational mechanisms (BAS) and prefrontal cortical activation contribute to recognition memory for emotional words. rTMS effect on performance and EEG (alpha band) measures.  

PubMed

The present research addressed the question of where memories for emotional words could be represented in the brain. A second main question was related to the effect of personality traits, in terms of the Behavior Activation System (BAS), in emotional word recognition. We tested the role of the left DLPFC (LDLPFC) by performing a memory task in which old (previously encoded targets) and new (previously not encoded distractors) positive or negative emotional words had to be recognized. High-BAS and low-BAS subjects were compared when a repetitive TMS (rTMS) was applied on the LDLPFC. We found significant differences between high-BAS vs. low-BAS subjects, with better performance for high-BAS in response to positive words. In parallel, an increased left cortical activity (alpha desynchronization) was observed for high-BAS in the case of positive words. Thus, we can conclude that the left approach-related hemisphere, underlying BAS, may support faster recognition of positive words. PMID:25190327

Balconi, Michela; Cobelli, Chiara

2014-10-01

91

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

92

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

2012-01-01

93

Identifying periods of drowsy driving using EEG.  

PubMed

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

Brown, Timothy; Johnson, Robin; Milavetz, Gary

2013-01-01

94

Identifying Periods of Drowsy Driving Using EEG  

PubMed Central

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

Brown, Timothy; Johnson, Robin; Milavetz, Gary

2013-01-01

95

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

PubMed Central

Rising life expectancies coupled with an increasing awareness of age-related cognitive decline have led to the unwarranted use of psychopharmaceuticals, including acetylcholinesterase inhibitors (AChEIs), by significant numbers of healthy older individuals. This trend has developed despite very limited data regarding the effectiveness of such drugs on non-clinical groups and recent work indicates that AChEIs can have negative cognitive effects in healthy populations. For the first time, we use a combination of EEG and simultaneous EEG/fMRI to examine the effects of a commonly prescribed AChEI (donepezil) on cognition in healthy older participants. The short- and long-term impact of donepezil was assessed using two double-blind, placebo-controlled trials. In both cases, we utilised cognitive (paired associates learning (CPAL)) and electrophysiological measures (resting EEG power) that have demonstrated high-sensitivity to age-related cognitive decline. Experiment 1 tested the effects of 5 mg/per day dosage on cognitive and EEG markers at 6-hour, 2-week and 4-week follow-ups. In experiment 2, the same markers were further scrutinised using simultaneous EEG/fMRI after a single 5 mg dose. Experiment 1 found significant negative effects of donepezil on CPAL and resting Alpha and Beta band power. Experiment 2 replicated these results and found additional drug-related increases in the Delta band. EEG/fMRI analyses revealed that these oscillatory differences were associated with activity differences in the left hippocampus (Delta), right frontal-parietal network (Alpha), and default-mode network (Beta). We demonstrate the utility of simple cognitive and EEG measures in evaluating drug responses after acute and chronic donepezil administration. The presentation of previously established markers of age-related cognitive decline indicates that AChEIs can impair cognitive function in healthy older individuals. To our knowledge this is the first study to identify the precise neuroanatomical origins of EEG drug markers using simultaneous EEG/fMRI. The results of this study may be useful for evaluating novel drugs for cognitive enhancement. PMID:21931653

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

2011-01-01

96

EEG and Autism Diagnosis  

MedlinePLUS Videos and Cool Tools

... hand corner of the player. EEG and Autism Diagnosis HealthDay September 24, 2014 Related MedlinePlus Page Autism ... 1 in 68 children has autism spectrum disorder. Diagnosis is currently based on behavioral characteristics and symptoms. ...

97

EEG recovery enhanced by acute aerobic exercise after performing mental task with listening to unpleasant sound  

Microsoft Academic Search

The present paper investigated response of electroencephalogram (EEG) to aerobic exercise with low intensity after performing mental task with listening to acoustic stimuli in order to measure a recovery effect of the acute exercise on the EEG. The mean amplitude of the alpha wave (8–13 Hz) was significantly reduced during performing mental arithmetic and\\/or listening to 5 KHz unpleasant tone.

Seiji Nishifuji

2011-01-01

98

From EEG to BOLD: brain mapping and estimating transfer functions in simultaneous EEG-fMRI acquisitions.  

PubMed

Simultaneous acquisition of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) aims to disentangle the description of brain processes by exploiting the advantages of each technique. Most studies in this field focus on exploring the relationships between fMRI signals and the power spectrum at some specific frequency bands (alpha, beta, etc.). On the other hand, brain mapping of EEG signals (e.g., interictal spikes in epileptic patients) usually assumes an haemodynamic response function for a parametric analysis applying the GLM, as a rough approximation. The integration of the information provided by the high spatial resolution of MR images and the high temporal resolution of EEG may be improved by referencing them by transfer functions, which allows the identification of neural driven areas without strong assumptions about haemodynamic response shapes or brain haemodynamic's homogeneity. The difference on sampling rate is the first obstacle for a full integration of EEG and fMRI information. Moreover, a parametric specification of a function representing the commonalities of both signals is not established. In this study, we introduce a new data-driven method for estimating the transfer function from EEG signal to fMRI signal at EEG sampling rate. This approach avoids EEG subsampling to fMRI time resolution and naturally provides a test for EEG predictive power over BOLD signal fluctuations, in a well-established statistical framework. We illustrate this concept in resting state (eyes closed) and visual simultaneous fMRI-EEG experiments. The results point out that it is possible to predict the BOLD fluctuations in occipital cortex by using EEG measurements. PMID:20116435

Sato, João R; Rondinoni, Carlo; Sturzbecher, Marcio; de Araujo, Draulio B; Amaro, Edson

2010-05-01

99

EEG source imaging during two Qigong meditations.  

PubMed

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

2012-08-01

100

Correlates of alpha rhythm in functional magnetic resonance imaging and near infrared spectroscopy  

Microsoft Academic Search

We used simultaneous electroencephalogram-functional magnetic resonance imaging (EEG-fMRI) and EEG-near infrared spectroscopy (NIRS) to investigate whether changes of the posterior EEG alpha rhythm are correlated with changes in local cerebral blood oxygenation. Cross-correlation analysis of slowly fluctuating, spontaneous rhythms in the EEG and the fMRI signal revealed an inverse relationship between alpha activity and the fMRI-blood oxygen level dependent signal

Matthias Moosmann; Petra Ritter; Ina Krastel; Andrea Brink; Sebastian Thees; Felix Blankenburg; Birol Taskin; Hellmuth Obrig; Arno Villringer

2003-01-01

101

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

PubMed

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

2013-09-01

102

Response of Hepatitis C Virus to Long-Term Passage in the Presence of Alpha Interferon: Multiple Mutations and a Common Phenotype  

PubMed Central

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

2013-01-01

103

EEG patterns in persons exposed to ionizing radiation as a result of the Chernobyl accident: part 1: conventional EEG analysis.  

PubMed

Prospective conventional EEG study was carried out 3-5 and 10-13 years after the Chernobyl accident (1986) in patients who had acute radiation sickness and in emergency workers in 1986 ("liquidators"). Control groups comprised healthy volunteers; veterans of the Afghanistan war with posttraumatic stress disorder; veterans with mild traumatic brain injury; and patients with dyscirculatory encephalopathy. In 3-5 years after irradiation, there were irritated EEG changes with paroxysmal activity shifted to the left frontotemporal region (cortical-limbic overactivation) that were transformed 10-13 years after irradiation toward a low-voltage EEG pattern with excess of fast (beta) and slow (delta) activity together with depression of alpha and theta activity (organic brain damage with inhibition of the cortical-limbic system). Quantitative EEG is likely to be very informative for investigation of dose-effect relationships. PMID:11748314

Loganovsky, K N; Yuryev, K L

2001-01-01

104

Interindividual Differences in Alpha and Theta Power Reflect Memory Performance.  

ERIC Educational Resources Information Center

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

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

1999-01-01

105

A time variation of professional driver's EEG in monotonous work  

Microsoft Academic Search

An experiment was conducted on five subjects to determine the time it takes for slow alpha wave activity to appear during monotonous tasks. The experiment measured the time of response to digits appearing on a screen and the time of appearance of slow waves in the electroencephalograms (EEGs). Two professional automobile drivers were tested, as well as one maintenance technician

K. Idogawa; S. P. Ninomija; F. Yano

1989-01-01

106

Flexible electroencephalogram (EEG) headband  

NASA Technical Reports Server (NTRS)

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

Raggio, L. J.

1973-01-01

107

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.

2009-01-01

108

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

PubMed

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

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

2010-01-15

109

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)

2009-02-01

110

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

PubMed Central

Electroencephalography (EEG) frequencies have been linked to specific functions as an “electrophysiological signature” of a function. A combination of oscillatory rhythms has also been described for specific functions, with or without predominance of one specific frequency-band. In a simultaneous fMRI-EEG study at 3 T we studied the relationship between the default mode network (DMN) and the power of EEG frequency bands. As a methodological approach, we applied Multivariate Exploratory Linear Optimized Decomposition into Independent Components (MELODIC) and dual regression analysis for fMRI resting state data. EEG power for the alpha, beta, delta and theta-bands were extracted from the structures forming the DMN in a region-of-interest approach by applying Low Resolution Electromagnetic Tomography (LORETA). A strong link between the spontaneous BOLD response of the left parahippocampal gyrus and the delta-band extracted from the anterior cingulate cortex was found. A positive correlation between the beta-1 frequency power extracted from the posterior cingulate cortex (PCC) and the spontaneous BOLD response of the right supplementary motor cortex was also established. The beta-2 frequency power extracted from the PCC and the precuneus showed a positive correlation with the BOLD response of the right frontal cortex. Our results support the notion of beta-band activity governing the “status quo” in cognitive and motor setup. The highly significant correlation found between the delta power within the DMN and the parahippocampal gyrus is in line with the association of delta frequencies with memory processes. We assumed “ongoing activity” during “resting state” in bringing events from the past to the mind, in which the parahippocampal gyrus is a relevant structure. Our data demonstrate that spontaneous BOLD fluctuations within the DMN are associated with different EEG-bands and strengthen the conclusion that this network is characterized by a specific electrophysiological signature created by combination of different brain rhythms subserving different putative functions. PMID:24505434

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

2014-01-01

111

Genetic variation of individual alpha frequency (IAF) and alpha power in a large adolescent twin sample  

Microsoft Academic Search

To further clarify the mode of genetic transmission on individual alpha frequency (IAF) and alpha power, the extent to which individual differences in these alpha indices are influenced by genetic factors were examined in a large sample of adolescent twins (237 MZ, 282 DZ pairs; aged 16). EEG was measured at rest (eyes closed) from the right occipital site, and

Christine M. Smit; Margaret J. Wright; Narelle K. Hansell; Gina M. Geffen; Nicholas G. Martin

2006-01-01

112

[EEG in mathematical logical problem solving].  

PubMed

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

2010-01-01

113

The EEG in Huntington's chorea: a clinical and neuropathological study  

PubMed Central

The EEGs are reported on a group of 95 patients with Huntington's chorea. Thirty one showed little activity of any kind, and in particular no alpha rhythm above 10 ?V in amplitude was seen. Only those records which still met these criteria when re-examined were included in the `low voltage' category. EEGs in this category occurred significantly more frequently in institutionalized patients and in those with a positive family history of Huntington's chorea, dementia, and choreiform movements together. Computer averaged responses to light and sound were found in the three patients examined, though their routine EEGs were low voltage. Neuropathological examination confirmed a clinical diagnosis of Huntington's chorea in 14 patients investigated. There was a statistically significant association between cortical atrophy, including the frontal lobe, and a `low voltage' EEG. It was concluded that the low voltage record, though not specific for Huntington's chorea, was rare in other neurological disorders. The EEG is therefore of value in patients suspected of having Huntington's chorea as well as in various presenile dementias. PMID:4260288

Scott, D. F.; Heathfield, K. W. G.; Toone, B.; Margerison, J. H.

1972-01-01

114

Spectral EEG Features of a Short Psycho-physiological Relaxation  

NASA Astrophysics Data System (ADS)

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

Teplan, Michal; Krakovská, Anna; Špajdel, Marián

2014-08-01

115

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

PubMed Central

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

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

2008-01-01

116

Simultaneous MEG and intracranial EEG recordings during attentive reading.  

PubMed

The relationship between neural oscillations recorded at various spatial scales remains poorly understood partly due to an overall dearth of studies utilizing simultaneous measurements. In an effort to study quantitative markers of attention during reading, we performed simultaneous magnetoencephalography (MEG) and intracranial electroencephalography (iEEG) recordings in four epileptic patients. Patients were asked to attend to a specific color when presented with an intermixed series of red words and green words, with words of a given color forming a cohesive story. We analyzed alpha, beta, and gamma band oscillatory responses to the word presentation and compared the strength and spatial organization of those responses in both electrophysiological recordings. Time-frequency analysis of iEEG revealed a network of clear attention-modulated high gamma band (50-150 Hz) power increases and alpha/beta (9-25 Hz) suppressions in response to the words. In addition to analyses at the sensor level, MEG time-frequency analysis was performed at the source level using a sliding window beamformer technique. Strong alpha/beta suppressions were observed in MEG reconstructions, in tandem with iEEG effects. While the MEG counterpart of high gamma band enhancement was difficult to interpret at the sensor level in two patients, MEG time-frequency source reconstruction revealed additional activation patterns in accordance with iEEG results. Importantly, iEEG allowed us to confirm that several sources of gamma band modulation observed with MEG were indeed of cortical origin rather than EMG muscular or ocular artifact. PMID:19349241

Dalal, Sarang S; Baillet, Sylvain; Adam, Claude; Ducorps, Antoine; Schwartz, Denis; Jerbi, Karim; Bertrand, Olivier; Garnero, Line; Martinerie, Jacques; Lachaux, Jean-Philippe

2009-05-01

117

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

PubMed

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

Berkovich-Ohana, Aviva; Glicksohn, Joseph; Goldstein, Abraham

2014-10-01

118

Dry EEG Electrodes  

PubMed Central

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

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

2014-01-01

119

Postictal generalized EEG suppression  

PubMed Central

Objective: To determine the consistency and facilitating cofactors of postictal generalized EEG suppression (PGES) of >20 seconds after convulsive seizures (CS), a suggested predictor of sudden unexpected death in epilepsy risk. Methods: We retrospectively reviewed video-EEG data of people with ?2 recorded CS. Presence and duration of PGES were assessed by 2 independent observers blinded to patient status. Intraindividual consistency of PGES >20 seconds was determined and correlations with clinical characteristics were analyzed after correction for individual effects and the varying number of seizures. Results: One hundred fifty-four seizures in 59 people were analyzed. PGES >20 seconds was found in 37 individuals (63%) and 57 (37%) of CS. The proportion of persons in whom PGES occurred consistently (presence or absence of PGES >20 seconds in all CS) was lower in those with more CS. PGES of >20 seconds was more frequent in seizures arising from sleep (odds ratio 3.29, 95% confidence interval 1.21–8.96) and when antiepileptic medication was tapered (odds ratio 4.80, 95% confidence interval 1.27–18.14). Conclusion: Apparent PGES consistency was less frequent in people with more CS recorded, suggesting that PGES is an inconsistent finding in any one individual. Thus, we believe that PGES >20 seconds is not a reliable predictor of sudden unexpected death in epilepsy. Sleep and antiepileptic drug reduction appear to facilitate the occurrence of PGES. PMID:23966251

Lamberts, Robert J.; Gaitatzis, Athanasios; Sander, Josemir W.; Elger, Christian E.

2013-01-01

120

The functional Val158Met polymorphism of COMT predicts interindividual differences in brain alpha oscillations in young men.  

PubMed

Individual patterns of the electroencephalogram (EEG) in wakefulness and sleep are among the most heritable traits in humans, yet distinct genetic and neurochemical mechanisms underlying EEG phenotypes are largely unknown. A functional polymorphism in the gene encoding catechol-O-methyltransferase (COMT), an enzyme playing an important role in cortical dopamine metabolism, causes a common substitution of methionine (Met) for valine (Val) at codon 158 of COMT protein. Val allele homozygotes exhibit higher COMT activity and lower dopaminergic signaling in prefrontal cortex than Met/Met homozygotes. Evidence suggests that this polymorphism affects executive functions in healthy individuals. We hypothesized that it also modulates functional aspects of EEG in wakefulness and sleep. EEG recordings were conducted twice on separate occasions in 10 Val/Val and 12 Met/Met allele carriers (all men) in wakefulness, and in baseline and recovery sleep before and after 40 h prolonged waking. During sleep deprivation, subjects received placebo and modafinil in randomized, cross-over manner. We show that the Val158Met polymorphism predicts stable and frequency-specific, interindividual variation in brain alpha oscillations. Alpha peak frequency in wakefulness was 1.4 Hz slower in Val/Val genotype than in Met/Met genotype. Moreover, Val/Val allele carriers exhibited less 11-13 Hz activity than Met/Met homozygotes in wakefulness, rapid-eye-movement (REM) sleep, and non-REM sleep. This difference was resistant against the effects of sleep deprivation and modafinil. The data demonstrate that mechanisms involving COMT contribute to interindividual differences in brain alpha oscillations, which are functionally related to executive performance such as counting tendency on a random number generation task in young adults. PMID:19726643

Bodenmann, Sereina; Rusterholz, Thomas; Dürr, Roland; Stoll, Claudia; Bachmann, Valérie; Geissler, Eva; Jaggi-Schwarz, Karin; Landolt, Hans-Peter

2009-09-01

121

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

Code of Federal Regulations, 2010 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...

2010-04-01

122

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

Code of Federal Regulations, 2011 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...

2011-04-01

123

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...

2013-04-01

124

21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.  

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

2014-04-01

125

21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

126

21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

127

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...

2010-04-01

128

Transverse patterning dissociates human EEG theta power and hippocampal BOLD activation  

PubMed Central

Theta oscillations (4-8 Hz) are often modulated in human electroencephalogram (EEG) studies of memory, whereas overlapping frequencies dominate rodent hippocampal EEG. An emerging parallelism between theta reactivity and hippocampal functional magnetic resonance imaging activation has suggested a homology between theta activity in humans and rodents, representing a process of cortico-hippocampal interaction involved in memory. In the present study, we investigated EEG reactivity during performance of a relational memory task that induces a negative hippocampal blood oxygenation level dependent (BOLD) signal change, compared to a nonrelational control condition. Relational trials induced theta increases and alpha decreases. Low Resolution Electromagnetic Brain Tomography estimates localized theta and alpha modulation to frontal midline and parietal midline cortices, respectively, both of which exhibit negative BOLD responses in this task. Thus, theta and alpha dynamics are dissociable from positive BOLD activation, and may, in fact, colocalize with negative BOLD responses. PMID:18823411

MELTZER, JED A.; FONZO, GREG A.; CONSTABLE, R. TODD

2009-01-01

129

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

1985-01-01

130

[The use of individual EEG peculiarities for increase of neurofeedback efficiency].  

PubMed

An aim of the study was to demonstrate efficiency of neurofeedback in using individual frequency ranges of electroencephalogram (EEG). The sessions of theta/beta decreasing and alpha simulating trainings were carried out in 2 outpatients: one of them with attention deficit disorder (a schoolboy) and another one with functional pain contraction (a professional musician). The neurofeedback with standard frequency did not result in any improvement of psychometric and EEG characteristics of both patients. The neurofeedback training with individual frequency of maximal peak and alpha band width improved these characteristics that suggest efficiency of the approach used. PMID:16548372

Bazanova, O M; Aftanas, L I

2006-01-01

131

HIF-1 alpha-induced up-regulation of miR-9 contributes to phenotypic modulation in pulmonary artery smooth muscle cells during hypoxia.  

PubMed

Pulmonary artery smooth muscle cells (PASMCs) are associated with the development of hypoxic pulmonary hypertension (HPH). Recent studies have implicated a critical role for microRNAs (miRNAs) in HPH; however, their expression and regulation in hypoxia-mediated phenotypic modulation of PASMCs remains largely unclear. Here, we report that miR-9 was induced in hypoxia and involved in a hypoxia-induced phenotypic switch in rat primary PASMCs. Knockdown of miR-9 followed by hypoxia exposure attenuated PASMCs proliferation and enhanced the expression of contractile genes in vascular smooth muscle cells (VSMCs), while overexpression of miR-9 in normoxia promoted a proliferative phenotype in PASMCs. The primary transcripts of miR-9-1 and miR-9-3, but not miR-9-2, increased dramatically after hypoxia, whereas silencing of the hypoxia-associated transcription factor HIF-1? following hypoxia exposure abolished the enhancement of both primary transcripts in PASMCs. Using in silico analysis, we found three putative HIF-1? binding motifs on miR-9-1 and one motif on miR-9-3 located within the 5-kb region upstream of the transcriptional start sites. Chromatin immunoprecipitation assay revealed that hypoxia enhanced the direct interaction between HIF-1? and the regulatory elements of miR-9-1 and miR-9-3. Reporter assays showed that the regulatory regions of miR-9-1 and miR-9-3 behaved as enhancers in a HIF-1?-dependent manner during hypoxia. Taken together, our data uncover a regulatory mechanism involving HIF-1?-mediated up-regulation of miR-9, which plays a role in the hypoxia-induced phenotypic switch of PASMCs. PMID:24615545

Shan, Fabo; Li, Junxia; Huang, Qing-Yuan

2014-10-01

132

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

PubMed

The most common mutations in type I collagen causing types II-IV osteogenesis imperfecta (OI) result in substitution for glycine in a Gly-Xaa-Yaa triplet by another amino acid. We delineated a Y-position substitution in a small pedigree with a combined OI/Ehlers-Danlos Syndrome (EDS) phenotype, characterized by moderately decreased DEXA z-score (-1.3 to -2.6), long bone fractures, and large-joint hyperextensibility. Affected individuals have an alpha1(I)R888C (p.R1066C) substitution in one COL1A1 allele. Polyacrylamide gel electrophoresis (PAGE) of [(3)H]-proline labeled steady-state collagen reveals slight overmodification of the alpha1(I) monomer band, much less than expected for a substitution of a neighboring glycine residue, and a faint alpha1(I) dimer. Dimers form in about 10% of proband type I collagen. Dimer formation is inefficient compared to a possible 25%, probably because the SH-side chains have less proximity in this Y-position than when substituting for a glycine. Theoretical stability calculations, differential scanning calorimetry (DSC) thermograms, and thermal denaturation curves showed only weak local destabilization from the Y-position substitution in one or two chains of a collagen helix, but greater destabilization is seen in collagen containing dimers. Y-position collagen dimers cause kinking of the helix, resulting in a register shift that is propagated the full length of the helix and causes resistance to procollagen processing by N-proteinase. Collagen containing the Y-position substitution is incorporated into matrix deposited in culture, including immaturely and maturely cross-linked fractions. In vivo, proband dermal fibrils have decreased density and increased diameter compared to controls, with occasional aggregate formation. This report on Y-position substitutions in type I collagen extends the range of phenotypes caused by nonglycine substitutions and shows that, similar to X- and Y-position substitutions in types II and III collagen, the phenotypes resulting from nonglycine substitutions in type I collagen are distinct from those caused by glycine substitutions. PMID:17206620

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

2007-04-01

133

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

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

134

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

135

Relative power and coherence of EEG series are related to amnestic mild cognitive impairment in diabetes  

PubMed Central

Objective: Diabetes is a risk factor for dementia and mild cognitive impairment. The aim of this study was to investigate whether some features of resting-state EEG (rsEEG) could be applied as a biomarker to distinguish the subjects with amnestic mild cognitive impairment (aMCI) from normal cognitive function in type 2 diabetes. Materials and Methods: In this study, 28 patients with type 2 diabetes (16 aMCI patients and 12 controls) were investigated. Recording of the rsEEG series and neuropsychological assessments were performed. The rsEEG signal was first decomposed into delta, theta, alpha, beta, gamma frequency bands. The relative power of each given band/sum of power and the coherence of waves from different brain areas were calculated. The extracted features from rsEEG and neuropsychological assessments were analyzed as well. Results: The main findings of this study were that: (1) compared with the control group, the ratios of power in theta band [P(theta)] vs. power in alpha band [P(alpha)] [P(theta)/P(alpha)] in the frontal region and left temporal region were significantly higher for aMCI, and (2) for aMCI, the alpha coherences in posterior, fronto-right temporal, fronto-posterior, right temporo-posterior were decreased; the theta coherences in left central-right central (LC-RC) and left posterior-right posterior (LP-RP) regions were also decreased; but the delta coherences in left temporal-right temporal (LT-RT) region were increased. Conclusion: The proposed indexes from rsEEG recordings could be employed to track cognitive function of diabetic patients and also to help in the diagnosis of those who develop aMCI. PMID:24550827

Bian, Zhijie; Li, Qiuli; Wang, Lei; Lu, Chengbiao; Yin, Shimin; Li, Xiaoli

2014-01-01

136

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

1999-01-01

137

[Dynamics of EEG-indicators in alcohol abstinence].  

PubMed

To study the possibility of discrimination of different periods of alcohol abstinence state (acute, subacute, and arrested) the brain electrical activity of 30 patients with chronic alcoholism was recorded from 24 sites of convexital scalp surface during the detoxication. The "Synchro-EEG" program package was applied for EEG processing using 840 parameters. Sets of state-specific characters were selected, and an integral parameter for estimation of the brain functional state was developed. Parameters of coherence of biopotentials in narrow frequency subbands turned to be of the greatest informative value. As compared to the normal state, in the acute period all the frequency components were changed. Their dynamics during detoxication was different. Delta and theta activity were normalized faster then the alpha and beta frequencies. The dynamics of the spatial synchronization foci reflected the recovery of consciousness and normalization of the brain functional state. PMID:12013651

Sviderskaia, N E; Glazkova, V A; Agaronov, V R; Abolmasova, O B

2002-01-01

138

Behavioural phenotypes  

Microsoft Academic Search

Behavioural phenotypes are specific psychological characteristics with a known genetic aetiology. Like their somatic counterparts, the identification of behavioural phenotypes is potentially of clinical value. Various genetic mechanisms are associated with characteristic cognitive and behavioural profiles. These include: normal functional variations (polymorphisms); genetic mutations (with associated loss of function); structural anomalies and chromosomal deletions. Most descriptions of behavioural phenotypes concern

Kate Lawrence

2005-01-01

139

Effects of a Psychedelic, Tropical Tea, Ayahuasca, on the Electroencephalographic (EEG) Activity of the Human Brain During a Shamanistic Ritual  

Microsoft Academic Search

EEG data from 12 volunteers participating in a workshop in Brazil were recorded under field conditions before and after a shamanistic ritual in which the psychoactive tea, ayahuasca, was consumed. Following three doses of the tea, the subjects showed strong and statistically significant increases of both EEG alpha (8-13Hz) and theta (4-8Hz) mean amplitudes compared to baseline while beta (13-20Hz)

Jan M. Keppel Hesselink; M. da Silveira Barbosa

2001-01-01

140

Quantitative EEG analysis at rest and during photic stimulation in drug-naive patients with first-episode paranoid schizophrenia  

Microsoft Academic Search

In the present study, quantitative EEG analysis was performed at rest and during 10 Hz photic stimulation in 14 drug-naive patients with first-episode paranoid schizophrenia and 20 sex- and age-matched control subjects. Compared with the normal controls, the patients had significantly lower alpha-2 band amplitude in the resting EEG over all recording regions. No significant group differences were found in

Yuji Wada; Yuko Takizawa; Saeko Kitazawa; Jiang Zheng-Yan; Nariyoshi Yamaguchi

1994-01-01

141

TNFalpha up-regulates SLUG via the NF-kappaB/HIF1alpha axis, which imparts breast cancer cells with a stem cell-like phenotype.  

PubMed

Extracellular and intracellular mediators of inflammation, such as tumor necrosis factor alpha (TNF?) and NF-kappaB (NF-?B), play major roles in breast cancer pathogenesis, progression and relapse. SLUG, a mediator of the epithelial-mesenchymal transition process, is over-expressed in CD44(+)/CD24(-) tumor initiating breast cancer cells and in basal-like carcinoma, a subtype of aggressive breast cancer endowed with a stem cell-like gene expression profile. Cancer stem cells also over-express members of the pro-inflammatory NF-?B network, but their functional relationship with SLUG expression in breast cancer cells remains unclear. Here, we show that TNF? treatment of human breast cancer cells up-regulates SLUG with a dependency on canonical NF-?B/HIF1? signaling, which is strongly enhanced by p53 inactivation. Moreover, SLUG up-regulation engenders breast cancer cells with stem cell-like properties including enhanced expression of CD44 and Jagged-1 in conjunction with estrogen receptor alpha down-regulation, growth as mammospheres, and extracellular matrix invasiveness. Our results reveal a molecular mechanism whereby TNF?, a major pro-inflammatory cytokine, imparts breast cancer cells with stem cell-like features, which are connected to increased tumor aggressiveness. PMID:20509143

Storci, Gianluca; Sansone, Pasquale; Mari, Sara; D'Uva, Gabriele; Tavolari, Simona; Guarnieri, Tiziana; Taffurelli, Mario; Ceccarelli, Claudio; Santini, Donatella; Chieco, Pasquale; Marcu, Kenneth B; Bonafè, Massimiliano

2010-11-01

142

Responses to tonic heat pain in the ongoing EEG under conditions of controlled attention.  

PubMed

To confirm the existence of an ongoing electroencephalogram (EEG) pattern that is truly suggestive of pain, tonic heat pain was induced by small heat pulses at 1 °C above the pain threshold and compared to slightly less intense tonic non-painful heat pulses at 1 °C below the pain threshold. Twenty healthy subjects rated the sensation intensity during thermal stimulation. Possible confounding effects of attention were thoroughly controlled for by testing in four conditions: (1) focus of attention directed ipsilateral or (2) contralateral to the side of the stimulation, (3) control without a side preference, and (4) no control of attention at all. EEG was recorded via eight leads according to the 10/20 convention. Absolute power was computed for the frequency bands delta (0.5-4 Hz), theta (4-8 Hz), alpha1 (8-11 Hz), alpha2 (11-14 Hz), beta1 (14-25 Hz), and beta2 (25-35 Hz). Ratings were clearly distinct between the heat and pain conditions and suggestive for heat and pain sensations. Manipulation of attention proved to be successful by producing effects on the ratings and on the EEG activity (with lower ratings and lower EEG activity (theta, beta1, 2) over central areas for side-focused attention). During pain stimulation, lower central alpha1 and alpha2 activity and higher right-parietal and right-occipital delta power were observed compared to heat stimulation. This EEG pattern was not influenced by the manipulation of attention. Since the two types of stimuli (pain, heat) were subjectively felt differently although stimulation intensities were nearby, we conclude that this EEG pattern is clearly suggestive of pain. PMID:24320554

Giehl, Janet; Meyer-Brandis, Gesa; Kunz, Miriam; Lautenbacher, Stefan

2014-03-01

143

Application of independent component analysis for the data mining of simultaneous Eeg-fMRI: preliminary experience on sleep onset.  

PubMed

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 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. PMID:19922343

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

2009-01-01

144

Levels of Alpha-Toxin Correlate with Distinct Phenotypic Response Profiles of Blood Mononuclear Cells and with agr Background of Community-Associated Staphylococcus aureus Isolates  

PubMed Central

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

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

2014-01-01

145

Effect of independent component analysis on multifractality of EEG during visual-motor task  

Microsoft Academic Search

In visual-motor task, blinks, muscle and other short-term artifacts may corrupt the correct determination of the fractal properties of the brain signals that reflect task performance. We tested whether independent component analysis (ICA) is a necessary preprocessing tool to determine fractal properties of amplitudes of decomposed EEG records in theta, alpha, beta and gamma oscillations. The subjects were required to

D. Popivanov; S. Jivkova; V. Stomonyakov; G. Nicolova

2005-01-01

146

Evaluation of EEG Features in Decoding Individual Finger Movements from One Hand  

PubMed Central

With the advancements in modern signal processing techniques, the field of brain-computer interface (BCI) is progressing fast towards noninvasiveness. One challenge still impeding these developments is the limited number of features, especially movement-related features, available to generate control signals for noninvasive BCIs. A few recent studies investigated several movement-related features, such as spectral features in electrocorticography (ECoG) data obtained through a spectral principal component analysis (PCA) and direct use of EEG temporal data, and demonstrated the decoding of individual fingers. The present paper evaluated multiple movement-related features under the same task, that is, discriminating individual fingers from one hand using noninvasive EEG. The present results demonstrate the existence of a broadband feature in EEG to discriminate individual fingers, which has only been identified previously in ECoG. It further shows that multiple spectral features obtained from the spectral PCA yield an average decoding accuracy of 45.2%, which is significantly higher than the guess level (P < 0.05) and other features investigated (P < 0.05), including EEG spectral power changes in alpha and beta bands and EEG temporal data. The decoding of individual fingers using noninvasive EEG is promising to improve number of features for control, which can facilitate the development of noninvasive BCI applications with rich complexity. PMID:23710250

2013-01-01

147

Use of EEG to track visual attention in two dimensions  

NASA Astrophysics Data System (ADS)

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

Coleman, Robert Alan

148

TNFalpha up-regulates SLUG via the NF-kappaB/HIF1alpha axis, which imparts breast cancer cells with a stem cell-like phenotype  

PubMed Central

Extracellular and intracellular mediators of inflammation, such as Tumor Necrosis Factor alpha (TNF?) and NF-kappaB (NF-?B), play major roles in breast cancer pathogenesis, progression and relapse. SLUG, a mediator of the epithelial-mesenchymal transition process, is over-expressed in CD44+/CD24? tumor initiating breast cancer cells and in basal-like carcinoma, a subtype of aggressive breast cancer endowed with a stem cell-like gene expression profile. Cancer stem cells also over-express members of the pro-inflammatory NF-?B network, but their functional relationship with SLUG expression in breast cancer cells remains unclear. Here, we show that TNF? treatment of human breast cancer cells up-regulates SLUG with a dependency on canonical NF-?B/HIF1? signaling, which is strongly enhanced by p53 inactivation. Moreover, SLUG up-regulation engenders breast cancer cells with stem cell-like properties including enhanced expression of CD44 and Jagged-1 in conjunction with ER? down-regulation, growth as mammospheres and extracellular matrix invasiveness. Our results reveal a molecular mechanism whereby TNF?, a major pro-inflammatory cytokine, imparts breast cancer cells with stem cell-like features, which are connected to increased tumor aggressiveness. PMID:20509143

Storci, Gianluca; Sansone, Pasquale; Mari, Sara; D'Uva, Gabriele; Tavolari, Simona; Guarnieri, Tiziana; Taffurelli, Mario; Ceccarelli, Claudio; Santini, Donatella; Chieco, Pasquale; Marcu, Kenneth B.; Bonafe, Massimiliano

2010-01-01

149

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

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

150

Unique phenotype and distinct TCR V beta repertoire in human peripheral blood alpha beta TCR+, CD4-, and CD8- double negative T cells.  

