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Sample records for high-density eeg study

  1. Regional Reductions in Sleep Electroencephalography Power in Obstructive Sleep Apnea: A High-Density EEG Study

    PubMed Central

    Jones, Stephanie G.; Riedner, Brady A.; Smith, Richard F.; Ferrarelli, Fabio; Tononi, Giulio; Davidson, Richard J.; Benca, Ruth M.

    2014-01-01

    Study Objectives: Obstructive sleep apnea (OSA) is associated with significant alterations in neuronal integrity resulting from either hypoxemia and/or sleep loss. A large body of imaging research supports reductions in gray matter volume, alterations in white matter integrity and resting state activity, and functional abnormalities in response to cognitive challenge in various brain regions in patients with OSA. In this study, we used high-density electroencephalography (hdEEG), a functional imaging tool that could potentially be used during routine clinical care, to examine the regional distribution of neural activity in a non-clinical sample of untreated men and women with moderate/severe OSA. Design: Sleep was recorded with 256-channel EEG in relatively healthy subjects with apnea-hypopnea index (AHI) > 10, as well as age-, sex-, and body mass index-matched controls selected from a research population initially recruited for a study on sleep and meditation. Setting: Sleep laboratory. Patients or Participants: Nine subjects with AHI > 10 and nine matched controls. Interventions: N/A. Measurements and Results: Topographic analysis of hdEEG data revealed a broadband reduction in EEG power in a circumscribed region overlying the parietal cortex in OSA subjects. This parietal reduction in neural activity was present, to some extent, across all frequency bands in all stages and episodes of nonrapid eye movement sleep. Conclusion: This investigation suggests that regional deficits in electroencephalography (EEG) power generation may be a useful clinical marker for neural disruption in obstructive sleep apnea, and that high-density EEG may have the sensitivity to detect pathological cortical changes early in the disease process. Citation: Jones SG; Riedner BA; Smith RF; Ferrarelli F; Tononi G; Davidson RJ; Benca RM. Regional reductions in sleep electroencephalography power in obstructive sleep apnea: a high-density EEG study. SLEEP 2014;37(2):399-407. PMID:24497668

  2. Regional reductions in sleep electroencephalography power in obstructive sleep apnea: a high-density EEG study.

    PubMed

    Jones, Stephanie G; Riedner, Brady A; Smith, Richard F; Ferrarelli, Fabio; Tononi, Giulio; Davidson, Richard J; Benca, Ruth M

    2014-02-01

    Obstructive sleep apnea (OSA) is associated with significant alterations in neuronal integrity resulting from either hypoxemia and/or sleep loss. A large body of imaging research supports reductions in gray matter volume, alterations in white matter integrity and resting state activity, and functional abnormalities in response to cognitive challenge in various brain regions in patients with OSA. In this study, we used high-density electroencephalography (hdEEG), a functional imaging tool that could potentially be used during routine clinical care, to examine the regional distribution of neural activity in a non-clinical sample of untreated men and women with moderate/severe OSA. Sleep was recorded with 256-channel EEG in relatively healthy subjects with apnea-hypopnea index (AHI) > 10, as well as age-, sex-, and body mass index-matched controls selected from a research population initially recruited for a study on sleep and meditation. Sleep laboratory. Nine subjects with AHI > 10 and nine matched controls. N/A. Topographic analysis of hdEEG data revealed a broadband reduction in EEG power in a circumscribed region overlying the parietal cortex in OSA subjects. This parietal reduction in neural activity was present, to some extent, across all frequency bands in all stages and episodes of nonrapid eye movement sleep. This investigation suggests that regional deficits in electroencephalography (EEG) power generation may be a useful clinical marker for neural disruption in obstructive sleep apnea, and that high-density EEG may have the sensitivity to detect pathological cortical changes early in the disease process.

  3. Scalp and Source Power Topography in Sleepwalking and Sleep Terrors: A High-Density EEG Study

    PubMed Central

    Castelnovo, Anna; Riedner, Brady A.; Smith, Richard F.; Tononi, Giulio; Boly, Melanie; Benca, Ruth M.

    2016-01-01

    Study Objectives: To examine scalp and source power topography in sleep arousals disorders (SADs) using high-density EEG (hdEEG). Methods: Fifteen adult subjects with sleep arousal disorders (SADs) and 15 age- and gender-matched good sleeping healthy controls were recorded in a sleep laboratory setting using a 256 channel EEG system. Results: Scalp EEG analysis of all night NREM sleep revealed a localized decrease in slow wave activity (SWA) power (1–4 Hz) over centro-parietal regions relative to the rest of the brain in SADs compared to good sleeping healthy controls. Source modelling analysis of 5-minute segments taken from N3 during the first half of the night revealed that the local decrease in SWA power was prominent at the level of the cingulate, motor, and sensori-motor associative cortices. Similar patterns were also evident during REM sleep and wake. These differences in local sleep were present in the absence of any detectable clinical or electrophysiological sign of arousal. Conclusions: Overall, results suggest the presence of local sleep differences in the brain of SADs patients during nights without clinical episodes. The persistence of similar topographical changes in local EEG power during REM sleep and wakefulness points to trait-like functional changes that cross the boundaries of NREM sleep. The regions identified by source imaging are consistent with the current neurophysiological understanding of SADs as a disorder caused by local arousals in motor and cingulate cortices. Persistent localized changes in neuronal excitability may predispose affected subjects to clinical episodes. Citation: Castelnovo A, Riedner BA, Smith RF, Tononi G, Boly M, Benca RM. Scalp and source power topography in sleepwalking and sleep terrors: a high-density EEG study. SLEEP 2016;39(10):1815–1825. PMID:27568805

  4. Scalp and Source Power Topography in Sleepwalking and Sleep Terrors: A High-Density EEG Study.

    PubMed

    Castelnovo, Anna; Riedner, Brady A; Smith, Richard F; Tononi, Giulio; Boly, Melanie; Benca, Ruth M

    2016-10-01

    To examine scalp and source power topography in sleep arousals disorders (SADs) using high-density EEG (hdEEG). Fifteen adult subjects with sleep arousal disorders (SADs) and 15 age- and gender-matched good sleeping healthy controls were recorded in a sleep laboratory setting using a 256 channel EEG system. Scalp EEG analysis of all night NREM sleep revealed a localized decrease in slow wave activity (SWA) power (1-4 Hz) over centro-parietal regions relative to the rest of the brain in SADs compared to good sleeping healthy controls. Source modelling analysis of 5-minute segments taken from N3 during the first half of the night revealed that the local decrease in SWA power was prominent at the level of the cingulate, motor, and sensori-motor associative cortices. Similar patterns were also evident during REM sleep and wake. These differences in local sleep were present in the absence of any detectable clinical or electrophysiological sign of arousal. Overall, results suggest the presence of local sleep differences in the brain of SADs patients during nights without clinical episodes. The persistence of similar topographical changes in local EEG power during REM sleep and wakefulness points to trait-like functional changes that cross the boundaries of NREM sleep. The regions identified by source imaging are consistent with the current neurophysiological understanding of SADs as a disorder caused by local arousals in motor and cingulate cortices. Persistent localized changes in neuronal excitability may predispose affected subjects to clinical episodes.

  5. Altered slow wave activity in major depressive disorder with hypersomnia: a high density EEG pilot study.

    PubMed

    Plante, David T; Landsness, Eric C; Peterson, Michael J; Goldstein, Michael R; Wanger, Tim; Guokas, Jeff J; Tononi, Giulio; Benca, Ruth M

    2012-03-31

    Hypersomnolence in major depressive disorder (MDD) plays an important role in the natural history of the disorder, but the basis of hypersomnia in MDD is poorly understood. Slow wave activity (SWA) has been associated with sleep homeostasis, as well as sleep restoration and maintenance, and may be altered in MDD. Therefore, we conducted a post-hoc study that utilized high density electroencephalography (hdEEG) to test the hypothesis that MDD subjects with hypersomnia (HYS+) would have decreased SWA relative to age- and sex-matched MDD subjects without hypersomnia (HYS-) and healthy controls (n=7 for each group). After correction for multiple comparisons using statistical non-parametric mapping, HYS+ subjects demonstrated significantly reduced parieto-occipital all-night SWA relative to HYS- subjects. Our results suggest hypersomnolence may be associated with topographic reductions in SWA in MDD. Further research using an adequately powered prospective design is indicated to confirm these findings. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. High density scalp EEG in frontal lobe epilepsy.

    PubMed

    Feyissa, Anteneh M; Britton, Jeffrey W; Van Gompel, Jamie; Lagerlund, Terrance L; So, Elson; Wong-Kisiel, Lilly C; Cascino, Gregory C; Brinkman, Benjamin H; Nelson, Cindy L; Watson, Robert; Worrell, Gregory A

    2017-01-01

    Localization of seizures in frontal lobe epilepsy using the 10-20 system scalp EEG is often challenging because neocortical seizure can spread rapidly, significant muscle artifact, and the suboptimal spatial resolution for seizure generators involving mesial frontal lobe cortex. Our aim in this study was to determine the value of visual interpretation of 76 channel high density EEG (hdEEG) monitoring (10-10 system) in patients with suspected frontal lobe epilepsy, and to evaluate concordance with MRI, subtraction ictal SPECT co-registered to MRI (SISCOM), conventional EEG, and intracranial EEG (iEEG). We performed a retrospective cohort study of 14 consecutive patients who underwent hdEEG monitoring for suspected frontal lobe seizures. The gold standard for localization was considered to be iEEG. Concordance of hdEEG findings with MRI, subtraction ictal SPECT co-registered to MRI (SISCOM), conventional 10-20 EEG, and iEEG as well as correlation of hdEEG localization with surgical outcome were examined. hdEEG localization was concordant with iEEG in 12/14 and was superior to conventional EEG 3/14 (p<0.01) and SISCOM 3/12 (p<0.01). hdEEG correctly lateralized seizure onset in 14/14 cases, compared to 9/14 (p=0.04) cases with conventional EEG. Seven patients underwent surgical resection, of whom five were seizure free. hdEEG monitoring should be considered in patients with suspected frontal epilepsy requiring localization of epileptogenic brain. hdEEG may assist in developing a hypothesis for iEEG monitoring and could potentially augment EEG source localization. Published by Elsevier B.V.

  7. Early Left Parietal Activity Elicited by Direct Gaze: A High-Density EEG Study

    PubMed Central

    Burra, Nicolas; Kerzel, Dirk; George, Nathalie

    2016-01-01

    Gaze is one of the most important cues for human communication and social interaction. In particular, gaze contact is the most primary form of social contact and it is thought to capture attention. A very early-differentiated brain response to direct versus averted gaze has been hypothesized. Here, we used high-density electroencephalography to test this hypothesis. Topographical analysis allowed us to uncover a very early topographic modulation (40–80 ms) of event-related responses to faces with direct as compared to averted gaze. This modulation was obtained only in the condition where intact broadband faces–as opposed to high-pass or low-pas filtered faces–were presented. Source estimation indicated that this early modulation involved the posterior parietal region, encompassing the left precuneus and inferior parietal lobule. This supports the idea that it reflected an early orienting response to direct versus averted gaze. Accordingly, in a follow-up behavioural experiment, we found faster response times to the direct gaze than to the averted gaze broadband faces. In addition, classical evoked potential analysis showed that the N170 peak amplitude was larger for averted gaze than for direct gaze. Taken together, these results suggest that direct gaze may be detected at a very early processing stage, involving a parallel route to the ventral occipito-temporal route of face perceptual analysis. PMID:27880776

  8. "Cuts in Action": A High-Density EEG Study Investigating the Neural Correlates of Different Editing Techniques in Film.

    PubMed

    Heimann, Katrin S; Uithol, Sebo; Calbi, Marta; Umiltà, Maria A; Guerra, Michele; Gallese, Vittorio

    2016-11-24

    In spite of their striking differences with real-life perception, films are perceived and understood without effort. Cognitive film theory attributes this to the system of continuity editing, a system of editing guidelines outlining the effect of different cuts and edits on spectators. A major principle in this framework is the 180° rule, a rule recommendation that, to avoid spectators' attention to the editing, two edited shots of the same event or action should not be filmed from angles differing in a way that expectations of spatial continuity are strongly violated. In the present study, we used high-density EEG to explore the neural underpinnings of this rule. In particular, our analysis shows that cuts and edits in general elicit early ERP component indicating the registration of syntactic violations as known from language, music, and action processing. However, continuity edits and cuts-across the line differ from each other regarding later components likely to be indicating the differences in spatial remapping as well as in the degree of conscious awareness of one's own perception. Interestingly, a time-frequency analysis of the occipital alpha rhythm did not support the hypothesis that such differences in processing routes are mainly linked to visual attention. On the contrary, our study found specific modulations of the central mu rhythm ERD as an indicator of sensorimotor activity, suggesting that sensorimotor networks might play an important role. We think that these findings shed new light on current discussions about the role of attention and embodied perception in film perception and should be considered when explaining spectators' different experience of different kinds of cuts.

  9. How the motor-cortex distinguishes among letters, unknown symbols and scribbles. A high density EEG study.

    PubMed

    Heimann, Katrin; Umilta, Maria Alessandra; Gallese, Vittorio

    2013-11-01

    Previous research has reported that the perception of written language symbols activates the cortical motor hand representation of the dominant hemisphere also found to be activated during the writing of these symbols. It has been suggested that such motor activation supports reading. Nevertheless, the precise circumstances leading to such activation are still unknown. For instance, several studies suggested that motor activation necessarily depends on specific sensory-motor experience with the stimuli. Some results, however, also indicated that untrained stimuli can elicit the response. Moreover, due to the methods used so far, little is known about the temporal course of the motor activity. Our study explored these open questions using high-density EEG. We measured central alpha event-related desynchronization (ERD) as a marker of cortical motor activation during the observation of Roman letters (alphabet of participants' mother language), Chinese characters (not familiar to participants), and scribbles. Our results show that the cortical motor system is activated during the perception of all three stimuli in both hemispheres, with ERD stronger in the left (dominant) hemisphere. A significant difference of ERD time-course was observed in the left hemisphere between the observation of symbols (letters and characters) and scribbles. Scribbles elicited significantly faster resynchronization of central alpha than symbols. We suggest that ERD results are due to recognizing all stimuli as traces of hand gestures. Furthermore, differences in ERD found between symbols and scribbles might depend either on visuo-motor training, separating symbols from scribbles, or on stimuli specific features marking their status as either language symbols or scribbles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Adaptation in human somatosensory cortex as a model of sensory memory construction: a study using high-density EEG.

    PubMed

    Bradley, Claire; Joyce, Niamh; Garcia-Larrea, Luis

    2016-01-01

    Adaptation in sensory cortices has been seen as a mechanism allowing the creation of transient memory representations. Here we tested the adapting properties of early responses in human somatosensory areas SI and SII by analysing somatosensory-evoked potentials over the very first repetitions of a stimulus. SI and SII generators were identified by well-defined scalp potentials and source localisation from high-density 128-channel EEG. Earliest responses (~20 ms) from area 3b in the depth of the post-central gyrus did not show significant adaptation to stimuli repeated at 300 ms intervals. In contrast, responses around 45 ms from the crown of the gyrus (areas 1 and 2) rapidly lessened to a plateau and abated at the 20th stimulation, and activities from SII in the parietal operculum at ~100 ms displayed strong adaptation with a steady amplitude decrease from the first repetition. Although responses in both SI (1-2) and SII areas showed adapting properties and hence sensory memory capacities, evidence of sensory mismatch detection has been demonstrated only for responses reflecting SII activation. This may index the passage from an early form of sensory storage in SI to more operational memory codes in SII, allowing the prediction of forthcoming input and the triggering of a specific signal when such input differs from the previous sequence. This is consistent with a model whereby the length of temporal receptive windows increases with progression in the cortical hierarchy, in parallel with the complexity and abstraction of neural representations.

  11. Attention modulation regulates both motor and non-motor performance: a high-density EEG study in Parkinson's disease.

    PubMed

    Perfetti, B; Moisello, C; Lanzafame, S; Varanese, S; Landsness, E C; Onofrj, M; Di Rocco, A; Tononi, G; Ghilardi, M F

    2010-09-01

    We have previously shown that, in early stages of Parkinson's disease (PD), patients with higher reaction times are also more impaired in visual sequence learning, suggesting that movement preparation shares resources with the learning of visuospatial sequences. Here, we ascertained whether, in patients with PD, the pattern of the neural correlates of attentional processes of movement planning predict sequence learning and working memory abilities. High density Electroencephalography (EEG, 256 electrodes) was recorded in 19 patients with PD performing reaching movements in a choice reaction time paradigm. Patients were also tested with Digit Span and performed a visuomotor sequence learning task that has an important declarative learning component. We found that attenuation of alpha/beta oscillatory activity before the stimulus presentation in frontoparietal regions significantly correlated with reaction time in the choice reaction time task, similarly to what we had previously found in normal subjects. In addition, such activity significantly predicted the declarative indices of sequence learning and the scores in the Digit Span task. These findings suggest that some motor and non motor PD signs might have common neural bases, and thus, might have a similar response to the same behavioral therapy. In addition, these results might help in designing and testing the efficacy of novel rehabilitative approaches to improve specific aspects of motor performance in PD and other neurological disorders.

  12. Understanding Actions of Others: The Electrodynamics of the Left and Right Hemispheres. A High-Density EEG Neuroimaging Study

    PubMed Central

    Ortigue, Stephanie; Sinigaglia, Corrado; Rizzolatti, Giacomo; Grafton, Scott T.

    2010-01-01

    Background When we observe an individual performing a motor act (e.g. grasping a cup) we get two types of information on the basis of how the motor act is done and the context: what the agent is doing (i.e. grasping) and the intention underlying it (i.e. grasping for drinking). Here we examined the temporal dynamics of the brain activations that follow the observation of a motor act and underlie the observer's capacity to understand what the agent is doing and why. Methodology/Principal Findings Volunteers were presented with two-frame video-clips. The first frame (T0) showed an object with or without context; the second frame (T1) showed a hand interacting with the object. The volunteers were instructed to understand the intention of the observed actions while their brain activity was recorded with a high-density 128-channel EEG system. Visual event-related potentials (VEPs) were recorded time-locked with the frame showing the hand-object interaction (T1). The data were analyzed by using electrical neuroimaging, which combines a cluster analysis performed on the group-averaged VEPs with the localization of the cortical sources that give rise to different spatio-temporal states of the global electrical field. Electrical neuroimaging results revealed four major steps: 1) bilateral posterior cortical activations; 2) a strong activation of the left posterior temporal and inferior parietal cortices with almost a complete disappearance of activations in the right hemisphere; 3) a significant increase of the activations of the right temporo-parietal region with simultaneously co-active left hemispheric sources, and 4) a significant global decrease of cortical activity accompanied by the appearance of activation of the orbito-frontal cortex. Conclusions/Significance We conclude that the early striking left hemisphere involvement is due to the activation of a lateralized action-observation/action execution network. The activation of this lateralized network mediates the

  13. Intraindividual Increase of Homeostatic Sleep Pressure Across Acute and Chronic Sleep Loss: A High-Density EEG Study.

    PubMed

    Maric, Angelina; Lustenberger, Caroline; Werth, Esther; Baumann, Christian R; Poryazova, Rositsa; Huber, Reto

    2017-09-01

    To compare intraindividually the effects of acute sleep deprivation (ASD) and chronic sleep restriction (CSR) on the homeostatic increase in slow wave activity (SWA) and to relate it to impairments in basic cognitive functioning, that is, vigilance. The increase in SWA after ASD (40 hours of wakefulness) and after CSR (seven nights with time in bed restricted to 5 hours per night) relative to baseline sleep was assessed in nine healthy, male participants (age = 18-26 years) by high-density electroencephalography. The SWA increase during the initial part of sleep was compared between the two conditions of sleep loss. The increase in SWA was related to the increase in lapses of vigilance in the psychomotor vigilance task (PVT) during the preceding days. While ASD induced a stronger increase in initial SWA than CSR, the increase was globally correlated across the two conditions in most electrodes. The increase in initial SWA was positively associated with the increase in PVT lapses. The individual homeostatic response in SWA is globally preserved across acute and chronic sleep loss, that is, individuals showing a larger increase after ASD also do so after CSR and vice versa. Furthermore, the increase in SWA is globally correlated to vigilance impairments after sleep loss over both conditions. Thus, the increase in SWA might therefore provide a physiological marker for individual differences in performance impairments after sleep loss.

  14. A high-density EEG study of differences between three high speeds of simulated forward motion from optic flow in adult participants

    PubMed Central

    Vilhelmsen, Kenneth; van der Weel, F. R. (Ruud); van der Meer, Audrey L. H.

    2015-01-01

    A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in response to high speeds of simulated forward motion. Participants were shown an optic flow pattern consisting of a virtual road with moving poles at either side of it, simulating structured forward motion at different driving speeds (25, 50, and 75 km/h) with a static control condition between each motion condition. Significant differences in N2 latencies and peak amplitudes between the three speeds of visual motion were found in parietal channels of interest P3 and P4. As motion speed increased, peak latency increased while peak amplitude decreased which might indicate that higher driving speeds are perceived as more demanding resulting in longer latencies, and as fewer neurons in the motion sensitive areas of the adult brain appear to be attuned to such high visual speeds this could explain the observed inverse relationship between speed and amplitude. In addition, significant differences between alpha de-synchronizations for forward motion and alpha synchronizations in the static condition were found in the parietal midline (PM) source. It was suggested that the alpha de-synchronizations reflect an activated state related to the visual processing of simulated forward motion, whereas the alpha synchronizations in response to the static condition reflect a deactivated resting period. PMID:26578903

  15. Moving mirrors: a high-density EEG study investigating the effect of camera movements on motor cortex activation during action observation.

    PubMed

    Heimann, Katrin; Umiltà, Maria Alessandra; Guerra, Michele; Gallese, Vittorio

    2014-09-01

    Action execution-perception links (mirror mechanism) have been repeatedly suggested to play crucial roles in social cognition. Remarkably, the designs of most studies exploring this topic so far excluded even the simplest traces of social interaction, such as a movement of the observer toward another individual. This study introduces a new design by investigating the effects of camera movements, possibly simulating the observer's own approaching movement toward the scene. We conducted a combined high-density EEG and behavioral study investigating motor cortex activation during action observation measured by event-related desynchronization and resynchronization (ERD/ERS) of the mu rhythm. Stimuli were videos showing a goal-related hand action filmed while using the camera in four different ways: filming from a fixed position, zooming in on the scene, approaching the scene by means of a dolly, and approaching the scene by means of a steadycam. Results demonstrated a consistently stronger ERD of the mu rhythm for videos that were filmed while approaching the scene with a steadycam. Furthermore, videos in which the zoom was applied reliably demonstrated a stronger rebound. A rating task showed that videos in which the camera approached the scene were felt as more involving and the steadycam was most able to produce a visual experience close to the one of a human approaching the scene. These results suggest that filming technique predicts time course specifics of ERD/ERS during action observation with only videos simulating the natural vision of a walking human observer eliciting a stronger ERD than videos filmed from a fixed position. This demonstrates the utility of ecologically designed studies for exploring social cognition.

  16. Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla.

    PubMed

    Foged, Mette Thrane; Lindberg, Ulrich; Vakamudi, Kishore; Larsson, Henrik B W; Pinborg, Lars H; Kjær, Troels W; Fabricius, Martin; Svarer, Claus; Ozenne, Brice; Thomsen, Carsten; Beniczky, Sándor; Paulson, Olaf B; Posse, Stefan

    2017-01-01

    Concurrent EEG and fMRI is increasingly used to characterize the spatial-temporal dynamics of brain activity. However, most studies to date have been limited to conventional echo-planar imaging (EPI). There is considerable interest in integrating recently developed high-speed fMRI methods with high-density EEG to increase temporal resolution and sensitivity for task-based and resting state fMRI, and for detecting interictal spikes in epilepsy. In the present study using concurrent high-density EEG and recently developed high-speed fMRI methods, we investigate safety of radiofrequency (RF) related heating, the effect of EEG on cortical signal-to-noise ratio (SNR) in fMRI, and assess EEG data quality. The study compared EPI, multi-echo EPI, multi-band EPI and multi-slab echo-volumar imaging pulse sequences, using clinical 3 Tesla MR scanners from two different vendors that were equipped with 64- and 256-channel MR-compatible EEG systems, respectively, and receive only array head coils. Data were collected in 11 healthy controls (3 males, age range 18-70 years) and 13 patients with epilepsy (8 males, age range 21-67 years). Three of the healthy controls were scanned with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual analysis by a trained expert in the 64 channel EEG data (7 healthy controls, 13 patients). RF induced heating at the surface of the EEG electrodes during a 30-minute scan period with stable temperature prior to scanning did not exceed 1.0° C with either EEG system and any of the pulse sequences used in this study. There was no significant decrease in cortical SNR due to the presence of the EEG cap (p > 0.05). No significant differences in the visually analyzed EEG data quality were found between EEG

  17. Automated detection and labeling of high-density EEG electrodes from structural MR images

    NASA Astrophysics Data System (ADS)

    Marino, Marco; Liu, Quanying; Brem, Silvia; Wenderoth, Nicole; Mantini, Dante

    2016-10-01

    Objective. Accurate knowledge about the positions of electrodes in electroencephalography (EEG) is very important for precise source localizations. Direct detection of electrodes from magnetic resonance (MR) images is particularly interesting, as it is possible to avoid errors of co-registration between electrode and head coordinate systems. In this study, we propose an automated MR-based method for electrode detection and labeling, particularly tailored to high-density montages. Approach. Anatomical MR images were processed to create an electrode-enhanced image in individual space. Image processing included intensity non-uniformity correction, background noise and goggles artifact removal. Next, we defined a search volume around the head where electrode positions were detected. Electrodes were identified as local maxima in the search volume and registered to the Montreal Neurological Institute standard space using an affine transformation. This allowed the matching of the detected points with the specific EEG montage template, as well as their labeling. Matching and labeling were performed by the coherent point drift method. Our method was assessed on 8 MR images collected in subjects wearing a 256-channel EEG net, using the displacement with respect to manually selected electrodes as performance metric. Main results. Average displacement achieved by our method was significantly lower compared to alternative techniques, such as the photogrammetry technique. The maximum displacement was for more than 99% of the electrodes lower than 1 cm, which is typically considered an acceptable upper limit for errors in electrode positioning. Our method showed robustness and reliability, even in suboptimal conditions, such as in the case of net rotation, imprecisely gathered wires, electrode detachment from the head, and MR image ghosting. Significance. We showed that our method provides objective, repeatable and precise estimates of EEG electrode coordinates. We hope our work

  18. Only Three Fingers Write, but the Whole Brain Works†: A High-Density EEG Study Showing Advantages of Drawing Over Typing for Learning

    PubMed Central

    van der Meer, Audrey L. H.; van der Weel, F. R. (Ruud)

    2017-01-01

    Are different parts of the brain active when we type on a keyboard as opposed to when we draw visual images on a tablet? Electroencephalogram (EEG) was used in young adults to study brain electrical activity as they were typing or describing in words visually presented PictionaryTM words using a keyboard, or as they were drawing pictures of the same words on a tablet using a stylus. Analyses of temporal spectral evolution (time-dependent amplitude changes) were performed on EEG data recorded with a 256-channel sensor array. We found that when drawing, brain areas in the parietal and occipital regions showed event related desynchronization activity in the theta/alpha range. Existing literature suggests that such oscillatory neuronal activity provides the brain with optimal conditions for learning. When describing the words using the keyboard, upper alpha/beta/gamma range activity in the central and frontal brain regions were observed, especially during the ideation phase. However, since this activity was highly synchronized, its relation to learning remains unclear. We concluded that because of the benefits for sensory-motor integration and learning, traditional handwritten notes are preferably combined with visualizations (e.g., small drawings, shapes, arrows, symbols) to facilitate and optimize learning. PMID:28536546

  19. Only Three Fingers Write, but the Whole Brain Works: A High-Density EEG Study Showing Advantages of Drawing Over Typing for Learning.

    PubMed

    van der Meer, Audrey L H; van der Weel, F R Ruud

    2017-01-01

    Are different parts of the brain active when we type on a keyboard as opposed to when we draw visual images on a tablet? Electroencephalogram (EEG) was used in young adults to study brain electrical activity as they were typing or describing in words visually presented Pictionary(TM) words using a keyboard, or as they were drawing pictures of the same words on a tablet using a stylus. Analyses of temporal spectral evolution (time-dependent amplitude changes) were performed on EEG data recorded with a 256-channel sensor array. We found that when drawing, brain areas in the parietal and occipital regions showed event related desynchronization activity in the theta/alpha range. Existing literature suggests that such oscillatory neuronal activity provides the brain with optimal conditions for learning. When describing the words using the keyboard, upper alpha/beta/gamma range activity in the central and frontal brain regions were observed, especially during the ideation phase. However, since this activity was highly synchronized, its relation to learning remains unclear. We concluded that because of the benefits for sensory-motor integration and learning, traditional handwritten notes are preferably combined with visualizations (e.g., small drawings, shapes, arrows, symbols) to facilitate and optimize learning.

  20. Comparison of the spatial resolution of source imaging techniques in high-density EEG and MEG.

    PubMed

    Hedrich, T; Pellegrino, G; Kobayashi, E; Lina, J M; Grova, C

    2017-06-13

    The present study aims at evaluating and comparing electrical and magnetic distributed source imaging methods applied to high-density Electroencephalography (hdEEG) and Magnetoencephalography (MEG) data. We used resolution matrices to characterize spatial resolution properties of Minimum Norm Estimate (MNE), dynamic Statistical Parametric Mapping (dSPM), standardized Low-Resolution Electromagnetic Tomography (sLORETA) and coherent Maximum Entropy on the Mean (cMEM, an entropy-based technique). The resolution matrix provides information of the Point Spread Functions (PSF) and of the Crosstalk functions (CT), this latter being also called source leakage, as it reflects the influence of a source on its neighbors. The spatial resolution of the inverse operators was first evaluated theoretically and then with real data acquired using electrical median nerve stimulation on five healthy participants. We evaluated the Dipole Localization Error (DLE) and the Spatial Dispersion (SD) of each PSF and CT map. cMEM showed the smallest spatial spread (SD) for both PSF and CT maps, whereas localization errors (DLE) were similar for all methods. Whereas cMEM SD values were lower in MEG compared to hdEEG, the other methods slightly favored hdEEG over MEG. In real data, cMEM provided similar localization error and significantly less spatial spread than other methods for both MEG and hdEEG. Whereas both MEG and hdEEG provided very accurate localizations, all the source imaging methods actually performed better in MEG compared to hdEEG according to all evaluation metrics, probably due to the higher signal-to-noise ratio of the data in MEG. Our overall results show that all investigated methods provide similar localization errors, suggesting very accurate localization for both MEG and hdEEG when similar number of sensors are considered for both modalities. Intrinsic properties of source imaging methods as well as their behavior for well-controlled tasks, suggest an overall better

  1. Pain catastrophizing and cortical responses in amputees with varying levels of phantom limb pain: a high-density EEG brain-mapping study.

    PubMed

    Vase, Lene; Egsgaard, Line Lindhardt; Nikolajsen, Lone; Svensson, Peter; Jensen, Troels Staehelin; Arendt-Nielsen, Lars

    2012-05-01

    Pain catastrophizing has been associated with phantom limb pain, but so far the cortical processes and the brain regions involved in this relationship have not been investigated. It was therefore tested whether catastrophizing was related to (1) spontaneous pain, (2) somatosensory activity and (3) cortical responses in phantom limb pain patients. The cortical responses were investigated via electroencephalography (EEG) as it has a high temporal resolution which may be ideal for investigating especially the attentional and hypervigilance aspect of catastrophizing to standardized acute stimuli. Eighteen upper limb amputees completed the pain catastrophizing scale. Patients' spontaneous pain levels (worst and average pain, numerical rating scales) and thresholds to electrical stimulation (sensory detection and VRS2: intense but not painful) were determined. Non-painful electrical stimuli were applied to both the affected and non-affected arm, while high-resolution (128 channels) EEG signals were recorded. Catastrophizing accounted for significant amounts of the variance in relation to spontaneous pain, especially worst pain (64.1%), and it was significantly associated with thresholds. At the affected side, catastrophizing was significantly related to the power RMS of the N/P135 dipole located in the area around the secondary somatosensory cortex which has been shown to be associated with arousal and expectations. These findings corroborate the attentional model of pain catastrophizing by indicating that even non-painful stimuli are related to enhanced attention to and negative expectations of stimuli, and they suggest that memory processes may be central to understanding the link between catastrophizing and pain.

  2. Cortical Source Analysis of High-Density EEG Recordings in Children

    PubMed Central

    Bathelt, Joe; O'Reilly, Helen; de Haan, Michelle

    2014-01-01

    EEG is traditionally described as a neuroimaging technique with high temporal and low spatial resolution. Recent advances in biophysical modelling and signal processing make it possible to exploit information from other imaging modalities like structural MRI that provide high spatial resolution to overcome this constraint1. This is especially useful for investigations that require high resolution in the temporal as well as spatial domain. In addition, due to the easy application and low cost of EEG recordings, EEG is often the method of choice when working with populations, such as young children, that do not tolerate functional MRI scans well. However, in order to investigate which neural substrates are involved, anatomical information from structural MRI is still needed. Most EEG analysis packages work with standard head models that are based on adult anatomy. The accuracy of these models when used for children is limited2, because the composition and spatial configuration of head tissues changes dramatically over development3.  In the present paper, we provide an overview of our recent work in utilizing head models based on individual structural MRI scans or age specific head models to reconstruct the cortical generators of high density EEG. This article describes how EEG recordings are acquired, processed, and analyzed with pediatric populations at the London Baby Lab, including laboratory setup, task design, EEG preprocessing, MRI processing, and EEG channel level and source analysis.  PMID:25045930

  3. Longitudinal study of preterm and full-term infants: High-density EEG analyses of cortical activity in response to visual motion.

    PubMed

    Agyei, Seth B; van der Weel, F R Ruud; van der Meer, Audrey L H

    2016-04-01

    Electroencephalogram (EEG) was used to investigate brain electrical activity of full-term and preterm infants at 4 and 12 months of age as a functional response mechanism to structured optic flow and random visual motion. EEG data were recorded with an array of 128-channel sensors. Visual evoked potentials (VEPs) and temporal spectral evolution (TSE, time-dependent amplitude changes) were analysed. VEP results showed a significant improvement in full-term infants' latencies with age for forwards and reversed optic flow but not random visual motion. Full-term infants at 12 months significantly differentiated between the motion conditions, with the shortest latency observed for forwards optic flow and the longest latency for random visual motion, while preterm infants did not improve their latencies with age, nor were they able to differentiate between the motion conditions at 12 months. Differences in induced activities were also observed where comparisons between TSEs of the motion conditions and a static non-flow pattern showed desynchronised theta-band activity in both full-term and preterm infants, with synchronised alpha-beta band activity observed only in the full-term infants at 12 months. Full-term infants at 12 months with a substantial amount of self-produced locomotor experience and neural maturation coupled with faster oscillating cell assemblies, rely on the perception of structured optic flow to move around efficiently in the environment. The poorer responses in the preterm infants could be related to impairment of the dorsal visual stream specialized in the processing of visual motion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. MRI with and without a high-density EEG cap--what makes the difference?

    PubMed

    Klein, Carina; Hänggi, Jürgen; Luechinger, Roger; Jäncke, Lutz

    2015-02-01

    Besides the benefit of combining electroencephalography (EEG) and magnetic resonance imaging (MRI), much effort has been spent to develop algorithms aimed at successfully cleaning the EEG data from MRI-related gradient and ballistocardiological artifacts. However, there are also studies showing a negative influence of the EEG on MRI data quality. Therefore, in the present study, we focused for the first time on the influence of the EEG on morphometric measurements of T1-weighted MRI data (voxel- and surfaced-based morphometry). Here, we demonstrate a strong influence of the EEG on cortical thickness, surface area, and volume as well as subcortical volumes due to local EEG-related inhomogeneities of the static magnetic (B0) and the gradient field (B1). In a second step, we analyzed the signal-to-noise ratios for both the anatomical and the functional data when recorded simultaneously with EEG and MRI and compared them to the ratios of the MRI data without simultaneous EEG measurements. These analyses revealed consistently lower signal-to-noise ratios for anatomical as well as functional MRI data during simultaneous EEG registration. In contrast, further analyses of T2*-weighted images provided reliable results independent of whether including the individuals' T1-weighted image with or without the EEG cap in the fMRI preprocessing stream. Based on our findings, we strongly recommend against using the structural images obtained during simultaneous EEG-MRI recordings for further anatomical data analysis.

  5. High density wireless EEG prototype: Design and evaluation against reference equipment.

    PubMed

    Rossi, Stefano; Patki, Shrishail; Passoni, Marco; Perko, Hannes; Gritsch, Gerhard; Ossenblok, Pauly; Yazicioglu, Refet Firat

    2014-01-01

    A high density wireless electroencephalographic (EEG) platform has been designed. It is able to record up to 64 EEG channels with electrode to tissue impedance (ETI) monitoring. The analog front-end is based on two kinds of low power ASICs implementing the active electrodes and the amplifier. A power efficient compression algorithm enables the use of continuous wireless transmission of data through Bluetooth for real-time monitoring with an overall power consumption of about 350 mW. EEG acquisitions on five subjects (one healthy subject and four patients suffering from epilepsy) have been recorded in parallel with a reference system commonly used in clinical practice and data of the wireless prototype and reference system have been processed with an automatic tool for seizure detection and localization. The false alarm rates (0.1-0.5 events per hour) are comparable between the two system and wireless prototype also detected the seizure correctly and allowed its localization.

  6. A High-Density EEG Investigation into Steady State Binaural Beat Stimulation

    PubMed Central

    Goodin, Peter; Ciorciari, Joseph; Baker, Kate; Carrey, Anne-Marie; Harper, Michelle; Kaufman, Jordy

    2012-01-01

    Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others. PMID:22496862

  7. A high-density EEG investigation into steady state binaural beat stimulation.

    PubMed

    Goodin, Peter; Ciorciari, Joseph; Baker, Kate; Carey, Anne-Marie; Carrey, Anne-Marie; Harper, Michelle; Kaufman, Jordy

    2012-01-01

    Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others.

  8. Identifying auditory attention with ear-EEG: cEEGrid versus high-density cap-EEG comparison

    NASA Astrophysics Data System (ADS)

    Bleichner, Martin G.; Mirkovic, Bojana; Debener, Stefan

    2016-12-01

    Objective. This study presents a direct comparison of a classical EEG cap setup with a new around-the-ear electrode array (cEEGrid) to gain a better understanding of the potential of ear-centered EEG. Approach. Concurrent EEG was recorded from a classical scalp EEG cap and two cEEGrids that were placed around the left and the right ear. Twenty participants performed a spatial auditory attention task in which three sound streams were presented simultaneously. The sound streams were three seconds long and differed in the direction of origin (front, left, right) and the number of beats (3, 4, 5 respectively), as well as the timbre and pitch. The participants had to attend to either the left or the right sound stream. Main results. We found clear attention modulated ERP effects reflecting the attended sound stream for both electrode setups, which agreed in morphology and effect size. A single-trial template matching classification showed that the direction of attention could be decoded significantly above chance (50%) for at least 16 out of 20 participants for both systems. The comparably high classification results of the single trial analysis underline the quality of the signal recorded with the cEEGrids. Significance. These findings are further evidence for the feasibility of around the-ear EEG recordings and demonstrate that well described ERPs can be measured. We conclude that concealed behind-the-ear EEG recordings can be an alternative to classical cap EEG acquisition for auditory attention monitoring.

  9. Seizure Onset Zone Localization from Ictal High-Density EEG in Refractory Focal Epilepsy.

    PubMed

    Staljanssens, Willeke; Strobbe, Gregor; Holen, Roel Van; Birot, Gwénaël; Gschwind, Markus; Seeck, Margitta; Vandenberghe, Stefaan; Vulliémoz, Serge; van Mierlo, Pieter

    2017-03-01

    Epilepsy surgery is the most efficient treatment option for patients with refractory epilepsy. Before surgery, it is of utmost importance to accurately delineate the seizure onset zone (SOZ). Non-invasive EEG is the most used neuroimaging technique to diagnose epilepsy, but it is hard to localize the SOZ from EEG due to its low spatial resolution and because epilepsy is a network disease, with several brain regions becoming active during a seizure. In this work, we propose and validate an approach based on EEG source imaging (ESI) combined with functional connectivity analysis to overcome these problems. We considered both simulations and real data of patients. Ictal epochs of 204-channel EEG and subsets down to 32 channels were analyzed. ESI was done using realistic head models and LORETA was used as inverse technique. The connectivity pattern between the reconstructed sources was calculated, and the source with the highest number of outgoing connections was selected as SOZ. We compared this algorithm with a more straightforward approach, i.e. selecting the source with the highest power after ESI as the SOZ. We found that functional connectivity analysis estimated the SOZ consistently closer to the simulated EZ/RZ than localization based on maximal power. Performance, however, decreased when 128 electrodes or less were used, especially in the realistic data. The results show the added value of functional connectivity analysis for SOZ localization, when the EEG is obtained with a high-density setup. Next to this, the method can potentially be used as objective tool in clinical settings.

  10. Differences between MEG and high-density EEG source localizations using a distributed source model in comparison to fMRI.

    PubMed

    Klamer, Silke; Elshahabi, Adham; Lerche, Holger; Braun, Christoph; Erb, Michael; Scheffler, Klaus; Focke, Niels K

    2015-01-01

    Electroencephalography (EEG) and magnetoencephalography (MEG) are widely used to localize brain activity and their spatial resolutions have been compared in several publications. While most clinical studies demonstrated higher accuracy of MEG source localization, simulation studies suggested a more accurate EEG than MEG localization for the same number of channels. However, studies comparing real MEG and EEG data with equivalent number of channels are scarce. We investigated 14 right-handed healthy subjects performing a motor task in MEG, high-density-(hd-) EEG and fMRI as well as a somatosensory task in MEG and hd-EEG and compared source analysis results of the evoked brain activity between modalities with different head models. Using individual head models, hd-EEG localized significantly closer to the anatomical reference point obtained by fMRI than MEG. Source analysis results were least accurate for hd-EEG based on a standard head model. Further, hd-EEG and MEG localized more medially than fMRI. Localization accuracy of electric source imaging is dependent on the head model used with more accurate results obtained with individual head models. If this is taken into account, EEG localization can be more accurate than MEG localization for the same number of channels.

  11. IMMUNOLOGIC STUDIES OF HUMAN HIGH DENSITY LIPOPROTEINS

    PubMed Central

    DeLalla, Louis; Levine, Lawrence; Brown, Ray K.

    1957-01-01

    High density serum lipoprotein underwent serologic and physicochemical alterations on aging during storage at 0°C. for 1 month, as judged by decrease of diffusion coefficient and increase of C' fixation. Ultracentrifugation, dialysis, and high concentrations of sodium chloride did not cause these changes. A protein sedimenting at density 1.24 in the ultracentrifuge reacted with antiserum to high density lipoprotein. Probably it was the protein portion of α lipoprotein dissociated from the lipide during ultracentrifugation. Although the antiserum to high density lipoprotein did not react with low density lipoprotein prepared from normal serum, it reacted with similarly prepared lipoproteins from the serum of a patient with biliary cirrhosis. PMID:13449236

  12. Pattern recognition with adaptive-thresholds for sleep spindle in high density EEG signals.

    PubMed

    Gemignani, Jessica; Agrimi, Jacopo; Cheli, Enrico; Gemignani, Angelo; Laurino, Marco; Allegrini, Paolo; Landi, Alberto; Menicucci, Danilo

    2015-01-01

    Medicine and Surgery, University of Pisa, via Savi 10, 56126, Pisa, Italy Sleep spindles are electroencephalographic oscillations peculiar of non-REM sleep, related to neuronal mechanisms underlying sleep restoration and learning consolidation. Based on their very singular morphology, sleep spindles can be visually recognized and detected, even though this approach can lead to significant mis-detections. For this reason, many efforts have been put in developing a reliable algorithm for spindle automatic detection, and a number of methods, based on different techniques, have been tested via visual validation. This work aims at improving current pattern recognition procedures for sleep spindles detection by taking into account their physiological sources of variability. We provide a method as a synthesis of the current state of art that, improving dynamic threshold adaptation, is able to follow modification of spindle characteristics as a function of sleep depth and inter-subjects variability. The algorithm has been applied to physiological data recorded by a high density EEG in order to perform a validation based on visual inspection and on evaluation of expected results from normal night sleep in healthy subjects.

  13. Pattern Recognition With Adaptive-Thresholds For Sleep Spindle In High Density EEG Signals

    PubMed Central

    Gemignani, Jessica; Agrimi, Jacopo; Cheli, Enrico; Gemignani, Angelo; Laurino, Marco; Allegrini, Paolo; Landi, Alberto; Menicucci, Danilo

    2016-01-01

    Sleep spindles are electroencephalographic oscillations peculiar of non-REM sleep, related to neuronal mechanisms underlying sleep restoration and learning consolidation. Based on their very singular morphology, sleep spindles can be visually recognized and detected, even though this approach can lead to significant mis-detections. For this reason, many efforts have been put in developing a reliable algorithm for spindle automatic detection, and a number of methods, based on different techniques, have been tested via visual validation. This work aims at improving current pattern recognition procedures for sleep spindles detection by taking into account their physiological sources of variability. We provide a method as a synthesis of the current state of art that, improving dynamic threshold adaptation, is able to follow modification of spindle characteristics as a function of sleep depth and inter-subjects variability. The algorithm has been applied to physiological data recorded by a high density EEG in order to perform a validation based on visual inspection and on evaluation of expected results from normal night sleep in healthy subjects. PMID:26736332

  14. Antidepressant Effects of Selective Slow Wave Sleep Deprivation in Major Depression: A High-Density EEG Investigation

    PubMed Central

    Landsness, Eric C.; Goldstein, Michael R.; Peterson, Michael J.; Tononi, Giulio; Benca, Ruth M.

    2011-01-01

    Sleep deprivation can acutely reverse depressive symptoms in some patients with major depression. Because abnormalities in slow wave sleep are one of the most consistent biological markers of depression, it is plausible that the antidepressant effects of sleep deprivation are due to the effects on slow wave homeostasis. This study tested the prediction that selectively reducing slow waves during sleep (slow wave deprivation; SWD), without disrupting total sleep time, will lead to an acute reduction in depressive symptomatology. As part of a multi-night, cross-over design study, participants with major depression (non-medicated; n = 17) underwent baseline, SWD, and recovery sleep sessions, and were recorded with high-density EEG (hdEEG). During SWD, acoustic stimuli were played to suppress subsequent slow waves, without waking up the participant. The effects of SWD on depressive symptoms were assessed with both self-rated and researcher-administered scales. Participants experienced a significant decrease in depressive symptoms according to both self-rated (p = .007) and researcher-administered (p = .010) scales, while vigilance was unaffected. The reduction in depressive symptoms correlated with the overnight dissipation of fronto-central slow wave activity (SWA) on baseline sleep, the rebound in right frontal all-night SWA on recovery sleep, and the amount of REM sleep on the SWD night. In addition to highlighting the benefits of hdEEG in detecting regional changes in brain activity, these findings suggest that SWD may help to better understand the pathophysiology of depression and may be a useful tool for the neuromodulatory reversal of depressive symptomatology. PMID:21397252

  15. Effects of oral temazepam on sleep spindles during non-rapid eye movement sleep: a high-density EEG investigation

    PubMed Central

    Plante, DT; Goldstein, MR; Cook, JD; Smith, R; Riedner, BA; Rumble, ME; Jelenchick, L; Roth, A; Tononi, G; Benca, RM; Peterson, MJ

    2015-01-01

    Benzodiazepines are commonly used medications that alter sleep spindles during non-rapid eye movement (NREM) sleep, however the topographic changes to these functionally significant waveforms have yet to be fully elucidated. This study utilized high-density electroencephalography (hdEEG) to investigate topographic changes in sleep spindles and spindle-range activity caused by temazepam during NREM sleep in 18 healthy adults. After an accommodation night, sleep for all participants was recorded on two separate nights after taking either placebo or oral temazepam 15mg. Sleep was monitored using 256-channel hdEEG. Spectral analysis and spindle waveform detection of sleep EEG data were performed for each participant night. Global and topographic data were subsequently compared between temazepam and placebo conditions. Temazepam was associated with significant increases in spectral power from 10.33–13.83Hz. Within this frequency band, temazepam broadly increased sleep spindle duration, and topographically increased spindle amplitude and density in frontal and central-posterior regions, respectively. Higher frequency sleep spindles demonstrated increased spindle amplitude and a paradoxical decrease in spindle density in frontal and centroparietal regions. Further analysis demonstrated temazepam both slowed the average frequency of spindle waveforms and increased the relative proportion of spindles at peak frequencies in frontal and centroparietal regions. These findings suggest that benzodiazepines have diverse effects on sleep spindles that vary by frequency and cortical topography. Further research that explores the relationships between topographic and frequency-dependent changes in pharmacologically-induced sleep spindles and the functional effects of these waveforms is indicated. PMID:26195197

  16. Combining Computer Game-Based Behavioural Experiments With High-Density EEG and Infrared Gaze Tracking

    PubMed Central

    Yoder, Keith J.; Belmonte, Matthew K.

    2010-01-01

    Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they yield data relevant to the cognitive processing that occurs under ecologically valid conditions. These two goals often are at odds, since well controlled stimuli often are too repetitive to sustain subjects' motivation. Studies employing electroencephalography (EEG) are often especially sensitive to this dilemma between ecological validity and experimental control: attaining sufficient signal-to-noise in physiological averages demands large numbers of repeated trials within lengthy recording sessions, limiting the subject pool to individuals with the ability and patience to perform a set task over and over again. This constraint severely limits researchers' ability to investigate younger populations as well as clinical populations associated with heightened anxiety or attentional abnormalities. Even adult, non-clinical subjects may not be able to achieve their typical levels of performance or cognitive engagement: an unmotivated subject for whom an experimental task is little more than a chore is not the same, behaviourally, cognitively, or neurally, as a subject who is intrinsically motivated and engaged with the task. A growing body of literature demonstrates that embedding experiments within video games may provide a way between the horns of this dilemma between experimental control and ecological validity. The narrative of a game provides a more realistic context in which tasks occur, enhancing their ecological validity (Chaytor & Schmitter-Edgecombe, 2003). Moreover, this context provides motivation to complete tasks. In our game, subjects perform various missions to collect resources, fend off pirates, intercept communications or facilitate diplomatic relations. In so doing, they also perform an array of cognitive tasks, including a Posner attention-shifting paradigm (Posner, 1980), a go/no-go test of motor

  17. Combining computer game-based behavioural experiments with high-density EEG and infrared gaze tracking.

    PubMed

    Yoder, Keith J; Belmonte, Matthew K

    2010-12-16

    Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they yield data relevant to the cognitive processing that occurs under ecologically valid conditions. These two goals often are at odds, since well controlled stimuli often are too repetitive to sustain subjects' motivation. Studies employing electroencephalography (EEG) are often especially sensitive to this dilemma between ecological validity and experimental control: attaining sufficient signal-to-noise in physiological averages demands large numbers of repeated trials within lengthy recording sessions, limiting the subject pool to individuals with the ability and patience to perform a set task over and over again. This constraint severely limits researchers' ability to investigate younger populations as well as clinical populations associated with heightened anxiety or attentional abnormalities. Even adult, non-clinical subjects may not be able to achieve their typical levels of performance or cognitive engagement: an unmotivated subject for whom an experimental task is little more than a chore is not the same, behaviourally, cognitively, or neurally, as a subject who is intrinsically motivated and engaged with the task. A growing body of literature demonstrates that embedding experiments within video games may provide a way between the horns of this dilemma between experimental control and ecological validity. The narrative of a game provides a more realistic context in which tasks occur, enhancing their ecological validity (Chaytor & Schmitter-Edgecombe, 2003). Moreover, this context provides motivation to complete tasks. In our game, subjects perform various missions to collect resources, fend off pirates, intercept communications or facilitate diplomatic relations. In so doing, they also perform an array of cognitive tasks, including a Posner attention-shifting paradigm (Posner, 1980), a go/no-go test of motor

  18. Functional brain network organisation of children between 2 and 5 years derived from reconstructed activity of cortical sources of high-density EEG recordings.

    PubMed

    Bathelt, Joe; O'Reilly, Helen; Clayden, Jonathan D; Cross, J Helen; de Haan, Michelle

    2013-11-15

    There is increasing interest in applying connectivity analysis to brain measures (Rubinov and Sporns, 2010), but most studies have relied on fMRI, which substantially limits the participant groups and numbers that can be studied. High-density EEG recordings offer a comparatively inexpensive easy-to-use alternative, but require channel-level connectivity analysis which currently lacks a common analytic framework and is very limited in spatial resolution. To address this problem, we have developed a new technique for studies of network development that overcomes the spatial constraint and obtains functional networks of cortical areas by using EEG source reconstruction with age-matched average MRI templates (He et al., 1999). In contrast to previously reported channel-level analysis, this approach provides information about the cortical areas most likely to be involved in the network as well as their functional relationship (Babiloni et al., 2005; De Vico Fallani et al., 2007). In this study, we applied source reconstruction with age-matched templates to task-free high-density EEG recordings in typically-developing children between 2 and 6 years of age (O'Reilly, 2012). Graph theory was then applied to the association strengths of 68 cortical regions of interest based on the Desikan-Killiany atlas. We found linear increases of mean node degree, mean clustering coefficient and maximum betweenness centrality between 2 years and 6 years of age. Characteristic path length was negatively correlated with age. The correlation of the network measures with age indicates network development towards more closely integrated networks similar to reports from other imaging modalities (Fair et al., 2008; Power et al., 2010). We also applied eigenvalue decomposition to obtain functional modules (Clayden et al., 2013). Connection strength within these modules did not change with age, and the modules resembled hub networks previously described for MRI (Hagmann et al., 2010; Power et al

  19. Different colors of light lead to different adaptation and activation as determined by high-density EEG.

    PubMed

    Münch, M; Plomp, G; Thunell, E; Kawasaki, A; Scartezzini, J L; Herzog, M H

    2014-11-01

    Light adaptation is crucial for coping with the varying levels of ambient light. Using high-density electroencephalography (EEG), we investigated how adaptation to light of different colors affects brain responsiveness. In a within-subject design, sixteen young participants were adapted first to dim white light and then to blue, green, red, or white bright light (one color per session in a randomized order). Immediately after both dim and bright light adaptation, we presented brief light pulses and recorded event-related potentials (ERPs). We analyzed ERP response strengths and brain topographies and determined the underlying sources using electrical source imaging. Between 150 and 261 ms after stimulus onset, the global field power (GFP) was higher after dim than bright light adaptation. This effect was most pronounced with red light and localized in the frontal lobe, the fusiform gyrus, the occipital lobe and the cerebellum. After bright light adaptation, within the first 100 ms after light onset, stronger responses were found than after dim light adaptation for all colors except for red light. Differences between conditions were localized in the frontal lobe, the cingulate gyrus, and the cerebellum. These results indicate that very short-term EEG brain responses are influenced by prior light adaptation and the spectral quality of the light stimulus. We show that the early EEG responses are differently affected by adaptation to different colors of light which may contribute to known differences in performance and reaction times in cognitive tests.

  20. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: a high density EEG investigation

    PubMed Central

    Plante, David T.; Goldstein, Michael R.; Cook, Jesse D.; Smith, Richard; Riedner, Brady A.; Rumble, Meredith E.; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M.; Peterson, Michael J.

    2015-01-01

    Objective Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Methods Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Results Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Conclusions Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. Significance These results demonstrate a homeostatic response to partial sleep loss in humans. PMID:26596212

  1. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: A high density EEG investigation.

    PubMed

    Plante, David T; Goldstein, Michael R; Cook, Jesse D; Smith, Richard; Riedner, Brady A; Rumble, Meredith E; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M; Peterson, Michael J

    2016-02-01

    Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. These results demonstrate a homeostatic response to partial sleep loss in humans. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  2. Concordance of Epileptic Networks Associated with Epileptic Spikes Measured by High-Density EEG and Fast fMRI

    PubMed Central

    Jäger, Vera; Dümpelmann, Matthias; LeVan, Pierre; Ramantani, Georgia; Mader, Irina; Schulze-Bonhage, Andreas; Jacobs, Julia

    2015-01-01

    Objective The present study aims to investigate whether a newly developed fast fMRI called MREG (magnetic resonance encephalography) measures metabolic changes related to interictal epileptic discharges (IED). For this purpose BOLD changes are correlated with the IED distribution and variability. Methods Patients with focal epilepsy underwent EEG-MREG using a 64 channel cap. IED voltage maps were generated using 32 and 64 channels and compared regarding their correspondence to the BOLD response. The extents of IEDs (defined as number of channels with >50% of maximum IED negativity) were correlated with the extents of positive and negative BOLD responses. Differences in inter-spike variability were investigated between interictal epileptic discharges (IED) sets with and without concordant positive or negative BOLD responses. Results 17 patients showed 32 separate IED types. In 50% of IED types the BOLD changes could be confirmed by another independent imaging method. The IED extent significantly correlated with the positive BOLD extent (p = 0.04). In 6 patients the 64-channel EEG voltage maps better reflected the positive or negative BOLD response than the 32-channel EEG; in all others no difference was seen. Inter-spike variability was significantly lower in IED sets with than without concordant positive or negative BOLD responses (with p = 0.04). Significance Higher density EEG and fast fMRI seem to improve the value of EEG-fMRI in epilepsy. The correlation of positive BOLD and IED extent could suggest that widespread BOLD responses reflect the IED network. Inter-spike variability influences the likelihood to find IED concordant positive or negative BOLD responses, which is why single IED analysis may be promising. PMID:26496480

  3. Power spectral density changes and language lateralization during covert object naming tasks measured with high-density EEG recordings.

    PubMed

    Ramon, C; Holmes, M; Freeman, Walter J; Gratkowski, Maciej; Eriksen, K J; Haueisen, Jens

    2009-01-01

    Our objective was to study changes in EEG time-domain power spectral density (PSDt) and localization of language areas during covert object naming tasks in human subjects with epilepsy. EEG data for subjects with epilepsy were acquired during the covert object naming tasks using a net of 256 electrodes. The trials required each subject to provide the names of common objects presented every 4 seconds on slides. Each trial comprised the 1.0 second before and 3.0 seconds after initial object presentation. PSDt values at baseline and during tasks were calculated in the theta, alpha, beta, low gamma, and high gamma bands. The spatial contour plots reveal that PSDt values during object naming were 10-20% higher than the baseline values for different bands. Language was lateralized to left frontal or temporal areas. In all cases, the Wada test disclosed language lateralization to the left hemisphere as well.

  4. An exploratory high-density EEG investigation of the misinformation effect: Attentional and recollective differences between true and false perceptual memories.

    PubMed

    Kiat, John E; Belli, Robert F

    2017-05-01

    The misinformation effect, a phenomenon in which eyewitness memories are altered via exposure to post-event misinformation, is one of the most important paradigms used to investigate the reconstructive nature of human memory. The aim of this study was to use the misinformation effect paradigm to investigate differences in attentional and recollective processing between true and false event memories. Nineteen participants completed a variant of the misinformation paradigm in which recognition responses to true and misinformation based event details embedded within a narrative context, were investigated using high-density (256-channel) EEG with a 1-day delay between event exposure and test. Source monitoring responses were used to isolate event-related-potentials (ERPs) associated with perceptual (i.e. event) source attributions. Temporal-spatial analyses of these ERPs showed evidence of an elevated P3b and Late-Positive Component, associated with stronger context-matching responses and recollective activity respectively, in true perceptual memories relative to false misinformation based ones. These findings represent the first retrieval focused EEG investigation of the misinformation effect and highlight the interplay between attention and retrieval processes in episodic memory recognition. Published by Elsevier Inc.

  5. EEG Studies with Young Children.

    ERIC Educational Resources Information Center

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

    2000-01-01

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

  6. EEG Studies with Young Children.

    ERIC Educational Resources Information Center

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

    2000-01-01

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

  7. Patterned Platinum Etching Studies in an Argon High Density Plasma

    NASA Astrophysics Data System (ADS)

    Delprat, Sébastien; Chaker, Mohamed; Margot, Joëlle; Pépin, Henri; Tan, Liang; Smy, Tom

    1998-10-01

    A high-density surface-wave Ar plasma operated in the low pressure regime is used to study pure physical etching characteristics of platinum thin films. The platinum samples are RF biased so as to obtain a maximum DC self-bias voltage of 150 V. The sputter-etching characteristics are investigated as a function of the magnetic field intensity, the self-bias voltage and the gas pressure. At 1 mtorr, the etch rate is found to be a unique linear function of both the self-bias voltage and the ion density, independently of the magnetic field intensity value. However, even though the ion density increases, the etch rate is found to decrease with increasing pressure. In the low pressure regime, etch rates as high as 2000 A/min are obtained with a good selectivity over resist. Without any optimization of the etching process, we were able to etch 0.5 micron Pt trenches, 0.6 micron thick yielding fence-free profiles and sidewall angles (75º) that already meets the present industrial requirements of NVRAM technology.

  8. Effects of oral temazepam on slow waves during non-rapid eye movement sleep in healthy young adults: a high-density EEG investigation

    PubMed Central

    Plante, DT; Goldstein, MR; Cook, JD; Smith, R; Riedner, BA; Rumble, ME; Jelenchick, L; Roth, A; Tononi, G; Benca, RM; Peterson, MJ

    2016-01-01

    Slow waves are characteristic waveforms that occur during non-rapid eye movement (NREM) sleep that play an integral role in sleep quality and brain plasticity. Benzodiazepines are commonly used medications that alter slow waves, however, their effects may depend on the time of night and measure used to characterize slow waves. Prior investigations have utilized minimal scalp derivations to evaluate the effects of benzodiazepines on slow waves, and thus the topography of changes to slow waves induced by benzodiazepines has yet to be fully elucidated. This study used high-density electroencephalography (hdEEG) to evaluate the effects of oral temazepam on slow wave activity, incidence, and morphology during NREM sleep in 18 healthy adults relative to placebo. Temazepam was associated with significant decreases in slow wave activity and incidence, which were most prominent in the latter portions of the sleep period. However, temazepam was also associated with a decrease in the magnitude of high-amplitude slow waves and their slopes in the first NREM sleep episode, which was most prominent in frontal derivations. These findings suggest that benzodiazepines produce changes in slow waves throughout the night that vary depending on cortical topography and measures used to characterize slow waves. Further research that explores the relationships between benzodiazepine-induced changes to slow waves and the functional effects of these waveforms is indicated. PMID:26779596

  9. Effects of oral temazepam on slow waves during non-rapid eye movement sleep in healthy young adults: A high-density EEG investigation.

    PubMed

    Plante, D T; Goldstein, M R; Cook, J D; Smith, R; Riedner, B A; Rumble, M E; Jelenchick, L; Roth, A; Tononi, G; Benca, R M; Peterson, M J

    2016-03-01

    Slow waves are characteristic waveforms that occur during non-rapid eye movement (NREM) sleep that play an integral role in sleep quality and brain plasticity. Benzodiazepines are commonly used medications that alter slow waves, however, their effects may depend on the time of night and measure used to characterize slow waves. Prior investigations have utilized minimal scalp derivations to evaluate the effects of benzodiazepines on slow waves, and thus the topography of changes to slow waves induced by benzodiazepines has yet to be fully elucidated. This study used high-density electroencephalography (hdEEG) to evaluate the effects of oral temazepam on slow wave activity, incidence, and morphology during NREM sleep in 18 healthy adults relative to placebo. Temazepam was associated with significant decreases in slow wave activity and incidence, which were most prominent in the latter portions of the sleep period. However, temazepam was also associated with a decrease in the magnitude of high-amplitude slow waves and their slopes in the first NREM sleep episode, which was most prominent in frontal derivations. These findings suggest that benzodiazepines produce changes in slow waves throughout the night that vary depending on cortical topography and measures used to characterize slow waves. Further research that explores the relationships between benzodiazepine-induced changes to slow waves and the functional effects of these waveforms is indicated.

  10. Algorithm to find high density EEG scalp coordinates and analysis of their correspondence to structural and functional regions of the brain.

    PubMed

    Giacometti, Paolo; Perdue, Katherine L; Diamond, Solomon G

    2014-05-30

    Interpretation and analysis of electroencephalography (EEG) measurements relies on the correspondence of electrode scalp coordinates to structural and functional regions of the brain. An algorithm is introduced for automatic calculation of the International 10-20, 10-10, and 10-5 scalp coordinates of EEG electrodes on a boundary element mesh of a human head. The EEG electrode positions are then used to generate parcellation regions of the cerebral cortex based on proximity to the EEG electrodes. The scalp electrode calculation method presented in this study effectively and efficiently identifies EEG locations without prior digitization of coordinates. The average of electrode proximity parcellations of the cortex were tabulated with respect to structural and functional regions of the brain in a population of 20 adult subjects. Parcellations based on electrode proximity and EEG sensitivity were compared. The parcellation regions based on sensitivity and proximity were found to have 44.0 ± 11.3% agreement when demarcated by the International 10-20, 32.4 ± 12.6% by the 10-10, and 24.7 ± 16.3% by the 10-5 electrode positioning system. The EEG positioning algorithm is a fast and easy method of locating EEG scalp coordinates without the need for digitized electrode positions. The parcellation method presented summarizes the EEG scalp locations with respect to brain regions without computation of a full EEG forward model solution. The reference table of electrode proximity versus cortical regions may be used by experimenters to select electrodes that correspond to anatomical and functional regions of interest. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Algorithm to find high density EEG scalp coordinates and analysis of their correspondence to structural and functional regions of the brain

    PubMed Central

    Giacometti, Paolo; Perdue, Katherine L.; Diamond, Solomon G.

    2014-01-01

    Background Interpretation and analysis of electroencephalography (EEG) measurements relies on the correspondence of electrode scalp coordinates to structural and functional regions of the brain. New Method An algorithm is introduced for automatic calculation of the International 10–20, 10-10, and 10-5 scalp coordinates of EEG electrodes on a boundary element mesh of a human head. The EEG electrode positions are then used to generate parcellation regions of the cerebral cortex based on proximity to the EEG electrodes. Results The scalp electrode calculation method presented in this study effectively and efficiently identifies EEG locations without prior digitization of coordinates. The average of electrode proximity parcellations of the cortex were tabulated with respect to structural and functional regions of the brain in a population of 20 adult subjects. Comparison with Existing Methods Parcellations based on electrode proximity and EEG sensitivity were compared. The parcellation regions based on sensitivity and proximity were found to have 44.0 ± 11.3% agreement when demarcated by the International 10–20, 32.4 ± 12.6% by the 10-10, and 24.7 ± 16.3% by the 10-5 electrode positioning system. Conclusions The EEG positioning algorithm is a fast and easy method of locating EEG scalp coordinates without the need for digitized electrode positions. The parcellation method presented summarizes the EEG scalp locations with respect to brain regions without computation of a full EEG forward model solution. The reference table of electrode proximity versus cortical regions may be used by experimenters to select electrodes that correspond to anatomical and functional regions of interest. PMID:24769168

  12. Experimental study of high density foods for the Space Operations Center

    NASA Technical Reports Server (NTRS)

    Ahmed, S. M.

    1981-01-01

    The experimental study of high density foods for the Space Operations Center is described. A sensory evaluation of the high density foods was conducted first to test the acceptability of the products. A shelf-life study of the high density foods was also conducted for three different time lengths at three different temperatures. The nutritional analysis of the high density foods is at present incomplete.

  13. Experimental study of high density foods for the Space Operations Center

    NASA Technical Reports Server (NTRS)

    Ahmed, S. M.

    1981-01-01

    The experimental study of high density foods for the Space Operations Center is described. A sensory evaluation of the high density foods was conducted first to test the acceptability of the products. A shelf-life study of the high density foods was also conducted for three different time lengths at three different temperatures. The nutritional analysis of the high density foods is at present incomplete.

  14. Mapping of cortical activity in the first two decades of life: a high-density sleep electroencephalogram study.

    PubMed

    Kurth, Salomé; Ringli, Maya; Geiger, Anja; LeBourgeois, Monique; Jenni, Oskar G; Huber, Reto

    2010-10-06

    Evidence that electroencephalography (EEG) slow-wave activity (SWA) (EEG spectral power in the 1-4.5 Hz band) during non-rapid eye movement sleep (NREM) reflects plastic changes is increasing (Tononi and Cirelli, 2006). Regional assessment of gray matter development from neuroimaging studies reveals a posteroanterior trajectory of cortical maturation in the first three decades of life (Shaw et al., 2008). Our aim was to test whether this regional cortical maturation is reflected in regional changes of sleep SWA. We evaluated all-night high-density EEG (128 channels) in 55 healthy human subjects (2.4-19.4 years) and assessed age-related changes in NREM sleep topography. As in adults, we observed frequency-specific topographical distributions of sleep EEG power in all subjects. However, from early childhood to late adolescence, the location on the scalp showing maximal SWA underwent a shift from posterior to anterior regions. This shift along the posteroanterior axis was only present in the SWA frequency range and remained stable across the night. Changes in the topography of SWA during sleep parallel neuroimaging study findings indicating cortical maturation starts early in posterior areas and spreads rostrally over the frontal cortex. Thus, SWA might reflect the underlying processes of cortical maturation. In the future, sleep SWA assessments may be used as a clinical tool to detect aberrations in cortical maturation.

  15. Scoping study. High density polyethylene (HDPE) in salstone service

    SciTech Connect

    Phifer, Mark A.

    2005-02-18

    An evaluation of the use of high density polyethylene (HDPE) geomembranes in Saltstone service has been conducted due to the potential benefits that could be derived from such usage. HDPE is one of the simplest hydrocarbon polymers and one of the most common polymers utilized in the production of geomembranes, which means that its costs are relatively low. Additionally, HDPE geomembranes have an extremely low permeability and an extremely low water vapor diffusional flux, which means that it is a good barrier to contaminant transport. The primary consideration in association with HDPE geomembranes in Saltstone service is the potential impact of Saltstone on the degradation of the HDPE geomembranes. Therefore, the evaluation documented herein has primarily focused upon the potential HDPE degradation in Saltstone service.

  16. Fundamental Study of Interactions Between Pulsed High-Density Plasmas and Materials for Space Propulsion

    DTIC Science & Technology

    2016-05-23

    AFRL-AFOSR-VA-TR-2016-0199 FUNDAMENTAL STUDY OF INTERACTIONS BETWEEN PULSED HIGH-DENSITY PLASMAS AND MATERIALS FOR SPACE PROPULSION LAXAMIRIAN RAJA...CONTRACT NUMBER FA9550-11-1-0062 FUNDAMENTAL STUDY OF INTERACTIONS BETWEEN PULSED HIGH-DENSITY LASMAS AND MATERIALS FOR SPACE PROPULSION 5b. GRANT... SPACE PROPULSION Principal Investigators: L. L. Raja, I. McNab, F. Stefani, R. D. Bengtson, G. Henkelman, F. Stefani The University of Texas at

  17. A Review of Issues Related to Data Acquisition and Analysis in EEG/MEG Studies

    PubMed Central

    Puce, Aina; Hämäläinen, Matti S.

    2017-01-01

    Electroencephalography (EEG) and magnetoencephalography (MEG) are non-invasive electrophysiological methods, which record electric potentials and magnetic fields due to electric currents in synchronously-active neurons. With MEG being more sensitive to neural activity from tangential currents and EEG being able to detect both radial and tangential sources, the two methods are complementary. Over the years, neurophysiological studies have changed considerably: high-density recordings are becoming de rigueur; there is interest in both spontaneous and evoked activity; and sophisticated artifact detection and removal methods are available. Improved head models for source estimation have also increased the precision of the current estimates, particularly for EEG and combined EEG/MEG. Because of their complementarity, more investigators are beginning to perform simultaneous EEG/MEG studies to gain more complete information about neural activity. Given the increase in methodological complexity in EEG/MEG, it is important to gather data that are of high quality and that are as artifact free as possible. Here, we discuss some issues in data acquisition and analysis of EEG and MEG data. Practical considerations for different types of EEG and MEG studies are also discussed. PMID:28561761

  18. The Mozart Effect: A quantitative EEG study.

    PubMed

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

    2015-09-01

    The aim of this study is to investigate the influence of Mozart's music on brain activity through spectral analysis of the EEG in young healthy adults (Adults), in healthy elderly (Elderly) and in elderly with Mild Cognitive Impairment (MCI). EEG recording was performed at basal rest conditions and after listening to Mozart's K448 or "Fur Elise" Beethoven's sonatas. After listening to Mozart, an increase of alpha band and median frequency index of background alpha rhythm activity (a pattern of brain wave activity linked to memory, cognition and open mind to problem solving) was observed both in Adults and in Elderly. No changes were observed in MCI. After listening to Beethoven, no changes in EEG activity were detected. This results may be representative of the fact that said Mozart's music is able to "activate" neuronal cortical circuits related to attentive and cognitive functions. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Illumination influences working memory: an EEG study.

    PubMed

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

    2013-09-05

    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.

  20. Relation of black race between high density lipoprotein cholesterol content, high density lipoprotein particles and coronary events (from the Dallas Heart Study).

    PubMed

    Chandra, Alvin; Neeland, Ian J; Das, Sandeep R; Khera, Amit; Turer, Aslan T; Ayers, Colby R; McGuire, Darren K; Rohatgi, Anand

    2015-04-01

    Therapies targeting high-density lipoprotein cholesterol content (HDL-C) have not improved coronary heart disease (CHD) outcomes. High-density lipoprotein particle concentration (HDL-P) may better predict CHD. However, the impact of race/ethnicity on the relations between HDL-P and subclinical atherosclerosis and incident CHD events has not been described. Participants from the Dallas Heart Study (DHS), a multiethnic, probability-based, population cohort of Dallas County adults, underwent the following baseline measurements: HDL-C, HDL-P by nuclear magnetic resonance imaging, and coronary artery calcium by electron-beam computed tomography. Participants were followed for a median of 9.3 years for incident CHD events (composite of first myocardial infarction, stroke, coronary revascularization, or cardiovascular death). The study comprised 1,977 participants free of CHD (51% women, 46% black). In adjusted models, HDL-C was not associated with prevalent coronary artery calcium (p = 0.13) or incident CHD overall (hazard ratio [HR] per 1 SD 0.89, 95% confidence interval [CI] 0.76 to 1.05). However, HDL-C was inversely associated with incident CHD among nonblack (adjusted HR per 1 SD 0.67, 95% CI 0.46 to 0.97) but not black participants (HR 0.94, 95% CI 0.78 to 1.13, pinteraction = 0.05). Conversely, HDL-P, adjusted for risk factors and HDL-C, was inversely associated with prevalent coronary artery calcium (p = 0.009) and with incident CHD overall (adjusted HR per 1 SD 0.73, 95% CI 0.62 to 0.86), with no interaction by black race/ethnicity (pinteraction = 0.57). In conclusion, in contrast to HDL-C, the inverse relation between HDL-P and incident CHD events is consistent across ethnicities. These findings suggest that HDL-P is superior to HDL-C in predicting prevalent atherosclerosis as well as incident CHD events across a diverse population and should be considered as a therapeutic target. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Crystallization Studies of Blends of Low Density Polyethylene and High Density Polyethylene

    NASA Astrophysics Data System (ADS)

    Puig, C.; Gomez, S.; Castañeda, R.

    1997-03-01

    The incorporation of low density polyethylene (LDPE) segments within the high density polyethylene (HDPE) lamellae on cooling from the molten state is investigated using differential scanning calorimetry. Rich LDPE blends (>80%) on quenching from the melt exhibited partial cocrystallization. Two endotherms on heating are observed, the LDPE is the main component of the low melting endotherm whereas the HDPE is the main component of the high melting endotherm. A depression in the high melting temperature peak is observed. In addition, on subsequent treatment the crystallization behaviour under controlled conditions of the low melting component in quenched blends is studied and it shows a shift in the crystallization temperature when compared with pure LDPE. After reheating a depression in the low melting temperature with increasing HDPE content in the blend is observed. The effect of cooling conditions used from the melt on the cocrystallization between the two polymers is studied.

  2. Study of the photo-detection efficiency of FBK High-Density silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Zappalà, G.; Acerbi, F.; Ferri, A.; Gola, A.; Paternoster, G.; Regazzoni, V.; Zorzi, N.; Piemonte, C.

    2016-11-01

    This work presents a study of the factors contributing to the Photo-Detection Efficiency of Silicon Photomultipliers (SiPMs): Quantum Efficiency, Triggering Probability and Fill Factor. Two different SiPM High-Density technologies are tested, NUV-HD, based on n-on-p junction, and RGB-HD, based on p-on-n junction, developed at FBK, Trento. The quantum efficiency was measured on photodiodes produced along with the SiPMs. The triggering probability, as a function of wavelength and bias voltage, was measured on circular Single Photon Avalanche Diodes (SPADs) with 100% fill factor. Square SPADs, having the same layout of single SiPM cells, were studied to measure the effective fill factor and compare it to the nominal value. The comparison of the circular and square SPADs allows to get the transition region size between the effective active area of the cell and the one defined by the layout.

  3. Density functional study of the electric double layer formed by a high density electrolyte.

    PubMed

    Henderson, Douglas; Lamperski, Stanisław; Jin, Zhehui; Wu, Jianzhong

    2011-11-10

    We use a classical density functional theory (DFT) to study the electric double layer formed by charged hard spheres near a planar charged surface. The DFT predictions are found to be in good agreement with recent computer simulation results. We study the capacitance of the charged hard-sphere system at a range of densities and surface charges and find that the capacitance exhibits a local minimum at low ionic densities and small electrode charge. Although this charging behavior is typical for an aqueous electrolyte solution, the local minimum gradually turns into a maximum as the density of the hard spheres increases. Charged hard spheres at high density provide a reasonable first approximation for ionic liquids. In agreement with experiment, the capacitance of this model ionic liquid double layer has a maximum at small electrode charge density.

  4. Study of short haul high-density V/STOL transportation systems, volume 1

    NASA Technical Reports Server (NTRS)

    Solomon, H. L.

    1972-01-01

    The relative advantages of STOL aircraft concepts were examined by simulating the operations of a short haul high-density intercity STOL system set in two arenas, the California corridor and the Chicago-Detroit-Cleveland triangle, during the 1980 time period. The study was constrained to the use of three aircraft concepts designated as the deflected slipstream turboprop, externally blown flap, and augmentor wing turbofan configurations. The projected demographic, economic, travel demand, and travel characteristics of the representative arenas were identified. The STOL airline operating scenarios were then formulated and through the use of the aerospace modal split simulation program, the traveler modal choices involving alternative STOL concepts were estimated in the context of the total transportation environment for 1980. System combinations that presented the best potential for economic return and traveler acceptance were then identified for each STOL concept.

  5. A pilot study of high-density electromyographic maps of muscle activity in normal deglutition.

    PubMed

    Yu, Bin; Zhu, Mingxing; Xu, Lisheng; Li, Guanglin

    2013-01-01

    While various methods have been used to study physiological aspects of swallowing, few studies have been conducted to investigate the dynamics of a swallowing procedure with the activation pattern of swallowing muscles. In this pilot study we investigated the feasibility of surface electromyographic (sEMG) dynamic topography as a new approach for continuously visualizing muscle activity of normal swallowing. The dynamic sEMG topographies (or potential mappings) of swallowing were constructed with high-density sEMG recordings from three subjects without any swallowing disorders. The root mean square (RMS) of the sEMG signals was calculated as a function of both position and time to produce two-dimension dynamic sEMG maps of the muscle activity during swallowing. The sEMG maps could provide the information about the dynamic characteristics of swallowing muscles, which is accordance with physiological and biomechanical laws of a normal swallowing. With the results of the present study, we might conclude that the dynamic topography would provide a noninvasive means to continuously visualize the distribution of surface EMG signals of complex muscle activities of normal deglutition.

  6. Relation of Black Race between High Density Lipoprotein Cholesterol Content, High Density Lipoprotein Particles and Coronary Events (From the Dallas Heart Study)

    PubMed Central

    Chandra, Alvin; Neeland, Ian J.; Das, Sandeep R.; Khera, Amit; Turer, Aslan T.; Ayers, Colby R.; McGuire, Darren K.; Rohatgi, Anand

    2015-01-01

    Therapies targeting high density lipoprotein cholesterol content (HDL-C) have not improved coronary heart disease (CHD) outcomes. HDL particle concentration (HDL-P) may better predict CHD. However, the impact of race/ethnicity on the relations between HDL-P and subclinical atherosclerosis/ incident CHD events has not been described. Participants from the Dallas Heart Study, a multiethnic, probability-based, population cohort of Dallas County adults had the following baseline measurements: HDL-C, HDL-P by nuclear magnetic resonance imaging (NMR), and coronary artery calcium (CAC) by electron beam computed tomography. Participants were followed for a median of 9.3 years for incident CHD events (composite of first myocardial infarction, stroke, coronary revascularization, or cardiovascular death). The study comprised 1977 participants free from CHD (51% women, 46% Black). In adjusted models, HDL-C was not associated with prevalent CAC (p=0.13) or incident CHD overall (HR per 1SD: 0.89, 95% CI 0.76–1.05). However, HDL-C was inversely associated with incident CHD among non-Black (adjusted HR per 1SD 0.67, 95% CI 0.46–0.97) but not Black participants (HR 0.94, 95% CI 0.78–1.13, pinteraction = 0.05). Conversely, HDL-P, adjusted for risk factors and HDL-C, was inversely associated with prevalent CAC (p=0.009) and with incident CHD overall (adjusted HR per 1SD: 0.73, 95% CI 0.62–0.86) with no interaction by Black race/ethnicity (pinteraction = 0.57). In conclusion, in contrast to HDL-C, the inverse relationship between HDL-P and incident CHD events is consistent across ethnicities. These findings suggest that HDL-P is superior to HDL-C in predicting both prevalent atherosclerosis as well as incident CHD events across a diverse population and should be considered as a therapeutic target. PMID:25661572

  7. Spatiotemporal neural dynamics of moral judgment: a high-density ERP study.

    PubMed

    Yoder, Keith J; Decety, Jean

    2014-07-01

    Morality is a pervasive aspect of human nature across all cultures, and neuroscience investigations are necessary for identifying what computational mechanisms underpin moral cognition. The current study used high-density ERPs to examine how moral evaluations are mediated by automatic and controlled processes as well as how quickly information and causal-intentional representations can be extracted when viewing morally laden behavior. The study also explored the extent to which individual dispositions in affective and cognitive empathy as well as justice sensitivity influence the encoding of moral valence when healthy participants make moral judgments about prosocial (interpersonal assistance) and antisocial (interpersonal harm) actions. Moral judgment differences were reflected in differential amplitudes for components associated with cognitive appraisal (LPP) as well as early components associated with emotional salience (N1 and N2). Moreover, source estimation was performed to indicate potential neural generators. A posterior-to-anterior shift was observed, with current density peaks first in right inferior parietal cortex (at the temporoparietal junction), then later in medial prefrontal cortex. Cognitive empathy scores predicted behavioral ratings of blame as well as differential amplitudes in LPP and component activity at posterior sites. Overall, this study offers important insights into the temporal unfolding of moral evaluations, including when in time individual differences in empathy influence neural encoding of moral valence.

  8. Spatiotemporal neural dynamics of moral judgment: A high-density ERP study

    PubMed Central

    Yoder, Keith J.

    2014-01-01

    Morality is a pervasive aspect of human nature across all cultures, and neuroscience investigations are necessary for identifying what computational mechanisms underpin moral cognition. The current study used high-density ERPs to examine how moral evaluations are mediated by automatic and controlled processes as well as how quickly information and causal-intentional representations can be extracted when viewing morally laden behavior. The study also explored the extent to which individual dispositions in affective and cognitive empathy as well as justice sensitivity influence the encoding of moral valence when healthy participants make moral judgments about prosocial (interpersonal assistance) and antisocial (interpersonal harm) actions. Moral judgment differences were reflected in differential amplitudes for components associated with cognitive appraisal (LPP) as well as early components associated with emotional salience (N1 and N2). Moreover, source estimation was performed to indicate potential neural generators. A posterior-to-anterior shift was observed, with current density peaks first in right inferior parietal cortex (at the temporoparietal junction), then later in medial prefrontal cortex. Cognitive empathy scores predicted behavioral ratings of blame as well as differential amplitudes in LPP and component activity at posterior sites. Overall, this study offers important insights into the temporal unfolding of moral evaluations, including when in time individual differences in empathy influence neural encoding of moral valence. PMID:24905282

  9. High-density lipoprotein cholesterol, obesity, and mammographic density in Korean women: the Healthy Twin study.

    PubMed

    Sung, Joohon; Song, Yun-Mi; Stone, Jennifer; Lee, Kayoung; Kim, Sun-Young

    2011-01-01

    High-density lipoprotein cholesterol (HDL-C) is reported to be associated with breast cancer risk. To better understand this association, we examined the relationship between HDL-C and mammographic density, a putative intermediate risk factor for breast cancer. The study subjects were 711 Korean women from the Healthy Twin study. Lipid parameters were assayed enzymatically in fresh sera, and percent dense area (PDA) and absolute dense area were measured from digital mammograms using a computer-assisted method. PDA was positively associated with HDL-C in both premenopausal and postmenopausal women in a multivariable-adjusted linear mixed model, but the association did not persist when the model was additionally adjusted for body mass index (BMI). BMI was inversely associated with PDA, and this association did not change after additional adjustment for any lipid parameter. Multivariable-adjusted analysis showed that there were significant additive genetic cross-trait correlations between PDA and both HDL-C (coefficient, 0.175) and triglyceride (coefficient, -0.262). However, those correlations disappeared after additional adjustment for BMI. HDL-C alone is unlikely to increase the risk of breast cancer in Korean women, particularly through changes in breast parenchyma that are apparent in mammographic density. BMI should be included in studies using analytical models where mammographic density is used as an intermediate risk factor for breast cancer.

  10. Two Distinct Synchronization Processes in the Transition to Sleep: A High-Density Electroencephalographic Study

    PubMed Central

    Siclari, Francesca; Bernardi, Giulio; Riedner, Brady A.; LaRocque, Joshua J.; Benca, Ruth M.; Tononi, Giulio

    2014-01-01

    affected by experimental manipulations and sleep disorders. Citation: Siclari F, Bernardi G, Riedner BA, LaRocque JJ, Benca RM, Tononi G. Two distinct synchronization processes in the transition to sleep: a high-density electroencephalographic study. SLEEP 2014;37(10):1621-1637. PMID:25197810

  11. Spatially revolved high density electroencephalography

    NASA Astrophysics Data System (ADS)

    Wu, Jerry; Szu, Harold; Chen, Yuechen; Guo, Ran; Gu, Xixi

    2015-05-01

    Electroencephalography (EEG) measures voltage fluctuations resulting from ionic current flows within the neurons of the brain. In practice, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, several tens of minutes, as recorded from multiple electrodes placed on the scalp. In order to improve the resolution and the distortion cause by the hair and scalp, large array magnetoencephalography (MEG) systems are introduced. The major challenge is to systematically compare the accuracy of epileptic source localization with high electrode density to that obtained with sparser electrode setups. In this report, we demonstrate a two dimension (2D) image Fast Fourier Transform (FFT) analysis along with utilization of Peano (space-filling) curve to further reduce the hardware requirement for high density EEG and improve the accuracy and performance of the high density EEG analysis. The brain-computer interfaces (BCIs) in this work is enhanced by A field-programmable gate array (FPGA) board with optimized two dimension (2D) image Fast Fourier Transform (FFT) analysis.

  12. Unisensory processing and multisensory integration in schizophrenia: a high-density electrical mapping study.

    PubMed

    Stone, David B; Urrea, Laura J; Aine, Cheryl J; Bustillo, Juan R; Clark, Vincent P; Stephen, Julia M

    2011-10-01

    In real-world settings, information from multiple sensory modalities is combined to form a complete, behaviorally salient percept - a process known as multisensory integration. While deficits in auditory and visual processing are often observed in schizophrenia, little is known about how multisensory integration is affected by the disorder. The present study examined auditory, visual, and combined audio-visual processing in schizophrenia patients using high-density electrical mapping. An ecologically relevant task was used to compare unisensory and multisensory evoked potentials from schizophrenia patients to potentials from healthy normal volunteers. Analysis of unisensory responses revealed a large decrease in the N100 component of the auditory-evoked potential, as well as early differences in the visual-evoked components in the schizophrenia group. Differences in early evoked responses to multisensory stimuli were also detected. Multisensory facilitation was assessed by comparing the sum of auditory and visual evoked responses to the audio-visual evoked response. Schizophrenia patients showed a significantly greater absolute magnitude response to audio-visual stimuli than to summed unisensory stimuli when compared to healthy volunteers, indicating significantly greater multisensory facilitation in the patient group. Behavioral responses also indicated increased facilitation from multisensory stimuli. The results represent the first report of increased multisensory facilitation in schizophrenia and suggest that, although unisensory deficits are present, compensatory mechanisms may exist under certain conditions that permit improved multisensory integration in individuals afflicted with the disorder.

  13. Irish study of high-density Schizophrenia families: Field methods and power to detect linkage

    SciTech Connect

    Kendler, K.S.; Straub, R.E.; MacLean, C.J.

    1996-04-09

    Large samples of multiplex pedigrees will probably be needed to detect susceptibility loci for schizophrenia by linkage analysis. Standardized ascertainment of such pedigrees from culturally and ethnically homogeneous populations may improve the probability of detection and replication of linkage. The Irish Study of High-Density Schizophrenia Families (ISHDSF) was formed from standardized ascertainment of multiplex schizophrenia families in 39 psychiatric facilities covering over 90% of the population in Ireland and Northern Ireland. We here describe a phenotypic sample and a subset thereof, the linkage sample. Individuals were included in the phenotypic sample if adequate diagnostic information, based on personal interview and/or hospital record, was available. Only individuals with available DNA were included in the linkage sample. Inclusion of a pedigree into the phenotypic sample required at least two first, second, or third degree relatives with non-affective psychosis (NAP), one of whom had schizophrenia (S) or poor-outcome schizoaffective disorder (PO-SAD). Entry into the linkage sample required DNA samples on at least two individuals with NAP, of whom at least one had S or PO-SAD. Affection was defined by narrow, intermediate, and broad criteria. 75 refs., 6 tabs.

  14. Methods for Estimating Environmental Effects and Constraints on NexGen: High Density Case Study

    NASA Technical Reports Server (NTRS)

    Augustine, S.; Ermatinger, C.; Graham, M.; Thompson, T.

    2010-01-01

    This document provides a summary of the current methods developed by Metron Aviation for the estimate of environmental effects and constraints on the Next Generation Air Transportation System (NextGen). This body of work incorporates many of the key elements necessary to achieve such an estimate. Each section contains the background and motivation for the technical elements of the work, a description of the methods used, and possible next steps. The current methods described in this document were selected in an attempt to provide a good balance between accuracy and fairly rapid turn around times to best advance Joint Planning and Development Office (JPDO) System Modeling and Analysis Division (SMAD) objectives while also supporting the needs of the JPDO Environmental Working Group (EWG). In particular this document describes methods applied to support the High Density (HD) Case Study performed during the spring of 2008. A reference day (in 2006) is modeled to describe current system capabilities while the future demand is applied to multiple alternatives to analyze system performance. The major variables in the alternatives are operational/procedural capabilities for airport, terminal, and en route airspace along with projected improvements to airframe, engine and navigational equipment.

  15. Application of spectral line shapes to the study of high density ICF plasmas

    SciTech Connect

    Keane, C.J.; Hammel, B.A.; Langer, S.H.; Lee, R.W.; Calisti, A.; Godbert, L.; Stamm, R.; Talin, B.

    1994-09-01

    Spectral line broadening manifests itself in the study of high density inertial confinement fusion (ICF) plasmas in two important ways. First, comparison between measured and calculated lineshapes of individual spectral lines or groups of lines is used to diagnose plasma conditions in dense ICF plasmas, particularly in implosions. Secondly, through the emission and absorption coefficients spectral lineshapes serve as important inputs to plasma spectroscopy simulation codes which calculate simulated spectra from ICF targets. We discuss recent results from each of these areas. With regard to lineshape diagnostics, the advent of generalized line broadening codes has allowed the line profiles of complex multielectron emitters to be considered for diagnostic purposes. Particular example of this is the use of Ar He-{beta} and its associated dielectronic satellites as a diagnostic of T{sub e} and N{sub e}, as well as the development of Ne-like Xe line broadening as a density diagnostic. With respect to simulation codes, the implementation of detailed lineshapes in calculations of this type is in many ways in its infancy. We present here examples of cases where effects related to spectral lineshapes such as continuum lowering and line transfer of Stark broadened lines are important so as to provide a stimulus for future work in this field. 34 refs., 9 figs., 1 tab.

  16. Inhibitory control and visuo-spatial reversibility in Piaget's seminal number conservation task: a high-density ERP study

    PubMed Central

    Borst, Grégoire; Simon, Grégory; Vidal, Julie; Houdé, Olivier

    2013-01-01

    The present high-density event-related potential (ERP) study on 13 adults aimed to determine whether number conservation relies on the ability to inhibit the overlearned length-equals-number strategy and then imagine the shortening of the row that was lengthened. Participants performed the number-conservation task and, after the EEG session, the mental imagery task. In the number-conservation task, first two rows with the same number of tokens and the same length were presented on a computer screen (COV condition) and then, the tokens in one of the two rows were spread apart (INT condition). Participants were instructed to determine whether the two rows had an identical number of tokens. In the mental imagery task, two rows with different lengths but the same number of tokens were presented and participants were instructed to imagine the tokens in the longer row aligning with the tokens in the shorter row. In the number-conservation task, we found that the amplitudes of the centro-parietal N2 and fronto-central P3 were higher in the INT than in the COV conditions. In addition, the differences in response times between the two conditions were correlated with the differences in the amplitudes of the fronto-central P3. In light of previous results reported on the number-conservation task in adults, the present results suggest that inhibition might be necessary to succeed the number-conservation task in adults even when the transformation of the length of one of the row is displayed. Finally, we also reported correlations between the speed at which participants could imagine the shortening of one of the row in the mental imagery task, the speed at which participants could determine that the two rows had the same number of tokens after the tokens in one of the row were spread apart and the latency of the late positive parietal component in the number-conservation task. Therefore, performing the number-conservation task might involve mental transformation processes in

  17. Using EEG to Study Cognitive Development: Issues and Practices.

    PubMed

    Bell, Martha Ann; Cuevas, Kimberly

    2012-07-10

    Developmental research is enhanced by use of multiple methodologies for examining psychological processes. The electroencephalogram (EEG) is an efficient and relatively inexpensive method for the study of developmental changes in brain-behavior relations. In this review, we highlight some of the challenges for using EEG in cognitive development research. We also list best practices for incorporating this methodology into the study of early cognitive processes. Consideration of these issues is critical for making an informed decision regarding implementation of EEG methodology.

  18. Neonatal hemodynamic response to visual cortex activity: high-density near-infrared spectroscopy study

    NASA Astrophysics Data System (ADS)

    Liao, Steve M.; Gregg, Nick M.; White, Brian R.; Zeff, Benjamin W.; Bjerkaas, Katelin A.; Inder, Terrie E.; Culver, Joseph P.

    2010-03-01

    The neurodevelopmental outcome of neonatal intensive care unit (NICU) infants is a major clinical concern with many infants displaying neurobehavioral deficits in childhood. Functional neuroimaging may provide early recognition of neural deficits in high-risk infants. Near-infrared spectroscopy (NIRS) has the advantage of providing functional neuroimaging in infants at the bedside. However, limitations in traditional NIRS have included contamination from superficial vascular dynamics in the scalp. Furthermore, controversy exists over the nature of normal vascular, responses in infants. To address these issues, we extend the use of novel high-density NIRS arrays with multiple source-detector distances and a superficial signal regression technique to infants. Evaluations of healthy term-born infants within the first three days of life are performed without sedation using a visual stimulus. We find that the regression technique significantly improves brain activation signal quality. Furthermore, in six out of eight infants, both oxy- and total hemoglobin increases while deoxyhemoglobin decreases, suggesting that, at term, the neurovascular coupling in the visual cortex is similar to that found in healthy adults. These results demonstrate the feasibility of using high-density NIRS arrays in infants to improve signal quality through superficial signal regression, and provide a foundation for further development of high-density NIRS as a clinical tool.

  19. Elevated High-Density Lipoprotein Cholesterol and Age-Related Macular Degeneration: The Alienor Study

    PubMed Central

    Cougnard-Grégoire, Audrey; Delyfer, Marie-Noëlle; Korobelnik, Jean-François; Rougier, Marie-Bénédicte; Le Goff, Mélanie; Dartigues, Jean-François; Barberger-Gateau, Pascale; Delcourt, Cécile

    2014-01-01

    Background Lipid metabolism and particularly high-density lipoprotein (HDL) may be involved in the pathogenic mechanism of age-related macular degeneration (AMD). However, conflicting results have been reported in the associations of AMD with plasma HDL and other lipids, which may be confounded by the recently reported associations of AMD with HDL-related genes. We explored the association of AMD with plasma lipid levels and lipid-lowering medication use, taking into account most of HDL-related genes associated with AMD. Methods The Alienor study is a population-based study on age-related eye diseases performed in 963 elderly residents of Bordeaux (France). AMD was graded from non mydriatic color retinal photographs in three exclusive stages: no AMD (n = 430 subjects, 938 eyes); large soft distinct drusen and/or large soft indistinct drusen and/or reticular drusen and/or pigmentary abnormalities (early AMD, n = 176, 247); late AMD (n = 40, 61). Associations of AMD with plasma lipids (HDL, total cholesterol (TC), Low-density lipoprotein (LDL), and triglycerides (TG)) were estimated using Generalized Estimating Equation logistic regressions. Statistical analyses included 646 subjects with complete data. Results After multivariate adjustment for age, sex, educational level, smoking, BMI, lipid-lowering medication use, cardiovascular disease and diabetes, and for all relevant genetic polymorphisms (ApoE2, ApoE4, CFH Y402H, ARMS2 A69S, LIPC rs10468017, LIPC rs493258, LPL rs12678919, ABCA1 rs1883025 and CETP rs3764261), higher HDL was significantly associated with an increased risk of early (OR = 2.45, 95%CI: 1.54–3.90; P = 0.0002) and any AMD (OR = 2.29, 95%CI: 1.46–3.59; P = 0.0003). Association with late AMD was far from statistical significance (OR = 1.58, 95%CI: 0.48–5.17; p = 0.45). No associations were found for any stage of AMD with TC, LDL and TG levels, statin or fibrate drug use. Conclusions This study suggests that

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

    PubMed

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

    2014-08-01

    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.

  1. Electroencephalograph (EEG) study of brain bistable illusion

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  2. FTIR study of the melt grafting of high density polyethylene with amino, sulfonate, and mercapto esters

    NASA Astrophysics Data System (ADS)

    Anbarasan, R.; Dhanalakshmi, V.

    2010-11-01

    High-density polyethylene (HDPE) was melt-functionalized with three different esters at 160oC in the presence of dicumyl peroxide (DCP), a free radical initiator, under nitrogen atmosphere at different % weight loadings of esters. DCP and the esters were taken for the melt functionalization reaction in 1:1 ratio. FTIR spectroscopy was used to determine the % grafting of esters onto the HDPE backbone quantitatively. Diethyl mercaptosuccinate (DEMS) produced the highest % grafting with lowest % cross-linking values, whereas anthranilic acid cinnamoyl ester (AACE) yielded the highest % cross-linking with the lowest % grafting values.

  3. Genome-wide association studies identified novel loci for non-high-density lipoprotein cholesterol and its postprandial lipemic response

    USDA-ARS?s Scientific Manuscript database

    Non-high-density lipoprotein cholesterol (NHDL) is an independent and superior predictor of CVD risk as compared to low-density lipoprotein alone. It represents a spectrum of atherogenic lipid fractions with possibly a distinct genomic signature. We performed genome-wide association studies (GWAS) t...

  4. Novel Changes in Discoidal High Density Lipoprotein Morphology: A Molecular Dynamics Study

    PubMed Central

    Catte, Andrea; Patterson, James C.; Jones, Martin K.; Jerome, W. Gray; Bashtovyy, Denys; Su, Zhengchang; Gu, Feifei; Chen, Jianguo; Aliste, Marcela P.; Harvey, Stephen C.; Li, Ling; Weinstein, Gilbert; Segrest, Jere P.

    2006-01-01

    ApoA-I is a uniquely flexible lipid-scavenging protein capable of incorporating phospholipids into stable particles. Here we report molecular dynamics simulations on a series of progressively smaller discoidal high density lipoprotein particles produced by incremental removal of palmitoyloleoylphosphatidylcholine via four different pathways. The starting model contained 160 palmitoyloleoylphosphatidylcholines and a belt of two antiparallel amphipathic helical lipid-associating domains of apolipoprotein (apo) A-I. The results are particularly compelling. After a few nanoseconds of molecular dynamics simulation, independent of the starting particle and method of size reduction, all simulated double belts of the four lipidated apoA-I particles have helical domains that impressively approximate the x-ray crystal structure of lipid-free apoA-I, particularly between residues 88 and 186. These results provide atomic resolution models for two of the particles produced by in vitro reconstitution of nascent high density lipoprotein particles. These particles, measuring 95 Å and 78 Å by nondenaturing gradient gel electrophoresis, correspond in composition and in size/shape (by negative stain electron microscopy) to the simulated particles with molar ratios of 100:2 and 50:2, respectively. The lipids of the 100:2 particle family form minimal surfaces at their monolayer-monolayer interface, whereas the 50:2 particle family displays a lipid pocket capable of binding a dynamic range of phospholipid molecules. PMID:16581834

  5. Network Efficiency and Posterior Alpha Patterns Are Markers of Recovery from General Anesthesia: A High-Density Electroencephalography Study in Healthy Volunteers

    PubMed Central

    Blain-Moraes, Stefanie; Tarnal, Vijay; Vanini, Giancarlo; Bel-Behar, Tarik; Janke, Ellen; Picton, Paul; Golmirzaie, Goodarz; Palanca, Ben J. A.; Avidan, Michael S.; Kelz, Max B.; Mashour, George A.

    2017-01-01

    Recent studies have investigated local oscillations, long-range connectivity, and global network patterns to identify neural changes associated with anesthetic-induced unconsciousness. These studies typically employ anesthetic protocols that either just cross the threshold of unconsciousness, or induce deep unconsciousness for a brief period of time—neither of which models general anesthesia for major surgery. To study neural patterns of unconsciousness and recovery in a clinically-relevant context, we used a realistic anesthetic regimen to induce and maintain unconsciousness in eight healthy participants for 3 h. High-density electroencephalogram (EEG) was acquired throughout and for another 3 h after emergence. Seven epochs of 5-min eyes-closed resting states were extracted from the data at baseline as well as 30, 60, 90, 120, 150, and 180-min post-emergence. Additionally, 5-min epochs were extracted during induction, unconsciousness, and immediately prior to recovery of consciousness, for a total of 10 analysis epochs. The EEG data in each epoch were analyzed using source-localized spectral analysis, phase-lag index, and graph theoretical techniques. Posterior alpha power was significantly depressed during unconsciousness, and gradually approached baseline levels over the 3 h recovery period. Phase-lag index did not distinguish between states of consciousness or stages of recovery. Network efficiency was significantly depressed and network clustering coefficient was significantly increased during unconsciousness; these graph theoretical measures returned to baseline during the 3 h recovery period. Posterior alpha power may be a potential biomarker for normal recovery of functional brain networks after general anesthesia. PMID:28701933

  6. Using EEG to Study Cognitive Development: Issues and Practices

    ERIC Educational Resources Information Center

    Bell, Martha Ann; Cuevas, Kimberly

    2012-01-01

    Developmental research is enhanced by use of multiple methodologies for examining psychological processes. The electroencephalogram (EEG) is an efficient and relatively inexpensive method for the study of developmental changes in brain-behavior relations. In this review, we highlight some of the challenges for using EEG in cognitive development…

  7. Using EEG to Study Cognitive Development: Issues and Practices

    ERIC Educational Resources Information Center

    Bell, Martha Ann; Cuevas, Kimberly

    2012-01-01

    Developmental research is enhanced by use of multiple methodologies for examining psychological processes. The electroencephalogram (EEG) is an efficient and relatively inexpensive method for the study of developmental changes in brain-behavior relations. In this review, we highlight some of the challenges for using EEG in cognitive development…

  8. Disabling conditional inferences: an EEG study.

    PubMed

    Bonnefond, Mathilde; Kaliuzhna, Mariia; Van der Henst, Jean-Baptiste; De Neys, Wim

    2014-04-01

    Although the Modus Ponens inference is one of the most basic logical rules, decades of conditional reasoning research show that it is often rejected when people consider stored background knowledge about potential disabling conditions. In the present study we used EEG to identify neural markers of this process. We presented participants with many and few disabler conditionals for which retrieval of disabling conditions was likely or unlikely. As in classic behavioral studies we observed that participants accepted the standard MP conclusion less for conditionals with many disablers. The key finding was that the presentation of the standard MP conclusion also resulted in a more pronounced N2 and less pronounced P3b for the many disabler conditionals. This specific N2/P3b pattern has been linked to the violation and satisfaction of expectations, respectively. Thereby, the present ERP findings support the idea that disabler retrieval lowers reasoners' expectations that the standard MP conclusion can be drawn.

  9. Isotopic studies of high-density interstellar graphite from the Murchison meteorite

    NASA Astrophysics Data System (ADS)

    Amari, S.; Zinner, E.; Lewis, R. S.

    1994-07-01

    We continue with multielement isotopic analyses of single graphite grains from various density fractions extracted from Murchison. Previous measurements have shown that different density fractions have different isotopic ratios and trace-element contents, suggesting multiple stellar sources for interstellar graphite. One goal is to identify these stellar sources. In this work we report isotopic ratios of graphite grains from the high-density fraction KFC1 (2.15-2.20 g/cu cm, greater than 1 micron) and compare them with results on the low-density fraction KE3 (1.68-1.71 g/cu cm, greater than 3 microns). To be able to obtain multielement isotopic data, we chose larger grains. Forty-five grains were analyzed for their C and N isotopic ratios and the C and N isotopic compositions of KFC1 and KE3 are plotted. As previously observed, most grains in this fraction have isotopically light C. Only three grains have heavy N with N-14/N-15 ratios less than 250 (2 sigma) (solar ratio; 272). The others have normal N. Of 40 grains measured for their O-18/O-16 ratios, all have normal ratios within errors. This is in contrast to graphite grains from KE3, of which two-thirds have O-18 excesses that range up to 100 times solar. Since large O-18 excesses can be generated in massive stars such as Wolf Rayet stars or supernovae, the O-18 excesses in KE3 suggest that a large fraction of low-density graphite grains originate from massive stars, while the contribution from massive stars is small to negligible in the high-density fraction KFC1. This agrees with the conclusions derived from Kr isotopic ratios for these fractions. A striking difference between the density fractions can also be seen for Al-26/Al-27 ratios. The Kr isotopic ratios measured in KFC1 suggest that AGB stars of low metallicity contributed high-density graphite grains.

  10. Studies of challenge in lower hybrid current drive capability at high density regime in experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Ding, B. J.; Li, M. H.; Li, Y. C.; Wang, M.; Liu, F. K.; Shan, J. F.; Li, J. G.; Wan, B. N.

    2017-02-01

    Aiming at a fusion reactor, two issues must be solved for the lower hybrid current drive (LHCD), namely good lower hybrid wave (LHW)-plasma coupling and effective current drive at high density. For this goal, efforts have been made to improve LHW-plasma coupling and current drive capability at high density in experimental advanced superconducting tokamak (EAST). LHW-plasma coupling is improved by means of local gas puffing and gas puffing from the electron side is taken as a routine way for EAST to operate with LHCD. Studies of high density experiments suggest that low recycling and high lower hybrid (LH) frequency are preferred for LHCD experiments at high density, consistent with previous results in other machines. With the combination of 2.45 GHz and 4.6 GHz LH waves, a repeatable high confinement mode plasma with maximum density up to 19~\\text{m}-3$ was obtained by LHCD in EAST. In addition, in the first stage of LHCD cyclic operation, an alternative candidate for more economical fusion reactors has been demonstrated in EAST and further work will be continued.

  11. Study on Electrodeless Electric Propulsion in High-Density Helicon Plasma with Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Ishii, Takamichi; Ishii, Hiroki; Otsuka, Shuhei; Teshigahara, Naoto; Fujitsuka, Hiroaki; Waseda, Shimpei; Kuwahara, Daisuke; Shinohara, Shunjiro

    To establish electrodeless electric propulsion, we have been developing a new electrodeless plasma acceleration thruster using high-density helicon plasmas and permanent magnets, and characterizing them by, e.g., electrostatic and magnetic probes, a high-resolution spectrometer (measuring argon line intensity and line intensity ratio to derive plasma parameters), and a high-speed camera measurements (deriving radial distribution of electron density), in addition to a laser induced fluorescence (LIF) method to measure plasma flow velocity, where they are under development. Here, we will present preliminary acceleration methods using such as Rotating Magnetic Field coil and m = 0 coil along with results of various measurements mentioned above to estimate the plasma performance.

  12. Comparative EEG mapping studies in Huntington's disease patients and controls.

    PubMed

    Painold, Annamaria; Anderer, Peter; Holl, Anna K; Letmaier, Martin; Saletu-Zyhlarz, Gerda M; Saletu, Bernd; Bonelli, Raphael M

    2010-11-01

    Huntington's disease (HD) is a devastating neurodegenerative disorder with prominent motor and cognitive decline. Previous studies with small sample sizes and methodological limitations have described abnormal electroencephalograms (EEG) in this cohort. The aim of the present study was to investigate objectively and quantitatively the neurophysiological basis of the disease in HD patients as compared to normal controls, utilizing EEG mapping. In 55 HD patients and 55 healthy controls, a 3-min vigilance-controlled EEG (V-EEG) was recorded during midmorning hours. Evaluation of 36 EEG variables was carried out by spectral analysis and visualized by EEG mapping techniques. To elucidate drug interference, the analysis was performed for the total group, unmedicated patients only and between treated and untreated patients. Statistical overall analysis by the omnibus significance test demonstrated significant (p < 0.01 and p < 0.05) EEG differences between HD patients and controls. Subsequent univariate analysis revealed a general decrease in total power and absolute alpha and beta power, an increase in delta/theta power, and a slowing of the centroids of delta/theta, beta and total power. The slowing of the EEG in HD reflects a disturbed brain function in the sense of a vigilance decrement, electrophysiologically characterized by inhibited cortical areas (increased delta/theta power) and a lack of normal routine and excitatory activity (decreased alpha and beta power). The results are similar to those found in other dementing disorders. Medication did not affect the overall interpretation of the quantitative EEG analysis, but certain differences might be due to drug interaction, predominantly with antipsychotics. Spearman rank correlations revealed significant correlations between EEG mapping and cognitive and motor impairment in HD patients.

  13. Plasma detachment study of high density helium plasmas in the Pilot-PSI device

    NASA Astrophysics Data System (ADS)

    Hayashi, Y.; Ješko, K.; van der Meiden, H. J.; Vernimmen, J. W. M.; Morgan, T. W.; Ohno, N.; Kajita, S.; Yoshikawa, M.; Masuzaki, S.

    2016-12-01

    We have investigated plasma detachment phenomena of high-density helium plasmas in the linear plasma device Pilot-PSI, which can realize a relevant ITER SOL/Divertor plasma condition. The experiment clearly indicated plasma detachment features such as drops in the plasma pressure and particle flux along the magnetic field lines that were observed under the condition of high neutral pressure; a feature of flux drop was parameterized using the degree of detachment (DOD) index. Fundamental plasma parameters such as electron temperature (T e) and electron density in the detached recombining plasmas were measured by different methods: reciprocating electrostatic probes, Thomson scattering (TS), and optical emission spectroscopy (OES). The T e measured using single and double probes corresponded to the TS measurement. No anomalies in the single probe I-V characteristics, observed in other linear plasma devices [16, 17, 36], appeared under the present condition in the Pilot-PSI device. A possible reason for this difference is discussed by comparing the different linear devices. The OES results are also compared with the simulation results of a collisional radiative (CR) model. Further, we demonstrated more than 90% of parallel particle and heat fluxes were dissipated in a short length of 0.5 m under the high neutral pressure condition in Pilot-PSI.

  14. Altered response-preparation in patients with adult ADHD: A high-density ERP study.

    PubMed

    Kakuszi, Brigitta; Tombor, László; Papp, Szilvia; Bitter, István; Czobor, Pál

    2016-03-30

    Aberrations in early-developing bottom-up processes, such as stimulus-driven response preparation, are thought to play a critical role in the onset of ADHD, and in its persistence over time. Electrophysiology offers a unique tool to gain insight into response preparation, since response preparation has been associated with distinctive ERP changes, including negative potential-shifts which occur predominantly over frontal brain areas. We examined response-preceding negative potential shifts (RPNS) as a probe of response-preparation in adult ADHD patients by obtaining high-density event-related potentials from 33 ADHD and 29 matched healthy subjects during a Go/Nogo task using a 128-channel BioSemi recording-system. Compared to controls, ADHD patients showed enhancement of the RPNS in fronto-central brain regions in the Go condition during correct responses. This change was associated with poor performance in the Stroop incongruency-task: the greater the enhancement, the higher the proportion of errors. Moreover, the ERP-enhancement showed association with the severity of ADHD-symptoms; and with heightened response-variability. Thus, ADHD patients demonstrate neurophysiological alterations in response-preparation and response-preceding brain activity, suggestive of excessive activation of prefrontal neural circuits. Given the correlation with neuropsychological and psychopathological measures, these changes may constitute a pathway for core symptoms of ADHD, including premature and impaired response-preparation and motor-hyperactivity.

  15. Executive Dysfunction and Reward Dysregulation: A High-Density Electrical Mapping Study in Cocaine Abusers

    PubMed Central

    Morie, Kristen P.; De Sanctis, Pierfilippo; Garavan, Hugh; Foxe, John J.

    2015-01-01

    Executive function deficits and reward dysregulation, which mainly manifests as anhedonia, are well documented in drug abusers. We investigated specific aspects of executive function (inhibitory control and cognitive control), as well as anhedonia, in a cohort of current cocaine abusers in order to ascertain to what extent these factors are associated with more severe drug dependence. Participants filled out questionnaires relating to anhedonia and their addiction history. Participants also performed a response inhibition task while high-density event-related potentials (ERPs) were recorded. Electrophysiological responses to successful inhibitions (N2/P3 components) and to commission errors (ERN/Pe components) were compared between 23 current users of cocaine and 27 non-using controls. A regression model was performed to determine the association of our measures of reward dysregulation and executive function with addiction severity. As expected, cocaine users performed more poorly than controls on the inhibitory control task and showed significant electrophysiological differences. They were also generally more anhedonic than controls. Higher levels of anhedonia were associated with more severe substance use, whereas the level of executive dysfunction was not associated with more severe substance use. However, N2 amplitude was associated with duration of drug use. Further, inhibitory control and anhedonia were correlated, but only in controls. These data suggest that while executive dysfunction characterizes drug abuse, it is anhedonia, independent of executive dysfunction, that is most strongly associated with more severe use. PMID:24911989

  16. Riboflavin crosslinked high-density collagen gel for the repair of annular defects in intervertebral discs: An in vivo study.

    PubMed

    Grunert, Peter; Borde, Brandon H; Towne, Sara B; Moriguchi, Yu; Hudson, Katherine D; Bonassar, Lawrence J; Härtl, Roger

    2015-10-01

    Open annular defects compromise the ability of the annulus fibrosus to contain nuclear tissue in the disc space, and therefore lead to disc herniation with subsequent degenerative changes to the entire intervertebral disc. This study reports the use of riboflavin crosslinked high-density collagen gel for the repair of annular defects in a needle-punctured rat-tail model. High-density collagen has increased stiffness and greater hydraulic permeability than conventional low-density gels; riboflavin crosslinking further increases these properties. This study found that treating annular defects with crosslinked high-density collagen inhibited the progression of disc degeneration over 18 weeks compared to untreated control discs. Histological sections of FITC-labeled collagen gel revealed an early tight attachment to host annular tissue. The gel was subsequently infiltrated by host fibroblasts which remodeled it into a fibrous cap that bridged the outer disrupted annular fibers and partially repaired the defect. This repair tissue enhanced retention of nucleus pulposus tissue, maintained physiological disc hydration, and preserved hydraulic permeability, according to MRI, histological, and mechanical assessments. Degenerative changes were partially reversed in treated discs, as indicated by an increase in nucleus pulposus size and hydration between weeks 5 and 18. The collagen gel appeared to work as an instant sealant and by enhancing the intrinsic healing capabilities of the host tissue.

  17. Ear-EEG from generic earpieces: a feasibility study.

    PubMed

    Kidmose, P; Looney, D; Jochumsen, L; Mandic, D P

    2013-01-01

    The use of brain monitoring based on EEG, in natural environments and over long time periods, is hindered by the limited portability of current wearable systems, and the invasiveness of implanted systems. To that end, we introduce an ear-EEG recording device based on generic earpieces which meets key patient needs (discreet, unobstrusive, user-friendly, robust) and that is low-cost and suitable for off-the-shelf use; thus promising great advantages for healthcare applications. Its feasibility is validated in a comprehensive comparative study with our established prototype, based on a personalized earpiece, for a key EEG paradigm.

  18. The chronoarchitecture of human sexual desire: a high-density electrical mapping study.

    PubMed

    Ortigue, Stephanie; Bianchi-Demicheli, Francesco

    2008-11-01

    Recent neuroimaging research suggests that human sexual desire (SD) recruits both the limbic system and higher-order cognitive brain areas. Because of the temporal limitation of this technique, the chronoarchitecture of SD remains however unresolved. Here, we investigated the spatio-temporal dynamics of SD by combining a behavioral desire decision task with high-density visual event-related potential (VEP) recordings and brain source estimations. VEPs were recorded from thirteen healthy participants when presented with pictures from two different stimulus categories (i.e., high and low desirability). In agreement with the literature, behavioral results showed that participants were faster to rate non-desired stimuli than desired stimuli (p=0.028). Electrophysiological results extended these behavioral data. Group-averaged VEPs peaked at 90 to 140 ms (P100), at 142 to 220 ms (N200), and at 222 to 360 ms (P300). Desired stimuli (DS) were distinguished from non-desired stimuli (NDS) over the N200 period, notably from 142 to 187 ms. Over this time period, DS processing was characterized by a significant scalp potential field. Although both conditions (DS and NDS) showed the recruitment of the occipito-temporal region (including the extrastriate body area, EBA), LAURA source estimation of the DS scalp potential field revealed a more right-lateralized current source density maximum in the posterior superior temporal sulcus (STS) extending to the temporo-parietal junction (TPJ). The recruitment of STS and TPJ for desired stimuli indicates that these brain areas, known to be respectively involved in social cognition, attention, integration of body-related information and self-processing, play a crucial role for the coding of desirability of visual sexual human stimuli within the first 200 ms after stimulus onset. These findings support the hypothesis that complex cognitive processing for desire occurs much faster than previously thought and open new perspectives with

  19. An EEG-based study of discrete isometric and isotonic human lower limb muscle contractions

    PubMed Central

    2012-01-01

    Background Electroencephalography (EEG) combined with independent component analysis enables functional neuroimaging in dynamic environments including during human locomotion. This type of functional neuroimaging could be a powerful tool for neurological rehabilitation. It could enable clinicians to monitor changes in motor control related cortical dynamics associated with a therapeutic intervention, and it could facilitate noninvasive electrocortical control of devices for assisting limb movement to stimulate activity dependent plasticity. Understanding the relationship between electrocortical dynamics and muscle activity will be helpful for incorporating EEG-based functional neuroimaging into clinical practice. The goal of this study was to use independent component analysis of high-density EEG to test whether we could relate electrocortical dynamics to lower limb muscle activation in a constrained motor task. A secondary goal was to assess the trial-by-trial consistency of the electrocortical dynamics by decoding the type of muscle action. Methods We recorded 264-channel EEG while 8 neurologically intact subjects performed isometric and isotonic, knee and ankle exercises at two different effort levels. Adaptive mixture independent component analysis (AMICA) parsed EEG into models of underlying source signals. We generated spectrograms for all electrocortical source signals and used a naïve Bayesian classifier to decode exercise type from trial-by-trial time-frequency data. Results AMICA captured different electrocortical source distributions for ankle and knee tasks. The fit of single-trial EEG to these models distinguished knee from ankle tasks with 80% accuracy. Electrocortical spectral modulations in the supplementary motor area were significantly different for isometric and isotonic tasks (p < 0.05). Isometric contractions elicited an event related desynchronization (ERD) in the α-band (8–12 Hz) and β-band (12–30 Hz) at joint torque onset and

  20. Navigating abstract virtual environment: an eeg study.

    PubMed

    Hakak, Alireza Mahdizadeh; Bhattacharya, Joydeep; Biloria, Nimish; de Kleijn, Roy; Shah-Mohammadi, Fanak

    2016-12-01

    Perceptions of different environments are different for different people. An abstract designed environment, with a degree of freedom from any visual reference in the physical world requests a completely different perception than a fully or semi-designed environment that has some correlation with the physical world. Maximal evidence on the manner in which the human brain is involved/operates in dealing with such novel perception comes from neuropsychology. Harnessing the tools and techniques involved in the domain of neuropsychology, the paper presents nee evidence on the role of pre-central gyrus in the perception of abstract spatial environments. In order to do so, the research team developed three different categories of designed environment with different characteristics: (1) Abstract environment, (2) Semi-designed environment, (3) Fully designed environment, as experimental sample environments. Perception of Fully-designed and semi-designed environments is almost the same, [maybe] since the brain can find a correlation between designed environments and already experienced physical world. In addition to this, the response to questionnaires accompanied with a list of buzzwords that have been provided after the experiments, also describe the characteristics of the chosen sample environments. Additionally, these results confirm the suitability of continuous electroencephalography (EEG) for studying Perception from the perspective of architectural environments.

  1. The default mode network and EEG regional spectral power: a simultaneous fMRI-EEG study.

    PubMed

    Neuner, Irene; Arrubla, Jorge; Werner, Cornelius J; Hitz, Konrad; Boers, Frank; Kawohl, Wolfram; Shah, N Jon

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  3. Individualising EEG frequency bands for sleep deprivation studies.

    PubMed

    Henelius, Andreas; Korpela, Jussi; Huotilainen, Minna

    2011-01-01

    A method for determining individualised frequency bands from electroencephalographic (EEG) power spectral density (PSD) plots is presented. EEG was collected during the performance of a computerised multitask test from 21 healthy male subjects, of which an experimental group of 14 subjects underwent sleep deprivation and 7 subjects formed the control group. EEG PSD plots were compared between the groups and were used to determine individual theta, alpha and beta bands for the subjects by studying the points of intersection between the individual subjects' normalised spectra and the normalised average spectrum of the control group. The results show that the frontal and occipital locations are best suited for the determination of individualised frequency bands. The proposed method can be used to enhance EEG spectral analysis of task-induced cognitive effort during sleep deprivation.

  4. Thermal and optical excitation of trapped electrons in high-density polyethylene (HDPE) studied through positron annihilation

    NASA Astrophysics Data System (ADS)

    Nahid, F.; Zhang, J. D.; Yu, T. F.; Ling, C. C.; Fung, S.; Beling, C. D.

    2011-04-01

    Positronium (Ps) formation in high-density polyethylene (HDPE) has been studied below the glass transition temperature. The formation probability increases with positron irradiation time due to an increasing number of inter-track trapped electrons becoming available for positron capture. The temperature variation of the saturated Ps level is discussed in different models. The quenching of trapped electrons by light has been studied and the optical de-trapping cross-section for different photon energies has been estimated over the visible region.

  5. [Study on biocompatibility of hydroxyapatite/high density polyethylene (HA/HDPE) nano-composites artificial ossicle].

    PubMed

    Wang, Guohui; Zhu, Shaihong; Tan, Guolin; Zhou, Kechao; Huang, Suping; Zhao, Yanzhong; Li, Zhiyou; Huang, Boyun

    2008-06-01

    This study was aimed to evaluate the biocompatibility of Hydroxyapatite/High density polyethylene (HA/ HDPE) nano-composites artificial ossicle. The percentage of S-period cells were detected by flow cytometry after L929 cells being incubated with extraction of the HA/HDPE nano-composites; the titanium materials for clinical application served as the contrast. In addition, both materials were implanted in animals and the histopathological evaluations were conducted. There were no statistically significant differences between the two groups (P >0.05). The results demonstrated that the HA/HDPE nano-composite artificial ossicle made by our laboratory is of a good biocompatibility and clinical application outlook.

  6. Reward Contingencies and the Recalibration of Task Monitoring and Reward Systems: A high-density electrical mapping study

    PubMed Central

    Morie, Kristen P.; De Sanctis, Pierfilippo; Foxe, John J.

    2014-01-01

    Task execution almost always occurs in the context of reward-seeking or punishment-avoiding behavior. As such, ongoing task monitoring systems are influenced by reward anticipation systems. In turn, when a task has been executed either successfully or unsuccessfully, future iterations of that task will be re-titrated on the basis of the task outcome. Here, we examined the neural underpinnings of the task-monitoring and reward-evaluation systems to better understand how they govern reward seeking behavior. Twenty-three healthy adult participants performed a task where they accrued points that equated to real world value (gift cards) by responding as rapidly as possible within an allotted timeframe, while success rate was titrated online by changing the duration of the timeframe dependent on participant performance. Informative cues initiated each trial, indicating the probability of potential reward or loss (four levels from very low to very high). We manipulated feedback by first informing participants of task success/failure, after which a second feedback signal indicated actual magnitude of reward/loss. High-density EEG recordings allowed for examination of event-related potentials (ERPs) to the informative cues and in turn, to both feedback signals. Distinct ERP components associated with reward cues, task preparatory and task monitoring processes, and reward feedback processes were identified. Unsurprisingly, participants displayed increased ERP amplitudes associated with task preparatory processes following cues that predicted higher chances of reward. They also rapidly updated reward and loss prediction information dependent on task performance after the first feedback signal. Finally, upon reward receipt, initial reward probability was no longer taken into account. Rather, ERP measures suggested that only the magnitude of actual reward or loss was now processed. Reward and task monitoring processes are clearly dissociable, but interact across very fast

  7. On the "dependence" of "independent" group EEG sources; an EEG study on two large databases.

    PubMed

    Congedo, Marco; John, Roy E; De Ridder, Dirk; Prichep, Leslie; Isenhart, Robert

    2010-06-01

    The aim of this work is to study the coherence profile (dependence) of robust eyes-closed resting EEG sources isolated by group blind source separation (gBSS). We employ a test-retest strategy using two large sample normative databases (N = 57 and 84). Using a BSS method in the complex Fourier domain, we show that we can rigourously study the out-of-phase dependence of the extracted components, albeit they are extracted so as to be in-phase independent (by BSS definition). Our focus on lagged communication between components effectively yields dependence measures unbiased by volume conduction effects, which is a major concern about the validity of any dependence measures issued by EEG measurements. We are able to show the organization of the extracted components in two networks. Within each network components oscillate coherently with multiple-frequency dynamics, whereas between networks they exchange information at non-random multiple time-lag rates.

  8. Study of short haul high-density V/STOL transportation systems. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    Solomon, H. L.

    1972-01-01

    Essential supporting data to the short haul transportation study are presented. The specific appendices are arena characteristics, aerospace transportation analysis computer program, economics, model calibration, STOLport siting and services path selection, STOL schedule definition, tabulated California corridor results, and tabulated Midwest arena results.

  9. Porous high-density polyethylene in facial reconstruction and revision rhinoplasty: a prospective cohort study

    PubMed Central

    2012-01-01

    Introduction Initial methods which used human tissues as reconstruction materials caused different problems including rejection, limited shapes and infection. In 1970s, PHDPE (Medpor®) was introduced by its exclusive advantageous including no donor site morbidity, easily shaped and the minimal foreign body reaction. Hereby, we report our experience of using Medpor® in facial reconstruction especially in frontal reconstruction and orbital rim with a large sample size. Methods This study was a prospective cohort study. Surgical techniques included using Medpor® in reconstruction of lamina papiracea (LP) (15 patients), frontal bone (15 patients), orbital rim (18 patients) and open rhinoplasty (8 patients). All interventions on LP were performed by endoscopic procedures. All frontal operations were carried out by bicoronal incision. In orbital defects, we used subciliary incision. Results From all 56 patients, 1 case had primitive neuroectodermal tumor (PNET) of maxillary sinus. In that case, reconstruction of inferior orbital rim was not successful and extrusion was occurred after radiotherapy. In rhinoplasty and other experiences no extrusion or infection were detected within the next 1 to 3 years of follow up. There were not any palpable and visible irregularities under the skin in our experiences. Conclusions In this study the patients did not experience any complications during the follow up periods and the satisfaction was remarkable. Gathering these data gives rise to future review studies which can provide more organized evidences for replacing classic reconstructive methods by the presented material. PMID:22642753

  10. A molecular dynamics study of structure and dynamics in high-density liquids

    NASA Astrophysics Data System (ADS)

    Variyar, Jayasankar E.; Noro, Massimo; Kivelson, Daniel

    By means of molecular dynamics simulations we have investigated increasing configurational ordering and decreasing particle mobility with increasing density ρ of a three-dimensional equilibrated liquid composed of soft discs. The equal-time correlation function h(n)3 (0) which includes two-, three- and four-body correlations is introduced as a measure of structural order; this function is related to the dipole-induced-dipole equal-time correlation function and its sensitivity to structural order in the liquid is associated with the cancellation effect, i.e. the cancellation of the positive contributions of the two- and four- body correlations by the negative contribution of the three-body correlations. The analogous time-dependent correlation function h(4)3 (t) is also studied. The possible implications of these results to the study of supercooled liquids and glasses is discussed.

  11. A molecular dynamics study of structure and dynamics in high-density liquids

    NASA Astrophysics Data System (ADS)

    Variyar, Jayasankar E.; Kivelson, Daniel

    By means of molecular dynamics simulations we have investigated increasing configurational ordering and decreasing particle mobility with increasing density ρ of a two-dimensional equilibrated liquid composed of soft discs. An equaltime correlation function h(3)2 (0) which includes three-body, as well as two-body, correlations is introduced as a measure of structural order; this function is related to the dipole-induced-dipole equal-time correlation function h(4)2 (0), and its sensitivity to structural order in the liquid is associated with the cancellation effect, the cancellation of the positive contribution of the two-body correlations by the negative contribution of the three-body correlations. The analogous time-dependent correlation function h(3)2 (t) is also studied. The possible implications of these results for the study of supercooled liquids and glasses is discussed.

  12. Neurophysiologic Correlates of Ketamine Sedation and Anesthesia: A High-density Electroencephalography Study in Healthy Volunteers.

    PubMed

    Vlisides, Phillip E; Bel-Bahar, Tarik; Lee, UnCheol; Li, Duan; Kim, Hyoungkyu; Janke, Ellen; Tarnal, Vijay; Pichurko, Adrian B; McKinney, Amy M; Kunkler, Bryan S; Picton, Paul; Mashour, George A

    2017-07-01

    Previous studies have demonstrated inconsistent neurophysiologic effects of ketamine, although discrepant findings might relate to differences in doses studied, brain regions analyzed, coadministration of other anesthetic medications, and resolution of the electroencephalograph. The objective of this study was to characterize the dose-dependent effects of ketamine on cortical oscillations and functional connectivity. Ten healthy human volunteers were recruited for study participation. The data were recorded using a 128-channel electroencephalograph during baseline consciousness, subanesthetic dosing (0.5 mg/kg over 40 min), anesthetic dosing (1.5 mg/kg bolus), and recovery. No other sedative or anesthetic medications were administered. Spectrograms, topomaps, and functional connectivity (weighted and directed phase lag index) were computed and analyzed. Frontal theta bandwidth power increased most dramatically during ketamine anesthesia (mean power ± SD, 4.25 ± 1.90 dB) compared to the baseline (0.64 ± 0.28 dB), subanesthetic (0.60 ± 0.30 dB), and recovery (0.68 ± 0.41 dB) states; P < 0.001. Gamma power also increased during ketamine anesthesia. Weighted phase lag index demonstrated theta phase locking within anterior regions (0.2349 ± 0.1170, P < 0.001) and between anterior and posterior regions (0.2159 ± 0.1538, P < 0.01) during ketamine anesthesia. Alpha power gradually decreased with subanesthetic ketamine, and anterior-to-posterior directed connectivity was maximally reduced (0.0282 ± 0.0772) during ketamine anesthesia compared to all other states (P < 0.05). Ketamine anesthesia correlates most clearly with distinct changes in the theta bandwidth, including increased power and functional connectivity. Anterior-to-posterior connectivity in the alpha bandwidth becomes maximally depressed with anesthetic ketamine administration, suggesting a dose-dependent effect.