PubMed

TCR-alpha beta+ CD4- CD8- double-negative (DN) T cells represent a small, poorly defined T cell subset in human peripheral blood that has been postulated to be potentially autoreactive. To define some of the characteristics of this subset of T cells, DN cells and CD4+ and CD8+ single-positive (SP) cells were purified from the peripheral blood of six unrelated individuals by a combination of positive selection and depletion using mAb conjugated to immunomagnetic beads. Purified DN cells were found to be enriched in cells expressing HLA-DR and the NK cell marker, CD56, when compared to the SP population. Furthermore, in contrast to SP cells that express the adhesion marker CD44, DN cells were found to express very little, if any, CD44. When the V beta TCR repertoires of DN and SP (CD4+ and CD8+) cells, determined by quantitative (q) PCR, were compared all three populations were found to be considerably different. Furthermore, several V beta segments (V beta 11 and V beta 19) were consistently expressed at higher levels on DN cells than on SP cells. The TCR repertoires of both DN and SP cells were frequently characterized by dominance of one or more V beta segments that could in some instances be shown to be restricted to the CD45RO+ ("memory") population. However, differences in TCR repertoire between DN and SP cells were observed even when CD45RO+ cells were removed before qPCR analysis. These studies suggest that the TCR repertoires of DN and SP cells are determined by different selection mechanisms and that DN and SP cells are directed against different Ag. PMID:8301117

Niehues, T; Gulwani-Akolkar, B; Akolkar, P N; Tax, W; Silver, J

1994-02-01

151

[Adaptive method for EEG spectrum component decomposition].  

PubMed

A new computerized method for EEG rhythms extraction is proposed as a development of the idea of adjustable boundaries of frequency components that was put forward in previous investigations. Principle component analysis of the correlation matrix of EEG spectra with subsequent rotation of factor solutions was used for decomposition of a spectrum into physically meaningful spectral components. The method was tested on EEG of 14 healthy subjects recorded in 17 functional waking states. Fourteen independent spectral components in the spectral range from 0 to 100 Hz were extracted and their frequency boundaries were consistent with the current knowledge on frequency components of EEG oscillations. Main advantage of the described method is the adjustable estimation of EEG frequency oscillators taking into account characteristic properties of individual EEGs. Possible area of application might be the correct evaluation of spectral power of the EEG rhythms, EEG coherence and other spectral characteristics in clinical and experimental research, studies of the frequency characteristics of the EEG rhythms in different human functional states, changes in frequency characteristics of the EEG rhythms during maturation and in mental pathology. PMID:22690555

Novototski?-Vlasov, V Iu; Stroganova, T A; Kovalev, V P

2012-01-01

152

Effects of neural synchrony on surface EEG.  

PubMed

It has long been assumed that the surface electroencephalography (EEG) signal depends on both the amplitude and spatial synchronization of underlying neural activity, though isolating their respective contribution remains elusive. To address this, we made simultaneous surface EEG measurements along with intracortical recordings of local field potentials (LFPs) in the primary visual cortex of behaving nonhuman primates. We found that trial-by-trial fluctuations in EEG power could be explained by a linear combination of LFP power and interelectrode temporal synchrony. This effect was observed in both stimulus and stimulus-free conditions and was particularly strong in the gamma range (30-100 Hz). Subsequently, we used pharmacological manipulations to show that neural synchrony can produce a positively modulated EEG signal even when the LFP signal is negatively modulated. Taken together, our results demonstrate that neural synchrony can modulate EEG signals independently of amplitude changes in neural activity. This finding has strong implications for the interpretation of EEG in basic and clinical research, and helps reconcile EEG response discrepancies observed in different modalities (e.g., EEG vs. functional magnetic resonance imaging) and different spatial scales (e.g., EEG vs. intracranial EEG). PMID:23236202

Musall, Simon; von Pföstl, Veronika; Rauch, Alexander; Logothetis, Nikos K; Whittingstall, Kevin

2014-04-01

153

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.?? PMID:10084544

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

1999-01-01

154

Subtractive Fuzzy Classifier Based Driver Distraction Levels Classification Using EEG  

PubMed Central

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

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

2013-01-01

155

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

PubMed

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

2013-01-01

156

Hypercapnia is a Key Correlate of EEG Activation and Daytime Sleepiness in Hypercapnic Sleep Disordered Breathing Patients  

PubMed Central

Background: The key determinants of daytime drowsiness in sleep disordered breathing (SDB) are unclear. Hypercapnia has not been examined as a potential contributor due to the lack of reliable measurement during sleep. To overcome this limitation, we studied predominantly hypercapnic SDB patients to investigate the role of hypercapnia on EEG activation and daytime sleepiness. Methods: We measured overnight polysomnography (PSG), arterial blood gases, and Epworth Sleepiness Scale in 55 severe SDB patients with obesity hypoventilation syndrome or overlap syndrome (COPD+ obstructive sleep apnea) before and ?3 months after positive airway pressure (PAP) treatment. Quantitative EEG analyses were performed, and the Delta/ Alpha ratio was used as an indicator of EEG activation. Results: After the PAP treatment, these patients showed a significant decrease in their waking pCO2, daytime sleepiness, as well as all key breathing/oxygenation parameters during sleep. Overnight Delta/Alpha ratio of EEG was significantly reduced. There is a significant cross-correlation between a reduced wake pCO2, a faster (more activated) sleep EEG (reduced Delta/Alpha ratio) and reduced daytime sleepiness (all p < 0.05) with PAP treatment. Multiple regression analyses showed the degree of change in hypercapnia to be the only significant predictor for both ESS and Delta/ Alpha ratio. Conclusions: Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic SDB patients. The relationship between hypercapnia and sleepiness may be mediated by reduced neuro-electrical brain activity. Commentary: A commentary on this article appears in this issue on page 523. Citation: Wang D, Piper AJ, Yee BJ, Wong KK, Kim JW, D'Rozario A, Rowsell L, Dijk DJ, Grunstein RR. Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic sleep disordered breathing patients. J Clin Sleep Med 2014;10(5):517-522. PMID:24910553

Wang, David; Piper, Amanda J.; Yee, Brendon J.; Wong, Keith K.; Kim, Jong-Won; D'Rozario, Angela; Rowsell, Luke; Dijk, Derk-Jan; Grunstein, Ronald R.

2014-01-01

157

Visually evoked phase synchronization changes of alpha rhythm in migraine: Correlations with clinical features  

Microsoft Academic Search

ObjectiveThis study aimed to compute phase synchronization of the alpha band from a multichannel electroencephalogram (EEG) recorded under repetitive flash stimulation from migraine patients without aura. This allowed examination of ongoing EEG activity during visual stimulation in the pain-free phase of migraine.

Marina de Tommaso; Daniele Marinazzo; Marco Guido; Giuseppe Libro; Sebastiano Stramaglia; Luigi Nitti; Gianluca Lattanzi; Leonardo Angelini; Mario Pellicoro

2005-01-01

158

Use of EEG to diagnose ADHD.  

PubMed

Electroencephalography (EEG) has, historically, played a focal role in the assessment of neural function in children with attention deficit hyperactivity disorder (ADHD). We review here the most recent developments in the utility of EEG in the diagnosis of ADHD, with emphasis on the most commonly used and emerging EEG metrics and their reliability in diagnostic classification. Considering the clinical heterogeneity of ADHD and the complexity of information available from the EEG signals, we suggest that considerable benefits are to be gained from multivariate analyses and a focus towards understanding of the neural generators of EEG. We conclude that while EEG cannot currently be used as a diagnostic tool, vast developments in analytical and technological tools in its domain anticipate future progress in its utility in the clinical setting. PMID:25234074

Lenartowicz, Agatha; Loo, Sandra K

2014-11-01

159

On the Individuality of Sleep EEG Spectra  

PubMed Central

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

Lewandowski, Achim; Rosipal, Roman; Dorffner, Georg

2013-01-01

160

Automated Epilepsy Diagnosis Using Interictal Scalp EEG  

E-print Network

Approximately over 50 million people worldwide suffer from epilepsy. Traditional diagnosis of epilepsy relies on tedious visual screening by highly trained clinicians from lengthy EEG recording that contains the presence of seizure (ictal) activities. Nowadays, there are many automatic systems that can recognize seizure-related EEG signals to help the diagnosis. However, it is very costly and inconvenient to obtain long-term EEG data with seizure activities, especially in areas short of medical resources. We demonstrate in this paper that we can use the interictal scalp EEG data, which is much easier to collect than the ictal data, to automatically diagnose whether a person is epileptic. In our automated EEG recognition system, we extract three classes of features from the EEG data and build Probabilistic Neural Networks (PNNs) fed with these features. We optimize the feature extraction parameters and combine these PNNs through a voting mechanism. As a result, our system achieves an impressive 94.07% accuracy...

Bao, Forrest Sheng; Hu, Jing; Lie, Donald Y -C; Zhang, Yuanlin; Oommen, K J

2009-01-01

161

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

PubMed

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

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

2011-05-30

162

Ellen R. Grass Lecture: extraordinary EEG.  

PubMed

The electroencephalogram (EEG) is a unique measure of the electrical function of the brain. Cerebral sources of EEG potentials expressed by the human brain have been recorded on the surface of the scalp for almost 100 years. With the advances in digital technology, present day EEG has evolved to include specialized techniques that offer new capabilities never realized before. Refined intracranial recording techniques and multi-channel systems now permit access to regions of the brain that have previously been off limits to conventional EEG recording. Extraordinary biorhythms beyond 1 to 35 Hz that have been typically used in routine EEG are now exploring extreme bandwidths that may disclose epileptogenic regions and their yield causative networks involved in generating seizures. These spectral frequencies ranging from infraslow activity to high frequency oscillations have far reaching implications for people with uncontrolled seizures. Micro-EEG recordings are now shedding light on electrophysiological recordings of single columns of neuronal activity in clinical research expanding our understanding of epilepsy to the cellular level. Beyond the routine application of EEG analyzed for clinical use, special EEG techniques now provide a window to reveal detailed information about the seizure onset zone in patients with epilepsy, as well as advance our understanding of the functional processes of the brain itself. These breakthroughs will allow EEG-based treatment alternatives. PMID:24783746

Tatum, William O

2014-03-01

163

Kapalabhati--yogic cleansing exercise. II. EEG topography analysis.  

PubMed

Topography of brain electrical activity was studied in 11 advanced yoga practitioners during yogic high-frequency breathing kapalabhati (KB). Alpha activity was increased during the initial five min of KB. Theta activity mostly in the occipital region was increased during later stages of 15 min KB compared to the pre-exercise period. Beta 1 activity increased during the first 10 min of KB in occipital and to a lesser degree in parietal regions. Alpha and beta 1 activity decreased and theta activity was maintained on the level of the initial resting period after KB. The score of General Deactivation factor from Activation Deactivation Adjective Checklist was higher after KB exercise than before the exercise. The results suggest a relative increase of slower EEG frequencies and relaxation on a subjective level as the after effect of KB exercise. PMID:1818698

Stancák, A; Kuna, M; Srinivasan; Dostálek, C; Vishnudevananda, S

1991-01-01

164

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. PMID:23006616

2012-01-01

165

From Oscillatory Transcranial Current Stimulation to Scalp EEG Changes: A Biophysical and Physiological Modeling Study  

PubMed Central

Both biophysical and neurophysiological aspects need to be considered to assess the impact of electric fields induced by transcranial current stimulation (tCS) on the cerebral cortex and the subsequent effects occurring on scalp EEG. The objective of this work was to elaborate a global model allowing for the simulation of scalp EEG signals under tCS. In our integrated modeling approach, realistic meshes of the head tissues and of the stimulation electrodes were first built to map the generated electric field distribution on the cortical surface. Secondly, source activities at various cortical macro-regions were generated by means of a computational model of neuronal populations. The model parameters were adjusted so that populations generated an oscillating activity around 10 Hz resembling typical EEG alpha activity. In order to account for tCS effects and following current biophysical models, the calculated component of the electric field normal to the cortex was used to locally influence the activity of neuronal populations. Lastly, EEG under both spontaneous and tACS-stimulated (transcranial sinunoidal tCS from 4 to 16 Hz) brain activity was simulated at the level of scalp electrodes by solving the forward problem in the aforementioned realistic head model. Under the 10 Hz-tACS condition, a significant increase in alpha power occurred in simulated scalp EEG signals as compared to the no-stimulation condition. This increase involved most channels bilaterally, was more pronounced on posterior electrodes and was only significant for tACS frequencies from 8 to 12 Hz. The immediate effects of tACS in the model agreed with the post-tACS results previously reported in real subjects. Moreover, additional information was also brought by the model at other electrode positions or stimulation frequency. This suggests that our modeling approach can be used to compare, interpret and predict changes occurring on EEG with respect to parameters used in specific stimulation configurations. PMID:23468970

Merlet, Isabelle; Birot, Gwenael; Salvador, Ricardo; Molaee-Ardekani, Behnam; Mekonnen, Abeye; Soria-Frish, Aureli; Ruffini, Giulio; Miranda, Pedro C.; Wendling, Fabrice

2013-01-01

166

Alpha and beta band power changes in normal and dyslexic children  

Microsoft Academic Search

Objective: Previous research with healthy subjects suggests that the lower alpha band reflects attentional whereas the upper alpha band semantic processes. The aim of the present study was to investigate whether dyslexics show deficits in attentional control and\\/or semantic encoding.Method: The EEG was recorded while subjects were reading numbers, words and pseudowords and analyzed in a lower and upper alpha

W. Klimesch; M. Doppelmayr; H. Wimmer; W. Gruber; D. Rohm; J. Schwaiger; F. Hutzler

2001-01-01

167

Spontaneous alpha peak frequency predicts working memory performance across the age span  

Microsoft Academic Search

Working memory capacity has been consistently shown to decline with increasing age. Mechanisms underlying this decline are poorly understood. One index that has been found to predict performance on memory tests is alpha peak frequency, the peak of spectral alpha power of the EEG. Activity in the alpha band has been also associated with higher cognitive functions including attention and

C. Richard Clark; Melinda D. Veltmeyer; Rebecca J. Hamilton; Elena Simms; Robert Paul; Daniel Hermens; Evian Gordon

2004-01-01

168

Increase trend of correlation and phase synchrony of microwire iEEG before macroseizure onset.  

PubMed

Micro/macrowire intracranial EEG (iEEG) signals recorded from implanted micro/macroelectrodes in epileptic patients have received great attention and are considered to include much information of neuron activities in seizure transition compared to scalp EEG from cortical electrodes. Microelectrode is contacted more close to neurons than macroelectrode and it is more sensitive to neuron activity changes than macroelectrode. Microwire iEEG recordings are inevitably advantageous over macrowire iEEG recordings to reveal neuronal mechanisms contributing to the generation of seizures. In this study, we investigate the seizure generation from microwire iEEG recordings and discuss synchronization of microwire iEEGs in four frequency bands: alpha (1-30 Hz), gamma (30-80 Hz), ripple (80-250 Hz), and fast ripple (>250 Hz) via two measures: correlation and phase synchrony. We find that an increase trend of correlation or phase synchrony exists before the macroseizure onset mostly in gamma and ripple bands where the duration of the preictal states varied in different seizures ranging up to a few seconds (minutes). This finding is contrast to the well-known result that a decrease of synchronization in macro domains exists before the macroseizure onset. The finding demonstrates that it is only when the seizure has recruited enough surrounding brain tissue does the signal become strong enough to be observed on the clinical macroelectrode and as a result support the hypothesis of progressive coalescence of microseizure domains. The potential ramifications of such an early detection of microscale seizure activity may open a new window on treatment by making possible disruption of seizure activity before it becomes fully established. PMID:24624231

Hu, Sanqing; Chi, Jianfen; Zhang, Jianhai; Kong, Wanzeng; Cao, Yu; He, Bin

2014-04-01

169

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. PMID:21171750

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

2012-01-01

170

Human cortical EEG rhythms during long-term episodic memory task. A high-resolution EEG study of the HERA model.  

PubMed

Many recent neuroimaging studies of episodic memory have indicated an asymmetry in prefrontal involvement, with the left prefrontal cortex more involved than the right in encoding, the right more than the left in retrieval (hemispheric encoding and retrieval asymmetry, or HERA model). In this electroencephalographic (EEG) high-resolution study, we studied brain rhythmicity during a visual episodic memory (recognition) task. The theta (4-6 Hz), alpha (6-12 Hz) and gamma (28-48 Hz) oscillations were investigated during a visuospatial long-term episodic memory task including an encoding (ENC) and retrieval (RET) phases. During the ENC phase, 25 figures representing interiors of buildings ("indoor") were randomly intermingled with 25 figures representing landscapes ("landscapes"). Subject's response was given at left ("indoor") or right ("landscapes") mouse button. During the RET phase (1 h later), 25 figures representing previously presented "indoor" pictures ("tests") were randomly intermingled with 25 figures representing novel "indoor" ("distractors"). Again, a mouse response was required. Theta and alpha EEG results showed no change of frontal rhythmicity. In contrast, the HERA prediction of asymmetry was fitted only by EEG gamma responses, but only in the posterior parietal areas. The ENC phase was associated with gamma EEG oscillations over left parietal cortex. Afterward, the RET phase was associated with gamma EEG oscillations predominantly over right parietal cortex. The predicted HERA asymmetry was thus observed in an unexpected location. This discrepancy may be due to the differential sensitivity of neuroimaging methods to selected components of cognitive processing. The strict relation between gamma response and perception suggests that retrieval processes of long-term memory deeply impinged upon sensory representation of the stored material. PMID:15050581

Babiloni, Claudio; Babiloni, Fabio; Carducci, Filippo; Cappa, Stefano; Cincotti, Febo; Del Percio, Claudio; Miniussi, Carlo; Moretti, Davide Vito; Pasqualetti, Patrizio; Rossi, Simone; Sosta, Katiuscia; Rossini, Paolo Maria

2004-04-01

171

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

172

Soft textile electrodes for EEG monitoring  

Microsoft Academic Search

There is a need for long term monitoring of the brain during intensive care. This is e.g. the case for newborn babies that have been exposed to hypoxia during delivery. Electroencephalography (EEG) is the technique of choice. To get a clear and detailed view of the brain activity a large number of EEG electrodes should be used. Applying traditional electrodes

J. Lo?fhede; Fernando Seoane; Magnus Thordstein

2010-01-01

173

Estimating Alertness from the EEG Power Spectrum  

Microsoft Academic Search

In tasks requiring sustained attention, human alertness varies on a minute time scale. This can have seriousconsequences in occupations ranging from air traffic control to monitoring of nuclear power plants. Changesin the electroencephalographic (EEG) power spectrum accompany these fluctuations in the level of alertness,as assessed by measuring simultaneous changes in EEG and performance on an auditory monitoring task. Bycombining power

Tzyy-ping Jung; Scott Makeig; Magnus Stensmo; Terrence J. Sejnowski

1997-01-01

174

Relevance of EEG alpha and theta oscillations during task switching  

Microsoft Academic Search

In a task switching design, we investigated the question whether long-range theta coupling primarily reflects top–down control\\u000a processes. Switch and stay trials did not differ with respect to memory load or global working memory (WM) demands. The results\\u000a revealed significantly stronger theta coupling (in a range of 4–7 Hz) between prefrontal and posterior regions during switch\\u000a as compared to stay trials.

P. Sauseng; W. Klimesch; R. Freunberger; T. Pecherstorfer; S. Hanslmayr; M. Doppelmayr

2006-01-01

175

Multiscale Entropy Analysis of EEG for Assessment of Post-Cardiac Arrest Neurological Recovery Under Hypothermia in Rats  

Microsoft Academic Search

Neurological complications after cardiac arrest (CA) can be fatal. Although hypothermia has been shown to be beneficial, understanding the mechanism and establishing neurological outcomes remains challenging because effects of CA and hypothermia are not well characterized. This paper aims to analyze EEG (and the alpha-rhythms) using multiscale entropy (MSE) to demonstrate the ability of MSE in tracking changes due to

Xiaoxu Kang; Xiaofeng Jia; Romergryko G. Geocadin; Nitish V. Thakor; Anil Maybhate

2009-01-01

176

Event-related synchronization (ERS) in the alpha band — an electrophysiological correlate of cortical idling: A review  

Microsoft Academic Search

EEG desynchronization is a reliable correlate of excited neural structures or activated cortical areas. EEG synchronization within the alpha band may be an electrophysiological correlate of deactivated cortical areas. Such areas are not processing sensory information or motor output and can be considered to be in an idling state. One example of such an idling cortical area is the enhancement

G. Pfurtscheller; A. Stancák; Ch. Neuper

1996-01-01

177

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

PubMed

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

2011-05-01

178

EEG coherence during mental rotation of letters, hands and scenes.  

PubMed

The purpose of the present study was to investigate differences in the electrocortical synchronization pattern during mental rotation of three different object categories as well as six different rotation angles. Therefore, event-related coherence of the electroencephalographic (EEG) activity between selective frontal and parietal electrode pairs of ten subjects was measured during the performance of a mental rotation task consisting of rotation of letters, hands and scenes. Statistical analysis showed an increased coherence of frontal and parietal electrode pairs for the condition LETTER in comparison to the other conditions in the alpha1- (8.5-10 Hz) and alpha2-band (10, 5-12 Hz) supporting the notion of different mental rotation mechanisms for externally and internally represented objects. Additionally decreased coherence of the frontal and parietal electrode pairs was found for the rotation angles 30° to 150° in comparison to the 0° and 180° rotations for the alpha1- and alpha2-band as well as the gamma frequency band (30-45 Hz). It is assumed that this decrease of synchronization reflects the mental rotation process implying that the mental rotation process of 180° differs from the rotation process of all other rotation angles. PMID:23797146

Thomas, Monika; Dalecki, Marc; Abeln, Vera

2013-07-01

179

[Video-EEG in epilepsy diagnostics--when and why?].  

PubMed

Video-EEG (V-EEG) refers to the recording of video picture simultaneously with EEG. A major part of epilepsy patients have to be diagnosed without V-EEG. For a patient having recurrent seizures, the aim is to accomplish V-EEG recording during a seizure. Of the indications of V-EEG, the most important one is diagnosis and differential diagnosis of epilepsy. V-EEG is able to differentiate epileptic seizures from cardiogenic seizures, motor disorders or functional seizures, for example. Essential clinical indications include a more exact classification of epilepsies, evaluation of therapeutic response, and localization of the seizure focus prior to epilepsy surgery. PMID:20095120

Mervaala, Esa; Mäkinen, Riikka; Peltola, Jukka; Eriksson, Kai; Jutila, Leena; Immonen, Arto

2009-01-01

180

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

PubMed Central

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

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

2008-01-01

181

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. PMID:21813300

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

2012-01-01

182

A High Resolution EEG Study of Dynamic Brain Activity during Video Game Play  

Microsoft Academic Search

A high resolution EEG study was conducted on healthy human subjects during video game play. Throughout the game playing experiment short time segments of spontaneous activity were recorded. Spectral analysis was performed on these segments for the theta-wave (4-8 Hz) and alpha-wave (8-13 Hz) bands to investigate the modulatory effects of long-lasting game play and the dynamic changes of spectral

C. Sheikholeslami; H. Yuan; E. J. He; X. Bai; L. Yang; B. He

2007-01-01

183

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

PubMed

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

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

2011-07-21

184

The neurophysiological bases of EEG and EEG measurement: A review for the rest of us.  

PubMed

A thorough understanding of the EEG signal and its measurement is necessary to produce high quality data and to draw accurate conclusions from those data. However, publications that discuss relevant topics are written for divergent audiences with specific levels of expertise: explanations are either at an abstract level that leaves readers with a fuzzy understanding of the electrophysiology involved, or are at a technical level that requires mastery of the relevant physics to understand. A clear, comprehensive review of the origin and measurement of EEG that bridges these high and low levels of explanation fills a critical gap in the literature and is necessary for promoting better research practices and peer review. The present paper addresses the neurophysiological source of EEG, propagation of the EEG signal, technical aspects of EEG measurement, and implications for interpretation of EEG data. PMID:25039563

Jackson, Alice F; Bolger, Donald J

2014-11-01

185

Time-dependent cortical asymmetries induced by emotional arousal: EEG analysis of event-related synchronization and desynchronization in individually defined frequency bands  

Microsoft Academic Search

Event-related desynchronization (ERD) and synchronization (ERS) in the individually defined theta, alpha-1, alpha-2 and alpha-3 frequency bands were measured in 20 healthy subjects in response to International Affective Picture System (IAPS) stimuli with low, moderate and high arousal (LA, MA and HA) content. The 62-channel EEG, skin conductance response (SCR) and heart rate (HR) were simultaneously recorded while subjects viewed

Ljubomir I. Aftanas; Anton A. Varlamov; Sergey V. Pavlov; Viktor P. Makhnev; Natalya V. Reva

2002-01-01

186

Resting state EEG oscillatory power differences in ADHD college students and their peers  

PubMed Central

Background Among the most robust neural abnormalities differentiating individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) from typically developing controls are elevated levels of slow oscillatory activity (e.g., theta) and reduced fast oscillatory activity (e.g., alpha and beta) during resting-state electroencephalography (EEG). However, studies of resting state EEG in adults with ADHD are scarce and yield inconsistent findings. Methods EEG profiles, recorded during a resting-state with eyes-open and eyes-closed conditions, were compared for college students with ADHD (n?=?18) and a nonclinical comparison group (n?=?17). Results The ADHD group showed decreased power for fast frequencies, especially alpha. This group also showed increased power in the slow frequency bands, however, these effects were strongest using relative power computations. Furthermore, the theta/beta ratio measure was reliably higher for the ADHD group. All effects were more pronounced for the eyes-closed compared to the eyes-open condition. Measures of intra-individual variability suggested that brains of the ADHD group were less variable than those of controls. Conclusions The findings of this pilot study reveal that college students with ADHD show a distinct neural pattern during resting state, suggesting that oscillatory power, especially alpha, is a useful index for reflecting differences in neural communication of ADHD in early adulthood. PMID:23249444

2012-01-01

187

Analyzing large data sets acquired through telemetry from rats exposed to organophosphorous compounds: an EEG study.  

PubMed

The organophosphorous compound soman is an acetylcholinesterase inhibitor that causes damage to the brain. Exposure to soman causes neuropathology as a result of prolonged and recurrent seizures. In the present study, long-term recordings of cortical EEG were used to develop an unbiased means to quantify measures of seizure activity in a large data set while excluding other signal types. Rats were implanted with telemetry transmitters and exposed to soman followed by treatment with therapeutics similar to those administered in the field after nerve agent exposure. EEG, activity and temperature were recorded continuously for a minimum of 2 days pre-exposure and 15 days post-exposure. A set of automatic MATLAB algorithms have been developed to remove artifacts and measure the characteristics of long-term EEG recordings. The algorithms use short-time Fourier transforms to compute the power spectrum of the signal for 2-s intervals. The spectrum is then divided into the delta, theta, alpha, and beta frequency bands. A linear fit to the power spectrum is used to distinguish normal EEG activity from artifacts and high amplitude spike wave activity. Changes in time spent in seizure over a prolonged period are a powerful indicator of the effects of novel therapeutics against seizures. A graphical user interface has been created that simultaneously plots the raw EEG in the time domain, the power spectrum, and the wavelet transform. Motor activity and temperature are associated with EEG changes. The accuracy of this algorithm is also verified against visual inspection of video recordings up to 3 days after exposure. PMID:19632275

de Araujo Furtado, Marcio; Zheng, Andy; Sedigh-Sarvestani, Madineh; Lumley, Lucille; Lichtenstein, Spencer; Yourick, Debra

2009-10-30

188

[Clinical importance of EEG changes during the treatment of epilepsy with valproate (depakene chrono)].  

PubMed

In 24 patient with epilepsy in the age fo 6-46 years the EEG was studied before treatment and after stabilization of the initial and corrected dozes of valproate (depakine chrono). The manual analysis with the formalized quantitative estimation of indexes of epileptic activity (El) and computerized mapping of spectral power in the main bands of EEG was carried out. In 18 patients remission of a half-year and more was achieved. Average El before treatment in all group was 15.1 +/- 1.9, on the initial stabilized doze (10-15 mg/kg/day)--4.3 +/- 1.2 (p = 0.000), at increase of a doze > 15 mg/kg/day, on the average it was not revealed of the further change of El. There was significant positive correlation between epileptic activity in EEG, expressed by El and number of attacks in the patient per one month on the moment of EEG research (r = 0.65, t = 6.58). In 6 patients with farmacoresistence the index of epileptic activity was significantly higher (El = 11.7 +/- 4.3), than in the patients with good effect (El = 1.9 +/- 0.8, p < 0.002). In data of the computer analysis under influence of depakine chrono the reduction of power in all bands and leads was observed, except occipital lobes where the increase of alpha-power was observed. This reflects reduction of epileptic activity and restoration of normal EEG, which accompanied the improvement of social and psychic adaptation. The results of the study demonstrate that automated or manual EEG control is important factor of correct selection of a valproate doze during treatment, that allows not only to suppress effectively the attacks, but on the minimal but sufficient doze to reach improvement of psycho-social functioning and to reduce terms of treatment, at the expense of control of an unpredictable relapse of attacks. PMID:11957341

Zenkov, L R

2002-01-01

189

Altered resting state EEG in chronic pancreatitis patients: toward a marker for chronic pain  

PubMed Central

Objectives Electroencephalography (EEG) may be a promising source of physiological biomarkers accompanying chronic pain. Several studies in patients with chronic neuropathic pain have reported alterations in central pain processing, manifested as slowed EEG rhythmicity and increased EEG power in the brain’s resting state. We aimed to investigate novel potential markers of chronic pain in the resting state EEG of patients with chronic pancreatitis. Participants Resting state EEG data from 16 patients with persistent abdominal pain due to chronic pancreatitis (CP) were compared to data from healthy controls matched for age, sex and education. Methods The peak alpha frequency (PAF) and power amplitude in the alpha band (7.5–13 Hz) were compared between groups in four regions of interest (frontal, central, parietal, and occipital) and were correlated with pain duration. Results The average PAF was lowered in CP patients compared with that in healthy controls, observed as a statistically significant between-group effect (mean 9.9 versus 9.5 Hz; P=0.049). Exploratory post hoc analysis of average PAF per region of interest revealed a significant difference, particularly in the parietal and occipital regions. In addition, we observed a significant correlation between pain duration and PAF and showed increased shifts in PAF with longer pain durations. No significant group differences were found in peak power amplitudes. Conclusion CP pain is associated with alterations in spontaneous brain activity, observed as a shift toward lower PAF. This shift correlates with the duration of pain, which demonstrates that PAF has the potential to be a clinically feasible biomarker for chronic pain. These findings could be helpful for assisting diagnosis, establishing optimal treatment, and studying efficacy of new therapeutic agents in chronic pain patients. PMID:24379694

de Vries, Marjan; Wilder-Smith, Oliver HG; Jongsma, Marijtje LA; van den Broeke, Emanuel N; Arns, Martijn; van Goor, Harry; van Rijn, Clementina M

2013-01-01

190

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

191

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

192

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. PMID:21379390

Fingelkurts, Al. A; Fingelkurts, An. A

2010-01-01

193

Energetical bases of extraversion: effort, arousal, EEG, and performance.  

PubMed

This study investigates an extension of H.J. Eysenck's [Eysenck, H.J., 1967. The Biological Basis of Personality. Charles C. Thomas, Springfield, IL] arousal theory of extraversion, incorporating an effort system as a control system for different aspects of arousal. Extraverts were expected to have lower levels of reticocortical arousal than introverts, to invest more effort, and to have lower task performance in a monotonous vigilance task. In a 40-min vigilance task, participants had to react to the shorter of two 1 kHz tones presented binaurally at an event rate of 200 per 10 min. Spontaneous EEG, event-related potential, and performance data of 40 extremely introverted and 41 extremely extraverted students were available for statistical analysis. A tendency for lower arousal levels of extraverts (alpha 2 band), the expected higher effort investment (P300) and a lower performance (hits) of extraverts were found. PMID:16426692

Beauducel, André; Brocke, Burkhard; Leue, Anja

2006-11-01

194

A review of the effects of hypoxia, sleep deprivation and transcranial magnetic stimulation on EEG activity in humans: challenges for drug discovery for Alzheimer's disease.  