  13. The Horsehead Nebula: a template for extragalactic high density tracers studies?

    NASA Astrophysics Data System (ADS)

    Gratier, P.; Pety, J.; Gerin, M.; Montillaud, J.; Guzman, V.; Goicoechea, J. R.

    2011-05-01

    The Horsehead Nebula, thanks to its proximity (1'' = 0.002 pc) and simple geometry is a perfect benchmark case to study the interplay between structure and chemistry in PDRs (Photon Dominated Regions). Our past studies of many tracers enabled us to obtain a clear picture of the density and temperature structure of the region. The presence of a steep density gradient (from less than 10^3 cm-3 to 10^5 cm-3 in less than 10'' = 0.02 pc) allows to probe different environments, from far-UV photon-dominated regions to shielded cold gas, in less than 50''. With the increased sensitivity available, extragalactic observations of gas tracers other than CO such as HCN, HNC, HCO^+ become more common. These observations are used in the extragalactic context to probe the density of the interstellar medium, to identify the heating mechanisms : FUV photons --- related to starburst phenomena, whose interaction with the ISM can be understood using PDR models ) or X rays --- related to AGN, using XDR models ---, and to probe star formation using specific molecular lines as tracers of embedded star forming regions. Nevertheless these observations are of low linear resolution and the details of the physics and chemistry of the interstellar medium are smeared by averaging over different environments. We will study how the understanding of these tracers in well known Galactic environments, such as the Horsehead PDR, can help the interpretation of extragalactic observations. We present high resolution multiline observations of HCN, HNC, CN and HCO^+ by the IRAM PdBI and 30m telescope instruments. We study the emission line ratios of these different molecules with the objective of comparing these high resolution observations of a well characterized Galactic region to extragalactic observations of the same tracers. Among the questions raised are : What is the importance of hyperfine anomalies in understanding the HCN and HNC observations? Can HCN be used as a tracer of star formation at

  14. Monoclonal antibodies to human apolipoproteins: application to the study of high density lipoprotein subpopulations.

    PubMed

    Bustos, P; Ulloa, N; Calvo, C; Muller, D; Durán, D; Martínez, J; Salazar, L; Quiroga, A

    2000-09-01

    We produced, selected and cloned hybridomas that secrete monoclonal antibodies against human apolipoprotein (apo) A-I. All of the antibodies corresponded to the IgG(1) subclass and were named 1C11, 2B4, 2C10, 7C5, 8A4 and 8A5. The antibodies were characterized by their reactivity with whole lipoproteins, apolipoproteins, synthetic peptides and fragments generated by cleavage of the apo A-I. Three of the monoclonal antibodies studied (2B4, 2C10 and 7C5) were similarly inhibited by an amino-terminal peptide (amino acid sequence 1-20) of apo A-I, whereas antibodies 1C11, 8A4 and 8A5 had no reaction. Other results show that monoclonal antibody 1C11 recognizes an epitope located between amino acids 135-148. We evaluated the monoclonal antibody 8A4 against different HDL subpopulations by competitive displacement analysis and it showed a similar reactivity with the HDL particles: LpA-I and LpA-I:A-II. This antibody was used to standardize a sandwich ELISA to quantitate LpA-I in plasma. We conclude that these monoclonal antibodies are relevant for the study of apo A-I epitope expression and for quantitating apo A-I containing lipoparticles.

  15. Photo- and biophysical studies of lectin-conjugated fluorescent nanoparticles: reduced sensitivity in high density assays.

    PubMed

    Wang, Yaqi; Gildersleeve, Jeffrey C; Basu, Amit; Zimmt, Matthew B

    2010-11-18

    Lectin-conjugated, fluorescent silica nanoparticles (fNP) have been developed for carbohydrate-based histopathology evaluations of epithelial tissue biopsies. The fNP platform was selected for its enhanced emissive brightness compared to direct dye labeling. Carbohydrate microarray studies were performed to compare the carbohydrate selectivity of the mannose-recognizing lectin Concanavalin A (ConA) before and after conjugation to fluorescent silica nanoparticles (ConA-fNP). These studies revealed surprisingly low emission intensities upon staining with ConA-fNP compared to those with biotin-ConA/Cy3-streptavidin staining. A series of photophysical and biophysical characterizations of the fNP and ConA-fNP conjugates were performed to probe the low sensitivity from fNP in the microarray assays. Up to 1200 fluorescein (FL) and 80 tetramethylrhodamine (TR) dye molecules were incorporated into 46 nm diameter fNP, yielding emissive brightness values 400 and 35 times larger than the individual dye molecules, respectively. ConA lectin conjugated to carboxylic acid surface-modified nanoparticles covers 15-30% of the fNP surface. The CD spectra and mannose substrate selectivity of ConA conjugated to the fNP differed slightly compared to that of soluble ConA. Although, the high emissive brightness of fNP enhances detection sensitivity for samples with low analyte densities, large fNP diameters limit fNP recruitment and binding to samples with high analyte densities. The high analyte density and nearly two-dimensional target format of carbohydrate microarrays make probe size a critical parameter. In this application, fNP labels afford minimal sensitivity advantage compared to direct dye labeling.

  16. State-dependent attention modulation of human primary visual cortex: a high density ERP study.

    PubMed

    Rossi, Valentina; Pourtois, Gilles

    2012-05-01

    Converging electrophysiological and brain-imaging results show that sensory processing in V1 can be modulated by attention. In this study, we tested the prediction that this early filtering effect depends on the current affective state of the participant. We recorded visual evoked potentials (VEPs) to visual peripheral distractors while participants performed a demanding task at fixation, whose perceptual load was manipulated in a parametric fashion. Crucially, levels of negative affect were either increased or decreased independently of changes in perceptual load. Concurrent psychophysiological measurements and self-report scales confirmed that changes in emotional state were effective. In the control condition, ERP results showed that the C1 component generated in response to the exact same peripheral distractors systematically varied in amplitude with the amount of perceptual load imposed at fixation, being larger when perceptual load decreased. However, this early modulatory effect in V1 was disrupted when participants transiently experienced increased state anxiety, resulting in a decreased C1 amplitude even though task load at fixation remained low. These results suggest that early bottom-up processing in V1 is not only influenced by the amount of attention resources available, but also by the current internal state of the participant. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Study of high density Escherichia coli fermentation for production of porcine somatotropin protein.

    PubMed

    Chang, L L; Hwang, L Y; Hwang, C F; Mou, D G

    1991-12-27

    Recombinant E. coli strains and culture conditions were studied for the fermentation expression of porcine somatotropin (PST) inclusion bodies under the control of a pL promoter. Our objective was to achieve high cell density together with a high level of recombinant protein expression. Improved fermentation conditions included oxygen enrichment, yeast extract (YE) effect, optimal specific growth to switch on gene expression, and feeding strategies. To maintain a low residual glucose concentration, a medium feed rate was controlled on a real-time basis by using cell density information estimated from on-line carbon dioxide monitoring of a fermentor's exhaust gas. The optimal specific growth rate required to initiate a temperature shift in our system was found to be around 0.2 hr-1. The cell density and PST expression level could reach 55 OD600 and 35%, respectively, after 16 hours of cultivation under optimal conditions by applying computer-controlled nutrient feed. In our recombinant host/vector system, the location of cl gene appears to affect gene expression under YE-supplemented and/or a high cell density culture condition. With cl gene placed on plasmid, our E. coli host no longer showed sensitivity toward YE in PST gene expression.

  18. Flow Regime Study in a High Density Circulating Fluidized Bed Riser with an Abrupt Exit

    SciTech Connect

    Mei, J.S.; Shadle, L.J.; Yue, P.C.; Monazam, E.R.

    2007-01-01

    Flow regime study was conducted in a 0.3 m diameter, 15.5 m height circulating fluidized bed (CFB) riser with an abrupt exit at the National Energy Technology Laboratory of the U.S. Department of Energy. Local particle velocities were measured at various radial positions and riser heights using an optical fiber probe. On-line measurement of solid circulating rate was continuously recorded by the Spiral. Glass beads of mean diameter 61 μm and particle density of 2,500 kg/m3 were used as bed material. The CFB riser was operated at various superficial gas velocities ranging from 3 to 7.6 m/s and solid mass flux from 20 to 550 kg/m2-s. At a constant riser gas velocity, transition from fast fluidization to dense suspension upflow (DSU) regime started at the bottom of the riser with increasing solid flux. Except at comparatively low riser gas velocity and solid flux, the apparent solid holdup at the top exit region was higher than the middle section of the riser. The solid fraction at this top region could be much higher than 7% under high riser gas velocity and solid mass flux. The local particle velocity showed downward flow near the wall at the top of the riser due to its abrupt exit. This abrupt geometry reflected the solids and, therefore, caused solid particles traveling downward along the wall. However, at location below, but near, the top of the riser the local particle velocities were observed flowing upward at the wall. Therefore, DSU was identified in the upper region of the riser with an abrupt exit while the fully developed region, lower in the riser, was still exhibiting core-annular flow structure. Our data were compared with the flow regime boundaries proposed by Kim et al. [1] for distinguishing the dilute pneumatic transport, fast fluidization, and DSU.

  19. Clusters of mu rhythm from EEG data: A comparative study between 61 and 19 channel datasets.

    PubMed

    Tacchino, G; Bianchi, A M

    2015-01-01

    The EEG mu rhythm is a sensorimotor oscillation which is desynchronized by voluntary movement execution. Independent Component Analysis (ICA) allows the decomposition of recorded scalp EEG data into temporally, functionally, and spatially independent source signals. Clustering techniques applied to independent sources resolved with ICA have been proven to be successful in the identification of clusters of sensorimotor mu rhythm across different subjects. The present work deals with the issue regarding the minimum number of data channels that is recommended to find reliable clusters of mu rhythm. Left and right mu clusters were identified from high-density EEG recordings (61 channels) belonging to a publicly available EEG database. A second dataset was created by selecting a small subset of the same high-density EEG recordings. Specifically, only the 19 channels belonging to the standard 10-20 International System were used for the identification of left and right mu clusters. Quantitative parameters computed from mu clusters obtained from both the 61-channel and the 19-channel datasets were statistically compared. The obtained results suggest that clusters of mu rhythm in sensorimotor areas can be reliably found from a lower number of EEG channels compared to high-density electrodes configuration.

  20. 'Time-shrinking perception' in the visual system: a psychophysical and high-density ERP study.

    PubMed

    Nagaike, Atsushi; Mitsudo, Takako; Nakajima, Yoshitaka; Ogata, Katsuya; Yamasaki, Takao; Goto, Yoshinobu; Tobimatsu, Shozo

    2016-11-01

    'Time-shrinking perception (TSP)' is a unique perceptual phenomenon in which the duration of two successive intervals (T1 and T2) marked by three auditory stimuli is perceived as equal even when they are physically different. This phenomenon provides a link between time and working memory; however, previous studies have mainly been performed on the auditory modality but not the visual modality. To clarify the neural mechanism of visual TSP, we performed a psychophysical experiment and recorded event-related potentials (ERPs) under different T1/T2 combinations. Three successive black/white sinusoidal gratings (30 ms duration) were presented to the participants. In the psychophysical experiment, either T1 or T2 was varied from 240 to 560 ms in 40-ms steps, while T2 or T1 was fixed at 400 ms. Participants judged whether T1 and T2 were equal or not by pressing a button. ERPs were recorded from 128 scalp electrodes, while T1 was varied from 240, 320, and 400 ms with the 400 ms T2 duration, and vice versa. Behavioral data showed asymmetrical assimilation: When -80 ms ≤ (T1 - T2) ≤ +120 ms, TSP was observed in the T1-varied condition. When -120 ms ≤ (T1 - T2) ≤ +80 ms, it was also observed in the T2-varied condition. These asymmetric time ranges in vision were different from those in the auditory modality. ERP data showed that contingent negative variation (CNV) appeared in the fronto-central region at around 300-500 ms during T2 presentation in the T1 < T2 condition. In the /240/400/ pattern, the CNV amplitude was decreased at around 350 ms. In contrast, P3 appeared at the parietal region about 450-650 ms after T2 in the T1 > T2 condition. In the /400/240/ pattern, P3 amplitude was greater than those of other temporal patterns. These neural responses corresponded to participants' perception that T1 and T2 were not equal. The neural responses in the fronto-central region were involved with endogenous temporal attention for

  1. Study of composite thin films for applications in high density data storage

    NASA Astrophysics Data System (ADS)

    Yuan, Hua

    Granular Co-alloy + oxide thin films are currently used as the magnetic recording layer of perpendicular media in hard disk drives. The microstructure of these films is composed mainly of fine (7--10 nm) magnetic grains physically surrounded by oxide phases, which produce magnetic isolation of the grains. As a result, the magnetic switching volume is maintained as small as the physical grain size. Consequently, ample number of magnetic switching units can be obtained in one recording bit, in other words, higher signal to noise ratios (SNR) can be achieved. Therefore, a good understanding and control of the microstructure of the films is very important for high areal density magnetic recording media. Interlayers and seedlayers play important roles in controlling the microstructure in terms of grain size, grain size distribution, oxide segregation and orientation dispersion of the crystallographic texture. Developing novel interlayers or seedlayers with smaller grain size is a key approach to produce smaller grain size in the recording layer. This study focuses on how to achieve smaller grain sizes in the recording layer through novel interlayer/seedlayer materials and processes. It also discusses the resulting microstructure in smaller-grain-size thin films. Metal + oxide (e.g. Ru + SiO2) composite thin films were chosen as interlayer and seedlayer materials due to their unique segregated microstructure. Such layers can be grown epitaxially on top of fcc metal seedlayers with good orientation. It can also provide an epitaxial growth template for the subsequent magnetic layer (recording layer). The metal and oxide phases in the composite thin films are immiscible. The final microstructure of the interlayer depends on factors, such as, sputtering pressure, oxide species, oxide volume fraction, thickness, alloy composition, temperature etc. Moreover, it has been found that the microstructure of the composite thin films is affected mostly by two important factors

  2. Comparative study of non-high density lipoproteins cholesterol level and lipid profile in pre-diabetic and diabetic patients.

    PubMed

    Banu, Shaheena; Jabir, Nasimudeen R; Manjunath, Nanjappa C; Firoz, C K; Kamal, Mohammad A; Khan, Mohammad S; Tabrez, Shams

    2014-04-01

    The present study compares the role and significance of non-high density lipoproteins (non-HDL) cholesterol level in pre-diabetic and diabetic patients. This study also compares non-HDL cholesterol level between males and females and with different age groups as well. An observational study was conducted among 3830 randomly selected individuals to envisage the association of non-HDL cholesterol and other lipid parameters with age, gender, and diabetic status. On the basis of health status, the subjects were classified as diabetic, pre-diabetic and normal. Fasting blood samples were collected and analyzed on Roche p-800 modular system. Total cholesterol, high density lipoproteins (HDL), low density lipoproteins (LDL) and fasting triglycerides were also measured. From the above mentioned parameters, the level of non-HDL cholesterol level was also calculated. Significant association was observed with non-HDL cholesterol level and all other studied lipid parameters (total cholesterol, HDL, LDL and triglycerides) compared with age and gender of the subjects studied. Moreover, the calculated non-HDL level, total cholesterol and triglycerides were found to be significantly co-related with diabetic status of the patients involved in the study. However, HDL and LDL values did not show any significant association with diabetic status of the patients. In this study, we found that age and gender of the studied subjects are associated with non-HDL cholesterol. Moreover, our data clearly indicates the positive association of non-HDL cholesterol level with pre-diabetic and diabetic status of the patients. Based on our study, we recommend estimation of non-HDL level in routine clinical practice to differentiate pre-diabetic and diabetic patients.

  3. The use of standardized infinity reference in EEG coherency studies.

    PubMed

    Marzetti, L; Nolte, G; Perrucci, M G; Romani, G L; Del Gratta, C

    2007-05-15

    The study of large scale interactions in the brain from EEG signals is a promising method for the identification of functional networks. However, the validity of a large scale parameter is limited by two factors: the use of a non-neutral reference and the artifactual self-interactions between the measured EEG signals introduced by volume conduction. In this paper, we propose an approach to study large scale EEG coherency in which these factors are eliminated. Artifactual self-interaction by volume conduction is eliminated by using the imaginary part of the complex coherency as a measure of interaction and the Reference Electrode Standardization Technique (REST) is used for the approximate standardization of the reference of scalp EEG recordings to a point at infinity that, being far from all possible neural sources, acts like a neutral virtual reference. The application of our approach to simulated and real EEG data shows that the detection of interaction, as opposed to artifacts due to reference and volume conduction, is a goal that can be achieved from the study of a large scale parameter.

  4. Sustained Attention in Real Classroom Settings: An EEG Study.

    PubMed

    Ko, Li-Wei; Komarov, Oleksii; Hairston, W David; Jung, Tzyy-Ping; Lin, Chin-Teng

    2017-01-01

    Sustained attention is a process that enables the maintenance of response persistence and continuous effort over extended periods of time. Performing attention-related tasks in real life involves the need to ignore a variety of distractions and inhibit attention shifts to irrelevant activities. This study investigates electroencephalography (EEG) spectral changes during a sustained attention task within a real classroom environment. Eighteen healthy students were instructed to recognize as fast as possible special visual targets that were displayed during regular university lectures. Sorting their EEG spectra with respect to response times, which indicated the level of visual alertness to randomly introduced visual stimuli, revealed significant changes in the brain oscillation patterns. The results of power-frequency analysis demonstrated a relationship between variations in the EEG spectral dynamics and impaired performance in the sustained attention task. Across subjects and sessions, prolongation of the response time was preceded by an increase in the delta and theta EEG powers over the occipital region, and decrease in the beta power over the occipital and temporal regions. Meanwhile, implementation of the complex attention task paradigm into a real-world classroom setting makes it possible to investigate specific mutual links between brain activities and factors that cause impaired behavioral performance, such as development and manifestation of classroom mental fatigue. The findings of the study set a basis for developing a system capable of estimating the level of visual attention during real classroom activities by monitoring changes in the EEG spectra.

  5. Sustained Attention in Real Classroom Settings: An EEG Study

    PubMed Central

    Ko, Li-Wei; Komarov, Oleksii; Hairston, W. David; Jung, Tzyy-Ping; Lin, Chin-Teng

    2017-01-01

    Sustained attention is a process that enables the maintenance of response persistence and continuous effort over extended periods of time. Performing attention-related tasks in real life involves the need to ignore a variety of distractions and inhibit attention shifts to irrelevant activities. This study investigates electroencephalography (EEG) spectral changes during a sustained attention task within a real classroom environment. Eighteen healthy students were instructed to recognize as fast as possible special visual targets that were displayed during regular university lectures. Sorting their EEG spectra with respect to response times, which indicated the level of visual alertness to randomly introduced visual stimuli, revealed significant changes in the brain oscillation patterns. The results of power-frequency analysis demonstrated a relationship between variations in the EEG spectral dynamics and impaired performance in the sustained attention task. Across subjects and sessions, prolongation of the response time was preceded by an increase in the delta and theta EEG powers over the occipital region, and decrease in the beta power over the occipital and temporal regions. Meanwhile, implementation of the complex attention task paradigm into a real-world classroom setting makes it possible to investigate specific mutual links between brain activities and factors that cause impaired behavioral performance, such as development and manifestation of classroom mental fatigue. The findings of the study set a basis for developing a system capable of estimating the level of visual attention during real classroom activities by monitoring changes in the EEG spectra. PMID:28824396

  6. High-density polyethylene facial implants show surface oxidation in SEM and EDX examination: a pilot study.

    PubMed

    Draenert, G F; Doeblinger, M; Draenert, M; Gosau, M

    2009-05-01

    Previous histopathological studies on explanted Medpor high-density polyethylene (HDPE) facial implants indicated signs of material destruction and claimed to observe phagocytized HDPE particles within the tissue samples beside the usual type IV reaction with severe fibrosis. We examined new and explanted Medpor material with scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The implant surface of three patient-derived specimens showed significantly higher oxygenation in EDX analysis and morphological changes in SEM compared to the new unused material directly after opening of the package and after 1 year of exposure to air. Our preliminary findings indicate a possible oxidative biocorrosion in HDPE surgical implants. Further studies should confirm these pilot project results.

  7. Relationship between Job Stress and Hypo-high-density Lipoproteinemia of Chinese Workers in Shanghai: The Rosai Karoshi Study

    PubMed Central

    Muratsubaki, Tomohiko; Hattori, Tomomi; Li, Jue; Fukudo, Shin; Munakata, Masanori

    2016-01-01

    Background: Karoshi, or death due to overwork, has now become a serious social problem in China. Worsening of cardiovascular risks by stress might initiate karoshi. Many studies have examined the relationship between job stress and obesity, hypertension, and type 2 diabetes mellitus, but less evidence exists for dyslipidemia like hypo-high-density lipoproteinemia (hypo-HDL). The aim of this study was to investigate the relationship between job stress and hypo-HDL of Chinese workers in Shanghai. Methods: We studied 2219 Chinese workers in Shanghai, who participated in the Japan-China cooperative study for the prevention of karoshi. A questionnaire was administered to examine the lifestyle characteristics, job category, weekly working hours, and job stress. Job demand and job control were quantified using the National Institute for Occupational Safety and Health questionnaire. Modified job strain measure was defined by the combination of low job control and high demand. Hypo-HDL was defined as plasma high-density lipoprotein cholesterol concentration of <1.04 mmol/L (40 mg/dl). Multivariate logistic regression analysis was performed for hypo-HDL as a dependent variable. Results: Modified job strain was not related to hypo-HDL either in men or women. In men, multivariate adjusted odds ratio (OR) for having hypo-HDL was significantly higher in the lowest job control tertile compared with the highest job control tertile (OR = 1.39, 95% confidence interval [CI] 1.03–1.87, P = 0.034). In the same model, a similar trend was observed for women, but it did not reach a statistically significant level (OR = 1.51, 95% CI, 0.88–2.56, P = 0.132). Conclusion: A low level of job control but not modified job strain was significantly related to higher prevalence of hypo-HDL of Chinese workers in Shanghai. PMID:27748331

  8. Relationship between Job Stress and Hypo-high-density Lipoproteinemia of Chinese Workers in Shanghai: The Rosai Karoshi Study.

    PubMed

    Muratsubaki, Tomohiko; Hattori, Tomomi; Li, Jue; Fukudo, Shin; Munakata, Masanori

    2016-10-20

    Karoshi, or death due to overwork, has now become a serious social problem in China. Worsening of cardiovascular risks by stress might initiate karoshi. Many studies have examined the relationship between job stress and obesity, hypertension, and type 2 diabetes mellitus, but less evidence exists for dyslipidemia like hypo-high-density lipoproteinemia (hypo-HDL). The aim of this study was to investigate the relationship between job stress and hypo-HDL of Chinese workers in Shanghai. We studied 2219 Chinese workers in Shanghai, who participated in the Japan-China cooperative study for the prevention of karoshi. A questionnaire was administered to examine the lifestyle characteristics, job category, weekly working hours, and job stress. Job demand and job control were quantified using the National Institute for Occupational Safety and Health questionnaire. Modified job strain measure was defined by the combination of low job control and high demand. Hypo-HDL was defined as plasma high-density lipoprotein cholesterol concentration of <1.04 mmol/L (40 mg/dl). Multivariate logistic regression analysis was performed for hypo-HDL as a dependent variable. Modified job strain was not related to hypo-HDL either in men or women. In men, multivariate adjusted odds ratio (OR) for having hypo-HDL was significantly higher in the lowest job control tertile compared with the highest job control tertile (OR = 1.39, 95% confidence interval [CI] 1.03-1.87, P = 0.034). In the same model, a similar trend was observed for women, but it did not reach a statistically significant level (OR = 1.51, 95% CI, 0.88-2.56, P = 0.132). A low level of job control but not modified job strain was significantly related to higher prevalence of hypo-HDL of Chinese workers in Shanghai.

  9. Influence of total cholesterol, high density lipoprotein cholesterol, and triglycerides on risk of cerebrovascular disease: the Copenhagen City Heart Study.

    PubMed Central

    Lindenstrøm, E.; Boysen, G.; Nyboe, J.

    1994-01-01

    OBJECTIVE--To estimate the influence of plasma total cholesterol, high density lipoprotein cholesterol, and triglycerides on risk of cerebrovascular disease. DESIGN--The Copenhagen City Heart Study is a prospective observational survey with two cardiovascular examinations at five year intervals. Non-fasting plasma lipids were measured in participants once at each examination, along with other variables. The Cox regression model was used to establish the effect of the factors recorded on cerebrovascular events of mostly, but not exclusively, ischaemic origin. SUBJECTS--19,698 women and men at least 20 years old, randomly selected after age stratification from an area of central Copenhagen. MAIN OUTCOME MEASURES--Initial cases of stroke and transient ischaemic attack recorded from hospital records and death certificates from 1976 through 1988. RESULTS--660 non-haemorrhagic and 33 haemorrhagic events were recorded. Total cholesterol was positively associated with risk of non-haemorrhagic events, but only for levels > 8 mmol/l, corresponding to the upper 5% of the distribution in the study population. For lower plasma cholesterol values the relative risk remained nearly constant. Plasma triglyceride concentration was significantly, positively associated with risk of non-haemorrhagic events. The relative risk corresponding to an increase of 1 mmol/l was 1.12 (95% confidence interval 1.07 to 1.16). There was a negative, log linear association between high density lipoprotein cholesterol and risk of non-haemorrhagic events (0.53 (0.34 to 0.83)). There was no indication that the effects of plasma lipids were different in women and men. CONCLUSIONS--The pattern of the association between plasma cholesterol and risk of ischaemic cerebrovascular disease was not log linear, and the increased risk was confined to the upper 5% of the cholesterol distribution. Further studies should concentrate on the association between plasma cholesterol and verified haemorrhagic stroke. PMID

  10. Amplitude Integrated Electroencephalography Compared With Conventional Video EEG for Neonatal Seizure Detection: A Diagnostic Accuracy Study.

    PubMed

    Rakshasbhuvankar, Abhijeet; Rao, Shripada; Palumbo, Linda; Ghosh, Soumya; Nagarajan, Lakshmi

    2017-08-01

    This diagnostic accuracy study compared the accuracy of seizure detection by amplitude-integrated electroencephalography with the criterion standard conventional video EEG in term and near-term infants at risk of seizures. Simultaneous recording of amplitude-integrated EEG (2-channel amplitude-integrated EEG with raw trace) and video EEG was done for 24 hours for each infant. Amplitude-integrated EEG was interpreted by a neonatologist; video EEG was interpreted by a neurologist independently. Thirty-five infants were included in the analysis. In the 7 infants with seizures on video EEG, there were 169 seizure episodes on video EEG, of which only 57 were identified by amplitude-integrated EEG. Amplitude-integrated EEG had a sensitivity of 33.7% for individual seizure detection. Amplitude-integrated EEG had an 86% sensitivity for detection of babies with seizures; however, it was nonspecific, in that 50% of infants with seizures detected by amplitude-integrated EEG did not have true seizures by video EEG. In conclusion, our study suggests that amplitude-integrated EEG is a poor screening tool for neonatal seizures.

  11. Epileptic EEG: a comprehensive study of nonlinear behavior.

    PubMed

    Daneshyari, Moayed; Kamkar, L Lily; Daneshyari, Matin

    2010-01-01

    In this study, the nonlinear properties of the electroencephalograph (EEG) signals are investigated by comparing two sets of EEG, one set for epileptic and another set for healthy brain activities. Adopting measures of nonlinear theory such as Lyapunov exponent, correlation dimension, Hurst exponent, fractal dimension, and Kolmogorov entropy, the chaotic behavior of these two sets is quantitatively computed. The statistics for the two groups of all measures demonstrate the differences between the normal healthy group and epileptic one. The statistical results along with phase-space diagram verify that brain under epileptic seizures possess limited trajectory in the state space than in healthy normal state, consequently behaves less chaotically compared to normal condition.

  12. [Correlation between EEG and neuroimaging].

    PubMed

    Tobimatsu, Shozo

    2012-01-01

    The present state of knowledge of physiological mechanisms underlying nonepileptiform EEG abnormalities is reviewed to clarify the correlation between EEG and neuroimaging. Focal and widespread slow waves, background abnormalities, and bursts of rhythmic slow activity are discussed. EEG phenomena were correlated with lesion size, location, type (white matter vs. gray matter, high density vs. low density), and mass effect. Clinical and experimental accumulated over the past five decades suggest that polymorphic slow activity is generated in cerebral cortex by layers of pyramidal cells and is probably due to partial deafferentation from subcortical areas. Unilateral background activity changes are probably thalamic dysfunction, and bilateral paroxysmal slow activity is due to abnormal thalamocortical circuits combined with cortical pathology. Paroxysmal discharges indicate the presence of epilepsy with possible brain lesion(s). The EEG is a functional test and provides us complementary information to neuroimaging studies.

  13. Developmental trajectories of EEG sleep slow wave activity as a marker for motor skill development during adolescence: a pilot study.

    PubMed

    Lustenberger, Caroline; Mouthon, Anne-Laure; Tesler, Noemi; Kurth, Salome; Ringli, Maya; Buchmann, Andreas; Jenni, Oskar G; Huber, Reto

    2017-01-01

    Reliable markers for brain maturation are important to identify neural deviations that eventually predict the development of mental illnesses. Recent studies have proposed topographical EEG-derived slow wave activity (SWA) during NREM sleep as a mirror of cortical development. However, studies about the longitudinal stability as well as the relationship with behavioral skills are needed before SWA topography may be considered such a reliable marker. We examined six subjects longitudinally (over 5.1 years) using high-density EEG and a visuomotor learning task. All subjects showed a steady increase of SWA at a frontal electrode and a decrease in central electrodes. Despite these large changes in EEG power, SWA topography was relatively stable within each subject during development indicating individual trait-like characteristics. Moreover, the SWA changes in the central cluster were related to the development of specific visuomotor skills. Taken together with the previous work in this domain, our results suggest that EEG sleep SWA represents a marker for motor skill development and further supports the idea that SWA mirrors cortical development during childhood and adolescence. © 2016 Wiley Periodicals, Inc.

  14. Epileptic networks studied with EEG-fMRI.

    PubMed

    Gotman, Jean

    2008-01-01

    It is not easy to determine the location of the cerebral generators and the other brain regions that may be involved at the time of an epileptic spike seen in the scalp EEG. The possibility to combine EEG recording with functional MRI scanning (fMRI) opens the opportunity to uncover the regions of the brain showing changes in metabolism and blood flow in response to epileptic spikes seen in the EEG. These regions are presumably involved in the abnormal neuronal activity at the origin of epileptic discharges. This paper reviews the methodology involved in performing such studies, including the special techniques required for recording the EEG inside the scanner and the statistical issues in analyzing the fMRI signal. We then discuss the results obtained in patients with different types of focal epileptic disorders and in patients with primary generalized epilepsy. The results in general indicate that interictal epileptic discharges may affect brain areas well beyond the presumed region in which they are generated. The noninvasive nature of this method opens new horizons in the investigation of brain regions involved and affected by epileptic discharges.

  15. Building an EEG-fMRI Multi-Modal Brain Graph: A Concurrent EEG-fMRI Study.

    PubMed

    Yu, Qingbao; Wu, Lei; Bridwell, David A; Erhardt, Erik B; Du, Yuhui; He, Hao; Chen, Jiayu; Liu, Peng; Sui, Jing; Pearlson, Godfrey; Calhoun, Vince D

    2016-01-01

    The topological architecture of brain connectivity has been well-characterized by graph theory based analysis. However, previous studies have primarily built brain graphs based on a single modality of brain imaging data. Here we develop a framework to construct multi-modal brain graphs using concurrent EEG-fMRI data which are simultaneously collected during eyes open (EO) and eyes closed (EC) resting states. FMRI data are decomposed into independent components with associated time courses by group independent component analysis (ICA). EEG time series are segmented, and then spectral power time courses are computed and averaged within 5 frequency bands (delta; theta; alpha; beta; low gamma). EEG-fMRI brain graphs, with EEG electrodes and fMRI brain components serving as nodes, are built by computing correlations within and between fMRI ICA time courses and EEG spectral power time courses. Dynamic EEG-fMRI graphs are built using a sliding window method, versus static ones treating the entire time course as stationary. In global level, static graph measures and properties of dynamic graph measures are different across frequency bands and are mainly showing higher values in eyes closed than eyes open. Nodal level graph measures of a few brain components are also showing higher values during eyes closed in specific frequency bands. Overall, these findings incorporate fMRI spatial localization and EEG frequency information which could not be obtained by examining only one modality. This work provides a new approach to examine EEG-fMRI associations within a graph theoretic framework with potential application to many topics.

  16. Building an EEG-fMRI Multi-Modal Brain Graph: A Concurrent EEG-fMRI Study

    PubMed Central

    Yu, Qingbao; Wu, Lei; Bridwell, David A.; Erhardt, Erik B.; Du, Yuhui; He, Hao; Chen, Jiayu; Liu, Peng; Sui, Jing; Pearlson, Godfrey; Calhoun, Vince D.

    2016-01-01

    The topological architecture of brain connectivity has been well-characterized by graph theory based analysis. However, previous studies have primarily built brain graphs based on a single modality of brain imaging data. Here we develop a framework to construct multi-modal brain graphs using concurrent EEG-fMRI data which are simultaneously collected during eyes open (EO) and eyes closed (EC) resting states. FMRI data are decomposed into independent components with associated time courses by group independent component analysis (ICA). EEG time series are segmented, and then spectral power time courses are computed and averaged within 5 frequency bands (delta; theta; alpha; beta; low gamma). EEG-fMRI brain graphs, with EEG electrodes and fMRI brain components serving as nodes, are built by computing correlations within and between fMRI ICA time courses and EEG spectral power time courses. Dynamic EEG-fMRI graphs are built using a sliding window method, versus static ones treating the entire time course as stationary. In global level, static graph measures and properties of dynamic graph measures are different across frequency bands and are mainly showing higher values in eyes closed than eyes open. Nodal level graph measures of a few brain components are also showing higher values during eyes closed in specific frequency bands. Overall, these findings incorporate fMRI spatial localization and EEG frequency information which could not be obtained by examining only one modality. This work provides a new approach to examine EEG-fMRI associations within a graph theoretic framework with potential application to many topics. PMID:27733821

  17. The development of audiovisual multisensory integration across childhood and early adolescence: a high-density electrical mapping study.

    PubMed

    Brandwein, Alice B; Foxe, John J; Russo, Natalie N; Altschuler, Ted S; Gomes, Hilary; Molholm, Sophie

    2011-05-01

    The integration of multisensory information is essential to forming meaningful representations of the environment. Adults benefit from related multisensory stimuli but the extent to which the ability to optimally integrate multisensory inputs for functional purposes is present in children has not been extensively examined. Using a cross-sectional approach, high-density electrical mapping of event-related potentials (ERPs) was combined with behavioral measures to characterize neurodevelopmental changes in basic audiovisual (AV) integration from middle childhood through early adulthood. The data indicated a gradual fine-tuning of multisensory facilitation of performance on an AV simple reaction time task (as indexed by race model violation), which reaches mature levels by about 14 years of age. They also revealed a systematic relationship between age and the brain processes underlying multisensory integration (MSI) in the time frame of the auditory N1 ERP component (∼ 120 ms). A significant positive correlation between behavioral and neurophysiological measures of MSI suggested that the underlying brain processes contributed to the fine-tuning of multisensory facilitation of behavior that was observed over middle childhood. These findings are consistent with protracted plasticity in a dynamic system and provide a starting point from which future studies can begin to examine the developmental course of multisensory processing in clinical populations.

  18. An analytical study of a novel and new failure mechanism observed in a high density CMOS ULSI device

    SciTech Connect

    Pyle, R.E.; Kaushik, V.; Laberge, P.; Morris, S.; Martin, L.; Prack, E.; Hance, R.; Bridwell, J.

    1995-12-31

    A Reliability Engineering group recently observed failures during a highly accelerated moisture stress test on high density CMOS ULSI devices. Failure Analysis traced the electrical failures to the column fuse area. It appeared from FIB (Focused Ion Beam)/SEM (Scanning Electron Microscopy) cross sections that corrosion of the third polycide tungsten silicide layer adjacent to some of the blown fuses had occurred. This had resulted in column failures in the redundancy circuits. To support the Product Group a comprehensive analytical study by the MOS Analytical Laboratories was invoked. The root cause of the observed failures was determined by AES analyses to be due to excessive oxygen within the tungsten silicide layer incorporated during wafer processing. It is believed that this excessive oxygen reacts with components of the tungsten silicide film and thereby destabilizes the film through excessive stress making it much more susceptible to chemical or electrochemical decomposition as observed. This paper will focus on the results of the comprehensive analytical investigation leading to this conclusion and will postulate a mechanism for this new and novel failure mechanism.

  19. Segregation analysis of low levels of high-density lipoprotein cholesterol in the collaborative Lipid Research Clinics Program Family Study.

    PubMed Central

    Bucher, K D; Kaplan, E B; Namboodiri, K K; Glueck, C J; Laskarzewski, P; Rifkind, B M

    1987-01-01

    Complex segregation analysis with the unified mixed model in white families from nine lipid research clinics was carried out to delineate the mode of familial transmission of plasma high-density-lipoprotein cholesterol (HDL-C). Three groups of families from the collaborative Lipid Research Clinics Program Family Study were assessed: 1,146 selected at random, 483 obtained through hypercholesterolemic probands, and 177 selected from the random sample because a number had low HDL-C, the sample sizes being 4,279, 1,807 and 735, respectively. The data were first transformed and adjusted for effects of covariates. Analyses were performed within clinic and selection strata and also pooled across clinics within strata. The results were consistent across strata and identified two major HDL-C clusters with means separated by approximately 3 SD. There was significant evidence of transmission of a major factor for low HDL-C, but transmission did not conform to Mendelian segregation expectations. There was also evidence of significant multifactorial transmission. Since low HDL-C levels are a major independent risk factor for coronary heart disease, the association of a major factor with familial aggregation of low HDL-C emphasizes the importance of detailed within-family sampling for low HDL-C after identifying a proband whose predominant dyslipoproteinemia is low HDL-C. PMID:3591798

  20. Genome-wide association studies identified novel loci for non-high-density lipoprotein cholesterol and its postprandial lipemic response.

    PubMed

    An, Ping; Straka, Robert J; Pollin, Toni I; Feitosa, Mary F; Wojczynski, Mary K; Daw, E Warwick; O'Connell, Jeffrey R; Gibson, Quince; Ryan, Kathleen A; Hopkins, Paul N; Tsai, Michael Y; Lai, Chao-Qiang; Province, Michael A; Ordovas, Jose M; Shuldiner, Alan R; Arnett, Donna K; Borecki, Ingrid B

    2014-07-01

    Non-high-density lipoprotein cholesterol(NHDL) is an independent and superior predictor of CVD risk as compared to low-density lipoprotein alone. It represents a spectrum of atherogenic lipid fractions with possibly a distinct genomic signature. We performed genome-wide association studies (GWAS) to identify loci influencing baseline NHDL and its postprandial lipemic (PPL) response. We carried out GWAS in 4,241 participants of European descent. Our discovery cohort included 928 subjects from the Genetics of Lipid-Lowering Drugs and Diet Network Study. Our replication cohorts included 3,313 subjects from the Heredity and Phenotype Intervention Heart Study and Family Heart Study. A linear mixed model using the kinship matrix was used for association tests. The best association signal was found in a tri-genic region at RHOQ-PIGF-CRIPT for baseline NHDL (lead SNP rs6544903, discovery p = 7e-7, MAF = 2 %; validation p = 6e-4 at 0.1 kb upstream neighboring SNP rs3768725, and 5e-4 at 0.7 kb downstream neighboring SNP rs6733143, MAF = 10 %). The lead and neighboring SNPs were not perfect surrogate proxies to each other (D' = 1, r (2) = 0.003) but they seemed to be partially dependent (likelihood ration test p = 0.04). Other suggestive loci (discovery p < 1e-6) included LOC100419812 and LOC100288337 for baseline NHDL, and LOC100420502 and CDH13 for NHDL PPL response that were not replicated (p > 0.01). The current and first GWAS of NHDL yielded an interesting common variant in RHOQ-PIGF-CRIPT influencing baseline NHDL levels. Another common variant in CDH13 for NHDL response to dietary high-fat intake challenge was also suggested. Further validations for both loci from large independent studies, especially interventional studies, are warranted.

  1. Genome-wide association studies identified novel loci for non-high-density lipoprotein cholesterol and its postprandial lipemic response

    PubMed Central

    An, Ping; Straka, Robert J.; Pollin, Toni I.; Feitosa, Mary F.; Wojczynski, Mary K.; Daw, E. Warwick; O'Connell, Jeffrey R.; Gibson, Quince; Ryan, Kathleen A.; Hopkins, Paul N.; Tsai, Michael Y.; Lai, Chao-Qiang; Province, Michael A.; Ordovas, Jose M.; Shuldiner, Alan R; Arnett, Donna K.; Borecki, Ingrid B.

    2014-01-01

    Non-high-density lipoprotein cholesterol (NHDL) is an independent and superior predictor of CVD risk as compared to LDL alone. It represents a spectrum of atherogenic lipid fractions with possibly a distinct genomic signature. We performed genome-wide association studies (GWAS) to identify loci influencing baseline NHDL and its postprandial lipemic (PPL) response. We carried out GWAS in 4,241 participants of European descent. Our discovery cohort included 928 subjects from the Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) Study. Our replication cohorts included 3,313 subjects from the Heredity and Phenotype Intervention (HAPI) Heart Study and Family Heart Study (FamHS). A linear mixed model using the kinship matrix was used for association tests. The best association signal was found in a tri-genic region at RHOQ-PIGF-CRIPT for baseline NHDL (lead SNP rs6544903, discovery p = 7e-7, MAF = 2%; validation p = 6e-4 at 0.1 kb upstream neighboring SNP rs3768725, and 5e-4 at 0.7 kb downstream neighboring SNP rs6733143, MAF = 10%). The lead and neighboring SNPs were not perfect surrogate proxies to each other (D′ = 1, r2 = 0.003) but they seemed to be partially dependent (likelihood ration test p = 0.04). Other suggestive loci (discovery p < 1e-6) included LOC100419812 and LOC100288337 for baseline NHDL, and LOC100420502 and CDH13 for NHDL PPL response that were not replicated (p > 0.01). The current and first GWAS of NHDL yielded an interesting common variant in RHOQ-PIGF-CRIPT influencing baseline NHDL levels. Another common variant in CDH13 for NHDL response to dietary high fat intake challenge was also suggested. Further validations for both loci from large independent studies, especially interventional studies, are warranted. PMID:24604477

  2. Pharmaco-EEG Studies in Animals: A History-Based Introduction to Contemporary Translational Applications.

    PubMed

    Drinkenburg, Wilhelmus H I M; Ahnaou, Abdallah; Ruigt, Gé S F

    2015-01-01

    Current research on the effects of pharmacological agents on human neurophysiology finds its roots in animal research, which is also reflected in contemporary animal pharmaco-electroencephalography (p-EEG) applications. The contributions, present value and translational appreciation of animal p-EEG-based applications are strongly interlinked with progress in recording and neuroscience analysis methodology. After the pioneering years in the late 19th and early 20th century, animal p-EEG research flourished in the pharmaceutical industry in the early 1980s. However, around the turn of the millennium the emergence of structurally and functionally revealing imaging techniques and the increasing application of molecular biology caused a temporary reduction in the use of EEG as a window into the brain for the prediction of drug efficacy. Today, animal p-EEG is applied again for its biomarker potential - extensive databases of p-EEG and polysomnography studies in rats and mice hold EEG signatures of a broad collection of psychoactive reference and test compounds. A multitude of functional EEG measures has been investigated, ranging from simple spectral power and sleep-wake parameters to advanced neuronal connectivity and plasticity parameters. Compared to clinical p-EEG studies, where the level of vigilance can be well controlled, changes in sleep-waking behaviour are generally a prominent confounding variable in animal p-EEG studies and need to be dealt with. Contributions of rodent pharmaco-sleep EEG research are outlined to illustrate the value and limitations of such preclinical p-EEG data for pharmacodynamic and chronopharmacological drug profiling. Contemporary applications of p-EEG and pharmaco-sleep EEG recordings in animals provide a common and relatively inexpensive window into the functional brain early in the preclinical and clinical development of psychoactive drugs in comparison to other brain imaging techniques. They provide information on the impact of

  3. Inter-machine validation study of neoclassical transport modelling in medium- to high-density stellarator-heliotron plasmas

    NASA Astrophysics Data System (ADS)

    Dinklage, A.; Yokoyama, M.; Tanaka, K.; Velasco, J. L.; López-Bruna, D.; Beidler, C. D.; Satake, S.; Ascasíbar, E.; Arévalo, J.; Baldzuhn, J.; Feng, Y.; Gates, D.; Geiger, J.; Ida, K.; Isaev, M.; Jakubowski, M.; López-Fraguas, A.; Maaßberg, H.; Miyazawa, J.; Morisaki, T.; Murakami, S.; Pablant, N.; Kobayashi, S.; Seki, R.; Suzuki, C.; Suzuki, Y.; Turkin, Yu.; Wakasa, A.; Wolf, R.; Yamada, H.; Yoshinuma, M.; LHD Exp. Group; TJ-II Team; W7-AS Team

    2013-06-01

    A comparative study of energy transport for medium- to high-density discharges in the stellarator-heliotrons TJ-II, W7-AS and LHD is carried out. The specific discharge parameters are chosen to apply a recently concluded benchmarking study of neoclassical (NC) transport coefficients (Beidler et al 2011 Nucl. Fusion 51 076001) to perform this validation study. In contrast to previous experiments at low densities for which electron transport was predominant (Yokoyama et al 2007 Nucl. Fusion 47 1213), the current discharges also exhibit significant ion energy transport. As it affects the energy transport in 3D devices, the ambipolar radial electric field is addressed as well. For the discharges described, ion-root conditions, i.e. a small negative radial electric field were found. The energy transport in the peripheral region cannot be explained by NC theory. Within a ‘core region’(r/a < 1/2 ∼ 2/3), the predicted NC energy fluxes comply with experimental findings for W7-AS. For TJ-II, compliance in the core region is found for the particle transport and the electron energy transport. For the specific LHD discharges, the core energy transport complied with NC theory except for the electron energy transport in the inward-shifted magnetic configuration. The NC radial electric field tends to agree with experimental results for all devices but is measured to be more negative in the core of both LHD and TJ-II. As a general observation, the energy confinement time approaches the gyro-Bohm-type confinement scaling ISS04 (Yamada et al 2005 Nucl. Fusion 45 1684). This work is carried out within the International Stellarator-Heliotron Profile Database (www.ipp.mpg.de/ISS and http://ishpdb.nifs.ac.jp/index.html).

  4. Association of high-density lipoprotein subclasses and incident coronary heart disease: The Jackson Heart and Framingham Offspring Cohort Studies

    PubMed Central

    Joshi, Parag H; Toth, Peter P; Lirette, Seth T; Griswold, Michael E; Massaro, Joseph M; Martin, Seth S; Blaha, Michael J; Kulkarni, Krishnaji R; Khokhar, Arif A; Correa, Adolfo; D’Agustino, Ralph B; Jones, Steven R

    2015-01-01

    Aims We aimed to clarify the associations of high-density lipoprotein cholesterol (HDL-C) subclasses with incident coronary heart disease (CHD) in two large primary prevention cohorts. Methods We measured cholesterol at baseline from the two major HDL subfractions (larger, more buoyant HDL2 and smaller, denser HDL3) separated by density gradient ultracentrifugation in 4114 (mean age 53.8 years; 64% female) African American participants from the Jackson Heart Study and 818 (mean age 57.3 years, 52% female) predominantly Caucasian participants from the Framingham Offspring Cohort Study. Multivariable adjusted hazard ratios (HRs) for HDL-C and its subclasses were derived from Cox proportional hazards regression models to estimate associations with incident CHD events including myocardial infarction, CHD death, and revascularization. Analyses were performed for each cohort separately and as a combined population. Results In models adjusted for cardiovascular risk factors for the combined population, HDL3-C (HR 0.76 per SD increase; 95% confidence interval (CI), 0.62–0.94; p = 0.01), rather than HDL2-C (HR 0.88 per SD; 95% CI, 0.72–1.09; p = 0.24) drove the inverse association of HDL-C (HR 0.79 per SD; 95% CI, 0.64–0.98; p = 0.03) with CHD. Similar associations were seen in multivariable analyses within each cohort including after adjusting for apolipoprotein A1 in the Jackson Heart Study. Conclusion Smaller, denser HDL3-C levels are primarily responsible for the inverse association between HDL-C and incident CHD in this diverse group of primary prevention subjects. These findings have important implications ranging from considerations of HDL biology to interpretations of clinical trials utilizing HDL-C therapeutics. PMID:25062744

  5. Physical inactivity interacts with an endothelial lipase polymorphism to modulate high density lipoprotein cholesterol in the GOLDN study

    USDA-ARS?s Scientific Manuscript database

    BACKGROUND: Plasma high density lipoprotein (HDL) cholesterol (HDL-C) concentration is highly heritable but is also modifiable by environmental factors including physical activity. HDL-C response to exercise varies among individuals, and this variability may be associated with genetic polymorphism...

  6. Structure development during isothermal crystallisation of high-density polyethylene: Synchrotron small-angle X-ray scattering study

    NASA Astrophysics Data System (ADS)

    Ślusarczyk, Czesław

    2013-12-01

    Isothermal melt crystallisation in high-density polyethylene (HDPE) was studied using the time-resolved SAXS method with synchrotron radiation over a wide range of crystallisation temperatures. The SAXS profile was analysed by an interface distribution function, g1(r), which is a superposition of three contributions associated with the size distributions of crystalline (LC) and amorphous (LA) layers and a distribution of long period (LP). The morphological parameters extracted from the g1(r) functions show that the lamellar thickness increases with time, obeying a logarithmic time dependence. The time evolution of LC observed for the sample crystallised at 122 °C leads to the conclusion that crystallisation proceeds according to the mechanism of thickening growth. For samples crystallised at lower temperatures (116 °C and 118 °C), the lamellar thickening mechanism has been observed. The rate of lamellar thickening in these cases is much lower than that at 122 °C. At 40 °C, thickening of the crystalline layer does not occur. The interface distribution functions were deconvoluted, and the relative standard deviation σC/LC obtained in this way is an additional parameter that is varied during crystallisation and can be used for analysis of this process. Time-dependent changes in the σC/LC at large supercooling (TC=40 °C) indicates that LC presents a broad distribution in which the relative standard deviation increases with time. At lower supercooling (TC=122 °C), LC shows a much sharper distribution. In this case, the relative standard deviation decreases with time.

  7. Relationship between low levels of high-density lipoprotein cholesterol and dementia in the elderly. The InChianti study.

    PubMed

    Zuliani, G; Cavalieri, M; Galvani, M; Volpato, S; Cherubini, A; Bandinelli, S; Corsi, A M; Lauretani, F; Guralnik, J M; Fellin, R; Ferrucci, L

    2010-05-01

    To evaluate the association between plasma lipid fractions and the prevalence of dementia in a large sample of Italian older individuals. A total of 1051 older community-dwelling individuals (age >/=65 years), enrolled in the InChianti study, were included. Diagnosis of dementia was established at baseline and at the 3-year follow-up using Diagnostic and Statistical Manual of Mental Disorder (Fourth Edition) criteria. Plasma lipids were measured by standardized methods at baseline and after 3 years. At baseline, 61 individuals (5.8%) were affected by dementia. Demented individuals showed significantly lower total cholesterol (TC), nonhigh-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C) levels compared with controls; no differences were found in triglycerides (TG) and lipoprotein (a) levels. Of the 819 subjects reevaluated at the 3-year follow-up, 81 (9.9%) received a new diagnosis of dementia. Again, demented subjects were characterized by significantly lower TC, non-HDL-C, and HDL-C levels compared with controls, thus confirming the baseline findings. At multivariate logistic regression analysis, HDL-C levels (odds ratio: 0.96, 95% confidence interval: 0.93-0.99), but not TG and non-HDL-C, were associated with dementia independent of important confounders including age, gender, apo E phenotype, stroke, weight loss, interleukin 6 levels, and ankle-brachial index. Among community-dwelling older people, individuals affected by dementia showed significantly lower TC, non-HDL-C, and HDL-C levels; however, at multivariate analysis, only HDL-C was associated with dementia. Our results suggest the existence of an independent relationship between dementia and low HDL-C levels.

  8. Relationship Between Low Levels of High-Density Lipoprotein Cholesterol and Dementia in the Elderly. The InChianti Study

    PubMed Central

    Cavalieri, M.; Galvani, M.; Volpato, S.; Cherubini, A.; Bandinelli, S.; Corsi, A. M.; Lauretani, F.; Guralnik, J. M.; Fellin, R.; Ferrucci, L.

    2010-01-01

    Background. To evaluate the association between plasma lipid fractions and the prevalence of dementia in a large sample of Italian older individuals. Methods. A total of 1051 older community-dwelling individuals (age ≥65 years), enrolled in the InChianti study, were included. Diagnosis of dementia was established at baseline and at the 3-year follow-up using Diagnostic and Statistical Manual of Mental Disorder (Fourth Edition) criteria. Plasma lipids were measured by standardized methods at baseline and after 3 years. Results. At baseline, 61 individuals (5.8%) were affected by dementia. Demented individuals showed significantly lower total cholesterol (TC), nonhigh–density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C) levels compared with controls; no differences were found in triglycerides (TG) and lipoprotein (a) levels. Of the 819 subjects reevaluated at the 3-year follow-up, 81 (9.9%) received a new diagnosis of dementia. Again, demented subjects were characterized by significantly lower TC, non-HDL-C, and HDL-C levels compared with controls, thus confirming the baseline findings. At multivariate logistic regression analysis, HDL-C levels (odds ratio: 0.96, 95% confidence interval: 0.93–0.99), but not TG and non-HDL-C, were associated with dementia independent of important confounders including age, gender, apo E phenotype, stroke, weight loss, interleukin 6 levels, and ankle–brachial index. Conclusions. Among community-dwelling older people, individuals affected by dementia showed significantly lower TC, non-HDL-C, and HDL-C levels; however, at multivariate analysis, only HDL-C was associated with dementia. Our results suggest the existence of an independent relationship between dementia and low HDL-C levels. PMID:20299544

  9. Multisensory processing of naturalistic objects in motion: a high-density electrical mapping and source estimation study.

    PubMed

    Senkowski, Daniel; Saint-Amour, Dave; Kelly, Simon P; Foxe, John J

    2007-07-01

    In everyday life, we continuously and effortlessly integrate the multiple sensory inputs from objects in motion. For instance, the sound and the visual percept of vehicles in traffic provide us with complementary information about the location and motion of vehicles. Here, we used high-density electrical mapping and local auto-regressive average (LAURA) source estimation to study the integration of multisensory objects in motion as reflected in event-related potentials (ERPs). A randomized stream of naturalistic multisensory-audiovisual (AV), unisensory-auditory (A), and unisensory-visual (V) "splash" clips (i.e., a drop falling and hitting a water surface) was presented among non-naturalistic abstract motion stimuli. The visual clip onset preceded the "splash" onset by 100 ms for multisensory stimuli. For naturalistic objects early multisensory integration effects beginning 120-140 ms after sound onset were observed over posterior scalp, with distributed sources localized to occipital cortex, temporal lobule, insular, and medial frontal gyrus (MFG). These effects, together with longer latency interactions (210-250 and 300-350 ms) found in a widespread network of occipital, temporal, and frontal areas, suggest that naturalistic objects in motion are processed at multiple stages of multisensory integration. The pattern of integration effects differed considerably for non-naturalistic stimuli. Unlike naturalistic objects, no early interactions were found for non-naturalistic objects. The earliest integration effects for non-naturalistic stimuli were observed 210-250 ms after sound onset including large portions of the inferior parietal cortex (IPC). As such, there were clear differences in the cortical networks activated by multisensory motion stimuli as a consequence of the semantic relatedness (or lack thereof) of the constituent sensory elements.

  10. The neural dynamics of somatosensory processing and adaptation across childhood: a high-density electrical mapping study

    PubMed Central

    Uppal, Neha; Foxe, John J.; Butler, John S.; Acluche, Frantzy

    2016-01-01

    Young children are often hyperreactive to somatosensory inputs hardly noticed by adults, as exemplified by irritation to seams or labels in clothing. The neurodevelopmental mechanisms underlying changes in sensory reactivity are not well understood. Based on the idea that neurodevelopmental changes in somatosensory processing and/or changes in sensory adaptation might underlie developmental differences in somatosensory reactivity, high-density electroencephalography was used to examine how the nervous system responds and adapts to repeated vibrotactile stimulation over childhood. Participants aged 6–18 yr old were presented with 50-ms vibrotactile stimuli to the right wrist over the median nerve at 5 blocked interstimulus intervals (ranging from ∼7 to ∼1 stimulus per second). Somatosensory evoked potentials (SEPs) revealed three major phases of activation within the first 200 ms, with scalp topographies suggestive of neural generators in contralateral somatosensory cortex. Although overall SEPs were highly similar for younger, middle, and older age groups (6.1–9.8, 10.0–12.9, and 13.0–17.8 yr old), there were significant age-related amplitude differences in initial and later phases of the SEP. In contrast, robust adaptation effects for fast vs. slow presentation rates were observed that did not differ as a function of age. A greater amplitude response in the later portion of the SEP was observed for the youngest group and may be related to developmental changes in responsivity to somatosensory stimuli. These data suggest the protracted development of the somatosensory system over childhood, whereas adaptation, as assayed in this study, is largely in place by ∼7 yr of age. PMID:26763781

  11. Impact of increases in high-density lipoprotein cholesterol on cardiovascular outcomes during the armed forces regression study.

    PubMed

    Devendra, Ganesh P; Whitney, Edwin J; Krasuski, Richard A

    2010-12-01

    high-density lipoprotein (HDL) cholesterol is a well-established inverse risk factor for cardiovascular disease. The extent to which cardiovascular risk can be modified through changes in HDL, however, is less clear. We further examined the role of aggressive HDL raising therapy on cardiovascular outcomes in the 143 patients enrolled in the Armed Forces Regression Study (AFREGS). reanalysis of the AFREGS population. Patients with stable coronary disease were randomized to receive gemfibrozil, niacin, and cholestyramine in combination or matching placebos, on top of aggressive dietary and exercise modification for a 30-month period. Blood work was performed at baseline and repeated after 1 year of therapy. patients were divided into 3 groups based on their therapeutic response: no HDL increase, mild HDL increase, and large HDL increase (% change in HDL ≤ 0, ≤ the lower 2 tertiles of HDL increase, and > the upper tertile of HDL increase, respectively). A progressive decrease in cardiovascular events was noted across these groups (30.4%, 19.4%, and 3.2%, respectively, P = .01). Kaplan-Meier analysis according to percentage change in HDL demonstrated a similar improvement in event-free survival (P = .01). Proportional hazards modeling also demonstrated that increasing HDL predicted a lower hazard of cardiovascular events, even after adjusting for changes in low-density lipoprotein ([LDL] P < .01). For every 1% increase in HDL achieved, a 2% decrease in events was recognized. these data suggest that in a population of patients with stable atherosclerosis, the greater the percentage increase in HDL achieved, the greater the cardioprotective benefit. This further supports HDL raising as a beneficial therapeutic strategy.

  12. PAGAT gel dosimeters for dose distribution measurements in the vicinity of high-density implants: A preliminary study

    NASA Astrophysics Data System (ADS)

    Asena, A.; Kairn, T.; Crowe, S. B.; Smith, S. T.; Trapp, J. V.

    2015-01-01

    This work examined the suitability of the PAGAT gel dosimeter for use in dose distribution measurements around high-density implants. An assessment of the gels reactivity with various metals was performed and no corrosive effects were observed. An artefact reduction technique was also investigated in order to minimise scattering of the laser light in the optical CT scans. The potential for attenuation and backscatter measurements using this gel dosimeter were examined for a temporary tissue expander's internal magnetic port.

  13. Feasibility Study to Evaluate Candidate Materials of Nanofilled Block Copolymers for Use in Ultra High Density Pulsed Power Capacitors

    DTIC Science & Technology

    2015-10-26

    power capacitors Dharmaraj Raghavan HOWARD UNIV WASHINGTON DC Final Report 10/26/2015 DISTRIBUTION A: Distribution approved for public release. AF Office...materials of nanofilled block copolymers for use in ultra high density pulsed power capacitors 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-12-1-0306...permittivity of inorganic fillers with the high breakdoen strength (Ebd) of polymer matrix to obtain high energy density capacitors . Our strategy of

  14. Brain activity and medical diagnosis: an EEG study

    PubMed Central

    2013-01-01

    Background Despite new brain imaging techniques that have improved the study of the underlying processes of human decision-making, to the best of our knowledge, there have been very few studies that have attempted to investigate brain activity during medical diagnostic processing. We investigated brain electroencephalography (EEG) activity associated with diagnostic decision-making in the realm of veterinary medicine using X-rays as a fundamental auxiliary test. EEG signals were analysed using Principal Components (PCA) and Logistic Regression Analysis Results The principal component analysis revealed three patterns that accounted for 85% of the total variance in the EEG activity recorded while veterinary doctors read a clinical history, examined an X-ray image pertinent to a medical case, and selected among alternative diagnostic hypotheses. Two of these patterns are proposed to be associated with visual processing and the executive control of the task. The other two patterns are proposed to be related to the reasoning process that occurs during diagnostic decision-making. Conclusions PCA analysis was successful in disclosing the different patterns of brain activity associated with hypothesis triggering and handling (pattern P1); identification uncertainty and prevalence assessment (pattern P3), and hypothesis plausibility calculation (pattern P2); Logistic regression analysis was successful in disclosing the brain activity associated with clinical reasoning success, and together with regression analysis showed that clinical practice reorganizes the neural circuits supporting clinical reasoning. PMID:24083668

  15. Pharmaco-EEG: A Study of Individualized Medicine in Clinical Practice.

    PubMed

    Swatzyna, Ronald J; Kozlowski, Gerald P; Tarnow, Jay D

    2015-07-01

    Pharmaco-electroencephalography (Pharmaco-EEG) studies using clinical EEG and quantitative EEG (qEEG) technologies have existed for more than 4 decades. This is a promising area that could improve psychotropic intervention using neurological data. One of the objectives in our clinical practice has been to collect EEG and quantitative EEG (qEEG) data. In the past 5 years, we have identified a subset of refractory cases (n = 386) found to contain commonalities of a small number of electrophysiological features in the following diagnostic categories: mood, anxiety, autistic spectrum, and attention deficit disorders, Four abnormalities were noted in the majority of medication failure cases and these abnormalities did not appear to significantly align with their diagnoses. Those were the following: encephalopathy, focal slowing, beta spindles, and transient discharges. To analyze the relationship noted, they were tested for association with the assigned diagnoses. Fisher's exact test and binary logistics regression found very little (6%) association between particular EEG/qEEG abnormalities and diagnoses. Findings from studies of this type suggest that EEG/qEEG provides individualized understanding of pharmacotherapy failures and has the potential to improve medication selection.

  16. Subfractions of High-Density Lipoprotein-Cholesterol and Carotid Intima-Media Thickness: The Northern Manhattan Study.

    PubMed

    Tiozzo, Eduard; Gardener, Hannah; Hudson, Barry I; Dong, Chuanhui; Della-Morte, David; Crisby, Milita; Goldberg, Ronald B; Elkind, Mitchell S V; Cheung, Ying Kuen; Wright, Clinton B; Sacco, Ralph L; Desvarieux, Moise; Rundek, Tatjana

    2016-06-01

    Recent drug trials have challenged the high-density lipoprotein-cholesterol (HDL-C) antiatherosclerotic hypothesis, suggesting that total level of HDL-C may not be the best target for intervention. HDL-C subfractions may be better markers of vascular risk than total levels of HDL-C. The objective of this cross-sectional study was to investigate the relationship between HDL2-C and HDL3-C fractions and carotid intima-media thickness (cIMT) in the population-based Northern Manhattan Study. We evaluated 988 stroke-free participants (mean age, 66±8 years; 60% women; 66% Hispanic, and 34% non-Hispanic) with available data on HDL-C subfractions using precipitation method and cIMT assessed by a high-resolution carotid ultrasound. The associations between HDL-C subfractions and cIMT were analyzed by multiple linear regression models. The mean HDL2-C was 14±8 mg/dL, HDL3-C 32±8 mg/dL, and the mean total HDL-C was 46±14 mg/dL. The mean cIMT was 0.90±0.08 mm. After controlling for demographics and vascular risk factors, HDL2-C and total HDL-C were inversely associated with cIMT (per 2 SDs, β=-0.017, P=0.001 and β=-0.012, P=0.03, respectively). The same inverse association was more pronounced among those with diabetes mellitus (per 2SDs, HDL2-C: β=-0.043, P=0.003 and HDL-C: β=-0.029, P=0.02). HDL3-C was not associated with cIMT. HDL2-C had greater effect on cIMT than HDL3-C in this large urban population. The effect of HDL2-C was especially pronounced among individuals with diabetes mellitus. More research is needed to determine antiatherosclerotic effects of HDL-C subfractions and their clinical relevance. © 2016 American Heart Association, Inc.

  17. Neurobiological correlates of EMDR monitoring - an EEG study.

    PubMed

    Pagani, Marco; Di Lorenzo, Giorgio; Verardo, Anna Rita; Nicolais, Giampaolo; Monaco, Leonardo; Lauretti, Giada; Russo, Rita; Niolu, Cinzia; Ammaniti, Massimo; Fernandez, Isabel; Siracusano, Alberto

    2012-01-01

    Eye Movement Desensitization and Reprocessing (EMDR) is a recognized first-line treatment for psychological trauma. However its neurobiological bases have yet to be fully disclosed. Electroencephalography (EEG) was used to fully monitor neuronal activation throughout EMDR sessions including the autobiographical script. Ten patients with major psychological trauma were investigated during their first EMDR session (T0) and during the last one performed after processing the index trauma (T1). Neuropsychological tests were administered at the same time. Comparisons were performed between EEGs of patients at T0 and T1 and between EEGs of patients and 10 controls who underwent the same EMDR procedure at T0. Connectivity analyses were carried out by lagged phase synchronization. During bilateral ocular stimulation (BS) of EMDR sessions EEG showed a significantly higher activity on the orbito-frontal, prefrontal and anterior cingulate cortex in patients at T0 shifting towards left temporo-occipital regions at T1. A similar trend was found for autobiographical script with a higher firing in fronto-temporal limbic regions at T0 moving to right temporo-occipital cortex at T1. The comparisons between patients and controls confirmed the maximal activation in the limbic cortex of patients occurring before trauma processing. Connectivity analysis showed decreased pair-wise interactions between prefrontal and cingulate cortex during BS in patients as compared to controls and between fusiform gyrus and visual cortex during script listening in patients at T1 as compared to T0. These changes correlated significantly with those occurring in neuropsychological tests. The ground-breaking methodology enabled our study to image for the first time the specific activations associated with the therapeutic actions typical of EMDR protocol. The findings suggest that traumatic events are processed at cognitive level following successful EMDR therapy, thus supporting the evidence of distinct

  18. Neurobiological Correlates of EMDR Monitoring – An EEG Study

    PubMed Central

    Pagani, Marco; Di Lorenzo, Giorgio; Verardo, Anna Rita; Nicolais, Giampaolo; Monaco, Leonardo; Lauretti, Giada; Russo, Rita; Niolu, Cinzia; Ammaniti, Massimo; Fernandez, Isabel; Siracusano, Alberto

    2012-01-01

    Background Eye Movement Desensitization and Reprocessing (EMDR) is a recognized first-line treatment for psychological trauma. However its neurobiological bases have yet to be fully disclosed. Methods Electroencephalography (EEG) was used to fully monitor neuronal activation throughout EMDR sessions including the autobiographical script. Ten patients with major psychological trauma were investigated during their first EMDR session (T0) and during the last one performed after processing the index trauma (T1). Neuropsychological tests were administered at the same time. Comparisons were performed between EEGs of patients at T0 and T1 and between EEGs of patients and 10 controls who underwent the same EMDR procedure at T0. Connectivity analyses were carried out by lagged phase synchronization. Results During bilateral ocular stimulation (BS) of EMDR sessions EEG showed a significantly higher activity on the orbito-frontal, prefrontal and anterior cingulate cortex in patients at T0 shifting towards left temporo-occipital regions at T1. A similar trend was found for autobiographical script with a higher firing in fronto-temporal limbic regions at T0 moving to right temporo-occipital cortex at T1. The comparisons between patients and controls confirmed the maximal activation in the limbic cortex of patients occurring before trauma processing. Connectivity analysis showed decreased pair-wise interactions between prefrontal and cingulate cortex during BS in patients as compared to controls and between fusiform gyrus and visual cortex during script listening in patients at T1 as compared to T0. These changes correlated significantly with those occurring in neuropsychological tests. Conclusions The ground-breaking methodology enabled our study to image for the first time the specific activations associated with the therapeutic actions typical of EMDR protocol. The findings suggest that traumatic events are processed at cognitive level following successful EMDR therapy, thus

  19. Ictal EEG/fMRI study of vertiginous seizures.

    PubMed

    Morano, Alessandra; Carnì, Marco; Casciato, Sara; Vaudano, Anna Elisabetta; Fattouch, Jinane; Fanella, Martina; Albini, Mariarita; Basili, Luca Manfredi; Lucignani, Giulia; Scapeccia, Marco; Tomassi, Regina; Di Castro, Elisabetta; Colonnese, Claudio; Giallonardo, Anna Teresa; Di Bonaventura, Carlo

    2017-03-01

    Vertigo and dizziness are extremely common complaints, related to either peripheral or central nervous system disorders. Among the latter, epilepsy has to be taken into consideration: indeed, vertigo may be part of the initial aura of a focal epileptic seizure in association with other signs/symptoms, or represent the only ictal manifestation, a rare phenomenon known as "vertiginous" or "vestibular" seizure. These ictal symptoms are usually related to a discharge arising from/involving temporal or parietal areas, which are supposed to be a crucial component of the so-called "vestibular cortex". In this paper, we describe three patients suffering from drug-resistant focal epilepsy, symptomatic of malformations of cortical development or perinatal hypoxic/ischemic lesions located in the posterior regions, who presented clusters of vertiginous seizures. The high recurrence rate of such events, recorded during video-EEG monitoring sessions, offered the opportunity to perform an ictal EEG/fMRI study to identify seizure-related hemodynamic changes. The ictal EEG/fMRI revealed the main activation clusters in the temporo-parieto-occipital regions, which are widely recognized to be involved in the processing of vestibular information. Interestingly, ictal deactivation was also detected in the ipsilateral cerebellar hemisphere, suggesting the ictal involvement of cortical-subcortical structures known to be part of the vestibular integration network.

  20. High density polyethylene (HDPE)/poly(ethylene terephthalate) (PET) polymer blend studies related to recycling co-mingled plastics

    NASA Astrophysics Data System (ADS)

    Tsai, Pang-Yen

    Polymer blends of virgin high density polyethylene (HDPE) and poly(ethylene terephthalate) (PET) were studied as an attempt to relate the microstructure to the mechanical properties of the blends. The virgin blends were prepared by extrusion and then injection molded into specimens for characterization. Two of the virgin blends were tested for possible compatibilization using a styrene-ethylene-butylene-styrene (SEBS) block copolymer. In addition, six blends of post-consumer resins (PCRs) of HDPE and PET were included in this work for comparison. The moduli of the virgin blends showed positive deviation from those expected from the rule of mixtures. The synergism of the composite moduli can be explained partly by a Poisson's effect. Yield strengths of the blends molded at low injection chamber temperatures (200sp°, 230sp°, and 250sp°C) followed the rule of mixtures well, because PET filaments found in the composites had very high length to diameter ratios. When the injection chamber temperature was above the PET melting point (˜254sp°C), PET filaments were found to break down into particles, and the yield strengths of the blends coincided with the values expected from the inverse rule of mixtures. Impact strengths of the virgin blends were much less than that of a HDPE homopolymer due to poor interfacial bonding between HDPE and PET. Compatibilization appeared to be advantageous since it dramatically improved the impact strength of the virgin blends. SEM micrographs of impact fractured surfaces revealed that the improved adhesion from compatibilization and the presence of numerous uniaxially aligned PET filaments in the HDPE substrate can account for the significant increases in fracture resistance of the compatibilized blends. Mechanical performance of the PCRs was inferior to that of the virgin blends. Aside from polymer degradation and contamination due to repeated processing and handling, absence of PET filaments and interfacial bonding could be

  1. High density fluoride glass calorimeter

    NASA Astrophysics Data System (ADS)

    Xie, Q.; Scheltzbaum, J.; Akgun, U.

    2014-04-01

    The unprecedented radiation levels in current Large Hadron Collider runs, and plans to even increase the luminosity creates a need for new detector technologies to be investigated. Quartz plates to replace the plastic scintillators in current LHC calorimeters have been proposed in recent reports. Quartz based Cherenkov calorimeters can solve the radiation damage problem, however light production and transfer have proven to be challenging. This report summarizes the results from a computational study on the performance of a high-density glass calorimeter. High-density, scintillating, fluoride glass, CHG3, was used as the active material. This glass has been developed specifically for hadron collider experiments, and is known for fast response time, in addition to high light yield. Here, the details of a Geant4 model for a sampling calorimeter prototype with 20 layers, and its hadronic as well as electromagnetic performances are reported.

  2. Target Speaker Detection with Concealed EEG Around the Ear.

    PubMed

    Mirkovic, Bojana; Bleichner, Martin G; De Vos, Maarten; Debener, Stefan

    2016-01-01

    Target speaker identification is essential for speech enhancement algorithms in assistive devices aimed toward helping the hearing impaired. Several recent studies have reported that target speaker identification is possible through electroencephalography (EEG) recordings. If the EEG system could be reduced to acceptable size while retaining the signal quality, hearing aids could benefit from the integration with concealed EEG. To compare the performance of a multichannel around-the-ear EEG system with high-density cap EEG recordings an envelope tracking algorithm was applied in a competitive speaker paradigm. The data from 20 normal hearing listeners were concurrently collected from the traditional state-of-the-art laboratory wired EEG system and a wireless mobile EEG system with two bilaterally-placed around-the-ear electrode arrays (cEEGrids). The results show that the cEEGrid ear-EEG technology captured neural signals that allowed the identification of the attended speaker above chance-level, with 69.3% accuracy, while cap-EEG signals resulted in the accuracy of 84.8%. Further analyses investigated the influence of ear-EEG signal quality and revealed that the envelope tracking procedure was unaffected by variability in channel impedances. We conclude that the quality of concealed ear-EEG recordings as acquired with the cEEGrid array has potential to be used in the brain-computer interface steering of hearing aids.

  3. Target Speaker Detection with Concealed EEG Around the Ear

    PubMed Central

    Mirkovic, Bojana; Bleichner, Martin G.; De Vos, Maarten; Debener, Stefan

    2016-01-01

    Target speaker identification is essential for speech enhancement algorithms in assistive devices aimed toward helping the hearing impaired. Several recent studies have reported that target speaker identification is possible through electroencephalography (EEG) recordings. If the EEG system could be reduced to acceptable size while retaining the signal quality, hearing aids could benefit from the integration with concealed EEG. To compare the performance of a multichannel around-the-ear EEG system with high-density cap EEG recordings an envelope tracking algorithm was applied in a competitive speaker paradigm. The data from 20 normal hearing listeners were concurrently collected from the traditional state-of-the-art laboratory wired EEG system and a wireless mobile EEG system with two bilaterally-placed around-the-ear electrode arrays (cEEGrids). The results show that the cEEGrid ear-EEG technology captured neural signals that allowed the identification of the attended speaker above chance-level, with 69.3% accuracy, while cap-EEG signals resulted in the accuracy of 84.8%. Further analyses investigated the influence of ear-EEG signal quality and revealed that the envelope tracking procedure was unaffected by variability in channel impedances. We conclude that the quality of concealed ear-EEG recordings as acquired with the cEEGrid array has potential to be used in the brain-computer interface steering of hearing aids. PMID:27512364

  4. Education research: evaluating the use of podcasting for residents during EEG instruction: a pilot study.

    PubMed

    Bensalem-Owen, Meriem; Chau, Destiny F; Sardam, Sean C; Fahy, Brenda G

    2011-08-23

    Educational methods for residents are shifting toward greater learner independence aided by technological advances. A Web-based program using a podcast was created for resident EEG instruction, replacing conventional didactics. The EEG curriculum also consisted of EEG interpretations under the tutelage of a neurophysiologist. This pilot study aimed to objectively evaluate the effectiveness of the podcast as a new teaching tool. A podcast for resident EEG instruction was implemented on the Web, replacing the traditional lecture. After Institutional Review Board approval, consent was obtained from the participating residents. Using 25-question evaluation tools, participants were assessed at baseline before any EEG instruction, and reassessed after podcasting and after 10 clinical EEG exposures. Each 25-item evaluation tool contained tracings used for clinical EEG interpretations. Scores after podcast training were also compared to scores after traditional didactic training from a previous study among anesthesiology trainees. Ten anesthesiology residents completed the study. The mean scores with standard deviations are 9.50 ± 2.92 at baseline, 13.40 ± 3.31 (p = 0.034) after the podcast, and 16.20 ± 1.87 (p = 0.019) after interpreting 10 EEGs. No differences were noted between the mean educational tool scores for those who underwent podcasting training compared to those who had undergone traditional didactic training. In this pilot study, podcast training was as effective as the prior conventional lecture in meeting the curricular goals of increasing EEG knowledge after 10 EEG interpretations as measured by assessment tools.

  5. High-Density Microfluidic Particle-Cluster-Array Device for Parallel and Dynamic Study of Interaction between Engineered Particles.

    PubMed

    Kim, Hojin; Lee, Sanghyun; Lee, Wonhyung; Kim, Joonwon

    2017-08-01

    A high-density and high-performance microfluidic particle-cluster-array device utilizing a novel hydrodynamically tunable pneumatic valve (HTPV) is reported for parallel and dynamic monitoring of the interactions taking place in particle clusters. The key concept involves passive operation of the HTPV through elastic deformation of a thin membrane using only the hydrodynamic force inherent in microchannel flows. This unique feature allows the discrete and high-density (≈30 HTPVs mm(-2) ) arrangement of numerous HTPVs in a microfluidic channel without any pneumatic connection. In addition, the HTPV achieves high-performance clustering (≈92%) of three different particles in an array format through the optimization of key design and operating parameters. Finally, a contamination-free, parallel, and dynamic biochemical analysis strategy is proposed, which employs a simple one-inlet-one-outlet device operated by the effective combination of several techniques, including particle clustering, the interactions between engineered particles, two-phase partitioning and dehydration control of aqueous plugs, and shape/color-based particle identification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Longitudinal study of EEG frequency maturation and power changes in children on the Russian North.

    PubMed

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

    2014-11-01

    The aim of the study was to reveal longitudinal changes in electroencephalogram spectral power and frequency (percentage frequency composition of EEG and alpha peak frequency) patterns in normal children from northern Russia. Fifteen children (9 girls and 6 boys) participated in the study. The resting state (eyes closed) EEGs were recorded yearly (2005-2013) from age 8 to age 16-17 for each child. EEG frequency patterns were estimated as the percentages of waves with a 1 Hz step revealed by measuring the interval durations between points crossing zero (isoline) by a curve. EEG spectral power changes were analyzed for delta (1.5-4 Hz), theta (4-7.5 Hz), alpha-1 (7.5-9.5 Hz), alpha-2 (9.5-12.5 Hz), beta-1 (12.5-18 Hz) and beta-2 (18-30 Hz) bands. According to the frequency composition of the EEG signals fast synchronous, polymorphous synchronous, polymorphous desynchronous and slow synchronous types of children EEG were revealed. These EEG types were relatively stable during adolescence. In these EEG types, the frequency patterns and spectral power dynamics with age had several common and specific features. Slow wave percentage and spectral power in the delta band remarkably decreased with age in all groups. Starting from the theta band the EEG types were characterized by different EEG spectral power changes with age. In fast synchronous EEG type, the theta and alpha-1 EEG power decreased, and the alpha-2 power increased in the occipital and parietal areas. The polymorphous synchronous type was characterized by increased both the alpha-1 and alpha-2 power with regional peculiarities. In the polymorphous desynchronous type spectral power in all bands decreased with age, and in the slow synchronous type, the alpha-1 power massively increased with age. Obtained results suggest predictive strength of the spatial-frequency patterns in EEG for its following maturation through the years.

  7. Investigation of variants identified in caucasian genome-wide association studies for plasma high-density lipoprotein cholesterol and triglycerides levels in Mexican dyslipidemic study samples.

    PubMed

    Weissglas-Volkov, Daphna; Aguilar-Salinas, Carlos A; Sinsheimer, Janet S; Riba, Laura; Huertas-Vazquez, Adriana; Ordoñez-Sánchez, Maria L; Rodriguez-Guillen, Rosario; Cantor, Rita M; Tusie-Luna, Teresa; Pajukanta, Päivi

    2010-02-01

    Although epidemiological studies have demonstrated an increased predisposition to low high-density lipoprotein cholesterol and high triglyceride levels in the Mexican population, Mexicans have not been included in any of the previously reported genome-wide association studies for lipids. We investigated 6 single-nucleotide polymorphisms associated with triglycerides, 7 with high-density lipoprotein cholesterol, and 1 with both triglycerides and high-density lipoprotein cholesterol in recent Caucasian genome-wide association studies in Mexican familial combined hyperlipidemia families and hypertriglyceridemia case-control study samples. These variants were within or near the genes ABCA1, ANGPTL3, APOA5, APOB, CETP, GALNT2, GCKR, LCAT, LIPC, LPL (2), MMAB-MVK, TRIB1, and XKR6-AMAC1L2. We performed a combined analysis of the family-based and case-control studies (n=2298) using the Z method to combine statistics. Ten of the single-nucleotide polymorphisms were nominally significant and 5 were significant after Bonferroni correction (P=2.20 x 10(-3) to 2.6 x 10(-11)) for the number of tests performed (APOA5, CETP, GCKR, and GALNT2). Interestingly, our strongest signal was obtained for triglycerides with the minor allele of rs964184 (P=2.6 x 10(-11)) in the APOA1/C3/A4/A5 gene cluster region that is significantly more common in Mexicans (27%) than in whites (12%). It is important to confirm whether known loci have a consistent effect across ethnic groups. We show replication of 5 Caucasian genome-wide association studies lipid associations in Mexicans. The remaining loci will require a comprehensive investigation to exclude or verify their significance in Mexicans. We also demonstrate that rs964184 has a large effect (odds ratio, 1.74) and is more frequent in the Mexican population, and thus it may contribute to the high predisposition to dyslipidemias in Mexicans.

  8. Atomic force microscopic study of the structure of high-density polyethylene deformed in liquid medium by crazing mechanism.

    PubMed

    Bagrov, D V; Yarysheva, A Y; Rukhlya, E G; Yarysheva, L M; Volynskii, A L; Bakeev, N F

    2014-02-01

    A procedure has been developed for the direct atomic force microscopic (AFM) examination of the native structure of high-density polyethylene (HDPE) deformed in an adsorption-active liquid medium (AALM) by the crazing mechanism. The AFM investigation has been carried out in the presence of a liquid medium under conditions preventing deformed films from shrinkage. Deformation of HDPE in AALM has been shown to proceed through the delocalized crazing mechanism and result in the development of a fibrillar-porous structure. The structural parameters of the crazed polymer have been determined. The obtained AFM images demonstrate a nanosized nonuniformity of the deformation and enable one to observe the structural rearrangements that take place in the deformed polymer after removal of the liquid medium and stress relaxation. A structural similarity has been revealed between HDPE deformed in the AALM and hard elastic polymers.

  9. Neural correlates of emotional responses to music: an EEG study.

    PubMed

    Daly, Ian; Malik, Asad; Hwang, Faustina; Roesch, Etienne; Weaver, James; Kirke, Alexis; Williams, Duncan; Miranda, Eduardo; Nasuto, Slawomir J

    2014-06-24

    This paper presents an EEG study into the neural correlates of music-induced emotions. We presented participants with a large dataset containing musical pieces in different styles, and asked them to report on their induced emotional responses. We found neural correlates of music-induced emotion in a number of frequencies over the pre-frontal cortex. Additionally, we found a set of patterns of functional connectivity, defined by inter-channel coherence measures, to be significantly different between groups of music-induced emotional responses. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Study of EEG during Sternberg Tasks with Different Direction of Arrangement for Letters

    NASA Astrophysics Data System (ADS)

    Kamihoriuchi, Kenji; Nuruki, Atsuo; Matae, Tadashi; Kurono, Asutsugu; Yunokuchi, Kazutomo

    In previous study, we recorded electroencephalogram (EEG) of patients with dementia and healthy subjects during Sternberg task. But, only one presentation method of Sternberg task was considered in previous study. Therefore, we examined whether the EEG was different in two different presentation methods wrote letters horizontally and wrote letters vertically in this study. We recorded EEG of six healthy subjects during Sternberg task using two different presentation methods. The result was not different in EEG topography of all subjects. In all subjects, correct rate increased in case of vertically arranged letters.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  12. Automated classification of pain perception using high-density electroencephalography data.

    PubMed

    Misra, Gaurav; Wang, Wei-En; Archer, Derek B; Roy, Arnab; Coombes, Stephen A

    2017-02-01

    The translation of brief, millisecond-long pain-eliciting stimuli to the subjective perception of pain is associated with changes in theta, alpha, beta, and gamma oscillations over sensorimotor cortex. However, when a pain-eliciting stimulus continues for minutes, regions beyond the sensorimotor cortex, such as the prefrontal cortex, are also engaged. Abnormalities in prefrontal cortex have been associated with chronic pain states, but conventional, millisecond-long EEG paradigms do not engage prefrontal regions. In the current study, we collected high-density EEG data during an experimental paradigm in which subjects experienced a 4-s, low- or high-intensity pain-eliciting stimulus. EEG data were analyzed using independent component analyses, EEG source localization analyses, and measure projection analyses. We report three novel findings. First, an increase in pain perception was associated with an increase in gamma and theta power in a cortical region that included medial prefrontal cortex. Second, a decrease in lower beta power was associated with an increase in pain perception in a cortical region that included the contralateral sensorimotor cortex. Third, we used machine learning for automated classification of EEG data into low- and high-pain classes. Theta and gamma power in the medial prefrontal region and lower beta power in the contralateral sensorimotor region served as features for classification. We found a leave-one-out cross-validation accuracy of 89.58%. The development of biological markers for pain states continues to gain traction in the literature, and our findings provide new information that advances this body of work.NEW & NOTEWORTHY The development of a biological marker for pain continues to gain traction in literature. Our findings show that high- and low-pain perception in human subjects can be classified with 89% accuracy using high-density EEG data from prefrontal cortex and contralateral sensorimotor cortex. Our approach represents a

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

    PubMed Central

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

    2014-01-01

    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

  14. Brain Areas Responsible for Vigilance: An EEG Source Imaging Study.

    PubMed

    Kim, Jung-Hoon; Kim, Do-Won; Im, Chang-Hwan

    2017-01-04

    Vigilance, sometimes referred to as sustained attention, is an important type of human attention as it is closely associated with cognitive activities required in various daily-life situations. Although many researchers have investigated which brain areas control the maintenance of vigilance, findings have been inconsistent. We hypothesized that this inconsistency might be due to the use of different experimental paradigms in the various studies. We found that most of the previous studies used paradigms that included specific cognitive tasks requiring a high cognitive load, which could complicate identification of brain areas associated only with vigilance. To minimize the influence of cognitive processes other than vigilance on the analysis results, we adopted the d2-test of attention, which is a well-known neuropsychological test of attention that does not require high cognitive load, and searched for brain areas at which EEG source activities were temporally correlated with fluctuation of vigilance over a prolonged period of time. EEG experiments conducted with 31 young adults showed that left prefrontal cortex activity was significantly correlated with vigilance variation in the delta, beta1, beta2, and gamma frequency bands, but not the theta and alpha frequency bands. Our study results suggest that the left prefrontal cortex plays a key role in vigilance modulation, and can therefore be used to monitor individual vigilance changes over time or serve as a potential target of noninvasive brain stimulation.

  15. Land use regression modelling of air pollution in high density high rise cities: A case study in Hong Kong.

    PubMed

    Lee, Martha; Brauer, Michael; Wong, Paulina; Tang, Robert; Tsui, Tsz Him; Choi, Crystal; Cheng, Wei; Lai, Poh-Chin; Tian, Linwei; Thach, Thuan-Quoc; Allen, Ryan; Barratt, Benjamin

    2017-03-16

    Land use regression (LUR) is a common method of predicting spatial variability of air pollution to estimate exposure. Nitrogen dioxide (NO2), nitric oxide (NO), fine particulate matter (PM2.5), and black carbon (BC) concentrations were measured during two sampling campaigns (April-May and November-January) in Hong Kong (a prototypical high-density high-rise city). Along with 365 potential geospatial predictor variables, these concentrations were used to build two-dimensional land use regression (LUR) models for the territory. Summary statistics for combined measurements over both campaigns were: a) NO2 (Mean=106μg/m(3), SD=38.5, N=95), b) NO (M=147μg/m(3), SD=88.9, N=40), c) PM2.5 (M=35μg/m(3), SD=6.3, N=64), and BC (M=10.6μg/m(3), SD=5.3, N=76). Final LUR models had the following statistics: a) NO2 (R(2)=0.46, RMSE=28μg/m(3)) b) NO (R(2)=0.50, RMSE=62μg/m(3)), c) PM2.5 (R(2)=0.59; RMSE=4μg/m(3)), and d) BC (R(2)=0.50, RMSE=4μg/m(3)). Traditional LUR predictors such as road length, car park density, and land use types were included in most models. The NO2 prediction surface values were highest in Kowloon and the northern region of Hong Kong Island (downtown Hong Kong). NO showed a similar pattern in the built-up region. Both PM2.5 and BC predictions exhibited a northwest-southeast gradient, with higher concentrations in the north (close to mainland China). For BC, the port was also an area of elevated predicted concentrations. The results matched with existing literature on spatial variation in concentrations of air pollutants and in relation to important emission sources in Hong Kong. The success of these models suggests LUR is appropriate in high-density, high-rise cities.

  16. A Preliminary Study of Muscular Artifact Cancellation in Single-Channel EEG

    PubMed Central

    Chen, Xun; Liu, Aiping; Peng, Hu; Ward, Rabab K.

    2014-01-01

    Electroencephalogram (EEG) recordings are often contaminated with muscular artifacts that strongly obscure the EEG signals and complicates their analysis. For the conventional case, where the EEG recordings are obtained simultaneously over many EEG channels, there exists a considerable range of methods for removing muscular artifacts. In recent years, there has been an increasing trend to use EEG information in ambulatory healthcare and related physiological signal monitoring systems. For practical reasons, a single EEG channel system must be used in these situations. Unfortunately, there exist few studies for muscular artifact cancellation in single-channel EEG recordings. To address this issue, in this preliminary study, we propose a simple, yet effective, method to achieve the muscular artifact cancellation for the single-channel EEG case. This method is a combination of the ensemble empirical mode decomposition (EEMD) and the joint blind source separation (JBSS) techniques. We also conduct a study that compares and investigates all possible single-channel solutions and demonstrate the performance of these methods using numerical simulations and real-life applications. The proposed method is shown to significantly outperform all other methods. It can successfully remove muscular artifacts without altering the underlying EEG activity. It is thus a promising tool for use in ambulatory healthcare systems. PMID:25275348

  17. Pharmaco-EEG Studies in Animals: An Overview of Contemporary Translational Applications.

    PubMed

    Drinkenburg, Wilhelmus H I M; Ruigt, Gé S F; Ahnaou, Abdallah

    2015-01-01

    The contemporary value of animal pharmaco-electroencephalography (p-EEG)-based applications are strongly interlinked with progress in recording and neuroscience analysis methodology. While p-EEG in humans and animals has been shown to be closely related in terms of underlying neuronal substrates, both translational and back-translational approaches are being used to address extrapolation issues and optimize the translational validity of preclinical animal p-EEG paradigms and data. Present applications build further on animal p-EEG and pharmaco-sleep EEG findings, but also on stimulation protocols, more specifically pharmaco-event-related potentials. Pharmaceutical research into novel treatments for neurological and psychiatric diseases has employed an increasing number of pharmacological as well as transgenic models to assess the potential therapeutic involvement of different neurochemical systems and novel drug targets as well as underlying neuronal connectivity and synaptic function. Consequently, p-EEG studies, now also readily applied in modeled animals, continue to have an important role in drug discovery and development, with progressively more emphasis on its potential as a central readout for target engagement and as a (translational) functional marker of neuronal circuit processes underlying normal and pathological brain functioning. In a similar vein as was done for human p-EEG studies, the contribution of animal p-EEG studies can further benefit by adherence to guidelines for methodological standardization, which are presently under construction by the International Pharmaco-EEG Society (IPEG).

  18. Tracking Dynamic Interactions Between Structural and Functional Connectivity: A TMS/EEG-dMRI Study.

    PubMed

    Amico, Enrico; Bodart, Olivier; Rosanova, Mario; Gosseries, Olivia; Heine, Lizette; Van Mierlo, Pieter; Martial, Charlotte; Massimini, Marcello; Marinazzo, Daniele; Laureys, Steven

    2017-03-01

    Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled with high-density electroencephalography (TMS/hd-EEG), TMS pulses revealed electrophysiological signatures of different cortical modules in health and disease. However, the neural underpinnings of these signatures remain unclear. Here, by applying multimodal analyses of cortical response to TMS recordings and diffusion magnetic resonance imaging (dMRI) tractography, we investigated the relationship between functional and structural features of different cortical modules in a cohort of awake healthy volunteers. For each subject, we computed directed functional connectivity interactions between cortical areas from the source-reconstructed TMS/hd-EEG recordings and correlated them with the correspondent structural connectivity matrix extracted from dMRI tractography, in three different frequency bands (α, β, γ) and two sites of stimulation (left precuneus and left premotor). Each stimulated area appeared to mainly respond to TMS by being functionally elicited in specific frequency bands, that is, β for precuneus and γ for premotor. We also observed a temporary decrease in the whole-brain correlation between directed functional connectivity and structural connectivity after TMS in all frequency bands. Notably, when focusing on the stimulated areas only, we found that the structure-function correlation significantly increases over time in the premotor area controlateral to TMS. Our study points out the importance of taking into account the major role played by different cortical oscillations when investigating the mechanisms for integration and segregation of information in the human brain.

  19. Study on Bayes Discriminant Analysis of EEG Data

    PubMed Central

    Shi, Yuan; He, DanDan; Qin, Fang

    2014-01-01

    Objective: In this paper, we have done Bayes Discriminant analysis to EEG data of experiment objects which are recorded impersonally come up with a relatively accurate method used in feature extraction and classification decisions. Methods: In accordance with the strength of α wave, the head electrodes are divided into four species. In use of part of 21 electrodes EEG data of 63 people, we have done Bayes Discriminant analysis to EEG data of six objects. Results In use of part of EEG data of 63 people, we have done Bayes Discriminant analysis, the electrode classification accuracy rates is 64.4%. Conclusions: Bayes Discriminant has higher prediction accuracy, EEG features (mainly αwave) extract more accurate. Bayes Discriminant would be better applied to the feature extraction and classification decisions of EEG data. PMID:25852784

  20. The utility of EEG band power analysis in the study of infancy and early childhood.

    PubMed

    Saby, Joni N; Marshall, Peter J

    2012-01-01

    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.

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

    PubMed Central

    Saby, Joni N.; Marshall, Peter J.

    2012-01-01

    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

  2. Towards optimal multi-channel EMG electrode configurations in muscle force estimation: a high density EMG study.

    PubMed

    Staudenmann, Didier; Kingma, Idsart; Stegeman, Dick F; van Dieën, Jaap H

    2005-02-01

    Surface EMG is an important tool in biomechanics, kinesiology and neurophysiology. In neurophysiology the concept of high-density EMG (HD-EMG), using two dimensional electrode grids, was developed for the measurement of spatiotemporal activation patterns of the underlying muscle and its motor units (MU). The aim of this paper was to determine, with the aid of a HD-EMG grid, the relative importance of a number of electrode sensor configurations for optimizing muscle force estimation. Sensor configurations are distinguished in two categories. The first category concerns dimensions: the size of a single electrode and the inter electrode distance (IED). The second category concerns the sensor's spatial distribution: the total area from which signals are obtained (collection surface) and the number of electrodes per cm(2) (collection density). Eleven subjects performed isometric arm extensions at three elbow angles and three contraction levels. Surface-EMG from the triceps brachii muscle and the external force at the wrist were measured. Compared to a single conventional bipolar electrode pair, the force estimation quality improved by about 30% when using HD-EMG. Among the sensor configurations, the collection surface alone appeared to be responsible for the major part of the EMG based force estimation quality by improving it with 25%.

  3. Development of a high-density gas-jet target for nuclear astrophysics and reaction studies with rare isotope beams. Final Report

    SciTech Connect

    Uwe, Greife

    2014-08-12

    The purpose of this project was to develop a high-density gas jet target that will enable a new program of transfer reaction studies with rare isotope beams and targets of hydrogen and helium that is not currently possible and will have an important impact on our understanding of stellar explosions and of the evolution of nuclear shell structure away from stability. This is the final closeout report for the project.

  4. Spatio-temporal dynamics of adaptation in the human visual system: A high-density electrical mapping study

    PubMed Central

    Andrade, Gizely N.; Butler, John S.; Mercier, Manuel R.; Molholm, Sophie; Foxe, John J.

    2015-01-01

    When sensory inputs are presented serially, response amplitudes to stimulus repetitions generally decrease as a function of presentation rate, diminishing rapidly as inter-stimulus-intervals (ISIs) fall below a second. This “adaptation” is believed to represent mechanisms by which sensory systems reduce responsivity to consistent environmental inputs, freeing resources to respond to potentially more relevant inputs. While auditory adaptation functions have been relatively well-characterized, considerably less is known about visual adaptation in humans. Here, high-density visual evoked potentials (VEPs) were recorded while two paradigms were used to interrogate visual adaptation. The first presented stimulus pairs with varying ISIs, comparing VEP amplitude to the second stimulus to that of the first (paired-presentation). The second involved blocks of stimulation (N=100) at various ISIs and comparison of VEP amplitude between blocks of differing ISIs (block-presentation). Robust VEP modulations were evident as a function of presentation rate in the block-paradigm with strongest modulations in the 130–150ms and 160–180ms visual processing phases. In paired-presentations, with ISIs of just 200–300 ms, an enhancement of VEP was evident when comparing S2 to S1, with no significant effect of presentation rate. Importantly, in block-presentations, adaptation effects were statistically robust at the individual participant level. These data suggest that a more taxing block-presentation paradigm is better suited to engage visual adaptation mechanisms than a paired-presentation design. The increased sensitivity of the visual processing metric obtained in the block-paradigm has implications for the examination of visual processing deficits in clinical populations. PMID:25688539

  5. Spatio-temporal dynamics of adaptation in the human visual system: a high-density electrical mapping study.

    PubMed

    Andrade, Gizely N; Butler, John S; Mercier, Manuel R; Molholm, Sophie; Foxe, John J

    2015-04-01

    When sensory inputs are presented serially, response amplitudes to stimulus repetitions generally decrease as a function of presentation rate, diminishing rapidly as inter-stimulus intervals (ISIs) fall below 1 s. This 'adaptation' is believed to represent mechanisms by which sensory systems reduce responsivity to consistent environmental inputs, freeing resources to respond to potentially more relevant inputs. While auditory adaptation functions have been relatively well characterized, considerably less is known about visual adaptation in humans. Here, high-density visual-evoked potentials (VEPs) were recorded while two paradigms were used to interrogate visual adaptation. The first presented stimulus pairs with varying ISIs, comparing VEP amplitude to the second stimulus with that of the first (paired-presentation). The second involved blocks of stimulation (N = 100) at various ISIs and comparison of VEP amplitude between blocks of differing ISIs (block-presentation). Robust VEP modulations were evident as a function of presentation rate in the block-paradigm, with strongest modulations in the 130-150 ms and 160-180 ms visual processing phases. In paired-presentations, with ISIs of just 200-300 ms, an enhancement of VEP was evident when comparing S2 with S1, with no significant effect of presentation rate. Importantly, in block-presentations, adaptation effects were statistically robust at the individual participant level. These data suggest that a more taxing block-presentation paradigm is better suited to engage visual adaptation mechanisms than a paired-presentation design. The increased sensitivity of the visual processing metric obtained in the block-paradigm has implications for the examination of visual processing deficits in clinical populations.

  6. Going local: insights from EEG and stereo-EEG studies of the human sleep-wake cycle.

    PubMed

    Ferrara, Michele; De Gennaro, Luigi

    2011-01-01

    In the present paper, we reviewed a large body of evidence, mainly from quantitative EEG studies of our laboratory, supporting the notion that sleep is a local and use-dependent process. Quantitative analyses of sleep EEG recorded from multiple cortical derivations clearly indicate that every sleep phenomenon, from sleep onset to the awakening, is strictly local in nature. Sleep onset first occurs in frontal areas, and a frontal predominance of low-frequency power persists in the first part of the night, when the homeostatic processes mainly occur, and then it vanishes. Upon awakening, we showed an asynchronous EEG activation of different cortical areas, the more anterior ones being the first to wake up. During extended periods of wakefulness, the increase of sleepiness-related low-EEG frequencies is again evident over the frontal derivations. Similarly, experimental manipulations of sleep length by total sleep deprivation, partial sleep curtailment or even selective slow-wave sleep deprivation lead to a slow-wave activity rebound localized especially on the anterior derivations. Thus, frontal areas are crucially involved in sleep homeostasis. According to the local use-dependent theory, this would derive from a higher sleep need of the frontal cortex, which in turn is due to its higher levels of activity during wakefulness. The fact that different brain regions can simultaneously exhibit different sleep intensities indicates that sleep is not a spatially global and uniform state, as hypothesized in the theory. We have also reviewed recent evidence of localized effects of learning and plasticity on EEG sleep measures. These studies provide crucial support to a key concept in the theory, the one claiming that local sleep characteristics should be use-dependent. Finally, we have reported data corroborating the notion that sleep is not necessarily present simultaneously in the entire brain. Our stereo-EEG recordings clearly indicate that sleep and wakefulness can co

  7. EEG interpretation reliability and interpreter confidence: a large single-center study.

    PubMed

    Grant, Arthur C; Abdel-Baki, Samah G; Weedon, Jeremy; Arnedo, Vanessa; Chari, Geetha; Koziorynska, Ewa; Lushbough, Catherine; Maus, Douglas; McSween, Tresa; Mortati, Katherine A; Reznikov, Alexandra; Omurtag, Ahmet

    2014-03-01

    The intrarater and interrater reliability (I&IR) of EEG interpretation has significant implications for the value of EEG as a diagnostic tool. We measured both the intrarater reliability and the interrater reliability of EEG interpretation based on the interpretation of complete EEGs into standard diagnostic categories and rater confidence in their interpretations and investigated sources of variance in EEG interpretations. During two distinct time intervals, six board-certified clinical neurophysiologists classified 300 EEGs into one or more of seven diagnostic categories and assigned a subjective confidence to their interpretations. Each EEG was read by three readers. Each reader interpreted 150 unique studies, and 50 studies were re-interpreted to generate intrarater data. A generalizability study assessed the contribution of subjects, readers, and the interaction between subjects and readers to interpretation variance. Five of the six readers had a median confidence of ≥99%, and the upper quartile of confidence values was 100% for all six readers. Intrarater Cohen's kappa (κc) ranged from 0.33 to 0.73 with an aggregated value of 0.59. Cohen's kappa ranged from 0.29 to 0.62 for the 15 reader pairs, with an aggregated Fleiss kappa of 0.44 for interrater agreement. Cohen's kappa was not significantly different across rater pairs (chi-square=17.3, df=14, p=0.24). Variance due to subjects (i.e., EEGs) was 65.3%, due to readers was 3.9%, and due to the interaction between readers and subjects was 30.8%. Experienced epileptologists have very high confidence in their EEG interpretations and low to moderate I&IR, a common paradox in clinical medicine. A necessary, but insufficient, condition to improve EEG interpretation accuracy is to increase intrarater and interrater reliability. This goal could be accomplished, for instance, with an automated online application integrated into a continuing medical education module that measures and reports EEG I&IR to individual

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  9. Maturation of EEG Power Spectra in Early Adolescence: A Longitudinal Study

    ERIC Educational Resources Information Center

    Cragg, Lucy; Kovacevic, Natasa; McIntosh, Anthony Randal; Poulsen, Catherine; Martinu, Kristina; Leonard, Gabriel; Paus, Tomas

    2011-01-01

    This study investigated the fine-grained development of the EEG power spectra in early adolescence, and the extent to which it is reflected in changes in peak frequency. It also sought to determine whether sex differences in the EEG power spectra reflect differential patterns of maturation. A group of 56 adolescents were tested at age 10 years and…

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  11. Maturation of EEG Power Spectra in Early Adolescence: A Longitudinal Study

    ERIC Educational Resources Information Center

    Cragg, Lucy; Kovacevic, Natasa; McIntosh, Anthony Randal; Poulsen, Catherine; Martinu, Kristina; Leonard, Gabriel; Paus, Tomas

    2011-01-01

    This study investigated the fine-grained development of the EEG power spectra in early adolescence, and the extent to which it is reflected in changes in peak frequency. It also sought to determine whether sex differences in the EEG power spectra reflect differential patterns of maturation. A group of 56 adolescents were tested at age 10 years and…

  12. Validation of a low-cost EEG device for mood induction studies.

    PubMed

    Rodríguez, Alejandro; Rey, Beatriz; Alcañiz, Mariano

    2013-01-01

    New electroencephalography (EEG) devices, more portable and cheaper, are appearing on the market. Studying the reliability of these EEG devices for emotional studies would be interesting, as these devices could be more economical and compatible with Virtual Reality (VR) settings. Therefore, the aim in this work was to validate a low-cost EEG device (Emotiv Epoc) to monitor brain activity during a positive emotional induction procedure. Emotional pictures (IAPS) were used to induce a positive mood in sixteen participants. Changes in the brain activity of subjects were compared between positive induction and neutral conditions. Obtained results were in accordance with previous scientific literature regarding frontal EEG asymmetry, which supports the possibility of using this low-cost EEG device in future mood induction studies combined with VR.

  13. Treating Addiction: Perspectives from EEG and Imaging Studies on Psychedelics.

    PubMed

    Tófoli, L F; de Araujo, D B

    2016-01-01

    Despite reports of apparent benefits, social and political pressure beginning in the late 1960s effectively banned scientific inquiry into psychedelic substances. Covert examination of psychedelics persisted through the 1990s; the turn of the century and especially the past 10 years, however, has seen a resurgent interest in psychedelic substances (eg, LSD, ayahuasca, psilocybin). This chapter outlines relevant EEG and brain imaging studies evaluating the effects of psychedelics on the brain. This chapter also reviews evidence of the use of psychedelics as adjunct therapy for a number of psychiatric and addictive disorders. In particular, psychedelics appear to have efficacy in treating depression and alcohol-use disorders. © 2016 Elsevier Inc. All rights reserved.

  14. Prospective Cohort Study Evaluating the Prognostic Value of Simple EEG Parameters in Postanoxic Coma.

    PubMed

    Azabou, Eric; Fischer, Catherine; Mauguiere, François; Vaugier, Isabelle; Annane, Djillali; Sharshar, Tarek; Lofaso, Fréderic

    2016-01-01

    We prospectively studied early bedside standard EEG characteristics in 61 acute postanoxic coma patients. Five simple EEG features, namely, isoelectric, discontinuous, nonreactive to intense auditory and nociceptive stimuli, dominant delta frequency, and occurrence of paroxysms were classified yes or no. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC) of each of these variables for predicting an unfavorable outcome, defined as death, persistent vegetative state, minimally conscious state, or severe neurological disability, as assessed 1 year after coma onset were computed as well as Synek's score. The outcome was unfavorable in 56 (91.8%) patients. Sensitivity, specificity, PPV, NPV, and AUC of nonreactive EEG for predicting an unfavorable outcome were 84%, 80%, 98%, 31%, and 0.82, respectively; and were all very close to the ones of Synek score>3, which were 82%, 80%, 98%, 29%, and 0.81, respectively. Specificities for predicting an unfavorable outcome were 100% for isoelectric, discontinuous, or dominant delta activity EEG. These 3 last features were constantly associated to unfavorable outcome. Absent EEG reactivity strongly predicted an unfavorable outcome in postanoxic coma, and performed as accurate as a Synek score>3. Analyzing characteristics of some simple EEG features may easily help nonneurophysiologist physicians to investigate prognostic issue of postanoxic coma patient. In this study (a) discontinuous, isoelectric, or delta-dominant EEG were constantly associated with unfavorable outcome and (b) nonreactive EEG performed prognostic as accurate as a Synek score>3.

  15. High density circuit technology

    NASA Technical Reports Server (NTRS)

    Wade, T. E.

    1979-01-01

    Polyimide dielectric materials were acquired for comparative and evaluative studies in double layer metal processes. Preliminary experiments were performed. Also, the literature indicates that sputtered aluminum films may be successfully patterned using the left-off technique provided the substrate temperature remains low and the argon pressure in the chamber is relatively high at the time of sputtering. Vendors associated with dry processing equipment are identified. A literature search relative to future trends in VLSI fabrication techniques is described.

  16. High density circuit technology

    NASA Technical Reports Server (NTRS)

    Wade, T. E.

    1980-01-01

    Acquisition of polyimide materials for inter-metal dielectrics was obtained from three vendors, with considerable evaluation conducted on the Dupont PI2550 material. Experimental results indicate this material can be patterned using contact printing to line width far below 0.1 mils. Optimum line width is acquired using plasma etch equipment. Metal lift-off experiments on thermal evaporated films were optimized for application to sputtered deposited films. Alternate metal-lift-off experiments are proposed for future investigation. Dry processing equipment studies and future trends in VLSI fabrication techniques are on-going.

  17. Depressive symptoms and baseline prefrontal EEG alpha activity: a study utilizing Ecological Momentary Assessment.

    PubMed

    Putnam, Katherine M; McSweeney, Lauren B

    2008-02-01

    Prefrontal cortex (PFC) electroencephalography (EEG) alpha asymmetry has been found in individuals with major depression. However, EEG activity has never been examined in regard to specific depressive symptoms. We examine the relationship between resting baseline PFC alpha activity and both rumination and self-esteem in a depressed outpatient group (N=6) and a healthy control group (N=7) using high-density EEG sampling and multiple longitudinal self report measures, i.e. Ecological Momentary Assessment (EMA). Symptom measures were collected five times daily for 7 days, i.e. 35 assessments. Using a mixed-level analysis, significant Group x Hemisphere interactions for PFC sites and both rumination and self-esteem were found. Within the depressed group, lower bilateral PFC activity predicted higher levels of rumination, and lower right PFC activity predicted higher levels of self-esteem. There were no significant effects for the control group. Results indicate that specific symptoms of depression are uniquely associated with patterns of PFC EEG alpha activity.

  18. Development of cortical motor circuits between childhood and adulthood: A navigated TMS-HdEEG study.

    PubMed

    Määttä, Sara; Könönen, Mervi; Kallioniemi, Elisa; Lakka, Timo; Lintu, Niina; Lindi, Virpi; Ferreri, Florinda; Ponzo, David; Säisänen, Laura

    2017-02-20

    Motor functions improve during childhood and adolescence, but little is still known about the development of cortical motor circuits during early life. To elucidate the neurophysiological hallmarks of motor cortex development, we investigated the differences in motor cortical excitability and connectivity between healthy children, adolescents, and adults by means of navigated suprathreshold motor cortex transcranial magnetic stimulation (TMS) combined with high-density electroencephalography (EEG). We demonstrated that with development, the excitability of the motor system increases, the TMS-evoked EEG waveform increases in complexity, the magnitude of induced activation decreases, and signal spreading increases. Furthermore, the phase of the oscillatory response to TMS becomes less consistent with age. These changes parallel an improvement in manual dexterity and may reflect developmental changes in functional connectivity. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

  19. Wake High-Density Electroencephalographic Spatiospectral Signatures of Insomnia

    PubMed Central

    Colombo, Michele A.; Ramautar, Jennifer R.; Wei, Yishul; Gomez-Herrero, Germán; Stoffers, Diederick; Wassing, Rick; Benjamins, Jeroen S.; Tagliazucchi, Enzo; van der Werf, Ysbrand D.; Cajochen, Christian; Van Someren, Eus J.W.

    2016-01-01

    Study Objectives: Although daytime complaints are a defining characteristic of insomnia, most EEG studies evaluated sleep only. We used high-density electroencephalography to investigate wake resting state oscillations characteristic of insomnia disorder (ID) at a fine-grained spatiospectral resolution. Methods: A case-control assessment during eyes open (EO) and eyes closed (EC) was performed in a laboratory for human physiology. Participants (n = 94, 74 female, 21–70 y) were recruited through www.sleepregistry.nl: 51 with ID, according to DSM-5 and 43 matched controls. Exclusion criteria were any somatic, neurological or psychiatric condition. Group differences in the spectral power topographies across multiple frequencies (1.5 to 40 Hz) were evaluated using permutation-based inference with Threshold-Free Cluster-Enhancement, to correct for multiple comparisons. Results: As compared to controls, participants with ID showed less power in a narrow upper alpha band (11–12.7 Hz, peak: 11.7 Hz) over bilateral frontal and left temporal regions during EO, and more power in a broad beta frequency range (16.3–40 Hz, peak: 19 Hz) globally during EC. Source estimates suggested global rather than cortically localized group differences. Conclusions: The widespread high power in a broad beta band reported previously during sleep in insomnia is present as well during eyes closed wakefulness, suggestive of a round-the-clock hyperarousal. Low power in the upper alpha band during eyes open is consistent with low cortical inhibition and attentional filtering. The fine-grained HD-EEG findings suggest that, while more feasible than PSG, wake EEG of short duration with a few well-chosen electrodes and frequency bands, can provide valuable features of insomnia. Citation: Colombo MA, Ramautar JR, Wei Y, Gomez-Herrero G, Stoffers D, Wassing R, Benjamins JS, Tagliazucchi E, van der Werf YD, Cajochen C, Van Someren EJW. Wake high-density electroencephalographic spatiospectral

  20. Study of the influence of a strong magnetic field on the composition of nuclear matter at high densities and zero temperature

    SciTech Connect

    Coelho, Eduardo L.; Chiapparini, Marcelo; Bracco, Mirian E.

    2013-03-25

    Magnetars are neutron stars with a strong surface magnetic field. Observations of soft gamma-ray and anomalous X-ray pulsars pointed out that the surface magnetic field of magnetars is equal or even greater than 10{sup 15} G. In this work we study the influence of a strong magnetic field on the composition of nuclear matter at high densities and zero temperature. We describe the matter through a relativistic mean-field model with eight light baryons (baryon octet), electrons, muons and with magnetic field. As output of the numerical calculations, we obtain the relative population of each species of particles as function of baryon density.

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

    PubMed

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

    2014-10-01

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

  2. EEG-fMRI integration for the study of human brain function.

    PubMed

    Jorge, João; van der Zwaag, Wietske; Figueiredo, Patrícia

    2014-11-15

    Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have proved to be extremely valuable tools for the non-invasive study of human brain function. Moreover, due to a notable degree of complementarity between the two modalities, the combination of EEG and fMRI data has been actively sought in the last two decades. Although initially focused on epilepsy, EEG-fMRI applications were rapidly extended to the study of healthy brain function, yielding new insights into its underlying mechanisms and pathways. Nevertheless, EEG and fMRI have markedly different spatial and temporal resolutions, and probe neuronal activity through distinct biophysical processes, many aspects of which are still poorly understood. The remarkable conceptual and methodological challenges associated with EEG-fMRI integration have motivated the development of a wide range of analysis approaches over the years, each relying on more or less restrictive assumptions, and aiming to shed further light on the mechanisms of brain function along with those of the EEG-fMRI coupling itself. Here, we present a review of the most relevant EEG-fMRI integration approaches yet proposed for the study of brain function, supported by a general overview of our current understanding of the biophysical mechanisms coupling the signals obtained from the two modalities.

  3. Serum high-density lipoprotein is associated with better cognitive function in a cross-sectional study of aging women.

    PubMed

    Bates, Kristyn A; Sohrabi, Hamid R; Rainey-Smith, Stephanie R; Weinborn, Michael; Bucks, Romola S; Rodrigues, Mark; Beilby, John; Howard, Matthew; Taddei, Kevin; Martins, Georgia; Paton, Athena; Shah, Tejal; Dhaliwal, Satvinder S; Foster, Jonathan K; Martins, Ian J; Lautenschlager, Nicola T; Mastaglia, Frank L; Gandy, Samuel E; Martins, Ralph N

    2017-03-01

    Purpose/Aim of the study: Poor cardiovascular health, including obesity and altered lipid profiles at mid-life, are linked to increased risk of Alzheimer's disease (AD). The biological mechanisms linking cardiovascular health and cognitive function are unclear though are likely to be multifactorial. This study examined the association between various lipoproteins and cognitive functioning in ageing women.

  4. Cortical mechanisms of loss of consciousness: insight from TMS/EEG studies.

    PubMed

    Massimini, M; Ferrarelli, F; Sarasso, S; Tononi, G

    2012-01-01

    In a recent series of experiments we recorded the electroencephalogram (EEG) response to a direct cortical stimulation in humans during wakefulness, NREM sleep, REM sleep and anesthesia by means of a combination of transcranial magnetic stimulation (TMS) and high-density EEG (hd-EEG). TMS/hd-EEG measurements showed that, while during wakefulness and REM sleep the brain is able to sustain long-range specific patterns of activation, during NREM sleep and Midazolam-induced anesthesia, when consciousness fades, this ability is lot: the thalamocortical system, despite being active and reactive, either breaks down in causally independent modules (producing a local slow wave), or it bursts into an explosive and non-specific response (producing a global EEG slow wave). We hypothesize that, like spontaneous sleep slow waves, the slow waves triggered by TMS during sleep and anaesthesia are due to bistability between upand down-states in thalamocortical circuits. In this condition, the inescapable occurrence of a silent, down state after an initial activation impairs the ability of thalamocortical circuits to sustain long-range, differentiated patterns of activation, a theoretical requisite for consciousness. According to animal experiments and computer simulations, thalamocortical bistability may result from increased K-currents, from alterations of the balance between excitation and inhibition and from partial cortical de-afferentation. We hypothesize that these factor may play an important role in determining loss, and recovery, of consciousness also in brain-injured subjects. If this is the case, some types of brain lesions may impair information transmission, above and beyond the associated anatomical disconnection, by inducing bistability in portions of the thalamocortical system that are otherwise healthy.

  5. Studies of high density baryon matter with high intensity heavy-ion beams at J-PARC

    NASA Astrophysics Data System (ADS)

    Sako, H.; Harada, H.; Sakaguchi, T.; Chujo, T.; Esumi, S.; Gunji, T.; Hasegawa, S.; Hwang, S. H.; Ichikawa, Y.; Imai, K.; Itakura, K.; Kaneta, M.; Kim, B. C.; Kinsho, M.; Kitazawa, M.; Liu, Y.; Masui, H.; Nagamiya, S.; Nishio, K.; Okamura, M.; Oyama, K.; Ozawa, K.; Saha, P. K.; Sakaguchi, A.; Sato, S.; Shigaki, K.; Sugimura, H.; Tanida, K.; Tamura, J.; Tamura, H.; Nara, Y.; Saito, T. R.

    2016-12-01

    In J-PARC heavy-ion project, we aim at studies of QCD phase structures and hadron properties in high baryon density close to the neutron star core. We have developed a heavy-ion acceleration scheme with a new linac and a new booster with existing two synchrotrons with the goal beam rate of about 1011 Hz. We have also designed a large acceptance spectrometer based on a toroidal magnet. We have evaluated the spectrometer performance, and demonstrated reconstructing dielectron and dimuon spectra with full detector simulations. Finally, we designed a hypernuclear spectrometer which can utilize the full intensity ion beams.

  6. Feature study of hysterical blindness EEG based on FastICA with combined-channel information.

    PubMed

    Qin, Xuying; Wang, Wei; Hu, Lintao; Wang, Xu; Yuan, Xiaojie

    2015-01-01

    An appropriate feature study of hysteria electroencephalograms (EEG) would provide new insights into neural mechanisms of the disease, and also make improvements in patient diagnosis and management. The objective of this paper is to provide an explanation for what causes a particular visual loss, by associating the features of hysterical blindness EEG with brain function. An idea for the novel feature extraction for hysterical blindness EEG, utilizing combined-channel information, was applied in this paper. After channels had been combined, the sliding-window-FastICA was applied to process the combined normal EEG and hysteria EEG, respectively. Kurtosis features were calculated from the processed signals. As the comparison feature, the power spectral density of normal and hysteria EEG were computed. According to the feature analysis results, a region of brain dysfunction was located at the occipital lobe, O1 and O2. Furthermore, new abnormality was found at the parietal lobe, C3, C4, P3, and P4, that provided us with a new perspective for understanding hysterical blindness. Indicated by the kurtosis results which were consistent with brain function and the clinical diagnosis, our method was found to be a useful tool to capture features in hysterical blindness EEG.

  7. Synaptic damage underlies EEG abnormalities in postanoxic encephalopathy: A computational study.

    PubMed

    Ruijter, B J; Hofmeijer, J; Meijer, H G E; van Putten, M J A M

    2017-09-01

    In postanoxic coma, EEG patterns indicate the severity of encephalopathy and typically evolve in time. We aim to improve the understanding of pathophysiological mechanisms underlying these EEG abnormalities. We used a mean field model comprising excitatory and inhibitory neurons, local synaptic connections, and input from thalamic afferents. Anoxic damage is modeled as aggravated short-term synaptic depression, with gradual recovery over many hours. Additionally, excitatory neurotransmission is potentiated, scaling with the severity of anoxic encephalopathy. Simulations were compared with continuous EEG recordings of 155 comatose patients after cardiac arrest. The simulations agree well with six common categories of EEG rhythms in postanoxic encephalopathy, including typical transitions in time. Plausible results were only obtained if excitatory synapses were more severely affected by short-term synaptic depression than inhibitory synapses. In postanoxic encephalopathy, the evolution of EEG patterns presumably results from gradual improvement of complete synaptic failure, where excitatory synapses are more severely affected than inhibitory synapses. The range of EEG patterns depends on the excitation-inhibition imbalance, probably resulting from long-term potentiation of excitatory neurotransmission. Our study is the first to relate microscopic synaptic dynamics in anoxic brain injury to both typical EEG observations and their evolution in time. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  8. Pilot prospective study of post-surgery sleep and EEG predictors of post-operative delirium.

    PubMed

    Evans, Joanna L; Nadler, Jacob W; Preud'homme, Xavier A; Fang, Eric; Daughtry, Rommie L; Chapman, Joseph B; Attarian, David; Wellman, Samuel; Krystal, Andrew D

    2017-08-01

    Delirium is a common post-operative complication associated with significant costs, morbidity, and mortality. We sought sleep/EEG predictors of delirium present prior to delirium symptoms to facilitate developing and targeting therapies. Continuous EEG data were obtained in 12 patients post-orthopedic surgery from the day of surgery until delirium assessment on post-operative day 2 (POD2). Diminished total sleep time (r=-0.68; p<0.05) and longer latency to sleep onset (r=0.67; p<0.05) on the first night in the hospital were associated with greater POD2 delirium severity. Patients experiencing delirium slept 2.4h less and took 2h longer to fall asleep. Greater waking EEG delta power (r=0.84; p<0.05) on POD1 and less non-REM sleep EEG delta power (r=-0.72; p<0.05) on night 2 also predicted POD2 delirium severity. Loss of sleep on night1 post-surgery is an early predictor of subsequent delirium. EEG Delta Power alterations in waking and sleep appear to be later indicators of impending delirium. Further work is needed to evaluate reproducibility/generalizability and assess whether sleep loss contributes to causing delirium. This first study to prospectively collect continuous EEG data for an extended period prior to delirium onset identified EEG-derived indices that predict subsequent delirium that could aid in developing and targeting therapies. Copyright © 2017. Published by Elsevier B.V.

  9. High density of peritumoral lymphatic vessels is a potential prognostic marker of endometrial carcinoma: a clinical immunohistochemical method study.

    PubMed

    Gao, Ying; Liu, Zi; Gao, Fei; Meng, Xiao-yu

    2010-04-08

    The lymphatic system is a major route for cancer cell dissemination and also a potential target for antitumor therapy. To investigate whether increased lymphatic vessel density (LVD) is a prognostic factor for nodal metastasis and survival, we studied peritumoral LVD (P-LVD) and intratumoral LVD (I-LVD) in samples from 102 patients with endometrial carcinoma; Endometrial carcinoma tissues were analyzed for lymphatic vessels by immunohistochemical staining with an antibody against LYVE-1. Univariate analysis was performed with Kaplan-Meier life-table curves to estimate survival, and was compared using the log rank test. Prognostic models used multivariate Cox regression analysis for multivariate analyses of survival; Our study showed that P-LVD, but not I-LVD, was significantly correlated with lymph vascular space invasion (LVSI), lymph node metastasis, tumor stage, and CD44 expression in endometrial carcinoma. Moreover, P-LVD was an independent prognostic factor for progression-free survival and overall survival of endometrial carcinoma; P-LVD may serve as a prognostic factor for endometrial carcinoma. The peritumoral lymphatics might play an important role in lymphatic vessel metastasis.

  10. How wrong can we be? The effect of inaccurate mark-up of EEG/fMRI studies in epilepsy.

    PubMed

    Flanagan, Danny; Abbott, David F; Jackson, Graeme D

    2009-09-01

    The aim of this investigation was to determine the effect of inaccurate or inconsistent marking up of events in the EEG on statistical analysis of EEG/fMRI studies of patients with epilepsy. EEGs obtained during EEG/fMRI studies conducted on 10 patients with epilepsy and six normal control subjects were reviewed. All clear epileptiform events were marked up in the patient EEGs, as were all small movement-related artefacts in the patient and control subject EEGs. We then considered the effect on the numbers of voxels above threshold in the resulting Statistical Parametric Mapping (SPM) analysis if events were omitted, mislabelled, or if event times were inconsistently marked up. Omitting true epileptiform events resulted in a decrease in the number of voxels that survive statistical threshold. Mixing epileptiform and non-epileptiform events in the SPM analysis generally (but not always) decreased the number of voxels that survived threshold. Inconsistent event mark-up had little effect if the inconsistency was small (<200 ms), but had more effect if it was large (>500 ms). It is important to accurately mark-up EEGs acquired during EEG/fMRI studies in order to get the best results from subsequent analyses. Our study reveals the consequences of inaccurate review of the EEG in EEG/fMRI studies and suggests guidelines for the review of EEG in these investigations which, if followed, should result in studies of acceptable quality.

  11. Textile Electrodes for EEG Recording — A Pilot Study

    PubMed Central

    Löfhede, Johan; Seoane, Fernando; Thordstein, Magnus

    2012-01-01

    The overall aim of our research is to develop a monitoring system for neonatal intensive care units. Long-term EEG monitoring in newborns require that the electrodes don’t harm the sensitive skin of the baby, an especially relevant feature for premature babies. Our approach to EEG monitoring is based on several electrodes distributed over the head of the baby, and since the weight of the head always will be on some of them, any type of hard electrode will inevitably cause a pressure-point that can irritate the skin. Therefore, we propose the use of soft conductive textiles as EEG electrodes, primarily for neonates, but also for other kinds of unobtrusive long-term monitoring. In this paper we have tested two types of textile electrodes on five healthy adults and compared them to standard high quality electrodes. The acquired signals were compared with respect to morphology, frequency distribution, spectral coherence, correlation and power line interference sensitivity, and the signals were found to be similar in most respects. The good measurement performance exhibited by the textile electrodes indicates that they are feasible candidates for EEG recording, opening the door for long-term EEG monitoring applications. PMID:23223149

  12. Textile electrodes for EEG recording--a pilot study.

    PubMed

    Löfhede, Johan; Seoane, Fernando; Thordstein, Magnus

    2012-12-07

    The overall aim of our research is to develop a monitoring system for neonatal intensive care units. Long-term EEG monitoring in newborns require that the electrodes don't harm the sensitive skin of the baby, an especially relevant feature for premature babies. Our approach to EEG monitoring is based on several electrodes distributed over the head of the baby, and since the weight of the head always will be on some of them, any type of hard electrode will inevitably cause a pressure-point that can irritate the skin. Therefore, we propose the use of soft conductive textiles as EEG electrodes, primarily for neonates, but also for other kinds of unobtrusive long-term monitoring. In this paper we have tested two types of textile electrodes on five healthy adults and compared them to standard high quality electrodes. The acquired signals were compared with respect to morphology, frequency distribution, spectral coherence, correlation and power line interference sensitivity, and the signals were found to be similar in most respects. The good measurement performance exhibited by the textile electrodes indicates that they are feasible candidates for EEG recording, opening the door for long-term EEG monitoring applications.

  13. Study of diffusion bond development in 6061 aluminum and its relationship to future high density fuels fabrication.

    SciTech Connect

    Prokofiev, I.; Wiencek, T.; McGann, D.

    1997-10-07

    Powder metallurgy dispersions of uranium alloys and silicides in an aluminum matrix have been developed by the RERTR program as a new generation of proliferation-resistant fuels. Testing is done with miniplate-type fuel plates to simulate standard fuel with cladding and matrix in plate-type configurations. In order to seal the dispersion fuel plates, a diffusion bond must exist between the aluminum coverplates surrounding the fuel meat. Four different variations in the standard method for roll-bonding 6061 aluminum were studied. They included mechanical cleaning, addition of a getter material, modifications to the standard chemical etching, and welding methods. Aluminum test pieces were subjected to a bend test after each rolling pass. Results, based on 400 samples, indicate that at least a 70% reduction in thickness is required to produce a diffusion bond using the standard rollbonding method versus a 60% reduction using the Type II method in which the assembly was welded 100% and contained open 9mm holes at frame corners.

  14. Streaked optical pyrometry of ion heated compound targets in the study of plasma mix at high density interfaces

    NASA Astrophysics Data System (ADS)

    Dyer, Gilliss; Roycroft, Rebecca; Wagner, Craig; Bernstein, Aaron; Ditmire, Todd; Hegelich, B. Manuel; Albright, Brian; Fernández, Juan; Bang, Woosuk; Bradley, Paul; Gautier, D. Cort; Hamilton, Christopher; Palaniyappan, Sasi; Santiago Cordoba, Miguel; Vold, Erik; Lin, Yin

    2015-11-01

    The interaction and mixing of different species of plasma at high energy density is of fundamental interest for HED physics and relevant to inertial confinement fusion. An ongoing campaign is underway at the Trident laser facility to study the dynamics at the interface of high and low atomic number materials under warm dense matter conditions. The experiments utilize laser-accelerated ions, such as aluminum, to flash heat solid targets to temperatures >1 eV. We report on streaked pyrometry measurements made in a recent experimental run, which shed light on the dynamics of heating induced in various target materials by these ion sources. Timescale as well as spatial extent of the heating can vary greatly depending on the dominant ion species and spectra. This work was supported by NNSA cooperative agreement DE-NA0002008 and the Los Alamos National Laboratory Directed Research and Development Program under the auspices of the U.S. DOE NNSAS, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06.

  15. The interconnection of mental fatigue and aging: An EEG study.

    PubMed

    Arnau, Stefan; Möckel, Tina; Rinkenauer, Gerhard; Wascher, Edmund

    2017-07-01

    Mental fatigue, a state of reduced alertness and decreased overall performance due to prolonged cognitive activity, is a major cause for a large number of accidents in traffic and industry. Against the background of an aging workforce, the investigation of the interconnection of mental fatigue and aging is of great practical relevance. In the present study, a group of younger and a group of older adults performed a cognitive task for 3h. The experimental design also comprised breaks with various durations. Beside behavioral data, the spectral properties of the ongoing EEG with respect to time on task and breaks were analyzed. No differences between the age groups were found in behavior, but electrophysiological measures provide some evidence that older adults in our study were differentially affected by time on task. In the later course of the experiment modulations in frontal theta power became larger for older, compared to younger adults. This may indicate strain due to task demands, eventually resulting from the deployment of compensatory processes. Occipital alpha, which has been linked to internally oriented brain states, saturates faster in younger adults. It thus maybe, that especially the younger participants' performance deteriorated due to the monotonous nature of the task itself. Both mechanisms, an increased consumption of cognitive resources in older adults and a decrease of motivation in younger adults, could mask differences in performance decrements between the age groups due to mental fatigue. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Real-Time Adaptive EEG Source Separation Using Online Recursive Independent Component Analysis.