PubMed

Different kinds of challenge can alter cognitive process and electroencephalographic (EEG) rhythms in humans. This can provide an alternative paradigms to evaluate treatment effects in drug discovery. Here, we report recent findings on the effects of challenges represented by sleep deprivation (SD), transient hypoxia, and transcranial magnetic stimulation (TMS) in healthy volunteers on cognitive processes and EEG rhythms to build a knowledge platform for novel research for drug discovery in AD Alzheimer's disease (AD). Sleep pressure enhanced frontal delta rhythms (< 4 Hz) during the night, while SD increased slow rhythms in the theta range (4-7 Hz), and reduced resting state alpha rhythms (8-12 Hz) after the following day. Furthermore, SD transiently affected cognitive performance. In contrast, transient experimental hypoxia induced abnormal posterior resting state delta and alpha rhythms in healthy volunteers that resemble the abnormal EEG rhythms typically recorded in AD patients. However, the relationship between the cognitive and EEG effects of such challenges is poorly understood. TMS reversibly interfered with higher brain functions during EEG recordings, but few studies have investigated the relationship between the cognitive and EEG effects of TMS. In conclusion, SD is the most mature challenge model for testing new drugs for AD. Future investigation is needed to better understand the opportunities offered by TMS and hypoxia challenges. PMID:24635844

Babiloni, Claudio; Del Percio, Claudio; Lizio, Roberta; Infarinato, Francesco; Blin, Olivier; Bartres-Faz, David; Dix, Sophie L; Bentivoglio, Marina; Soricelli, Andrea; Bordet, Regis; Rossini, Paolo M; Richardson, Jill C

2014-01-01

195

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. PMID:21332977

2011-01-01

196

Ordinal patterns in epileptic brains: Analysis of intracranial EEG and simultaneous EEG-fMRI  

NASA Astrophysics Data System (ADS)

Epileptic seizures are associated with high behavioral stereotypy of the patients. In the EEG of epilepsy patients characteristic signal patterns can be found during and between seizures. Here we use ordinal patterns to analyze EEGs of epilepsy patients and quantify the degree of signal determinism. Besides relative signal redundancy and the fraction of forbidden patterns we introduce the fraction of under-represented patterns as a new measure. Using the logistic map, parameter scans are performed to explore the sensitivity of the measures to signal determinism. Thereafter, application is made to two types of EEGs recorded in two epilepsy patients. Intracranial EEG shows pronounced determinism peaks during seizures. Finally, we demonstrate that ordinal patterns may be useful for improving analysis of non-invasive simultaneous EEG-fMRI.

Rummel, C.; Abela, E.; Hauf, M.; Wiest, R.; Schindler, K.

2013-06-01

197

Discrete-time model to test links between EEG power and pupil diameter measured by infrared cameras  

NASA Astrophysics Data System (ADS)

Using infrared sensitive cameras and on-line image processing, pupil diameters of awake, eyes-open subjects were measured. Concurrently, electroencephalography (EEG) was monitored and power in the delta (0.5-4Hz), theta (4-8Hz), alpha (8-12Hz), sigma (12-16Hz), beta1 (16-26Hz), and beta2 (26-50Hz) bands were calculated. Pupil diameter and EEG power measured were found to be significantly correlated. Other EEG measures including relative beta (defined here as [power of 16-50Hz]/[power of 4-50Hz]) and centroid frequency of the 4-50Hz band were also found to be significantly related to pupil diameter.

Keegan, Andrew P.; Merritt, S. L.

1995-08-01

198

Neural correlates of action observation and execution in 14-month-old infants: an event-related EEG desynchronization study  

PubMed Central

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. Desynchronization during execution was restricted to central electrode sites, while action observation was associated with a broader desynchronization across frontal, central, and parietal regions. The finding of regional specificity in the overlap between EEG responses to action execution and observation suggests that the rhythm seen in the 6–9 Hz range over central sites in infancy shares certain properties with the adult mu rhythm. The magnitude of EEG desynchronization to action perception and production appears to be smaller for infants than for adults and older children, suggesting developmental change in this measure. PMID:21477187

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

2011-01-01

199

Timing of EEG-based cursor control.  

PubMed

Recent studies show that humans can learn to control the amplitude of electroencephalography (EEG) activity in specific frequency bands over sensorimotor cortex and use it to move a cursor to a target on a computer screen. EEG-based communication could be a valuable new communication and control option for those with severe motor disabilities. Realization of this potential requires detailed knowledge of the characteristic features of EEG control. This study examined the course of EEG control after presentation of a target. At the beginning of each trial, a target appeared at the top or bottom edge of the subject's video screen and 1 sec later a cursor began to move vertically as a function of EEG amplitude in a specific frequency band. In well-trained subjects, this amplitude was high at the time the target appeared and then either remained high (i.e., for a top target) or fell rapidly (i.e., for a bottom target). Target-specific EEG amplitude control began 0.5 sec after the target appeared and appeared to wax and wane with a period of approximately 1 sec until the cursor reached the target (i.e., a hit) or the opposite edge of the screen (i.e., a miss). Accuracy was 90% or greater for each subject. Top-target errors usually occurred later in the trial because of failure to reach and/or maintain sufficiently high amplitude, whereas bottom-target errors usually occurred immediately because of failure to reduce an initially high amplitude quickly enough. The results suggest modifications that could improve performance. These include lengthening the intertrial period, shortening the delay between target appearance and cursor movement, and including time within the trial as a variable in the equation that translates EEG into cursor movement. PMID:9458060

Wolpaw, J R; Flotzinger, D; Pfurtscheller, G; McFarland, D J

1997-11-01

200

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

2012-12-01

201

Impact of Dronabinol on Quantitative Electroencephalogram (qEEG) Measures of Sleep in Obstructive Sleep Apnea Syndrome  

PubMed Central

Study Objectives: To determine the effects of dronabinol on quantitative electroencephalogram (EEG) markers of the sleep process, including power distribution and ultradian cycling in 15 patients with obstructive sleep apnea (OSA). Methods: EEG (C4-A1) relative power (% total) in the delta, theta, alpha, and sigma bands was quantified by fast Fourier transformation (FFT) over 28-second intervals. An activation ratio (AR = [alpha + sigma] / [delta + theta]) also was computed for each interval. To assess ultradian rhythms, the best-fitting cosine wave was determined for AR and each frequency band in each polysomnogram (PSG). Results: Fifteen subjects were included in the analysis. Dronabinol was associated with significantly increased theta power (p = 0.002). During the first half of the night, dronabinol decreased sigma power (p = 0.03) and AR (p = 0.03), and increased theta power (p = 0.0006). At increasing dronabinol doses, ultradian rhythms accounted for a greater fraction of EEG power variance in the delta band (p = 0.04) and AR (p = 0.03). Females had higher amplitude ultradian rhythms than males (theta: p = 0.01; sigma: p = 0.01). Decreasing AHI was associated with increasing ultradian rhythm amplitudes (sigma: p < 0.001; AR: p = 0.02). At the end of treatment, lower relative power in the theta band (p = 0.02) and lower AHI (p = 0.05) correlated with a greater decrease in sleepiness from baseline. Conclusions: This exploratory study demonstrates that in individuals with OSA, dronabinol treatment may yield a shift in EEG power toward delta and theta frequencies and a strengthening of ultradian rhythms in the sleep EEG. Citation: Farabi SS; Prasad B; Quinn L; Carley DW. Impact of dronabinol on quantitative electroencephalogram (qEEG) measures of sleep in obstructive sleep apnea syndrome. J Clin Sleep Med 2014;10(1):49-56. PMID:24426820

Farabi, Sarah S.; Prasad, Bharati; Quinn, Lauretta; Carley, David W.

2014-01-01

202

A review of the EEG effects of the combination of almitrine and raubasine in animals and humans.  

PubMed

During recent years many studies on the electroencephalogram (EEG) changes induced by almitrine-raubasine (Duxil) have been performed in elderly patients and in animals. This article gives an overview of three questions raised by their results. Is there a simple addition of the raubasine and almitrine effects when they are coadministered? Are the EEG effects of this treatment dependent on the patient's disease? To what extent could EEG studies provide some knowledge about the mechanism of action of almitrine-raubasine therapy? In adult (8 months) and aged (22 months) rats the EEG changes induced by the coadministration of almitrine and raubasine were significantly different from the addition of individual almitrine and raubasine EEG effects. In adult rats the coadministration induced slighter EEG changes than those predicted by the addition of almitrine and raubasine effects. In aged rats, the coadministration induced a decrease in delta-theta power not predictable from the effects of almitrine or raubasine. These results could be taken as an indication that some biological targets are common for the two drugs and that the coadministration results in pharmacological effects more complicated than a simple addition of raubasine and almitrine properties. After 3 weeks of treatment in aged healthy subjects, the coadministration induced an increase in the alpha and beta power with a slight decrease of delta and beta-1 powers. In patients with cognitive decline of probable degenerative origin, 3 months of therapy with almitrine-raubasine was mainly associated with a decreased delta and theta power and a slight increase in high frequency components of the alpha band.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2093418

Sebban, C; Tesolin, B; Schatz, C; Malbezin, M; Guez, D

1990-01-01

203

Interindividual differences in alpha and theta power reflect memory performance  

Microsoft Academic Search

Previous research from our laboratory has shown that phasic or event-related changes in alpha and theta band power are related to memory performance. In this study, we test the hypothesis, whether tonic or ‘baseline’ power too is related to memory performance. The ongoing EEG was analyzed for a sample of 60 subjects during five experimental conditions: eyes closed, eyes open,

W. Klimesch; F. Vogt; M. Doppelmayr

1999-01-01

204

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

2001-01-01

205

Music shifts frontal EEG in depressed adolescents.  

PubMed

Recent studies have found that positive affect is associated with greater relative left frontal EEG activation and negative affect is associated with greater relative right frontal EEG activation. Further, chronically depressed adults typically display stable right frontal EEG activation. The present study investigated the effects of music on mood state and right frontal EEG activation associated with chronic depression. Fourteen chronically depressed female adolescents listened to rock music for a 23-minute session. These adolescents were compared with a control sample of chronically depressed female adolescents who were simply asked to sit and relax their minds and their muscles for the same time period. EEG was recorded during baseline, music, and postmusic for three minutes each, and saliva samples were collected before and after the session to determine the effects of the music on stress hormone (cortisol) levels. No group differences or changes were noted for observed or reported mood state. However, cortisol levels decreased and relative right frontal activation was significantly attenuated during and after the music procedure. It was concluded that music had positive effects on the physiological and biochemical measures even though observed and self-reported mood did not change. PMID:9583665

Field, T; Martinez, A; Nawrocki, T; Pickens, J; Fox, N A; Schanberg, S

1998-01-01

206

Change in the characteristics of EEG color noise in Alzheimer's disease.  

PubMed

Neurophysiological experiments support the hypothesis of the presence of critical dynamics of brain activity. This is also manifested by power law of electroencephalography (EEG) power spectra, which can be described by the relation 1/f(alpha). This dependence is a result of internal interactions between parts of the brain and is probably required for optimal processing of information. In Alzheimer's disease, changes in the functional organization of the brain occur, which may be manifested by changes in the alpha coefficient. We compared the average values of alpha for 19 electrodes in the resting EEG record in 110 patients with moderate to severe Alzheimer's disease (Mini-Mental State Examination [MMSE] score = 10-19) with 110 healthy controls. Statistically, the most significant differences are present in the prefrontal areas. In addition to the prefrontal and frontal areas, the largest separation value in the evaluation of receiver operating characteristic (ROC) curves was recorded in the temporal area. The coefficient alpha has few false-positive results in the optimal operating point of the ROC curve, and is thereby highly specific for Alzheimer's disease. PMID:24131619

Vysata, Oldrich; Procházka, Ales; Mares, Jan; Rusina, Robert; Pazdera, Ladislav; Valis, Martin; Kukal, Jaromír

2014-07-01

207

EEG characteristics predict subsequent epilepsy in children with febrile seizure  

Microsoft Academic Search

The role of electroencephalography (EEG) in the work-up of febrile seizure (FS) remains controversial. We investigated the importance of EEG characteristics, especially the localizations of paroxysmal discharges, as predictors for subsequent epilepsy. Patients were referred from the outpatient department for EEG within 7–20days after the seizure. EEGs were classified as paroxysmally abnormal based on the presence of spikes, sharp waves,

Hideaki Kanemura; Sonoko Mizorogi; Kakuro Aoyagi; Kanji Sugita; Masao Aihara

208

CRS-R score in disorders of consciousness is strongly related to spectral EEG at rest.  

PubMed

Patients suffering from disorders of consciousness still present a diagnostic challenge due to the fact that their assessment is mainly based on behavioral scales with their motor responses often being strongly impaired. We therefore focused on resting electroencephalography (EEG) in order to reveal potential alternative measures of the patient's current state independent of rather complex abilities (e.g., language comprehension). Resting EEG was recorded in nine minimally conscious state (MCS) and eight vegetative state/unresponsive wakefulness syndrome (VS/UWS) patients. Behavioral assessments were conducted using the Coma-Recovery Scale-Revised (CRS-R). The signal was analyzed in the frequency domain and association between resting EEG and CRS-R score as well as clinical diagnosis were calculated using Pearson correlation and repeated-measures ANOVAs. The analyses revealed robust positive correlations between CRS-R score and ratios between frequencies above 8 Hz and frequencies below 8 Hz. Furthermore, the frequency of the spectral peak was also highly indicative of the patient's CRS-R score. Concerning differences between clinical diagnosis and healthy controls, it could be revealed that while VS/UWS patients showed higher delta and theta activity than controls, MCS did not differ from controls in this frequency range. Alpha activity, on the other hand, was strongly decreased in both patient groups as compared to controls. The strong relationship between various resting EEG parameters and CRS-R score provides significant clinical relevance. Not only is resting activity easily acquired at bedside, but furthermore, it does not depend on explicit cooperation of the patient. Especially in cases where behavioral assessment is difficult or ambiguous, spectral analysis of resting EEG can therefore complement clinical diagnosis. PMID:23765089

Lechinger, Julia; Bothe, Kathrin; Pichler, Gerald; Michitsch, Gabriele; Donis, Johann; Klimesch, Wolfgang; Schabus, Manuel

2013-09-01

209

Interictal Functional Connectivity of Human Epileptic Networks Assessed by Intracerebral EEG and BOLD Signal Fluctuations  

PubMed Central

In this study, we aimed to demonstrate whether spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal derived from resting state functional magnetic resonance imaging (fMRI) reflect spontaneous neuronal activity in pathological brain regions as well as in regions spared by epileptiform discharges. This is a crucial issue as coherent fluctuations of fMRI signals between remote brain areas are now widely used to define functional connectivity in physiology and in pathophysiology. We quantified functional connectivity using non-linear measures of cross-correlation between signals obtained from intracerebral EEG (iEEG) and resting-state functional MRI (fMRI) in 5 patients suffering from intractable temporal lobe epilepsy (TLE). Functional connectivity was quantified with both modalities in areas exhibiting different electrophysiological states (epileptic and non affected regions) during the interictal period. Functional connectivity as measured from the iEEG signal was higher in regions affected by electrical epileptiform abnormalities relative to non-affected areas, whereas an opposite pattern was found for functional connectivity measured from the BOLD signal. Significant negative correlations were found between the functional connectivities of iEEG and BOLD signal when considering all pairs of signals (theta, alpha, beta and broadband) and when considering pairs of signals in regions spared by epileptiform discharges (in broadband signal). This suggests differential effects of epileptic phenomena on electrophysiological and hemodynamic signals and/or an alteration of the neurovascular coupling secondary to pathological plasticity in TLE even in regions spared by epileptiform discharges. In addition, indices of directionality calculated from both modalities were consistent showing that the epileptogenic regions exert a significant influence onto the non epileptic areas during the interictal period. This study shows that functional connectivity measured by iEEG and BOLD signals give complementary but sometimes inconsistent information in TLE. PMID:21625517

Bettus, Gaelle; Ranjeva, Jean-Philippe; Wendling, Fabrice; Benar, Christian G.; Confort-Gouny, Sylviane; Regis, Jean; Chauvel, Patrick; Cozzone, Patrick J.; Lemieux, Louis; Bartolomei, Fabrice; Guye, Maxime

2011-01-01

210

Estimation of Eye Closure Degree Using EEG Sensors and Its Application in Driver Drowsiness Detection  

PubMed Central

Currently, driver drowsiness detectors using video based technology is being widely studied. Eyelid closure degree (ECD) is the main measure of the video-based methods, however, drawbacks such as brightness limitations and practical hurdles such as distraction of the drivers limits its success. This study presents a way to compute the ECD using EEG sensors instead of video-based methods. The premise is that the ECD exhibits a linear relationship with changes of the occipital EEG. A total of 30 subjects are included in this study: ten of them participated in a simple proof-of-concept experiment to verify the linear relationship between ECD and EEG, and then twenty participated in a monotonous highway driving experiment in a driving simulator environment to test the robustness of the linear relationship in real-life applications. Taking the video-based method as a reference, the Alpha power percentage from the O2 channel is found to be the best input feature for linear regression estimation of the ECD. The best overall squared correlation coefficient (SCC, denoted by r2) and mean squared error (MSE) validated by linear support vector regression model and leave one subject out method is r2 = 0.930 and MSE = 0.013. The proposed linear EEG-ECD model can achieve 87.5% and 70.0% accuracy for male and female subjects, respectively, for a driver drowsiness application, percentage eyelid closure over the pupil over time (PERCLOS). This new ECD estimation method not only addresses the video-based method drawbacks, but also makes ECD estimation more computationally efficient and easier to implement in EEG sensors in a real time way. PMID:25237899

Li, Gang; Chung, Wan-Young

2014-01-01

211

Effect of immobilization on the EEG of the baboon. Comparison with telemetry results from unrestricted animals  

NASA Technical Reports Server (NTRS)

The EEG of the baboon was studied under two very different sets of conditions: 37 were totally immobolized while 12 were studied in their free movements with 4 channel telemetry. For the immobilzed, 3 stages were described: (1) activation, record desynchronized; (2) rest with 13-15 cm/sec rhythm, like the human alpha rhythm stage but with eyes open or closed; (3)relaxation with a decrease in 13-15 rhythm and the appearance of 5-7 cm/sec theta waves, eyelids closed, animal apparently sleeping. For the free animals the rest stage appeared when the animal's attention was not directed anywhere and there was no relaxation stage. It is concluded that the EEG pattern of the immobilized animal that was described as the "relaxation" stage really represents a special functional state which one must distinguish clearly from the physiological stages of sleep.

Bert, J.; Collomb, H.

1980-01-01

212

Biographics art "I know me": image generation aiming at EEG control by biofeedback.  

PubMed

"I know me" is an interactive artwork that produces images based on EEG measurements from human participants. Although artists have previously made some interactive image works, we considered using human physiological information as input because it reflects human feelings better. In this research we were interested in information about human's mental states, such as anger or sadness. Brain activity was observed with EEG, subjected to Fourier analysis and converted into an animation based on a Lissajous curve. We generated images corresponding to alpha or beta waves activity in real time and showed them to the observer. The observer understood his own mental condition from looking at the images, and could potentially control his own mental state with this interactive device. PMID:15684560

Matsunaga, Kosuke; Genda, Etsuo

2005-01-01

213

Effects and after-effects of chewing gum on vigilance, heart rate, EEG and mood.  

PubMed

Research has shown that chewing gum improves attention, although the mechanism for this effect remains unclear. This study investigated the effects and after-effects of chewing gum on vigilance, mood, heart rate and EEG. Participants completed a vigilance task four times; at baseline, with or without chewing gum, and twice post-chewing. EEG alpha and beta power at left frontal and temporal lobes, subjective mood and heart rate were assessed. Chewing gum shortened reaction time and increased the rate of hits, although hits fell during the second post-chewing task. Chewing gum heightened heart rate, but only during chewing. Gum also increased beta power at F7 and T3 immediately post-chewing, but not following the post-chewing tasks. The findings show that chewing gum affects several different indicators of alertness. PMID:24857722

Allen, Andrew P; Jacob, Tim J C; Smith, Andrew P

2014-06-22

214

Temporal dynamics of sensorimotor integration in speech perception and production: independent component analysis of EEG data  

PubMed Central

Activity in anterior sensorimotor regions is found in speech production and some perception tasks. Yet, how sensorimotor integration supports these functions is unclear due to a lack of data examining the timing of activity from these regions. Beta (~20 Hz) and alpha (~10 Hz) spectral power within the EEG ? rhythm are considered indices of motor and somatosensory activity, respectively. In the current study, perception conditions required discrimination (same/different) of syllables pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required covert and overt syllable productions and overt word production. Independent component analysis was performed on EEG data obtained during these conditions to (1) identify clusters of ? components common to all conditions and (2) examine real-time event-related spectral perturbations (ERSP) within alpha and beta bands. 17 and 15 out of 20 participants produced left and right ?-components, respectively, localized to precentral gyri. Discrimination conditions were characterized by significant (pFDR < 0.05) early alpha event-related synchronization (ERS) prior to and during stimulus presentation and later alpha event-related desynchronization (ERD) following stimulus offset. Beta ERD began early and gained strength across time. Differences were found between quiet and noisy discrimination conditions. Both overt syllable and word productions yielded similar alpha/beta ERD that began prior to production and was strongest during muscle activity. Findings during covert production were weaker than during overt production. One explanation for these findings is that ?-beta ERD indexes early predictive coding (e.g., internal modeling) and/or overt and covert attentional/motor processes. ?-alpha ERS may index inhibitory input to the premotor cortex from sensory regions prior to and during discrimination, while ?-alpha ERD may index sensory feedback during speech rehearsal and production. PMID:25071633

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

2014-01-01

215

Sleep EEG composition in the first three months of life in monozygotic and dizygotic twins.  

PubMed

We investigated genetic influence on sleep electroencephalogram (EEG) composition by a classical twin study of monozygotic (MZ) and dizygotic (DZ) twins in the first 3 months of life. Polysomnographic (PSG) recordings were obtained in 10 MZ and 20 DZ twin pairs in the 37th, 46th, and 52nd week of postmenstrual age (PMA). The EEG power spectra were generated on the basis of fast Fourier transformation (FFT). Genetic influence on active sleep/rapid eye movement (AS/REM)] and quiet sleep/non rapid eye movement (QS/NREM) sleep composition was estimated by calculating within pair concordance and the intraclass correlation coefficients (ICCs) for delta (0.5-3.5 Hz), theta (4-7.5 Hz), alpha (8-11.5 Hz), sigma (12-14 Hz), and beta (14.5-20 Hz) at central derivation. MZ twins show higher ICCs than DZ twins for alpha, sigma, and beta spectral powers during QS/NREM sleep in the 37th, 46th, and 52nd week PMA. However, there was no significant difference (P > .05) between the 2 types of twins in absolute differences of EEG spectral power of the alpha, beta, and sigma frequency ranges in the 37th, 46th, and 52nd week PMA. The greatest mean absolute difference within MZ and DZ twin pairs and also between MZ and DZ twin groups was identified in the delta frequency range. Our findings gave an indication of genetic influence on alpha, sigma, and beta frequency ranges in the QS/NREM sleep stage. PMID:24323198

Vucinovic, Mirjana; Kardum, Goran; Bonkovic, Mirjana; Resic, Biserka; Ursic, Anita; Vukovics, Jonatan

2014-07-01

216

"Neural efficiency" of athletes' brain for upright standing: a high-resolution EEG study.  

PubMed

"Neural efficiency" hypothesis posits that neural activity is reduced in experts. Here we tested the hypothesis that compared with non-athletes, elite athletes are characterized by a reduction of cortical activation during an engaging upright standing. EEG (56 channels; Be-plus Eb-Neuro and stabilogram (RGM) data were simultaneously recorded in 10 elite karate, 10 elite fencing athletes, and 12 non-athletes during a simple bipodalic (standard Romberg) and a more engaging monopodalic upright standing. Balance was indexed by body "sway area". The EEG data were spatially enhanced by surface Laplacian estimation. Cortical activity was indexed by task-related power decrease (TRPD) of EEG alpha power (8-12Hz) during monopodalic referenced to bipodalic condition. The body "sway area" was larger during the monopodalic than bipodalic upright standing in all groups. Low-frequency alpha TRPD (about 8-10Hz) was lower in amplitude in the karate and fencing athletes than in the non-athletes at left central, right central, middle parietal, and right parietal areas (p<0.01). Similarly, the amplitude of high-frequency alpha TRPD (10-12Hz) was lower in the karate and fencing athletes than in the non-athletes at right frontal, left central, right central, and middle parietal areas (p<0.03). These results suggest that during monopodalic referenced to less engaging bipodalic condition, the power decrease (i.e. the desynchronization) of cortical activity at alpha rhythms is largely reduced in elite athletes than in non-athletes, in line with the "neural efficiency" hypothesis. The present study extends our understanding of the physiological mechanisms at the basis of the "neural efficiency" for engaging upright standing in elite athletes. PMID:19429191

Del Percio, Claudio; Babiloni, Claudio; Marzano, Nicola; Iacoboni, Marco; Infarinato, Francesco; Vecchio, Fabrizio; Lizio, Roberta; Aschieri, Pierluigi; Fiore, Antonio; Toràn, Giancarlo; Gallamini, Michele; Baratto, Marta; Eusebi, Fabrizio

2009-05-29

217

On the analysis of EEG power, frequency and asymmetry in Parkinson's disease during emotion processing  

PubMed Central

Objective While Parkinson’s disease (PD) has traditionally been described as a movement disorder, there is growing evidence of disruption in emotion information processing associated with the disease. The aim of this study was to investigate whether there are specific electroencephalographic (EEG) characteristics that discriminate PD patients and normal controls during emotion information processing. Method EEG recordings from 14 scalp sites were collected from 20 PD patients and 30 age-matched normal controls. Multimodal (audio-visual) stimuli were presented to evoke specific targeted emotional states such as happiness, sadness, fear, anger, surprise and disgust. Absolute and relative power, frequency and asymmetry measures derived from spectrally analyzed EEGs were subjected to repeated ANOVA measures for group comparisons as well as to discriminate function analysis to examine their utility as classification indices. In addition, subjective ratings were obtained for the used emotional stimuli. Results Behaviorally, PD patients showed no impairments in emotion recognition as measured by subjective ratings. Compared with normal controls, PD patients evidenced smaller overall relative delta, theta, alpha and beta power, and at bilateral anterior regions smaller absolute theta, alpha, and beta power and higher mean total spectrum frequency across different emotional states. Inter-hemispheric theta, alpha, and beta power asymmetry index differences were noted, with controls exhibiting greater right than left hemisphere activation. Whereas intra-hemispheric alpha power asymmetry reduction was exhibited in patients bilaterally at all regions. Discriminant analysis correctly classified 95.0% of the patients and controls during emotional stimuli. Conclusion These distributed spectral powers in different frequency bands might provide meaningful information about emotional processing in PD patients. PMID:24716619

2014-01-01

218

Improving the specificity of EEG for diagnosing Alzheimer's disease.  

PubMed

Objective. EEG has great potential as a cost-effective screening tool for Alzheimer's disease (AD). However, the specificity of EEG is not yet sufficient to be used in clinical practice. In an earlier study, we presented preliminary results suggesting improved specificity of EEG to early stages of Alzheimer's disease. The key to this improvement is a new method for extracting sparse oscillatory events from EEG signals in the time-frequency domain. Here we provide a more detailed analysis, demonstrating improved EEG specificity for clinical screening of MCI (mild cognitive impairment) patients. Methods. EEG data was recorded of MCI patients and age-matched control subjects, in rest condition with eyes closed. EEG frequency bands of interest were ? (3.5-7.5?Hz), ?(1) (7.5-9.5?Hz), ?(2) (9.5-12.5?Hz), and ? (12.5-25?Hz). The EEG signals were transformed in the time-frequency domain using complex Morlet wavelets; the resulting time-frequency maps are represented by sparse bump models. Results. Enhanced EEG power in the ? range is more easily detected through sparse bump modeling; this phenomenon explains the improved EEG specificity obtained in our previous studies. Conclusions. Sparse bump modeling yields informative features in EEG signal. These features increase the specificity of EEG for diagnosing AD. PMID:21660242

Vialatte, François-B; Dauwels, Justin; Maurice, Monique; Musha, Toshimitsu; Cichocki, Andrzej

2011-01-01

219

Multifractal Analysis of Sleep EEG Dynamics in Humans  

Microsoft Academic Search

The aim of this study is to investigate the possibility that human sleep EEGs can be characterized by a multifractal spectrum using wavelet transform modulus maxima (WTMM). We used sleep EEGs taken from healthy subjects during the four stages of sleep and REM sleep. Our findings showed that the dynamics in human sleep EEGs could be adequately described by a

I. H. Song; Y. S. Ji; B. K. Cho; J. H. Ku; Y. J. Chee; J. S. Lee; M. Lee; I. Y. Kim; Sun I. Kim

2007-01-01

220

Developmental Quantitative EEG Differences during Psychomotor Response to Music.  

ERIC Educational Resources Information Center

This study examined the electrophysiological differences between baseline EEG frequencies and EEG frequencies obtained during a psychomotor response to musical stimuli. Subjects were 9 children, with mean age of 5.2 years old. Electrophysiological differences between two different musical conditions were also compared. EEG was recorded during 3…

Flohr, John W.; Miller, Daniel C.

221

EEG profiles of fenfluramine, amobarbital and dextroamphetamine in normal volunteers  

Microsoft Academic Search

A quantitative EEG study in volunteer adults was undertaken to distinguish single oral administrations of 50 and 100 mg amobarbital, 10 mg dextroamphetamine, 40 mg fenfluramine and placebo. Four hour EEG recordings were monitored by frequent auditory reaction time tasks. The EEG changes were measured by digital computer period analysis.

Max Fink; Donald M. Shapiro; Turan M. Itil

1971-01-01

222

Period analysis of the EEG by 6502-based microcomputer  

Microsoft Academic Search

Period analysis has been a popular method of quanti­ tative study of the EEG for many years (Brazier & Finesinger, 1944). The technique involves the measure­ ment of the duration of the major period of the EEG wave. These measurements may then be converted to frequencies so that the mean frequency of the EEG can be determined or the measurements

Tyler S. Lorig

1984-01-01

223

Wavelet analysis for EEG feature extraction in deception detection  

Microsoft Academic Search

Deception detection has important clinical and legal implications. However, the reliability of methods for the discrimination between truthful and deceptive responses is still limited. Efforts to improve reliability have examined measures of central nervous system function such as EEG. However, EEG analyses based on either time- or frequency-domain parameters have had mixed results. Because EEG is a nonstationary signal, the

Anna Caterina Merzagora; Scott Bunce; Meltem Izzetoglu; Banu Onaral

2006-01-01

224

Real time workload classification from an ambulatory wireless EEG system using hybrid EEG electrodes.  

PubMed

This paper describes a compact, lightweight and ultra-low power ambulatory wireless EEG system based upon QUASAR's innovative noninvasive bioelectric sensor technologies. The sensors operate through hair without skin preparation or conductive gels. Mechanical isolation built into the harness permits the recording of high quality EEG data during ambulation. Advanced algorithms developed for this system permit real time classification of workload during subject motion. Measurements made using the EEG system during ambulation are presented, including results for real time classification of subject workload. PMID:19164053

Matthews, R; Turner, P J; McDonald, N J; Ermolaev, K; Manus, T; Shelby, R A; Steindorf, M

2008-01-01

225

EEG correlates of fatigue during administration of a neuropsychological test battery  

PubMed Central

Objective Mental fatigue, a poorly understood symptom of sports-related concussion, ideally requires assessment across multiple modalities. Our study aimed to examine mental fatigue effects among ten neurologically normal, athletically active students undergoing typical concussion testing. It is our intention to ultimately address the question whether fatigue effects due to mild traumatic brain injury (mTBI) may become confounded with fatigue effects due to testing effort. Methods Fourteen athletically active and neurologically normal volunteers were initially recruited from Penn State University. Self-reported fatigue, neuropsychological performance, and electroencephalographic (EEG) activity were measured throughout the whole testing duration. EEG measures in frequency domain (e.g., relative power of theta, alpha & beta bands) were examined over the course of neuropsychological (NP) test administration. Results Predicted fatigue effects over the course of testing included: (a) increased self-reported fatigue; (b) increased errors on the Stroop Interference Test; (c) significantly increased relative power of theta activity during the Stroop Interference Test in frontal-central and parietal regions; and (d) migration of alpha activation from the occipital to anterior (left parietal and pre-central) regions during the Stroop Interference task administered at the beginning compared with the end of testing. Conclusions Results supported predictions related to subjective fatigue and cognitive performance and offered partial support for predictions related to EEG activation patterns over the course of administering the NP testing. Significance Neurologically intact and athletically active college students demonstrate effects related to fatigue after undergoing a typical sports concussion assessment battery, including an increase in subjectively experienced fatigue, a decrease in cognitive task performance accuracy and associated modulations in EEG activity. This finding should be considered by clinical practitioners while evaluating the symptoms of concussion and making a decision regarding the return-to-sport participation. PMID:21798799

Barwick, Fiona; Arnett, Peter; Slobounov, Semyon

2011-01-01

226

NORMAL SLEEP HOMEOSTASIS AND LACK OF EPILEPSY PHENOTYPE IN GABAA RECEPTOR 3 SUBUNIT-KNOCKOUT MICE  

E-print Network

NORMAL SLEEP HOMEOSTASIS AND LACK OF EPILEPSY PHENOTYPE IN GABAA RECEPTOR 3 SUBUNIT-KNOCKOUT MICE R spectral analysis showed no difference between ge- notypes during non rapid-eye movement (NREM) sleep or at waking­NREM sleep transitions. EEG power in the spindle frequency range (10­15 Hz) was significantly

Huguenard, John R.

227

Production of intracellular IL-1alpha, IL-1beta, and IL-1Ra isoforms by activated human dermal and synovial fibroblasts: phenotypic differences between human dermal and synovial fibroblasts.  