    PubMed

    Hsu, Sheng-Hsiou; Mullen, Tim R; Jung, Tzyy-Ping; Cauwenberghs, Gert

    2016-03-01

    Independent component analysis (ICA) has been widely applied to electroencephalographic (EEG) biosignal processing and brain-computer interfaces. The practical use of ICA, however, is limited by its computational complexity, data requirements for convergence, and assumption of data stationarity, especially for high-density data. Here we study and validate an optimized online recursive ICA algorithm (ORICA) with online recursive least squares (RLS) whitening for blind source separation of high-density EEG data, which offers instantaneous incremental convergence upon presentation of new data. Empirical results of this study demonstrate the algorithm's: 1) suitability for accurate and efficient source identification in high-density (64-channel) realistically-simulated EEG data; 2) capability to detect and adapt to nonstationarity in 64-ch simulated EEG data; and 3) utility for rapidly extracting principal brain and artifact sources in real 61-channel EEG data recorded by a dry and wearable EEG system in a cognitive experiment. ORICA was implemented as functions in BCILAB and EEGLAB and was integrated in an open-source Real-time EEG Source-mapping Toolbox (REST), supporting applications in ICA-based online artifact rejection, feature extraction for real-time biosignal monitoring in clinical environments, and adaptable classifications in brain-computer interfaces.

  17. Real-time Adaptive EEG Source Separation using Online Recursive Independent Component Analysis

    PubMed Central

    Hsu, Sheng-Hsiou; Mullen, Tim; Jung, Tzyy-Ping; Cauwenberghs, Gert

    2016-01-01

    Independent Component Analysis (ICA) has been widely applied to electroencephalographic (EEG) biosignal processing and brain-computer interfaces. The practical use of ICA, however, is limited by its computational complexity, data requirements for convergence, and assumption of data stationarity, especially for high-density data. Here we study and validate an optimized online recursive ICA algorithm (ORICA) with online recursive least squares (RLS) whitening for blind source separation of high-density EEG data, which offers instantaneous incremental convergence upon presentation of new data. Empirical results of this study demonstrate the algorithm's: (a) suitability for accurate and efficient source identification in high-density (64-channel) realistically-simulated EEG data; (b) capability to detect and adapt to non-stationarity in 64-ch simulated EEG data; and (c) utility for rapidly extracting principal brain and artifact sources in real 61-channel EEG data recorded by a dry and wearable EEG system in a cognitive experiment. ORICA was implemented as functions in BCILAB and EEGLAB and was integrated in an open-source Real-time EEG Source-mapping Toolbox (REST), supporting applications in ICA-based online artifact rejection, feature extraction for real-time biosignal monitoring in clinical environments, and adaptable classifications in brain-computer interfaces. PMID:26685257

  18. What can be found in scalp EEG spectrum beyond common frequency bands. EEG-fMRI study

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  19. [Comparative EEG study in normal and autistic children].

    PubMed

    Lushchekina, E A; Podreznaia, E D; Lushchekin, V S; Strelets, V B

    2010-01-01

    The work represents the results of a comparative study of spectral power as well as averaged coherence in alpha, beta and gamma EEG bands in 5-to-7-year-old autistic and healthy boys in the state of rest and under cognitive load (mental calculation). The mean age of the examined children was 6 years 4 months. In both healthy and autistic children, there was a clear-cut baseline frontal-occipital gradient of the alpha activity. Performance of the cognitive task led to enhancement of spectral power in the alpha1 band and shifting its maximum to the left hemisphere, did not change the activity in the alpha2 band, and considerably increased the spectral power in the alpha3 band. In healthy children, the spectral power and average coherence of the fast rhythms increased in the central and frontal areas of the left hemisphere. The right-side dominance of the spectral power of the alpha band was revealed in autistic children both in the baseline and during cognitive task. The spectral power of the gamma band was higher in autistic children than in healthy children in the baseline. The cognitive task did not change this fast activity in autistic children.

  20. Aberrant EEG functional connectivity and EEG power spectra in resting state post-traumatic stress disorder: a sLORETA study.

    PubMed

    Imperatori, Claudio; Farina, Benedetto; Quintiliani, Maria Isabella; Onofri, Antonio; Castelli Gattinara, Paola; Lepore, Marta; Gnoni, Valentina; Mazzucchi, Edoardo; Contardi, Anna; Della Marca, Giacomo

    2014-10-01

    The aim of the present study was to explore the modifications of EEG power spectra and EEG connectivity of resting state (RS) condition in patients with post-traumatic stress disorder (PTSD). Seventeen patients and seventeen healthy subjects matched for age and gender were enrolled. EEG was recorded during 5min of RS. EEG analysis was conducted by means of the standardized Low Resolution Electric Tomography software (sLORETA). In power spectra analysis PTSD patients showed a widespread increase of theta activity (4.5-7.5Hz) in parietal lobes (Brodmann Area, BA 7, 4, 5, 40) and in frontal lobes (BA 6). In the connectivity analysis PTSD patients also showed increase of alpha connectivity (8-12.5Hz) between the cortical areas explored by Pz-P4 electrode. Our results could reflect the alteration of memory systems and emotional processing consistently altered in PTSD patients.

  1. Photoionization and High Density Gas

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Bautista, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present results of calculations using the XSTAR version 2 computer code. This code is loosely based on the XSTAR v.1 code which has been available for public use for some time. However it represents an improvement and update in several major respects, including atomic data, code structure, user interface, and improved physical description of ionization/excitation. In particular, it now is applicable to high density situations in which significant excited atomic level populations are likely to occur. We describe the computational techniques and assumptions, and present sample runs with particular emphasis on high density situations.

  2. Characterization of infant mu rhythm immediately before crawling: A high-resolution EEG study.

    PubMed

    Xiao, Ran; Qi, Xiao; Patino, Alejandro; Fagg, Andrew H; Kolobe, Thubi H A; Miller, David P; Ding, Lei

    2017-02-01

    Crawling is an important milestone in infant motor development. However, infants with developmental motor disorders can exhibit delays, or even miss, in the acquisition of crawling skill. And little information is available from the neurodevelopmental domain about the changes in brain function with intervention. The mu rhythm can potentially play a substantial role in understanding human motor development at early ages in infants, as it has in adults. Studies about the mu rhythm in infants were in coarse temporal resolution with longitudinal samples taken months or years apart. Details about the infant mu rhythm at a fine age resolution has not been fully revealed, which leads to contradictory evidence about its formulation and developmental changes of its spectral origins and, therefore, impedes the full understanding of motor brain development before crawling skill acquisition. The present study aims to expand knowledge about the infant mu rhythm and its spatio-spectral pattern shifts along maturation immediately before crawling. With high-density EEG data recorded on a weekly basis and simultaneous characterization of spatio-spectral patterns of the mu rhythm, subtle developmental changes in its spectral peak, frequency range, and scalp topography are revealed. This mu rhythm further indicates a significant correlation to the crawling onset while powers from other frequency bands do not show such correlations. These details of developmental changes about the mu rhythm provide an insight of rapid changes in the human motor cortex in the first year of life. Our results are consistent with previous findings about the peak frequency shifting of the mu rhythm and further depict detailed developmental curves of its frequency ranges and spatial topographies. The infant mu rhythm could potentially be used to assess motor brain deficiencies at early ages and to evaluate intervention effectiveness in children with neuromotor disorders.

  3. Comparison of a single-channel EEG sleep study to polysomnography.

    PubMed

    Lucey, Brendan P; Mcleland, Jennifer S; Toedebusch, Cristina D; Boyd, Jill; Morris, John C; Landsness, Eric C; Yamada, Kelvin; Holtzman, David M

    2016-12-01

    An accurate home sleep study to assess electroencephalography (EEG)-based sleep stages and EEG power would be advantageous for both clinical and research purposes, such as for longitudinal studies measuring changes in sleep stages over time. The purpose of this study was to compare sleep scoring of a single-channel EEG recorded simultaneously on the forehead against attended polysomnography. Participants were recruited from both a clinical sleep centre and a longitudinal research study investigating cognitively normal ageing and Alzheimer's disease. Analysis for overall epoch-by-epoch agreement found strong and substantial agreement between the single-channel EEG compared to polysomnography (κ = 0.67). Slow wave activity in the frontal regions was also similar when comparing the single-channel EEG device to polysomnography. As expected, Stage N1 showed poor agreement (sensitivity 0.2) due to lack of occipital electrodes. Other sleep parameters, such as sleep latency and rapid eye movement (REM) onset latency, had decreased agreement. Participants with disrupted sleep consolidation, such as from obstructive sleep apnea, also had poor agreement. We suspect that disagreement in sleep parameters between the single-channel EEG and polysomnography is due partially to altered waveform morphology and/or poorer signal quality in the single-channel derivation. Our results show that single-channel EEG provides comparable results to polysomnography in assessing REM, combined Stages N2 and N3 sleep and several other parameters, including frontal slow wave activity. The data establish that single-channel EEG can be a useful research tool. © 2016 European Sleep Research Society.

  4. Electroencephalography (EEG) in the Study of Equivalence Class Formation. An Explorative Study.

    PubMed

    Arntzen, Erik; Steingrimsdottir, Hanna S

    2017-01-01

    Teaching arbitrary conditional discriminations and testing for derived relations may be essential for understanding changes in cognitive skills. Such conditional discrimination procedures are often used within stimulus equivalence research. For example, the participant is taught AB and BC relations and tested if emergent relations as BA, CB, AC and CA occur. The purpose of the current explorative experiment was to study stimulus equivalence class formation in older adults with electroencephalography (EEG) recordings as an additional measure. The EEG was used to learn about whether there was an indication of cognitive changes such as those observed in neurocognitive disorders (NCD). The present study included four participants who did conditional discrimination training and testing. The experimental design employed pre-class formation sorting and post-class formation sorting of the stimuli used in the experiment. EEG recordings were conducted before training, after training and after testing. The results showed that two participants formed equivalence classes, one participant failed in one of the three test relations, and one participant failed in two of the three test relations. This fourth participant also failed to sort the stimuli in accordance with the experimenter-defined stimulus equivalence classes during post-class formation sorting. The EEG indicated no cognitive decline in the first three participants but possible mild cognitive impairment (MCI) in the fourth participant. The results suggest that equivalence class formation may provide information about cognitive impairments such as those that are likely to occur in the early stages of NCD. The study recommends replications with broader samples.

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

    PubMed Central

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

    2015-01-01

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

  6. The Effect of Residing Altitude on Levels of High-Density Lipoprotein Cholesterol: A Pilot Study From the Omani Arab Population.

    PubMed

    Al Riyami, Nafila B; Banerjee, Yajnavalka; Al-Waili, Khalid; Rizvi, Syed G; Al-Yahyaee, Said; Hassan, Mohammed O; Albarwani, Sulayma; Al-Rasadi, Khalid; Bayoumi, Riad A

    2015-07-01

    Lower mortality rates from coronary heart disease and higher levels of serum high-density lipoprotein cholesterol (HDL-C) have been observed in populations residing at high altitude. However, this effect has not been investigated in Arab populations, which exhibit considerable genetic homogeneity. We assessed the relationship between residing altitude and HDL-C in 2 genetically similar Omani Arab populations residing at different altitudes. The association between the levels of HDL-C and other metabolic parameters was also investigated. The levels of HDL-C were significantly higher in the high-altitude group compared with the low-altitude group. Stepwise regression analysis showed that altitude was the most significant factor affecting HDL-C, followed by gender, serum triglycerides, and finally the 2-hour postprandial plasma glucose. This finding is consistent with previously published studies from other populations and should be taken into consideration when comparing cardiovascular risk factors in populations residing at different altitudes.

  7. Neural Mechanisms of Cognitive Dissonance (Revised): An EEG Study

    PubMed Central

    Nikulin, Vadim V.; Blagovechtchenski, Evgeny

    2017-01-01

    Cognitive dissonance theory suggests that our preferences are modulated by the mere act of choosing. A choice between two similarly valued alternatives creates psychological tension (cognitive dissonance) that is reduced by a postdecisional reevaluation of the alternatives. We measured EEG of human subjects during rest and free-choice paradigm. Our study demonstrates that choices associated with stronger cognitive dissonance trigger a larger negative frontocentral evoked response similar to error-related negativity, which has in turn been implicated in general performance monitoring. Furthermore, the amplitude of the evoked response is correlated with the reevaluation of the alternatives. We also found a link between individual neural dynamics (long-range temporal correlations) of the frontocentral cortices during rest and follow-up neural and behavioral effects of cognitive dissonance. Individuals with stronger resting-state long-range temporal correlations demonstrated a greater postdecisional reevaluation of the alternatives and larger evoked brain responses associated with stronger cognitive dissonance. Thus, our results suggest that cognitive dissonance is reflected in both resting-state and choice-related activity of the prefrontal cortex as part of the general performance-monitoring circuitry. SIGNIFICANCE STATEMENT Contrary to traditional decision theory, behavioral studies repeatedly demonstrate that our preferences are modulated by the mere act of choosing. Difficult choices generate psychological (cognitive) dissonance, which is reduced by the postdecisional devaluation of unchosen options. We found that decisions associated with a higher level of cognitive dissonance elicited a stronger negative frontocentral deflection that peaked ∼60 ms after the response. This activity shares similar spatial and temporal features as error-related negativity, the electrophysiological correlate of performance monitoring. Furthermore, the frontocentral resting

  8. Neural Mechanisms of Cognitive Dissonance (Revised): An EEG Study.

    PubMed

    Colosio, Marco; Shestakova, Anna; Nikulin, Vadim V; Blagovechtchenski, Evgeny; Klucharev, Vasily

    2017-05-17

    Cognitive dissonance theory suggests that our preferences are modulated by the mere act of choosing. A choice between two similarly valued alternatives creates psychological tension (cognitive dissonance) that is reduced by a postdecisional reevaluation of the alternatives. We measured EEG of human subjects during rest and free-choice paradigm. Our study demonstrates that choices associated with stronger cognitive dissonance trigger a larger negative frontocentral evoked response similar to error-related negativity, which has in turn been implicated in general performance monitoring. Furthermore, the amplitude of the evoked response is correlated with the reevaluation of the alternatives. We also found a link between individual neural dynamics (long-range temporal correlations) of the frontocentral cortices during rest and follow-up neural and behavioral effects of cognitive dissonance. Individuals with stronger resting-state long-range temporal correlations demonstrated a greater postdecisional reevaluation of the alternatives and larger evoked brain responses associated with stronger cognitive dissonance. Thus, our results suggest that cognitive dissonance is reflected in both resting-state and choice-related activity of the prefrontal cortex as part of the general performance-monitoring circuitry.SIGNIFICANCE STATEMENT Contrary to traditional decision theory, behavioral studies repeatedly demonstrate that our preferences are modulated by the mere act of choosing. Difficult choices generate psychological (cognitive) dissonance, which is reduced by the postdecisional devaluation of unchosen options. We found that decisions associated with a higher level of cognitive dissonance elicited a stronger negative frontocentral deflection that peaked ∼60 ms after the response. This activity shares similar spatial and temporal features as error-related negativity, the electrophysiological correlate of performance monitoring. Furthermore, the frontocentral resting

  9. Aerodynamic Focusing Of High-Density Aerosols

    SciTech Connect

    Ruiz, D. E.; Fisch, Nathaniel

    2014-02-24

    High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1 m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

  10. EEG-fMRI Bayesian framework for neural activity estimation: a simulation study

    NASA Astrophysics Data System (ADS)

    Croce, Pierpaolo; Basti, Alessio; Marzetti, Laura; Zappasodi, Filippo; Del Gratta, Cosimo

    2016-12-01

    Objective. Due to the complementary nature of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), and given the possibility of simultaneous acquisition, the joint data analysis can afford a better understanding of the underlying neural activity estimation. In this simulation study we want to show the benefit of the joint EEG-fMRI neural activity estimation in a Bayesian framework. Approach. We built a dynamic Bayesian framework in order to perform joint EEG-fMRI neural activity time course estimation. The neural activity is originated by a given brain area and detected by means of both measurement techniques. We have chosen a resting state neural activity situation to address the worst case in terms of the signal-to-noise ratio. To infer information by EEG and fMRI concurrently we used a tool belonging to the sequential Monte Carlo (SMC) methods: the particle filter (PF). Main results. First, despite a high computational cost, we showed the feasibility of such an approach. Second, we obtained an improvement in neural activity reconstruction when using both EEG and fMRI measurements. Significance. The proposed simulation shows the improvements in neural activity reconstruction with EEG-fMRI simultaneous data. The application of such an approach to real data allows a better comprehension of the neural dynamics.

  11. Detecting large-scale networks in the human brain using high-density electroencephalography.

    PubMed

    Liu, Quanying; Farahibozorg, Seyedehrezvan; Porcaro, Camillo; Wenderoth, Nicole; Mantini, Dante

    2017-09-01

    High-density electroencephalography (hdEEG) is an emerging brain imaging technique that can be used to investigate fast dynamics of electrical activity in the healthy and the diseased human brain. Its applications are however currently limited by a number of methodological issues, among which the difficulty in obtaining accurate source localizations. In particular, these issues have so far prevented EEG studies from reporting brain networks similar to those previously detected by functional magnetic resonance imaging (fMRI). Here, we report for the first time a robust detection of brain networks from resting state (256-channel) hdEEG recordings. Specifically, we obtained 14 networks previously described in fMRI studies by means of realistic 12-layer head models and exact low-resolution brain electromagnetic tomography (eLORETA) source localization, together with independent component analysis (ICA) for functional connectivity analysis. Our analyses revealed three important methodological aspects. First, brain network reconstruction can be improved by performing source localization using the gray matter as source space, instead of the whole brain. Second, conducting EEG connectivity analyses in individual space rather than on concatenated datasets may be preferable, as it permits to incorporate realistic information on head modeling and electrode positioning. Third, the use of a wide frequency band leads to an unbiased and generally accurate reconstruction of several network maps, whereas filtering data in a narrow frequency band may enhance the detection of specific networks and penalize that of others. We hope that our methodological work will contribute to rise of hdEEG as a powerful tool for brain research. Hum Brain Mapp 38:4631-4643, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. EEG interhemispheric correlation after callosotomy: one case study.

    PubMed

    Corsi-Cabrera, M; Trías, G; Guevara, M A; Haro, R; Hernández, A

    1995-04-01

    High interhemispheric EEG correlation (INTERr) or coherence has been interpreted as a consequence of callosal interconnections. The EEG of a callosotomized (two anterior thirds) 32-yr.-old patient was recorded during relaxed wakefulness with eyes closed. 100 2-sec. artifact-free epochs were digitally filtered into traditional broad bands and INTERr was calculated by means of Pearson product-moment coefficients. INTERr between anterior regions, where they should be expected, showed very few differences between data of this patient and those of two control groups of healthy persons. Only a few differences were observed between posterior regions where the callosum was intact. These results suggest that the role of the callosum is not crucial for INTERr and that subcortical influences and functional differentiation between hemispheres may be more plausible explanations for INTERr.

  13. Study on EEG power and coherence in patients with mild cognitive impairment during working memory task.

    PubMed

    Jiang, Zheng-yan

    2005-12-01

    To investigate the features of electroencephalography (EEG) power and coherence at rest and during a working memory task of patients with mild cognitive impairment (MCI). Thirty-five patients (17 males, 18 females; 52-71 years old) and 34 sex- and age-matched controls (17 males, 17 females; 51-63 years old) were recruited in the present study. Mini-Mental State Examination (MMSE) of 35 patients with MCI and 34 normal controls revealed that the scores of MCI patients did not differ significantly from those of normal controls (P>0.05). Then, EEGs at rest and during working memory task with three levels of working memory load were recorded. The EEG power was computed over 10 channels: right and left frontal (F3, F4), central (C3, C4), parietal (P3, P4), temporal (T5, T6) and occipital (O1, O2); inter-hemispheric coherences were computed from five electrode pairs of F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 for delta (1.0-3.5 Hz), theta (4.0-7.5 Hz), alpha-1 (8.0-10.0 Hz), alpha-2 (10.5 -13.0 Hz), beta-1 (13.5-18.0 Hz) and beta-2 (18.5-30.0 Hz) frequency bands. All values of the EEG power of MCI patients were found to be higher than those of normal controls at rest and during working memory tasks. Furthermore, the values of EEG power in the theta, alpha-1, alpha-2 and beta-1 bands of patients with MCI were significantly high (P<0.05) in comparison with those of normal controls. Correlation analysis indicated a significant negative correlation between the EEG powers and MMSE scores. In addition, during working memory tasks, the EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group (P<0.05). However, there was no significant difference in EEG coherences between two groups at rest. These findings comprise evidence that MCI patients have higher EEG power at rest, and higher EEG power and coherence during working conditions. It suggests that MCI may be associated with compensatory processes at rest and during working

  14. High-density electroencephalography developmental neurophysiological trajectories.

    PubMed

    Dan, Bernard; Pelc, Karine; Cebolla, Ana M; Cheron, Guy

    2015-04-01

    Efforts to document early changes in the developing brain have resulted in the construction of increasingly accurate structural images based on magnetic resonance imaging (MRI) in newborn infants. Tractography diagrams obtained through diffusion tensor imaging have focused on white matter microstructure, with particular emphasis on neuronal connectivity at the level of fibre tract systems. Electroencephalography (EEG) provides a complementary approach with more direct access to brain electrical activity. Its temporal resolution is excellent, and its spatial resolution can be enhanced to physiologically relevant levels, through the combination of high-density recordings (e.g. by using 64 channels in newborn infants) and mathematical models (e.g. inverse modelling computation), to identify generators of different oscillation bands and synchrony patterns. The integration of functional and structural topography of the neonatal brain provides insights into typical brain organization, and the deviations seen in particular contexts, for example the effect of hypoxic-ischaemic insult in terms of damage, eventual reorganization, and functional changes. Endophenotypes can then be used for pathophysiological reasoning, management planning, and outcome measurements, and allow a longitudinal approach to individual developmental trajectories.

  15. Association between the triglyceride to high-density lipoprotein cholesterol ratio and insulin resistance in Korean adolescents: a nationwide population-based study.

    PubMed

    Park, Jae-Min; Lee, Jee-Yon; Dong, Jae June; Lee, Duk-Chul; Lee, Yong-Jae

    2016-11-01

    Studies have suggested the triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) as a surrogate marker of insulin resistance. However, few studies have examined the association between TG/HDL-C and insulin resistance in the general adolescent population. This study aimed to examine the association between TG/HDL-C and insulin resistance in a nationally representative sample of Korean adolescents. A total of 2649 participants aged 12-18 years were selected from the 2007 to 2010 Korean National Health and Nutrition Examination Survey (KNHANES). Insulin resistance was defined as the homeostatic model assessment of insulin resistance (HOMA-IR) values greater than the 80th percentile. The mean values of most cardiometabolic variables increased proportionally with TG/HDL-C quartiles. Compared to individuals in the lowest TG/HDL-C quartile, the odds ratio for insulin resistance for individuals in the highest quartile was 2.91 in boys and 2.38 in girls after adjusting for confounding variables. This study suggests that TG/HDL-C could be a convenient marker for identifying Korean adolescents with insulin resistance.

  16. Time-varying coupling of EEG oscillations predicts excitability fluctuations in the primary motor cortex as reflected by motor evoked potentials amplitude: an EEG-TMS study.

    PubMed

    Ferreri, Florinda; Vecchio, Fabrizio; Ponzo, David; Pasqualetti, Patrizio; Rossini, Paolo Maria

    2014-05-01

    Motor evoked potentials (MEPs) elicited by a train of consecutive, individual transcranial magnetic stimuli demonstrate fluctuations in amplitude with respect to time when recorded from a relaxed muscle. The influence of time-varying, instantaneous modifications of the electroencephalography (EEG) properties immediately preceding the transcranial magnetic stimulation (TMS) has rarely been explored. The aim of this study was to investigate the influence of the pre-TMS motor cortex and related areas EEG profile on time variants of the MEPs amplitude. MRI-navigated TMS and multichannel TMS-compatible EEG devices were used. For each experimental subject, post-hoc analysis of the MEPs amplitude that was based on the 50th percentile of the MEPs amplitude distribution provided two subgroups corresponding to "high" (large amplitude) and "low" (small amplitude). The pre-stimulus EEG characteristics (coherence and spectral profile) from the motor cortex and related areas were analyzed separately for the "high" and "low" MEPs and were then compared. On the stimulated hemisphere, EEG coupling was observed more often in the high compared to the low MEP trials. Moreover, a paradigmatic pattern in which TMS was able to lead to significantly larger MEPs was found when the EEG of the stimulated motor cortex was coupled in the beta 2 band with the ipsilateral prefrontal cortex and in the delta band with the bilateral centro-parietal-occipital cortices. This data provide evidence for a statistically significant influence of time-varying and spatially patterned synchronization of EEG rhythms in determining cortical excitability, namely motor cortex excitability in response to TMS. Copyright © 2013 Wiley Periodicals, Inc.

  17. To study the incidence, etiology and EEG profile of neonatal seizures: a prospective observational study from India.

    PubMed

    Ghanshyambhai, Padmani; Sharma, Deepak; Patel, Ankur; Shastri, Sweta

    2016-01-01

    To study the incidence, etiology and electroencephalography (EEG) profile of neonatal seizures and also to study the correlation between clinical picture and EEG appearance. Prospective observational cohort study. Study duration: September 2011 to April 2013. Inclusion and exclusion: Seizures within first 28 d of life and seizures documented by doctors. Neonates admitted in intensive care unit: intramural (4412) and extramural (1900) admissions (all together 6312). One hundred and seventy-two neonates with seizures were enrolled. All the neonates were evaluated with necessary investigation, ultrasound head and CT scan. All the neonates underwent EEG as early as possible with neonatal stabilization. The etiology of neonatal seizures, CT scan and ultrasound head, characteristic of the EEG and neonatal mortality were noted. The incidence of neonatal seizure was 0.77% in the intramural and 7.3% among the extramural neonates. The incidence of seizures in term newborn was 0.7% and in preterm was 1.1%. The most common cause of neonatal seizure was hypoxic ischemic encephalopathy (HIE) followed by hypocalcemia. The predominant seizure type was multifocal (51%) followed by subtle seizure (43%). There was an EEG abnormality in 72% of the total EEG with varied patterns. The mortality rate in the cohort was 15% with HIE being the most common cause. Most common cases of neonatal seizure were HIE and with the most common type being multifocal. EEG was abnormal in the majority of the neonates with various pattern of abnormality.

  18. High Density Diffusion-Free Nanowell Arrays

    PubMed Central

    Takulapalli, Bharath R; Qiu, Ji; Magee, D. Mitchell; Kahn, Peter; Brunner, Al; Barker, Kristi; Means, Steven; Miersch, Shane; Bian, Xiaofang; Mendoza, Alex; Festa, Fernanda; Syal, Karan; Park, Jin; LaBaer, Joshua; Wiktor, Peter

    2012-01-01

    Proteomics aspires to elucidate the functions of all proteins. Protein microarrays provide an important step by enabling high-throughput studies of displayed proteins. However, many functional assays of proteins include untethered intermediates or products, which could frustrate the use of planar arrays at very high densities because of diffusion to neighboring features. The nucleic acid programmable protein array (NAPPA), is a robust, in situ synthesis method for producing functional proteins just-in-time, which includes steps with diffusible intermediates. We determined that diffusion of expressed proteins led to cross-binding at neighboring spots at very high densities with reduced inter-spot spacing. To address this limitation, we have developed an innovative platform using photolithographically-etched discrete silicon nanowells and used NAPPA as a test case. This arrested protein diffusion and cross-binding. We present confined high density protein expression and display, as well as functional protein-protein interactions, in 8,000 nanowell arrays. This is the highest density of individual proteins in nano-vessels demonstrated on a single slide. We further present proof of principle results on ultra-high density protein arrays capable of up to 24,000 nanowells on a single slide. PMID:22742968

  19. The early electroclinical manifestations of infantile spasms: A video EEG study

    PubMed Central

    Iype, Mary; Kunju, Puthuvathra Abdul Mohammed; Saradakutty, Geetha; Mohan, Devi; Khan, Shahanaz Ahamed Mohammed

    2016-01-01

    Purpose: Infantile spasms are described as flexor extensor and mixed; but more features of their semiology and ictal electroencephalography (EEG) changes are sparse in the literature. The purpose of the study was to describe the clinical and ictal video-EEG characteristics of consecutive cases with infantile spasms and to try to find an association with the etiology. Materials and Methods: The clinical phenomenology and EEG characteristics on video-EEG were analyzed in 16 babies with infantile spasms. Results: A total of 869 spasms were reviewed. Nine (56.3%) showed focal seizures at least once during the recording and 1 (6.3%) had multifocal myoclonus in addition to the spasms. The duration of the cluster and interval between spasms was totally variable in all patients. Lateralizing phenomena were present in at least some of the spasms in all patients. Unilateral manual automatism in the form of holding the pinna was noted in three patients following the spasm. The ictal EEG activity in the majority (75%) was the slow wave. Four (25%) showed fast generalized spindle-like ictal discharges. Spikes, spike and wave activity, or electrodecremental pattern alone during the ictus was seen in none. On bivariate analysis, no factor noted on the video EEG had association with the etiology. Conclusion: Infantile spasms could be associated with focal and other seizures, has unique, non-uniform and variable semiology from patient to patient. The ictal EEG manifestation in the majority (75%) of our patients was the slow wave transient with 25% showing generalized fast spindle-like activity. PMID:27011629

  20. High-density microelectrode array recordings and real-time spike sorting for closed-loop experiments: an emerging technology to study neural plasticity.

    PubMed

    Franke, Felix; Jäckel, David; Dragas, Jelena; Müller, Jan; Radivojevic, Milos; Bakkum, Douglas; Hierlemann, Andreas

    2012-01-01

    Understanding plasticity of neural networks is a key to comprehending their development and function. A powerful technique to study neural plasticity includes recording and control of pre- and post-synaptic neural activity, e.g., by using simultaneous intracellular recording and stimulation of several neurons. Intracellular recording is, however, a demanding technique and has its limitations in that only a small number of neurons can be stimulated and recorded from at the same time. Extracellular techniques offer the possibility to simultaneously record from larger numbers of neurons with relative ease, at the expenses of increased efforts to sort out single neuronal activities from the recorded mixture, which is a time consuming and error prone step, referred to as spike sorting. In this mini-review, we describe recent technological developments in two separate fields, namely CMOS-based high-density microelectrode arrays, which also allow for extracellular stimulation of neurons, and real-time spike sorting. We argue that these techniques, when combined, will provide a powerful tool to study plasticity in neural networks consisting of several thousand neurons in vitro.

  1. Canonical Decomposition of Ictal Scalp EEG and Accurate Source Localisation: Principles and Simulation Study

    PubMed Central

    De Vos, Maarten; De Lathauwer, Lieven; Vanrumste, Bart; Van Huffel, Sabine; Van Paesschen, W.

    2007-01-01

    Long-term electroencephalographic (EEG) recordings are important in the presurgical evaluation of refractory partial epilepsy for the delineation of the ictal onset zones. In this paper, we introduce a new concept for an automatic, fast, and objective localisation of the ictal onset zone in ictal EEG recordings. Canonical decomposition of ictal EEG decomposes the EEG in atoms. One or more atoms are related to the seizure activity. A single dipole was then fitted to model the potential distribution of each epileptic atom. In this study, we performed a simulation study in order to estimate the dipole localisation error. Ictal dipole localisation was very accurate, even at low signal-to-noise ratios, was not affected by seizure activity frequency or frequency changes, and was minimally affected by the waveform and depth of the ictal onset zone location. Ictal dipole localisation error using 21 electrodes was around 10.0 mm and improved more than tenfold in the range of 0.5–1.0 mm using 148 channels. In conclusion, our simulation study of canonical decomposition of ictal scalp EEG allowed a robust and accurate localisation of the ictal onset zone. PMID:18301715

  2. High-density digital recording

    NASA Technical Reports Server (NTRS)

    Kalil, F. (Editor); Buschman, A. (Editor)

    1985-01-01

    The problems associated with high-density digital recording (HDDR) are discussed. Five independent users of HDDR systems and their problems, solutions, and insights are provided as guidance for other users of HDDR systems. Various pulse code modulation coding techniques are reviewed. An introduction to error detection and correction head optimization theory and perpendicular recording are provided. Competitive tape recorder manufacturers apply all of the above theories and techniques and present their offerings. The methodology used by the HDDR Users Subcommittee of THIC to evaluate parallel HDDR systems is presented.

  3. Fine mapping and association studies of a high-density lipoprotein cholesterol linkage region on chromosome 16 in French-Canadian subjects.

    PubMed

    Dastani, Zari; Pajukanta, Päivi; Marcil, Michel; Rudzicz, Nicholas; Ruel, Isabelle; Bailey, Swneke D; Lee, Jenny C; Lemire, Mathieu; Faith, Janet; Platko, Jill; Rioux, John; Hudson, Thomas J; Gaudet, Daniel; Engert, James C; Genest, Jacques

    2010-03-01

    Low levels of high-density lipoprotein cholesterol (HDL-C) are an independent risk factor for cardiovascular disease. To identify novel genetic variants that contribute to HDL-C, we performed genome-wide scans and quantitative association studies in two study samples: a Quebec-wide study consisting of 11 multigenerational families and a study of 61 families from the Saguenay-Lac St-Jean (SLSJ) region of Quebec. The heritability of HDL-C in these study samples was 0.73 and 0.49, respectively. Variance components linkage methods identified a LOD score of 2.61 at 98 cM near the marker D16S515 in Quebec-wide families and an LOD score of 2.96 at 86 cM near the marker D16S2624 in SLSJ families. In the Quebec-wide sample, four families showed segregation over a 25.5-cM (18 Mb) region, which was further reduced to 6.6 Mb with additional markers. The coding regions of all genes within this region were sequenced. A missense variant in CHST6 segregated in four families and, with additional families, we observed a P value of 0.015 for this variant. However, an association study of this single-nucleotide polymorphism (SNP) in unrelated Quebec-wide samples was not significant. We also identified an SNP (rs11646677) in the same region, which was significantly associated with a low HDL-C (P=0.016) in the SLSJ study sample. In addition, RT-PCR results from cultured cells showed a significant difference in the expression of CHST6 and KIAA1576, another gene in the region. Our data constitute additional evidence for a locus on chromosome 16q23-24 that affects HDL-C levels in two independent French-Canadian studies.

  4. Externally and internally controlled attention in infants: an EEG study.

    PubMed

    Stroganova, T A; Orekhova, E V; Posikera, I N

    1998-11-01

    This work was designed to investigate EEG indices of Internally and Externally Controlled Attention in infancy. EEG was recorded in 15 infants aged 7-8 months under three experimental conditions: (1) visual attention to a new stimulation (Externally Controlled Attention or baseline condition); (2) attention guided by internal cognitive schemata during 'anticipatory' phase of the peek-a-boo game (Internally Controlled Attention); and (3) 'reappearance' phase of the peek-a-boo game when the experimenter talked and smiled to an infant (reappearance). The relative power (RP) in 4-5 single-Hz theta sub-band increased under both phases of the peek-a-boo game. The reactive changes of 4-5 single-Hz RP at prefrontal and frontal leads under the Internally Controlled Attention condition positively correlated with the total time during which an infant was able to maintain ICA. The RP in 5-6 single-Hz theta sub-band significantly increased only under the Internally Controlled Attention condition and did not correlate with the total time of this type of attention. The results support the concept of 'Diffuse Theta-Response System' that is active during expectancy and effortfully focused attention. In contrast to theta, the RP in 6-7, 7-8, and 8-9 single-Hz bands decreased during both phases of the game. The decrease was maximal at precentral leads and most probably reflected blockage of the sensorimotor (mu) rhythm due to higher motility and muscular tension in the game situation. It is concluded that EEG is an adequate vehicle for investigation of brain mechanisms of attention and voluntary control in infants.

  5. Effect of serial infusions of reconstituted high-density lipoprotein (CER-001) on coronary atherosclerosis: rationale and design of the CARAT study

    PubMed Central

    Andrews, Jordan; Janssan, Alex; Nguyen, Tracy; Pisaniello, Anthony D.; Scherer, Daniel J.; Kastelein, John J. P.; Merkely, Bela; Nissen, Steven E.; Ray, Kausik; Schwartz, Gregory G.; Worthley, Stephen G.; Keyserling, Connie; Dasseux, Jean-Louis; Butters, Julie; Girardi, Jacinta; Miller, Rosemary

    2017-01-01

    Background High-density lipoprotein (HDL) is believed to have atheroprotective properties, but an effective HDL-based therapy remains elusive. Early studies have suggested that infusion of reconstituted HDL promotes reverse cholesterol transport and vascular reactivity. The CER-001 Atherosclerosis Regression Acute Coronary Syndrome Trial (CARAT) is investigating the impact of infusing an engineered pre-beta HDL mimetic containing sphingomyelin (SM) and dipalmitoyl phosphatidlyglycerol (CER-001) on coronary atheroma volume in patients with a recent acute coronary syndrome (ACS). Methods The CARAT is a phase 2, multicenter trial in which 292 patients with an ACS undergoing intracoronary ultrasonography and showing percent atheroma volume (PAV) greater than 30% are randomly assigned to treatment with ten infusions of CER-001 3 mg/kg or matching placebo, administered at weekly intervals. Intracoronary ultrasonography is repeated at the end of the treatment period. Results The primary endpoint is the nominal change in PAV. Safety and tolerability will also be evaluated. Conclusions CARAT will establish whether serial 3 mg/kg infusions of an engineered pre-beta HDL mimetic containing SM and dipalmitoyl phosphatidlyglycerol (CER-001) will regress atherosclerotic plaque in patients with a recent ACS. PMID:28164012

  6. Anti-TNFα therapy transiently improves high density lipoprotein cholesterol levels and microvascular endothelial function in patients with rheumatoid arthritis: a Pilot Study

    PubMed Central

    2012-01-01

    Background Rheumatoid arthritis (RA) is associated with increased morbidity and mortality from cardiovascular disease (CVD). This can be only partially attributed to traditional CVD risk factors such as dyslipidaemia and their downstream effects on endothelial function. The most common lipid abnormality in RA is reduced levels of high-density lipoprotein (HDL) cholesterol, probably due to active inflammation. In this longitudinal study we hypothesised that anti-tumor necrosis factor-α (anti-TNFα) therapy in patients with active RA improves HDL cholesterol, microvascular and macrovascular endothelial function. Methods Twenty-three RA patients starting on anti-TNFα treatment were assessed for HDL cholesterol level, and endothelial-dependent and -independent function of microvessels and macrovessels at baseline, 2-weeks and 3 months of treatment. Results Disease activity (CRP, fibrinogen, DAS28) significantly decreased during the follow-up period. There was an increase in HDL cholesterol levels at 2 weeks (p < 0.05) which was paralleled by a significant increase in microvascular endothelial-dependent function (p < 0.05). However, both parameters returned towards baseline at 12 weeks. Conclusion Anti-TNFα therapy in RA patients appears to be accompanied by transient but significant improvements in HDL cholesterol levels, which coexists with an improvement in microvascular endothelial-dependent function. PMID:22824166

  7. Serum non-high-density lipoprotein cholesterol levels and the incidence of ischemic stroke in a Japanese population: the Jichi Medical School cohort study.

    PubMed

    Kakehi, Eiichi; Kotani, Kazuhiko; Ishikawa, Shizukiyo; Gotoh, Tadao; Kayaba, Kazunori; Nakamura, Yosikazu; Kajii, Eiji

    2015-03-01

    The predictive value of serum non-high-density lipoprotein cholesterol (non-HDL-C) levels for the incidence of ischemic stroke and its subtypes has not yet been established. The present cohort study investigated their relationships in a Japanese population. The first incidence of ischemic stroke and its subtypes was documented as the primary outcome. A total of 249 ischemic stroke patients (men/women = 145/104) were identified during a follow-up period of 10.7 years among 10 760 community-dwelling subjects (men/women = 4212/6548). Cox proportional hazard model analyses revealed that when compared with the lowest tertile of non-HDL-C, multivariate-adjusted hazard ratios for the highest tertile were 0.55 (95% confidence interval = 0.32-0.95, P = .03) on ischemic stroke and 0.29 (95% confidence interval = 0.08-1.05, P = .06) on cardioembolic infarction in women. Men did not show such significant relationships. Low serum non-HDL-C levels may be a predictive marker associated with an increase in the incidence of ischemic stroke and possibly of cardioembolic infarction in Japanese women.

  8. Sensitivity of the Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) to Topographic Effects: A Case Study in High-Density Cypress Forest

    PubMed Central

    Matsushita, Bunkei; Yang, Wei; Chen, Jin; Onda, Yuyichi; Qiu, Guoyu

    2007-01-01

    Vegetation indices play an important role in monitoring variations in vegetation. The Enhanced Vegetation Index (EVI) proposed by the MODIS Land Discipline Group and the Normalized Difference Vegetation Index (NDVI) are both global-based vegetation indices aimed at providing consistent spatial and temporal information regarding global vegetation. However, many environmental factors such as atmospheric conditions and soil background may produce errors in these indices. The topographic effect is another very important factor, especially when the indices are used in areas of rough terrain. In this paper, we theoretically analyzed differences in the topographic effect on the EVI and the NDVI based on a non-Lambertian model and two airborne-based images acquired from a mountainous area covered by high-density Japanese cypress plantation were used as a case study. The results indicate that the soil adjustment factor “L” in the EVI makes it more sensitive to topographic conditions than is the NDVI. Based on these results, we strongly recommend that the topographic effect should be removed in the reflectance data before the EVI was calculated—as well as from other vegetation indices that similarly include a term without a band ratio format (e.g., the PVI and SAVI)—when these indices are used in the area of rough terrain, where the topographic effect on the vegetation indices having only a band ratio format (e.g., the NDVI) can usually be ignored.

  9. Electroencephalography (EEG) in the Study of Equivalence Class Formation. An Explorative Study

    PubMed Central

    Arntzen, Erik; Steingrimsdottir, Hanna S.

    2017-01-01

    Teaching arbitrary conditional discriminations and testing for derived relations may be essential for understanding changes in cognitive skills. Such conditional discrimination procedures are often used within stimulus equivalence research. For example, the participant is taught AB and BC relations and tested if emergent relations as BA, CB, AC and CA occur. The purpose of the current explorative experiment was to study stimulus equivalence class formation in older adults with electroencephalography (EEG) recordings as an additional measure. The EEG was used to learn about whether there was an indication of cognitive changes such as those observed in neurocognitive disorders (NCD). The present study included four participants who did conditional discrimination training and testing. The experimental design employed pre-class formation sorting and post-class formation sorting of the stimuli used in the experiment. EEG recordings were conducted before training, after training and after testing. The results showed that two participants formed equivalence classes, one participant failed in one of the three test relations, and one participant failed in two of the three test relations. This fourth participant also failed to sort the stimuli in accordance with the experimenter-defined stimulus equivalence classes during post-class formation sorting. The EEG indicated no cognitive decline in the first three participants but possible mild cognitive impairment (MCI) in the fourth participant. The results suggest that equivalence class formation may provide information about cognitive impairments such as those that are likely to occur in the early stages of NCD. The study recommends replications with broader samples. PMID:28377704

  10. The prevalence of seizures in comatose children in the pediatric intensive care unit: a prospective video-EEG study.

    PubMed

    Shahwan, Amre; Bailey, Catherine; Shekerdemian, Lara; Harvey, A Simon

    2010-07-01

    Studies in adult and neonatal intensive care units (ICUs) report a high prevalence of epileptic seizures in comatose patients. The prevalence of seizures in pediatric ICUs is variably reported in a few retrospective studies using different electroencephalography (EEG) methods. We aimed to determine prospectively the prevalence of epileptic seizures (clinical and subclinical) in comatose children in the pediatric ICU using continuous video-EEG (v-EEG) monitoring. We performed v-EEG in consecutive children aged 2 months to 17 years admitted to the pediatric ICU with sustained depressed consciousness over a period of 15 months. We monitored 100 comatose children, 69% within 24 h of ICU admission. Median length of ICU stay was 5 days. Median duration of v-EEG was 20 h. Epileptic seizures were identified in only seven patients, of whom six had a history of epilepsy with witnessed seizures immediately prior to v-EEG. All epileptic seizures were recorded in the first 3 h of v-EEG. Seizures were suspected by ICU staff in 18 monitored patients, only four of whom had confirmed epileptic seizures. The lower prevalence of epileptic seizures and the shorter length of ICU stay in children compared to adults and neonates suggest a different spectrum of disease and neurologic response. Short-duration v-EEG in patients with a history of prior seizures, epilepsy, or clinical events suspected to be seizures seems more appropriate than routine v-EEG in all comatose children in the pediatric ICU.

  11. Continuous Video EEG Monitoring for Electrographic Seizure Diagnosis in Neonates: A Single Center Study

    PubMed Central

    Wietstock, SO; Bonifacio, SL; Sullivan, JE; Nash, KB; Glass, HC

    2015-01-01

    The objective of this study was to determine the diagnostic yield of continuous video-electroencephalography (cEEG) monitoring in critically ill neonates in the setting of a novel, university-based Neonatal Neurocritical Care Service. Patient demographic characteristics, indication for seizure monitoring, and presence of electrographic seizures were obtained by chart review. Among 595 patients cared for by the Neonatal Neurocritical Care Service, 400 (67%) received cEEG. The median duration of cEEG monitoring was 49 (IQR: 22 to 87) hours. Electrographic seizures were captured in 105/400 (26% of monitored patients) and of those, 25/105 (24%) had no clinical correlate. In addition, 52/400 subjects (13%) were monitored due to paroxysmal events concerning for seizures, but never had electrographic seizures. cEEG monitoring helped confirm or rule out ongoing seizures in more than one third of the cases. This finding helps to support the use of cEEG in critically ill neonates. PMID:26129976

  12. Default Mode Network alterations in alexithymia: an EEG power spectra and connectivity study

    PubMed Central

    Imperatori, Claudio; Della Marca, Giacomo; Brunetti, Riccardo; Carbone, Giuseppe Alessio; Massullo, Chiara; Valenti, Enrico Maria; Amoroso, Noemi; Maestoso, Giulia; Contardi, Anna; Farina, Benedetto

    2016-01-01

    Recent neuroimaging studies have shown that alexithymia is characterized by functional alterations in different brain areas [e.g., posterior cingulate cortex (PCC)], during emotional/social tasks. However, only few data are available about alexithymic cortical networking features during resting state (RS). We have investigated the modifications of electroencephalographic (EEG) power spectra and EEG functional connectivity in the default mode network (DMN) in subjects with alexithymia. Eighteen subjects with alexithymia and eighteen subjects without alexithymia matched for age and gender were enrolled. EEG was recorded during 5 min of RS. EEG analyses were conducted by means of the exact Low Resolution Electric Tomography software (eLORETA). Compared to controls, alexithymic subjects showed a decrease of alpha power in the right PCC. In the connectivity analysis, compared to controls, alexithymic subjects showed a decrease of alpha connectivity between: (i) right anterior cingulate cortex and right PCC, (ii) right frontal lobe and right PCC, and (iii) right parietal lobe and right temporal lobe. Finally, mediation models showed that the association between alexithymia and EEG connectivity values was directed and was not mediated by psychopathology severity. Taken together, our results could reflect the neurophysiological substrate of some core features of alexithymia, such as the impairment in emotional awareness. PMID:27845326

  13. Antiepileptic drug intervention decouples electroencephalogram (EEG) signals: a case study in Unverricht-Lundborg Disease.

    PubMed

    Liu, Chang-Chia; Xanthopoulos, Petros; Chaovalitwongse, W; Pardalos, Panos M; Uthman, Basim M

    2008-01-01

    Change in severity of myoclonus as an outcome measure of antiepileptic drug (AED) treatment in patients with Unverricht-Lundborg Disease (ULD) has been estimated by utilizing the Unified Myoclonus Rating Scale (UMRS). In this study, we measure treatment effects through EEG analysis using mutual information approach to quantify interdependence/coupling strength among different electrode sites. Mutual information is known to have the ability to capture linear and non-linear dependencies between EEG time series with superior performance over the traditional linear measures. One subject with ULD participated in this study and 1-hour EEG recordings were acquired before and after treatment of AED. Our results indicate that the mutual information is significantly lower after taking the add-on AED for four weeks at least. This finding could lead to a new insight for developing a new outcome measure for patient with ULD, when UMRS could potentially fail to detect a significant difference.

  14. Neural Differences between Covert and Overt Attention Studied using EEG with Simultaneous Remote Eye Tracking

    PubMed Central

    Kulke, Louisa V.; Atkinson, Janette; Braddick, Oliver

    2016-01-01

    Research on neural mechanisms of attention has generally instructed subjects to direct attention covertly while maintaining a fixed gaze. This study combined simultaneous eye tracking and electroencephalogram (EEG) to measure neural attention responses during exogenous cueing in overt attention shifts (with saccadic eye movements to a target) and compared these with covert attention shifts (responding manually while maintaining central fixation). EEG analysis of the period preceding the saccade latency showed similar occipital response amplitudes for overt and covert shifts, although response latencies differed. However, a frontal positivity was greater during covert attention shifts, possibly reflecting saccade inhibition to maintain fixation. The results show that combined EEG and eye tracking can be successfully used to study natural overt shifts of attention (applicable to non-verbal infants) and that requiring inhibition of saccades can lead to additional frontal responses. Such data can be used to refine current neural models of attention that have been mainly based on covert shifts. PMID:27932962

  15. Human memory retention and recall processes. A review of EEG and fMRI studies.

    PubMed

    Amin, Hafeezullah; Malik, Aamir S

    2013-10-01

    Human memory is an important concept in cognitive psychology and neuroscience. Our brain is actively engaged in functions of learning and memorization. Generally, human memory has been classified into 2 groups: short-term/working memory, and long-term memory. Using different memory paradigms and brain mapping techniques, psychologists and neuroscientists have identified 3 memory processes: encoding, retention, and recall. These processes have been studied using EEG and functional MRI (fMRI) in cognitive and neuroscience research. This study reviews previous research reported for human memory processes, particularly brain behavior in memory retention and recall processes with the use of EEG and fMRI. We discuss issues and challenges related to memory research with EEG and fMRI techniques.

  16. Impact of the Triglycerides to High-Density Lipoprotein Cholesterol Ratio on the Incidence and Progression of CKD: A Longitudinal Study in a Large Japanese Population.

    PubMed

    Tsuruya, Kazuhiko; Yoshida, Hisako; Nagata, Masaharu; Kitazono, Takanari; Iseki, Kunitoshi; Iseki, Chiho; Fujimoto, Shouichi; Konta, Tsuneo; Moriyama, Toshiki; Yamagata, Kunihiro; Narita, Ichiei; Kimura, Kenjiro; Kondo, Masahide; Asahi, Koichi; Kurahashi, Issei; Ohashi, Yasuo; Watanabe, Tsuyoshi

    2015-12-01

    The impact of the triglycerides to high-density lipoprotein cholesterol (TG:HDL-C) ratio on chronic kidney disease (CKD) is unclear. Longitudinal cohort study. 124,700 participants aged 39 to 74 years in the Japanese Specific Health Check and Guidance System, including 50,392 men, 74,308 women, 102,900 without CKD, and 21,800 with CKD. Quartiles of TG:HDL-C ratio. Changes in estimated glomerular filtration rate (eGFR) and urinary protein excretion during the 2-year study period. Incident CKD in participants without CKD, and progression of CKD in participants with CKD. In the entire study population, higher quartile of TG:HDL-C ratio at baseline was significantly associated with greater decline in eGFR and increase in urinary protein excretion during the 2-year study period, even after adjustment for confounding factors. A higher ratio was associated with higher risk of incident CKD in participants without CKD and higher risk of rapid decline in eGFR and increase in urinary protein excretion in participants with CKD. Higher TG:HDL-C ratio was more strongly associated with decline in eGFR (P for interaction = 0.002) and with incident CKD (P for interaction = 0.05) in participants with diabetes than without diabetes. Short observation period and single measurement of all variables. A higher TG:HDL-C ratio affects the decline in eGFR and incidence and progression of CKD in the Japanese population. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  17. Genome-wide linkage scan for plasma high density lipoprotein cholesterol, apolipoprotein A-1 and triglyceride variation among American Indian populations: the Strong Heart Family Study

    PubMed Central

    Li, X; Monda, KL.; Göring, HHH; Haack, K; Cole, SA; Diego, VP; Almasy, L; Laston, S; Howard, BV; Shara, NM; Lee, ET; Best, LG; Fabsitz, RR; MacCluer, JW; North, KE

    2011-01-01

    Background Recent studies have identified chromosomal regions linked to variation in high density lipoprotein cholesterol (HDL-C), apolipoprotein A-1 (Apo A-1) and triglyceride (TG), although results have been inconsistent and previous studies of American Indian populations are limited Objective In an attempt to localize quantitative trait loci (QTLs) influencing HDL-C, Apo A-1 and TG, we conducted genome-wide linkage scans of subjects of the Strong Heart Family Study. Methods We implemented analyses in 3484 men and women aged 18 years or older, at three study centers. Results With adjustment for age, sex and center, we detected a QTL influencing both HDL-C (LOD = 4.4, genome-wide P = 0.001) and Apo A-1 (LOD = 3.2, genome-wide P = 0.020) nearest marker D6S289 at 6p23 in the Arizona sample. Another QTL influencing Apo A-1 was found nearest marker D9S287 at 9q22.2 (LOD = 3.0, genome-wide P = 0.033) in the North and South Dakotas. We detected a QTL influencing TG nearest marker D15S153 at 15q22.31 (LOD = 4.5 in the overall sample and LOD = 3.8 in the Dakotas sample, genome-wide P = 0.0044) and when additionally adjusted for waist, current smoking, current alcohol, current estrogen, lipid treatment, impaired fasting glucose, and diabetes, nearest marker D10S217 at 10q26.2 (LOD = 3.7, genome-wide P = 0.0058) in the Arizona population. Conclusions The replication of QTLs in regions of the genome that harbor well-known candidate genes suggest that chromosomes 6p, 9q and 15q warrant further investigation with fine mapping for causative polymorphisms in American Indians. PMID:19429595

  18. Association of Air Pollution Exposures With High-Density Lipoprotein Cholesterol and Particle Number: The Multi-Ethnic Study of Atherosclerosis.

    PubMed

    Bell, Griffith; Mora, Samia; Greenland, Philip; Tsai, Michael; Gill, Ed; Kaufman, Joel D

    2017-05-01

    The relationship between air pollution and cardiovascular disease may be explained by changes in high-density lipoprotein (HDL). We examined the cross-sectional relationship between air pollution and both HDL cholesterol and HDL particle number in the MESA Air study (Multi-Ethnic Study of Atherosclerosis Air Pollution). Study participants were 6654 white, black, Hispanic, and Chinese men and women aged 45 to 84 years. We estimated individual residential ambient fine particulate pollution exposure (PM2.5) and black carbon concentrations using a fine-scale likelihood-based spatiotemporal model and cohort-specific monitoring. Exposure periods were averaged to 12 months, 3 months, and 2 weeks prior to examination. HDL cholesterol and HDL particle number were measured in the year 2000 using the cholesterol oxidase method and nuclear magnetic resonance spectroscopy, respectively. We used multivariable linear regression to examine the relationship between air pollution exposure and HDL measures. A 0.7×10(-)(6) m(-)(1) higher exposure to black carbon (a marker of traffic-related pollution) averaged over a 1-year period was significantly associated with a lower HDL cholesterol (-1.68 mg/dL; 95% confidence interval, -2.86 to -0.50) and approached significance with HDL particle number (-0.55 mg/dL; 95% confidence interval, -1.13 to 0.03). In the 3-month averaging time period, a 5 μg/m(3) higher PM2.5 was associated with lower HDL particle number (-0.64 μmol/L; 95% confidence interval, -1.01 to -0.26), but not HDL cholesterol (-0.05 mg/dL; 95% confidence interval, -0.82 to 0.71). These data are consistent with the hypothesis that exposure to air pollution is adversely associated with measures of HDL. © 2017 American Heart Association, Inc.

  19. Primary Low Level of High-Density Lipoprotein Cholesterol and Risks of Coronary Heart Disease, Cardiovascular Disease, and Death: Results From the Multi-Ethnic Study of Atherosclerosis.

    PubMed

    Ahmed, Haitham M; Miller, Michael; Nasir, Khurram; McEvoy, John W; Herrington, David; Blumenthal, Roger S; Blaha, Michael J

    2016-05-15

    Prior studies observing associations between low levels of high-density lipoprotein (HDL) cholesterol and cardiovascular disease (CVD) have often been conducted among persons with metabolic or other lipid abnormalities. In this study, we investigated the association between primary low HDL cholesterol and coronary heart disease (CHD), CVD, and all-cause death after adjustment for confounders in the Multi-Ethnic Study of Atherosclerosis (MESA). Participants who were free of clinical CVD were recruited from 6 US research centers from 2000 to 2002 and followed for a median duration of 10.2 years. We defined "primary low HDL cholesterol" as HDL cholesterol level <40 mg/dL (men) or <50 mg/dL (women), triglyceride level <100 mg/dL, and low-density lipoprotein cholesterol level <100 mg/dL (n = 158). We defined an "optimal" lipid profile as HDL cholesterol ≥40 mg/dL (men) or ≥50 mg/dL (women) and triglycerides and low-density lipoprotein cholesterol <100 mg/dL (n = 780). For participants with primary low HDL cholesterol versus those with an optimal lipid profile, adjusted hazard ratios for total CHD, CVD, and death were 2.25 (95% confidence interval (CI): 1.20, 4.21; P = 0.011), 1.93 (95% CI: 1.11, 3.34; P = 0.020), and 1.11 (95% CI: 0.67, 1.84; P = 0.69), respectively. Participants with primary low HDL cholesterol had higher risks of CHD and CVD than participants with optimal lipid profiles but no difference in survival after a median 10.2 years of follow-up. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Alcohol reduces prefrontal cortical excitability in humans: a combined TMS and EEG study.

    PubMed

    Kähkönen, Seppo; Wilenius, Juha; Nikulin, Vadim V; Ollikainen, Marko; Ilmoniemi, Risto J

    2003-04-01

    The effects of alcohol (0.8 g/kg) on the prefrontal cortex were studied in nine healthy subjects using the technique of transcranial magnetic stimulation (TMS) combined with electroencephalography (EEG). A total of 120 magnetic pulses were delivered with a figure-of-eight coil to the left prefrontal cortex at the rate of 0.4-0.7 Hz. The EEG was recorded simultaneously with 60 scalp electrodes (41 electrodes were used for analysis); the TMS-evoked activation was estimated by the area under the global mean field amplitude (GMFA) time curve. TMS caused changes in EEG activity lasting up to 270 ms poststimulus. Alcohol decreased GMFA at 30-270 ms poststimulus (713+/-303 vs 478+/-142 microV ms; p=0.007). Alcohol-induced differences were most pronounced at anterior electrodes. These results suggest that alcohol reduces the excitability in the prefrontal cortex.

  1. The Reconstruction of Nasal Septal Perforation with High Density Porous Polyethylene Covered with Fascia Lata: An Experimental Study on Rabbit Model

    PubMed Central

    Onar, Vedat; Sayin, Ibrahim; Onol, Suzan Deniz; Aydin, Tamer

    2011-01-01

    Objectives Evaluation of a new material, high-density porous polyethylene (HDPP), which is covered with fascia lata, for experimental nasal septal perforation closure. Methods Twenty New Zealand albino rabbits were included and divided into study and control groups. A lateral incision was made from the lateral aspect of the left nares to the incisura nasomaxillaris. After exposure of the cavum nasi, the nasal mucoperichondrium was elevated bilaterally. A full-thickness 0.5×0.5-cm perforation was created over the septum nasi with a No. 11 surgical blade. A fascia lata graft was used for the study group. The HDPP was covered with fascia lata and placed under the elevated mucosa. HDPP without a fascial covering was used in the control group. Four months after the procedure, magnetic resonance imaging was performed to evaluate resorption of the material. The animals were sacrificed, and the nasal septum was completely removed. Macroscopic and histopathological examinations were performed on the nasal septum. Results All rabbits had survived after the 4-month period. Macroscopically, nine of 10 (90%) perforations were closed in the fascia lata-covered HDPP group. Histopathological examination of these nine rabbits revealed that the continuity of cartilage was disturbed in the perforation areas. Granulation tissue was inverted in areas in which the cartilage continuity was disturbed. The HDPP had remained intact at the edge of the perforation. In the HDPP group, six of 10 implants were still perforated (60%) and four (40%) were closed. The fascia lata-covered HDPP implant had a significantly higher perforation closure rate than that of the HDPP implant alone (P<0.05). Conclusion In cases of septal perforation, it is better to cover the HDPP implant with fascia lata. This covered implant can be used for the repair of nasal septal perforations. HDPP implants are easy to work with and avoid the increased operative time and morbidity associated with harvesting autografts

  2. High-Density Lipoprotein Cholesterol and Objective Measures of Lower Extremity Performance in Older Nondisabled Persons: The InChianti Study

    PubMed Central

    Volpato, Stefano; Ble, Alessandro; Metter, E. Jeffrey; Lauretani, Fulvio; Bandinelli, Stefania; Zuliani, Giovanni; Fellin, Renato; Ferrucci, Luigi; Guralnik, Jack M.

    2009-01-01

    Objectives To evaluate the independent association between high-density lipoprotein cholesterol (HDL-C) levels and objective measures of lower extremity performance. Design Cross-sectional cohort study. Setting Community-based. Participants Eight hundred thirty-six nondisabled women and men aged 65 and older enrolled in the Invecchiare in Chianti study. Mesasurements Lower extremity performance was assessed using 4-m walking speed at fast pace, 400-m walking speed, and knee extension torque. Fasting HDL-C levels were determined using commercial enzymatic tests. Results The mean age of participants was 73.7 (65–92), and 55.6% were women. After adjusting for potential con-founders (sociodemographic factors, smoking, physical activity, body composition, and clinical conditions including cardiovascular and cerebrovascular disease, inflammatory markers, and serum testosterone) HDL-C levels were significantly associated with knee extension torque in men and women and with 4-m and 400-m walking speed in men. Men in the highest tertile of the HDL-C distribution (>55 mg/dL) had, on average, a three times greater probability of belonging to the best tertile of all indexes of lower extremity performance, including 4-m fast walking speed (odds ratio (OR) = 2.57, 95% = confidence interval (CI) = 1.07–6.17), 400-m walking speed (OR = 3.74, 95% CI = 1.20–11.7), and knee extension torque (OR = 3.63, 95% = CI 1.41–9.33). Path analysis suggested a direct relationship between HDL-C and knee extension torque. Conclusion In older nondisabled persons, HDL-C levels are highly correlated with knee extension torque and walking speed. Further research should focus on the biological mechanism of this association. PMID:18205758

  3. Genome wide association study and genomic prediction for fatty acid composition in Chinese Simmental beef cattle using high density SNP array.

    PubMed

    Zhu, Bo; Niu, Hong; Zhang, Wengang; Wang, Zezhao; Liang, Yonghu; Guan, Long; Guo, Peng; Chen, Yan; Zhang, Lupei; Guo, Yong; Ni, Heming; Gao, Xue; Gao, Huijiang; Xu, Lingyang; Li, Junya

    2017-06-14

    Fatty acid composition of muscle is an important trait contributing to meat quality. Recently, genome-wide association study (GWAS) has been extensively used to explore the molecular mechanism underlying important traits in cattle. In this study, we performed GWAS using high density SNP array to analyze the association between SNPs and fatty acids and evaluated the accuracy of genomic prediction for fatty acids in Chinese Simmental cattle. Using the BayesB method, we identified 35 and 7 regions in Chinese Simmental cattle that displayed significant associations with individual fatty acids and fatty acid groups, respectively. We further obtained several candidate genes which may be involved in fatty acid biosynthesis including elongation of very long chain fatty acids protein 5 (ELOVL5), fatty acid synthase (FASN), caspase 2 (CASP2) and thyroglobulin (TG). Specifically, we obtained strong evidence of association signals for one SNP located at 51.3 Mb for FASN using Genome-wide Rapid Association Mixed Model and Regression-Genomic Control (GRAMMAR-GC) approaches. Also, region-based association test identified multiple SNPs within FASN and ELOVL5 for C14:0. In addition, our result revealed that the effectiveness of genomic prediction for fatty acid composition using BayesB was slightly superior over GBLUP in Chinese Simmental cattle. We identified several significantly associated regions and loci which can be considered as potential candidate markers for genomics-assisted breeding programs. Using multiple methods, our results revealed that FASN and ELOVL5 are associated with fatty acids with strong evidence. Our finding also suggested that it is feasible to perform genomic selection for fatty acids in Chinese Simmental cattle.

  4. Association between non-high-density lipoprotein cholesterol concentrations and mortality from coronary heart disease among Japanese men and women: the Ibaraki Prefectural Health Study.

    PubMed

    Noda, Hiroyuki; Iso, Hiroyasu; Irie, Fujiko; Sairenchi, Toshimi; Ohtaka, Emiko; Ohta, Hitoshi

    2010-02-01

    The aim of this study was to examine whether non-high-density lipoprotein cholesterol (non-HDL-cholesterol) raises the risk of coronary heart disease in a dose-response fashion in a non-obese population with low total cholesterol levels and high HDL-cholesterol levels, such as Japanese. A total of 30,802 men and 60,417 women, aged 40 to 79 years with no history of stroke or coronary heart disease, completed a baseline risk factor survey in 1993 under the auspices of the Ibaraki Prefectural Health Study. Systematic mortality surveillance through 2003 identified 539 coronary heart disease deaths. The mean values for non-HDL-cholesterol were 140 mg/dL for men and 151 mg/dL for women. The corresponding mean values were 193 mg/dL and 208 mg/dL total cholesterol and 52 mg/dL and 57 mg/dL HDL-cholesterol, respectively. Men with non-HDL-cholesterol > or = 180 mg/dL had a two-fold higher age-adjusted risk of mortality from coronary heart disease than did those with non-HDL-cholesterol <100 mg/dL, whereas no such association was found for women. The multivariable hazard ratio for > or = 180 mg/dL versus <100 mg/dL of non-HDL-cholesterol was 2.22 (95% confidence interval: 1.37 to 3.62) for men and 0.71 (0.37 to 1.34) for women. Higher concentrations of non-HDL-cholesterol were associated with an increased risk of mortality from coronary heart disease for men, but not for women.

  5. Spacelab high density digital recorders

    NASA Technical Reports Server (NTRS)

    Blais, R. A.

    1983-01-01

    The design and performance of the high-density digital recorder (HDDR) developed for use at the NASA centers (KSC, JSC, and GSFC) and at the JPL to store and retrieve 50-Mb/s PCM data streams from the Spacelab experiments are reported. The recording reproduction, and transport requirements are reviewed; and the design solutions adopted in the final version of the HDDR are described, incuding three-position-modulation and Y-phase encoding, microprocessor-controlled automatic bit synchronization and equalization, cyclic-redundancy-check error detection and correction, clock regeneration, data and clock variations, tape-speed control, and EEE-488 remote control. Reliable performance, with bit error rates 1 in 10 to the 10th forward and 1 in 10 to the 9th reverse or better and packing density up to 50 percent greater than that obtainable using conventional codes, is reported after 1.5 years of service.

  6. Spacelab high density digital recorders

    NASA Technical Reports Server (NTRS)

    Blais, R. A.

    1983-01-01

    The design and performance of the high-density digital recorder (HDDR) developed for use at the NASA centers (KSC, JSC, and GSFC) and at the JPL to store and retrieve 50-Mb/s PCM data streams from the Spacelab experiments are reported. The recording reproduction, and transport requirements are reviewed; and the design solutions adopted in the final version of the HDDR are described, incuding three-position-modulation and Y-phase encoding, microprocessor-controlled automatic bit synchronization and equalization, cyclic-redundancy-check error detection and correction, clock regeneration, data and clock variations, tape-speed control, and EEE-488 remote control. Reliable performance, with bit error rates 1 in 10 to the 10th forward and 1 in 10 to the 9th reverse or better and packing density up to 50 percent greater than that obtainable using conventional codes, is reported after 1.5 years of service.

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

    ERIC Educational Resources Information Center

    Vocate, Donna R.

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

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

    ERIC Educational Resources Information Center

    Vocate, Donna R.

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

  9. Population structure and genetic basis of the agronomic traits of upland cotton in China revealed by a genome-wide association study using high-density SNPs.

    PubMed

    Huang, Cong; Nie, Xinhui; Shen, Chao; You, Chunyuan; Li, Wu; Zhao, Wenxia; Zhang, Xianlong; Lin, Zhongxu

    2017-03-16

    Gossypium hirsutum L. represents the largest source of textile fibre, and China is one of the largest cotton producing and consuming countries in the world. To investigate the genetic architecture of the agronomic traits of upland cotton in China, a diverse and nation-wide population containing 503 G. hirsutum accessions was collected for a genome-wide association study (GWAS) on 16 agronomic traits. The accessions were planted in four places from 2012 to 2013 for phenotyping. The CottonSNP63K array and a published high-density map based on this array were used for genotyping. The 503 G. hirsutum accessions were divided into 3 subpopulations based on 11,975 quantified polymorphic single-nucleotide polymorphisms (SNPs). By comparing the genetic structure and phenotypic variation among 3 genetic subpopulations, 7 geographic distributions and 4 breeding periods, we found that geographic distribution and breeding period were not the determinants of genetic structure. In addition, no obvious phenotypic differentiations were found among the 3 subpopulations, even though they had different genetic backgrounds. A total of 324 SNPs and 160 candidate quantitative trait loci (QTL) regions were identified as significantly associated with the 16 agronomic traits. A network was established for multi-effects in QTLs and inter-associations among traits. Thirty-eight associated regions had pleiotropic effects controlling more than one trait. One candidate gene, Gh_D08G2376, was speculated to control the lint percentage (LP). This GWAS is the first report using high-resolution SNPs in upland cotton in China to comprehensively investigate agronomic traits, and it provides a fundamental resource for cotton genetic research and breeding. This article is protected by copyright. All rights reserved.

  10. Triglycerides and non-high-density lipoprotein cholesterol and the incidence of cardiovascular disease in an urban Japanese cohort: the Suita study.

    PubMed

    Okamura, Tomonori; Kokubo, Yoshihiro; Watanabe, Makoto; Higashiyama, Aya; Ono, Yuu; Miyamoto, Yoshihiro; Yoshimasa, Yasunao; Okayama, Akira

    2010-03-01

    The impact of elevated triglycerides (TG) and non-high density lipoprotein cholesterol (non-HDLC) on the incidence of stroke and myocardial infarction (MI) has not been well evaluated in Asian populations such as in Japan, which have a lower incidence of myocardial infarction, but a higher risk of stroke than Western populations. The authors conducted an 11.7-year prospective study ending in 2005 of 5098 Japanese aged 30-79 living in an urban population, initially free of stroke or MI. The relationship between serum lipids and the risk for stroke and MI was determined by dividing the participants into four groups stratified by the combination of serum levels of TG and non-HDLC. The cut-off value was 1.7mmol/L for TG and 4.9mmol/L for non-HDLC. The total person-years were 59,774 (27,461 for men and 32,313 for women). During the follow-up period, there were 113 cases of MI and 180 of stoke (with 116 cerebral infarctions). Compared with the low TG/low non-HDLC group, the hazard ratio (95% confidence interval) for MI in the high TG/high non-HDLC group was 2.55 (1.53-4.24) after adjustment for other cardiovascular risk factors. The hazard ratio for cerebral infarction in the high TG alone group was 1.63 (1.03-2.56); however, the risk of cerebral infarction was not significantly increased in the other groups. High serum levels of TG and non-HDLC are both important targets for the prevention of cardiovascular disease in Japan.

  11. Method for assessing lead, cadmium, mercury and arsenic in high-density polyethylene packaging and study of the migration into yoghurt and simulant.

    PubMed

    Kiyataka, Paulo Henrique M; Dantas, Sílvia T; Pallone, Juliana Azevedo Lima

    2014-01-01

    The purpose of this paper was to assess the concentration of lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) in high-density polyethylene (HDPE) packaging intended for contact with yoghurt and the migration of these elements using the food itself and 3% acetic acid as a food simulant in accordance to ANVISA, the Brazilian Health Surveillance Agency. In order to perform this study, it was necessary to develop and validate a method by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. For method validation, the parameters linearity, limits of detection (LODs) and quantification (LOQs), accuracy and precision were determined. Fifteen commercial samples of yoghurt, marketed in Campinas - São Paulo (Brazil), were used for the analysis. The packaging and yoghurt were digested in high-pressure ashing equipment (HPA) and the migration of the elements into simulant were determined directly in the solution. The validated method proved adequate and the results obtained showed that all the packaging had levels of Hg and Cd below the LOQ, corresponding to 1.0 and 1.5 μg l(-1), respectively. The highest levels of As and Pb were 0.87 and 462.3 mg kg(-1), respectively. The migration of these elements to the yoghurt after 45 days of contact at 4ºC was below the LOQ for all the samples assessed. The results of specific migration into 3% acetic acid simulant showed the concentrations of Cd, Hg and As below 5, 5 and 10 µg kg(-1), respectively, which are the maximum limits set by ANVISA. However, for three samples the packaging lid showed migration of Pb into simulant ranging from 30.6 to 40.2 μg kg(-1), exceeding the limit set by ANVISA of 10 μg kg(-1).

  12. Spectroscopic and microscopic studies of self-assembled nc-Si/a-SiC thin films grown by low pressure high density spontaneous plasma processing.

    PubMed

    Das, Debajyoti; Kar, Debjit

    2014-12-14

    In view of suitable applications in the window layer of nc-Si p-i-n solar cells in superstrate configuration, the growth of nc-Si/a-SiC composite films was studied, considering the trade-off relation between individual characteristics of its a-SiC component to provide a wide optical-gap and electrically conducting nc-Si component to simultaneously retain enough crystalline linkages to facilitate proper crystallization to the i-nc-Si absorber-layer during its subsequent growth. Self-assembled nc-Si/a-SiC thin films were spontaneously grown by low-pressure planar inductively coupled plasma CVD, operating in electromagnetic mode, providing high atomic-H density. Spectroscopic simulations of ellipsometry and Raman data, and systematic chemical and structural analysis by XPS, TEM, SEM and AFM were performed. Corresponding to optimized inclusion of C essentially incorporated as Si-C bonds in the network, the optical-gap of the a-SiC component widened, void fraction including the incubation layer thickness reduced. While the bulk crystallinity decreased only marginally, Si-ncs diminished in size with narrower distribution and increased number density. With enhanced C-incorporation, formation of C-C bonds in abundance deteriorates the Si continuous bonding network and persuades growth of an amorphous dominated silicon-carbon heterostructure containing high-density tiny Si-ncs. Stimulated nanocrystallization identified in the Si-network, induced by a limited amount of carbon incorporation, makes the material most suitable for applications in nc-Si solar cells. The novelty of the present work is to enable spontaneous growth of self-assembled superior quality nc-Si/a-SiC thin films and simultaneous spectroscopic simulation-based optimization of properties for utilization in devices.

  13. Doctor-diagnosed health problems in a region with a high density of concentrated animal feeding operations: a cross-sectional study.

    PubMed

    Hooiveld, Mariëtte; Smit, Lidwien A M; van der Sman-de Beer, Femke; Wouters, Inge M; van Dijk, Christel E; Spreeuwenberg, Peter; Heederik, Dick J J; Yzermans, C Joris

    2016-02-17

    There is growing interest in health risks of residents living near concentrated animal feeding operations (CAFOs). Previous research mostly focused on swine CAFOs and self-reported respiratory conditions. The aim was to study the association between the presence of swine, poultry, cattle and goat CAFOs and health of Dutch neighbouring residents using electronic medical records from general practitioners (GPs). Data for the year 2009 were collected of 119,036 inhabitants of a rural region with a high density of CAFOs using information from GIAB (high exposed population). A comparison was made with GP data from 78,060 inhabitants of rural areas with low densities of CAFOs (low exposed population). Associations between the number of CAFOs near residents' homes and morbidity were determined by multilevel (cross-classified) logistic regression. In 2009, the prevalence of most respiratory and gastrointestinal conditions was similar in the high and low exposed population. Exceptions were pneumonia, atopic eczema and unspecified infectious diseases with an increased prevalence, and sinusitis with a decreased prevalence in the high exposed population. Within the high CAFO density region, the number of poultry, cattle and swine CAFOs near residents' homes was not associated with allergic, respiratory or gastrointestinal conditions. Conversely, each additional goat CAFO within the postal code area of residents' homes significantly increased the odds of unspecified infectious disease and pneumonia by 87 and 41 percent, respectively. Using GP records, pneumonia and unspecified infectious diseases were positively associated with the number of goat CAFOs near residents' homes, but no association was found between swine, cattle, and poultry CAFOs and respiratory, allergic or gastrointestinal conditions.

  14. Association of high-density lipoprotein cholesterol concentration with different types of stroke and coronary heart disease: The Japan Public Health Center-based prospective (JPHC) study.

    PubMed

    Saito, Isao; Yamagishi, Kazumasa; Kokubo, Yoshihiro; Yatsuya, Hiroshi; Iso, Hiroyasu; Sawada, Norie; Inoue, Manami; Tsugane, Shoichiro

    2017-10-01

    Although low high-density lipoprotein (HDL) cholesterol concentration is an established risk factor for coronary heart disease (CHD), information regarding subtypes of stroke is very limited, especially in Asian populations. A prospective study was conducted among 30,736 individuals aged 40-69 years, who lived in nine communities in Japan and did not have a history of cardiovascular disease (CVD). CHD and stroke, including its subtypes, were assessed, and sex-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for outcomes were estimated according to quintiles of HDL cholesterol using Cox proportional models adjusted for other CVD risk factors. We identified 296 CHD and 1712 stroke events over a median 15 yr of follow-up. HDL cholesterol concentration showed an inverse association with CHD in men and women. A low HDL cholesterol concentration slightly raised the risk for total strokes in men, but not in women. When analyzed by subtypes, we observed an inverse relationship between HDL cholesterol concentration and the incidence of lacunar infarction, with an adjusted HR for the lowest quintile of HDL cholesterol concentration compared with the highest quintile of 1.63 (95% CI, 1.00-2.66) in men and 1.97 (95% CI, 1.19-3.26) in women. HDL cholesterol concentration was positively associated with the risk of intracerebral hemorrhage (ICH) in a linear manner in women (p for trend = 0.028), but not in men. The associations of HDL cholesterol concentration with lacunar infarction and ICH may be related to different functional properties of HDL rather than to its protective function against lipid-rich atherosclerosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Non-high-density lipoprotein cholesterol and the development of coronary heart disease and stroke subtypes in a general Japanese population: the Hisayama Study.

    PubMed

    Imamura, Tsuyoshi; Doi, Yasufumi; Ninomiya, Toshiharu; Hata, Jun; Nagata, Masaharu; Ikeda, Fumie; Mukai, Naoko; Hirakawa, Yoichiro; Yoshida, Daigo; Fukuhara, Masayo; Kitazono, Takanari; Kiyohara, Yutaka

    2014-04-01

    It has not been fully determined whether non-high-density lipoprotein cholesterol (non-HDLC) levels are involved in vascular events, especially stroke, in general Asian populations. We evaluated the association between non-HDLC levels and the risk of type-specific cardiovascular disease in a prospective cohort study in Japan. A total of 2452 community-dwelling Japanese subjects aged≥40 years were followed prospectively for 24 years. The age- and sex-adjusted incidence of coronary heart diseases (CHD) significantly increased with elevating non-HDLC levels (P for trend<0.001), but no such association was observed for ischemic and hemorrhagic strokes. With regard to ischemic stroke subtypes, the age- and sex-adjusted incidence of lacunar infarction significantly increased with elevating non-HDLC levels (P for trend<0.01), and such tendency was seen for atherothrombotic infarction (P for trend=0.098), while a significant inverse association was observed for cardioembolic infarction (P for trend=0.007). After adjustment for confounders, namely, age, sex, diabetes, body mass index, systolic blood pressure, electrocardiogram abnormalities, current drinking, current smoking, and regular exercise, the associations remained significant for CHD [adjusted hazard ratio (HR) for a 1 standard deviation of non-HDLC concentrations=1.17, 95% confidence interval (CI)=1.02 to 1.35], atherothrombotic infarction (adjusted HR=1.39, 95% CI=1.09 to 1.79), and cardioembolic infarction (adjusted HR=0.64, 95% CI=0.47 to 0.85). Our findings suggest that elevated non-HDLC levels are a significant risk factor for the development of atherothrombotic infarction as well as CHD but reduce the risk of cardioembolic infarction in the general Japanese population. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Possible association of ABCB1:c.3435T>C polymorphism with high-density-lipoprotein-cholesterol response to statin treatment--a pilot study.

    PubMed

    Sałacka, Anna; Bińczak-Kuleta, Agnieszka; Kaczmarczyk, Mariusz; Hornowska, Iwona; Safranow, Krzysztof; Clark, Jeremy S C

    2014-08-14

    The gene product ABCB1 (formerly MDR1 or P-glycoprotein) is hypothesized to be involved in cholesterol cellular trafficking, redistribution and intestinal re-absorption. Carriers of the ABCB1:3435T allele have previously been associated with decreases in ABCB1 mRNA and protein concentrations and have been correlated with changes in serum lipid concentrations. The aim of this study was to investigate possible association between the ABCB1:3435T>C polymorphism and changes in lipids in patients following statin treatment. Outpatients (n=130) were examined: 43 men (33%), 87 women (67%): treated with atorvastatin or simvastatin (all patients with equivalent dose of 20 or 40 mg/d simvastatin). Blood was taken for ABCB1:3435T>C genotyping, and before and after statin treatment for lipid concentration determination (total cholesterol, high-density-lipoprotein-cholesterol (HDL-C), triglycerides). Change (Δ) in lipid parameters, calculated as differences between measurements before and after treatment, were analyzed with multiple regression adjustments: gender, diabetes, age, body mass index, equivalent statin dose, length of treatment. Univariate and multivariate analyses showed significant differences in ΔHDL-C (univariate p=0.029; multivariate p=0.036) and %ΔHDL-C (univariate p=0.021; multivariate p=0.023) between patients with TT (-0.05 ± 0.13 g/l; -6.8% ± 20%; respectively) and CC+CT genotypes (0.004 ± 0.15 g/l; 4.1 ± 26%; respectively). Reduction of HDL-C in homozygous ABCB1:3435TT patients suggests this genotype could be associated with a reduction in the benefits of statin treatment.

  17. Pain Ratings, Psychological Functioning and Quantitative EEG in a Controlled Study of Chronic Back Pain Patients

    PubMed Central

    Schmidt, Stefan; Naranjo, José Raúl; Brenneisen, Christina; Gundlach, Julian; Schultz, Claudia; Kaube, Holger; Hinterberger, Thilo; Jeanmonod, Daniel

    2012-01-01

    Objectives Several recent studies report the presence of a specific EEG pattern named Thalamocortical Dysrhythmia (TCD) in patients with severe chronic neurogenic pain. This is of major interest since so far no neuroscientific indicator of chronic pain could be identified. We investigated whether a TCD-like pattern could be found in patients with moderate chronic back pain, and we compared patients with neuropathic and non-neuropathic pain components. We furthermore assessed the presence of psychopathology and the degree of psychological functioning and examined whether the strength of the TCD-related EEG markers is correlated with psychological symptoms and pain ratings. Design Controlled clinical trial with age and sex matched healthy controls. Methods Spontaneous EEG was recorded in 37 back pain patients and 37 healthy controls. Results We were not able to observe a statistically significant TCD effect in the EEG data of the whole patient group, but a subsample of patients with evidence for root damage showed a trend in this direction. Pain patients showed markedly increased psychopathology. In addition, patients' ratings of pain intensity within the last 1 to 12 months showed strong correlations with EEG power, while psychopathology was correlated to the peak frequency. Conclusion Out of several possible interpretations the most likely conclusion is that only patients with severe pain as well as root lesions with consecutive thalamic deafferentation develop the typical TCD pattern. Our primary method of defining ‘neuropathic pain’ could not reliably determine if such a deafferentation was present. Nevertheless the analysis of a specific subsample as well as correlations between pain ratings, psychopathology and EEG power and peak frequency give some support to the TCD concept. Trial Registration ClinicalTrials.gov NCT00744575 PMID:22431961

  18. An experimental study to investigate the effects of a motion tracking electromagnetic sensor during EEG data acquisition.

    PubMed

    Bashashati, Ali; Noureddin, Borna; Ward, Rabab K; Lawrence, Peter D; Birch, Gary E

    2006-03-01

    A power spectral analysis study was conducted to investigate the effects of using an electromagnetic motion tracking sensor on an electroencephalogram (EEG) recording system. The results showed that the sensors do not generate any consistent frequency component(s) in the power spectrum of the EEG in the frequencies of interest (0.1-55 Hz).

  19. Psychophysiological classification and experiment study for spontaneous EEG based on two novel mental tasks.

    PubMed

    Wang, Hui; Song, Aiguo; Li, Bowei; Xu, Baoguo; Li, Yangming

    2015-01-01

    Study of imagination offers a perfect setting for study of a large variety of states of consciousness. Here, we studied the characteristics of two electroencephalographic (EEG) patterns evoked by two different imaginary tasks and evaluated the binary classification performance. Fifteen individuals (11 male and 4 female, age range of 22 to 33) participated in five sessions of 32-channel EEG recordings. Only by analyzing the subjects' output EEG signals from the central parieto-occipital region of PZ electrode, under the circumstances of consciousness of relaxation-meditation or tension-imagination, we carried out the experiment of feature extraction for spontaneous EEG, as the subjects were blindfolded but asked to open their eyes all the same. The Hilbert-Huang Transform (HHT) was utilized to obtain the Hilbert time-frequency amplitude spectrum, and then with the feature vector set extracted, a two-class Fisher linear discriminant analysis classifier was trained for classification of data epochs of those two tasks. The overall result was that about 90% (± 5%) of the epochs could be correctly classified to their originating task. This study not only brings new opportunities for consciousness studies, but also provides a new classification paradigm for achieving control of robots based on the brain-computer interface (BCI).

  20. Estimating a neutral reference for electroencephalographic recordings: the importance of using a high-density montage and a realistic head model

    NASA Astrophysics Data System (ADS)

    Liu, Quanying; Balsters, Joshua H.; Baechinger, Marc; van der Groen, Onno; Wenderoth, Nicole; Mantini, Dante

    2015-10-01

    Objective. In electroencephalography (EEG) measurements, the signal of each recording electrode is contrasted with a reference electrode or a combination of electrodes. The estimation of a neutral reference is a long-standing issue in EEG data analysis, which has motivated the proposal of different re-referencing methods, among which linked-mastoid re-referencing (LMR), average re-referencing (AR) and reference electrode standardization technique (REST). In this study we quantitatively assessed the extent to which the use of a high-density montage and a realistic head model can impact on the optimal estimation of a neutral reference for EEG recordings. Approach. Using simulated recordings generated by projecting specific source activity over the sensors, we assessed to what extent AR, REST and LMR may distort the scalp topography. We examined the impact electrode coverage has on AR and REST, and how accurate the REST reconstruction is for realistic and less realistic (three-layer and single-layer spherical) head models, and with possible uncertainty in the electrode positions. We assessed LMR, AR and REST also in the presence of typical EEG artifacts that are mixed in the recordings. Finally, we applied them to real EEG data collected in a target detection experiment to corroborate our findings on simulated data. Main results. Both AR and REST have relatively low reconstruction errors compared to LMR, and that REST is less sensitive than AR and LMR to artifacts mixed in the EEG data. For both AR and REST, high electrode density yields low re-referencing reconstruction errors. A realistic head model is critical for REST, leading to a more accurate estimate of a neutral reference compared to spherical head models. With a low-density montage, REST shows a more reliable reconstruction than AR either with a realistic or a three-layer spherical head model. Conversely, with a high-density montage AR yields better results unless precise information on electrode positions

  1. Estimating a neutral reference for electroencephalographic recordings: the importance of using a high-density montage and a realistic head model.

    PubMed

    Liu, Quanying; Balsters, Joshua H; Baechinger, Marc; van der Groen, Onno; Wenderoth, Nicole; Mantini, Dante

    2015-10-01

    In electroencephalography (EEG) measurements, the signal of each recording electrode is contrasted with a reference electrode or a combination of electrodes. The estimation of a neutral reference is a long-standing issue in EEG data analysis, which has motivated the proposal of different re-referencing methods, among which linked-mastoid re-referencing (LMR), average re-referencing (AR) and reference electrode standardization technique (REST). In this study we quantitatively assessed the extent to which the use of a high-density montage and a realistic head model can impact on the optimal estimation of a neutral reference for EEG recordings. Using simulated recordings generated by projecting specific source activity over the sensors, we assessed to what extent AR, REST and LMR may distort the scalp topography. We examined the impact electrode coverage has on AR and REST, and how accurate the REST reconstruction is for realistic and less realistic (three-layer and single-layer spherical) head models, and with possible uncertainty in the electrode positions. We assessed LMR, AR and REST also in the presence of typical EEG artifacts that are mixed in the recordings. Finally, we applied them to real EEG data collected in a target detection experiment to corroborate our findings on simulated data. Both AR and REST have relatively low reconstruction errors compared to LMR, and that REST is less sensitive than AR and LMR to artifacts mixed in the EEG data. For both AR and REST, high electrode density yields low re-referencing reconstruction errors. A realistic head model is critical for REST, leading to a more accurate estimate of a neutral reference compared to spherical head models. With a low-density montage, REST shows a more reliable reconstruction than AR either with a realistic or a three-layer spherical head model. Conversely, with a high-density montage AR yields better results unless precise information on electrode positions is available. Our study is the first

  2. Estimating a neutral reference for electroencephalographic recordings: the importance of using a high-density montage and a realistic head model

    PubMed Central

    Liu, Quanying; Balsters, Joshua H; Baechinger, Marc; van der Groen, Onno; Wenderoth, Nicole; Mantini, Dante

    2015-01-01

    Abstract Objective. In electroencephalography (EEG) measurements, the signal of each recording electrode is contrasted with a reference electrode or a combination of electrodes. The estimation of a neutral reference is a long-standing issue in EEG data analysis, which has motivated the proposal of different re-referencing methods, among which linked-mastoid re-referencing (LMR), average re-referencing (AR) and reference electrode standardization technique (REST). In this study we quantitatively assessed the extent to which the use of a high-density montage and a realistic head model can impact on the optimal estimation of a neutral reference for EEG recordings. Approach. Using simulated recordings generated by projecting specific source activity over the sensors, we assessed to what extent AR, REST and LMR may distort the scalp topography. We examined the impact electrode coverage has on AR and REST, and how accurate the REST reconstruction is for realistic and less realistic (three-layer and single-layer spherical) head models, and with possible uncertainty in the electrode positions. We assessed LMR, AR and REST also in the presence of typical EEG artifacts that are mixed in the recordings. Finally, we applied them to real EEG data collected in a target detection experiment to corroborate our findings on simulated data. Main results. Both AR and REST have relatively low reconstruction errors compared to LMR, and that REST is less sensitive than AR and LMR to artifacts mixed in the EEG data. For both AR and REST, high electrode density yields low re-referencing reconstruction errors. A realistic head model is critical for REST, leading to a more accurate estimate of a neutral reference compared to spherical head models. With a low-density montage, REST shows a more reliable reconstruction than AR either with a realistic or a three-layer spherical head model. Conversely, with a high-density montage AR yields better results unless precise information on electrode

  3. Association between hemoglobin and diabetes in relation to the triglycerides-to-high-density lipoprotein cholesterol (TG-HDL) ratio in Japanese individuals: the Nagasaki Islands Study.

    PubMed

    Shimizu, Yuji; Nakazato, Mio; Sekita, Takaharu; Koyamatsu, Jun; Kadota, Koichiro; Yamasaki, Hironori; Goto, Hisashi; Takamura, Noboru; Aoyagi, Kiyoshi; Maeda, Takahiro

    2014-01-01

    Our previous study reported that categorizing diabetes patients according to the serum triglycerides-to-high-density lipoprotein cholesterol (TG-HDL) ratio is useful for estimating the risk of atherosclerosis, as a high TG-HDL ratio in patients with diabetes constitutes risk factors for atherosclerosis. Another study showed that a high hemoglobin level is associated with the risk of atherosclerosis. However, no previous studies have examined the association between the hemoglobin level and diabetes categorized by the TG-HDL ratio. In order to investigate these associations, we conducted a cross-sectional study of 3,733 (1,299 men and 2,434 women) Japanese participants 30-89 years of age undergoing a general health checkup. We investigated the association between the hemoglobin levels and the incidence of diabetes in all subjects, who were divided into tertiles according to the TG-HDL ratio. Diabetes was defined as an HbA1c (NGSP) level of ≥ 6.5% and/or the initiation of glucose-lowering or insulin therapy. Of the 265 diabetes patients identified in this study, 116 had a high TG-HDL ratio (high TG-HDL diabetes) and 71 had a low TG-HDL ratio (low TG-HDL diabetes). Independent from classical cardiovascular risk factors, the multivariate odds ratio of a 1 SD (standard deviation) increment in hemoglobin (1.30 g/dL for men, 1.16 g/dL for women) was 1.04 (95% confidence intervals (CI): 0.88-1.22) for all patients with diabetes, 1.44 (95%CI: 1.17-1.77) for the patients with high TG-HDL diabetes and 0.67 (95%CI: 0.54-0.83) for the patients with low TG-HDL diabetes. The hemoglobin level is positively associated with high TG-HDL diabetes and inversely associated with low TG-HDL diabetes. These findings suggest that measuring the hemoglobin level is clinically relevant for estimating the risk of atherosclerosis in patients with diabetes categorized according to the TG-HDL ratio.

  4. Hemodynamic and EEG Time-Courses During Unilateral Hand Movement in Patients with Cortical Myoclonus. An EEG-fMRI and EEG-TD-fNIRS Study.

    PubMed

    Visani, E; Canafoglia, L; Gilioli, I; Sebastiano, D Rossi; Contarino, V E; Duran, D; Panzica, F; Cubeddu, R; Contini, D; Zucchelli, L; Spinelli, L; Caffini, M; Molteni, E; Bianchi, A M; Cerutti, S; Franceschetti, S; Torricelli, A

    2015-11-01

    Multimodal human brain mapping has been proposed as an integrated approach capable of improving the recognition of the cortical correlates of specific neurological functions. We used simultaneous EEG-fMRI (functional magnetic resonance imaging) and EEG-TD-fNIRS (time domain functional near-infrared spectroscopy) recordings to compare different hemodynamic methods with changes in EEG in ten patients with progressive myoclonic epilepsy and 12 healthy controls. We evaluated O2Hb, HHb and Blood oxygen level-dependent (BOLD) changes and event-related desynchronization/synchronization (ERD/ERS) in the α and β bands of all of the subjects while they performed a simple motor task. The general linear model was used to obtain comparable fMRI and TD-fNIRS activation maps. We also analyzed cortical thickness in order to evaluate any structural changes. In the patients, the TD-NIRS and fMRI data significantly correlated and showed a significant lessening of the increase in O2Hb and the decrease in BOLD. The post-movement β rebound was minimal or absent in patients. Cortical thickness was moderately reduced in the motor area of the patients and correlated with the reduction in the hemodynamic signals. The fMRI and TD-NIRS results were consistent, significantly correlated and showed smaller hemodynamic changes in the patients. This finding may be partially attributable to mild cortical thickening. However, cortical hyperexcitability, which is known to generate myoclonic jerks and probably accounts for the lack of EEG β-ERS, did not reflect any increased energy requirement. We hypothesize that this is due to a loss of inhibitory neuronal components that typically fire at high frequencies.

  5. Extreme high high-density lipoprotein cholesterol is paradoxically associated with high mortality in men and women: two prospective cohort studies.

    PubMed

    Madsen, Christian M; Varbo, Anette; Nordestgaard, Børge G

    2017-08-21

    High-density lipoprotein (HDL) cholesterol concentrations are inversely associated with cardiovascular disease and mortality across a range of concentrations, but genetic evidence suggest that extreme high concentrations may paradoxically lead to more cardiovascular disease. We tested the hypothesis that extreme high concentrations of HDL cholesterol are associated with high all-cause mortality in men and women. A total of 52 268 men and 64 240 women were included from the two prospective population-based studies, the Copenhagen City Heart Study and the Copenhagen General Population Study. During 745 452 person-years of follow-up, number of deaths from any cause were 5619 (mortality rate, 17.1/1000 person-years (95% confidence interval (CI): 16.7-17.6)) in men and 5059 (mortality rate, 12.1/1000 person-years (11.8-12.4)) in women. The association between HDL cholesterol concentrations and all-cause mortality was U-shaped for both men and women, with both extreme high and low concentrations being associated with high all-cause mortality risk. The concentration of HDL cholesterol associated with the lowest all-cause mortality was 1.9 mmol/L (95% CI: 1.4-2.0) (73 mg/dL (54-77)) in men and 2.4 mmol/L (1.8-2.5) (93 mg/dL (69-97)) in women. When compared with the groups with the lowest risk, the multifactorially adjusted hazard ratios for all-cause mortality were 1.36 (95% CI: 1.09-1.70) for men with HDL cholesterol of 2.5-2.99 mmol/L (97-115 mg/dL) and 2.06 (1.44-2.95) for men with HDL cholesterol ≥3.0 mmol/L (116 mg/dL). For women, corresponding hazard ratios were 1.10 (0.83-1.46) for HDL cholesterol of 3.0-3.49 mmol/L (116-134 mg/dL) and 1.68 (1.09-2.58) for HDL cholesterol ≥3.5 mmol/L (135 mg/dL). Men and women in the general population with extreme high HDL cholesterol paradoxically have high all-cause mortality. These findings need confirmation in other studies.

  6. Comparison of Brain Activity during Drawing and Clay Sculpting: A Preliminary qEEG Study

    ERIC Educational Resources Information Center

    Kruk, Kerry A.; Aravich, Paul F.; Deaver, Sarah P.; deBeus, Roger

    2014-01-01

    A preliminary experimental study examined brain wave frequency patterns of female participants (N = 14) engaged in two different art making conditions: clay sculpting and drawing. After controlling for nonspecific effects of movement, quantitative electroencephalographic (qEEG) recordings were made of the bilateral medial frontal cortex and…

  7. Disentangling Neural Sources of the Motor Interference Effect in High Functioning Autism: An EEG-Study

    ERIC Educational Resources Information Center

    Deschrijver, Eliane; Wiersema, Jan R.; Brass, Marcel

    2017-01-01

    The role of imitation in autism spectrum disorder (ASD) is controversial. Researchers have argued that deficient control of self- and other-related motor representations (self-other distinction) might explain imitation difficulties. In a recent EEG study, we showed that control of imitation relies on high-level as well as on low-level cognitive…

  8. Comparison of Brain Activity during Drawing and Clay Sculpting: A Preliminary qEEG Study

    ERIC Educational Resources Information Center

    Kruk, Kerry A.; Aravich, Paul F.; Deaver, Sarah P.; deBeus, Roger

    2014-01-01

    A preliminary experimental study examined brain wave frequency patterns of female participants (N = 14) engaged in two different art making conditions: clay sculpting and drawing. After controlling for nonspecific effects of movement, quantitative electroencephalographic (qEEG) recordings were made of the bilateral medial frontal cortex and…

  9. Altered resting-state EEG complexity in children with Tourette syndrome: A preliminary study.

    PubMed

    Weng, Wen-Chin; Chang, Chi-Feng; Wong, Lee Chin; Lin, Jui-Hsiang; Lee, Wang-Tso; Shieh, Jiann-Shing

    2017-05-01

    Tourette syndrome is a developmental neuropsychiatric disorder in children, and abnormal corticobasal ganglion connectivity is implied for the pathophysiology. Multiscale entropy, an entropy-based method to measure dynamic complexity at multiple temporal scales, is helpful to disclose the information of brain connectivity. This preliminary study investigated the complexity of resting-state electroencephalogram signals using multiscale entropy in children with Tourette syndrome. Resting-state electroencephalographic (EEG) signals were analyzed by sample entropy and multiscale entropy methods in 10 children with Tourette syndrome and 10 healthy gender- and age-matched controls. Except for the Fp2 channel, the complexity index values in all channels were reduced in children with Tourette syndrome compared with those in normal controls. A statistically significant reduction in EEG complexity was found in the bilateral central, parietal, occipital, and left temporal regions, indicating disturbed brain connectivity in Tourette syndrome. Although there was no difference of complexity in the higher frequency spectra, there was a statistically significant difference of complexity in lower frequency in F3 channel, pointing to the importance of examining a range of time scales in exploring EEG signals. Our preliminary study demonstrated that EEG complexity was significantly lower in children with Tourette syndrome than in normal controls. This difference may serve as a marker of disturbed brain connectivity in such individuals and suggests that further clinical studies are warranted. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  10. Hepatitis E Virus: A Cross-Sectional Serological and Virological Study in Pigs and Humans at Zoonotic Risk within a High-Density Pig Farming Area.

    PubMed

    Caruso, C; Peletto, S; Rosamilia, A; Modesto, P; Chiavacci, L; Sona, B; Balsamelli, F; Ghisetti, V; Acutis, P L; Pezzoni, G; Brocchi, E; Vitale, N; Masoero, L

    2016-07-05

    An increase in autochthonous hepatitis E virus (HEV) infections has been recorded in Italy suspected to be zoonotically transmitted from pigs; this study was carried out to determinate the seroprevalence and risk factors associated with hepatitis HEV exposition, both in swine and humans working in pig farms, located within a high-density pig farming area in Piedmont region, north-western Italy. The presence of viral RNA in human and swine samples was also evaluated, and phylogenetic analysis was performed on HEV-positive samples. Forty-two swine farms were sampled; 142 workers were enrolled in the study and classified into two groups: (i) 69 workers with occupational contact with swine (including veterinarians and farmers) recruited in the 42 sampled farms; (ii) 73 without occupational contact with swine. Forty-one of 42 (97%) swine farms resulted positive to enzyme-linked immunosorbent assay test for HEV antibodies (Abs). Overall seroprevalence in swine was 50% (441/879), with seropositivity rate higher in sows (333/469, 71%). HEV RNA in stool samples was detected in animals from 13 of 42 tested farms (31%), and a higher positivity resulted in weaners (40/246, 16.3%). Phylogenetic analysis classified all HEV isolates within genotype 3 (subtypes 3f, 3e, 3c). All humans were negative for HEV viral genome in blood. Five of 142 sera were positive for IgG anti-HEV with an overall prevalence of 3.52% with no statistically significant differences in prevalence rates between workers at zoonotic risk and the control group (5.7% versus 1.3%). In contrast, a significant difference (OR 10.1) was observed within the subgroup including subjects exposed for short periods (veterinarians) compared with those who worked for long periods (farmers) suggesting a correlation between the time of exposure and the likelihood of HEV infection. Reporting HEV infection is not mandatory in Italy, but a constant epidemiological surveillance should be ensured to clarify the epidemiology of this

  11. Preliminary results of residual deficits observed in athletes with concussion history: combined EEG and cognitive study.

    PubMed

    Munia, Tamanna T K; Gendreau, Jeffrey L; Verma, Ajay K; Johnson, Benjamin D; Romanick, Mark; Tavakolian, Kouhyar; Fazel-Rezai, Reza

    2016-08-01

    Assessment, treatment, and management of sport-related concussions are a widely recognized public health issue. Although several neuropsychological and motor assessment tools have been developed and implemented for sports teams at various levels and ages, the sensitivity of these tests has yet to be validated with more objective measures to make return-to-play (RTP) decisions more confidently. The present study sought to analyze the residual effect of concussions on a sample of adolescent athletes who sustained one or more previous concussions compared to those who had no concussion history. For this purpose, a wide variety of assessment tools containing both neurocognitive and electroencephalogram (EEG) elements were used. All clinical testing and EEG were repeated at 8 months, 10 months, and 12 months post-injury for both healthy and concussed athletes. The concussed athletes performed poorer than healthy athletes on processing speed and impulse control subtest of neurocognitive test on month 8, but no alterations were marked in terms of visual and postural stability. EEG analysis revealed significant differences in brain activities of concussed athletes through all three intervals. These long-term neurocognitive and EEG deficits found from this ongoing sport-related concussion study suggest that the post-concussion physiological deficits may last longer than the observed clinical recovery.

  12. A systematic study of head tissue inhomogeneity and anisotropy on EEG forward problem computing.

    PubMed

    Bashar, M R; Li, Y; Wen, P

    2010-03-01

    In this study, we propose a stochastic method to analyze the effects of inhomogeneous anisotropic tissue conductivity on electroencephalogram (EEG) in forward computation. We apply this method to an inhomogeneous and anisotropic spherical human head model. We apply stochastic finite element method based on Legendre polynomials, Karhunen-Loeve expansion and stochastic Galerkin methods. We apply Volume and Wang's constraints to restrict the anisotropic conductivities for both the white matter (WM) and the skull tissue compartments. The EEGs resulting from deterministic and stochastic FEMs are compared using statistical measurement techniques. Based on these comparisons, we find that EEGs generated by incorporating WM and skull inhomogeneous anisotropic tissue properties individually result in an average of 56.5 and 57.5% relative errors, respectively. Incorporating these tissue properties for both layers together generate 43.5% average relative error. Inhomogeneous scalp tissue causes 27% average relative error and a full inhomogeneous anisotropic model brings in an average of 45.5% relative error. The study results demonstrate that the effects of inhomogeneous anisotropic tissue conductivity are significant on EEG.

  13. Prevalence of Sleep-Disordered Breathing During Routine Electroencephalogram (EEG): A Hospital-Based Descriptive Study.

    PubMed

    Poothrikovil, Rajesh P; Al Asmi, Abdullah; Nandhagopal, Ramachandiran; Al Abri, Mohammed

    2017-01-01

    Sleep-disordered breathing (SDB) in adults is a common condition that is associated with a range of medical problems including hypertension, cardiovascular complications, and increase of seizure frequency in susceptible individuals. Polysomnography (PSG) is considered the gold standard measure in the diagnosis of SDB. This is an observational study on the frequency of SDB in adult patients referred for routine EEG. We found that routine EEG was capable of detecting moderate to severe symptoms of SDB in 14% of adult patients (95% confidence interval = 8.1-19.9%). The state of sleep during a routine EEG recording could help in assessing a SDB pattern and could provide an opportunity for further diagnostic sleep consultation if the patient has not previously reported problems with sleep or if SDB was not considered by the referring physician. This study underscores the need for a practice approach to ensure that patients suffering from SDB are properly referred to a sleep specialist. In the context of this report, some training and experience in PSG can be an added advantage for EEG technologists in the detection of SDB.

  14. Plasma Cystatin C and High-Density Lipoprotein Are Important Biomarkers of Alzheimer’s Disease and Vascular Dementia: A Cross-Sectional Study

    PubMed Central

    Wang, Rui; Chen, Zhaoyu; Fu, Yongmei; Wei, Xiaobo; Liao, Jinchi; Liu, Xu; He, Bingjun; Xu, Yunqi; Zou, Jing; Yang, Xiaoyan; Weng, Ruihui; Tan, Sheng; McElroy, Christopher; Jin, Kunlin; Wang, Qing

    2017-01-01

    Objectives: Cystatin C (Cys C) and high-density lipoprotein (HDL) play critical roles in neurodegenerative diseases, such as dementia, Alzheimer’s disease (AD) and vascular dementia (VaD). However, whether they can be used as reliable biomarkers to distinguish patients with dementia from healthy subjects and to determine disease severity remain largely unknown. Methods: We conducted a cross-sectional study to determine plasma Cys C and HDL levels of 88 patients with dementia (43 AD patients, 45 VaD patients) and 45 healthy age-matched controls. The severity of dementia was determined based on the Schwab and England Activities of Daily Living (ADL) Scale, the Mini-mental State Examination (MMSE), the Global Deterioration Scale (GDS), the Lawton Instrumental ADL (IADL) Scale, and the Hachinski Ischemia Scale (Hachinski). Receiver operating characteristic (ROC) curves were calculated to determine the diagnostic accuracy of Cys C and HDL levels in distinguishing patients with dementia from healthy subjects. Results: We found that plasma Cys C levels were higher, but HDL levels were lower in AD and VaD patients respectively, compared to healthy control subjects. Yet, Cys C levels were highest among patients with VaD. Interestingly, plasma Cys C levels were significantly correlated with IADL Scale scores. In addition, the ROC curves for Cys C (area under the curve, AUC 0.816 for AD, AUC 0.841 for VaD) and HDL (AUC 0.800 for AD, AUC 0.731 for VaD) exhibited potential diagnostic value in distinguishing AD/VaD patients from healthy subjects. While the ROC curve for the combination of Cys C and HDL (AUC 0.873 for AD, AUC 0.897 for VaD) showed higher diagnostic accuracy in distinguishing AD/VaD patients from healthy subjects than the separate curves for each parameter. Conclusions: Our findings suggest that the inflammatory mediators Cys C and HDL may play important roles in the pathogenesis of dementia, and plasma Cys C and HDL levels may be useful screening tools for

  15. Plasma Cystatin C and High-Density Lipoprotein Are Important Biomarkers of Alzheimer's Disease and Vascular Dementia: A Cross-Sectional Study.

    PubMed

    Wang, Rui; Chen, Zhaoyu; Fu, Yongmei; Wei, Xiaobo; Liao, Jinchi; Liu, Xu; He, Bingjun; Xu, Yunqi; Zou, Jing; Yang, Xiaoyan; Weng, Ruihui; Tan, Sheng; McElroy, Christopher; Jin, Kunlin; Wang, Qing

    2017-01-01

    Objectives: Cystatin C (Cys C) and high-density lipoprotein (HDL) play critical roles in neurodegenerative diseases, such as dementia, Alzheimer's disease (AD) and vascular dementia (VaD). However, whether they can be used as reliable biomarkers to distinguish patients with dementia from healthy subjects and to determine disease severity remain largely unknown. Methods: We conducted a cross-sectional study to determine plasma Cys C and HDL levels of 88 patients with dementia (43 AD patients, 45 VaD patients) and 45 healthy age-matched controls. The severity of dementia was determined based on the Schwab and England Activities of Daily Living (ADL) Scale, the Mini-mental State Examination (MMSE), the Global Deterioration Scale (GDS), the Lawton Instrumental ADL (IADL) Scale, and the Hachinski Ischemia Scale (Hachinski). Receiver operating characteristic (ROC) curves were calculated to determine the diagnostic accuracy of Cys C and HDL levels in distinguishing patients with dementia from healthy subjects. Results: We found that plasma Cys C levels were higher, but HDL levels were lower in AD and VaD patients respectively, compared to healthy control subjects. Yet, Cys C levels were highest among patients with VaD. Interestingly, plasma Cys C levels were significantly correlated with IADL Scale scores. In addition, the ROC curves for Cys C (area under the curve, AUC 0.816 for AD, AUC 0.841 for VaD) and HDL (AUC 0.800 for AD, AUC 0.731 for VaD) exhibited potential diagnostic value in distinguishing AD/VaD patients from healthy subjects. While the ROC curve for the combination of Cys C and HDL (AUC 0.873 for AD, AUC 0.897 for VaD) showed higher diagnostic accuracy in distinguishing AD/VaD patients from healthy subjects than the separate curves for each parameter. Conclusions: Our findings suggest that the inflammatory mediators Cys C and HDL may play important roles in the pathogenesis of dementia, and plasma Cys C and HDL levels may be useful screening tools for

  16. Non-high-density lipoprotein fractions are strongly associated with the presence of metabolic syndrome independent of obesity and diabetes: a population-based study among Iranian adults.

    PubMed

    Ghodsi, Saeed; Meysamie, Alipasha; Abbasi, Mehrshad; Ghalehtaki, Reza; Esteghamati, Alireza; Malekzadeh, Masoud M; Asgari, Fereshteh; Gouya, Mohammad M

    2017-01-01

    Non-HDL-C as a valuable predictor of premature atherosclerosis, coronary events like first Myocardial infarction and cardiovascular mortality has a high accuracy of measurement both in fasting and non-fasting individuals. Metabolic syndrome (MetS) can promote the development of diabetes mellitus, endothelial dysfunction and atherosclerosis. A common pathway for cross linking of metabolic abnormalities and non-HDL-C has been suggested. In this study we aimed to describe the potential association between non-HDL cholesterol fractions and metabolic syndrome. Data of third national surveillance of the risk factors of non-communicable diseases (SuRFNCD-2007) were analyzed. We defined metabolic syndrome (MetS) according to the Adult Treatment Panel III (ATPIII) and International Diabetes Federation (IDF) criteria for 2125 subjects aging 25-64 years. The receiver operating characteristic (ROC) curves were used to determine the optimal cut-points for the diagnosis of MetS. The curves were depicted for non-high-density lipoprotein cholesterol (non-HDL-C) and difference of total non-HDL-C and LDL-C (Differential cholesterol or Diff-C) as predictors of MetS. Logistic regression was also performed in a complex sample analysis scheme. The area under the curve (AUC) with 95% Confidence intervals of total non-HDL-C was computed. Values were 0.693 (0.670-0.715) for IDF-defined MetS and 0.719 (0.697-0.740) for ATPIII criteria. The optimal non-HDL-C cut-point we recommend for both criteria is 153.50 mg/dl (sensitivity: 75.7%, specificity: 57.2%, with ATPIII; sensitivity: 73.2%, specificity: 57.1%, with IDF). Using IDF criteria, the accuracy of predictors were greater in non-diabetic subjects. AUC of Diff-C in DM (-) vs. DM (+) were 0.786 (0.765-0.807) vs. 0.627(0.549-0.705). Adults with high non-HDL-C were 4.42 times more likely to have ATPIII-defined MetS (≥190 vs. < 190 mg/dL). Elevated Diff-C corresponded to increased risk of the MetS (ORs: 10.71 and 26.29 for IDF and ATP

  17. Time-varying correlations between delta EEG power and heart rate variability in midlife women: The SWAN Sleep Study

    PubMed Central

    Rothenberger, Scott D.; Krafty, Robert T.; Taylor, Briana J.; Cribbet, Matthew R.; Thayer, Julian F.; Buysse, Daniel J.; Kravitz, Howard M.; Buysse, Evan D.; Hall, Martica H.

    2014-01-01

    No studies have evaluated the dynamic, time-varying, relationship between delta electroencephalographic (EEG) sleep and high frequency heart rate variability (HF-HRV) in women. Delta EEG and HF-HRV were measured during sleep in 197 midlife women (Mage =52.1, SD =2.2). Delta EEG-HF-HRV correlations in Non-Rapid Eye Movement (NREM) sleep were modeled as whole night averages and as continuous functions of time. The whole-night delta EEG-HF-HRV correlation was positive. Strongest correlations were observed during the first NREM sleep period preceding and following peak delta power. Time-varying correlations between delta EEG-HF-HRV were stronger in participants with sleep-disordered breathing and self-reported insomnia compared to healthy controls. The dynamic interplay between sleep and autonomic activity can be modeled across the night to examine within- and between-participant differences including individuals with and without sleep disorders. PMID:25431173

  18. Investigating Cooperative Behavior in Ecological Settings: An EEG Hyperscanning Study

    PubMed Central

    Petti, Manuela; He, Eric J.; De Giusti, Vittorio; He, Bin; Astolfi, Laura; Babiloni, Fabio

    2016-01-01

    The coordinated interactions between individuals are fundamental for the success of the activities in some professional categories. We reported on brain-to-brain cooperative interactions between civil pilots during a simulated flight. We demonstrated for the first time how the combination of neuroelectrical hyperscanning and intersubject connectivity could provide indicators sensitive to the humans’ degree of synchronization under a highly demanding task performed in an ecological environment. Our results showed how intersubject connectivity was able to i) characterize the degree of cooperation between pilots in different phases of the flight, and ii) to highlight the role of specific brain macro areas in cooperative behavior. During the most cooperative flight phases pilots showed, in fact, dense patterns of interbrain connectivity, mainly linking frontal and parietal brain areas. On the contrary, the amount of interbrain connections went close to zero in the non-cooperative phase. The reliability of the interbrain connectivity patterns was verified by means of a baseline condition represented by formal couples, i.e. pilots paired offline for the connectivity analysis but not simultaneously recorded during the flight. Interbrain density was, in fact, significantly higher in real couples with respect to formal couples in the cooperative flight phases. All the achieved results demonstrated how the description of brain networks at the basis of cooperation could effectively benefit from a hyperscanning approach. Interbrain connectivity was, in fact, more informative in the investigation of cooperative behavior with respect to established EEG signal processing methodologies applied at a single subject level. PMID:27124558

  19. Investigating Cooperative Behavior in Ecological Settings: An EEG Hyperscanning Study.

    PubMed

    Toppi, Jlenia; Borghini, Gianluca; Petti, Manuela; He, Eric J; De Giusti, Vittorio; He, Bin; Astolfi, Laura; Babiloni, Fabio

    2016-01-01

    The coordinated interactions between individuals are fundamental for the success of the activities in some professional categories. We reported on brain-to-brain cooperative interactions between civil pilots during a simulated flight. We demonstrated for the first time how the combination of neuroelectrical hyperscanning and intersubject connectivity could provide indicators sensitive to the humans' degree of synchronization under a highly demanding task performed in an ecological environment. Our results showed how intersubject connectivity was able to i) characterize the degree of cooperation between pilots in different phases of the flight, and ii) to highlight the role of specific brain macro areas in cooperative behavior. During the most cooperative flight phases pilots showed, in fact, dense patterns of interbrain connectivity, mainly linking frontal and parietal brain areas. On the contrary, the amount of interbrain connections went close to zero in the non-cooperative phase. The reliability of the interbrain connectivity patterns was verified by means of a baseline condition represented by formal couples, i.e. pilots paired offline for the connectivity analysis but not simultaneously recorded during the flight. Interbrain density was, in fact, significantly higher in real couples with respect to formal couples in the cooperative flight phases. All the achieved results demonstrated how the description of brain networks at the basis of cooperation could effectively benefit from a hyperscanning approach. Interbrain connectivity was, in fact, more informative in the investigation of cooperative behavior with respect to established EEG signal processing methodologies applied at a single subject level.

  20. Contradictory Reasoning Network: An EEG and fMRI Study

    PubMed Central

    Thai, Ngoc Jade; Seri, Stefano; Rotshtein, Pia; Tecchio, Franca

    2014-01-01

    Contradiction is a cornerstone of human rationality, essential for everyday life and communication. We investigated electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) in separate recording sessions during contradictory judgments, using a logical structure based on categorical propositions of the Aristotelian Square of Opposition (ASoO). The use of ASoO propositions, while controlling for potential linguistic or semantic confounds, enabled us to observe the spatial temporal unfolding of this contradictory reasoning. The processing started with the inversion of the logical operators corresponding to right middle frontal gyrus (rMFG-BA11) activation, followed by identification of contradictory statement associated with in the right inferior frontal gyrus (rIFG-BA47) activation. Right medial frontal gyrus (rMeFG, BA10) and anterior cingulate cortex (ACC, BA32) contributed to the later stages of process. We observed a correlation between the delayed latency of rBA11 response and the reaction time delay during inductive vs. deductive reasoning. This supports the notion that rBA11 is crucial for manipulating the logical operators. Slower processing time and stronger brain responses for inductive logic suggested that examples are easier to process than general principles and are more likely to simplify communication. PMID:24667491

  1. Contradictory reasoning network: an EEG and FMRI study.

    PubMed

    Porcaro, Camillo; Medaglia, Maria Teresa; Thai, Ngoc Jade; Seri, Stefano; Rotshtein, Pia; Tecchio, Franca

    2014-01-01

    Contradiction is a cornerstone of human rationality, essential for everyday life and communication. We investigated electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) in separate recording sessions during contradictory judgments, using a logical structure based on categorical propositions of the Aristotelian Square of Opposition (ASoO). The use of ASoO propositions, while controlling for potential linguistic or semantic confounds, enabled us to observe the spatial temporal unfolding of this contradictory reasoning. The processing started with the inversion of the logical operators corresponding to right middle frontal gyrus (rMFG-BA11) activation, followed by identification of contradictory statement associated with in the right inferior frontal gyrus (rIFG-BA47) activation. Right medial frontal gyrus (rMeFG, BA10) and anterior cingulate cortex (ACC, BA32) contributed to the later stages of process. We observed a correlation between the delayed latency of rBA11 response and the reaction time delay during inductive vs. deductive reasoning. This supports the notion that rBA11 is crucial for manipulating the logical operators. Slower processing time and stronger brain responses for inductive logic suggested that examples are easier to process than general principles and are more likely to simplify communication.

  2. The brain, obesity and addiction: an EEG neuroimaging study

    PubMed Central

    De Ridder, Dirk; Manning, Patrick; Leong, Sook Ling; Ross, Samantha; Sutherland, Wayne; Horwath, Caroline; Vanneste, Sven

    2016-01-01

    Obesity is among the greatest challenges facing healthcare systems with 20% of the world’s population afflicted. Great controversy exists whether obesity can be regarded as an addictive disorder or not. Recently the Yale Food Addiction Scale questionnaire has been developed as a tool to identify individuals with traits of addiction towards food. Using clinical and source localized EEG data we dichotomize obesity. Brain activity in food-addicted and non-food-addicted obese people is compared to alcohol-addicted and non-addicted lean controls. We show that food addiction shares common neural brain activity with alcohol addiction. This ‘addiction neural brain activity’ consists of the dorsal and pregenual anterior cingulate cortex, parahippocampal area and precuneus. Furthermore, common neural obesity neural brain activity exists as well. The ‘obesity neural brain activity’ consists of dorsal and pregenual anterior cingulate cortex, posterior cingulate extending into the precuneus/cuneus as well as the parahippocampal and inferior parietal area. However food-addicted differ from non-food-addicted obese people by opposite activity in the anterior cingulate gyrus. This food addiction and non-food-addiction obesity dichotomy demonstrates there is at least 2 different kinds of obesity with overlapping network activity, but different in anterior cingulate cortex activity. PMID:27658351

  3. Assessing the memorization of TV commercials with the use of high resolution EEG: a pilot study.

    PubMed

    Astolfi, L; Soranzo, R; Cincotti, F; Mattia, D; Scarano, G; Gaudiano, I; Marciani, M G; Salinari, S; De Vico Fallani, F; Babiloni, F

    2008-01-01

    The present work intends to evaluate the functional characteristics of the cerebral network during the successful memory encoding of TV commercials. We estimated the functional networks in the frequency domain from a set of high-resolution EEG data. High resolution EEG recordings were performed in a group of healthy subjects and the cortical activity during the observation of TV commercials was evaluated in several regions of interest coincident with the Brodmann areas (BAs). Summarizing the main results of the present study, a sign of the memorization of a particular set of TV commercials have been found in a group of investigated subjects with the aid of advanced modern tools for the acquisition and the processing of EEG data. The cerebral processes involved during the observation of TV commercials that were remembered successively by the population examined (RMB dataset) are generated by the posterior parietal cortices and the prefrontal areas, rather bilaterally and are irrespective of the frequency bands analyzed. Such results are compatible with previously results obtained from EEG recordings with superficial electrodes as well as with the brain activations observed with the use of MEG and fMRI devices.

  4. A method to study global spatial patterns related to sensory perception in scalp EEG.

    PubMed

    Ruiz, Yusely; Pockett, Susan; Freeman, Walter J; Gonzalez, Eduardo; Li, Guang

    2010-08-15

    Prior studies of multichannel ECoG from animals showed that beta and gamma oscillations carried perceptual information in both local and global spatial patterns of amplitude modulation, when the subjects were trained to discriminate conditioned stimuli (CS). Here the hypothesis was tested that similar patterns could be found in the scalp EEG human subjects trained to discriminate simultaneous visual-auditory CS. Signals were continuously recorded from 64 equispaced scalp electrodes and band-pass filtered. The Hilbert transform gave the analytic phase, which segmented the EEG into temporal frames, and the analytic amplitude, which expressed the pattern in each frame as a feature vector. Methods applied to the ECoG were adapted to the EEG for systematic search of the beta-gamma spectrum, the time period after CS onset, and the scalp surface to locate patterns that could be classified with respect to type of CS. Spatial patterns of EEG amplitude modulation were found from all subjects that could be classified with respect to stimulus combination type significantly above chance levels. The patterns were found in the beta range (15-22 Hz) but not in the gamma range. They occurred in three short bursts following CS onset. They were non-local, occupying the entire array. Our results suggest that the scalp EEG can yield information about the timing of episodically synchronized brain activity in higher cognitive function, so that future studies in brain-computer interfacing can be better focused. Our methods may be most valuable for analyzing data from dense arrays with very high spatial and temporal sampling rates.

  5. Reliability of information-based integration of EEG and fMRI data: a simulation study.

    PubMed

    Assecondi, Sara; Ostwald, Dirk; Bagshaw, Andrew P

    2015-02-01

    Most studies involving simultaneous electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) data rely on the first-order, affine-linear correlation of EEG and fMRI features within the framework of the general linear model. An alternative is the use of information-based measures such as mutual information and entropy, which can also detect higher-order correlations present in the data. The estimate of information-theoretic quantities might be influenced by several parameters, such as the numerosity of the sample, the amount of correlation between variables, and the discretization (or binning) strategy of choice. While these issues have been investigated for invasive neurophysiological data and a number of bias-correction estimates have been developed, there has been no attempt to systematically examine the accuracy of information estimates for the multivariate distributions arising in the context of EEG-fMRI recordings. This is especially important given the differences between electrophysiological and EEG-fMRI recordings. In this study, we drew random samples from simulated bivariate and trivariate distributions, mimicking the statistical properties of EEG-fMRI data. We compared the estimated information shared by simulated random variables with its numerical value and found that the interaction between the binning strategy and the estimation method influences the accuracy of the estimate. Conditional on the simulation assumptions, we found that the equipopulated binning strategy yields the best and most consistent results across distributions and bias correction methods. We also found that within bias correction techniques, the asymptotically debiased (TPMC), the jackknife debiased (JD), and the best upper bound (BUB) approach give similar results, and those are consistent across distributions.

  6. Two-color QCD at high density

    SciTech Connect

    Boz, Tamer; Skullerud, Jon-Ivar; Giudice, Pietro; Hands, Simon; Williams, Anthony G.

    2016-01-22

    QCD at high chemical potential has interesting properties such as deconfinement of quarks. Two-color QCD, which enables numerical simulations on the lattice, constitutes a laboratory to study QCD at high chemical potential. Among the interesting properties of two-color QCD at high density is the diquark condensation, for which we present recent results obtained on a finer lattice compared to previous studies. The quark propagator in two-color QCD at non-zero chemical potential is referred to as the Gor’kov propagator. We express the Gor’kov propagator in terms of form factors and present recent lattice simulation results.

  7. Structure-property relationships: Model studies on melt-extruded uniaxially-oriented high density polyethylene films having well defined morphologies

    NASA Astrophysics Data System (ADS)

    Zhou, Hongyi

    High density polyethylene (HDPE) films having simple and well-defined stacked lamellar morphology, either with or without a distinct presence of row-nucleated fibril structures, have been utilized as model materials to carry out investigations on solid state structure-property relationships. Mechanical tests, including tensile (INSTRON), creep (TMA), and dynamic mechanical (DMTA) tests, were performed at different angles with respect to the original machine direction (MD) of the melt extruded films; morphological changes as a result of these mechanical tests were detected by WAXS, SAXS, and TEM. Crystalline lamellar thickness and its distribution were determined by DSC, SAXS, TEM and AFM experiments. In the large strain deformation study (chapter 4.0), samples were stretched at 00sp°, 45sp° and 90sp° angles with respect to the original MD. A distinct orientation dependence of the tensile behavior was observed and correlated to the corresponding deformation modes and morphological changes, namely (1) lamellar separation and fragmentation by chain slip for the 00sp° stretch, (2) lamellar break-up via chain pull-out for the 90sp° stretch, and (3) lamellar shear, rotation and break-up through chain slip and/or tilt for the 45sp° stretch. A strong strengthening effect was observed for samples with row-nucleated fibril structures at the 00sp° stretch; whereas for the 90sp° stretch, the presence of such structures significantly limited deformability of the samples. In the dynamic strain mechanical alpha relaxation study (chapter 5.0), samples were tested at nine different angles with respect to the original MD, and the morphologies of samples before and after the dynamic tests were also investigated. The mechanical dispersions for the 00sp° and 90sp° tests were believed to arise essentially from the crystalline phase, and they contain contributions from two earlier recognized sub-relaxations of alphasbI and alphasbII. While for the 45sp° test, in addition to a

  8. Measuring the face-sensitive N170 with a gaming EEG system: A validation study.

    PubMed

    de Lissa, Peter; Sörensen, Sidsel; Badcock, Nicholas; Thie, Johnson; McArthur, Genevieve

    2015-09-30

    The N170 is a "face-sensitive" event-related potential (ERP) that occurs at around 170ms over occipito-temporal brain regions. The N170's potential to provide insight into the neural processing of faces in certain populations (e.g., children and adults with cognitive impairments) is limited by its measurement in scientific laboratories that can appear threatening to some people. The advent of cheap, easy-to-use portable gaming EEG systems provides an opportunity to record EEG in new contexts and populations. This study tested the validity of the face-sensitive N170 ERP measured with an adapted commercial EEG system (the Emotiv EPOC) that is used at home by gamers. The N170 recorded through both the gaming EEG system and the research EEG system exhibited face-sensitivity, with larger mean amplitudes in response to the face stimuli than the non-face stimuli, and a delayed N170 peak in response to face inversion. The EPOC system produced very similar N170 ERPs to a research-grade Neuroscan system, and was capable of recording face-sensitivity in the N170, validating its use as research tool in this arena. This opens new possibilities for measuring the face-sensitive N170 ERP in people who cannot travel to a traditional ERP laboratory (e.g., elderly people in care), who cannot tolerate laboratory conditions (e.g., people with autism), or who need to be tested in situ for practical or experimental reasons (e.g., children in schools). Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Hemispheric Specialization Varies with EEG Brain Resting States and Phase of Menstrual Cycle

    PubMed Central

    Cacioppo, Stephanie; Bianchi-Demicheli, Francesco; Bischof, Paul; DeZiegler, Dominique; Michel, Christoph M.; Landis, Theodor

    2013-01-01

    A growing body of behavioral studies has demonstrated that women’s hemispheric specialization varies as a function of their menstrual cycle, with hemispheric specialization enhanced during their menstruation period. Our recent high-density electroencephalogram (EEG) study with lateralized emotional versus neutral words extended these behavioral results by showing that hemispheric specialization in men, but not in women under birth-control, depends upon specific EEG resting brain states at stimulus arrival, suggesting that hemispheric specialization may be pre-determined at the moment of the stimulus onset. To investigate whether EEG brain resting state for hemispheric specialization could vary as a function of the menstrual phase, we tested 12 right-handed healthy women over different phases of their menstrual cycle combining high-density EEG recordings and the same lateralized lexical decision paradigm with emotional versus neutral words. Results showed the presence of specific EEG resting brain states, associated with hemispheric specialization for emotional words, at the moment of the stimulus onset during the menstruation period only. These results suggest that the pre-stimulus EEG pattern influencing hemispheric specialization is modulated by the hormonal state. PMID:23638185

  10. High density scintillating glass proton imaging detector

    NASA Astrophysics Data System (ADS)

    Wilkinson, C. J.; Goranson, K.; Turney, A.; Xie, Q.; Tillman, I. J.; Thune, Z. L.; Dong, A.; Pritchett, D.; McInally, W.; Potter, A.; Wang, D.; Akgun, U.

    2017-03-01

    In recent years, proton therapy has achieved remarkable precision in delivering doses to cancerous cells while avoiding healthy tissue. However, in order to utilize this high precision treatment, greater accuracy in patient positioning is needed. An accepted approximate uncertainty of +/-3% exists in the current practice of proton therapy due to conversions between x-ray and proton stopping power. The use of protons in imaging would eliminate this source of error and lessen the radiation exposure of the patient. To this end, this study focuses on developing a novel proton-imaging detector built with high-density glass scintillator. The model described herein contains a compact homogeneous proton calorimeter composed of scintillating, high density glass as the active medium. The unique geometry of this detector allows for the measurement of both the position and residual energy of protons, eliminating the need for a separate set of position trackers in the system. Average position and energy of a pencil beam of 106 protons is used to reconstruct the image rather than by analyzing individual proton data. Simplicity and efficiency were major objectives in this model in order to present an imaging technique that is compact, cost-effective, and precise, as well as practical for a clinical setting with pencil-beam scanning proton therapy equipment. In this work, the development of novel high-density glass scintillator and the unique conceptual design of the imager are discussed; a proof-of-principle Monte Carlo simulation study is performed; preliminary two-dimensional images reconstructed from the Geant4 simulation are presented.