PubMed

We compared the production of IL-1alpha, IL-1beta, and of IL-1Ra isoforms by cultured human dermal (HDF) and synovial fibroblasts (HSF) in response to IL-1alpha, TNF-alpha, or direct T cell membrane contact. IL-1Ra was constitutively present in the cell lysates of cultured HDF and its synthesis increased in stimulated cells, whereas IL-1Ra was present in low amounts in the supernatants. Secreted IL-1Ra (sIL-1Ra) and intracellular IL-1Ra type 1 (icIL-1Ra1) mRNA levels followed the same pattern. In stimulated HDF, IL-1alpha and IL-1beta were increased intracellularly but remained undetectable in the supernatants. In HSF, IL-1Ra levels increased in both cell lysates and supernatants upon stimulation. IL-1beta was only present in HSF cell lysates after stimulation, whereas IL-1alpha was undetectable. Both sIL-1Ra and icIL-1Ra1 mRNAs were detected in stimulated HSF. icIL-1Ra1 was the predominant intracellular isoform in both cell types. In conclusion, stimulated HDF produce high amounts of intracellular IL-1Ra, IL-1alpha, and IL-1beta. In contrast, HSF synthesized both intracellular and secreted IL-1Ra, whereas IL-1beta was present only in cell lysates. The presence of high amounts of icIL-1Ra1 and intracellular IL-1alpha in HDF suggests that these cytokines may carry out important function inside cells. PMID:15036245

Maret, Michel; Chicheportiche, Rachel; Dayer, Jean-Michel; Gabay, Cem

2004-03-01

228

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.

229

The processing and transmission of EEG data  

NASA Technical Reports Server (NTRS)

Interest in sleep research was stimulated by the discovery of a number of physiological changes that occur during sleep and by the observed effects of sleep on physical and mental performance and status. The use of the relatively new methods of EEG measurement, transmission, and automatic scoring makes sleep analysis and categorization feasible. Sleep research involving the use of the EEG as a fundamental input has the potential of answering many unanswered questions involving physical and mental behavior, drug effects, circadian rhythm, and anesthesia.

Schulze, A. E.

1974-01-01

230

A double-blind investigation of the relationship between seizure activity and the sleep EEG following EEG biofeedback training  

Microsoft Academic Search

The sleep EEGs of eight medically refractory epileptic patients were examined as part of a double-blind, ABA crossover study designed to determine the effectiveness of EEG biofeedback for the control of seizures. The patients were initially reinforced for one of three EEG criteria recorded from electrodes placed over sensorimotor cortex: (a) suppression of 3- to 7-Hz activity, (b) enhancement of

S. F. Whitsett; J. F. Lubar; G. S. Holder; W. E. Pamplin; H. S. Shabsin

1982-01-01

231

[Quantitative EEG analysis of the effects of carbocromen, pentetrazole, beta-methyldigoxin, and strophantin-K in normal human volunteers (author's transl)].  

PubMed

With EEG-interval analysis we studied the influence on C.N.S. of some drugs normally used for cardiovascular diseases: carbochromen, pentetrazole, beta-methyldigoxin and Strophantin-K. All investigated drugs induced activation of alpha-waves, especially in frontal areas with primary small alpha-activity. Dominant alpha-frequency was accelerated. These results confirm the direct and stimulating effects of these drugs on C.N.S. in therapeutic doses. Alpha-acceleration may not only indicate psychostimulation but also indicate epileptogenic effects. All these drugs may provoke epileptic seizures in toxic doses. PMID:616928

Maxion, H; Klein, G; Wolf, B; Zöllner, U

1977-09-01

232

Alpha Particle  

NASA Astrophysics Data System (ADS)

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

Murdin, P.

2000-11-01

233

EEG Power During Waking and NREM Sleep in Primary Insomnia  

PubMed Central

Objective: Pathophysiological models of insomnia invoke the concept of 24-hour hyperarousal, which could lead to symptoms and physiological findings during waking and sleep. We hypothesized that this arousal could be seen in the waking electroencephalogram (EEG) of individuals with primary insomnia (PI), and that waking EEG power would correlate with non-REM (NREM) EEG. Methods: Subjects included 50 PI and 32 good sleeper controls (GSC). Five minutes of eyes closed waking EEG were collected at subjects' usual bedtimes, followed by polysomnography (PSG) at habitual sleep times. An automated algorithm and visual editing were used to remove artifacts from waking and sleep EEGs, followed by power spectral analysis to estimate power from 0.5–32 Hz. Results: We did not find significant differences in waking or NREM EEG spectral power of PI and GSC. Significant correlations between waking and NREM sleep power were observed across all frequency bands in the PI group and in most frequency bands in the GSC group. Conclusions: The absence of significant differences between groups in waking or NREM EEG power suggests that our sample was not characterized by a high degree of cortical arousal. The consistent correlations between waking and NREM EEG power suggest that, in samples with elevated NREM EEG beta activity, waking EEG power may show a similar pattern. Citation: Wu YM; Pietrone R; Cashmere JD; Begley A; Miewald JM; Germain A; Buysse DJ. EEG power during waking and NREM sleep in primary insomnia. J Clin Sleep Med 2013;9(10):1031-1037. PMID:24127147

Wu, You Meme; Pietrone, Regina; Cashmere, J. David; Begley, Amy; Miewald, Jean M.; Germain, Anne; Buysse, Daniel J.

2013-01-01

234

A Physiology-Based Seizure Detection System for Multichannel EEG  

PubMed Central

Background Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. Electroencephalogram (EEG) signals play a critical role in the diagnosis of epilepsy. Multichannel EEGs contain more information than do single-channel EEGs. Automatic detection algorithms for spikes or seizures have traditionally been implemented on single-channel EEG, and algorithms for multichannel EEG are unavailable. Methodology This study proposes a physiology-based detection system for epileptic seizures that uses multichannel EEG signals. The proposed technique was tested on two EEG data sets acquired from 18 patients. Both unipolar and bipolar EEG signals were analyzed. We employed sample entropy (SampEn), statistical values, and concepts used in clinical neurophysiology (e.g., phase reversals and potential fields of a bipolar EEG) to extract the features. We further tested the performance of a genetic algorithm cascaded with a support vector machine and post-classification spike matching. Principal Findings We obtained 86.69% spike detection and 99.77% seizure detection for Data Set I. The detection system was further validated using the model trained by Data Set I on Data Set II. The system again showed high performance, with 91.18% detection of spikes and 99.22% seizure detection. Conclusion We report a de novo EEG classification system for seizure and spike detection on multichannel EEG that includes physiology-based knowledge to enhance the performance of this type of system. PMID:23799053

Shen, Chia-Ping; Liu, Shih-Ting; Zhou, Wei-Zhi; Lin, Feng-Seng; Lam, Andy Yan-Yu; Sung, Hsiao-Ya; Chen, Wei; Lin, Jeng-Wei; Chiu, Ming-Jang; Pan, Ming-Kai; Kao, Jui-Hung; Wu, Jin-Ming; Lai, Feipei

2013-01-01

235

Optimizing microsurgical skills with EEG neurofeedback  

Microsoft Academic Search

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)

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

2009-01-01

236

Inferring Seizure Frequency From Brief EEG Recordings  

PubMed Central

Routine EEGs remain a cornerstone test in caring for people with epilepsy. Although rare, a self-limited seizure (clinical or electrographic only) may be observed during such brief EEGs. The implications of observing a seizure in this situation, especially with respect to inferring the underlying seizure frequency, are unclear. The issue is complicated by the inaccuracy of patient-reported estimations of seizure frequency. The treating clinician is often left to wonder whether the single seizure indicates very frequent seizures, or if it is of lesser significance. We applied standard concepts of probabilistic inference to a simple model of seizure incidence to provide some guidance for clinicians facing this situation. Our analysis establishes upper and lower bounds on the seizure rate implied by observing a single seizure during routine EEG. Not surprisingly, with additional information regarding the expected seizure rate, these bounds can be further constrained. This framework should aid the clinician in applying a more principled approach toward decision making in the setting of a single seizure on a routine EEG. PMID:23545768

Westover, M. Brandon; Bianchi, Matt T.; Shafi, Mouhsin; Hoch, Daniel B.; Cole, Andrew J.; Chiappa, Keith; Cash, Sydney S.

2012-01-01

237

Automated Sleep Quality Measurement using EEG Signal  

E-print Network

Automated Sleep Quality Measurement using EEG Signal -First Step Towards a Domain Specific Music suffer from sleep problems. Music therapy, as a non-medication approach to mitigating sleep problems, has according to their sleep quality. The proposed sys- tem requires multidisciplinary efforts including

Wang, Ye

238

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

1971-01-01

239

Illumination influences working memory: an EEG study.  

PubMed

Illumination conditions appear to influence working efficacy in everyday life. In the present study, we obtained electroencephalogram (EEG) correlates of working-memory load, and investigated how these waveforms are modulated by illumination conditions. We hypothesized that illumination conditions may affect cognitive performance. We designed an EEG study to monitor and record participants' EEG during the Sternberg working memory task under four different illumination conditions. Illumination conditions were generated with a factorial design of two color-temperatures (3000 and 7100 K) by two illuminance levels (150 and 700 lx). During a working memory task, we observed that high illuminance led to significantly lower frontal EEG theta activity than did low illuminance. These differences persisted despite no significant difference in task performance between illumination conditions. We found that the latency of an early event-related potential component, such as N1, was significantly modulated by the illumination condition. The fact that the illumination condition affects brain activity but not behavioral performance suggests that the lighting conditions used in the present study did not influence the performance stage of behavioral processing. Nevertheless, our findings provide objective evidence that illumination conditions modulate brain activity. Further studies are necessary to refine the optimal lighting parameters for facilitating working memory. PMID:23694704

Park, Jin Young; Min, Byoung-Kyong; Jung, Young-Chul; Pak, Hyensou; Jeong, Yeon-Hong; Kim, Eosu

2013-09-01

240

Hemispheric Relationships in Composing: An EEG Study.  

ERIC Educational Resources Information Center

The left hemisphere of the brain is analytic and "particularistic" in orientation--focusing on individual elements within a field and analyzing them sequentially. The right hemisphere of the brain is holistic or relational in processing, and is predisposed to see wholes simultaneously. One of the most prominant features of the EEG is the asymmetry…

Glassner, Benjamin M.

241

EEG Spectral Analysis of Relaxation Techniques  

Microsoft Academic Search

The acute central nervous system effects of relaxation techniques (RT) have not been systematically studied. We conducted a controlled, randomized study of the central nervous system effects of RT using spectral analysis of EEG activity. Thirty-six subjects were randomized to either RT or a music comparison condition. After listening to an RT audiotape or music audiotapes daily for 6 weeks,

Gregg D. Jacobs; Richard Friedman

2004-01-01

242

EEG-based Estimation of Cognitive Fatigue  

Microsoft Academic Search

We measured multichannel EEG spectra during a continuous mental arithmetic task and created statistical learning models of cognitive fatigue for single subjects. Sixteen subjects (4 F, 18-38 y) viewed 4-digit problems on a computer, solved the problems, and pressed keys to respond (inter-trial interval = 1 s). Subjects performed until either they felt exhausted or three hours had elapsed. Pre-

Leonard J. Trejo; Rebekah Kochavi; Karla Kubitz; Leslie D. Montgomery; Roman Rosipal; Bryan Matthews

243

Impact of EEG biofeedback on event-related potentials (ERPs) in attention-deficit hyperactivity (ADHD) children  

Microsoft Academic Search

Impact of EEG biofeedback on event-related potentials (ERPs) in attention-deficit hyperactivity (ADHD) children. Introduction: ADHD is one of the most widely spread condition of school aged children affecting 5% of children of this age.The core clinical signs of ADHD are inattention, restlessness and impulsivity. According to various authors direct measures of attention are of two types: 1. Recording the alpha

Sophio Bakhtadze; Marine Janelidze; Nana Khachapuridze

2011-01-01

244

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

E-print Network

Background: Real-time fMRI neurofeedback (rtfMRI-nf) is a promising approach for studies and treatment of major depressive disorder (MDD). EEG performed simultaneously with rtfMRI-nf procedure allows independent evaluation of rtfMRI-nf effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been related to simultaneously acquired fMRI data. Methods: We performed the first study combining rtfMRI-nf with simultaneous (passive) EEG recordings. MDD patients in the experimental group (n=13) learned to upregulate BOLD activity of the left amygdala using rtfMRI-nf during a positive emotion induction task. MDD patients in the control group (n=11) were provided with sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper-alpha band and BOLD activity across the brain were examined. Results: Participants in the experimental group showed positive average changes in frontal EEG asymmetry during the ...

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

2014-01-01

245

Alpha-Theta Effects Associated with Ageing during the Stroop Test  

PubMed Central

The Stroop effect is considered as a standard attentional measure to study conflict resolution in humans. The response of the brain to conflict is supposed to change over time and it is impaired in certain pathological conditions. Neuropsychological Stroop test measures have been complemented with electroencephalography (EEG) techniques to evaluate the mechanisms in the brain that underlie conflict resolution from the age of 20 to 70. To study the changes in EEG activity during life, we recruited a large sample of healthy subjects of different ages that included 90 healthy individuals, divided by age into decade intervals, which performed the Stroop test while recording a 14 channel EEG. The results highlighted an interaction between age and stimulus that was focused on the prefrontal (Alpha and Theta band) and Occipital (Alpha band) areas. We concluded that behavioural Stroop interference is directly influenced by opposing Alpha and Theta activity and evolves across the decades of life. PMID:24867024

Nombela, Cristina; Nombela, Manuel; Castell, Pedro; Garcia, Teodoro; Lopez-Coronado, Juan; Herrero, Maria Trinidad

2014-01-01

246

Modulation of EEG Functional Connectivity Networks in Subjects Undergoing Repetitive Transcranial Magnetic Stimulation  

PubMed Central

Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique that utilizes magnetic fluxes to alter cortical activity. Continuous theta-burst repetitive TMS (cTBS) results in long-lasting decreases in indices of cortical excitability, and alterations in performance of behavioral tasks. We investigated the effects of cTBS on cortical function via functional connectivity and graph theoretical analysis of EEG data. Thirty-one channel resting-state EEG recordings were obtained before and after 40 s of cTBS stimulation to the left primary motor cortex. Functional connectivity between nodes was assessed in multiple frequency bands using lagged max-covariance, and subsequently thresholded to construct undirected graphs. After cTBS, we find widespread decreases in functional connectivity in the alpha band. There are also simultaneous increases in functional connectivity in the high-beta bands, especially amongst anterior and interhemispheric connections. The analysis of the undirected graphs reveals that interhemispheric and interregional connections are more likely to be modulated after cTBS than local connections. There is also a shift in the topology of network connectivity, with an increase in the clustering coefficient after cTBS in the beta bands, and a decrease in clustering and increase in path length in the alpha band, with the alpha-band connectivity primarily decreased near the site of stimulation. cTBS produces widespread alterations in cortical functional connectivity, with resulting shifts in cortical network topology. PMID:23471637

Shafi, Mouhsin M.; Westover, M. Brandon; Oberman, Lindsay; Cash, Sydney S.; Pascual-Leone, Alvaro

2014-01-01

247

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. PMID:19454962

Spence, Sarah J; Schneider, Mark T

2009-01-01

248

Screening EEG in Aircrew Selection: Clinical Aerospace Neurology Perspective  

NASA Technical Reports Server (NTRS)

As clinical aerospace neurologists we do not favor using screening EEG in pilot selection on unselected and otherwise asymptomatic individuals. The role of EEG in aviation screening should be as an adjunct to diagnosis, and the decision to disqualify a pilot should never be based solely on the EEG. Although a policy of using a screening EEG in an unselected population might detect an individual with a potentially increased relative risk, it would needlessly exclude many applicants who would probably never have a seizure. A diagnostic test performed on an asymptomatic individual without clinical indications, in a population with a low prevalence of disease (seizure) may be of limited or possibly detrimental value. We feel that rather than do EEGs on all candidates, a better approach would be to perform an EEG for a specific indication, such as family history of seizure, single convulsion (seizure) , history of unexplained loss of consciousness or head injury. Routine screening EEGs in unselected aviation applications are not done without clinical indication in the U.S. Air Force, Navy, or NASA. The USAF discontinued routine screening EEGs for selection in 1978, the U.S. Navy discontinued it in 1981 , and NASA discontinued it in 1995. EEG as an aeromedical screening tool in the US Navy dates back to 1939. The US Navy routinely used EEGs to screen all aeromedical personnel from 1961 to 1981. The incidence of epileptiform activity on EEG in asymptomatic flight candidates ranges from 0.11 to 2.5%. In 3 studies of asymptomatic flight candidates with epileptiform activity on EEG followed for 2 to 15 years, 1 of 31 (3.2%), 1 of 30 (3.3%), and 0 of 14 (0%) developed a seizure, for a cumulative risk of an individual with an epileptiform EEG developing a seizure of 2.67% (2 in 75). Of 28,658 student naval aviation personnel screened 31 had spikes and/or slow waves on EEG, and only 1 later developed a seizure. Of the 28,627 who had a normal EEG, 4 later developed seizures, or .0139% (4/28627). After review of the value of the EEG as a screening tool, the US Navy now uses EEG only for certain clinical indications (head injury, unexplained loss of consciousness, family history of epilepsy, and abnormal neurological exam). Currently the US Navy does not use EEG for screening for any flight applicant without a neurologic indication. In the US Navy, an electroencephalographic pattern is determined to be epileptiform by a neurologist.

Clark, Jonathan B.; Riley, Terrence

2001-01-01

249

EEG sleep slow-wave activity as a mirror of cortical maturation.  

PubMed

Deep (slow wave) sleep shows extensive maturational changes from childhood through adolescence, which is reflected in a decrease of sleep depth measured as the activity of electroencephalographic (EEG) slow waves. This decrease in sleep depth is paralleled by massive synaptic remodeling during adolescence as observed in anatomical studies, which supports the notion that adolescence represents a sensitive period for cortical maturation. To assess the relationship between slow-wave activity (SWA) and cortical maturation, we acquired sleep EEG and magnetic resonance imaging data in children and adolescents between 8 and 19 years. We observed a tight relationship between sleep SWA and a variety of indexes of cortical maturation derived from magnetic resonance (MR) images. Specifically, gray matter volumes in regions correlating positively with the activity of slow waves largely overlapped with brain areas exhibiting an age-dependent decrease in gray matter. The positive relationship between SWA and cortical gray matter was present also for power in other frequency ranges (theta, alpha, sigma, and beta) and other vigilance states (theta during rapid eye movement sleep). Our findings indicate a strong relationship between sleep EEG activity and cortical maturation. We propose that in particular, sleep SWA represents a good marker for structural changes in neuronal networks reflecting cortical maturation during adolescence. PMID:20624840

Buchmann, Andreas; Ringli, Maya; Kurth, Salomé; Schaerer, Margot; Geiger, Anja; Jenni, Oskar G; Huber, Reto

2011-03-01

250

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. PMID:19298626

McMenamin, Brenton W.; Shackman, Alexander J.; Maxwell, Jeffrey S.; Greischar, Lawrence L.; Davidson, Richard J.

2008-01-01

251

Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.  

PubMed

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

2012-01-01

252

Abnormal Parietal Brain Function in ADHD: Replication and Extension of Previous EEG Beta Asymmetry Findings  

PubMed Central

Background: Abundant work indicates ADHD abnormal posterior brain structure and function, including abnormal structural and functional asymmetries and reduced corpus callosum size. However, this literature has attracted considerably less research interest than fronto-striatal findings. Objective: To help address this imbalance, the current study replicates and extends our previous work showing abnormal parietal brain function in ADHD adults during the Conner’s Continuous Performance Test (CPT). Method: Our previous study found that ADHD adults had increased rightward EEG beta (16–21?Hz) asymmetry in inferior parietal brain regions during the CPT (p?=?0.00001), and that this metric exhibited a lack of normal correlation (i.e., observed in controls) with beta asymmetry at temporal–parietal regions. We re-tested these effects in a new ADHD sample and with both new and old samples combined. We additionally examined: (a) EEG asymmetry in multiple frequency bands, (b) unilateral effects for all asymmetry findings, and (c) the association between EEG asymmetry and a battery of cognitive tests. Results: We replicated our original findings by demonstrating abnormal rightward inferior parietal beta asymmetry in adults with ADHD during the CPT, and again this metric exhibited abnormal reduced correlation to temporal–parietal beta asymmetry. Novel analyses also demonstrated a broader pattern of rightward beta and theta asymmetry across inferior, superior, and temporal–parietal brain regions, and showed that rightward parietal asymmetry in ADHD was atypically associated with multiple cognitive tests. Conclusion: Abnormal increased rightward parietal EEG beta asymmetry is an important feature of ADHD. We speculate that this phenotype may occur with any form of impaired capacity for top-down task-directed control over sensory encoding functions, and that it may reflect associated increase of attentional shifting and compensatory sustained/selective attention. PMID:25104941

Hale, T. Sigi; Kane, Andrea M.; Tung, Kelly L.; Kaminsky, Olivia; McGough, James J.; Hanada, Grant; Loo, Sandra K.

2014-01-01

253

Tackling creativity at its roots: evidence for different patterns of EEG ? activity related to convergent and divergent modes of task processing.  

PubMed

The distinction between convergent and divergent cognitive processes given by Guilford (1956) had a strong influence on the empirical research on creative thinking. Neuroscientific studies typically find higher event-related synchronization in the EEG alpha rhythm for individuals engaged in creative ideation tasks compared to intelligence-related tasks. This study examined, whether these neurophysiological effects can also be found when both cognitive processing modes (convergent vs. divergent) are assessed by means of the same task employing a simple variation of instruction. A sample of 55 participants performed the alternate uses task as well as a more basic word association task while EEG was recorded. On a trial-by-trial basis, participants were either instructed to find a most common solution (convergent condition) or a most uncommon solution (divergent condition). The answers given in the divergent condition were in both tasks significantly more original than those in the convergent condition. Moreover, divergent processing was found to involve higher task-related EEG alpha power than convergent processing in both the alternate uses task and the word association task. EEG alpha synchronization can hence explicitly be associated with divergent cognitive processing rather than with general task characteristics of creative ideation tasks. Further results point to a differential involvement of frontal and parietal cortical areas by individuals of lower versus higher trait creativity. PMID:22390860

Jauk, Emanuel; Benedek, Mathias; Neubauer, Aljoscha C

2012-05-01

254

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. PMID:19939972

Smirnov, Michael S.

2010-01-01

255

Memories of attachment hamper EEG cortical connectivity in dissociative patients.  

PubMed

In this study, we evaluated cortical connectivity modifications by electroencephalography (EEG) lagged coherence analysis, in subjects with dissociative disorders and in controls, after retrieval of attachment memories. We asked thirteen patients with dissociative disorders and thirteen age- and sex-matched healthy controls to retrieve personal attachment-related autobiographical memories through adult attachment interviews (AAI). EEG was recorded in the closed eyes resting state before and after the AAI. EEG lagged coherence before and after AAI was compared in all subjects. In the control group, memories of attachment promoted a widespread increase in EEG connectivity, in particular in the high-frequency EEG bands. Compared to controls, dissociative patients did not show an increase in EEG connectivity after the AAI. Conclusions: These results shed light on the neurophysiology of the disintegrative effect of retrieval of traumatic attachment memories in dissociative patients. PMID:24121863

Farina, Benedetto; Speranza, Anna Maria; Dittoni, Serena; Gnoni, Valentina; Trentini, Cristina; Vergano, Carola Maggiora; Liotti, Giovanni; Brunetti, Riccardo; Testani, Elisa; Della Marca, Giacomo

2014-08-01

256

The cholinergic system, EEG and sleep.  

PubMed

Acetylcholine is a potent excitatory neurotransmitter, crucial for cognition and the control of alertness and arousal. Vigilance-specific recordings of the electroencephalogram (EEG) potently reflect thalamo-cortical and brainstem-cortical cholinergic activity that drives theta rhythms and task-specific cortical (de-synchronisation. Additionally, cholinergic projections from the basal forebrain act as a relay centre for the brainstem-cortical arousal system, but also directly modulate cortical activity, and thus promote wakefulness or rapid-eye movement (REM) sleep. Disease states such as sleep disorders, dementia and certain types of epilepsy are a further reflection of the potent cholinergic impact on CNS physiology and function, and highlight the relevance and inter-dependence of sleep and EEG. With novel technologies and computational tools now becoming available, advanced mechanistic insights may be gained and new avenues explored for diagnostics and therapeutics. PMID:21238497

Platt, Bettina; Riedel, Gernot

2011-08-10

257

Resting EEG Discrimination of Early Stage Alzheimer's Disease from Normal Aging Using Inter-Channel Coherence Network Graphs  

PubMed Central

Amnestic mild cognitive impairment (MCI) is a degenerative neurological disorder at the early stage of Alzheimer’s disease (AD). This work is a pilot study aimed at developing a simple scalp-EEG-based method for screening and monitoring MCI and AD. Specifically, the use of graphical analysis of inter-channel coherence of resting EEG for the detection of MCI and AD at early stages is explored. Resting EEG records from 48 age-matched subjects (mean age 75.7 years)—15 normal controls (NC), 16 with early stage MCI, and 17 with early stage AD—are examined. Network graphs are constructed using pairwise inter-channel coherence measures for delta-theta, alpha, beta, and gamma band frequencies. Network features are computed and used in a support vector machine model to discriminate among the three groups. Leave-one-out cross-validation discrimination accuracies of 93.6% for MCI vs. NC (p<0.0003), 93.8% for AD vs. NC (p<0.0003), and 97.0% for MCI vs. AD (p<0.0003) are achieved. These results suggest the potential for graphical analysis of resting EEG inter-channel coherence as an efficacious method for noninvasive screening for MCI and early AD. PMID:23483374

McBride, Joseph; Zhao, Xiaopeng; Munro, Nancy; Smith, Charles; Jicha, Gregory; Jiang, Yang

2013-01-01

258

Resting EEG discrimination of early stage Alzheimer's disease from normal aging using inter-channel coherence network graphs.  

PubMed

Amnestic mild cognitive impairment (MCI) is a degenerative neurological disorder at the early stage of Alzheimer's disease (AD). This work is a pilot study aimed at developing a simple scalp-EEG-based method for screening and monitoring MCI and AD. Specifically, the use of graphical analysis of inter-channel coherence of resting EEG for the detection of MCI and AD at early stages is explored. Resting EEG records from 48 age-matched subjects (mean age 75.7 years)--15 normal controls (NC), 16 with early-stage MCI, and 17 with early-stage AD--are examined. Network graphs are constructed using pairwise inter-channel coherence measures for delta-theta, alpha, beta, and gamma band frequencies. Network features are computed and used in a support vector machine model to discriminate among the three groups. Leave-one-out cross-validation discrimination accuracies of 93.6% for MCI vs. NC (p < 0.0003), 93.8% for AD vs. NC (p < 0.0003), and 97.0% for MCI vs. AD (p < 0.0003) are achieved. These results suggest the potential for graphical analysis of resting EEG inter-channel coherence as an efficacious method for noninvasive screening for MCI and early AD. PMID:23483374

McBride, Joseph; Zhao, Xiaopeng; Munro, Nancy; Smith, Charles; Jicha, Gregory; Jiang, Yang

2013-06-01

259

EEG Correlates of Action Observation in Humans  

Microsoft Academic Search

To investigate electrophysiological correlates of action observation electroencephalogram (EEG) was recorded while participants\\u000a observed repetitive biological (human) or non-biological movements (at a rate of 2 Hz). Steady-state evoked potentials were\\u000a analyzed and their neural sources were investigated using low resolution electromagnetic tomography analysis (LORETA). Results\\u000a revealed significantly higher activation in the primary motor and premotor cortex, supplementary motor area as well

Elisa Mira Holz; Michael Doppelmayr; Wolfgang Klimesch; Paul Sauseng

2008-01-01

260

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

2005-01-01

261

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

2005-01-01

262

Automatic detection of EEG artefacts arising from head movements using EEG and gyroscope signals.  

PubMed

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

2013-07-01

263

EEG and Neuronal Activity Topography analysis can predict effectiveness of shunt operation in idiopathic normal pressure hydrocephalus patients?  

PubMed Central

Idiopathic normal pressure hydrocephalus (iNPH) is a neuropsychiatric syndrome characterized by gait disturbance, cognitive impairment and urinary incontinence that affect elderly individuals. These symptoms can potentially be reversed by cerebrospinal fluid (CSF) drainage or shunt operation. Prior to shunt operation, drainage of a small amount of CSF or “CSF tapping” is usually performed to ascertain the effect of the operation. Unfortunately, conventional neuroimaging methods such as single photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI), as well as electroencephalogram (EEG) power analysis seem to have failed to detect the effect of CSF tapping on brain function. In this work, we propose the use of Neuronal Activity Topography (NAT) analysis, which calculates normalized power variance (NPV) of EEG waves, to detect cortical functional changes induced by CSF tapping in iNPH. Based on clinical improvement by CSF tapping and shunt operation, we classified 24 iNPH patients into responders (N = 11) and nonresponders (N = 13), and performed both EEG power analysis and NAT analysis. We also assessed correlations between changes in NPV and changes in functional scores on gait and cognition scales before and after CSF tapping. NAT analysis showed that after CSF tapping there was a significant decrease in alpha NPV at the medial frontal cortex (FC) (Fz) in responders, while nonresponders exhibited an increase in alpha NPV at the right dorsolateral prefrontal cortex (DLPFC) (F8). Furthermore, we found correlations between cortical functional changes and clinical symptoms. In particular, delta and alpha NPV changes in the left-dorsal FC (F3) correlated with changes in gait status, while alpha and beta NPV changes in the right anterior prefrontal cortex (PFC) (Fp2) and left DLPFC (F7) as well as alpha NPV changes in the medial FC (Fz) correlated with changes in gait velocity. In addition, alpha NPV changes in the right DLPFC (F8) correlated with changes in WMS-R Mental Control scores in iNPH patients. An additional analysis combining the changes in values of alpha NPV over the left-dorsal FC (?alpha-F3-NPV) and the medial FC (?alpha-Fz-NPV) induced by CSF tapping (cut-off value of ?alpha-F3-NPV + ?alpha-Fz-NPV = 0), could correctly identified “shunt responders” and “shunt nonresponders” with a positive predictive value of 100% (10/10) and a negative predictive value of 66% (2/3). In contrast, EEG power spectral analysis showed no function related changes in cortical activity at the frontal cortex before and after CSF tapping. These results indicate that the clinical changes in gait and response suppression induced by CSF tapping in iNPH patients manifest as NPV changes, particularly in the alpha band, rather than as EEG power changes. Our findings suggest that NAT analysis can detect CSF tapping-induced functional changes in cortical activity, in a way that no other neuroimaging methods have been able to do so far, and can predict clinical response to shunt operation in patients with iNPH. PMID:24273735

Aoki, Yasunori; Kazui, Hiroaki; Tanaka, Toshihisa; Ishii, Ryouhei; Wada, Tamiki; Ikeda, Shunichiro; Hata, Masahiro; Canuet, Leonides; Musha, Toshimitsu; Matsuzaki, Haruyasu; Imajo, Kaoru; Yoshiyama, Kenji; Yoshida, Tetsuhiko; Shimizu, Yoshiro; Nomura, Keiko; Iwase, Masao; Takeda, Masatoshi

2013-01-01

264

EEG asymmetry in borderline personality disorder and depression following rejection.  

PubMed

Borderline personality disorder (BPD) and major depressive disorder (MDD) share numerous features, including dysphoric affect, irritability, suicidality, and a heightened sensitivity to perceived interpersonal rejection. However, these disorders are associated with divergent profiles of reactivity to rejection: Individuals with MDD are more likely to respond with withdrawal and isolation, and those with BPD appear to respond with increased approach behaviors and greater hostility. Potential mechanisms underlying these divergent patterns of response have not been elaborated. The goal of the present study was to assess whether prefrontal cortical asymmetry is associated with these behavioral profiles. EEG alpha activity was recorded at baseline and after individuals with BPD, MDD and healthy controls (HCs) participated in a rejection task. Although no differences were found at baseline, results demonstrated that following rejection, individuals with BPD showed greater left cortical activation, consistent with approach motivation, whereas those with MDD showed greater right cortical activation, consistent with withdrawal motivation. HCs evidenced a more balanced cortical profile, as hypothesized. Although BPD and MDD are highly comorbid, are easily confused, and are phenomenologically similar in a number of ways, individuals with these two disorders respond in very different ways to perceived rejection. PMID:24364503

Beeney, Joseph E; Levy, Kenneth N; Gatzke-Kopp, Lisa M; Hallquist, Michael N

2014-04-01

265

Preliteracy signatures of poor-reading abilities in resting-state EEG  

PubMed Central

The hereditary character of dyslexia suggests the presence of putative underlying neural anomalies already in preliterate age. Here, we investigated whether early neurophysiological correlates of future reading difficulties—a hallmark of dyslexia—could be identified in the resting-state EEG of preliterate children. The children in this study were recruited at birth and classified on the basis of parents' performance on reading tests to be at-risk of becoming poor readers (n = 48) or not (n = 14). Eyes-open rest EEG was measured at the age of 3 years, and the at-risk children were divided into fluent readers (n = 24) and non-fluent readers (n = 24) after reading assessment at their third grade of school. We found that fluent readers and non-fluent readers differed in normalized spectral amplitude. Non-fluent readers were characterized by lower amplitude in the delta-1 frequency band (0.5–2 Hz) and higher amplitude in the alpha-1 band (6–8 Hz) in multiple scalp regions compared to control and at-risk fluent readers. Interestingly, across groups these EEG biomarkers correlated with several behavioral test scores measured in the third grade. Specifically, the performance on reading fluency, phonological and orthographic tasks and rapid automatized naming task correlated positively with delta-1 and negatively with alpha-1. Together, our results suggest that combining family-risk status, neurophysiological testing and behavioral test scores in a longitudinal setting may help uncover physiological mechanisms implicated with neurodevelopmental disorders such as the predisposition to reading disabilities.