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

    PubMed

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

    2014-03-01

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

  12. Brain scale-free properties in awake rest and NREM sleep: a simultaneous EEG/fMRI study.

    PubMed

    Lei, Xu; Wang, Yulin; Yuan, Hong; Chen, Antao

    2015-03-01

    Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) studies revealed that spontaneous activity in the brain has scale-invariant properties, as indicated by a frequency spectrum that follows a power-law distribution. However, current knowledge about the exact relationship between scaling properties in EEG and fMRI signals is very limited. To address this question, we collected simultaneous EEG-fMRI data in healthy individuals during resting wakefulness and non-rapid eye movement (NREM) sleep. For either of these conditions, we found that both EEG and fMRI power spectra followed a power-law distribution. Furthermore, the EEG and fMRI scaling exponents were highly variable across subjects, and sensitive to the choice of reference and nuisance variables in EEG and fMRI data, respectively. Interestingly, the EEG exponent of the whole brain selectively corresponded to the fMRI exponent of the thalamus during NREM sleep. Together, our findings suggest that scale-free brain activity is characterized by robust temporal structures and behavioral significance. This motivates future studies to unravel its physiological mechanisms, as well as its relevance to behavior.

  13. Refractory Epilepsy-MRI, EEG and CT scan, a Correlative Clinical Study

    PubMed Central

    Nikodijevic, Dijana; Baneva–Dolnenec, Natalija; Petrovska-Cvetkovska, Dragana; Caparoska, Daniela

    2016-01-01

    OBJECTIVES: Refractory epilepsies (RE), as well as, the surgically correctable syndromes, are of great interest, since they affect the very young population of children and adolescents. The early diagnosis and treatment are very important in preventing the psychosocial disability. Therefore MRI and EEG are highly sensitive methods in the diagnosis and localization of epileptogenic focus, but also in pre-surgical evaluation of these patients. The aim of our study is to correlate the imaging findings of EEG, MRI and CT scan in refractory symptomatic epilepsies, and to determine their specificity in detecting the epileptogenic focus. METHODS: The study was prospective with duration of over two years, open-labelled, and involved a group of 37 patients that had been evaluated and diagnosed as refractory epilepsy patients. In the evaluation the type and frequency of seizures were considered, together with the etiologic factors and their association, and finally the risk for developing refractory epilepsy was weighted. EEG and MRI findings and CT scan results were evaluated for their specificity and sensitivity in detecting the epileptogenic focus, and the correlation between them was analyzed. RESULTS: Regarding the type of seizures considered in our study, the patients with PCS (partial complex seizures) dominated, as opposed to those with generalized seizures (GS) (D=1.178, p < 0.05). Positive MRI findings were registered in 28 patients (75.7%). Most of them were patients with hippocampal sclerosis, 12 (42.8%), and also they were found to have the highest risk of developing refractory epilepsy (RE) (Odds ratio = 5.7), and the highest association between the etiologic factor and refractory epilepsy (p < 0.01). In detecting the epileptogenic focus, a significant difference was found (p < 0.01) between MRI and CT scan findings, especially in patients with hippocampal sclerosis and cerebral malformations. There was a strong correlation between the MRI findings and the

  14. Correlation of invasive EEG and scalp EEG.

    PubMed

    Ramantani, Georgia; Maillard, Louis; Koessler, Laurent

    2016-10-01

    Ever since the implementation of invasive EEG recordings in the clinical setting, it has been perceived that a considerable proportion of epileptic discharges present at a cortical level are missed by routine scalp EEG recordings. Several in vitro, in vivo, and simulation studies have been performed in the past decades aiming to clarify the interrelations of cortical sources with their scalp and invasive EEG correlates. The amplitude ratio of cortical potentials to their scalp EEG correlates, the extent of the cortical area involved in the discharge, as well as the localization of the cortical source and its geometry have been each independently linked to the recording of the cortical discharge with scalp electrodes. The need to elucidate these interrelations has been particularly imperative in the field of epilepsy surgery with its rapidly growing EEG-based localization technologies. Simultaneous multiscale EEG recordings with scalp, subdural and/or depth electrodes, applied in presurgical epilepsy workup, offer an excellent opportunity to shed some light to this fundamental issue. Whereas past studies have considered predominantly neocortical sources in the context of temporal lobe epilepsy, current investigations have included deep sources, as in mesial temporal epilepsy, as well as extratemporal sources. Novel computational tools may serve to provide surrogates for the shortcomings of EEG recording methodology and facilitate further developments in modern electrophysiology.

  15. Combining TMS and EEG to study cognitive function and cortico-cortico interactions

    PubMed Central

    Taylor, Paul CJ; Walsh, Vincent; Eimer, Martin

    2009-01-01

    There has long been an interest in exploring the functional dynamics of the brain’s connectivity during cognitive processing, and some recent methodological developments now allow us to test important long-standing hypotheses. This review focuses on the recent development of combined online transcranial magnetic stimulation and electroencephalography (TMS-EEG) and on new studies that have employed this combination to study causal interactions between neural areas involved in perception and cognition. PMID:18485496

  16. An ordered Arabidopsis thaliana mitochondrial cDNA library on high-density filters allows rapid systematic analysis of plant gene expression: a pilot study.

    PubMed

    Giegé, P; Konthur, Z; Walter, G; Brennicke, A

    1998-09-01

    The availability of the complete sequence of a genome allows a systematic analysis of its expression. Gene-specific variations of transcription levels and phenomena such as transcript processing and RNA editing require large numbers of clones to be examined. For the completely sequenced mitochondrial genome of Arabidopsis thaliana we adapted robot technology to identify and characterize expressed genes. A cDNA library of about 50,000 clones was constructed, robot-ordered into 384-well microtitre plates and spotted onto high-density filter membranes. These filters permit the isolation of large numbers of specific cDNA clones in a single hybridization step. The cox1, cox2 and cox3 genes were used to evaluate the feasibility and efficiency of this approach. A cluster of RNA editing sites observed outside the cox3 coding region identifies a novel reading frame orf95 in higher plants with significant similarity to a subunit of respiratory chain complex II.

  17. A Comparative Study on AC Conductivity and Dielectric Behavior of Multiwalled Carbon Nanotubes and Polyaniline Coated Multiwalled Carbon Nanotubes Filled High Density Polyethylene-Carbon Black Nanocomposites

    SciTech Connect

    Dinesh, P.; Renukappa, N. M.; Siddaramaiah; Lee, J. H.; Jeevananda, T.

    2010-10-04

    This paper presents an experimental investigation on AC conductivity and dielectric behavior of carbon black reinforced high density polyethylene (HDPE-CB) and HDPE-CB filled with multiwalled carbon nanotubes (MWNTs-CB-HDPE) and Polyaniline (PAni) coated MWNTs-CB-HDPE nanocomposites. The electrical properties such as dielectric constant ({epsilon}'), dissipation factor (tan {delta}) and AC conductivity ({sigma}{sub ac}) of nanocomposites have been measured with reference to the weight fraction (0.5 and 1 wt% MWNTs), frequency (75 KHz-30 MHz), temperature (25-90 deg. C) and sea water ageing. The experimental results showed that the increased AC conductivity and dielectric constant of the nanocomposites were influenced by PAni coated MWNTs in HDPE-CB nanocomposites. The value of dielectric constant and tan {delta} decreased with increasing frequency. Further more, above 5 MHz the AC conductivity increases drastically whereas significant effect on tan {delta} was observed in less than 1 MHz.

  18. Impact of red blood cells count on the relationship between high density lipoproteins and the prevalence and extent of coronary artery disease: a single centre study [corrected].

    PubMed

    Schaffer, Alon; Verdoia, Monica; Cassetti, Ettore; Barbieri, Lucia; Perrone-Filardi, Pasquale; Marino, Paolo; De Luca, Giuseppe

    2015-07-01

    We have hypothesized that high red blood cells (RBC) count can potentially play an atheroprotective role in patients with coronary atherosclerosis. We, therefore, have investigated the relationship between high density lipoproteins cholesterol (HDL-C) and RBC levels in patients undergoing coronary angiography. Coronary artery disease (CAD) is a major cause of mortality. Impaired lipid profile represents a major risk factor for atherosclerosis. High density lipoprotein (HDL) is a key factor in atherosclerosis disease development. RBC can mimic HDL's reverse cholesterol transportation with a potential atheroprotective role. Coronary angiography has been evaluated in 3,534 patients. Fasting samples were collected for haematology and lipids levels assessment. Coronary disease was defined for at least 1 vessel stenosis >50 %. Patients were divided according to HDL-C and RBC tertiles. Lower HDL-C was significantly associated to the prevalence of CAD (84.8 vs 78.5 vs 67.3 %, p ≤ 0.001; adjusted OR [95 % CI] = 1.55 [1.3-1.8], p < 0.001) and severe CAD (30 % vs 30 % vs 24.4 %, p = 0.002; adjusted OR [95 % CI] = 1.08 [1.01-1.16], p = 0.02), this relationship was maintained even dividing our population according to RBC tertiles (p < 0.001).In conclusion, HDL-C levels are directly related to RBC count and inversely to the prevalence and extent of coronary disease. Higher RBC levels can reduce the risk of CAD in patients with lower HDL-C levels, suggesting an important atheroprotective role.

  19. Green tea with high-density catechins improves liver function and fat infiltration in non-alcoholic fatty liver disease (NAFLD) patients: a double-blind placebo-controlled study.

    PubMed

    Sakata, Ryuichiro; Nakamura, Toru; Torimura, Takuji; Ueno, Takato; Sata, Michio

    2013-11-01

    Catechins, a major component of green tea extract, have anti-hyperlipidemic effects. The present study investigated the effects of consumption of green tea with high-density catechins in non-alcoholic fatty liver disease (NAFLD) patients. Seventeen patients with NAFLD consumed green tea with high-density catechins, low-density catechins or a placebo for 12 weeks in a randomized double-blind study. Ultrasonography and computed tomography (CT) were performed at baseline and after 12 weeks. Serum alanine aminotransferase (ALT) levels and urine 8-isoprostane were monitored and compared to baseline at 4, 8 and 12 weeks. Body fat was significantly decreased in the high-density catechin group compared with the placebo and low-density catechin groups after 12 weeks of consumption. All the patients in the high-density catechin group showed a significantly improved liver-to-spleen CT attenuation ratio compared with the placebo and low-density catechin groups after 12 weeks of consumption. The high-density catechin group significantly decreased serum ALT levels and reduced urinary 8-isoprostane excretion compared with the placebo and low-density catechin group after 12 weeks of consumption. Based on a reduced proportion of body fat as estimated by bioimpedance measurement, increased liver-to-spleen CT attenuation ratio, decreased serum ALT levels and reduced urinary 8-isoprostane excretion, we concluded that 12 weeks of 700 ml per day of green tea containing >1 g catechin improved liver fat content and inflammation by reducing oxidative stress in patients with NAFLD.

  20. Manual lymph drainage attenuates frontal EEG asymmetry in subjects with psychological stress: a preliminary study.

    PubMed

    Shim, Jung-Myo; Kim, Sung-Joong

    2014-04-01

    [Purpose] The purpose of this preliminary study was to investigate the effect of manual lymph drainage (MLD) of the neck on frontal electroencephalogram (EEG) asymmetry in subjects with psychological stress. [Subjects] Thirteen subjects with psychological stress participated in the study. [Methods] Subjects received MLD of the neck for 15 min. [Results] Analysis of the frontal asymmetry index showed that the energy shift in the alpha frequency band from the left hemisphere to the right hemisphere after MLD resulted in greater left-side activation (positive asymmetry values), which could be related to the positive emotional state observed particularly in the F7-F8 area. [Conclusion] These preliminary findings suggest that frontal EEG asymmetry was significantly attenuated after MLD.

  1. The interrelated effect of sleep and learning in dogs (Canis familiaris); an EEG and behavioural study.

    PubMed

    Kis, Anna; Szakadát, Sára; Gácsi, Márta; Kovács, Enikő; Simor, Péter; Török, Csenge; Gombos, Ferenc; Bódizs, Róbert; Topál, József

    2017-02-06

    The active role of sleep in memory consolidation is still debated, and due to a large between-species variation, the investigation of a wide range of different animal species (besides humans and laboratory rodents) is necessary. The present study applied a fully non-invasive methodology to study sleep and memory in domestic dogs, a species proven to be a good model of human awake behaviours. Polysomnography recordings performed following a command learning task provide evidence that learning has an effect on dogs' sleep EEG spectrum. Furthermore, spectral features of the EEG were related to post-sleep performance improvement. Testing an additional group of dogs in the command learning task revealed that sleep or awake activity during the retention interval has both short- and long-term effects. This is the first evidence to show that dogs' human-analogue social learning skills might be related to sleep-dependent memory consolidation.

  2. ADOLECSENT MANIA, EEG ABNORMALITY AND RESPONSE TO ANTICONVULSANTS: A THREE - YEAR FOLLOW-UP STUDY

    PubMed Central

    Aich, Tapas K.; Sinha, Vinod Kumar; Nizami, Hauque S.

    2001-01-01

    We had reported earlier (1998) a high percentage of moderate to severe EEG abnormalities (43.75% of cases) amongst adolescent manic population. Sixteen adolescent manics, with a mean age of 14 9 years, diagnosed according to ICD-10 were taken up for the initial study. Present study is the three-year follow-up report of 67.75% (11 out of 16) of the original patient population. All these patients were subjected fc 21-channel EEG and anticonvulsant drugs were started to all. Follow-up data showed that 3 out of 6 patients, who discontinued medications, were relapsed during this 3 years period. But none of the 5 patients, who regularly took prescribed medicines, relapsed during the same period. Significance of these findings in relapse prevention and the role of anticonvulsants, particularly in relation to adolescent mania, have been emphasized. PMID:21407863

  3. The interrelated effect of sleep and learning in dogs (Canis familiaris); an EEG and behavioural study

    PubMed Central

    Kis, Anna; Szakadát, Sára; Gácsi, Márta; Kovács, Enikő; Simor, Péter; Török, Csenge; Gombos, Ferenc; Bódizs, Róbert; Topál, József

    2017-01-01

    The active role of sleep in memory consolidation is still debated, and due to a large between-species variation, the investigation of a wide range of different animal species (besides humans and laboratory rodents) is necessary. The present study applied a fully non-invasive methodology to study sleep and memory in domestic dogs, a species proven to be a good model of human awake behaviours. Polysomnography recordings performed following a command learning task provide evidence that learning has an effect on dogs’ sleep EEG spectrum. Furthermore, spectral features of the EEG were related to post-sleep performance improvement. Testing an additional group of dogs in the command learning task revealed that sleep or awake activity during the retention interval has both short- and long-term effects. This is the first evidence to show that dogs’ human-analogue social learning skills might be related to sleep-dependent memory consolidation. PMID:28165489

  4. Some novel phenomena at high density

    NASA Astrophysics Data System (ADS)

    Berkowitz, Evan Scott

    Astrophysical environments probe matter in ways impossible on Earth. In particular, matter in compact objects are extraordinarily dense. In this thesis we discuss two phenomena that may occur at high density. First, we study toroidal topological solitons called vortons, which can occur in the kaon-condensed color-flavor-locked phase of high-density quark matter, a candidate phase for the core of some neutron stars. We show that vortons have a large radius compared to their thickness if their electrical charge is on the order of 104 times the fundamental charge. We show that shielding of electric fields by electrons dramatically reduces the size of a vorton. Second, we study an unusual phase of degenerate electrons and nonrelativistic Bose-condensed helium nuclei that may exist in helium white dwarfs. We show that this phase supports a previously-unknown gapless mode, known as the half-sound, that radically alters the material's specific heat, and can annihilate into neutrinos. We provide evidence that this neutrino radiation is negligible compared to the star's surface photoemission.

  5. A genome wide association study of fast beta EEG in families of European ancestry.

    PubMed

    Meyers, Jacquelyn L; Zhang, Jian; Manz, Niklas; Rangaswamy, Madhavi; Kamarajan, Chella; Wetherill, Leah; Chorlian, David B; Kang, Sun J; Bauer, Lance; Hesselbrock, Victor; Kramer, John; Kuperman, Samuel; Nurnberger, John I; Tischfield, Jay; Wang, Jen Chyong; Edenberg, Howard J; Goate, Alison; Foroud, Tatiana; Porjesz, Bernice

    2017-05-01

    Differences in fast beta (20-28Hz) electroencephalogram (EEG) oscillatory activity distinguish some individuals with psychiatric and substance use disorders, suggesting that it may be a useful endophenotype for studying the genetics of disorders characterized by neural hyper-excitability. Despite the high heritability estimates provided by twin and family studies, there have been relatively few genetic studies of beta EEG, and to date only one genetic association finding has replicated (i.e., GABRA2). In a sample of 1564 individuals from 117 families of European Ancestry (EA) drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a Genome-Wide Association Study (GWAS) on resting-state fronto-central fast beta EEG power, adjusting regression models for family relatedness, age, sex, and ancestry. To further characterize genetic findings, we examined the functional and behavioral significance of GWAS findings. Three intronic variants located within DSE (dermatan sulfate epimerase) on 6q22 were associated with fast beta EEG at a genome wide significant level (p<5×10(-8)). The most significant SNP was rs2252790 (p<2.6×10(-8); MAF=0.36; β=0.135). rs2252790 is an eQTL for ROS1 expressed most robustly in the temporal cortex (p=1.2×10(-6)) and for DSE/TSPYL4 expressed most robustly in the hippocampus (p=7.3×10(-4); β=0.29). Previous studies have indicated that DSE is involved in a network of genes integral to membrane organization; gene-based tests indicated that several variants within this network (i.e., DSE, ZEB2, RND3, MCTP1, and CTBP2) were also associated with beta EEG (empirical p<0.05), and of these genes, ZEB2 and CTBP2 were associated with DSM-V Alcohol Use Disorder (AUD; empirical p<0.05).' In this sample of EA families enriched for AUDs, fast beta EEG is associated with variants within DSE on 6q22; the most significant SNP influences the mRNA expression of DSE and ROS1 in hippocampus and temporal cortex, brain regions

  6. Face, eye, and body selective responses in fusiform gyrus and adjacent cortex: an intracranial EEG study

    PubMed Central

    Engell, Andrew D.; McCarthy, Gregory

    2014-01-01

    Functional MRI (fMRI) studies have investigated the degree to which processing of whole faces, face-parts, and bodies are differentially localized within the fusiform gyrus and adjacent ventral occipitotemporal cortex. While some studies have emphasized the spatial differentiation of processing into discrete areas, others have emphasized the overlap of processing and the importance of distributed patterns of activity. Intracranial EEG (iEEG) recorded from subdural electrodes provides excellent temporal and spatial resolution of local neural activity, and thus provides an alternative method to fMRI for studying differences and commonalities in face and body processing. In this study we recorded iEEG from 12 patients while they viewed images of novel faces, isolated eyes, headless bodies, and flowers. Event-related potential analysis identified 69 occipitotemporal sites at which there was a face-, eye-, or body-selective response when contrasted to flowers. However, when comparing faces, eyes, and bodies to each other at these sites, we identified only 3 face-specific, 13 eye-specific, and 1 body-specific electrodes. Thus, at the majority of sites, faces, eyes, and bodies evoked similar responses. However, we identified ten locations at which the amplitude of the responses spatially varied across adjacent electrodes, indicating that the configuration of current sources and sinks were different for faces, eyes, and bodies. Our results also demonstrate that eye-sensitive regions are more abundant and more purely selective than face- or body-sensitive regions, particularly in lateral occipitotemporal cortex. PMID:25191255

  7. Face, eye, and body selective responses in fusiform gyrus and adjacent cortex: an intracranial EEG study.

    PubMed

    Engell, Andrew D; McCarthy, Gregory

    2014-01-01

    Functional MRI (fMRI) studies have investigated the degree to which processing of whole faces, face-parts, and bodies are differentially localized within the fusiform gyrus and adjacent ventral occipitotemporal cortex. While some studies have emphasized the spatial differentiation of processing into discrete areas, others have emphasized the overlap of processing and the importance of distributed patterns of activity. Intracranial EEG (iEEG) recorded from subdural electrodes provides excellent temporal and spatial resolution of local neural activity, and thus provides an alternative method to fMRI for studying differences and commonalities in face and body processing. In this study we recorded iEEG from 12 patients while they viewed images of novel faces, isolated eyes, headless bodies, and flowers. Event-related potential analysis identified 69 occipitotemporal sites at which there was a face-, eye-, or body-selective response when contrasted to flowers. However, when comparing faces, eyes, and bodies to each other at these sites, we identified only 3 face-specific, 13 eye-specific, and 1 body-specific electrodes. Thus, at the majority of sites, faces, eyes, and bodies evoked similar responses. However, we identified ten locations at which the amplitude of the responses spatially varied across adjacent electrodes, indicating that the configuration of current sources and sinks were different for faces, eyes, and bodies. Our results also demonstrate that eye-sensitive regions are more abundant and more purely selective than face- or body-sensitive regions, particularly in lateral occipitotemporal cortex.

  8. Headache as an Aura of Epilepsy: Video-EEG Monitoring Study.

    PubMed

    Kim, Dong Wook; Sunwoo, Jun-Sang; Lee, Sang Kun

    2016-04-01

    Headache can be associated with epilepsy as a pre-ictal, ictal, or post-ictal phenomenon; however, studies of patients with headache as an epileptic aura are scarce. We performed the present study to investigate the incidence and characteristics of headache as an epileptic aura, via confirmation of electroencephalography (EEG) changes by video-EEG monitoring. Data of aura and clinical seizure episodes of 831 consecutive patients who undertook video-EEG monitoring were analyzed retrospectively. For patients who had headache as an aura, information on the detailed features of headache was acquired, including location, nature, duration, and the presence of accompanying symptoms. Video-recorded clinical seizures, EEG findings, and neuroimaging data were used to determine the ictal onset areas in the patients. Six out of 831 (0.7%) patients experienced headache as aura (age range, 25-52 years), all of whom had partial seizures. The incidence of pre-ictal headache was 6.3% (25/831), and post-ictal headache was 30.9% (257/831). In patients with headache as aura, five patients described headache as the most frequent aura, and headache was the second most frequent aura in one patient. The characteristics of headache were hemicrania epileptica in two patients, tension-type headache in another two patients, and migraine-like headache in the remaining two patients. No patient met the diagnostic criteria of ictal epileptic headache or migraine aura-triggered seizure. Our study showed that headache as an aura is uncommon in adult patients with epilepsy, and that headache can present as diverse features, including hemicrania epileptica, tension-type headache, and migraine-like headache. Further studies are necessary to characterize the features of headache as an epileptic aura in adult patients with epilepsy. © 2016 American Headache Society.

  9. Task-related functional connectivity in autism spectrum conditions: an EEG study using wavelet transform coherence

    PubMed Central

    2013-01-01

    Background Autism Spectrum Conditions (ASC) are a set of pervasive neurodevelopmental conditions characterized by a wide range of lifelong signs and symptoms. Recent explanatory models of autism propose abnormal neural connectivity and are supported by studies showing decreased interhemispheric coherence in individuals with ASC. The first aim of this study was to test the hypothesis of reduced interhemispheric coherence in ASC, and secondly to investigate specific effects of task performance on interhemispheric coherence in ASC. Methods We analyzed electroencephalography (EEG) data from 15 participants with ASC and 15 typical controls, using Wavelet Transform Coherence (WTC) to calculate interhemispheric coherence during face and chair matching tasks, for EEG frequencies from 5 to 40 Hz and during the first 400 ms post-stimulus onset. Results Results demonstrate a reduction of interhemispheric coherence in the ASC group, relative to the control group, in both tasks and for all electrode pairs studied. For both tasks, group differences were generally observed after around 150 ms and at frequencies lower than 13 Hz. Regarding within-group task comparisons, while the control group presented differences in interhemispheric coherence between faces and chairs tasks at various electrode pairs (FT7-FT8, TP7-TP8, P7-P8), such differences were only seen for one electrode pair in the ASC group (T7-T8). No significant differences in EEG power spectra were observed between groups. Conclusions Interhemispheric coherence is reduced in people with ASC, in a time and frequency specific manner, during visual perception and categorization of both social and inanimate stimuli and this reduction in coherence is widely dispersed across the brain. Results of within-group task comparisons may reflect an impairment in task differentiation in people with ASC relative to typically developing individuals. Overall, the results of this research support the value of WTC in examining the time

  10. Study of impedance spectra for dry and wet EarEEG electrodes.

    PubMed

    Kappel, Simon L; Kidmose, Preben

    2015-01-01

    EarEEG is a novel recordings concept where electrodes are embedded on the surface of an earpiece customized to the individual anatomical shape of the users ear. A key parameter for recording EEG signals of good quality is a stable and low impedance electrode-body interface. This study characterizes the impedance for dry and wet EarEEG electrodes in a study of 10 subjects. A custom made and automated setup was used to characterize the impedance spectrum from 0.1 Hz-2 kHz. The study of dry electrodes showed a mean (standard deviation) low frequency impedance of the canal electrodes of 1.2 MΩ (1.4 MΩ) and the high frequency impedance was 230 kΩ (220 kΩ). For wet electrodes the low frequency impedance was 34 kΩ (37 kΩ) and the high frequency impedance was 5.1 kΩ (4.4 kΩ). The high standard deviation of the impedance for dry electrodes imposes very high requirements for the input impedance of the amplifier in order to achieve an acceptable common-mode rejection. The wet electrode impedance was in line with what is typical for a wet electrode interface.

  11. Modification of EEG functional connectivity and EEG power spectra in overweight and obese patients with food addiction: An eLORETA study.

    PubMed

    Imperatori, Claudio; Fabbricatore, Mariantonietta; Innamorati, Marco; Farina, Benedetto; Quintiliani, Maria Isabella; Lamis, Dorian A; Mazzucchi, Edoardo; Contardi, Anna; Vollono, Catello; Della Marca, Giacomo

    2015-12-01

    We evaluated the modifications of electroencephalographic (EEG) power spectra and EEG connectivity in overweight and obese patients with elevated food addiction (FA) symptoms. Fourteen overweight and obese patients (3 men and 11 women) with three or more FA symptoms and fourteen overweight and obese patients (3 men and 11 women) with two or less FA symptoms were included in the study. EEG was recorded during three different conditions: 1) five minutes resting state (RS), 2) five minutes resting state after a single taste of a chocolate milkshake (ML-RS), and 3) five minutes resting state after a single taste of control neutral solution (N-RS). EEG analyses were conducted by means of the exact Low Resolution Electric Tomography software (eLORETA). Significant modification was observed only in the ML-RS condition. Compared to controls, patients with three or more FA symptoms showed an increase of delta power in the right middle frontal gyrus (Brodmann Area [BA] 8) and in the right precentral gyrus (BA 9), and theta power in the right insula (BA 13) and in the right inferior frontal gyrus (BA 47). Furthermore, compared to controls, patients with three or more FA symptoms showed an increase of functional connectivity in fronto-parietal areas in both the theta and alpha band. The increase of functional connectivity was also positively associated with the number of FA symptoms. Taken together, our results show that FA has similar neurophysiological correlates of other forms of substance-related and addictive disorders suggesting similar psychopathological mechanisms.

  12. The relationship of theory and methodology in EEG studies of mental activity.

    PubMed

    Lazarev, Vladimir V

    2006-12-01

    Due to the multidisciplinary character of psychophysiology, the problem of comparability of psychological and physiological phenomena of different natures and levels of organization has always been raised. This requires the interaction of theory and methodology to appropriately address the specifics of the psychophysiological paradigm, all the while maintaining their grounding in the actual psychological and physiological concepts. The history of EEG studies of mental activity shows that a weak theoretical basis at certain stages can result not only in methodological crises but can also affect empirical data collection and interpretation. An adequate theory can lend strong support to the methodology with "brain-oriented" structuring of psychological tasks and such a theory improves the neurophysiological informative value of the EEG parameters referring to the psychological characteristics of mental processes etc. On the other hand, the great importance of the EEG recording and processing techniques can result in overrating technological progress, hence frequently holding back meaningful interpretation and construction of a comprehensive psychophysiological conceptual framework. This in turn causes demands for higher material and intellectual outlays, due to overspecialization in research, and results in work duplication as well as the creation of a fragmentary knowledge structure. This article illustrates how the multidisciplinary interaction of theory and methodology, when focused on theoretical problems, can yield a series of concepts with escalating levels of integration, bringing together such different branches of psychophysiology as the study of functional states and of individual differences. As a result, this extends the theoretical model based on normal material to encompass borderline constitutional psychopathology.

  13. No evidence for mirror system dysfunction in schizophrenia from a multimodal TMS/EEG study.

    PubMed

    Andrews, Sophie C; Enticott, Peter G; Hoy, Kate E; Thomson, Richard H; Fitzgerald, Paul B

    2015-08-30

    Dysfunctional mirror neuron systems have been proposed to contribute to the social cognitive deficits observed in schizophrenia. A few studies have explored mirror systems in schizophrenia using various techniques such as TMS (levels of motor resonance) or EEG (levels of mu suppression), with mixed results. This study aimed to use a novel multimodal approach (i.e. concurrent TMS and EEG) to further investigate mirror systems and social cognition in schizophrenia. Nineteen individuals with schizophrenia or schizoaffective disorder and 19 healthy controls participated. Single-pulse TMS was applied to M1 during the observation of hand movements designed to elicit mirror system activity. Single EEG electrodes (C3, CZ, C4) recorded brain activity. Participants also completed facial affect recognition and theory of mind tasks. The schizophrenia group showed significant deficits in facial affect recognition and higher level theory of mind compared to healthy controls. A significant positive relationship was revealed between mu suppression and motor resonance for the overall sample, indicating concurrent validity of these measures. Levels of mu suppression and motor resonance were not significantly different between groups. These findings indicate that in stable outpatients with schizophrenia, mirror system functioning is intact, and therefore their social cognitive difficulties may be caused by alternative pathophysiology.

  14. Electroencephalographic (EEG) measurements of mindfulness-based Triarchic body-pathway relaxation technique: a pilot study.

    PubMed

    Chan, Agnes S; Han, Yvonne M Y; Cheung, Mei-Chun

    2008-03-01

    The "Triarchic body-pathway relaxation technique" (TBRT) is a form of ancient Chinese mindfulness-based meditation professed to give rise to positive emotions and a specific state of consciousness in which deep relaxation and internalized attention coexist. The purpose of this study was to examine the EEG pattern generated during the practice of this mindfulness exercise, and compare it to music listening which has been shown to induce positive emotions. Nineteen college students (aged 19-22 years) participated in the study. Each participant listened to both the TBRT and music audiotapes while EEG was recorded. The order of presentation was counterbalanced to avoid order effect. Two EEG indicators were used: (1) alpha asymmetry index, an indicator for left-sided anterior activation, as measure of positive emotions, and (2) frontal midline theta activity, as a measure for internalized attention. Increased left-sided activation, a pattern associated with positive emotions, was found during both TBRT exercise and music conditions. However, only TBRT exercise was shown to exhibit greater frontal midline theta power, a pattern associated with internalized attention. These results provided evidence to support that the TBRT gives rise to positive emotional experience, accompanied by focused internalized attention.

  15. A Study on Analysis of EEG Caused by Grating Stimulation Imaging

    NASA Astrophysics Data System (ADS)

    Urakawa, Hiroshi; Nishimura, Toshihiro; Tsubai, Masayoshi; Itoh, Kenji

    Recently, many researchers have studied a visual perception. Focus is attended to studies of the visual perception phenomenon by using the grating stimulation images. The previous researches have suggested that a subset of retinal ganglion cells responds to motion in the receptive field center, but only if the wider surround moves with a different trajectory. We discuss the function of human retina, and measure and analysis EEG(electroencephalography) of a normal subject who looks on grating stimulation images. We confirmed the visual perception of human by EEG signal analysis. We also have obtained that a sinusoidal grating stimulation was given, asymmetry was observed the α wave element in EEG of the symmetric part in a left hemisphere and a right hemisphere of the brain. Therefore, it is presumed that projected image is even when the still picture is seen and the image projected onto retinas of right and left eyes is not even for the dynamic scene. It evaluated it by taking the envelope curve for the detected α wave, and using the average and standard deviation.

  16. Tackling EEG signal classification with least squares support vector machines: a sensitivity analysis study.

    PubMed

    Lima, Clodoaldo A M; Coelho, André L V; Eisencraft, Marcio

    2010-08-01

    The electroencephalogram (EEG) signal captures the electrical activity of the brain and is an important source of information for studying neurological disorders. The proper analysis of this biological signal plays an important role in the domain of brain-computer interface, which aims at the construction of communication channels between human brain and computers. In this paper, we investigate the application of least squares support vector machines (LS-SVM) to the task of epilepsy diagnosis through automatic EEG signal classification. More specifically, we present a sensitivity analysis study by means of which the performance levels exhibited by standard and least squares SVM classifiers are contrasted, taking into account the setting of the kernel function and of its parameter value. Results of experiments conducted over different types of features extracted from a benchmark EEG signal dataset evidence that the sensitivity profiles of the kernel machines are qualitatively similar, both showing notable performance in terms of accuracy and generalization. In addition, the performance accomplished by optimally configured LS-SVM models is also quantitatively contrasted with that obtained by related approaches for the same dataset. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. From lab to field conditions: a pilot study on EEG methodology in applied sports sciences.

    PubMed

    Reinecke, Kirsten; Cordes, Marjolijn; Lerch, Christiane; Koutsandréou, Flora; Schubert, Michael; Weiss, Michael; Baumeister, Jochen

    2011-12-01

    Although neurophysiological aspects have become more important in sports and exercise sciences in the last years, it was not possible to measure cortical activity during performance outside a laboratory due to equipment limits or movement artifacts in particular. With this pilot study we want to investigate whether Electroencephalography (EEG) data obtained in a laboratory golf putting performance differ from a suitable putting task under field conditions. Therefore, parameters of the working memory (frontal Theta and parietal Alpha 2 power) were recorded during these two conditions. Statistical calculations demonstrated a significant difference only for Theta power at F4 regarding the two putting conditions "field" and "laboratory". These findings support the idea that brain activity patterns obtained under laboratory conditions are comparable but not equivalent to those obtained under field conditions. Additionally, we were able to show that the EEG methodology seems to be a reliable tool to observe brain activity under field conditions in a golf putting task. However, considering the still existing problems of movement artifacts during EEG measurements, eligible sports and exercises are limited to those being relatively motionless during execution. Further studies are needed to confirm these pilot results.

  18. Epilepsy in ring 14 syndrome: a clinical and EEG study of 22 patients.

    PubMed

    Giovannini, Simona; Marangio, Lucia; Fusco, Carlo; Scarano, Angela; Frattini, Daniele; Della Giustina, Elvio; Zollino, Marcella; Neri, Giovanni; Gobbi, Giuseppe

    2013-12-01

    To characterize epileptic phenotype, electroencephalography (EEG) features, and epileptic evolution in patients with ring 14 r(14) syndrome. Twenty-two patients with ring chromosome 14 were enrolled in the study. We examined age at onset, seizure semiology and frequency at onset and at follow-up, drug responsiveness/resistance, and interictal/ictal EEG data. The degree of severity of the epileptic phenotype negatively influences child cognitive development. The incidence of epilepsy in patients with r(14) syndrome is virtually 100%, characterized by early onset, polymorphic seizures, and drug-resistant seizures. In addition, we ascertained focal secondarily generalized epilepsy, seizure cluster tendency, frequent status epilepticus, and a rather typical epilepsy evolution. EEG abnormalities consisted of slow background activity with pseudoperiodic bursts of generalized slow waves in the early stage, focal frontotemporal or temporoposterior slow waves with multifocal spikes interposed, and unusual rhythmic fast recruiting posterior spikes followed by secondary generalization. The degree of severity of the epileptic phenotype negatively influences child cognitive development. This study provides a more precise definition of seizure types, natural history, and drug responsiveness of r(14) syndrome, a highly epileptogenic chromosomal condition. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

  19. Neural processing of emotions in traumatized children treated with Eye Movement Desensitization and Reprocessing therapy: a hdEEG study

    PubMed Central

    Trentini, Cristina; Pagani, Marco; Fania, Piercarlo; Speranza, Anna Maria; Nicolais, Giampaolo; Sibilia, Alessandra; Inguscio, Lucio; Verardo, Anna Rita; Fernandez, Isabel; Ammaniti, Massimo

    2015-01-01

    Eye Movement Desensitization and Reprocessing (EMDR) therapy has been proven efficacious in restoring affective regulation in post-traumatic stress disorder (PTSD) patients. However, its effectiveness on emotion processing in children with complex trauma has yet to be explored. High density electroencephalography (hdEEG) was used to investigate the effects of EMDR on brain responses to adults’ emotions on children with histories of early maltreatment. Ten school-aged children were examined before (T0) and within one month after the conclusion of EMDR (T1). hdEEGs were recorded while children passively viewed angry, afraid, happy, and neutral faces. Clinical scales were administered at the same time. Correlation analyses were performed to detect brain regions whose activity was linked to children’s traumatic symptom-related and emotional-adaptive problem scores. In all four conditions, hdEEG showed similar significantly higher activity on the right medial prefrontal and fronto-temporal limbic regions at T0, shifting toward the left medial and superior temporal regions at T1. Moreover, significant correlations were found between clinical scales and the same regions whose activity significantly differed between pre- and post-treatment. These preliminary results demonstrate that, after EMDR, children suffering from complex trauma show increased activity in areas implicated in high-order cognitive processing when passively viewing pictures of emotional expressions. These changes are associated with the decrease of depressive and traumatic symptoms, and with the improvement of emotional-adaptive functioning over time. PMID:26594183

  20. Neural processing of emotions in traumatized children treated with Eye Movement Desensitization and Reprocessing therapy: a hdEEG study.

    PubMed

    Trentini, Cristina; Pagani, Marco; Fania, Piercarlo; Speranza, Anna Maria; Nicolais, Giampaolo; Sibilia, Alessandra; Inguscio, Lucio; Verardo, Anna Rita; Fernandez, Isabel; Ammaniti, Massimo

    2015-01-01

    Eye Movement Desensitization and Reprocessing (EMDR) therapy has been proven efficacious in restoring affective regulation in post-traumatic stress disorder (PTSD) patients. However, its effectiveness on emotion processing in children with complex trauma has yet to be explored. High density electroencephalography (hdEEG) was used to investigate the effects of EMDR on brain responses to adults' emotions on children with histories of early maltreatment. Ten school-aged children were examined before (T0) and within one month after the conclusion of EMDR (T1). hdEEGs were recorded while children passively viewed angry, afraid, happy, and neutral faces. Clinical scales were administered at the same time. Correlation analyses were performed to detect brain regions whose activity was linked to children's traumatic symptom-related and emotional-adaptive problem scores. In all four conditions, hdEEG showed similar significantly higher activity on the right medial prefrontal and fronto-temporal limbic regions at T0, shifting toward the left medial and superior temporal regions at T1. Moreover, significant correlations were found between clinical scales and the same regions whose activity significantly differed between pre- and post-treatment. These preliminary results demonstrate that, after EMDR, children suffering from complex trauma show increased activity in areas implicated in high-order cognitive processing when passively viewing pictures of emotional expressions. These changes are associated with the decrease of depressive and traumatic symptoms, and with the improvement of emotional-adaptive functioning over time.

  1. High-density electroencephalographic recordings during sleep in children with disorders of consciousness.

    PubMed

    Mouthon, Anne-Laure; van Hedel, Hubertus J A; Meyer-Heim, Andreas; Kurth, Salome; Ringli, Maya; Pugin, Fiona; Huber, Reto

    2016-01-01

    A large number of studies have investigated neural correlates of consciousness in adults. However, knowledge about brain function in children with disorders of consciousness (DOC) is very limited. We suggest that EEG recordings during sleep are a promising approach. In healthy adults as well as in children, it has been shown that the activity of sleep slow waves (EEG spectral power 1-4.5 Hz), the primary characteristic of deep sleep, is dependent on use during previous wakefulness. Thus the regulation of slow wave activity (SWA) provides indirect insights into brain function during wakefulness. In the present study, we investigated high-density EEG recordings during sleep in ten healthy children and in ten children with acquired brain injury, including five children with DOC and five children with acquired brain injury without DOC. We used the build-up of SWA to quantify SWA regulation. Children with DOC showed a global reduction in the SWA build-up when compared to both, healthy children and children with acquired brain injury without DOC. This reduction was most pronounced over parietal brain areas. Comparisons within the group of children with DOC revealed that the parietal SWA build-up was the lowest in patients showing poor outcome. Longitudinal measurements during the recovery period showed an increase in parietal SWA build-up from the first to the second sleep recording. Our results suggest that the reduced parietal SWA regulation may represent a characteristic topographical marker for brain network dysfunction in children with DOC. In the future, the regulation of SWA might be used as a complementary assessment in adult and paediatric patients with DOC.

  2. High-density electroencephalographic recordings during sleep in children with disorders of consciousness

    PubMed Central

    Mouthon, Anne-Laure; van Hedel, Hubertus J.A.; Meyer-Heim, Andreas; Kurth, Salome; Ringli, Maya; Pugin, Fiona; Huber, Reto

    2016-01-01

    Introduction A large number of studies have investigated neural correlates of consciousness in adults. However, knowledge about brain function in children with disorders of consciousness (DOC) is very limited. We suggest that EEG recordings during sleep are a promising approach. In healthy adults as well as in children, it has been shown that the activity of sleep slow waves (EEG spectral power 1–4.5 Hz), the primary characteristic of deep sleep, is dependent on use during previous wakefulness. Thus the regulation of slow wave activity (SWA) provides indirect insights into brain function during wakefulness. Methods In the present study, we investigated high-density EEG recordings during sleep in ten healthy children and in ten children with acquired brain injury, including five children with DOC and five children with acquired brain injury without DOC. We used the build-up of SWA to quantify SWA regulation. Results Children with DOC showed a global reduction in the SWA build-up when compared to both, healthy children and children with acquired brain injury without DOC. This reduction was most pronounced over parietal brain areas. Comparisons within the group of children with DOC revealed that the parietal SWA build-up was the lowest in patients showing poor outcome. Longitudinal measurements during the recovery period showed an increase in parietal SWA build-up from the first to the second sleep recording. Conclusions Our results suggest that the reduced parietal SWA regulation may represent a characteristic topographical marker for brain network dysfunction in children with DOC. In the future, the regulation of SWA might be used as a complementary assessment in adult and paediatric patients with DOC. PMID:27104141

  3. Anticipatory attentional suppression of visual features indexed by oscillatory alpha-band power increases: a high-density electrical mapping study.

    PubMed

    Snyder, Adam C; Foxe, John J

    2010-03-17

    Retinotopically specific increases in alpha-band ( approximately 10 Hz) oscillatory power have been strongly implicated in the suppression of processing for irrelevant parts of the visual field during the deployment of visuospatial attention. Here, we asked whether this alpha suppression mechanism also plays a role in the nonspatial anticipatory biasing of feature-based attention. Visual word cues informed subjects what the task-relevant feature of an upcoming visual stimulus (S2) was, while high-density electroencephalographic recordings were acquired. We examined anticipatory oscillatory activity in the Cue-to-S2 interval ( approximately 2 s). Subjects were cued on a trial-by-trial basis to attend to either the color or direction of motion of an upcoming dot field array, and to respond when they detected that a subset of the dots differed from the majority along the target feature dimension. We used the features of color and motion, expressly because they have well known, spatially separated cortical processing areas, to distinguish shifts in alpha power over areas processing each feature. Alpha power from dorsal regions increased when motion was the irrelevant feature (i.e., color was cued), and alpha power from ventral regions increased when color was irrelevant. Thus, alpha-suppression mechanisms appear to operate during feature-based selection in much the same manner as has been shown for space-based attention.

  4. A comparative study on different ionic liquids used as surfactants: Effect on thermal and mechanical properties of high-density polyethylene nanocomposites.

    PubMed

    Livi, Sébastien; Duchet-Rumeau, Jannick; Pham, Thi-Nhàn; Gérard, Jean-François

    2010-09-01

    Dialkyl imidazolium and alkyl phosphonium salts were synthesized to be used as new surfactants for cationic exchange of layered silicates, such as montmorillonite (MMT). The synthesized phosphonium (P-MMT) or imidazolium ion (I-MMT)-modified montmorillonites display a dramatically improved thermal degradation with respect to commonly used quaternary ammonium salts. This thermal degradation window can still be shifted toward higher temperatures after washing of modified clays. Two kinds of organic species can be identified onto clay: physically adsorbed species versus chemically adsorbed species. To evidence the impact of these thermally resistant ionic liquids, the modified montmorillonites were introduced in a great commodity polymer, i.e., high-density polyethylene. Thermoplastic nanocomposites with a very low amount of nanofillers were processed in melt by twin screw extrusion. If the thermal stability of polyethylene is slightly increased with only 2wt.% of thermostable made clays, the stiffness-toughness compromise is well improved since a strong increase in modulus is achieved with both thermostable clays without loss of fracture properties. But these mechanical performances are mainly obtained with unwashed thermostable clays because the physically adsorbed organic species onto clay surfaces behave like a compatibilizer that helps both the dispersion into the PE matrix and improves the clay/matrix interface quality. Copyright 2009. Published by Elsevier Inc.

  5. [Comparative study on EEG and neuroimaging of patients with cerebral cysticercosis before and after treatment].

    PubMed

    Wang, Zhong-lei; Fu, Ting-xia; Hu, Ying-xin; Li, Gui-ling; Mao, De-hua; Tan, Wen-bin

    2014-06-01

    To study the changes of cerebral function and pathological morphology before and after the antiparasitic treatment with albendazole and praziquantel in patients with cerebral cysticercosis. The data of EEG and neuroimaging of 412 patients with cerebral cysticercosis were retrospectively analyzed. Before the treatment, the mild abnormality, moderate abnormality, and severe abnormality were observed in 40.53%, 45.63% and 13.84% of the patients respectively, which mainly showed the diffuse or focal irregular slow waves, or epileptiform discharges found in the abnormal brain waves. CT/MRI manifestation could be divided into six types, including single sacculus type (23.59%), multiple sacculus type (44.42%), encephalitis type (13.59%), coexistence of macrocyst and sacculus type (4.85%), calcification type (2.18%), and mixed type (11.41%). After 3 courses of the treatment, the normal and improved EEGs were observed in 79.85% and 20.15%, respectively. CT/MRI showed the foci being all absorbed (77.18%), being most absorbed (20.63%), and being no changes (20.18%) which were calcified focus. When cerebral cysticercosis were in acute stage (the single and multiple sacculus type, encephalitis type, and macrocyst and sacculus coexistence type), the therapeutic effect was good; while in the mixed type, the therapeutic effect was relatively poor. If cysticercosis were in the calcification stage, the patients only needed the heteropathy. In the patients with cerebral cysticercosis, EEGs show the mild to severe abnormalities, and CT/MRI mainly shows the multiple sacculus type. After the treatment, the abnormal EEGs are gradually recovered and the low density foci can be all absorbed, but some calcified focus still exist in some patients.

  6. A critical assessment of connectivity measures for EEG data: a simulation study.

    PubMed

    Haufe, Stefan; Nikulin, Vadim V; Müller, Klaus-Robert; Nolte, Guido

    2013-01-01

    Information flow between brain areas is difficult to estimate from EEG measurements due to the presence of noise as well as due to volume conduction. We here test the ability of popular measures of effective connectivity to detect an underlying neuronal interaction from simulated EEG data, as well as the ability of commonly used inverse source reconstruction techniques to improve the connectivity estimation. We find that volume conduction severely limits the neurophysiological interpretability of sensor-space connectivity analyses. Moreover, it may generally lead to conflicting results depending on the connectivity measure and statistical testing approach used. In particular, we note that the application of Granger-causal (GC) measures combined with standard significance testing leads to the detection of spurious connectivity regardless of whether the analysis is performed on sensor-space data or on sources estimated using three different established inverse methods. This empirical result follows from the definition of GC. The phase-slope index (PSI) does not suffer from this theoretical limitation and therefore performs well on our simulated data. We develop a theoretical framework to characterize artifacts of volume conduction, which may still be present even in reconstructed source time series as zero-lag correlations, and to distinguish their time-delayed brain interaction. Based on this theory we derive a procedure which suppresses the influence of volume conduction, but preserves effects related to time-lagged brain interaction in connectivity estimates. This is achieved by using time-reversed data as surrogates for statistical testing. We demonstrate that this robustification makes Granger-causal connectivity measures applicable to EEG data, achieving similar results as PSI. Integrating the insights of our study, we provide a guidance for measuring brain interaction from EEG data. Software for generating benchmark data is made available. Copyright © 2012

  7. Different modalities of painful somatosensory stimulations affect anticipatory cortical processes: a high-resolution EEG study.

    PubMed

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

    2007-03-15

    Pain sensation is characterized by multiple features that allow to differentiate pricking, burning, aching, stinging, and electrical shock. These features are sub-served by neural pathways that might give flexibility and selectivity to the cerebral anticipatory processes. In this line, the present high-resolution electroencephalography (EEG) study tested the hypothesis that the anticipatory cortical processes are stronger for painful thermal (biologically relevant) than electrical ("artificial") stimuli with similar intensity. EEG data (128 electrodes) were recorded in normal subjects during the expectancy of painful electrical or laser stimuli (visual omitted stimulus paradigm; interval between two painful stimuli: 16s), delivered over the median nerve region of the right arm (nonpainful stimuli as controls). After each stimulus, the subject reported the perceived stimulus intensity. Surface Laplacian estimation of the EEG data spatially enhanced the anticipatory stimulus-preceding negativity (SPN), which reflects motivational relevance of the stimulus. Subjects perceived no difference in the intensity of the electrical versus laser stimuli in both painful and nonpainful conditions. However, the anticipatory SPN appeared over large scalp regions before painful laser but not electrical stimulation. The same was true for the nonpainful stimulations. The present results suggest that the motivational anticipatory cortical processes are induced by nonpainful and painful biologically/ecologically relevant laser stimuli rather than by "artificial" electrical stimuli with similar intensity.

  8. Study of heart-brain interactions through EEG, ECG, and emotions

    NASA Astrophysics Data System (ADS)

    Ramasamy, Mouli; Varadan, Vijay K.

    2017-04-01

    Neurocardiology is the exploration of neurophysiological, neurological and neuroanatomical facets of neuroscience's influence in cardiology. The paraphernalia of emotions on the heart and brain are premeditated because of the interaction between the central and peripheral nervous system. This is an investigative attempt to study emotion based neurocardiology and the factors that influence this phenomenon. The factors include: interaction between sleep EEG (electroencephalogram) and ECG (electrocardiogram), relationship between emotion and music, psychophysiological coherence between the heart and brain, emotion recognition techniques, and biofeedback mechanisms. Emotions contribute vitally to the mundane life and are quintessential to a numerous biological and everyday-functional modality of a human being. Emotions are best represented through EEG signals, and to a certain extent, can be observed through ECG and body temperature. Confluence of medical and engineering science has enabled the monitoring and discrimination of emotions influenced by happiness, anxiety, distress, excitement and several other factors that influence the thinking patterns and the electrical activity of the brain. Similarly, HRV (Heart Rate Variability) widely investigated for its provision and discerning characteristics towards EEG and the perception in neurocardiology.

  9. Category-Selectivity in Human Visual Cortex Follows Cortical Topology: A Grouped icEEG Study

    PubMed Central

    Conner, Christopher Richard; Whaley, Meagan Lee; Baboyan, Vatche George; Tandon, Nitin

    2016-01-01

    Neuroimaging studies suggest that category-selective regions in higher-order visual cortex are topologically organized around specific anatomical landmarks: the mid-fusiform sulcus (MFS) in the ventral temporal cortex (VTC) and lateral occipital sulcus (LOS) in the lateral occipital cortex (LOC). To derive precise structure-function maps from direct neural signals, we collected intracranial EEG (icEEG) recordings in a large human cohort (n = 26) undergoing implantation of subdural electrodes. A surface-based approach to grouped icEEG analysis was used to overcome challenges from sparse electrode coverage within subjects and variable cortical anatomy across subjects. The topology of category-selectivity in bilateral VTC and LOC was assessed for five classes of visual stimuli—faces, animate non-face (animals/body-parts), places, tools, and words—using correlational and linear mixed effects analyses. In the LOC, selectivity for living (faces and animate non-face) and non-living (places and tools) classes was arranged in a ventral-to-dorsal axis along the LOS. In the VTC, selectivity for living and non-living stimuli was arranged in a latero-medial axis along the MFS. Written word-selectivity was reliably localized to the intersection of the left MFS and the occipito-temporal sulcus. These findings provide direct electrophysiological evidence for topological information structuring of functional representations within higher-order visual cortex. PMID:27272936

  10. EEG-fMRI Study of Alpha-Stimulation Neurobiofeedback Training Course.

    PubMed

    Kozlova, L I; Shtark, M B; Mel'nikov, M E; Verevkin, E G; Savelov, A A; Petrovskii, E D

    2016-09-01

    fMRI-EEG dynamics of brain activity in volunteers was studied during the course of EEG alpha-stimulation training (20 sessions). Twenty-three healthy men (20-35 years) were subjected to 3-fold mapping in a feedback loop (EEG alpha-rhythm biofeedback with acoustic reinforcement). This procedure was performed at the beginning, middle, and end of the course. During the first neurofeedback training session, deactivation (p<0.001) was found in the right angular gyrus, supramarginal, and superior temporal gyri, Brodmann area 39, and cerebellum. Activation (p<0.001) was observed in the medial frontal and cingulate gyri, motor areas of both hemispheres, and Brodmann area 32. During final (third) neurofeedback training session, we observed strong deactivation (p<0.05 with FDR) of zones responsible for spatial thinking and motor functions: left medial frontal and left medial temporal gyri; right postcentral, lingual, and superior frontal gyri; insula and right side of the cerebellum; and precuneus and cuneus (Brodmann areas 6, 9, 7, 31, 8, 13, and 22). Changes in the alpha wave power were most pronounced in the primary and secondary somatosensory cortex of the left hemisphere (Brodmann areas 2L and 5L).

  11. Decoding the attended speech stream with multi-channel EEG: implications for online, daily-life applications

    NASA Astrophysics Data System (ADS)

    Mirkovic, Bojana; Debener, Stefan; Jaeger, Manuela; De Vos, Maarten

    2015-08-01

    Objective. Recent studies have provided evidence that temporal envelope driven speech decoding from high-density electroencephalography (EEG) and magnetoencephalography recordings can identify the attended speech stream in a multi-speaker scenario. The present work replicated the previous high density EEG study and investigated the necessary technical requirements for practical attended speech decoding with EEG. Approach. Twelve normal hearing participants attended to one out of two simultaneously presented audiobook stories, while high density EEG was recorded. An offline iterative procedure eliminating those channels contributing the least to decoding provided insight into the necessary channel number and optimal cross-subject channel configuration. Aiming towards the future goal of near real-time classification with an individually trained decoder, the minimum duration of training data necessary for successful classification was determined by using a chronological cross-validation approach. Main results. Close replication of the previously reported results confirmed the method robustness. Decoder performance remained stable from 96 channels down to 25. Furthermore, for less than 15 min of training data, the subject-independent (pre-trained) decoder performed better than an individually trained decoder did. Significance. Our study complements previous research and provides information suggesting that efficient low-density EEG online decoding is within reach.

  12. Relationship of EEG sources of neonatal seizures to acute perinatal brain lesions seen on MRI: a pilot study.

    PubMed

    Despotovic, Ivana; Cherian, Perumpillichira J; De Vos, Maarten; Hallez, Hans; Deburchgraeve, Wouter; Govaert, Paul; Lequin, Maarten; Visser, Gerhard H; Swarte, Renate M; Vansteenkiste, Ewout; Van Huffel, Sabine; Philips, Wilfried

    2013-10-01

    Even though it is known that neonatal seizures are associated with acute brain lesions, the relationship of electroencephalographic (EEG) seizures to acute perinatal brain lesions visible on magnetic resonance imaging (MRI) has not been objectively studied. EEG source localization is successfully used for this purpose in adults, but it has not been sufficiently explored in neonates. Therefore, we developed an integrated method for ictal EEG dipole source localization based on a realistic head model to investigate the utility of EEG source imaging in neonates with postasphyxial seizures. We describe here our method and compare the dipole seizure localization results with acute perinatal lesions seen on brain MRI in 10 full-term infants with neonatal encephalopathy. Through experimental studies, we also explore the sensitivity of our method to the electrode positioning errors and the variations in neonatal skull geometry and conductivity. The localization results of 45 focal seizures from 10 neonates are compared with the visual analysis of EEG and MRI data, scored by expert physicians. In 9 of 10 neonates, dipole locations showed good relationship with MRI lesions and clinical data. Our experimental results also suggest that the variations in the used values for skull conductivity or thickness have little effect on the dipole localization, whereas inaccurate electrode positioning can reduce the accuracy of source estimates. The performance of our fused method indicates that ictal EEG source imaging is feasible in neonates and with further validation studies, this technique can become a useful diagnostic tool.

  13. Quantitative EEG and its Correlation with Cardiovascular, Cognition and mood State: an Integrated Study in Simulated Microgravity

    NASA Astrophysics Data System (ADS)

    Zhang, Jianyuan; Hu, Bin; Chen, Wenjuan; Moore, Philip; Xu, Tingting; Dong, Qunxi; Liu, Zhenyu; Luo, Yuejia; Chen, Shanguang

    2014-12-01

    The focus of the study is the estimation of the effects of microgravity on the central nervous activity and its underlying influencing mechanisms. To validate the microgravity-induced physiological and psychological effects on EEG, quantitative EEG features, cardiovascular indicators, mood state, and cognitive performances data collection was achieved during a 45 day period using a -6°head-down bed rest (HDBR) integrated approach. The results demonstrated significant differences in EEG data, as an increased Theta wave, a decreased Beta wave and a reduced complexity of brain, accompanied with an increased heart rate and pulse rate, decreased positive emotion, and degraded emotion conflict monitoring performance. The canonical correlation analysis (CCA) based cardiovascular and cognitive related EEG model showed the cardiovascular effect on EEG mainly affected bilateral temporal region and the cognitive effect impacted parietal-occipital and frontal regions. The results obtained in the study support the use of an approach which combines a multi-factor influential mechanism hypothesis. The changes in the EEG data may be influenced by both cardiovascular and cognitive effects.

  14. Prevalence of High Non-high-density Lipoprotein Cholesterol and Associated Risk Factors in Patients with Diabetes Mellitus in Jilin Province, China: A Cross-sectional Study.

    PubMed

    He, Huan; Zhen, Qing; Li, Yong; Kou, Chang Gui; Tao, Yu Chun; Wang, Chang; Kanu, Joseph Sam; Lu, Yu Ping; Yu, Ming Xi; Zhang, Hui Ping; Yu, Ya Qin; Li, Bo; Liu, Ya Wen

    2016-07-01

    Dyslipidemia is a risk factor for cardiovascular diseases (CVDs) in patients with diabetes, and non-high-density lipoprotein cholesterol (non-HDL-C) is a better predictor of CVDs than low-density lipoprotein cholesterol (LDL-C) in patients with diabetes. Therefore, we aimed to investigate the distribution of non-HDL-C and the prevalence of high non-HDL-C level in Chinese patients with diabetes mellitus and identify the associated risk factors. Non-HDL-C concentration positively correlated with total cholesterol, triglycerides, and LDL-C concentrations. Although both non-HDL-C and LDL-C concentration both related positively with TC concentration, the magnitude of correlation was relatively higher for non-HDL-C. The prevalence of high non-HDL-C (⋝4.14 mmol/L) was higher in two age groups (55-64 years: 46.7%; 65-79 years: 47.3%) than other age groups (18-24 years: 4.2%; 25-34 years: 43.6%; 35-44 years: 38.1%; 45-54 years: 41.0%). It was also higher among overweight (45.1%), generally obese (50.9%), or abdominally obese (47.3%) subjects, compared with normal weight subjects (34.5%). The risk of high non-HDL-C increased with advancing age. Both general obesity [odds ratio (OR)=1.488, 95% confidence interval (CI): 1.003-2.209] and abdominal obesity (OR=1.561, 95% CI: 1.101-2.214) were significantly associated with high non-HDL-C levels. Copyright © 2016 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  15. Genome-wide association study using high-density single nucleotide polymorphism arrays and whole-genome sequences for clinical mastitis traits in dairy cattle.

    PubMed

    Sahana, G; Guldbrandtsen, B; Thomsen, B; Holm, L-E; Panitz, F; Brøndum, R F; Bendixen, C; Lund, M S

    2014-11-01

    Mastitis is a mammary disease that frequently affects dairy cattle. Despite considerable research on the development of effective prevention and treatment strategies, mastitis continues to be a significant issue in bovine veterinary medicine. To identify major genes that affect mastitis in dairy cattle, 6 chromosomal regions on Bos taurus autosome (BTA) 6, 13, 16, 19, and 20 were selected from a genome scan for 9 mastitis phenotypes using imputed high-density single nucleotide polymorphism arrays. Association analyses using sequence-level variants for the 6 targeted regions were carried out to map causal variants using whole-genome sequence data from 3 breeds. The quantitative trait loci (QTL) discovery population comprised 4,992 progeny-tested Holstein bulls, and QTL were confirmed in 4,442 Nordic Red and 1,126 Jersey cattle. The targeted regions were imputed to the sequence level. The highest association signal for clinical mastitis was observed on BTA 6 at 88.97 Mb in Holstein cattle and was confirmed in Nordic Red cattle. The peak association region on BTA 6 contained 2 genes: vitamin D-binding protein precursor (GC) and neuropeptide FF receptor 2 (NPFFR2), which, based on known biological functions, are good candidates for affecting mastitis. However, strong linkage disequilibrium in this region prevented conclusive determination of the causal gene. A different QTL on BTA 6 located at 88.32 Mb in Holstein cattle affected mastitis. In addition, QTL on BTA 13 and 19 were confirmed to segregate in Nordic Red cattle and QTL on BTA 16 and 20 were confirmed in Jersey cattle. Although several candidate genes were identified in these targeted regions, it was not possible to identify a gene or polymorphism as the causal factor for any of these regions. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Assessing the Driver’s Current Level of Working Memory Load with High Density Functional Near-infrared Spectroscopy: A Realistic Driving Simulator Study

    PubMed Central

    Unni, Anirudh; Ihme, Klas; Jipp, Meike; Rieger, Jochem W.

    2017-01-01

    Cognitive overload or underload results in a decrease in human performance which may result in fatal incidents while driving. We envision that driver assistive systems which adapt their functionality to the driver’s cognitive state could be a promising approach to reduce road accidents due to human errors. This research attempts to predict variations of cognitive working memory load levels in a natural driving scenario with multiple parallel tasks and to reveal predictive brain areas. We used a modified version of the n-back task to induce five different working memory load levels (from 0-back up to 4-back) forcing the participants to continuously update, memorize, and recall the previous ‘n’ speed sequences and adjust their speed accordingly while they drove for approximately 60 min on a highway with concurrent traffic in a virtual reality driving simulator. We measured brain activation using multichannel whole head, high density functional near-infrared spectroscopy (fNIRS) and predicted working memory load level from the fNIRS data by combining multivariate lasso regression and cross-validation. This allowed us to predict variations in working memory load in a continuous time-resolved manner with mean Pearson correlations between induced and predicted working memory load over 15 participants of 0.61 [standard error (SE) 0.04] and a maximum of 0.8. Restricting the analysis to prefrontal sensors placed over the forehead reduced the mean correlation to 0.38 (SE 0.04), indicating additional information gained through whole head coverage. Moreover, working memory load predictions derived from peripheral heart rate parameters achieved much lower correlations (mean 0.21, SE 0.1). Importantly, whole head fNIRS sampling revealed increasing brain activation in bilateral inferior frontal and bilateral temporo-occipital brain areas with increasing working memory load levels suggesting that these areas are specifically involved in workload-related processing. PMID

  17. Fluid hydrogen at high density - Pressure dissociation

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1991-01-01

    A model for the Helmholtz free energy of fluid hydrogen at high density and high temperature is developed. This model aims at describing both pressure and temperature dissociation and ionization and bears directly on equations of state of partially ionized plasmas, as encountered in astrophysical situations and high-pressure experiments. This paper focuses on a mixture of hydrogen atoms and molecules and is devoted to the study of the phenomenon of pressure dissociation at finite temperatures. In the present model, the strong interactions are described with realistic potentials and are computed with a modified Weeks-Chandler-Andersen fluid perturbation theory that reproduces Monte Carlo simulations to better than 3 percent. Theoretical Hugoniot curves derived from the model are in excellent agreement with experimental data.

  18. Fluid hydrogen at high density - Pressure dissociation

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1991-01-01

    A model for the Helmholtz free energy of fluid hydrogen at high density and high temperature is developed. This model aims at describing both pressure and temperature dissociation and ionization and bears directly on equations of state of partially ionized plasmas, as encountered in astrophysical situations and high-pressure experiments. This paper focuses on a mixture of hydrogen atoms and molecules and is devoted to the study of the phenomenon of pressure dissociation at finite temperatures. In the present model, the strong interactions are described with realistic potentials and are computed with a modified Weeks-Chandler-Andersen fluid perturbation theory that reproduces Monte Carlo simulations to better than 3 percent. Theoretical Hugoniot curves derived from the model are in excellent agreement with experimental data.

  19. Structures of High Density Molecular Fluids

    SciTech Connect

    Baer, B; Cynn, H; Iota, V; Yoo, C-S

    2002-02-01

    The goal of this proposal is to develop an in-situ probe for high density molecular fluids. We will, therefore, use Coherent Anti-Stokes Raman Spectroscopy (CARS) applied to laser heated samples in a diamond-anvil cell (DAC) to investigate molecular fluids at simultaneous conditions of high temperatures (T > 2000K) and high pressures (P > 10 GPa.) Temperatures sufficient to populate vibrational levels above the ground state will allow the vibrational potential to be mapped by CARS. A system capable of heating and probing these samples will be constructed. Furthermore, the techniques that enable a sample to be sufficiently heated and probed while held at static high pressure in a diamond-anvil-cell will be developed. This will be an in-situ investigation of simple molecules under conditions relevant to the study of detonation chemistry and the Jovain planet interiors using state of the art non-linear spectroscopy, diamond-anvil-cells, and laser heating technology.

  20. Association between plasma triglycerides and high-density lipoprotein cholesterol and microvascular kidney disease and retinopathy in type 2 diabetes mellitus: a global case-control study in 13 countries.