Schiavone, Giuseppina; Linkenkaer-Hansen, Klaus; Maurits, Natasha M.; Plakas, Anna; Maassen, Ben A. M.; Mansvelder, Huibert D.; van der Leij, Aryan; van Zuijen, Titia L.

2014-01-01

266

Brain activity in predictive sensorimotor control for landings: an EEG pilot study.  

PubMed

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

2013-12-01

267

Detecting epileptic seizures in long-term human EEG: a new approach to automatic online and real-time detection and classification of polymorphic seizure patterns.  

PubMed

Epileptic seizures can cause a variety of temporary changes in perception and behavior. In the human EEG they are reflected by multiple ictal patterns, where epileptic seizures typically become apparent as characteristic, usually rhythmic signals, often coinciding with or even preceding the earliest observable changes in behavior. Their detection at the earliest observable onset of ictal patterns in the EEG can, thus, be used to start more-detailed diagnostic procedures during seizures and to differentiate epileptic seizures from other conditions with seizure-like symptoms. Recently, warning and intervention systems triggered by the detection of ictal EEG patterns have attracted increasing interest. Since the workload involved in the detection of seizures by human experts is quite formidable, several attempts have been made to develop automatic seizure detection systems. So far, however, none of these found widespread application. Here, we present a novel procedure for generic, online, and real-time automatic detection of multimorphologic ictal-patterns in the human long-term EEG and its validation in continuous, routine clinical EEG recordings from 57 patients with a duration of approximately 43 hours and additional 1,360 hours of seizure-free EEG data for the estimation of the false alarm rates. We analyzed 91 seizures (37 focal, 54 secondarily generalized) representing the six most common ictal morphologies (alpha, beta, theta, and delta- rhythmic activity, amplitude depression, and polyspikes). We found that taking the seizure morphology into account plays a crucial role in increasing the detection performance of the system. Moreover, besides enabling a reliable (mean false alarm rate<0.5/h, for specific ictal morphologies<0.25/h), early and accurate detection (average correct detection rate>96%) within the first few seconds of ictal patterns in the EEG, this procedure facilitates the automatic categorization of the prevalent seizure morphologies without the necessity to adapt the proposed system to specific patients. PMID:18469727

Meier, Ralph; Dittrich, Heike; Schulze-Bonhage, Andreas; Aertsen, Ad

2008-06-01

268

Standardized computer-based organized reporting of EEG: SCORE.  

PubMed

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. PMID:23506075

Beniczky, Sándor; Aurlien, Harald; Brøgger, Jan C; Fuglsang-Frederiksen, Anders; Martins-da-Silva, António; Trinka, Eugen; Visser, Gerhard; Rubboli, Guido; Hjalgrim, Helle; Stefan, Hermann; Rosén, Ingmar; Zarubova, Jana; Dobesberger, Judith; Alving, Jørgen; Andersen, Kjeld V; Fabricius, Martin; Atkins, Mary D; Neufeld, Miri; Plouin, Perrine; Marusic, Petr; Pressler, Ronit; Mameniskiene, Ruta; Hopfengärtner, Rüdiger; van Emde Boas, Walter; Wolf, Peter

2013-06-01

269

Alpha rhythms: noise, dynamics and models.  

PubMed

Alpha rhythms appear as sinusoidal-like oscillations in the electroencephalogram (EEG) within the frequency range 8-12 Hz that waxe and wane in a more or less irregular way. The irregularity may have various origins. It may be due to noise or the oscillations may have an intrinsic irregular character, e.g. they may be generated by chaotic processes [Jansen (1991) Quantitative analysis of electroencephalograms: is there chaos in the future? Int. J. Biomed. Comput., 27: 95-123; Pradham, N. and Dutt, D.N. (1993) A nonlinear perspective in understanding the neurodynamics of EEG. Comput. Biol. Med., 23: 425-442; Pritchard et al. (1995) Dimensional analysis of resting human EEG II: Surrogate-data testing indicates nonlinearily but not low-dimensional chaos. Psychophysiology. 32: 486]. The term noise is often used in neurophysiology with different connotations as pointed out by Bullock (1990), either meaning an unwanted signal from the point of view of the receiver of a message, or a signal with intrinsic random fluctuations, i.e. with a stochastic character. Here we consider noise in this sense, as random or quasi-random neural activity. In this overview, we concentrate on the question of whether alpha rhythms should be considered generated in neuronal networks (1) as forms of filtered noise, (2) as deterministic oscillations influenced by noise or (3) as the result of chaotic dynamics. A clear answer to this question can have theoretical value because it may lead to a general model of the generation of this important EEG signal. Such a model, of course, would be a macroscopic one, since it would primarily account for the properties of the alpha rhythms at the neuronal network level. A translation of these properties to the microscopic, i.e. neuronal, level will not be easy to achieve without more direct knowledge of the membrane and synaptic basic properties of the neurons involved. Here we consider the question formulated above by presenting some relevant experimental evidence and theoretical arguments. The consideration whether alpha rhythms may have noise or chaotic sources implies examining how and where such sources can occur in the neuronal networks of the brain. Therefore we present, first, some basic data regarding the possible origin of noise and of chaos in neuronal networks. Second, the signal analysis methods that have to be applied in order to discriminate between filtered noise activities and chaotic oscillations are introduced. Third, the implications of these signal analyses regarding the possible answer to the initial question are discussed. PMID:9203006

Lopes da Silva, F H; Pijn, J P; Velis, D; Nijssen, P C

1997-06-01

270

Alpha Thalassemia  

MedlinePLUS

... an apparently normal individual has a child with hemoglobin H disease or alpha thalassemia minor. It can ... pregnancy that their child will be born with hemoglobin H disease in which three of the four ...

271

Absent posterior alpha rhythm: An indirect indicator of seizure disorder?  

PubMed Central

Hypothesis: Absence of normal posterior alpha rhythm is an indirect indicator of seizure disorder. Materials and Methods: Study group consists of 116 child and adolescent patients in the age range of 5-17 years, with established history of seizure disorder. Follow-up cases of seizure disorder formed first comparison group, patients with a history of pseudo-seizures formed second comparison group and patients with a history of headache formed the third comparison group. Results: In significant 48.3% (56) patients within the study group there was no visible alpha rhythm. Whereas, this absent alpha rhythm criteria was seen in only 11.2% (4) patients in first and 15% (8) patients in second and in only 6.1% (2) patients in third comparison groups. Discussion: Absent alpha rhythm- a criterion seems to have a certain amount of specificity for electroencephalograms (EEGs) with seizure disorder patients. Presence of seizure activity and absence of alpha activity in EEG significantly correlated to each other (Significant at < 0.01 level). Absent alpha rhythm appears to be a state marker rather than a trait marker of seizure disorder. PMID:24574560

Aich, Tapas Kumar

2014-01-01

272

Pattern changes of EEG oscillations and BOLD signals associated with temporal lobe epilepsy as revealed by a working memory task  

PubMed Central

Background It is known that the abnormal neural activity in epilepsy may be associated to the reorganization of neural circuits and brain plasticity in various ways. On that basis, we hypothesized that changes in neuronal circuitry due to epilepsy could lead to measurable variations in patterns of both EEG and BOLD signals in patients performing some cognitive task as compared to what would be obtained in normal condition. Thus, the aim of this study was to compare the cerebral areas involved in EEG oscillations versus fMRI signal patterns during a working memory (WM) task in normal controls and patients with refractory mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS). The study included six patients with left MTLE-HS (left-HS group) and seven normal controls (control group) matched to the patients by age and educational level, both groups undergoing a blocked design paradigm based on Sternberg test during separated EEG and fMRI sessions. This test consisted of encoding and maintenance of a variable number of consonant letters on WM. Results EEG analysis for the encoding period revealed the presence of theta and alpha oscillations in the frontal and parietal areas, respectively. Likewise, fMRI showed the co-occurrence of positive and negative BOLD signals in both brain regions. As for the maintenance period, whereas EEG analysis revealed disappearance of theta oscillation, fMRI showed decrease of positive BOLD in frontal area and increase of negative BOLD in the posterior part of the brain. Conclusions Generally speaking, these patterns of electrophysiological and hemodynamic signals were observed for both control and left-HS groups. However, the data also revealed remarkable differences between these groups that are consistent with the hypothesis of reorganization of brain circuitry associated with epilepsy. PMID:24766708

2014-01-01

273

EEG spatio-spectral mapping during video game play  

Microsoft Academic Search

The aim of this study was to examine brain dynamics during video game play by means of electrophysiological brain mapping. We have conducted a pilot experimental study on healthy young human subjects during video game play. High resolution EEG (64-ch or 128-ch) was obtained to detect and monitor electroencephalograms (EEG) on the scalp of the subjects. Electrophysiological recordings were made

E. J. He; H. Yuan; L. Yang; C. Sheikholeslami; B. He

2008-01-01

274

An artificial intelligence approach to classify and analyse EEG traces  

Microsoft Academic Search

We present a fully automatic system for the classification and analysis of adult electroencephalograms (EEGs). The system is based on an artificial neural network which classifies the single epochs of trace, and on an Expert System (ES) which studies the time and space correlation among the outputs of the neural network; compiling a final report. On the last 2000 EEGs

C. Castellaro; G. Favaro; A. Castellaro; A. Casagrande; S. Castellaro; D. V. Puthenparampil; C. Fattorello Salimbeni

2002-01-01

275

EEG Patterns Related to Cognitive Tasks of Varying Complexity.  

ERIC Educational Resources Information Center

A study was conducted that attempted to show changes in electroencephalographic (EEG) patterns (identified using topographic EEG mapping) when children were required to perform the relatively simple task of button pressing during an eyes-open baseline session of low cognitive demand and a complex reaction time (RT) task of high cognitive demand.…

Dunn, Denise A.; And Others

276

EEG CLASSIFICATION OF MILD AND SEVERE ALZHEIMER'S DISEASE USING PARALLEL  

E-print Network

METHOD PARAFAC Decomposition of Spectral-Spatial Characteristics of EEG Time Series Charles of the disease, might render the study difficult when undertaken subject-by- subject. In that case, a multiChapter 1 EEG CLASSIFICATION OF MILD AND SEVERE ALZHEIMER'S DISEASE USING PARALLEL FACTOR ANALYSIS

Vialatte, François

277

PEDIATRIC ANESTHESIA MONITORING WITH THE HELP OF EEG AND ECG  

E-print Network

PEDIATRIC ANESTHESIA MONITORING WITH THE HELP OF EEG AND ECG L. Senhadji, G. Carrault, H. Gauvrit AND ECG L. Senhadji, G. Carrault, H. Gauvrit, E. Wodey, P. Pladys, F. Carré Correspondance : Laboratoire of anesthesia during surgery. Particular variables are derived from EEG and ECG signals and are correlated

Paris-Sud XI, Université de

278

CONSTRAINED ICA FOR SEIZURE ONSET ANALYSIS IN THE EEG  

Microsoft Academic Search

The extraction of epileptic seizure waveform from the electroencephalogram (EEG) using Independent Component Analysis (ICA) was demonstrated by James and Lowe. A recent variation, Constrained ICA, allows a supplied reference signal to select a single component to be extracted. We show how this algorithm can be applied to the problem of seizure waveform extraction from EEG signals prior to the

Oliver Gibson; Christopher James

279

Enhanced dynamic complexity in the human EEG during creative thinking  

Microsoft Academic Search

This study shows that divergent thinking, considered the general process underlying creative production, can be distinguished from convergent, analytical thought based on the dimensional complexity of ongoing electroencephalographic (EEG) activity. EEG complexity over the central and posterior cortex was higher while subjects solved tasks of divergent than convergent thinking, and also higher than during mental relaxation. Over the frontal cortex,

Matthias Mölle; Lisa Marshall; Werner Lutzenberger; Reinhard Pietrowsky; Horst L. Fehm; Jan Born

1996-01-01

280

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 coherence, occasional “growth spurts” are observed which coincide with periods of discontinuous development in cognition. Discontinuous development may reflect changes in the genetic architecture of a trait over time, for instance, by the emergence of new

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

2001-01-01

281

Classification of movement EEG with local discriminant bases  

Microsoft Academic Search

We use local discriminant bases and linear discriminant analysis to classify EEG of left and right hand movement execution and imagination. The local discriminant bases adaptively segment and extract features from real and imagined movement EEG (2003 BCI competition) using cosine packets and Kullback-Leibler, Euclidean and Hellinger class separability (CS) criteria. We also tried principal component analysis (PCA) as another

Nuri Firat Ince; Ahmed Tewfik; Sami Arica

2005-01-01

282

Continuous EEG Monitoring in the Intensive Care Unit  

Microsoft Academic Search

Summary: Continuous EEG (CEEG) monitoring allows un- interrupted assessment of cerebral cortical activity with good spatial resolution and excellent temporal resolution. Thus, this procedure provides a means of constantly assessing brain func- tion in critically ill obtunded and comatose patients. Recent advances in digital EEG acquisition, storage, quantitative analysis, and transmission have made CEEG monitoring in the intensive care unit

2002-01-01

283

Implementation of an offline chaos-based EEG encryption software  

Microsoft Academic Search

In the paper, we use Microsoft visual studio development kit and C# programming to implement a chaos-based electroencephalogram (EEG) encryption software. A chaos logic map, and initial value of the chaos logic map are used to generate level I chaos-based EEG encryption bit streams. A chaos logic map, initial value, a bifurcation parameter of the chaos logic map, and two

Chin-Feng Lin; Shun-Han Shih; Jin-De Zhu; Sang-Hung Lee

2012-01-01

284

Emotion recognition from EEG using higher order crossings  

Microsoft Academic Search

Electroencephalogram (EEG)-based emotion recognition is a relatively new field in the affective computing area with challenging issues regarding the induction of the emotional states and the extraction of the features in order to achieve optimum classification performance. In this paper, a novel emotion evocation and EEG-based feature extraction technique is presented. In particular, the mirror neuron system concept was adapted

Panagiotis C. Petrantonakis; Leontios J. Hadjileontiadis

2010-01-01

285

Analysis of EEG signals during acupuncture using spectral analysis techniques  

Microsoft Academic Search

Power spectral analysis is a traditional method used for EEG analyzing. In this paper, Welch method was used to process the signals obtained from a carefully designed acupuncture experiment. The main objective of this work is to find the effect of acupuncture on brain. A protocol composed of three different manipulations has been designed to acquire the EEG signals using

Nuo Li; Jiang Wang; Bin Deng; Yan-Qiu Che

2010-01-01

286

Analysis of EEG signals during acupuncture using spectral analysis techniques  

Microsoft Academic Search

Power spectral analysis is a traditional method used for EEG analysing. In this paper, Welch method was used to process the signals obtained from a carefully designed acupuncture experiment. The main objective of this work is to find the effect of acupuncture on brain. A protocol composed of three different manipulations has been designed to acquire the EEG signals using

Nuo Li; Y. K. Wong; W. L. Chan; K. M. Tsang

2010-01-01

287

Intuitionistic fuzzy approach in enhancing image of flat EEG  

NASA Astrophysics Data System (ADS)

Image enhancement is a process to improve the quality of an image which mainly due to presence of noise. It is an initial step in medical imaging. Fuzzy approach has been used widely in the area of image processing. However, in this paper, image enhancement of Flat EEG (fEEG) during epileptic seizures using intuitionistic fuzzy set (IFS) is presented and compared.

Zenian, Suzelawati; Ahmad, Tahir; Idris, Amidora

2014-07-01

288

Classification of spontaneous EEG signals in migraine  

NASA Astrophysics Data System (ADS)

We set up a classification system able to detect patients affected by migraine without aura, through the analysis of their spontaneous EEG patterns. First, the signals are characterized by means of wavelet-based features, than a supervised neural network is used to classify the multichannel data. For the feature extraction, scale-dependent and scale-independent methods are considered with a variety of wavelet functions. Both the approaches provide very high and almost comparable classification performances. A complete separation of the two groups is obtained when the data are plotted in the plane spanned by two suitable neural outputs.

Bellotti, R.; De Carlo, F.; de Tommaso, M.; Lucente, M.

2007-08-01

289

Time perception at different EEG-vigilance levels  

PubMed Central

Background Human time perception is influenced by various factors such as attention and drowsiness. Nevertheless, the impact of cerebral vigilance fluctuations on temporal perception has not been sufficiently explored. We assumed that the state of vigilance ascertained by electroencephalography (EEG) during the perception of a given auditory rhythm would influence its reproduction. Thus, we hypothesised that the re-tapping interval length and the accuracy of reproduction performance would vary depending on the state of vigilance determined by EEG. Methods 12 female and 9 male subjects ranging from 21 to 38 years (M = 25.52, SD = 3.75) participated in a test paradigm comprising a) a resting EEG for the determination of vigilance while an auditory rhythm was presented, b) a short activity of the proband to be sure of sufficient alertness, and c) a tapping task to reproduce the presented rhythm. Vigilance states of three consecutive 1-sec-EEG-segments of the resting EEG before the reproduction phase were classified using the Vigilance Algorithm Leipzig (VIGALL). Results and discussion Reproduction accuracy was more precise after high EEG-vigilance stages. Thus, the subjects’ mean deviation from the given rhythm was lower (t(17) = ?2.733, p < 0.05) after high vigilance stage A (MW = 0.046, SD = 0.049) than after low vigilance stage B (MW = 0.065, SD = 0.067). The re-tapping-length was significantly shorter (t(17) = ?2.190, p < 0.05) for reproduction phases following high EEG-vigilance stage A compared to the lower EEG-vigilance stage B. Conclusion These findings support the hypothesis of a varying time perception and of speed alterations of the internal clock after different states of EEG-vigilance, which were automatically classified by VIGALL. Thus, alterations of cognitive processing may be assessable by specific EEG-patterns. PMID:22998925

2012-01-01

290

Power changes of EEG signals associated with muscle fatigue: the root mean square analysis of EEG bands  

Microsoft Academic Search

The paper reports a research conducted to determine changes in the electrical activity of the contralateral motor cortex of the brain that drives the maximum voluntary contraction (MVC) of the right adductor pollicis muscle (APM) after fatigue. The power changes of EEG signals after muscle fatigue were computed. In twenty-five subjects, EEG signals from the left motor cortical area (C3,

A. A. Abdul-latif; I. Cosic; D. K. Kumar; B. Polus; C. Da Costa

2004-01-01

291

Power changes of EEG signals associated with muscle fatigue: The Root Mean Square analysis of EEG bands  

Microsoft Academic Search

This paper reports a research conducted to determine the changes in the electrical activity of the contralateral motor cortex of the brain that drives the maximum voluntary contraction (MVC) of right Adductor Pollicis muscle (APM) after fatigue. For this aim, the power changes of EEG signals after muscle fatigue were computed. EEG signals from the left motor cortical area (C3,

Ali A. Abdul-latif; Irena Cosic; Dinesh K. Kumar; Barbara Polus; Cliff Da Costa

2008-01-01

292

Upper alpha ERD and absolute power: their meaning for memory performance  

Microsoft Academic Search

A variety of studies have shown that EEG alpha activity in the upper frequency range is associated with different types of cognitive processes, memory performance, perceptual performance and intelligence, but in strikingly different ways. For semantic memory performance we have found that resting or reference power is positively associated with performance, whereas during actual processing of the task, small power

Wolfgang Klimesch; Michael Doppelmayr; Simon Hanslmayr

2006-01-01

293

Alpha Oscillations in Response to Affective and Cigarette-Related Stimuli in Smokers  

PubMed Central

Introduction: The presence of cigarette-related cues has been associated with smoking relapse. These cues are believed to activate brain mechanisms underlying emotion, attention, and memory. Electroencephalography (EEG) alpha desynchronization (i.e., reduction in alpha power) has been suggested to index the engagement of these mechanisms. Analyzing EEG alpha desynchronization in response to affective and smoking cues might improve our understanding of how smokers process these cues, and the potential impact of this processing on relapse. Methods: Before the start of a medication-assisted cessation attempt, we recorded EEG from 179 smokers during the presentation of neutral, pleasant, unpleasant, and cigarette-related pictures. Wavelet analysis was used to extract EEG alpha oscillations (8–12 Hz) in response to these pictures. Alpha oscillations were analyzed as a function of picture valence and arousal dimensions. Results: Emotional and cigarette-related stimuli induced a higher level of alpha desynchronization (i.e., less power in the alpha frequency band) than neutral stimuli. In addition, the level of alpha desynchronization induced by cigarette-related stimuli was similar to that induced by highly arousing stimuli (i.e., erotica and mutilations). Conclusions: These results suggest that, for smokers, cigarette-related cues are motivationally significant stimuli that may engage emotional, attentional, and memory-related neural mechanisms at a level comparable to that seen in response to highly arousing stimuli. This finding suggests that activation of emotional, attentional, and memory-related brain mechanisms may be an important contributor to cue-induced smoking relapse. PMID:23060019

2013-01-01

294

Wireless Non-contact EEG/ECG Electrodes for Body Sensor Networks  

E-print Network

Wireless Non-contact EEG/ECG Electrodes for Body Sensor Networks Yu M. Chi and Gert Cauwenberghs University of California, San Diego La Jolla, CA 92093 Abstract--A wireless EEG/ECG system using non transmits EEG/ECG telemetry to a computer for storage and processing. Index Terms--ECG, EEG, Body Sensor

Cauwenberghs, Gert

295

Real-Time Seizure Detection Based on EEG and ECG Fused Features Using Gabor Functions  

Microsoft Academic Search

using the scalp electroencephalogram (EEG) to detect seizure onsets that are not associated with rhythmic EEG activity is challenging. In this paper, we illustrate how supplementing the extracted information from the scalp EEG with the extracted information from electrocardiogram (ECG) can improve the detection of these types of seizures. In this scheme, spectral and spatial features are extracted from EEG

Saadat Nasehi; Hossein Pourghassem

2011-01-01

296

Evidence of a Faster Posterior Dominant EEG Rhythm in Children with Autism  

ERIC Educational Resources Information Center

Multiple electroencephalography (EEG) abnormalities have been associated with autism. In the course of clinical work, we have observed a posterior dominant EEG rhythm at higher frequency in children with autism. To test this observation, 56 EEG tracings of children with autism were compared to the EEGs of age-matched controls. Children with autism…

Gregory, Michael D.; Mandelbaum, David E.

2012-01-01

297

Interregional cortical interactions at different stages of natural sleep and the hypnotic state: EEG evidence  

Microsoft Academic Search

The characteristic patterns of EEG spatial organization at different stages of natural sleep and the hypnotic state were studied in 26 volunteers aged 18–22 years. EEGs were recorded using 12 monopolar leads, and EEG cross-correlation coefficient matrices were calculated for consecutive epochs (4 and 8 s). Matrices averaged for each state were treated using factor analysis. The EEG correlation matrices

A. N. Shepovalnikov; M. N. Tsitseroshin; V. P. Rozhkov; E. I. Galperina; L. G. Zaitseva; R. A. Shepovalnikov

2005-01-01

298

EEG microstates during resting represent personality differences.  

PubMed

We investigated the spontaneous brain electric activity of 13 skeptics and 16 believers in paranormal phenomena; they were university students assessed with a self-report scale about paranormal beliefs. 33-channel EEG recordings during no-task resting were processed as sequences of momentary potential distribution maps. Based on the maps at peak times of Global Field Power, the sequences were parsed into segments of quasi-stable potential distribution, the 'microstates'. The microstates were clustered into four classes of map topographies (A-D). Analysis of the microstate parameters time coverage, occurrence frequency and duration as well as the temporal sequence (syntax) of the microstate classes revealed significant differences: Believers had a higher coverage and occurrence of class B, tended to decreased coverage and occurrence of class C, and showed a predominant sequence of microstate concatenations from A to C to B to A that was reversed in skeptics (A to B to C to A). Microstates of different topographies, putative "atoms of thought", are hypothesized to represent different types of information processing.The study demonstrates that personality differences can be detected in resting EEG microstate parameters and microstate syntax. Microstate analysis yielded no conclusive evidence for the hypothesized relation between paranormal belief and schizophrenia. PMID:21644026

Schlegel, Felix; Lehmann, Dietrich; Faber, Pascal L; Milz, Patricia; Gianotti, Lorena R R

2012-01-01

299

Spatiotemporal Analysis of Multichannel EEG: CARTOOL  

PubMed Central

This paper describes methods to analyze the brain's electric fields recorded with multichannel Electroencephalogram (EEG) and demonstrates their implementation in the software CARTOOL. It focuses on the analysis of the spatial properties of these fields and on quantitative assessment of changes of field topographies across time, experimental conditions, or populations. Topographic analyses are advantageous because they are reference independents and thus render statistically unambiguous results. Neurophysiologically, differences in topography directly indicate changes in the configuration of the active neuronal sources in the brain. We describe global measures of field strength and field similarities, temporal segmentation based on topographic variations, topographic analysis in the frequency domain, topographic statistical analysis, and source imaging based on distributed inverse solutions. All analysis methods are implemented in a freely available academic software package called CARTOOL. Besides providing these analysis tools, CARTOOL is particularly designed to visualize the data and the analysis results using 3-dimensional display routines that allow rapid manipulation and animation of 3D images. CARTOOL therefore is a helpful tool for researchers as well as for clinicians to interpret multichannel EEG and evoked potentials in a global, comprehensive, and unambiguous way. PMID:21253358

Brunet, Denis; Murray, Micah M.; Michel, Christoph M.

2011-01-01

300

Evaluation of partial epilepsy in Iran: role of video-EEG, EEG, and MRI with epilepsy protocol  

PubMed Central

Background We evaluated the diagnostic value of Electroencephalography (EEG), video-EEG monitoring (VEM) and Magnetic resonance imaging (MRI) of the brain with epilepsy protocol in patients with complex partial epilepsy. Methods Forty-two consecutive patients underwent complete neurological examination, EEG, and MRI with a modified epilepsy protocol. A subset of these patients (n = 29) also underwent VEM. Data were presented using descriptive statistics and were analyzed using Chi square and McNemar tests. Results Twenty-four women and eighteen men entered the study. The mean (±SD) age for patients, was 25.2(±10.1) and mean (±SD) age at onset was 10.9(±8.1). All patients had abnormal ictal or interictal EEG. Fifteen patients had normal MRI. Temporal lobe involvement was the most common involvement in both EEG (27 patients) and MRI (14 patients). Interictal EEG was abnormal in 81% of patients which showed epileptiform discharges in about half of the cases. In half of patients who had lateralized finding on MRI, site of the lesion was congruent between MRI and interictal EEG. Thirty-six patients had symptoms suggesting a specific lobe, of which interictal EEG was able to show the concordant lobe in 22 (61%) patients. McNemar test showed superiority of EEG over MRI in correct diagnosis of the involved lobe based on the clinical manifestations (P < 0.01). Conclusion In our setting, both ictal and interictal EEG perform better than MRI in evaluating complex partial epilepsy. In addition, combination of these tools may increase the yield of showing abnormality to near 100% in patients with complex partial epilepsy. PMID:24250836

Tafakhori, Abbas; Aghamollaii, Vajiheh; Modabbernia, Amir Hossein; Omrani, Hossein Ali Ghelichnia; Harirchian, Mohammad Hossein; Mousavi, Mahsa; Faraji, Parastoo

2011-01-01

301

Higher-Order Spectrum in Understanding Nonlinearity in EEG Rhythms  

PubMed Central

The fundamental nature of the brain's electrical activities recorded as electroencephalogram (EEG) remains unknown. Linear stochastic models and spectral estimates are the most common methods for the analysis of EEG because of their robustness, simplicity of interpretation, and apparent association with rhythmic behavioral patterns in nature. In this paper, we extend the use of higher-order spectrum in order to indicate the hidden characteristics of EEG signals that simply do not arise from random processes. The higher-order spectrum is an extension Fourier spectrum that uses higher moments for spectral estimates. This essentially nullifies all Gaussian random effects, therefore, can reveal non-Gaussian and nonlinear characteristics in the complex patterns of EEG time series. The paper demonstrates the distinguishing features of bispectral analysis for chaotic systems, filtered noises, and normal background EEG activity. The bispectrum analysis detects nonlinear interactions; however, it does not quantify the coupling strength. The squared bicoherence in the nonredundant region has been estimated to demonstrate nonlinear coupling. The bicoherence values are minimal for white Gaussian noises (WGNs) and filtered noises. Higher bicoherence values in chaotic time series and normal background EEG activities are indicative of nonlinear coupling in these systems. The paper shows utility of bispectral methods as an analytical tool in understanding neural process underlying human EEG patterns. PMID:22400046

Pradhan, Cauchy; Jena, Susant K.; Nadar, Sreenivasan R.; Pradhan, N.

2012-01-01

302

Wireless and wearable EEG system for evaluating driver vigilance.  

PubMed

Brain activity associated with attention sustained on the task of safe driving has received considerable attention recently in many neurophysiological studies. Those investigations have also accurately estimated shifts in drivers' levels of arousal, fatigue, and vigilance, as evidenced by variations in their task performance, by evaluating electroencephalographic (EEG) changes. However, monitoring the neurophysiological activities of automobile drivers poses a major measurement challenge when using a laboratory-oriented biosensor technology. This work presents a novel dry EEG sensor based mobile wireless EEG system (referred to herein as Mindo) to monitor in real time a driver's vigilance status in order to link the fluctuation of driving performance with changes in brain activities. The proposed Mindo system incorporates the use of a wireless and wearable EEG device to record EEG signals from hairy regions of the driver conveniently. Additionally, the proposed system can process EEG recordings and translate them into the vigilance level. The study compares the system performance between different regression models. Moreover, the proposed system is implemented using JAVA programming language as a mobile application for online analysis. A case study involving 15 study participants assigned a 90 min sustained-attention driving task in an immersive virtual driving environment demonstrates the reliability of the proposed system. Consistent with previous studies, power spectral analysis results confirm that the EEG activities correlate well with the variations in vigilance. Furthermore, the proposed system demonstrated the feasibility of predicting the driver's vigilance in real time. PMID:24860041

Lin, Chin-Teng; Chuang, Chun-Hsiang; Huang, Chih-Sheng; Tsai, Shu-Fang; Lu, Shao-Wei; Chen, Yen-Hsuan; Ko, Li-Wei

2014-04-01

303

EEG model and location in brain when enjoying music.  

PubMed

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 differences have been found between them. And the character of EEG has a little differences when the subjects enjoyed different rhythm music. The character of EEG is 30 Hz when the subjects enjoyed Skating Waltz, the height of wave crest is about 200; the character of EEG is 32 Hz when the subjects enjoyed Radetzy-March, the height of wave crest is about 300-500; the character of EEG is 28 Hz and 38 Hz when the subjects enjoyed Disco music, the height of wave crest is about 200. Then using the software of ASA 3 Course designed by ANT company of Germany, the location in brain was confirmed when a person had excited. The region of the location in brain when a person was excited was focused in the area of the middle abdomen in the pons' side. PMID:17282795

Lu, Huisheng; Wang, Mingshi; Yu, Hongqiang

2005-01-01

304

Usability of four commercially-oriented EEG systems.  

PubMed

Electroencephalography (EEG) holds promise as a neuroimaging technology that can be used to understand how the human brain functions in real-world, operational settings while individuals move freely in perceptually-rich environments. In recent years, several EEG systems have been developed that aim to increase the usability of the neuroimaging technology in real-world settings. Here, the usability of three wireless EEG systems from different companies are compared to a conventional wired EEG system, BioSemi's ActiveTwo, which serves as an established laboratory-grade 'gold standard' baseline. The wireless systems compared include Advanced Brain Monitoring's B-Alert X10, Emotiv Systems' EPOC and the 2009 version of QUASAR's Dry Sensor Interface 10-20. The design of each wireless system is discussed in relation to its impact on the system's usability as a potential real-world neuroimaging system. Evaluations are based on having participants complete a series of cognitive tasks while wearing each of the EEG acquisition systems. This report focuses on the system design, usability factors and participant comfort issues that arise during the experimental sessions. In particular, the EEG systems are assessed on five design elements: adaptability of the system for differing head sizes, subject comfort and preference, variance in scalp locations for the recording electrodes, stability of the electrical connection between the scalp and electrode, and timing integration between the EEG system, the stimulus presentation computer and other external events. PMID:24980915

David Hairston, W; Whitaker, Keith W; Ries, Anthony J; Vettel, Jean M; Cortney Bradford, J; Kerick, Scott E; McDowell, Kaleb

2014-08-01

305

Usability of four commercially-oriented EEG systems  

NASA Astrophysics Data System (ADS)

Electroencephalography (EEG) holds promise as a neuroimaging technology that can be used to understand how the human brain functions in real-world, operational settings while individuals move freely in perceptually-rich environments. In recent years, several EEG systems have been developed that aim to increase the usability of the neuroimaging technology in real-world settings. Here, the usability of three wireless EEG systems from different companies are compared to a conventional wired EEG system, BioSemi’s ActiveTwo, which serves as an established laboratory-grade ‘gold standard’ baseline. The wireless systems compared include Advanced Brain Monitoring’s B-Alert X10, Emotiv Systems’ EPOC and the 2009 version of QUASAR’s Dry Sensor Interface 10-20. The design of each wireless system is discussed in relation to its impact on the system’s usability as a potential real-world neuroimaging system. Evaluations are based on having participants complete a series of cognitive tasks while wearing each of the EEG acquisition systems. This report focuses on the system design, usability factors and participant comfort issues that arise during the experimental sessions. In particular, the EEG systems are assessed on five design elements: adaptability of the system for differing head sizes, subject comfort and preference, variance in scalp locations for the recording electrodes, stability of the electrical connection between the scalp and electrode, and timing integration between the EEG system, the stimulus presentation computer and other external events.

Hairston, W. David; Whitaker, Keith W.; Ries, Anthony J.; Vettel, Jean M.; Cortney Bradford, J.; Kerick, Scott E.; McDowell, Kaleb

2014-08-01

306

The EEG signal: a window on the cortical brain activity.  

PubMed

The accurate assessment of the depth of anesthesia, allowing a more accurate adaptation of the doses of hypnotics, is an important end point for the anesthesiologist. It is a particularly crucial issue in pediatric anesthesia, in the context of the recent controversies about the potential neurological consequences of the main anesthetic drugs on the developing brain. The electroencephalogram signal reflects the electrical activity of the neurons in the cerebral cortex. It is thus the key to assessment of the level of hypnosis. Beyond visual analysis, several monitoring devices allow an automated treatment of the electroencephalographic (EEG) signal, combining time and frequency domain analysis. Each of these monitors focuses on a specific combination of characteristics of the signal and provides the clinician with useful information that remains, however, partial. For a comprehensive approach of the EEG-derived indices, the main features of the normal EEG, in adults and children, will be presented in the awake state and during sleep. Age-related modifications accompanying cerebral maturation during infancy and childhood will be detailed. Then, this review will provide an update on how anesthetic drugs, particularly hypnotics, influence the EEG signal, and how the main available monitors analyze these drug-induced modifications. The relationships between pain, memory, and the EEG will be discussed. Finally, this review will focus on some specific EEG features such as the electrical epileptoid activity observed under sevoflurane anesthesia. The EEG signal is the best window we have on cortical brain activity and provides a fair pharmacodynamic feedback of the effects of hypnotics. However, the cortex is only one of several targets of anesthesia. Hypnotics and opiates, have also subcortical primary targets, and the EEG performances in the evaluation or prediction of nociception are poor. Monitoring subcortical structures in combination with the EEG might in the future allow a better evaluation and a more precise adaptation of balanced anesthesia. PMID:22594406

Constant, Isabelle; Sabourdin, Nada

2012-06-01

307

Prospects for Clinical Applications of Transcranial Magnetic Stimulation and Real-Time EEG in Epilepsy  

Microsoft Academic Search

Recent advances in methods for transcranial magnetic stimulation (TMS) enable its coupling to real-time EEG (TMS-EEG). Although\\u000a TMS-EEG is applied largely in neurophysiology research, there are prospects for its use in clinical TMS practice, particularly\\u000a in epilepsy where EEG is already in wide use, and where TMS is emerging as a diagnostic and therapeutic tool. In diagnostic\\u000a applications, TMS-EEG may

Alexander Rotenberg

2010-01-01

308

Fractal dimension of EEG activity senses neuronal impairment in acute stroke.  

PubMed

The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD's ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4-10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures' activities in stroke recovery. PMID:24967904

Zappasodi, Filippo; Olejarczyk, Elzbieta; Marzetti, Laura; Assenza, Giovanni; Pizzella, Vittorio; Tecchio, Franca

2014-01-01

309

Wireless brain-machine interface using EEG and EOG: brain wave classification and robot control  

NASA Astrophysics Data System (ADS)

A brain-machine interface (BMI) links a user's brain activity directly to an external device. It enables a person to control devices using only thought. Hence, it has gained significant interest in the design of assistive devices and systems for people with disabilities. In addition, BMI has also been proposed to replace humans with robots in the performance of dangerous tasks like explosives handling/diffusing, hazardous materials handling, fire fighting etc. There are mainly two types of BMI based on the measurement method of brain activity; invasive and non-invasive. Invasive BMI can provide pristine signals but it is expensive and surgery may lead to undesirable side effects. Recent advances in non-invasive BMI have opened the possibility of generating robust control signals from noisy brain activity signals like EEG and EOG. A practical implementation of a non-invasive BMI such as robot control requires: acquisition of brain signals with a robust wearable unit, noise filtering and signal processing, identification and extraction of relevant brain wave features and finally, an algorithm to determine control signals based on the wave features. In this work, we developed a wireless brain-machine interface with a small platform and established a BMI that can be used to control the movement of a robot by using the extracted features of the EEG and EOG signals. The system records and classifies EEG as alpha, beta, delta, and theta waves. The classified brain waves are then used to define the level of attention. The acceleration and deceleration or stopping of the robot is controlled based on the attention level of the wearer. In addition, the left and right movements of eye ball control the direction of the robot.

Oh, Sechang; Kumar, Prashanth S.; Kwon, Hyeokjun; Varadan, Vijay K.

2012-04-01

310

Alpha-1-antitrypsin deficiency.  

PubMed

Alpha-1-antitrypsin deficiency (AATD) is a rare genetic disorder associated with the development of liver and lung disease. AAT is a 52-kD glycoprotein, produced mainly by hepatocytes and secreted into the blood. Agglomeration of the AAT-protein in hepatocytes can result in liver disease. Exposure to smoke is the major risk factor for the development of lung disease characterised as early chronic obstructive lung disease (COPD). Diagnosis is based on the analysis of the AAT genotype and phenotype. The measurement of the AAT serum level is useful as screening test. Liver biopsy is not necessary to establish the diagnosis. Therapy for AAT-related liver disease is supportive, a specific therapy is not available. AATD is a rare condition (1:5000-10000) and, as a consequence, data and information on diagnosis and treatment are not easily accessible. This chapter provides a comprehensive overview on AATD, covering basic biology, diagnostic and therapeutic approaches. PMID:20955965

Bals, Robert

2010-10-01

311

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

... Liver Disease Information > Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency Explore this section to learn more about alpha-1 antitrypsin deficiency, including a description of the disorder ...

312

EEG Dynamics Reflect the Distinct Cognitive Process of Optic Problem Solving  

PubMed Central

This study explores the changes in electroencephalographic (EEG) activity associated with the performance of solving an optics maze problem. College students (N?=?37) were instructed to construct three solutions to the optical maze in a Web-based learning environment, which required some knowledge of physics. The subjects put forth their best effort to minimize the number of convexes and mirrors needed to guide the image of an object from the entrance to the exit of the maze. This study examines EEG changes in different frequency bands accompanying varying demands on the cognitive process of providing solutions. Results showed that the mean power of ?, ?1, ?2, and ?1 significantly increased as the number of convexes and mirrors used by the students decreased from solution 1 to 3. Moreover, the mean power of ? and ?1 significantly increased when the participants constructed their personal optimal solution (the least total number of mirrors and lens used by students) compared to their non-personal optimal solution. In conclusion, the spectral power of frontal, frontal midline and posterior theta, posterior alpha, and temporal beta increased predominantly as the task demands and task performance increased. PMID:22815800

She, Hsiao-Ching; Jung, Tzyy-Ping; Chou, Wen-Chi; Huang, Li-Yu; Wang, Chia-Yu; Lin, Guan-Yu

2012-01-01

313

Effects of Galvanic Vestibular Stimulation on Visual Memory Recall and EEG  

PubMed Central

[Purpose] This study aimed to examine the effects of galvanic vestibular stimulation (GVS) on visual memory recall and EEG. [Subjects and Methods] In the present study, 42 adults were selected and divided equally into two groups of 21 adults, the GVS group and the Sham group. The error rate was calculated as a percentage based on the total number of errors in the answers to 24 questions after stimulation, while the reaction time was measured in intervals between the time the questions were asked and the time it took the subjects to answer the questions. EEG data were obtained by attaching electrodes to the Fz, Cz, and Pz points during the question and answer phase. [Results] The error rate showed statistically significant differences in the interaction involving the time of response and group. The reaction time showed no statistically significant differences in the interaction involving the time of response and group. When relative band power parameters were analyzed, alpha waves showed no statistically significant differences in the interaction involving the time of response and group, but only the Fz area of beta waves showed statistically significant differences in the interaction involving the time of response and group. [Conclusion] GVS may improve visual memory recall in relation to a flower, a person, an animal, or a building. PMID:25276011

Lee, Jeong-Woo; Lee, Gi-Eun; An, Ji-Hyang; Yoon, Se-Won; Heo, Myoung; Kim, Hwang-Yong

2014-01-01

314

Effects of galvanic vestibular stimulation on visual memory recall and EEG.  

PubMed

[Purpose] This study aimed to examine the effects of galvanic vestibular stimulation (GVS) on visual memory recall and EEG. [Subjects and Methods] In the present study, 42 adults were selected and divided equally into two groups of 21 adults, the GVS group and the Sham group. The error rate was calculated as a percentage based on the total number of errors in the answers to 24 questions after stimulation, while the reaction time was measured in intervals between the time the questions were asked and the time it took the subjects to answer the questions. EEG data were obtained by attaching electrodes to the Fz, Cz, and Pz points during the question and answer phase. [Results] The error rate showed statistically significant differences in the interaction involving the time of response and group. The reaction time showed no statistically significant differences in the interaction involving the time of response and group. When relative band power parameters were analyzed, alpha waves showed no statistically significant differences in the interaction involving the time of response and group, but only the Fz area of beta waves showed statistically significant differences in the interaction involving the time of response and group. [Conclusion] GVS may improve visual memory recall in relation to a flower, a person, an animal, or a building. PMID:25276011

Lee, Jeong-Woo; Lee, Gi-Eun; An, Ji-Hyang; Yoon, Se-Won; Heo, Myoung; Kim, Hwang-Yong

2014-09-01

315

Behavioral and EEG changes in male 5xFAD mice.  

PubMed

Transgenic animal models of Alzheimer's disease (AD) are widely used to investigate mechanisms of pathophysiology and cognitive dysfunctions. A model with a very early development of parenchymal plaque load at the age of 2months is the 5xFAD mouse (Tg6799, Oakley et al. 2006). These 5xFAD mice over-express both human amyloid precursor protein (APP) and human presenilin 1 (PS1). Mice from this line have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-? (A?). The aim of this study was the behavioral and functional investigations of 5xFAD males because in most studies females of this strain were characterized. In comparison to literature of transgenic 5xFAD females, transgenic 5xFAD males showed decreased anxiety in the elevated plus maze, reduced locomotion and exploration in the open field and disturbances in learning performance in the Morris water maze starting at 9months of age. Electroencephalogram (EEG) recordings on 6month old transgenic mice revealed a decrease of delta, theta, alpha, beta and gamma frequency bands whereas the subdelta frequency was increased. EEG recordings during sleep showed a reduction of rapid eye movement sleep in relation to the amount of total sleep. Thus, 5xFAD males develop early functional disturbances and subsequently behavioral deficits and therefore they are a good mouse model for studying Alzheimer's disease. PMID:24907698

Schneider, F; Baldauf, K; Wetzel, W; Reymann, K G

2014-08-01

316

A comparative study of the diagnostic value of drug-induced sleep EEGs and sleep EEGs following sleep deprivation in patients with complex partial seizures  

Microsoft Academic Search

The purpose of the study was to investigate whether the sleep EEG after sleep deprivation has a stronger provocative effect than the drug-induced sleep EEG. For this purpose a sleep EEG, induced by 2 mg\\/kg body weight of promazine hydrochloride, was recorded. On the following day a sleep EEG of the same patient was recorded after sleep deprivation of 24–26

R. Degen; H.-E. Degen

1981-01-01

317

Temporal dynamics of EEG activity during short- and long-wavelength light exposures in the early morning  

PubMed Central

Background It is well known that exposure to light, especially of short wavelength, enhances human alertness during the nighttime. However, more information is needed to elucidate the effects of light wavelength on alertness at other times of day. The present study investigated how two narrowband light spectra affected human alertness during the morning after awakening. We measured electroencephalography (EEG) during 48-minute exposure to narrowband short- and long-wavelength light and darkness in the early morning. Results Power densities of EEG during each light exposure were calculated. The time course of EEG power indicated that, compared with remaining in darkness, the power in the alpha frequency range (8–13 Hz) was significantly lower after approximately 30 minutes of exposures to both the short- and the long-wavelength light. Conclusions These results suggest that not only short-wavelength light but also long-wavelength light, which does not suppress melatonin levels at night, can affect alertness in the early morning. These results suggest that the alerting effects of light in the early morning hours may be mediated by mechanisms other than those that are exclusively sensitive to short-wavelength light. PMID:24568149

2014-01-01

318

Investigation of EEG changes during exposure to extremely low-frequency magnetic field to conduct brain signals.  

PubMed

There are evidences that confirm the effect of magnetic fields (MFs) on brain signals and some psychological disorders such as headache, migraine and depression. The aim of the present study was to investigate changes in EEG power spectrum due to localized exposure in different parts of the brain by extremely low-frequency magnetic fields (ELF-MFs) to extract some protocols for treatment of some psychological disorders. In addition, regular effects were investigated by increasing intensity of ELF-MF. Therefore, EEG relative power spectrum was evaluated at T4, T3, F3, F4, and Cz points, when all the points were exposed to MFs with 45, 17, 10, 5, and 3 Hz frequencies, separately. Intensity of MF was 0, 100, 240, or 360 ?T in four sessions. Significant changes were observed in different EEG bands caused by locally exposing to ELF-MF in different points of brain (P < 0.05). Some exposure to MFs decreased alpha band of frontal and central areas in closed-eyes state. Based on the findings in this study, some protocols can be designed using a combination of various MFs exposures to conduct the brain signals that is necessary to evaluate clinically. PMID:24864004

Shafiei, S A; Firoozabadi, S M; Tabatabaie, K Rasoulzadeh; Ghabaee, M

2014-11-01

319

Intelligence related differences in EEG-bandpower  

Microsoft Academic Search

Several studies on the relationship between event-related desynchronization\\/synchronization (ERD\\/ERS) and cognitive performance revealed contradictory results particularly for the alpha band. Studies from our laboratory have shown that good performers show a larger upper alpha ERD (interpreted in terms of larger cortical activation) than bad performers. In contrast, other researchers found evidence for the neural efficiency hypothesis, which states that more

Michael Doppelmayr; W. Klimesch; P. Sauseng; K. Hödlmoser; W. Stadler; S. Hanslmayr

2005-01-01

320

Multimodal spatial calibration for accurately registering EEG sensor positions.  

PubMed

This paper proposes a fast and accurate calibration method to calibrate multiple multimodal sensors using a novel photogrammetry system for fast localization of EEG sensors. The EEG sensors are placed on human head and multimodal sensors are installed around the head to simultaneously obtain all EEG sensor positions. A multiple views' calibration process is implemented to obtain the transformations of multiple views. We first develop an efficient local repair algorithm to improve the depth map, and then a special calibration body is designed. Based on them, accurate and robust calibration results can be achieved. We evaluate the proposed method by corners of a chessboard calibration plate. Experimental results demonstrate that the proposed method can achieve good performance, which can be further applied to EEG source localization applications on human brain. PMID:24803954

Zhang, Jianhua; Chen, Jian; Chen, Shengyong; Xiao, Gang; Li, Xiaoli

2014-01-01

321

DEPRESSED EXCITABILITY AND INTEGRATED EEGS FOLLOWING HIPPOCAMPAL AFTERDISCHARGES  

EPA Science Inventory

Rats with chronic hippocampal electrode implants had afterdischarges induced with electrical stimulus intensities of 115,200, and 800% of a previously determined threshold. Afterdischarge duration, postictal EEG depression duration, and the duration of postictal electrical hypoex...

322

Sparse dictionary methods for EEG signal classification in face perception  

E-print Network

This paper presents a systematic application of machine learning techniques for classifying high-density EEG signals elicited by face and non-face stimuli. The two stimuli used here are derived from the vase-faces illusion ...

Shariat, Shahriar

323

Multimodal Spatial Calibration for Accurately Registering EEG Sensor Positions  

PubMed Central

This paper proposes a fast and accurate calibration method to calibrate multiple multimodal sensors using a novel photogrammetry system for fast localization of EEG sensors. The EEG sensors are placed on human head and multimodal sensors are installed around the head to simultaneously obtain all EEG sensor positions. A multiple views' calibration process is implemented to obtain the transformations of multiple views. We first develop an efficient local repair algorithm to improve the depth map, and then a special calibration body is designed. Based on them, accurate and robust calibration results can be achieved. We evaluate the proposed method by corners of a chessboard calibration plate. Experimental results demonstrate that the proposed method can achieve good performance, which can be further applied to EEG source localization applications on human brain. PMID:24803954

Chen, Shengyong; Xiao, Gang; Li, Xiaoli

2014-01-01

324

ONLINE AUTOMATIC EPILEPTIC SEIZURE DETECTION FROM ELECTROENCEPHALOGRAM (EEG)  

E-print Network

ONLINE AUTOMATIC EPILEPTIC SEIZURE DETECTION FROM ELECTROENCEPHALOGRAM (EEG) By HUI LIU of this research possible. I appreciate his constant enthusiasm for guiding, searching, facilitating and driving.......................................................................................................................4 Seizure Classification and Artifact Categories

Slatton, Clint

325

Fractal Dimension in Eeg Signals during Muscle Fatigue  

NASA Astrophysics Data System (ADS)

Fractal dimension (FD) has been successfully used to characterize signals in the format of time series. In this study, we calculated FD of EEG signals recorded during human muscle fatigue as a measure of changes in the EEG signal complexity along fatigue. Subjects performed 200 intermittent handgrip contractions at 100contraction level. Each contraction lasted 2 s, followed by a 5-s rest. EEG data were recorded from the scalp along with handgrip force and muscle EMG signals. The FD computation was based on measurements of the length (Lk) of the signal at 6 different temporal resolutions (k = 1, 2, ¡­, 6). FD was determined from the relationship between Lk and k using the least square fit. The results showed that: (1) EEG fractal dimension associated with the motor performance was significantly higher than that during the rest period; (2) changes in the fractal dimension along the process of fatigue showed a significant correlation with the decline in force and EMG signals.

Huang, Haibin; Yao, Bin; Yue, Guang; Brown, Robert; Jing, Liu

2003-10-01

326

Electroencephalographic (EEG) control of three-dimensional movement  

NASA Astrophysics Data System (ADS)

Brain-computer interfaces (BCIs) can use brain signals from the scalp (EEG), the cortical surface (ECoG), or within the cortex to restore movement control to people who are paralyzed. Like muscle-based skills, BCIs' use requires activity-dependent adaptations in the brain that maintain stable relationships between the person's intent and the signals that convey it. This study shows that humans can learn over a series of training sessions to use EEG for three-dimensional control. The responsible EEG features are focused topographically on the scalp and spectrally in specific frequency bands. People acquire simultaneous control of three independent signals (one for each dimension) and reach targets in a virtual three-dimensional space. Such BCI control in humans has not been reported previously. The results suggest that with further development noninvasive EEG-based BCIs might control the complex movements of robotic arms or neuroprostheses.

McFarland, Dennis J.; Sarnacki, William A.; Wolpaw, Jonathan R.

2010-06-01

327

[Spatial organization of EEG in rats with genetically determined emotionality].  

PubMed

In order to study the possibility of EEG discrimination of genetically determined emotionality (increased propensity to emotional and stress reactions and anxiety) brain electrical activity was recorded in rats of two strains: Maudsley Reactive and Maudsley Nonreactive (24 derivations from the convexital skull surface were used). The program package "Synchro-EEG" was used for EEG processing. It was demonstrated that the two rat strains were significantly different in 120 EEG parameters of 840 ones analyzed. On the basis of 37 parameters, each rat was correctly recognized as belonging to the respective group with the error of 4.89%. The analysis of the detected signs allowed their classification to be performed in accordance with the peculiarities of the emotional and cognitive processes and the level of nonspecific activation. Specific forms of interaction between these components in the system of emotional reactions were revealed. PMID:10923382

Sviderskaia, N E; Seredenin, S B; Korol'kova, T A; Kozhechkin, S N; Koshtoiants, O Kh; Kozhedub, R G

2000-01-01

328

EEG (ELECTROENCEPHALOGRAM) AS A CROSS SPECIES INDICATOR OF NEUROTOXICITY  

EPA Science Inventory

The electroencephalogram (EEG) is a promising measure in the field of neurotoxicology. It can be well quantified by techniques which can be interpreted both physically and statistically. Such quantification schemes are briefly discussed in this paper. However, the quantification ...

329

Phenotypic switching in bacteria  

NASA Astrophysics Data System (ADS)

Living matter is a non-equilibrium system in which many components work in parallel to perpetuate themselves through a fluctuating environment. Physiological states or functionalities revealed by a particular environment are called phenotypes. Transitions between phenotypes may occur either spontaneously or via interaction with the environment. Even in the same environment, genetically identical bacteria can exhibit different phenotypes of a continuous or discrete nature. In this thesis, we pursued three lines of investigation into discrete phenotypic heterogeneity in bacterial populations: the quantitative characterization of the so-called bacterial persistence, a theoretical model of phenotypic switching based on those measurements, and the design of artificial genetic networks which implement this model. Persistence is the phenotype of a subpopulation of bacteria with a reduced sensitivity to antibiotics. We developed a microfluidic apparatus, which allowed us to monitor the growth rates of individual cells while applying repeated cycles of antibiotic treatments. We were able to identify distinct phenotypes (normal and persistent) and characterize the stochastic transitions between them. We also found that phenotypic heterogeneity was present prior to any environmental cue such as antibiotic exposure. Motivated by the experiments with persisters, we formulated a theoretical model describing the dynamic behavior of several discrete phenotypes in a periodically varying environment. This theoretical framework allowed us to quantitatively predict the fitness of dynamic populations and to compare survival strategies according to environmental time-symmetries. These calculations suggested that persistence is a strategy used by bacterial populations to adapt to fluctuating environments. Knowledge of the phenotypic transition rates for persistence may provide statistical information about the typical environments of bacteria. We also describe a design of artificial genetic networks that would implement a more general theoretical model of phenotypic switching. We will use a new cloning strategy in order to systematically assemble a large number of genetic features, such as site-specific recombination components from the R64 plasmid, which invert several coexisting DNA segments. The inversion of these segments would lead to discrete phenotypic transitions inside a living cell. These artificial phenotypic switches can be controlled precisely in experiments and may serve as a benchmark for their natural counterparts.

Merrin, Jack

330

Modifications in the human EEG during extralong physical activity  

Microsoft Academic Search

In a single-case study, the effects of very long-lasting physical exercise, namely a 24-h-long ultramarathon, on the human\\u000a electroencephalogram (EEG) were evaluated. While only effects of relatively short exercise have been reported earlier, we\\u000a focused on the changes induced by these long-lasting physical requires. EEG was recorded repeatedly using an auditory oddball\\u000a paradigm, and event-related potentials (ERPs), as well as

M. Doppelmayr; P. Sauseng; H. Doppelmayr

2007-01-01

331

High Frequency EEG and Its Relationship to Cognitive Function  

Microsoft Academic Search

Objective assessment of the sleep-wake states in clinical and laboratory settings is determined from the electroencephalogram\\u000a (EEG) as recordings of brain electrical signals. The EEG record is visually scored according to the awake state and 4 stages\\u000a of varying sleep depth, as well as a “rapid eye movement” (REM) or the dream stage. Drowsiness or the state between awake\\u000a and

H. C. Sing

332

Folate receptor {alpha} regulates cell proliferation in mouse gonadotroph {alpha}T3-1 cells  

SciTech Connect

We have previously found that the mRNA and protein levels of the folate receptor alpha (FR{alpha}) are uniquely over-expressed in clinically human nonfunctional (NF) pituitary adenomas, but the mechanistic role of FR{alpha} has not fully been determined. We investigated the effect of FR{alpha} over-expression in the mouse gonadotroph {alpha}T3-1 cell line as a model for NF pituitary adenomas. We found that the expression and function of FR{alpha} were strongly up-regulated, by Western blotting and folic acid binding assay. Furthermore, we found a higher cell growth rate, an enhanced percentage of cells in S-phase by BrdU assay, and a higher PCNA staining. These observations indicate that over-expression of FR{alpha} promotes cell proliferation. These effects were abrogated in the same {alpha}T3-1 cells when transfected with a mutant FR{alpha} cDNA that confers a dominant-negative phenotype by inhibiting folic acid binding. Finally, by real-time quantitative PCR, we found that mRNA expression of NOTCH3 was up-regulated in FR{alpha} over-expressing cells. In summary, our data suggests that FR{alpha} regulates pituitary tumor cell proliferation and mechanistically may involve the NOTCH pathway. Potentially, this finding could be exploited to develop new, innovative molecular targeted treatment for human NF pituitary adenomas.

Yao, Congjun; Evans, Chheng-Orn [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States)] [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States); Stevens, Victoria L. [Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia (United States)] [Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia (United States); Owens, Timothy R. [Emory University, School of Medicine, Atlanta, Georgia (United States)] [Emory University, School of Medicine, Atlanta, Georgia (United States); Oyesiku, Nelson M., E-mail: noyesik@emory.edu [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States)

2009-11-01

333

Dynamic links between theta executive functions and alpha storage buffers in auditory and visual working memory  

PubMed Central

Working memory (WM) tasks require not only distinct functions such as a storage buffer and central executive functions, but also coordination among these functions. Neuroimaging studies have revealed the contributions of different brain regions to different functional roles in WM tasks; however, little is known about the neural mechanism governing their coordination. Electroencephalographic (EEG) rhythms, especially theta and alpha, are known to appear over distributed brain regions during WM tasks, but the rhythms associated with task-relevant regional coupling have not been obtained thus far. In this study, we conducted time–frequency analyses for EEG data in WM tasks that include manipulation periods and memory storage buffer periods. We used both auditory WM tasks and visual WM tasks. The results successfully demonstrated function-specific EEG activities. The frontal theta amplitudes increased during the manipulation periods of both tasks. The alpha amplitudes increased during not only the manipulation but also the maintenance periods in the temporal area for the auditory WM and the parietal area for the visual WM. The phase synchronization analyses indicated that, under the relevant task conditions, the temporal and parietal regions show enhanced phase synchronization in the theta bands with the frontal region, whereas phase synchronization between theta and alpha is significantly enhanced only within the individual areas. Our results suggest that WM task-relevant brain regions are coordinated by distant theta synchronization for central executive functions, by local alpha synchronization for the memory storage buffer, and by theta–alpha coupling for inter-functional integration. PMID:20525081

Kawasaki, Masahiro; Kitajo, Keiichi; Yamaguchi, Yoko

2010-01-01

334

Methodological aspects of EEG and body dynamics measurements during motion  

PubMed Central

EEG involves the recording, analysis, and interpretation of voltages recorded on the human scalp which originate from brain gray matter. EEG is one of the most popular methods of studying and understanding the processes that underlie behavior. This is so, because EEG is relatively cheap, easy to wear, light weight and has high temporal resolution. In terms of behavior, this encompasses actions, such as movements that are performed in response to the environment. However, there are methodological difficulties which can occur when recording EEG during movement such as movement artifacts. Thus, most studies about the human brain have examined activations during static conditions. This article attempts to compile and describe relevant methodological solutions that emerged in order to measure body and brain dynamics during motion. These descriptions cover suggestions on how to avoid and reduce motion artifacts, hardware, software and techniques for synchronously recording EEG, EMG, kinematics, kinetics, and eye movements during motion. Additionally, we present various recording systems, EEG electrodes, caps and methods for determinating real/custom electrode positions. In the end we will conclude that it is possible to record and analyze synchronized brain and body dynamics related to movement or exercise tasks. PMID:24715858

Reis, Pedro M. R.; Hebenstreit, Felix; Gabsteiger, Florian; von Tscharner, Vinzenz; Lochmann, Matthias

2014-01-01

335

Multimodal detection of head-movement artefacts in EEG.  

PubMed

Artefacts arising from head movements have been a considerable obstacle in the deployment of automatic event detection systems in ambulatory EEG. Recently, gyroscopes have been identified as a useful modality for providing complementary information to the head movement artefact detection task. In this work, a comprehensive data fusion analysis is conducted to investigate how EEG and gyroscope signals can be most effectively combined to provide a more accurate detection of head-movement artefacts in the EEG. To this end, several methods of combining these physiological and physical signals at the feature, decision and score fusion levels are examined. Results show that combination at the feature, score and decision levels is successful in improving classifier performance when compared to individual EEG or gyroscope classifiers, thus confirming that EEG and gyroscope signals carry complementary information regarding the detection of head-movement artefacts in the EEG. Feature fusion and the score fusion using the sum-rule provided the greatest improvement in artefact detection. By extending multimodal head-movement artefact detection to the score and decision fusion domains, it is possible to implement multimodal artefact detection in environments where gyroscope signals are intermittently available. PMID:23685269

O'Regan, Simon; Marnane, William

2013-08-15

336

Rapidly Learned Identification of Epileptic Seizures from Sonified EEG  

PubMed Central

Sonification refers to a process by which data are converted into sound, providing an auditory alternative to visual display. Currently, the prevalent method for diagnosing seizures in epilepsy is by visually reading a patient’s electroencephalogram (EEG). However, sonification of the EEG data provides certain advantages due to the nature of human auditory perception. We hypothesized that human listeners will be able to identify seizures from EEGs using the auditory modality alone, and that accuracy of seizure identification will increase after a short training session. Here, we describe an algorithm that we have used to sonify EEGs of both seizure and non-seizure activity, followed by a training study in which subjects listened to short clips of sonified EEGs and determined whether each clip was of seizure or normal activity, both before and after a short training session. Results show that before training subjects performed at chance level in differentiating seizures from non-seizures, but there was a significant improvement of accuracy after the training session. After training, subjects successfully distinguished seizures from non-seizures using the auditory modality alone. Further analyses using signal detection theory demonstrated improvement in sensitivity and reduction in response bias as a result of training. This study demonstrates the potential of sonified EEGs to be used for the detection of seizures. Future studies will attempt to increase accuracy using novel training and sonification modifications, with the goals of managing, predicting, and ultimately controlling seizures using sonification as a possible biofeedback-based intervention for epilepsy.

Loui, Psyche; Koplin-Green, Matan; Frick, Mark; Massone, Michael

2014-01-01

337

Infraslow EEG oscillations organize large-scale cortical-subcortical interactions during sleep: a combined EEG/fMRI study.  

PubMed

Infraslow (<0.1 Hz) oscillations of brain activity, measured by EEG and other methods, have become a subject of increasing interest. While their prominence during sleep has been established, the functional significance of these oscillations for sleep physiology is unknown. To clarify this role, we examined correlations between infraslow EEG oscillations and BOLD fMRI during the course of natural sleep in healthy volunteers. Infraslow EEG oscillations appear to organize a broad dissociation of activity in cortical and subcortical regions: in general, correlations between power in the infraslow EEG band and BOLD were positive in subcortical regions and negative in the cortex. Robust negative correlations were found principally in paramedian heteromodal cortices whereas positive correlations were seen in cerebellum, thalamus, basal ganglia, lateral neocortices and hippocampus. This pattern of correlations suggests a mechanism by which infraslow oscillations may organize sleep-dependent neuroplastic processes including consolidation of episodic memory. PMID:21168395

Picchioni, Dante; Horovitz, Silvina G; Fukunaga, Masaki; Carr, Walter S; Meltzer, Jed A; Balkin, Thomas J; Duyn, Jeff H; Braun, Allen R

2011-02-16

338

Third order spectral analysis robust to mixing artifacts for mapping cross-frequency interactions in EEG/MEG.  

PubMed

We present a novel approach to the third order spectral analysis, commonly called bispectral analysis, of electroencephalographic (EEG) and magnetoencephalographic (MEG) data for studying cross-frequency functional brain connectivity. The main obstacle in estimating functional connectivity from EEG and MEG measurements lies in the signals being a largely unknown mixture of the activities of the underlying brain sources. This often constitutes a severe confounder and heavily affects the detection of brain source interactions. To overcome this problem, we previously developed metrics based on the properties of the imaginary part of coherency. Here, we generalize these properties from the linear to the nonlinear case. Specifically, we propose a metric based on an antisymmetric combination of cross-bispectra, which we demonstrate to be robust to mixing artifacts. Moreover, our metric provides complex-valued quantities that give the opportunity to study phase relationships between brain sources. The effectiveness of the method is first demonstrated on simulated EEG data. The proposed approach shows a reduced sensitivity to mixing artifacts when compared with a traditional bispectral metric. It also exhibits a better performance in extracting phase relationships between sources than the imaginary part of the cross-spectrum for delayed interactions. The method is then applied to real EEG data recorded during resting state. A cross-frequency interaction is observed between brain sources at 10Hz and 20Hz, i.e., for alpha and beta rhythms. This interaction is then projected from signal to source level by using a fit-based procedure. This approach highlights a 10-20Hz dominant interaction localized in an occipito-parieto-central network. PMID:24418509

Chella, F; Marzetti, L; Pizzella, V; Zappasodi, F; Nolte, G

2014-05-01

339

Improvements of Adaptive Filtering by Optimal Projection to filter different artifact types on long duration EEG recordings.  

PubMed

Adaptive Filtering by Optimal Projection (AFOP) is an automatic method for reducing ocular and muscular artifacts on electro-encephalographic (EEG) recordings. This paper presents two additions to this method: an improvement of the stability of ocular artifact filtering and an adaptation of the method for filtering electrode artifacts. With these improvements, it is possible to reduce almost all the current types of artifacts, while preserving brain signals, particularly those characterising epilepsy. This generalised method consists of dividing the signal into several time-frequency windows, and in applying different spatial filters to each. Two steps are required to define one of these spatial filters: the first step consists of defining artifact spatial projection using the Common Spatial Pattern (CSP) method and the second consists of defining EEG spatial projection via regression. For this second step, a progressive orthogonalisation process is proposed to improve stability. This method has been tested on long-duration EEG recordings of epileptic patients. A neurologist quantified the ratio of removed artifacts and the ratio of preserved EEG. Among the 330 artifacted pages used for evaluation, readability was judged better for 78% of pages, equal for 20% of pages, and worse for 2%. Artifact amplitudes were reduced by 80% on average. At the same time, brain sources were preserved in amplitude from 70% to 95% depending on the type of waves (alpha, theta, delta, spikes, etc.). A blind comparison with manual Independent Component Analysis (ICA) was also realised. The results show that this method is competitive and useful for routine clinical practice. PMID:22717094

Boudet, S; Peyrodie, L; Forzy, G; Pinti, A; Toumi, H; Gallois, P

2012-10-01

340

Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: no association with neuroaxonal dystrophy?  

PubMed

Two new individuals with alpha-NAGA deficiency are presented. The index patient, 3 years old, has congenital cataract, slight motor retardation and secondary demyelinisation. Screening of his sibs revealed an alpha-NAGA deficiency in his 7-year-old healthy brother who had no clinical or neurological symptoms. Both sibs are homozygous for the E325K mutation, the same genotype that was found in the most severe form of alpha-NAGA deficiency presenting as infantile neuroaxonal dystrophy. Thus, at the age of 7 years the same genotype of alpha-NAGA may present as a 'non-disease' (present healthy case) and can be associated with the vegetative state (the first two patients described with alpha-NAGA deficiency). The clinical heterogeneity among the 11 known individuals with alpha-NAGA deficiency is extreme, with a 'non-disease' (two cases) and infantile neuroaxonal dystrophy (two cases) at the opposite sides of the clinical spectrum. The broad spectrum is completed by a very heterogeneous group of patients with various degrees of epilepsy/behavioural difficulties/psychomotor retardation (four patients) and a mild phenotype in adults without overt neurological manifestations who have angiokeratoma and clear vacuolisation in various cell types (three cases). These observations are difficult to reconcile with a straightforward genotype-phenotype correlation and suggest that factors or genes other than alpha-NAGA contribute to the clinical heterogeneity of the 11 patients with alpha-NAGA deficiency. PMID:11313741

Bakker, H D; de Sonnaville, M L; Vreken, P; Abeling, N G; Groener, J E; Keulemans, J L; van Diggelen, O P

2001-02-01

341

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. PMID:17023555

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

2007-01-01

342

[The role of non-NMDA glutamate receptors in the EEG effects of chronic administration of noopept GVS-111 in awake rats].  

PubMed

Participation of the non-NMDA glutamate receptor subtype in the formation of the EEG frequency spectrum was studied in wakeful rats upon a long-term (10 x 0.2 mg/kg, s.c.) administration of the nootropic dipeptide GVS-111 (noopept or N-phenylacetyl-L-prolyglycine ethylate). The EEGs were measured with electrodes implanted into somatosensor cortex regions, hippocampus, and a cannula in the lateral ventricle. The acute reactions (characteristic of nootropes) in the alpha and beta ranges of EEG exhibited inversion after the 6th injection of noopept and almost completely vanished after the 9th injection. Preliminary introduction of the non-NMDA antagonist GDEE (glutamic acid diethyl ester) in a dose of 1 mumole into the lateral ventricle restored the EEG pattern observed upon the 6th dose of GVS-111. The role of glutamate receptors in the course of a prolonged administration of nootropes, as well as the possible mechanisms accounting for a difference in the action of GVS-111 and piracetam are discussed. PMID:12596524

Kovalev, G I; Vorob'ev, V V

2002-01-01

343

The effects of ethanol on EEG activity in males at risk for alcoholism.  

PubMed

The present investigation examined the effects of placebo (P), low dose (LD) and high dose (HD) ethanol on EEG activity in two groups of males. One group consisted of individuals at high risk for the development of alcoholism (HR, N = 21) while the other consisted of matched, low risk (LR, N = 21) controls. Only one condition (P, LD or HD) was presented each day and condition order was randomized. For each subject, both blood alcohol level(s) (BAL) measured via breathalyzer and EEG activity, using the entire 10/20 international system, were recorded prior to and at intervals of 35, 70, 105 and 140 min after P, LD or HD administration. The Fast Fourier Transform (FFT) was used to calculate power spectral densities (PSD). Measures of relative area under the power spectral curve were obtained for each of the following frequency bands: slow alpha (SA, 7.5-10 Hz), fast alpha (FA, 10.5-13.0 Hz), slow beta (SB, 13.5-19.5 Hz) and fast beta (FB, 20-26 Hz) at electrodes: F3, F4, C3, C4, P3, P4, O1 and O2. The results of repeated measures MANOVA conducted on the normalized values of relative areas revealed that at each electrode examined, ethanol elicited significant changes only in SA activity. Risk group differences in SA activity were observed only at electrodes F3, F4 and P4. These differences were the consequence of differential ethanol effects rather than differences in baseline SA levels.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7686471

Cohen, H L; Porjesz, B; Begleiter, H

1993-06-01

344

A study on validity of cortical alpha connectivity for schizophrenia.  

PubMed

Abnormalities in schizophrenia are thought to be associated with functional disconnections between different brain regions. Most previous studies on schizophrenia have considered high-band connectivity in preference to the Alpha band, as there has been some uncertainty correlating the latter to the condition. In this paper we attempt to clarify this correlation using an Electroencephalogram (EEG) analysis of the Alpha band from schizophrenic patients. Global, regional Omega and dimensional complexity and local Omega complexity differentials (LCD) of single channel are calculated using 16 channels of resting EEG data from 31 adult patients with schizophrenia and 31 age/sex matched control subjects. It was found that, compared to the controls, anterior alpha Omega and dimensional complexity are higher in schizophrenia patients (p<0.05) with the single channel LCD also increasing at FP1, FP2, F7 and F8 electrodes. Furthermore, higher left hemisphere dimensional complexity and LCD at T3 point was also found. The results suggest there is lower connectivity in the pre-frontal and left temporal regions with respect to the alpha band in schizophrenia patients. PMID:24110430

Peng, Hong; Hu, Bin; Li, Lanlan; Ratcliffe, Martyn; Zhai, Jingwei; Zhao, Qinglin; Shi, Qiuxia; Li, Yunpeng; Liu, Quanying

2013-01-01

345

GABAA receptor beta3 subunit gene-deficient heterozygous mice show parent-of-origin and gender-related differences in beta3 subunit levels, EEG, and behavior.  

PubMed

The homozygous knockout mouse for the beta3 subunit of the GABAA receptor has been proposed as a model for the neurodevelopmental disorder, Angelman syndrome, based on phenotypic similarities of craniofacial abnormalities, cognitive defects, hyperactivity, motor incoordination, disturbed rest-activity cycles, and epilepsy. Since most children with Angelman syndrome are autosomal heterozygotes of maternal origin, apparently through genomic imprinting, we used gabrb3-deficient heterozygote mice of defined parental origin to investigate whether this phenotype is also maternally imprinted in mouse. Whole brain extracts showed greatly reduced beta3 subunit levels in male mice of maternal origin but not in male mice of paternal origin. Females of both parental origin showed greatly reduced beta3 subunit levels. Heterozygotes did not exhibit hyperactive circling behavior, convulsions, or electrographically recorded seizures. EEGs showed qualitative differences among heterozygotes, with male mice of maternal origin demonstrating more abnormalities including increased theta activity. Ethosuximide inhibited theta bursts, suggesting an alteration in the thalamocortical relay. Carbamazepine induced EEG slowing in males and EEG acceleration in females, with a larger effect in paternal-origin heterozygotes. Evidence thus suggests both parent-of-origin and gender-related components in developmental regulation of beta3 expression, in particular, that the maternally-derived male heterozygote may carry a developmental modification resulting in less beta3 protein, which may reflect partial genomic imprinting of the gabrb3 gene in mice. PMID:15878204

Liljelund, Patricia; Handforth, Adrian; Homanics, Gregg E; Olsen, Richard W

2005-06-30

346

Mixed phenotype murine leukemias.  

PubMed

Cell lines were derived from eight individual leukemias induced by X-rays in NFS mice. First typed as null cells (surface immunoglobulin negative, Thy-1 negative), they turned out to have a mixed phenotype with myeloid cytochemical markers, pre-B surface antigens and molecular markers of pro-B lymphocytes. They represent murine models for mixed phenotype (pro-pre-B-myeloid) leukemias. PMID:8350626

Defresne, M P; Borremans, B; Verhofstede, C; Peled, A; Thiry, A; Greimers, R; Robberecht, P; Nabarra, B; Verschaeve, L; Hooghe, R

1993-08-01

347

The integrated phenotype.  

PubMed

Proper functioning of complex phenotypes requires that multiple traits work together. Examination of relationships among traits within and between complex characters and how they interact to function as a whole organism is critical to advancing our understanding of evolutionary developmental plasticity. Phenotypic integration refers to the relationships among multiple characters of a complex phenotype, and their relationships with other functional units (modules) in an organism. In this review, I summarize a brief history of the concept of phenotypic integration in plant and animal biology. Following an introduction of concepts, including modularity, I use an empirical case-study approach to highlight recent advance in clarifying the developmental and genomic basis of integration. I end by highlighting some novel approaches to genomic and epigenetic perturbations that offer promise in further addressing the role of phenotypic integration in evolutionary diversification. In the age of the phenotype, studies that examine the genomic and developmental changes in relationships of traits across environments will shape the next chapter in our quest for understanding the evolution of complex characters. PMID:22593559

Murren, Courtney J

2012-07-01

348

Macrophage phenotypes in atherosclerosis.  

PubMed

Initiation and progression of atherosclerosis depend on local inflammation and accumulation of lipids in the vascular wall. Although many cells are involved in the development and progression of atherosclerosis, macrophages are fundamental contributors. For nearly a decade, the phenotypic heterogeneity and plasticity of macrophages has been studied. In atherosclerotic lesions, macrophages are submitted to a large variety of micro-environmental signals, such as oxidized lipids and cytokines, which influence the phenotypic polarization and activation of macrophages resulting in a dynamic plasticity. The macrophage phenotype spectrum is characterized, at the extremes, by the classical M1 macrophages induced by T-helper 1 (Th-1) cytokines and by the alternative M2 macrophages induced by Th-2 cytokines. M2 macrophages can be further classified into M2a, M2b, M2c, and M2d subtypes. More recently, additional plaque-specific macrophage phenotypes have been identified, termed as Mox, Mhem, and M4. Understanding the mechanisms and functional consequences of the phenotypic heterogeneity of macrophages will contribute to determine their potential role in lesion development and plaque stability. Furthermore, research on macrophage plasticity could lead to novel therapeutic approaches to counteract cardiovascular diseases such as atherosclerosis. The present review summarizes our current knowledge on macrophage subsets in atherosclerotic plaques and mechanism behind the modulation of the macrophage phenotype. PMID:25319333

Colin, Sophie; Chinetti-Gbaguidi, Giulia; Staels, Bart

2014-11-01

349

Generation and Reproductive Phenotypes of Mice Lacking Estrogen Receptor beta  

Microsoft Academic Search

Estrogens influence the differentiation and maintenance of reproductive tissues and affect lipid metabolism and bone remodeling. Two estrogen receptors (ERs) have been identified to date, ERalpha and ERbeta . We previously generated and studied knockout mice lacking estrogen receptor alpha and reported severe reproductive and behavioral phenotypes including complete infertility of both male and female mice and absence of breast

John H. Krege; Jeffrey B. Hodgin; John F. Couse; Eva Enmark; Margaret Warner; Joel F. Mahler; Madhabananda Sar; Kenneth S. Korach; Jan-Ake Gustafsson; Oliver Smithies

1998-01-01

350

A review of EEG and MEG for brainnetome research.  

PubMed

The majority of brain activities are performed by functionally integrating separate regions of the brain. Therefore, the synchronous operation of the brain's multiple regions or neuronal assemblies can be represented as a network with nodes that are interconnected by links. Because of the complexity of brain interactions and their varying effects at different levels of complexity, one of the corresponding authors of this paper recently proposed the brainnetome as a new -ome to explore and integrate the brain network at different scales. Because electroencephalography (EEG) and magnetoencephalography (MEG) are noninvasive and have outstanding temporal resolution and because they are the primary clinical techniques used to capture the dynamics of neuronal connections, they lend themselves to the analysis of the neural networks comprising the brainnetome. Because of EEG/MEG's applicability to brainnetome analyses, the aim of this review is to identify the procedures that can be used to form a network using EEG/MEG data in sensor or source space and to promote EEG/MEG network analysis for either neuroscience or clinical applications. To accomplish this aim, we show the relationship of the brainnetome to brain networks at the macroscale and provide a systematic review of network construction using EEG and MEG. Some potential applications of the EEG/MEG brainnetome are to use newly developed methods to associate the properties of a brainnetome with indices of cognition or disease conditions. Associations based on EEG/MEG brainnetome analysis may improve the comprehension of the functioning of the brain in neuroscience research or the recognition of abnormal patterns in neurological disease. PMID:24624229

Zhang, Xin; Lei, Xu; Wu, Ting; Jiang, Tianzi

2014-04-01

351

Signal distortion from microelectrodes in clinical EEG acquisition systems  

PubMed Central

Many centers are now using high-density microelectrodes during traditional intracranial EEG (iEEG) both for research and clinical purposes. These microelectrodes are FDA-approved and integrate into clinical EEG acquisition systems. However, the electrical characteristics of these electrodes are poorly described and clinical systems were not designed to use them; thus it is possible that this shift into clinical practice could have unintended consequences. In this study, we characterized the impedance of over 100 commercial macro- and microelectrodes using electrochemical impedance spectroscopy (EIS) to determine how electrode properties could affect signal acquisition and interpretation. The EIS data were combined with the published specifications of several commercial EEG systems to design digital filters that mimic the behavior of the electrodes and amplifiers. These filters were used to analyze simulated brain signals that contain a mixture of characteristic features commonly observed in iEEG. Each output was then processed with several common quantitative EEG measurements. Our results show that traditional macroelectrodes had low impedances and produced negligible distortion of the original signal. Brain tissue and electrical wiring also had negligible filtering effects. However, microelectrode impedances were much higher and more variable than the macroelectrodes. When connected to clinical amplifiers, higher impedance electrodes produced considerable distortion of the signal at low frequencies (< 60 Hz), which caused significant changes in amplitude, phase, variance, and spectral band power. In contrast, there were only minimal changes to the signal content for frequencies above 100 Hz. In order to minimize distortion with microelectrodes, we determined that an acquisition system should have an input impedance of at least 1 G?, which is much higher than most clinical systems. These results show that it is critical to account for variations in impedance when analyzing EEG from different-sized electrodes. Data from microelectrodes may yield misleading results unless recorded with high-impedance amplifiers. PMID:22878608

Stacey, William C.; Kellis, Spencer; Patel, Paras R.; Greger, Bradley; Butson, Christopher R.

2012-01-01

352

Origins of an Intrinsic Hippocampal EEG Pattern  

PubMed Central

Sharp waves (SPWs) are irregular waves that originate in field CA3 and spread throughout the hippocampus when animals are alert but immobile or as a component of the sleep EEG. The work described here used rat hippocampal slices to investigate the factors that initiate SPWs and govern their frequency. Acute transection of the mossy fibers reduced the amplitude but not the frequency of SPWs, suggesting that activity in the dentate gyrus may enhance, but is not essential for, the CA3 waves. However, selective destruction of the granule cells and mossy fibers by in vivo colchicine injections profoundly depressed SPW frequency. Reducing mossy fiber release with an mGluR2 receptor agonist or enhancing it with forskolin respectively depressed or increased the incidence of SPWs. Collectively, these results indicate that SPWs can be triggered by constitutive release from the mossy fibers. The waves were not followed by large after-hyperpolarizing potentials and their frequency was not strongly affected by blockers of various slow potassium channels. Antagonists of GABA-B mediated IPSCs also had little effect on incidence. It appears from these results that the spacing of SPWs is not dictated by slow potentials. However, modeling work suggests that the frequency and variance of large mEPSCs from the mossy boutons can account for the temporal distribution of the waves. Together, these results indicate that constitutive release from the mossy fiber terminal boutons regulates the incidence of SPWs and their contribution to information processing in hippocampus. PMID:19907647

Rex, Christopher S.; Colgin, Laura L.; Jia, Yousheng; Casale, Malcolm; Yanagihara, Theodore K.; Debenedetti, Maria; Gall, Christine M.; Kramar, Eniko A.; Lynch, Gary

2009-01-01

353

EEG spectral power density profiles during NREM sleep for gaboxadol and zolpidem in patients with primary insomnia.  

PubMed

There is significant interest in the functional significance and the therapeutic value of slow-wave sleep (SWS)-enhancing drugs. A prerequisite for studies of the functional differences is characterization of the electroencephalography (EEG) spectra following treatment in relevant patients. We evaluate for the first time gaboxadol and zolpidem treatments in insomniac patients using power spectra analysis. We carried out two randomized, double-blind, crossover studies. Study 1, 38 patients received gaboxadol 10 mg and 20 mg and zolpidem 10 mg; study 2, 23 patients received gaboxadol 5 mg and 15 mg. Treatments were administered during two nights and compared with placebo. Gaboxadol 10, 15 and 20 mg enhanced slow-wave activity (SWA) and theta power. In 1 Hz bins gaboxadol 10 and 20 mg enhanced power up to 9 Hz. In study 2, 15 mg gaboxadol showed a similar effect pattern. Zolpidem suppressed theta and alpha power, and increased sigma power, with no effect on SWA. In the 1 Hz bins zolpidem suppressed power between 5-10 Hz. Gaboxadol dose-dependently increased SWA and theta power in insomniac patients. In contrast, zolpidem did not affect SWA, reduced theta and alpha activity and enhanced sigma power. EEG spectral power differences may be consequences of the different mechanisms of action for zolpidem and the SWS-enhancing agent, gaboxadol. PMID:22057018

Lundahl, Jonas; Deacon, Steve; Maurice, Damien; Staner, Luc

2012-08-01

354

Sleep and EEG spectra in the pigeon ( Columba livia ) under baseline conditions and after sleep deprivation  

Microsoft Academic Search

Sleep in adult domestic pigeons was studied by continuous 24-h recording of the EEG, EMG and EOG. Vigilance states were scored on the basis of behavioral observations, visual scoring of the polygraph records, and EEG power spectra.

Irene Tobler; Alexander A. Borbély

1988-01-01

355

EXAMINING ASSOCIATIONS BETWEEN FMRI AND EEG DATA USING CANONICAL CORRELATION ANALYSIS  

E-print Network

EXAMINING ASSOCIATIONS BETWEEN FMRI AND EEG DATA USING CANONICAL CORRELATION ANALYSIS Nicolle Albuquerque, NM 87131 ABSTRACT Functional magnetic resonance imaging (fMRI) and electro- encephalography (EEG associations between these two modalities using canonical correlation analysis (CCA). Our multimodal canonical

Adali, Tulay

356

Quantitative change of EEG and respiration signals during mindfulness meditation  

PubMed Central

Background This study investigates measures of mindfulness meditation (MM) as a mental practice, in which a resting but alert state of mind is maintained. A population of older people with high stress level participated in this study, while electroencephalographic (EEG) and respiration signals were recorded during a MM intervention. The physiological signals during meditation and control conditions were analyzed with signal processing. Methods EEG and respiration data were collected and analyzed on 34 novice meditators after a 6-week meditation intervention. Collected data were analyzed with spectral analysis, phase analysis and classification to evaluate an objective marker for meditation. Results Different frequency bands showed differences in meditation and control conditions. Furthermore, we established a classifier using EEG and respiration signals with a higher accuracy (85%) at discriminating between meditation and control conditions than a classifier using the EEG signal only (78%). Conclusion Support vector machine (SVM) classifier with EEG and respiration feature vector is a viable objective marker for meditation ability. This classifier should be able to quantify different levels of meditation depth and meditation experience in future studies. PMID:24939519

2014-01-01

357

Localised astroglial dysfunction disrupts high-frequency EEG rhythms.  

PubMed

We used cerebral cortex injections of fluorocitrate to determine if selective astrocytic disturbances affect the electroencephalogram (EEG). Rats were halothane-anaesthetized and 0.8 nmol of sodium fluorocitrate was injected into hindlimb (motor-sensory) cortex. Extra-dural EEG electrodes were implanted after which the anaesthesia was ceased. EEG was recorded at 1, 3, 5, 7, 24 and 48 hours. There was a broad-band reduction in frequencies in the EEG between 20 and 100 Hz commencing within 1 hour of injection and largely restricted to the side of injection and to frontal cortex, and maximal at 3 hours. Halothane had a suppressive effect on gamma power after citrate injection, but also prevented EEG suppression caused by fluorocitrate, consistent with the hypothesis that some of the action of fluorocitrate depended on gap-junctions. The findings are consistent with the hypothesis that primary astroglial dysfunction leads to reduced neuronal transmission and further supports gap-junctions as mediating fluorocitrate-induced astroglial effects. PMID:15365787

Willoughby, J O; Mackenzie, L; Pope, K J; Broberg, M; Nilsson, M

2005-02-01

358

Nonlinear EEG Decoding Based on a Particle Filter Model  

PubMed Central

While the world is stepping into the aging society, rehabilitation robots play a more and more important role in terms of both rehabilitation treatment and nursing of the patients with neurological diseases. Benefiting from the abundant contents of movement information, electroencephalography (EEG) has become a promising information source for rehabilitation robots control. Although the multiple linear regression model was used as the decoding model of EEG signals in some researches, it has been considered that it cannot reflect the nonlinear components of EEG signals. In order to overcome this shortcoming, we propose a nonlinear decoding model, the particle filter model. Two- and three-dimensional decoding experiments were performed to test the validity of this model. In decoding accuracy, the results are comparable to those of the multiple linear regression model and previous EEG studies. In addition, the particle filter model uses less training data and more frequency information than the multiple linear regression model, which shows the potential of nonlinear decoding models. Overall, the findings hold promise for the furtherance of EEG-based rehabilitation robots. PMID:24949420

Hong, Jun

2014-01-01

359

Detection of Epileptic Seizure Event and Onset Using EEG  

PubMed Central

This study proposes a method of automatic detection of epileptic seizure event and onset using wavelet based features and certain statistical features without wavelet decomposition. Normal and epileptic EEG signals were classified using linear classifier. For seizure event detection, Bonn University EEG database has been used. Three types of EEG signals (EEG signal recorded from healthy volunteer with eye open, epilepsy patients in the epileptogenic zone during a seizure-free interval, and epilepsy patients during epileptic seizures) were classified. Important features such as energy, entropy, standard deviation, maximum, minimum, and mean at different subbands were computed and classification was done using linear classifier. The performance of classifier was determined in terms of specificity, sensitivity, and accuracy. The overall accuracy was 84.2%. In the case of seizure onset detection, the database used is CHB-MIT scalp EEG database. Along with wavelet based features, interquartile range (IQR) and mean absolute deviation (MAD) without wavelet decomposition were extracted. Latency was used to study the performance of seizure onset detection. Classifier gave a sensitivity of 98.5% with an average latency of 1.76 seconds. PMID:24616892

Ahammad, Nabeel; Fathima, Thasneem; Joseph, Paul

2014-01-01

360

Nonlinear analysis of EEG signals at different mental states  

PubMed Central

Background The EEG (Electroencephalogram) is a representative signal containing information about the condition of the brain. The shape of the wave may contain useful information about the state of the brain. However, the human observer can not directly monitor these subtle details. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the EEG signal parameters, extracted and analyzed using computers, are highly useful in diagnostics. This work discusses the effect on the EEG signal due to music and reflexological stimulation. Methods In this work, nonlinear parameters like Correlation Dimension (CD), Largest Lyapunov Exponent (LLE), Hurst Exponent (H) and Approximate Entropy (ApEn) are evaluated from the EEG signals under different mental states. Results The results obtained show that EEG to become less complex relative to the normal state with a confidence level of more than 85% due to stimulation. Conclusions It is found that the measures are significantly lower when the subjects are under sound or reflexologic stimulation as compared to the normal state. The dimension increases with the degree of the cognitive activity. This suggests that when the subjects are under sound or reflexologic stimuli, the number of parallel functional processes active in the brain is less and the brain goes to a more relaxed state PMID:15023233

Natarajan, Kannathal; Acharya U, Rajendra; Alias, Fadhilah; Tiboleng, Thelma; Puthusserypady, Sadasivan K

2004-01-01

361

Alpha-1 Panniculitis  

MedlinePLUS

... medical conditions, panniculitis can have many underlying causes. Alpha-1 Antitrypsin Deficiency (Alpha-1) is one of those causes. There ... the rarest of the well-known complications of Alpha-1 Antitrypsin Deficiency. In those with Alpha-1 (called Alphas), the ...

362

Modulation of spontaneous alpha brain rhythms using low-intensity transcranial direct-current stimulation  

PubMed Central

Transcranial direct-current stimulation (tDCS) is a form of neurostimulation in which a constant, low current is delivered directly to the brain area of interest by small electrodes. The overall aim of this study was to examine and monitor the modulation of brain activity by electroencephalogram (EEG) in the frequency domain during tDCS in the resting state. To this end, we considered the modulation of spontaneous EEG to be a marker of the perturbation that was induced through the direct current (1.5 mA for 15 min). In all conditions (anodal, cathodal, and sham), an active electrode was placed over the right posterior parietal cortex, and a reference electrode was placed on the ipsilateral deltoid muscle. The EEG was recorded using a 64-channel system. The effect of tDCS was limited to the alpha rhythm, and the anodal stimulation significantly affected the alpha rhythm, whereas the cathodal stimulation did not elicit any modifications. Further, we observed modulation of alpha activity in areas that were stimulated directly through tDCS and in anterior noncontiguous areas. Finally, the anodal effect peaked 7.5 min after stimulation and decreased gradually over time. Our study demonstrates that in the resting brain, monocephalic anodal tDCS over posterior parietal areas alters ongoing brain activity, specifically in the alpha band rhythm. Our data can be used to fine-tune tDCS protocols in neurorehabilitation settings. PMID:24027517

Spitoni, Grazia F.; Cimmino, Rocco L.; Bozzacchi, Chiara; Pizzamiglio, Luigi; Di Russo, Francesco

2013-01-01

363

EEG analysis based on wavelet-spectral entropy for epileptic seizures detection  

Microsoft Academic Search

The electroencephalogram (EEG) is the brain signal containing valuable information about the normal or epileptic state of the brain. In this paper a discrete wavelet-spectral entropy (SEN) method is presented for epileptic seizures detection through the analysis of EEGs and EEG sub-bands. The EEG signal is decomposed by discrete wavelet transform into its sub-bands and is characterized by spectral entropy

Ahmad Mirzaei; Ahmad Ayatollahi; Parisa Gifani; Leili Salehi

2010-01-01

364

SlimQuick(TM) - associated hepatotoxicity in a woman with alpha-1 antitrypsin heterozygosity  

PubMed Central

Green tea (Camellia sinensis)-associated hepatotoxicity is reported. However, the presence of alpha-1 antitrypsin MZ phenotype as a predisposing factor to green tea-associated drug-induced liver injury (DILI) is unknown. A previously healthy woman with alpha-1 antitrypsin MZ phenotype who took SlimQuick™, an herbal supplement containing green tea extract, developed severe hepatotoxicity requiring corticosteroid treatment. Green tea-associated hepatotoxicity is reviewed and alpha-1 antitrypsin MZ phenotype as a predisposing factor to green tea-associated DILI is discussed. Liver biopsy demonstrated marked inflammation with necrosis suggestive of toxic injury with diffuse alpha-1 antitrypsin globule deposition on immunostaining. Corticosteroid therapy resulted in rapid clinical improvement. Alpha-1 antitrypsin MZ phenotype may increase vulnerability to herbal hepatotoxicity. PMID:22567188

Weinstein, Douglas H; Twaddell, William S; Raufman, Jean-Pierre; Philosophe, Benjamin; Mindikoglu, Ayse L

2012-01-01

365

Towards a unified understanding of event-related changes in the EEG: the firefly model of synchronization through cross-frequency phase modulation.  

PubMed

Although event-related potentials (ERPs) are widely used to study sensory, perceptual and cognitive processes, it remains unknown whether they are phase-locked signals superimposed upon the ongoing electroencephalogram (EEG) or result from phase-alignment of the EEG. Previous attempts to discriminate between these hypotheses have been unsuccessful but here a new test is presented based on the prediction that ERPs generated by phase-alignment will be associated with event-related changes in frequency whereas evoked-ERPs will not. Using empirical mode decomposition (EMD), which allows measurement of narrow-band changes in the EEG without predefining frequency bands, evidence was found for transient frequency slowing in recognition memory ERPs but not in simulated data derived from the evoked model. Furthermore, the timing of phase-alignment was frequency dependent with the earliest alignment occurring at high frequencies. Based on these findings, the Firefly model was developed, which proposes that both evoked and induced power changes derive from frequency-dependent phase-alignment of the ongoing EEG. Simulated data derived from the Firefly model provided a close match with empirical data and the model was able to account for i) the shape and timing of ERPs at different scalp sites, ii) the event-related desynchronization in alpha and synchronization in theta, and iii) changes in the power density spectrum from the pre-stimulus baseline to the post-stimulus period. The Firefly Model, therefore, provides not only a unifying account of event-related changes in the EEG but also a possible mechanism for cross-frequency information processing. PMID:23049827

Burgess, Adrian P

2012-01-01

366

A Low-Noise, Low-Power EEG Acquisition Node for Scalable Brain-Machine Interfaces  

E-print Network

A Low-Noise, Low-Power EEG Acquisition Node for Scalable Brain-Machine Interfaces Thomas J systems offer a versatile, non-invasive window on the brain's spatiotem- poral activity for many of EEG recording by reducing the form factor, power drain and signal fanout of the EEG acquisition node

Cauwenberghs, Gert

367

The EEG in early diagnosis of the Angelman (Happy Puppet) syndrome  

Microsoft Academic Search

An EEG study has been carried out on 19 children (including siblings in 3 families) with clinical features of Angelman syndrome. The age at time of the first EEG ranged from 11 months to 11 years with the majority under 5 years. Six children had no history of seizures at the time of the first EEG. One or more of

S. G. Boyd; A. Harden; M. A. Patton

1988-01-01

368

Automated ECG artefact reduction in EEG as a preprocessing step for neonatal seizure detection  

E-print Network

Automated ECG artefact reduction in EEG as a preprocessing step for neonatal seizure detection W and automated analysis of the EEG much more difficult. This paper addresses the problem of removing the ECG EEG of newborn children with perinatal asphyxia. Results show that ICA is able to extract the ECG from

369

Eigenvector Methods for Analysis of Human PPG, ECG and EEG Signals  

Microsoft Academic Search

This paper presents eigenvector methods for analysis of the photoplethysmogram (PPG), eigenvector methods for analysis of human PPG, ECG and EEG signals Electrocardiogram (ECG), electroencephalogram (EEG) signals recorded in order to examine the effects of pulsed electromagnetic field (PEMF) at extremely low frequency (ELF) upon the human electrophysiological signal behavior. The features representing the PPG, ECG, EEG signals were obtained

Elif Derya Übeyli; Dean Cvetkovic; Irena Cosic

2007-01-01

370

Expression of Hemispheric Asymmetry and Psychological Type in the EEG Traveling Wave  

Microsoft Academic Search

Spontaneous EEG patterns were recorded from 16 derivations in the parieto-occipital area over 2 min for subjects in the resting state with the eyes closed. Further, computer analysis of the current pattern of EEG phase relationships between all derivations was conducted, followed by visualization in real time of the trajectory and velocity of the traveling EEG wave as a computerized

D. R. Belov; S. F. Kolodyazhnyi; N. Yu. Smit

2004-01-01

371

Classification of EEG during imagined mental tasks by forecasting with Elman Recurrent Neural Networks  

Microsoft Academic Search

The ability to classify EEG recorded while a subject performs varying imagined mental tasks may lay the foundation for building usable Brain-Computer Interfaces as well as improve the performance of EEG analysis software used in clinical settings. Although a number of research groups have produced EEG classifiers, these methods have not yet reached a level of performance that is acceptable

Elliott M. Forney; Charles W. Anderson

2011-01-01

372

EEG Estimates of Cognitive Workload and Engagement Predict Math Problem Solving Outcomes  

ERIC Educational Resources Information Center

In the present study, the authors focused on the use of electroencephalography (EEG) data about cognitive workload and sustained attention to predict math problem solving outcomes. EEG data were recorded as students solved a series of easy and difficult math problems. Sequences of attention and cognitive workload estimates derived from the EEG

Beal, Carole R.; Galan, Federico Cirett

2012-01-01

373

An EEG (electroencephalogram) recording system with carbon wire electrodes for simultaneous EEG-fMRI (functional magnetic resonance imaging) recording  

PubMed Central

Simultaneous EEG-fMRI (Electroencephalography-functional Magnetic Resonance Imaging) recording provides a means for acquiring high temporal resolution electrophysiological data and high spatial resolution metabolic data of the brain in the same experimental runs. Carbon wire electrodes (not metallic EEG electrodes with carbon wire leads) are suitable for simultaneous EEG-fMRI recording, because they cause less RF (radio-frequency) heating and susceptibility artifacts than metallic electrodes. These characteristics are especially desirable for recording the EEG in high field MRI scanners. Carbon wire electrodes are also comfortable to wear during long recording sessions. However, carbon electrodes have high electrode-electrolyte potentials compared to widely used Ag/AgCl (silver/silver-chloride) electrodes, which may cause slow voltage drifts. This paper introduces a prototype EEG recording system with carbon wire electrodes and a circuit that suppresses the slow voltage drift. The system was tested for the voltage drift, RF heating, susceptibility artifact, and impedance, and was also evaluated in a simultaneous ERP (event-related potential)-fMRI experiment. PMID:18588913

Negishi, Michiro; Abildgaard, Mark; Laufer, Ilan; Nixon, Terry; Constable, Robert Todd

2008-01-01

374

EEG predictors of covert vigilant attention  

NASA Astrophysics Data System (ADS)

Objective. The present study addressed the question whether neurophysiological signals exhibit characteristic modulations preceding a miss in a covert vigilant attention task which mimics a natural environment in which critical stimuli may appear in the periphery of the visual field. Approach. Subjective, behavioural and encephalographic (EEG) data of 12 participants performing a modified Mackworth Clock task were obtained and analysed offline. The stimulus consisted of a pointer performing regular ticks in a clockwise sequence across 42 dots arranged in a circle. Participants were requested to covertly attend to the pointer and press a response button as quickly as possible in the event of a jump, a rare and random event. Main results. Significant increases in response latencies and decreases in the detection rates were found as a function of time-on-task, a characteristic effect of sustained attention tasks known as the vigilance decrement. Subjective sleepiness showed a significant increase over the duration of the experiment. Increased activity in the ?-frequency range (8-14 Hz) was observed emerging and gradually accumulating 10 s before a missed target. Additionally, a significant gradual attenuation of the P3 event-related component was found to antecede misses by 5 s. Significance. The results corroborate recent findings that behavioural errors are presaged by specific neurophysiological activity and demonstrate that lapses of attention can be predicted in a covert setting up to 10 s in advance reinforcing the prospective use of brain-computer interface (BCI) technology for the detection of waning vigilance in real-world scenarios. Combining these findings with real-time single-trial analysis from BCI may pave the way for cognitive states monitoring systems able to determine the current, and predict the near-future development of the brain's attentional processes.

Martel, Adrien; Dähne, Sven; Blankertz, Benjamin

2014-06-01

375

Liver and Alpha-1  

MedlinePLUS

... CSL Behring Grifols The mission of the Alpha-1 Foundation is to provide the leadership and resources ... information, visit: www.alpha-1foundation.org. The Alpha-1 Association is the leading national patient membership organization ...

376

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

... from the NHLBI on Twitter. What Is Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (an-tee-TRIP-sin) deficiency, or AAT ... as it relates to lung disease. Overview Alpha-1 antitrypsin, also called AAT, is a protein made ...

377

Neural decoding of expressive human movement from scalp electroencephalography (EEG).  

PubMed

Although efforts to characterize human movement through electroencephalography (EEG) have revealed neural activities unique to limb control that can be used to infer movement kinematics, it is still unknown the extent to which EEG can be used to discern the expressive qualities that influence such movements. In this study we used EEG and inertial sensors to record brain activity and movement of five skilled and certified Laban Movement Analysis (LMA) dancers. Each dancer performed whole body movements of three Action types: movements devoid of expressive qualities ("Neutral"), non-expressive movements while thinking about specific expressive qualities ("Think"), and enacted expressive movements ("Do"). The expressive movement qualities that were used in the "Think" and "Do" actions consisted of a sequence of eight Laban Effort qualities as defined by LMA-a notation system and language for describing, visualizing, interpreting and documenting all varieties of human movement. We used delta band (0.2-4 Hz) EEG as input to a machine learning algorithm that computed locality-preserving Fisher's discriminant analysis (LFDA) for dimensionality reduction followed by Gaussian mixture models (GMMs) to decode the type of Action. We also trained our LFDA-GMM models to classify all the possible combinations of Action Type and Laban Effort quality (giving a total of 17 classes). Classification accuracy rates were 59.4 ± 0.6% for Action Type and 88.2 ± 0.7% for Laban Effort quality Type. Ancillary analyses of the potential relations between the EEG and movement kinematics of the dancer's body, indicated that motion-related artifacts did not significantly influence our classification results. In summary, this research demonstrates that EEG has valuable information about the expressive qualities of movement. These results may have applications for advancing the understanding of the neural basis of expressive movements and for the development of neuroprosthetics to restore movements. PMID:24782734

Cruz-Garza, Jesus G; Hernandez, Zachery R; Nepaul, Sargoon; Bradley, Karen K; Contreras-Vidal, Jose L

2014-01-01

378

Ictal video-EEG analysis of infantile neuroaxonal dystrophy.  

PubMed

A 4-year-old boy with infantile neuroaxonal dystrophy (INAD) showed gradual deterioration from age 9 months with seizure development at age approximately 36 months. Sural nerve biopsy performed at age 42 months confirmed INAD. The seizure, recorded by video-EEG, consisted of a series of symmetrical tonic spasms of both upper extremities after a prodrome period of staring and akinesis. Each spasm had phonation, and episodic autonomic symptoms such as hypertension and flushing of the face occurred throughout the seizure. Ictal EEG with each tonic spasm, showed diffuse 1-s, irregular sharp and high-voltage slow wave complexes followed by desynchronization. PMID:8082629

Wakai, S; Asanuma, H; Hayasaka, H; Kawamoto, Y; Sueoka, H; Ishikawa, Y; Minami, R; Chiba, S

1994-01-01

379

Nonlinear aspects of the EEG during sleep in children  

NASA Astrophysics Data System (ADS)

Electroencephalograph (EEG) analysis enables the dynamic behavior of the brain to be examined. If the behavior is nonlinear then nonlinear tools can be used to glean information on brain behavior, and aid in the diagnosis of sleep abnormalities such as obstructive sleep apnea syndrome (OSAS). In this paper the sleep EEGs of a set of normal children and children with mild OSAS are evaluated for nonlinear brain behaviour. We found that there were differences in the nonlinearity of the brain behaviour between different sleep stages, and between the two groups of children.

Berryman, Matthew J.; Coussens, Scott W.; Pamula, Yvonne; Kennedy, Declan; Lushington, Kurt; Shalizi, Cosma; Allison, Andrew; Martin, A. James; Saint, David; Abbott, Derek

2005-05-01

380

EEG preprocessing for synchronization estimation and epilepsy lateralization.  

PubMed

The global framework of this paper is the synchronization analysis in EEG recordings. Two main objectives are pursued: the evaluation of the synchronization estimation for lateralization purposes in epileptic EEGs and the evaluation of the effect of the preprocessing (artifact and noise cancelling by blind source separation, wavelet denoising and classification) on the synchronization analysis. We propose a new global synchronization index, based on the classical cross power spectrum, estimated for each cerebral hemisphere. After preprocessing, the proposed index is able to correctly lateralize the epileptic zone in over 90% of the cases. PMID:22255468

Vélez-Pérez, H; Romo-Vázquez, R; Ranta, R; Louis-Dorr, V; Maillard, L

2011-01-01

381

Auto-antibodies and seizures: clinical and EEG findings.  

PubMed

Epilepsy is a common disorder that may be caused by wide ranging etiologies. Historically a significant number of people with epilepsy have idiopathic epilepsy without a definitive etiology. More recently, auto-antibodies have been discovered to be associated with numerous conditions affecting the nervous system, including epilepsy. With this increased understanding of the potential for immune-based etiologies for epilepsy it is important to recognize the associated EEG patterns in such cases. This report presents the EEG findings in epilepsy patients with one or more auto-antibodies. PMID:24783749

Drazkowski, Joseph; Hoerth, Matthew; Tapsell, Lisa; Noe, Katherine; Shih, Jerry; Sirven, Joseph; Tatum, William O

2014-03-01

382

Down Syndrome: Cognitive Phenotype  

ERIC Educational Resources Information Center

Down syndrome is the most prevalent cause of intellectual impairment associated with a genetic anomaly, in this case, trisomy of chromosome 21. It affects both physical and cognitive development and produces a characteristic phenotype, although affected individuals vary considerably with respect to severity of specific impairments. Studies…

Silverman, Wayne

2007-01-01

383

Finding a Phenotype  

NSDL National Science Digital Library

Students can examine all manner of plant phenotypes during their investigation, from leaf size and shape to flower number and color to UV light sensitivity to "time to bolt," meaning the amount of time after planting until the plants develop stems or bolts.

Dr. Erin L Dolan (Virginia Tech Biochemistry)

2009-08-24

384

Color combinations of visual display terminal (VDT) icon on user preferences and EEG response.  

PubMed

This study explored the effects of color combinations and polarity on user preferences and EEG responses using an icon design for a visual display terminal. 72 college students (M=24.5 yr., SD=2.3 yr.) were tested. The seven color combinations of top 16% with rating scores (5-point scale) over 3.60 almost always included black or white as a target or background, including white-on-black, red-on-black, yellow-on-black, blue-on-white, and black-on-white; the other two preferred color combinations were yellow-on-blue and blue-on-yellow. The eight color combinations of the bottom 16% with rating scores under 2.38 almost always included green, turquoise, or purple as a target or background. Negative image polarity (higher luminance color image shown on a lower luminance color background) was preferred over positive image polarity (lower luminance color image shown on a higher luminance color background) by the subjects. The theta and alpha band power in the right hemisphere were greater than those in the left hemisphere during the experiment. There seemed to be no linear correlation between the rating scores of subjective preferences and brain wave power of theta and alpha bands, so the possibility of using brain wave power to measure subjective preference is questionable. PMID:20499552

Ko, Ya-Hsien; Shen, I-Hsuan; Lee, Der-Song

2010-04-01

385

The transliminal brain at rest: baseline EEG, unusual experiences, and access to unconscious mental activity.  

PubMed

Transliminality reflects individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness. Individuals high in transliminality possess characteristics such as magical ideation, belief in the paranormal, and creative personality traits, and also report the occurrence of manic/mystic experiences. The goal of the present research was to determine if resting brain activity differs for individuals high versus low in transliminality. We compared baseline EEG recordings (eyes-closed) between individuals high versus low in transliminality, assessed using The Revised Transliminality Scale of Lange et al. (2000). Identifying reliable differences at rest between high- and low-transliminality individuals would support a predisposition for transliminality-related traits. Individuals high in transliminality exhibited lower alpha, beta, and gamma power than individuals low in transliminality over left posterior association cortex and lower high alpha, low beta, and gamma power over the right superior temporal region. In contrast, when compared to individuals low in transliminality, individuals high in transliminality exhibited greater gamma power over the frontal-midline region. These results are consistent with prior research reporting reductions in left temporal/parietal activity, as well as the desynchronization of right temporal activity in schizotypy and related schizophrenia spectrum disorders. Further, differences between high- and low-transliminality groups extend existing theories linking altered hemispheric asymmetries in brain activity to a predisposition toward schizophrenia, paranormal beliefs, and unusual experiences. PMID:18814870

Fleck, Jessica I; Green, Deborah L; Stevenson, Jennifer L; Payne, Lisa; Bowden, Edward M; Jung-Beeman, Mark; Kounios, John

2008-01-01

386

Sample Entropy Tracks Changes in EEG Power Spectrum With Sleep State and Aging  

PubMed Central

The regularity of EEG signals was compared between middle-aged (47.2 ± 2.0 yrs) and elderly (78.4 ± 3.8 yrs) female subjects in Wake (W), NREM stages 2 and 3 (S2, S3), and REM. Signals from C3A2 leads of healthy normal subjects, acquired from polysomnograms obtained from the Sleep Heart Health Study, were analyzed using both Sample Entropy (SaEn) and power spectral analysis (delta, theta, alpha, and beta frequency band powers). SaEn changed systematically and significantly (p<0.001) with sleep state in both age groups, following the relationships W > REM > S2 > S3. SaEn was found to be negatively correlated with delta power and positively correlated with beta power. Small changes in SaEn appear to reflect changes in spectral content rather than changes in regularity of the signal. A better predictor of SaEn than the frequency band powers was the logarithm of the power ratio (alpha+beta)/(delta+theta). Thus, SaEn appears to reflect the balance between sleep-promoting and alertness-promoting mechanisms. SaEn of the elderly was larger than that of middle-aged subjects in S2 (p=0.029) and REM (p=0.001), suggesting that cortical state is shifted towards alertness in elderly subjects in these sleep states compared to middle-aged. PMID:19590434

Bruce, Eugene N.; Bruce, Margaret C.; Vennelaganti, Swetha

2009-01-01

387

The Transliminal Brain at Rest: Baseline EEG, Unusual Experiences, and Access to Unconscious Mental Activity  

PubMed Central

Transliminality reflects individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness. Individuals high in transliminality possess characteristics such as magical ideation, belief in the paranormal, and creative personality traits, and also report the occurrence of manic/mystic experiences. The goal of the present research was to determine if resting brain activity differs for individuals high versus low in transliminality. We compared baseline EEG recordings (eyes-closed) between individuals high versus low in transliminality, assessed using The Revised Transliminality Scale of Lange et al. (2000). Identifying reliable differences at rest between high- and low-transliminality individuals would support a predisposition for transliminality-related traits. Individuals high in transliminality exhibited lower alpha, beta, and gamma power than individuals low in transliminality over left posterior association cortex and lower high alpha, low beta, and gamma power over the right superior temporal region. In contrast, when compared to individuals low in transliminality, individuals high in transliminality exhibited greater gamma power over the frontal-midline region. These results are consistent with prior research reporting reductions in left temporal/parietal activity, as well as the desynchronization of right temporal activity in schizotypy and related schizophrenia spectrum disorders. Further, differences between high- and low-transliminality groups extend existing theories linking altered hemispheric asymmetries in brain activity to a predisposition toward schizophrenia, paranormal beliefs, and unusual experiences. PMID:18814870

Fleck, Jessica I.; Green, Deborah L.; Stevenson, Jennifer L.; Payne, Lisa; Bowden, Edward M.; Jung-Beeman, Mark; Kounios, John

2008-01-01

388

EEG classification approach based on the extreme learning machine and wavelet transform.  

PubMed

Automatic detection and classification of electroencephalogram (EEG) epileptic activity aid diagnosis and relieve the heavy workload of doctors. This article presents a new EEG classification approach based on the extreme learning machine (ELM) and wavelet transform (WT). First, the WT is used to extract useful features when certain scales cover abnormal components of the EEG. Second, the ELM algorithm is used to train a single hidden layer of feedforward neural network (SLFN) features. Finally, the SLFN is tested with interictal and ictal EEGs. The experiments demonstrated that the proposed approach achieved a satisfactory classification rate of 99.25% for interictal and ictal EEGs. PMID:22715486

Yuan, Qi; Zhou, Weidong; Zhang, Jing; Li, Shufang; Cai, Dongmei; Zeng, Yanjun

2012-04-01

389

Massage and music therapies attenuate frontal EEG asymmetry in depressed adolescents.  

PubMed

EEG asymmetry, specifically greater relative right frontal activation, is associated with negative affect. Depressed adults show stable patterns of this asymmetry. The present study assessed the effects of massage therapy and music therapy on frontal EEG asymmetry in depressed adolescents. Thirty adolescents with greater relative right frontal EEG activation and symptoms of depression were given either massage therapy (n = 14) or music therapy (n = 16). EEG was recorded for three-minute periods before, during, and after therapy. Frontal EEG asymmetry was significantly attenuated during and after the massage and music sessions. PMID:10658860

Jones, N A; Field, T

1999-01-01

390

Detection of concealed information by P3 and frontal EEG asymmetry.  

PubMed

Psychophysiological detection of deception has seen increased attention in both research and applied settings. In this field, the most scientifically validated paradigm is the Concealed Information Test (CIT). The CIT does not directly deal with whether a participant is lying, but examines whether a participant recognizes a critical relevant detail, inferred by differences in physiological responses between critical and non-critical items. Although event-related potential (ERP) approaches to the CIT have shown high accuracy, a combination of measures might improve the test's performance. We thus assessed whether a new CIT index, frontal EEG asymmetry that is supposed to reflect differences in approach/withdrawal motivation, would prove useful. Nineteen participants were asked to steal one item in a mock crime, and were then administered two CITs while concealing the stolen item. One CIT included the stolen item (i.e., guilty condition), whereas the other CIT did not (i.e., innocent condition). In the guilty condition, the concealed stolen item elicited greater relative left frontal alpha activity (indicative of relative right frontal cortical activity) as compared to the other items, suggesting that the recognition of the concealed item might have induced withdrawal motivation. Although the discrimination between guilty and innocent conditions by the asymmetry score alone was not as good as that by the ERP P3 index, combining the asymmetry score and P3 improved the detection performance significantly. The results suggest that the frontal EEG asymmetry can be used as a new measure in the CIT that provides additional information beyond that captured by the traditional ERP index. PMID:23370285

Matsuda, Izumi; Nittono, Hiroshi; Allen, John J B

2013-03-14

391

Single trial prediction of self-paced reaching directions from EEG signals.  

PubMed

Early detection of movement intention could possibly minimize the delays in the activation of neuroprosthetic devices. As yet, single trial analysis using non-invasive approaches for understanding such movement preparation remains a challenging task. We studied the feasibility of predicting movement directions in self-paced upper limb center-out reaching tasks, i.e., spontaneous movements executed without an external cue that can better reflect natural motor behavior in humans. We reported results of non-invasive electroencephalography (EEG) recorded from mild stroke patients and able-bodied participants. Previous studies have shown that low frequency EEG oscillations are modulated by the intent to move and therefore, can be decoded prior to the movement execution. Motivated by these results, we investigated whether slow cortical potentials (SCPs) preceding movement onset can be used to classify reaching directions and evaluated the performance using 5-fold cross-validation. For able-bodied subjects, we obtained an average decoding accuracy of 76% (chance level of 25%) at 62.5 ms before onset using the amplitude of on-going SCPs with above chance level performances between 875 to 437.5 ms prior to onset. The decoding accuracy for the stroke patients was on average 47% with their paretic arms. Comparison of the decoding accuracy across different frequency ranges (i.e., SCPs, delta, theta, alpha, and gamma) yielded the best accuracy using SCPs filtered between 0.1 to 1 Hz. Across all the subjects, including stroke subjects, the best selected features were obtained mostly from the fronto-parietal regions, hence consistent with previous neurophysiological studies on arm reaching tasks. In summary, we concluded that SCPs allow the possibility of single trial decoding of reaching directions at least 312.5 ms before onset of reach. PMID:25136290

Lew, Eileen Y L; Chavarriaga, Ricardo; Silvoni, Stefano; Millán, José Del R

2014-01-01

392

EEG feature comparison and classification of simple and compound limb motor imagery  

PubMed Central

Background Motor imagery can elicit brain oscillations in Rolandic mu rhythm and central beta rhythm, both originating in the sensorimotor cortex. In contrast with simple limb motor imagery, less work was reported about compound limb motor imagery which involves several parts of limbs. The goal of this study was to investigate the differences of the EEG patterns between simple limb motor imagery and compound limb motor imagery, and discuss the separability of multiple types of mental tasks. Methods Ten subjects participated in the experiment involving three tasks of simple limb motor imagery (left hand, right hand, feet), three tasks of compound limb motor imagery (both hands, left hand combined with right foot, right hand combined with left foot) and rest state. Event-related spectral perturbation (ERSP), power spectral entropy (PSE) and spatial distribution coefficient were adopted to analyze these seven EEG patterns. Then three algorithms of modified multi-class common spatial patterns (CSP) were used for feature extraction and classification was implemented by support vector machine (SVM). Results The induced event-related desynchronization (ERD) affects more components within both alpha and beta bands resulting in more broad ERD bands at electrode positions C3, Cz and C4 during left/right hand combined with contralateral foot imagery, whose PSE values are significant higher than that of simple limb motor imagery. From the topographical distribution, simultaneous imagination of upper limb and contralateral lower limb certainly contributes to the activation of more areas on cerebral cortex. Classification result shows that multi-class stationary Tikhonov regularized CSP (Multi-sTRCSP) outperforms other two multi-class CSP methods, with the highest accuracy of 84% and mean accuracy of 70%. Conclusions The work implies that there exist the separable differences between simple limb motor imagery and compound limb motor imagery, which can be utilized to build a multimodal classification paradigm in motor imagery based brain-computer interface (BCI) systems. PMID:24119261

2013-01-01

393

Special Space Curves Characterized by det({\\alpha}^{(3)}, {\\alpha}^{(4)},{\\alpha}^{(5)})=0  

E-print Network

In this study, by using the facts that det({\\alpha}^{(1)}, {\\alpha}^{(2)}, {\\alpha}^{(3)}) = 0 characterizes plane curve, and det({\\alpha}^{(2)}, {\\alpha}^{(3)}, {\\alpha}^{(4)}) = 0 does a curve of constant slope, we give the special space curves that are characterized by det({\\alpha}^{(3)}, {\\alpha}^{(4)}, {\\alpha}^{(5)}) = 0, in different approaches. We find that the space curve is Salkowski if and only if det({\\alpha}^{(3)}, {\\alpha}^{(4)}, {\\alpha}^{(5)}) = 0. The approach we used in this paper is useful in understanding the role of the curves that are characterized by det({\\alpha}^{(3)}, {\\alpha}^{(4)}, {\\alpha}^{(5)})=0 in differential geometry.

Yayali, Yusuf

2012-01-01

394

EFFECT OF DAYTIME EXERCISE ON SLEEP EEG AND SUBJECTIVE SLEEP  

Microsoft Academic Search

This study was designed to assess the effects of daytime physical exercise on the quality of objective and subjective sleep by examining all-night sleep EEGs. The subjects were five male students, aged 19 to 20 years, who were in the habit of performing regular daytime exercise. The sleep polygraphic parameters in this study were sleep stage time as a percentage

Y. Sasazawa; T. Kawada; Y. Kiryu

1997-01-01

395

EEG coherence in post-LSD visual hallucinations  

Microsoft Academic Search

LSD use in certain individuals may result in chronic visual hallucinations, a DSM-IV syndrome known as hallucinogen persisting perception disorder (HPPD). We studied 38 HPPD subjects with a mean of 9.7 years of persistent visual hallucinations and 33 control subjects. Measures of local and medium distance EEG spectral coherence were calculated from all subjects. Coherence, a measure of spectral similarity

Henry David Abraham; Frank Hopkins Duffy

2001-01-01

396

Telemetric EEG and the Rat: A Guide For Neuroscientists  

PubMed Central

Telemetric EEG in the rat’s brain has been used for experiments which tests the effects of an antiepileptic compound on it’s antiseizures activity. A simple classification correlating epileptiform discharge and Racine’s behavioral activity is discussed. PMID:23613643

Abdullah, Jafri Malin; Rafiqul Islam, Mohammad

2012-01-01

397

Health Instruction Packages: Medical Technologies--EEG, Radiology, & Biomedical Photography.  

ERIC Educational Resources Information Center

Text, illustrations, and exercises are utilized in this set of four learning modules to instruct medical technology students in a variety of job-related skills. The first module, "EEG Technology: Measurement Technique of the 'International 10-20 System'" by Dorothea Brittenham, describes a procedure used by electroencephalograph technicians to…

Brittenham, Dorothea; And Others

398

Music increases frontal EEG coherence during verbal learning  

Microsoft Academic Search

Anecdotal and some empirical evidence suggests that music can enhance learning and memory. However, the mechanisms by which music modulates the neural activity associated with learning and memory remain largely unexplored. We evaluated coherent frontal oscillations in the electroencephalogram (EEG) while subjects were engaged in a modified version of Rey's Auditory Verbal Learning Test (AVLT). Subjects heard either a spoken

David A. Peterson; Michael H. Thaut

2007-01-01

399

EEG and MEG source localization using recursively applied (RAP) MUSIC  

Microsoft Academic Search

The multiple signal characterization (MUSIC) algorithm locates multiple asynchronous dipolar sources from electroencephalography (EEG) and magnetoencephalography (MEG) data. A signal subspace is estimated from the data, then the algorithm scans a single dipole model through a three-dimensional head volume and computes projections onto this subspace. To locate the sources, the user must search the head volume for local peaks in

John C. Mosher; Richard M. Leahy

1996-01-01

400

Information theoretic approach to quantify causal neural interactions from EEG  

Microsoft Academic Search

In neurophysiology, it is important to quantify the causal neural interactions and infer the underlying complex networks from neurophysiological recordings such as electroen-cephalogram (EEG). Existing methods such as Granger causality are model dependent and thus cannot quantify nonlinear dependencies. In this paper, directed information (DI) is used to quantify the causality of the interactions and time-lagged directed information is proposed

Ying Liu; Selin Aviyente

2010-01-01

401

Achievement Motivation and Learning: A Gamma-Band EEG  

E-print Network

Achievement Motivation and Learning: A Gamma-Band EEG Study Jennifer Mesrie And Dr. Jennifer Mangels #12;Self Theories about Intelligence "There are qualitatively different motivational frameworks Theorists Incremental Theorists · Learning goals ­ seeking to develop ability · Performance goals ­ seeking

Champagne, Frances A.

402

EEG-based brain dynamics of driving distraction  

Microsoft Academic Search

Distraction during driving has been recognized as a significant cause of traffic accidents. The aim of this study is to investigate Electroencephalography (EEG) -based brain dynamics in response to driving distraction. To study human cognition under specific driving tasks in a simulated driving experiment, this study utilized two simulated events including unexpected car deviations and mathematics questions. The raw data

Chin-Teng Lin; Shi-An Chen; Li-Wei Ko; Yu-Kai Wang

2011-01-01

403

EEG analysis of frontal hemispheric asymmetry for learning styles  

Microsoft Academic Search

Learning style had become an importance researched subject for understanding how individual learns. Apart from that, personality traits such as emotions, moods and self- motivation of the learners were also being actively studied. In this research, the learners' learning style and their personality traits were investigated by Electroencephalogram (EEG) Frontal Asymmetry. First, The participants (N=41) learning styles were classified using

Nazre bin Abdul Rashid; Mohd. Nasir Taib; Sahrim Lias; Norizam Sulaiman

2011-01-01

404

Automatic and Direct Identification of Blink Components from Scalp EEG  

PubMed Central

Eye blink is an important and inevitable artifact during scalp electroencephalogram (EEG) recording. The main problem in EEG signal processing is how to identify eye blink components automatically with independent component analysis (ICA). Taking into account the fact that the eye blink as an external source has a higher sum of correlation with frontal EEG channels than all other sources due to both its location and significant amplitude, in this paper, we proposed a method based on correlation index and the feature of power distribution to automatically detect eye blink components. Furthermore, we prove mathematically that the correlation between independent components and scalp EEG channels can be translating directly from the mixing matrix of ICA. This helps to simplify calculations and understand the implications of the correlation. The proposed method doesn't need to select a template or thresholds in advance, and it works without simultaneously recording an electrooculography (EOG) reference. The experimental results demonstrate that the proposed method can automatically recognize eye blink components with a high accuracy on entire datasets from 15 subjects. PMID:23959240

Kong, Wanzeng; Zhou, Zhanpeng; Hu, Sanqing; Zhang, Jianhai; Babiloni, Fabio; Dai, Guojun

2013-01-01

405

Spatio-temporal coupling of EEG signals in epilepsy  

Microsoft Academic Search

Approximately 1% of the world's population suffer from epileptic seizures throughout their lives that mostly come without sign or warning. Thus, epilepsy is the most common chronical disorder of the neurological system. In the past decades, the problem of detecting a pre-seizure state in epilepsy using EEG signals has been addressed in many contributions by various authors over the past

Vanessa Senger; Jens Müller; Ronald Tetzlaff

2011-01-01

406

Spatio-temporal EEG source localization using simulated annealing  

Microsoft Academic Search

The estimation of multiple dipole parameters in spatio-temporal source modeling (STSM) of electroencephalographic (EEG) data is a difficult nonlinear optimization problem due to multiple local minima in the cost function. A straightforward iterative optimization approach to such a problem is very susceptible to being trapped in a local minimum, thereby resulting in incorrect estimates of the dipole parameters. Here, the

Deepak Khosla; Manbir Singh; Manuel Don

1997-01-01

407

Distraction-related EEG dynamics in virtual reality driving simulation  

Microsoft Academic Search

Driver distraction has been recognized as a significant cause of traffic incidents. Therefore, the aim of this study was to investigate electroencephalography (EEG) dynamics in response to distraction during driving. To study human cognition under specific driving task, we used virtual reality (VR) based driving simulation to simulate events including unexpected car deviations and mathematics questions (math) in real driving.

Chin-teng Lin; Hong-zhang Lin; Tzai-wen Chiu; Chih-feng Chao; Yu-chieh Chen; Sheng-fu Liang; Li-wei Ko

2008-01-01

408

Effects of robot therapy for demented patients evaluated by EEG  

Microsoft Academic Search

Robot therapy for demented patients was conducted at a cranial nerve clinic. Two therapeutic seal robots, Paro, were introduced there. This paper describes the results of this experiment. DIMENSION (diagnosis method of neuronal dysfunction) was used to analyze recorded patient's EEG before and after 20 minutes of robot therapy. Questionnaire concerning impression of seal robots was also conducted. The results

Kazuyoshi Wada; T. Shibata; Toshimitsu Musha; S. Kimura

2005-01-01

409

Multimodal Functional Neuroimaging: Integrating Functional MRI and EEG/MEG  

PubMed Central

Noninvasive functional neuroimaging, as an important tool for basic neuroscience research and clinical diagnosis, continues to face the need of improving the spatial and temporal resolution. While existing neuroimaging modalities might approach their limits in imaging capability mostly due to fundamental as well as technical reasons, it becomes increasingly attractive to integrate multiple complementary modalities in an attempt to significantly enhance the spatiotemporal resolution that cannot be achieved by any modality individually. Electrophysiological and hemodynamic/metabolic signals reflect distinct but closely coupled aspects of the underlying neural activity. Combining fMRI and EEG/MEG data allows us to study brain function from different perspectives. In this review, we start with an overview of the physiological origins of EEG/MEG and fMRI, as well as their fundamental biophysics and imaging principles; it is followed by a review of major progresses in understanding and modeling the neurovascular coupling, methodologies for the fMRI-EEG/MEG integration and EEG-fMRI simultaneous recording; finally, important remaining issues and perspectives (including brain connectivity imaging) are summarized. PMID:20634915

He, Bin; Liu, Zhongming

2010-01-01

410

Motor imagery EEG Recognition based on Biomimetic Pattern Recognition  

Microsoft Academic Search

This paper improves Biomimetic Pattern Recognition based on Hyper Sausage Neuron and applies it in the study of Motor Imagery EEG recognition. The paper uses the datasets from previous Brain-Computer Interface Competitions to test the accuracy and efficiency of the results, and compares them with those of SVM and BP. The results show that: with sufficient training set, the performance

Kai Xu; Yan Wu

2010-01-01

411

Bayesian Approach to the Ill-posed EEG Inverse Problem  

E-print Network

.imm.dtu.dk #12;Summary Scalp recorded EEG signals are caused by neural currents in the brain. The brain currents describing the neural current distribution and the signal noise. Bayes theorem enables detailed analytical. Finally some real data is analyzed using the algorithms. #12;ii #12;Preface I think and think for months

412

The EEG and Incidence of Epilepsy in Down's Syndrome.  

ERIC Educational Resources Information Center

It was found, among other things, that neither the presence of congenital heart disease, nor diabetes, nor intercurrent illness appeared to have any effect on the development of seizures. The age groups with the lowest proportion of EEG abnormalities were 25-34 years (48.7 percent abnormal) and 35-44 years (54.1 percent abnormal). (Author/DLS)

Tangye, Sheila R.

1979-01-01

413

Converging Evidence of Linear Independent Components in EEG Lucas Parra  

E-print Network

the assumptions of non-Gaussian, non-stationary, or non-white independent sources. If the linear independence separation (BSS), electroen- cephalography (EEG), non-Gaussian, non-white, non- stationary. I. INTRODUCTION] assume that the sources have a colored spectrum. Yet other algorithms are available that assume non

Parra, Lucas C.

414

Imaging Methods for MEG\\/EEG Inverse Problem  

Microsoft Academic Search

Recovering electrical activity of the brain from MEG\\/EEG measurements is known as the MEEG inverse prob- lem. It is an ill-posed problem in several senses. One is that there is further less data observed than data to recover. One way to address this issue is to search for regular solutions. We present here a framework for applying image processing filtering

Maureen Clerc; Renaud Keriven

2005-01-01

415

Review on solving the inverse problem in EEG source analysis  

Microsoft Academic Search

In this primer, we give a review of the inverse problem for EEG source localization. This is intended for the researchers new in the field to get insight in the state-of-the-art techniques used to find approximate solutions of the brain sources giving rise to a scalp potential recording. Furthermore, a review of the performance results of the different techniques is

Roberta Grech; Tracey Cassar; Joseph Muscat; Kenneth P Camilleri; Simon G Fabri; Michalis Zervakis; Petros Xanthopoulos; Vangelis Sakkalis; Bart Vanrumste

2008-01-01

416

Hemimegalencephaly: Clinical, EEG, neuroimaging, and IMP-SPECT correlation  

SciTech Connect

Iofetamine-single photon emission computed tomography (IMP-SPECT) was performed on 2 girls (5 1/2 and 6 years of age) with histories of intractable seizures, developmental delay, and unilateral hemiparesis secondary to hemimegalencephaly. Electroencephalography (EEG) revealed frequent focal discharges in 1 patient, while a nearly continuous burst suppression pattern over the malformed hemisphere was recorded in the other. IMP-SPECT demonstrated a good correlation with neuroimaging studies. In spite of the different EEG patterns, which had been proposed to predict contrasting clinical outcomes, both IMP-SPECT scans disclosed a similar decrease in tracer uptake in the malformed hemisphere. These results are consistent with the pattern of decreased tracer uptake found in other interictal studies of focal seizures without cerebral malformations. In view of recent recommendations for hemispherectomy in these patients, we suggest that the IMP-SPECT scan be used to compliment EEG as a method to define the extent of abnormality which may be more relevant to long-term prognosis than EEG alone.

Konkol, R.J.; Maister, B.H.; Wells, R.G.; Sty, J.R. (Medical College of Wisconsin, Milwaukee (USA))

1990-11-01