    PubMed

    Sacks, Frank M; Hermans, Michel P; Fioretto, Paola; Valensi, Paul; Davis, Timothy; Horton, Edward; Wanner, Christoph; Al-Rubeaan, Khalid; Aronson, Ronnie; Barzon, Isabella; Bishop, Louise; Bonora, Enzo; Bunnag, Pongamorn; Chuang, Lee-Ming; Deerochanawong, Chaicharn; Goldenberg, Ronald; Harshfield, Benjamin; Hernández, Cristina; Herzlinger-Botein, Susan; Itoh, Hiroshi; Jia, Weiping; Jiang, Yi-Der; Kadowaki, Takashi; Laranjo, Nancy; Leiter, Lawrence; Miwa, Takashi; Odawara, Masato; Ohashi, Ken; Ohno, Atsushi; Pan, Changyu; Pan, Jiemin; Pedro-Botet, Juan; Reiner, Zeljko; Rotella, Carlo Maria; Simo, Rafael; Tanaka, Masami; Tedeschi-Reiner, Eugenia; Twum-Barima, David; Zoppini, Giacomo; Carey, Vincent J

    2014-03-04

    Microvascular renal and retinal diseases are common major complications of type 2 diabetes mellitus. The relation between plasma lipids and microvascular disease is not well established. The case subjects were 2535 patients with type 2 diabetes mellitus with an average duration of 14 years, 1891 of whom had kidney disease and 1218 with retinopathy. The case subjects were matched for diabetes mellitus duration, age, sex, and low-density lipoprotein cholesterol to 3683 control subjects with type 2 diabetes mellitus who did not have kidney disease or retinopathy. The study was conducted in 24 sites in 13 countries. The primary analysis included kidney disease and retinopathy cases. Matched analysis was performed by use of site-specific conditional logistic regression in multivariable models that adjusted for hemoglobin A1c, hypertension, and statin treatment. Mean low-density lipoprotein cholesterol concentration was 2.3 mmol/L. The microvascular disease odds ratio increased by a factor of 1.16 (95% confidence interval, 1.11-1.22) for every 0.5 mmol/L (≈1 quintile) increase in triglycerides or decreased by a factor of 0.92 (0.88-0.96) for every 0.2 mmol/L (≈1 quintile) increase in high-density lipoprotein cholesterol. For kidney disease, the odds ratio increased by 1.23 (1.16-1.31) with triglycerides and decreased by 0.86 (0.82-0.91) with high-density lipoprotein cholesterol. Retinopathy was associated with triglycerides and high-density lipoprotein cholesterol in matched analysis but not significantly after additional adjustment. Diabetic kidney disease is associated worldwide with higher levels of plasma triglycerides and lower levels of high-density lipoprotein cholesterol among patients with good control of low-density lipoprotein cholesterol. Retinopathy was less robustly associated with these lipids. These results strengthen the rationale for studying dyslipidemia treatment to prevent diabetic microvascular disease.

  1. Neural correlates of non-verbal social interactions: a dual-EEG study.

    PubMed

    Ménoret, Mathilde; Varnet, Léo; Fargier, Raphaël; Cheylus, Anne; Curie, Aurore; des Portes, Vincent; Nazir, Tatjana A; Paulignan, Yves

    2014-03-01

    Successful non-verbal social interaction between human beings requires dynamic and efficient encoding of others' gestures. Our study aimed at identifying neural markers of social interaction and goal variations in a non-verbal task. For this, we recorded simultaneously the electroencephalogram from two participants (dual-EEG), an actor and an observer, and their arm/hand kinematics in a real face-to-face paradigm. The observer watched "biological actions" performed by the human actor and "non-biological actions" performed by a robot. All actions occurred within an interactive or non-interactive context depending on whether the observer had to perform a complementary action or not (e.g., the actor presents a saucer and the observer either places the corresponding cup or does nothing). We analysed the EEG signals of both participants (i.e., beta (~20 Hz) oscillations as an index of cortical motor activity and motor related potentials (MRPs)). We identified markers of social interactions by synchronising EEG to the onset of the actor's movement. Movement kinematics did not differ in the two context conditions and the MRPs of the actor were similar in the two conditions. For the observer, however, an observation-related MRP was measured in all conditions but was more negative in the interactive context over fronto-central electrodes. Moreover, this feature was specific to biological actions. Concurrently, the suppression of beta oscillations was observed in the actor's EEG and the observer's EEG rapidly after the onset of the actor's movement. Critically, this suppression was stronger in the interactive than in the non-interactive context despite the fact that movement kinematics did not differ in the two context conditions. For the observer, this modulation was observed independently of whether the actor was a human or a robot. Our results suggest that acting in a social context induced analogous modulations of motor and sensorimotor regions in observer and actor

  2. What's behind an Inference? An EEG Study with Conditional Arguments

    ERIC Educational Resources Information Center

    Bonnefond, Mathilde; Van der Henst, Jean-Baptiste

    2009-01-01

    Conditional reasoning studies typically involve presenting a major conditional premise ("If P then Q"), a minor premise (P) and a conclusion (Q). We describe how most fMRI studies investigate reasoning and point out that these studies neglect to take into consideration the temporal sequence of cognitive steps generated by the interaction of the…

  3. What's behind an Inference? An EEG Study with Conditional Arguments

    ERIC Educational Resources Information Center

    Bonnefond, Mathilde; Van der Henst, Jean-Baptiste

    2009-01-01

    Conditional reasoning studies typically involve presenting a major conditional premise ("If P then Q"), a minor premise (P) and a conclusion (Q). We describe how most fMRI studies investigate reasoning and point out that these studies neglect to take into consideration the temporal sequence of cognitive steps generated by the interaction of the…

  4. High density harp for SSCL linac

    SciTech Connect

    Fritsche, C.T.; Krogh, M.L.; Crist, C.E.

    1993-05-01

    AlliedSignal Inc., Kansas City Division, and the Superconducting Super Collider Laboratory (SSCL) are collaboratively developing a high density harp for the SSCL linac. This harp is designed using hybrid microcircuit (HMC) technology to obtain a higher wire density than previously available. The developed harp contains one hundred twenty-eight 33-micron-diameter carbon wires on 0.38-mm centers. The harp features an onboard broken wire detection circuit. Carbon wire preparation and attachment processes were developed. High density surface mount connectors were located. The status of high density harp development will be presented along with planned future activities.

  5. Tinnitus: A Large VBM-EEG Correlational Study

    PubMed Central

    Vanneste, Sven; Van De Heyning, Paul; De Ridder, Dirk

    2015-01-01

    A surprising fact in voxel-based morphometry (VBM) studies performed in tinnitus is that not one single region is replicated in studies of different centers. The question then rises whether this is related to the low sample size of these studies, the selection of non-representative patient subgroups, or the absence of stratification according to clinical characteristics. Another possibility is that VBM is not a good tool to study functional pathologies such as tinnitus, in contrast to pathologies like Alzheimer’s disease where it is known the pathology is related to cell loss. In a large sample of 154 tinnitus patients VBM and QEEG (Quantitative Electroencephalography) was performed and evaluated by a regression analysis. Correlation analyses are performed between VBM and QEEG data. Uncorrected data demonstrated structural differences in grey matter in hippocampal and cerebellar areas related to tinnitus related distress and tinnitus duration. After control for multiple comparisons, only cerebellar VBM changes remain significantly altered. Electrophysiological differences are related to distress, tinnitus intensity, and tinnitus duration in the subgenual anterior cingulate cortex, dorsal anterior cingulate cortex, hippocampus, and parahippocampus, which confirms previous results. The absence of QEEG-VBM correlations suggest functional changes are not reflected by co-occurring structural changes in tinnitus, and the absence of VBM changes (except for the cerebellum) that survive correct statistical analysis in a large study population suggests that VBM might not be very sensitive for studying tinnitus. PMID:25781934

  6. Precaution for volume conduction in rodent cortical electroencephalography using high-density polyimide-based microelectrode arrays on the skull

    PubMed Central

    Venzi, M.; Poppendieck, W.; Hoffmann, K. P.; Åberg, E.

    2016-01-01

    In humans, significant progress has been made to link spatial changes in electroencephalographic (EEG) spectral density, connectivity strength, and phase-amplitude modulation to neurological, physiological, and psychological correlates. In contrast, standard rodent EEG techniques employ only few electrodes, which results in poor spatial resolution. Recently, a technique was developed to overcome this limitation in mice. This technique was based on a polyimide-based microelectrode (PBM) array applied on the mouse skull, maintaining a significant number of electrodes with consistent contact, electrode impedance, and mechanical stability. The present study built on this technique by extending it to rats. Therefore, a similar PBM array, but adapted to rats, was designed and fabricated. In addition, this array was connected to a wireless EEG headstage, allowing recording in untethered, freely moving rats. The advantage of a high-density array relies on the assumption that the signal recorded from the different electrodes is generated from distinct sources, i.e., not volume-conducted. Therefore, the utility and validity of the array were evaluated by determining the level of synchrony between channels due to true synchrony or volume conduction during basal vigilance states and following a subanesthetic dose of ketamine. Although the PBM array allowed recording with high signal quality, under both drug and drug-free conditions, high synchronization existed due to volume conduction between the electrodes even in the higher spectral frequency range. Discrimination existed only between frontally and centrally/distally grouped electrode pairs. Therefore, caution should be used in interpreting spatial data obtained from high-density PBM arrays in rodents. PMID:26864767

  7. Precaution for volume conduction in rodent cortical electroencephalography using high-density polyimide-based microelectrode arrays on the skull.

    PubMed

    Stienen, P J; Venzi, M; Poppendieck, W; Hoffmann, K P; Åberg, E

    2016-04-01

    In humans, significant progress has been made to link spatial changes in electroencephalographic (EEG) spectral density, connectivity strength, and phase-amplitude modulation to neurological, physiological, and psychological correlates. In contrast, standard rodent EEG techniques employ only few electrodes, which results in poor spatial resolution. Recently, a technique was developed to overcome this limitation in mice. This technique was based on a polyimide-based microelectrode (PBM) array applied on the mouse skull, maintaining a significant number of electrodes with consistent contact, electrode impedance, and mechanical stability. The present study built on this technique by extending it to rats. Therefore, a similar PBM array, but adapted to rats, was designed and fabricated. In addition, this array was connected to a wireless EEG headstage, allowing recording in untethered, freely moving rats. The advantage of a high-density array relies on the assumption that the signal recorded from the different electrodes is generated from distinct sources, i.e., not volume-conducted. Therefore, the utility and validity of the array were evaluated by determining the level of synchrony between channels due to true synchrony or volume conduction during basal vigilance states and following a subanesthetic dose of ketamine. Although the PBM array allowed recording with high signal quality, under both drug and drug-free conditions, high synchronization existed due to volume conduction between the electrodes even in the higher spectral frequency range. Discrimination existed only between frontally and centrally/distally grouped electrode pairs. Therefore, caution should be used in interpreting spatial data obtained from high-density PBM arrays in rodents. Copyright © 2016 the American Physiological Society.

  8. Usefulness of Simultaneous EEG-NIRS Recording in Language Studies

    ERIC Educational Resources Information Center

    Wallois, F.; Mahmoudzadeh, M.; Patil, A.; Grebe, R.

    2012-01-01

    One of the most challenging tasks in neuroscience in language studies, is investigation of the brain's ability to integrate and process information. This task can only be successfully addressed by applying various assessment techniques integrated into a multimodal approach. Each of these techniques has its advantages and disadvantages, but help to…

  9. Meditation States and Traits: EEG, ERP, and Neuroimaging Studies

    ERIC Educational Resources Information Center

    Cahn, B. Rael; Polich, John

    2006-01-01

    Neuroelectric and imaging studies of meditation are reviewed. Electroencephalographic measures indicate an overall slowing subsequent to meditation, with theta and alpha activation related to proficiency of practice. Sensory evoked potential assessment of concentrative meditation yields amplitude and latency changes for some components and…

  10. Meditation States and Traits: EEG, ERP, and Neuroimaging Studies

    ERIC Educational Resources Information Center

    Cahn, B. Rael; Polich, John

    2006-01-01

    Neuroelectric and imaging studies of meditation are reviewed. Electroencephalographic measures indicate an overall slowing subsequent to meditation, with theta and alpha activation related to proficiency of practice. Sensory evoked potential assessment of concentrative meditation yields amplitude and latency changes for some components and…

  11. Usefulness of Simultaneous EEG-NIRS Recording in Language Studies

    ERIC Educational Resources Information Center

    Wallois, F.; Mahmoudzadeh, M.; Patil, A.; Grebe, R.

    2012-01-01

    One of the most challenging tasks in neuroscience in language studies, is investigation of the brain's ability to integrate and process information. This task can only be successfully addressed by applying various assessment techniques integrated into a multimodal approach. Each of these techniques has its advantages and disadvantages, but help to…

  12. Meditation states and traits: EEG, ERP, and neuroimaging studies.

    PubMed

    Cahn, B Rael; Polich, John

    2006-03-01

    Neuroelectric and imaging studies of meditation are reviewed. Electroencephalographic measures indicate an overall slowing subsequent to meditation, with theta and alpha activation related to proficiency of practice. Sensory evoked potential assessment of concentrative meditation yields amplitude and latency changes for some components and practices. Cognitive event-related potential evaluation of meditation implies that practice changes attentional allocation. Neuroimaging studies indicate increased regional cerebral blood flow measures during meditation. Taken together, meditation appears to reflect changes in anterior cingulate cortex and dorsolateral prefrontal areas. Neurophysiological meditative state and trait effects are variable but are beginning to demonstrate consistent outcomes for research and clinical applications. Psychological and clinical effects of meditation are summarized, integrated, and discussed with respect to neuroimaging data.

  13. Abstract art and cortical motor activation: an EEG study

    PubMed Central

    Umilta', M. Alessandra; Berchio, Cristina; Sestito, Mariateresa; Freedberg, David; Gallese, Vittorio

    2012-01-01

    The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works. PMID:23162456

  14. Abstract art and cortical motor activation: an EEG study.

    PubMed

    Umilta', M Alessandra; Berchio, Cristina; Sestito, Mariateresa; Freedberg, David; Gallese, Vittorio

    2012-01-01

    The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works.

  15. Signal distortion from microelectrodes in clinical EEG acquisition systems

    PubMed Central

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

    2012-01-01

    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 GΩ, which is much higher than most clinical systems. These results show that it is critical to account for variations in impedance when

  16. Exploratory study of EEG burst characteristics in preterm infants.

    PubMed

    Simayijiang, Zhayida; Backman, Sofia; Ulén, Johannes; Wikström, Sverre; Åstrom, Kalle

    2013-01-01

    In this paper, we study machine learning techniques and features of electroencephalography activity bursts for predicting outcome in extremely preterm infants. It was previously shown that the distribution of interburst interval durations predicts clinical outcome, but in previous work the information within the bursts has been neglected. In this paper, we perform exploratory analysis of feature extraction of burst characteristics and use machine learning techniques to show that such features could be used for outcome prediction. The results are promising, but further verification in larger datasets is needed to obtain conclusive results.

  17. Termination Patterns of Complex Partial Seizures: An Intracranial EEG Study

    PubMed Central

    Afra, Pegah; Jouny, Christopher C.; Bergey, Gregory K.

    2015-01-01

    Purpose While seizure onset patterns have been the subject of many reports, there have been few studies of seizure termination. In this study we report the incidence of synchronous and asynchronous termination patterns of partial seizures recorded with intracranial arrays. Methods Data were collected from patients with intractable complex partial seizures undergoing presurgical evaluations with intracranial electrodes. Patients with seizures originating from mesial temporal and neocortical regions were grouped into three groups based on patterns of seizure termination: synchronous only (So), asynchronous only (Ao), or mixed (S/A, with both synchronous and asynchronous termination patterns). Results 88% of the patients in the MT group had seizures with a synchronous pattern of termination exclusively (38%) or mixed (50%). 82% of the NC group had seizures with synchronous pattern of termination exclusively (52%) or mixed (30%). In the NC group, there was a significant difference of the range of seizure durations between So and Ao groups, with Ao exhibiting higher variability. Seizures with synchronous termination had low variability in both groups. Conclusions Synchronous seizure termination is a common pattern for complex partial seizures of both mesial temporal or neocortical onset. This may reflect stereotyped network behavior or dynamics at the seizure focus. PMID:26552555

  18. Duration of complex partial seizures: an intracranial EEG study.

    PubMed

    Afra, Pegah; Jouny, Christophe C; Bergey, Gregory K

    2008-04-01

    The dynamics of partial seizures originating from neocortical and mesial temporal regions are thought to differ, yet there are no quantitative comparative studies. The studies reported here investigate the duration of complex partial seizures in these populations using analyses of seizures recorded from intracranial arrays. Data were collected from patients undergoing presurgical evaluation with intracranial electrodes. Seizure duration was defined as the time of earliest sustained ictal activity until the termination either in all electrodes (global duration, GD), or at the onset area (focal duration, FD). Patients were divided into three groups: mesial temporal lobe epilepsy (MTLE), neocortical temporal lobe epilepsy (NCTLE), and neocortical extratemporal lobe epilepsy (NCXTLE). Complex partial seizure durations were significantly longer in the MTLE group compared to the NCXTLE group. Median GD for MTLE was 106 s, and for NCXTLE was 78 s. There were no significant differences between seizure durations when comparing MTLE group to NCTLE group, or comparing NCTLE group to NCXTLE group. In the MTLE group, patients with bilateral recording arrays had significantly longer median seizure durations (GD and FD) than those sampled with unilateral arrays. In this select group of patients there is a significant difference between the duration of complex partial seizures of mesial temporal and neocortical extratemporal origin with mesial temporal complex partial seizures being longer. This may result from a number of possibilities including the bilateral propagation of some mesial temporal seizures and differences in ictal generators of the underlying networks.

  19. Termination patterns of complex partial seizures: An intracranial EEG study.

    PubMed

    Afra, Pegah; Jouny, Christopher C; Bergey, Gregory K

    2015-11-01

    While seizure onset patterns have been the subject of many reports, there have been few studies of seizure termination. In this study we report the incidence of synchronous and asynchronous termination patterns of partial seizures recorded with intracranial arrays. Data were collected from patients with intractable complex partial seizures undergoing presurgical evaluations with intracranial electrodes. Patients with seizures originating from mesial temporal and neocortical regions were grouped into three groups based on patterns of seizure termination: synchronous only (So), asynchronous only (Ao), or mixed (S/A, with both synchronous and asynchronous termination patterns). 88% of the patients in the MT group had seizures with a synchronous pattern of termination exclusively (38%) or mixed (50%). 82% of the NC group had seizures with synchronous pattern of termination exclusively (52%) or mixed (30%). In the NC group, there was a significant difference of the range of seizure durations between So and Ao groups, with Ao exhibiting higher variability. Seizures with synchronous termination had low variability in both groups. Synchronous seizure termination is a common pattern for complex partials seizures of both mesial temporal or neocortical onset. This may reflect stereotyped network behavior or dynamics at the seizure focus. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  20. High density load bearing insulation peg

    DOEpatents

    Nowobilski, J.J.; Owens, W.J.

    1985-01-29

    A high density peg is disclosed which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure. 4 figs.

  1. High density load bearing insulation peg

    DOEpatents

    Nowobilski, Jeffert J.; Owens, William J.

    1985-01-01

    A high density peg which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure.

  2. High Density Fuel Development for Research Reactors

    SciTech Connect

    Daniel Wachs; Dennis Keiser; Mitchell Meyer; Douglas Burkes; Curtis Clark; Glenn Moore; Jan-Fong Jue; Totju Totev; Gerard Hofman; Tom Wiencek; Yeon So Kim; Jim Snelgrove

    2007-09-01

    An international effort to develop, qualify, and license high and very high density fuels has been underway for several years within the framework of multi-national RERTR programs. The current development status is the result of significant contributions from many laboratories, specifically CNEA in Argentina, AECL in Canada, CEA in France, TUM in Germany, KAERI in Korea, VNIIM, RDIPE, IPPE, NCCP and RIARR in Russia, INL, ANL and Y-12 in USA. These programs are mainly engaged with UMo dispersion fuels with densities from 6 to 8 gU/cm3 (high density fuel) and UMo monolithic fuel with density as high as 16 gU/cm3 (very high density fuel). This paper, mainly focused on the French & US programs, gives the status of high density UMo fuel development and perspectives on their qualification.

  3. Treatment Effects on Neonatal EEG.

    PubMed

    Obeid, Rawad; Tsuchida, Tammy N

    2016-10-01

    Conventional EEG and amplitude-integrated electroencephalography are used in neonates to assess prognosis and significant changes in brain activity. Neuroactive medications and hypothermia can influence brain activity and therefore alter EEG interpretation. There are limited studies on the effect of these therapies on neonatal EEG background activity. Medication effects on the EEG or amplitude-integrated electroencephalography include increased interburst interval duration, voltage suppression, and sleep disruption. The effect is transient in term newborns but can be persistent in premature newborns. Although therapeutic hypothermia does not produce significant changes in EEG activity, it does change the time point at which EEG can accurately predict neurodevelopmental outcome. It is important to account for these effects on the EEG to avoid inaccurate interpretation that may affect prognostication.

  4. Removing ballistocardiogram (BCG) artifact from full-scalp EEG acquired inside the MR scanner with Orthogonal Matching Pursuit (OMP)

    PubMed Central

    Xia, Hongjing; Ruan, Dan; Cohen, Mark S.

    2014-01-01

    Ballistocardiogram (BCG) artifact remains a major challenge that renders electroencephalographic (EEG) signals hard to interpret in simultaneous EEG and functional MRI (fMRI) data acquisition. Here, we propose an integrated learning and inference approach that takes advantage of a commercial high-density EEG cap, to estimate the BCG contribution in noisy EEG recordings from inside the MR scanner. To estimate reliably the full-scalp BCG artifacts, a near-optimal subset (20 out of 256) of channels first was identified using a modified recording setup. In subsequent recordings inside the MR scanner, BCG-only signal from this subset of channels was used to generate continuous estimates of the full-scalp BCG artifacts via inference, from which the intended EEG signal was recovered. The reconstruction of the EEG was performed with both a direct subtraction and an optimization scheme. We evaluated the performance on both synthetic and real contaminated recordings, and compared it to the benchmark Optimal Basis Set (OBS) method. In the challenging non-event-related-potential (non-ERP) EEG studies, our reconstruction can yield more than fourteen-fold improvement in reducing the normalized RMS error of EEG signals, compared to OBS. PMID:25120421

  5. Praxis-induced seizures in a patient with juvenile myoclonic epilepsy: MEG-EEG coregistration study.

    PubMed

    de León, Sira Carrasco-García; Niso, Guiomar; Canuet, Leonidas; Burriel-Lobo, Laura; Maestú, Fernando; Rodríguez-Magariños, María Gudín

    2016-01-01

    Juvenile myoclonic epilepsy (JME) is one of the most common generalized idiopathic epilepsies of childhood and adolescence. In some patients with JME, mathematical calculus and praxis may induce myoclonic seizures. A reflex myoclonic seizure was recorded by simultaneous magnetoencephalography (MEG) and electroencephalography (EEG) when a generalized spike-wave synchronous pattern at 3 Hz was observed. Source reconstruction localized the epileptogenic area to the right premotor frontal cortex. The present study demonstrates that the origin of epileptiform activity in JME can be localized in brain areas associated with the premotor frontal cortex.

  6. Neural complexity in patients with poststroke depression: A resting EEG study.

    PubMed

    Zhang, Ying; Wang, Chunfang; Sun, Changcheng; Zhang, Xi; Wang, Yongjun; Qi, Hongzhi; He, Feng; Zhao, Xin; Wan, Baikun; Du, Jingang; Ming, Dong

    2015-12-01

    Poststroke depression (PSD) is one of the most common emotional disorders affecting post-stroke patients. However, the neurophysiological mechanism remains elusive. This study was aimed to study the relationship between complexity of neural electrical activity and PSD. Resting state eye-closed electroencephalogram (EEG) signals of 16 electrodes were recorded in 21 ischemic poststroke depression (PSD) patients, 22 ischemic poststroke non-depression (PSND) patients and 15 healthy controls (CONT). Lempel-Ziv Complexity (LZC) was used to evaluate changes in EEG complexity in PSD patients. Statistical analysis was performed to explore difference among different groups and electrodes. Correlation between the severity of depression (HDRS) and EEG complexity was determined with pearson correlation coefficients. Receiver operating characteristic (ROC) and binary logistic regression analysis were conducted to estimate the discriminating ability of LZC for PSD in specificity, sensitivity and accuracy. PSD patients showed lower neural complexity compared with PSND and CONT subjects in the whole brain regions. There was no significant difference among different brain regions, and no interactions between group and electrodes. None of the LZC significantly correlated with overall depression severity or differentiated symptom severity of 7 items in PSD patients, but in stroke patients, significant correlation was found between HDRS and LZC in the whole brain regions, especially in frontal and temporal. LZC parameters used for PSD recognition possessed more than 85% in specificity, sensitivity and accuracy, suggesting the feasibility of LZC to serve as screening indicators for PSD. Increased slow wave rhythms were found in PSD patients and clearly correlation was confirmed between neuronal complexity and spectral power of the four EEG rhythms. Lesion location of stroke patients in the study distributed in different brain regions, and most of the PSD patients were mild or moderate

  7. Incidence and localizing value of vertigo and dizziness in patients with epilepsy: Video-EEG monitoring study.

    PubMed

    Kim, Dong Wook; Sunwoo, Jun-Sang; Lee, Sang Kun

    2016-10-01

    Vertigo and dizziness are common neurological complaints that have long been associated with epilepsy. However, studies of patients with epileptic vertigo or dizziness with concurrent EEG monitoring are scarce. We performed the present study to investigate the incidence and localizing value of vertigo and dizziness in patients with epilepsy who had confirmation of EEG changes via video-EEG monitoring. Data of aura and clinical seizure episodes of 831 consecutive patients who underwent video-EEG monitoring were analyzed retrospectively. Out of 831 patients, 40 patients (4.8%) experienced vertigo or dizziness as aura (mean age, 32.8±11.8years), all of whom had partial seizures. Eight had mesial temporal, 20 had lateral temporal, four had frontal, one had parietal, and seven had occipital lobe onset seizures. An intracranial EEG with cortical stimulation study was performed in seven patients, and the area of stimulation-induced vertigo or dizziness coincided with the ictal onset area in only one patient. Our study showed that vertigo or dizziness is a common aura in patients with epilepsy, and that the temporal lobe is the most frequent ictal onset area in these patients. However, it can be suggested that the symptomatogenic area in patients with epileptic vertigo and dizziness may not coincide with the ictal onset area.

  8. Wake and Sleep EEG in Patients With Huntington Disease: An eLORETA Study and Review of the Literature.

    PubMed

    Piano, Carla; Mazzucchi, Edoardo; Bentivoglio, Anna Rita; Losurdo, Anna; Calandra Buonaura, Giovanna; Imperatori, Claudio; Cortelli, Pietro; Della Marca, Giacomo

    2017-01-01

    The aim of the study was to evaluate the EEG modifications in patients with Huntington disease (HD) compared with controls, by means of the exact LOw REsolution Tomography (eLORETA) software. We evaluated EEG changes during wake, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Moreover, we reviewed the literature concerning EEG modifications in HD. Twenty-three consecutive adult patients affected by HD were enrolled, 14 women and 9 men, mean age was 57.0 ± 12.4 years. Control subjects were healthy volunteers (mean age 58.2 ± 14.6 years). EEG and polygraphic recordings were performed during wake (before sleep) and during sleep. Sources of EEG activities were determined using the eLORETA software. In wake EEG, significant differences between patients and controls were detected in the delta frequency band (threshold T = ±4.606; P < .01) in the Brodmann areas (BAs) 3, 4, and 6 bilaterally. In NREM sleep, HD patients showed increased alpha power (T = ±4.516; P < .01) in BAs 4 and 6 bilaterally; decreased theta power (T = ±4.516; P < .01) in the BAs 23, 29, and 30; and decreased beta power (T = ±4.516; P < .01) in the left BA 30. During REM, HD patients presented decreased theta and alpha power (threshold T = ±4.640; P < .01) in the BAs 23, 29, 30, and 31 bilaterally. In conclusion, EEG data suggest a motor cortex dysfunction during wake and sleep in HD patients, which correlates with the clinical and polysomnographic evidence of increased motor activity during wake and NREM, and nearly absent motor abnormalities in REM.

  9. Numerical magnitude processing in abacus-trained children with superior mathematical ability: an EEG study.

    PubMed

    Huang, Jian; Du, Feng-lei; Yao, Yuan; Wan, Qun; Wang, Xiao-Song; Chen, Fei-Yan

    2015-08-01

    Distance effect has been regarded as the best established marker of basic numerical magnitude processes and is related to individual mathematical abilities. A larger behavioral distance effect is suggested to be concomitant with lower mathematical achievement in children. However, the relationship between distance effect and superior mathematical abilities is unclear. One could get superior mathematical abilities by acquiring the skill of abacus-based mental calculation (AMC), which can be used to solve calculation problems with exceptional speed and high accuracy. In the current study, we explore the relationship between distance effect and superior mathematical abilities by examining whether and how the AMC training modifies numerical magnitude processing. Thus, mathematical competencies were tested in 18 abacus-trained children (who accepted the AMC training) and 18 non-trained children. Electroencephalography (EEG) waveforms were recorded when these children executed numerical comparison tasks in both Arabic digit and dot array forms. We found that: (a) the abacus-trained group had superior mathematical abilities than their peers; (b) distance effects were found both in behavioral results and on EEG waveforms; (c) the distance effect size of the average amplitude on the late negative-going component was different between groups in the digit task, with a larger effect size for abacus-trained children; (d) both the behavioral and EEG distance effects were modulated by the notation. These results revealed that the neural substrates of magnitude processing were modified by AMC training, and suggested that the mechanism of the representation of numerical magnitude for children with superior mathematical abilities was different from their peers. In addition, the results provide evidence for a view of non-abstract numerical representation.

  10. Multivariate genetic determinants of EEG oscillations in schizophrenia and psychotic bipolar disorder from the BSNIP study

    PubMed Central

    Narayanan, B; Soh, P; Calhoun, V D; Ruaño, G; Kocherla, M; Windemuth, A; Clementz, B A; Tamminga, C A; Sweeney, J A; Keshavan, M S; Pearlson, G D

    2015-01-01

    Schizophrenia (SZ) and psychotic bipolar disorder (PBP) are disabling psychiatric illnesses with complex and unclear etiologies. Electroencephalogram (EEG) oscillatory abnormalities in SZ and PBP probands are heritable and expressed in their relatives, but the neurobiology and genetic factors mediating these abnormalities in the psychosis dimension of either disorder are less explored. We examined the polygenic architecture of eyes-open resting state EEG frequency activity (intrinsic frequency) from 64 channels in 105 SZ, 145 PBP probands and 56 healthy controls (HCs) from the multisite BSNIP (Bipolar-Schizophrenia Network on Intermediate Phenotypes) study. One million single-nucleotide polymorphisms (SNPs) were derived from DNA. We assessed eight data-driven EEG frequency activity derived from group-independent component analysis (ICA) in conjunction with a reduced subset of 10 422 SNPs through novel multivariate association using parallel ICA (para-ICA). Genes contributing to the association were examined collectively using pathway analysis tools. Para-ICA extracted five frequency and nine SNP components, of which theta and delta activities were significantly correlated with two different gene components, comprising genes participating extensively in brain development, neurogenesis and synaptogenesis. Delta and theta abnormality was present in both SZ and PBP, while theta differed between the two disorders. Theta abnormalities were also mediated by gene clusters involved in glutamic acid pathways, cadherin and synaptic contact-based cell adhesion processes. Our data suggest plausible multifactorial genetic networks, including novel and several previously identified (DISC1) candidate risk genes, mediating low frequency delta and theta abnormalities in psychoses. The gene clusters were enriched for biological properties affecting neural circuitry and involved in brain function and/or development. PMID:26101851

  11. Panayiotopoulos syndrome and symptomatic occipital lobe epilepsy of childhood: a clinical and EEG study.

    PubMed

    Tata, Gulten; Guveli, Betul Tekin; Dortcan, Nimet; Cokar, Ozlem; Kurucu, Hatice; Demirbilek, Veysi; Dervent, Aysin

    2014-06-01

    Panayiotopoulos syndrome (PS) is an age-related seizure susceptibility syndrome that affects the central autonomic system. Although the majority of the few ictal recordings obtained so far suggest an occipital origin, semiological and interictal EEG data appear to favour more extensive involvement. In this study, the characteristics (including those based on semiology and EEG) of children with Panayiotopoulos syndrome (n=24) and those with lesion-related, symptomatic occipital lobe epilepsy (SOLE) (n=23) were compared. Detailed semiological information and EEG parameters including the localisation, distribution, density (n/sec), reactivity, and morphological characteristics of spike-wave foci and their relationship with different states of vigilance were compared between the two groups. The age at seizure onset was significantly younger in patients with symptomatic occipital lobe epilepsy than in those with PS (mean age at onset: 3.4 versus 5.6 years, respectively; p=0.044). Autonomic seizures (p=0.001) and ictal syncope (p=0.055) were more frequent in PS than in symptomatic occipital lobe epilepsy (87.5% and 37.5% versus 43.5% and 13%, respectively). The interictal spike-wave activity increased significantly during non-rapid eye movement (non-REM) sleep in both groups. The spike waves in non-REM seen in PS tended to spread mainly to central and centro-temporal regions. The results indicate that although common features do exist, Panayiotopoulos syndrome differs from symptomatic occipital lobe epilepsy and has a unique low epileptogenic threshold related to particular brain circuits.

  12. Multivariate genetic determinants of EEG oscillations in schizophrenia and psychotic bipolar disorder from the BSNIP study.

    PubMed

    Narayanan, B; Soh, P; Calhoun, V D; Ruaño, G; Kocherla, M; Windemuth, A; Clementz, B A; Tamminga, C A; Sweeney, J A; Keshavan, M S; Pearlson, G D

    2015-06-23

    Schizophrenia (SZ) and psychotic bipolar disorder (PBP) are disabling psychiatric illnesses with complex and unclear etiologies. Electroencephalogram (EEG) oscillatory abnormalities in SZ and PBP probands are heritable and expressed in their relatives, but the neurobiology and genetic factors mediating these abnormalities in the psychosis dimension of either disorder are less explored. We examined the polygenic architecture of eyes-open resting state EEG frequency activity (intrinsic frequency) from 64 channels in 105 SZ, 145 PBP probands and 56 healthy controls (HCs) from the multisite BSNIP (Bipolar-Schizophrenia Network on Intermediate Phenotypes) study. One million single-nucleotide polymorphisms (SNPs) were derived from DNA. We assessed eight data-driven EEG frequency activity derived from group-independent component analysis (ICA) in conjunction with a reduced subset of 10,422 SNPs through novel multivariate association using parallel ICA (para-ICA). Genes contributing to the association were examined collectively using pathway analysis tools. Para-ICA extracted five frequency and nine SNP components, of which theta and delta activities were significantly correlated with two different gene components, comprising genes participating extensively in brain development, neurogenesis and synaptogenesis. Delta and theta abnormality was present in both SZ and PBP, while theta differed between the two disorders. Theta abnormalities were also mediated by gene clusters involved in glutamic acid pathways, cadherin and synaptic contact-based cell adhesion processes. Our data suggest plausible multifactorial genetic networks, including novel and several previously identified (DISC1) candidate risk genes, mediating low frequency delta and theta abnormalities in psychoses. The gene clusters were enriched for biological properties affecting neural circuitry and involved in brain function and/or development.

  13. Declining functional connectivity and changing hub locations in Alzheimer's disease: an EEG study.

    PubMed

    Engels, Marjolein M A; Stam, Cornelis J; van der Flier, Wiesje M; Scheltens, Philip; de Waal, Hanneke; van Straaten, Elisabeth C W

    2015-08-20

    EEG studies have shown that patients with Alzheimer's disease (AD) have weaker functional connectivity than controls, especially in higher frequency bands. Furthermore, active regions seem more prone to AD pathology. How functional connectivity is affected in AD subgroups of disease severity and how network hubs (highly connected brain areas) change is not known. We compared AD patients with different disease severity and controls in terms of functional connections, hub strength and hub location. We studied routine 21-channel resting-state electroencephalography (EEG) of 318 AD patients (divided into tertiles based on disease severity: mild, moderate and severe AD) and 133 age-matched controls. Functional connectivity between EEG channels was estimated with the Phase Lag Index (PLI). From the PLI-based connectivity matrix, the minimum spanning tree (MST) was derived. For each node (EEG channel) in the MST, the betweenness centrality (BC) was computed, a measure to quantify the relative importance of a node within the network. Then we derived color-coded head plots based on BC values and calculated the center of mass (the exact middle had x and y values of 0). A shifting of the hub locations was defined as a shift of the center of mass on the y-axis across groups. Multivariate general linear models with PLI or BC values as dependent variables and the groups as continuous variables were used in the five conventional frequency bands. We found that functional connectivity decreases with increasing disease severity in the alpha band. All, except for posterior, regions showed increasing BC values with increasing disease severity. The center of mass shifted from posterior to more anterior regions with increasing disease severity in the higher frequency bands, indicating a loss of relative functional importance of the posterior brain regions. In conclusion, we observed decreasing functional connectivity in the posterior regions, together with a shifted hub location from

  14. Study of the frequency parameters of EEG influenced by zone-dependent local ELF-MF exposure on the human head.

    PubMed

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

    2012-06-01

    It has been reported that human subjects exposed to electromagnetic fields exhibit changes in human EEG signals at the frequency of stimulation. The aim of the present study was to expose different parts of the brain to extremely low-frequency magnetic fields locally and investigate EEG power spectrum alters at the frequency of stimulation. EEG relative power spectrum were evaluated at 3, 5, 10, 17, and 45 Hz frequencies at T4, T3, F3, Cz, and F4 points, respectively, when these points were exposed to magnetic fields with similar frequencies and 100 μT intensity. The paired t-test results showed that power value of EEG did not alter significantly at the frequency of stimulation (P<0.05). Further, significant changes in different EEG bands caused by locally exposing to ELF-MF in different points of brain were observed. The changes in the EEG bands were not limited necessarily to the exposure point.

  15. 'Is Going through Clinical Test a Headache?' An HRV Study and Descriptive Report of Subjective Experience of Undergoing EEG Testing.

    PubMed

    Kathrotia, Rajesh; Singh, Yogesh; Goel, Arun; Patil, Prashant

    2016-03-01

    To explore the heart rate variability (HRV) changes and subjective perception of undergoing electroencephalography (EEG). We conducted a study on 35 healthy male volunteers. The intervention consisted of placing 23 disc-type EEG electrodes of 5-7 mm diameter with long flexible lead according to international 10-20 system for the duration of 30 min, in a sitting position, on the scalp. The outcome measures were time and frequency domain parameters of HRV analysis and descriptive report of subjective experiences on a 3-point Likert scale. The perception of undergoing EEG ranged from pleasant to uneasy. For 13 (37%) participants it was soothing and relaxing, for 11 (31.5%) it was neutral and for the rest 11 (31.5%) it was uneasy and restrictive in nature. However, HRV analysis of the pre and post EEG, showed no statistically significant difference. In our study, the mixed subjective experience of undergoing EEG may be due to individual variation in the perception of the intervention. No difference in HRV parameters may be because of 2 possibilities. The first possibility is varied experiences of procedure with temporal progression. Same participants may have experienced 2 opposite extremes of experiences over and over again, which may have cancelled out sympathetic and parasympathetic responses. The second possibility may be that no stress is generated during clinical test.

  16. On the effect of resistive EEG electrodes and leads during 7 T MRI: simulation and temperature measurement studies.

    PubMed

    Angelone, Leonardo M; Vasios, Christos E; Wiggins, Graham; Purdon, Patrick L; Bonmassar, Giorgio

    2006-07-01

    The purpose of the study was to assess the effects of electrodes and leads on electromagnetic field and specific absorption rate (SAR) distributions during simultaneous electroencephalography (EEG) and 7-T MRI. Two different approaches were evaluated and compared to the case without electrodes: (a) the use of different EEG lead resistivity and (b) the use of a radiofrequency (RF) resistor on the lead near the EEG electrode. These configurations are commonly used in research and clinical settings. Electromagnetic field and SAR distributions generated by the transmit RF coil were evaluated using finite difference time domain simulations on an anatomically accurate head model. The spatiotemporal changes of temperature were estimated with the heat equation. Temperature changes during turbo spin echo sequences were also measured using a custom-made phantom: the conductive head mannequin anthropomorphic (CHEMA). The results of this study showed that the SAR and temperature distributions in CHEMA (a) increased when using low resistive leads, with respect to the no-electrode case; (b) were affected by the resistivity of the EEG leads, with carbon fiber leads performing better than standard copper leads; and (c) were not affected by the use of an RF resistor between the EEG electrode and the lead.

  17. Evidence of CNS impairment in HIV infection: clinical, neuropsychological, EEG, and MRI/MRS study

    PubMed Central

    Harrison, M; Newman, S; Hall-Craggs, M; Fowler, C; Miller, R; Kendall, B; Paley, M; Wilkinson, I; Sweeney, B; Lunn, S; Carter, S; Williams, I

    1998-01-01

    OBJECTIVES—To identify by clinical examination, EEG, MRI, and proton spectroscopy, and neuropsychological assessment the prevalence of signs of CNS involvement in patients infected with HIV, and to relate such findings to the evidence of immunosuppression.
METHODS—The design was a cross sectional analysis of a cohort of male patients with infected HIV with an AIDS defining diagnosis or low CD4 count (<350), and seropositive asymptomatic subjects, both groups being followed up in a longitudinal study. Control groups consisted of seronegative subjects from the same genitourinary medicine clinics.
RESULTS—This report sets out the cross sectional findings at the seventh visit in the longitudinal study. Patients with AIDS had more signs of neurological dysfunction, poorer performance on a neuropsychological test battery, were more likely to have an abnormal EEG, and to have abnormalities on MRI. They more often had cerebral atrophy, abnormal appearing white matter, , and abnormal relaxometry and spectroscopy. There was little evidence of abnormality in seropositive people who had a CD4 count >350 compared with seronegative people from a similar background.
CONCLUSIONS—Detailed testing failed to disclose significant CNS impairment without immunosuppression in men infected with HIV. Findings from MRI and magnetic resonance spectroscopy (MRS) correlated with those of the neurological examination and neuropsychogical assessment. A combination of such assessments offers a simple surrogate for studies of CNS involvement in HIV disease.

 PMID:9728940

  18. Electroencephalography (EEG) for neurological prognostication after cardiac arrest and targeted temperature management; rationale and study design.

    PubMed

    Westhall, Erik; Rosén, Ingmar; Rossetti, Andrea O; van Rootselaar, Anne-Fleur; Kjaer, Troels Wesenberg; Horn, Janneke; Ullén, Susann; Friberg, Hans; Nielsen, Niklas; Cronberg, Tobias

    2014-08-16

    Electroencephalography (EEG) is widely used to assess neurological prognosis in patients who are comatose after cardiac arrest, but its value is limited by varying definitions of pathological patterns and by inter-rater variability. The American Clinical Neurophysiology Society (ACNS) has recently proposed a standardized EEG-terminology for critical care to address these limitations. In the TTM-trial, 399 post cardiac arrest patients who remained comatose after rewarming underwent a routine EEG. The presence of clinical seizures, use of sedatives and antiepileptic drugs during the EEG-registration were prospectively documented. A well-defined terminology for interpreting post cardiac arrest EEGs is critical for the use of EEG as a prognostic tool. The TTM-trial is registered at ClinicalTrials.gov (NCT01020916).

  19. Bright light as a sleepiness prophylactic: a laboratory study of subjective ratings and EEG.

    PubMed

    Akerstedt, Torbjörn; Landström, Ulf; Byström, Marianne; Nordström, Bertil; Wibom, Roger

    2003-12-01

    Sleepiness is a major problem when driving a vehicle and contributes to 15 to 30% of all road accidents. One possible countermeasure may be exposure to light. This study was designed to test whether 30 min. of exposure to a bright light would reduce subjective sleepiness and EEG indicators of sleepiness, such as alpha and theta power density. 10 female and 10 male university students (recruited through advertisements) participated in a laboratory study, consisting of 30 min. of dim light followed by 30 min. of bright light (or red light in the control condition) exposures and then by 30 min. of dim light exposure. In the dim light exposure, the luminance was 20 cd/m2, and the illuminance was about 5 Lux. In the bright exposure, the luminance was 500 cd/m2 and the illuminance about 2000 Lux. In the red light exposure, the luminance was 10 cd/m2 and the illuminance about 30 Lux. The subject sat in a chair with a seating comfort corresponding to that of a driver's seat. Analysis showed that the subjects became subjectively sleepier during the pre-exposure condition, and alpha and theta power density increased in their EEGs. The intervention significantly reduced subjective sleepiness but did not have significant effects on alpha or theta power density. The results suggest that a short (30 min.) exposure to bright light may not be a useful prophylactic against sleepiness for the period following the exposure.

  20. EEG-fMRI Methods for the Study of Brain Networks during Sleep

    PubMed Central

    Duyn, Jeff H.

    2012-01-01

    Modern neuroimaging methods may provide unique insights into the mechanism and role of sleep, as well as into particular mechanisms of brain function in general. Many of the recent neuroimaging studies have used concurrent EEG and fMRI, which present unique technical challenges ranging from the difficulty of inducing sleep in the MRI environment to appropriate instrumentation and data processing methods to obtain artifact free data. In addition, the use of EEG-fMRI during sleep leads to unique data interpretation issues, as common approaches developed for the analysis of task-evoked activity do not apply to sleep. Reviewed are a variety of statistical approaches that can be used to characterize brain activity from fMRI data acquired during sleep, with an emphasis on approaches that investigate the presence of correlated activity between brain regions. Each of these approaches has advantages and disadvantages that must be considered in concert with the theoretical questions of interest. Specifically, fundamental theories of sleep control and function should be considered when designing these studies and when choosing the associated statistical approaches. For example, the notion that local brain activity during sleep may be triggered by local, use-dependent activity during wakefulness may be tested by analyzing sleep networks as statistically independent components. Alternatively, the involvement of regions in more global processes such as arousal may be investigated with correlation analysis. PMID:22783221

  1. Study on Brain Dynamics by Non Linear Analysis of Music Induced EEG Signals

    NASA Astrophysics Data System (ADS)

    Banerjee, Archi; Sanyal, Shankha; Patranabis, Anirban; Banerjee, Kaushik; Guhathakurta, Tarit; Sengupta, Ranjan; Ghosh, Dipak; Ghose, Partha

    2016-02-01

    Music has been proven to be a valuable tool for the understanding of human cognition, human emotion, and their underlying brain mechanisms. The objective of this study is to analyze the effect of Hindustani music on brain activity during normal relaxing conditions using electroencephalography (EEG). Ten male healthy subjects without special musical education participated in the study. EEG signals were acquired at the frontal (F3/F4) lobes of the brain while listening to music at three experimental conditions (rest, with music and without music). Frequency analysis was done for the alpha, theta and gamma brain rhythms. The finding shows that arousal based activities were enhanced while listening to Hindustani music of contrasting emotions (romantic/sorrow) for all the subjects in case of alpha frequency bands while no significant changes were observed in gamma and theta frequency ranges. It has been observed that when the music stimulus is removed, arousal activities as evident from alpha brain rhythms remain for some time, showing residual arousal. This is analogous to the conventional 'Hysteresis' loop where the system retains some 'memory' of the former state. This is corroborated in the non linear analysis (Detrended Fluctuation Analysis) of the alpha rhythms as manifested in values of fractal dimension. After an input of music conveying contrast emotions, withdrawal of music shows more retention as evidenced by the values of fractal dimension.

  2. Mapping brain injury with symmetrical-channels' EEG signal analysis--a pilot study.

    PubMed

    Li, Yi; Liu, Xiao-ping; Ling, Xian-hong; Li, Jing-qi; Yang, Wen-wei; Zhang, Dan-ke; Li, Li-hua; Yang, Yong

    2014-05-21

    A technique for detecting brain injury at the bedside has great clinical value, but conventional imaging techniques (such as computed tomography [CT] and magnetic resonance imaging) are impractical. In this study, a novel method-the symmetrical channel electroencephalogram (EEG) signal analysis-was developed for this purpose. The study population consisted of 45 traumatic brain injury patients and 10 healthy controls. EEG signals in resting and stimulus states were acquired, and approximate entropy (ApEn) and slow-wave coefficient were extracted to calculate the ratio values of ApEn and SWC for injured and uninjured areas. Statistical analyses showed that the ratio values for both ApEn and SWC between injured and uninjured brain areas differed significantly (P<0.05) for both resting and name call stimulus states. A set of criteria (range of ratio values) to determine whether a brain area is injured or uninjured was proposed and its reliability was verified by statistical analyses and CT images.

  3. Phase to amplitude coupling as a potential biomarker for creative ideation: an EEG study.

    PubMed

    Marmpena, Mina; Dimitriadis, Stavros I; Thakor, Nitish; Bezerianos, Anastasios

    2016-08-01

    The most consistent finding of creative ideation in the neuroscientific study of creativity is the increment of EEG α power. However, the majority of existing studies focused only on ERP experimental paradigms while only a few analyzed time-related changes of EEG α power patterns during the time unlocked creation of ideas. Here, we designed an experimental paradigm where the participants were asked to generate alternative uses of everyday objects (AU task). For the control task, we adopted an Object Characteristics (OC) task, for which participants were asked to list typical characteristics or properties of an object. We estimated relative power spectrum, global efficiency from brain networks constructed with the imaginary part of coherence and phase-to-amplitude coupling (PAC) as potential biomarkers of creativity. Both relative power spectrum and nodal global efficiency failed to reach significant level by comparing AU with OC. In contrast, statistically significant differences between AU and OC were detected with PAC estimated within sensors in frequency pairs θ-γ and α2-γ. Our results can be the ground for both detecting and designing a connectomic biomarker of creativity.

  4. Video-EEG study of psychogenic nonepileptic seizures: differential characteristics in patients with and without epilepsy.

    PubMed

    Mari, Francesco; Di Bonaventura, Carlo; Vanacore, Nicola; Fattouch, Jinane; Vaudano, Anna Elisabetta; Egeo, Gabriella; Berardelli, Alfredo; Manfredi, Mario; Prencipe, Massimiliano; Giallonardo, Anna Teresa

    2006-01-01

    Psychogenic nonepileptic seizures (PNES) are episodes that may resemble epileptic seizures (ES) but are not associated with abnormal electrical discharges in the brain. Video-EEG recording of a typical episode is considered the best diagnostic tool available. PNES are, however, also documented in patients with epilepsy (PNES/ES). The purpose of this study was to assess this comorbid population, focusing on the differences between patients with PNES/ES and patients with PNES alone. We reviewed 110 PNES episodes, occurring spontaneously or induced by means of suggestion techniques, recorded in our video-EEG laboratory over a period of eight years. We identified two subgroups of patients, consisting of 85 PNES cases and 25 PNES/ES cases, and assessed any differences in their characteristics by reviewing a number of variables (age, sex, clinical features, antiepileptic therapy, age of onset, time to diagnosis, pathological history, and length of follow-up). The comparison between the two subgroups revealed that PNES/ES patients displayed some statistically significant differences when compared with PNES alone patients, i.e., younger age, a higher percentage of spontaneously activated events, a shorter disease duration, a longer time to PNES diagnosis, and a lower percentage lost at follow-up. This study confirms that PNES is a common, though probably underestimated, occurrence in epilepsy services. Our results shed light on some different characteristics between PNES and PNES/ES patients.

  5. Combining Different Tools for EEG Analysis to Study the Distributed Character of Language Processing

    PubMed Central

    da Rocha, Armando Freitas; Foz, Flávia Benevides; Pereira, Alfredo

    2015-01-01

    Recent studies on language processing indicate that language cognition is better understood if assumed to be supported by a distributed intelligent processing system enrolling neurons located all over the cortex, in contrast to reductionism that proposes to localize cognitive functions to specific cortical structures. Here, brain activity was recorded using electroencephalogram while volunteers were listening or reading small texts and had to select pictures that translate meaning of these texts. Several techniques for EEG analysis were used to show this distributed character of neuronal enrollment associated with the comprehension of oral and written descriptive texts. Low Resolution Tomography identified the many different sets (si) of neurons activated in several distinct cortical areas by text understanding. Linear correlation was used to calculate the information H(ei) provided by each electrode of the 10/20 system about the identified si. H(ei) Principal Component Analysis (PCA) was used to study the temporal and spatial activation of these sources si. This analysis evidenced 4 different patterns of H(ei) covariation that are generated by neurons located at different cortical locations. These results clearly show that the distributed character of language processing is clearly evidenced by combining available EEG technologies. PMID:26713089

  6. EEG-fMRI Methods for the Study of Brain Networks during Sleep.

    PubMed

    Duyn, Jeff H

    2012-01-01

    Modern neuroimaging methods may provide unique insights into the mechanism and role of sleep, as well as into particular mechanisms of brain function in general. Many of the recent neuroimaging studies have used concurrent EEG and fMRI, which present unique technical challenges ranging from the difficulty of inducing sleep in the MRI environment to appropriate instrumentation and data processing methods to obtain artifact free data. In addition, the use of EEG-fMRI during sleep leads to unique data interpretation issues, as common approaches developed for the analysis of task-evoked activity do not apply to sleep. Reviewed are a variety of statistical approaches that can be used to characterize brain activity from fMRI data acquired during sleep, with an emphasis on approaches that investigate the presence of correlated activity between brain regions. Each of these approaches has advantages and disadvantages that must be considered in concert with the theoretical questions of interest. Specifically, fundamental theories of sleep control and function should be considered when designing these studies and when choosing the associated statistical approaches. For example, the notion that local brain activity during sleep may be triggered by local, use-dependent activity during wakefulness may be tested by analyzing sleep networks as statistically independent components. Alternatively, the involvement of regions in more global processes such as arousal may be investigated with correlation analysis.

  7. Dynamic Causal Modelling of epileptic seizure propagation pathways: a combined EEG-fMRI study.

    PubMed

    Murta, Teresa; Leal, Alberto; Garrido, Marta I; Figueiredo, Patrícia

    2012-09-01

    Simultaneous EEG-fMRI offers the possibility of non-invasively studying the spatiotemporal dynamics of epileptic activity propagation from the focus towards an extended brain network, through the identification of the haemodynamic correlates of ictal electrical discharges. In epilepsy associated with hypothalamic hamartomas (HH), seizures are known to originate in the HH but different propagation pathways have been proposed. Here, Dynamic Causal Modelling (DCM) was employed to estimate the seizure propagation pathway from fMRI data recorded in a HH patient, by testing a set of clinically plausible network connectivity models of discharge propagation. The model consistent with early propagation from the HH to the temporal-occipital lobe followed by the frontal lobe was selected as the most likely model to explain the data. Our results demonstrate the applicability of DCM to investigate patient-specific effective connectivity in epileptic networks identified with EEG-fMRI. In this way, it is possible to study the propagation pathway of seizure activity, which has potentially great impact in the decision of the surgical approach for epilepsy treatment.

  8. The Dynamics of Visual Experience, an EEG Study of Subjective Pattern Formation

    PubMed Central

    Elliott, Mark A.; Twomey, Deirdre; Glennon, Mark

    2012-01-01

    Background Since the origin of psychological science a number of studies have reported visual pattern formation in the absence of either physiological stimulation or direct visual-spatial references. Subjective patterns range from simple phosphenes to complex patterns but are highly specific and reported reliably across studies. Methodology/Principal Findings Using independent-component analysis (ICA) we report a reduction in amplitude variance consistent with subjective-pattern formation in ventral posterior areas of the electroencephalogram (EEG). The EEG exhibits significantly increased power at delta/theta and gamma-frequencies (point and circle patterns) or a series of high-frequency harmonics of a delta oscillation (spiral patterns). Conclusions/Significance Subjective-pattern formation may be described in a way entirely consistent with identical pattern formation in fluids or granular flows. In this manner, we propose subjective-pattern structure to be represented within a spatio-temporal lattice of harmonic oscillations which bind topographically organized visual-neuronal assemblies by virtue of low frequency modulation. PMID:22292053

  9. A pilot study of continuous limited-channel aEEG in term infants with encephalopathy.

    PubMed

    Lawrence, Russell; Mathur, Amit; Nguyen The Tich, Sylvie; Zempel, John; Inder, Terrie

    2009-06-01

    To evaluate the accuracy, feasibility, and impact of limited-channel amplitude integrated electroencephalogram (aEEG) monitoring in encephalopathic infants. Encephalopathic infants were placed on limited-channel aEEG with a software-based seizure event detector for 72 hours. A 12-hour epoch of conventional EEG-video (cEEG) was simultaneously collected. Infants were randomly assigned to monitoring that was blinded or visible to the clinical team. If a seizure detection event occurred in the visible group, the clinical team interpreted whether the event was a seizure, based on review of the limited-channel aEEG. EEG data were reviewed independently offline. In more than 68 hours per infant of limited-channel aEEG monitoring, 1116 seizures occurred (>90% clinically silent), with 615 detected by the seizure event detector (55%). Detection improved with increasing duration of seizures (73% >30 seconds, 87% >60 seconds). Bedside physicians were able to accurately use this algorithm to differentiate true seizures from false-positives. The visible group had a 52% reduction in seizure burden (P = .114) compared with the blinded group. Monitoring for seizures with limited-channel aEEG can be accurately interpreted, compares favorably with cEEG, and is associated with a trend toward reduced seizure burden.

  10. Respiratory-cycle related analysis of the EEG-spectrum during sleep: a healthy population study.

    PubMed

    Garcia-Molina, Gary; Bialas, Piotr

    2013-01-01

    Recent research has shown the EEG's spectral changes that occur in synchrony with the respiratory-cycle. During wakefulness, and for healthy subjects it is reported that the EEG power in several frequency bands changes between the expiratory and inspiratory phases. For sleep-disordered breathing (SDB) patients, it is reported that the amplitude of changes in normalized EEG power (referred to as respiratory-cycle related EEG changes RCREC) within a respiratory-cycle decreases after a successful intervention to alleviate the SDB condition. In this paper, we focus on analyzing the changes in the sleep’s EEG spectrum related to the respiratory-cycle for a healthy population comprising 39 subjects. For 3 sleep stages (N2, N3, REM), 6 EEG channels, and 7 frequency bands, two types of EEG spectral analyzes were considered: 1) the ratio between the EEG power during expiration and that during inspiration, and 2) the RCREC. For the first type of analysis and at the population level, no statistically significant difference was found between the EEG power during expiration and that during inspiration. For the second type of analysis, the RCREC for all conditions is at a level that is statistically significantly larger than 0.1. The latter being the value at which the RCREC decreased after successful SDB intervention.

  11. High Density Digital Data Storage System

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth D., II; Gray, David L.; Rowland, Wayne D.

    1991-01-01

    The High Density Digital Data Storage System was designed to provide a cost effective means for storing real-time data from the field-deployable digital acoustic measurement system. However, the high density data storage system is a standalone system that could provide a storage solution for many other real time data acquisition applications. The storage system has inputs for up to 20 channels of 16-bit digital data. The high density tape recorders presently being used in the storage system are capable of storing over 5 gigabytes of data at overall transfer rates of 500 kilobytes per second. However, through the use of data compression techniques the system storage capacity and transfer rate can be doubled. Two tape recorders have been incorporated into the storage system to produce a backup tape of data in real-time. An analog output is provided for each data channel as a means of monitoring the data as it is being recorded.

  12. The dynamics of contour integration: A simultaneous EEG-fMRI study.

    PubMed

    Mijović, Bogdan; De Vos, Maarten; Vanderperren, Katrien; Machilsen, Bart; Sunaert, Stefan; Van Huffel, Sabine; Wagemans, Johan

    2014-03-01

    To study the dynamics of contour integration in the human brain, we simultaneously acquired EEG and fMRI data while participants were engaged in a passive viewing task. The stimuli were Gabor arrays with some Gabor elements positioned on the contour of an embedded shape, in three conditions: with local and global structure (perfect contour alignment), with global structure only (orthogonal orientations interrupting the alignment), or without contour. By applying JointICA to the EEG and fMRI responses of the subjects, new insights could be obtained that cannot be derived from unimodal recordings. In particular, only in the global structure condition, an ERP peak around 300ms was identified that involved a loop from LOC to the early visual areas. This component can be interpreted as being related to the verification of the consistency of the different local elements with the globally defined shape, which is necessary when perfect local-to-global alignment is absent. By modifying JointICA, a quantitative comparison of brain regions and the time-course of their interplay were obtained between different conditions. More generally, we provide additional support for the presence of feedback loops from higher areas to lower level sensory regions.

  13. Preliminary study of Alzheimer's Disease diagnosis based on brain electrical signals using wireless EEG

    NASA Astrophysics Data System (ADS)

    Handayani, N.; Akbar, Y.; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, W. P.

    2016-03-01

    This research aims to study brain's electrical signals recorded using EEG as a basis for the diagnosis of patients with Alzheimer's Disease (AD). The subjects consisted of patients with AD, and normal subjects are used as the control. Brain signals are recorded for 3 minutes in a relaxed condition and with eyes closed. The data is processed using power spectral analysis, brain mapping and chaos test to observe the level of complexity of EEG's data. The results show a shift in the power spectral in the low frequency band (delta and theta) in AD patients. The increase of delta and theta occurs in lobus frontal area and lobus parietal respectively. However, there is a decrease of alpha activity in AD patients where in the case of normal subjects with relaxed condition, brain alpha wave dominates the posterior area. This is confirmed by the results of brain mapping. While the results of chaos analysis show that the average value of MMLE is lower in AD patients than in normal subjects. The level of chaos associated with neural complexity in AD patients with lower neural complexity is due to neuronal damage caused by the beta amyloid plaques and tau protein in neurons.

  14. Mapping perception to action in piano practice: a longitudinal DC-EEG study

    PubMed Central

    Bangert, Marc; Altenmüller, Eckart O

    2003-01-01

    Background Performing music requires fast auditory and motor processing. Regarding professional musicians, recent brain imaging studies have demonstrated that auditory stimulation produces a co-activation of motor areas, whereas silent tapping of musical phrases evokes a co-activation in auditory regions. Whether this is obtained via a specific cerebral relay station is unclear. Furthermore, the time course of plasticity has not yet been addressed. Results Changes in cortical activation patterns (DC-EEG potentials) induced by short (20 minute) and long term (5 week) piano learning were investigated during auditory and motoric tasks. Two beginner groups were trained. The 'map' group was allowed to learn the standard piano key-to-pitch map. For the 'no-map' group, random assignment of keys to tones prevented such a map. Auditory-sensorimotor EEG co-activity occurred within only 20 minutes. The effect was enhanced after 5-week training, contributing elements of both perception and action to the mental representation of the instrument. The 'map' group demonstrated significant additional activity of right anterior regions. Conclusion We conclude that musical training triggers instant plasticity in the cortex, and that right-hemispheric anterior areas provide an audio-motor interface for the mental representation of the keyboard. PMID:14575529

  15. Spatial patterning of the neonatal EEG suggests a need for a high number of electrodes.

    PubMed

    Odabaee, Maryam; Freeman, Walter J; Colditz, Paul B; Ramon, Ceon; Vanhatalo, Sampsa

    2013-03-01

    There is an increasing demand for source analysis of neonatal EEG, but currently there is inadequate knowledge about i) the spatial patterning of neonatal scalp EEG and hence ii) the number of electrodes needed to capture neonatal EEG in full spatial detail. This study addresses these issues by using a very high density (2.5mm interelectrode spacing) linear electrode array to assess the spatial power spectrum, by using a high density (64 electrodes) EEG cap to assess the spatial extent of the common oscillatory bouts in the neonatal EEG and by using a neonatal size spherical head model to assess the effects of source depth and skull conductivities on the spatial frequency spectrum. The linear array recordings show that the spatial power spectrum decays rapidly until about 0.5-0.8 cycles per centimeter. The dense array EEG recordings show that the amplitude of oscillatory events decays within 4-6 cm to the level of global background activity, and that the higher frequencies (12-20 Hz) show the most rapid spatial decline in amplitude. Simulation with spherical head model showed that realistic variation in skull conductivity and source depths can both introduce orders of magnitude difference in the spatial frequency of the scalp EEG. Calculation of spatial Nyquist frequencies from the spatial power spectra suggests that an interelectrode distance of about 6-10mm would suffice to capture the full spatial texture of the raw EEG signal at the neonatal scalp without spatial aliasing or under-sampling. The spatial decay of oscillatory events suggests that a full representation of their spatial characteristics requires an interelectrode distance of 10-20mm. The findings show that the conventional way of recording neonatal EEG with about 10 electrodes ignores most spatial EEG content, that increasing the electrode density is necessary to improve neonatal EEG source localization and information extraction, and that prospective source models will need to carefully consider the

  16. Does EEG-Neurofeedback Improve Neurocognitive Functioning in Children with Attention-Deficit/Hyperactivity Disorder? A Systematic Review and a Double-Blind Placebo-Controlled Study

    ERIC Educational Resources Information Center

    Vollebregt, Madelon A.; van Dongen-Boomsma, Martine; Buitelaar, Jan K.; Slaats-Willemse, Dorine

    2014-01-01

    Background: The number of placebo-controlled randomized studies relating to EEG-neurofeedback and its effect on neurocognition in attention-deficient/hyperactivity disorder (ADHD) is limited. For this reason, a double blind, randomized, placebo-controlled study was designed to assess the effects of EEG-neurofeedback on neurocognitive functioning…

  17. Does EEG-Neurofeedback Improve Neurocognitive Functioning in Children with Attention-Deficit/Hyperactivity Disorder? A Systematic Review and a Double-Blind Placebo-Controlled Study

    ERIC Educational Resources Information Center

    Vollebregt, Madelon A.; van Dongen-Boomsma, Martine; Buitelaar, Jan K.; Slaats-Willemse, Dorine

    2014-01-01

    Background: The number of placebo-controlled randomized studies relating to EEG-neurofeedback and its effect on neurocognition in attention-deficient/hyperactivity disorder (ADHD) is limited. For this reason, a double blind, randomized, placebo-controlled study was designed to assess the effects of EEG-neurofeedback on neurocognitive functioning…

  18. ICA-Derived EEG Correlates to Mental Fatigue, Effort, and Workload in a Realistically Simulated Air Traffic Control Task.

    PubMed

    Dasari, Deepika; Shou, Guofa; Ding, Lei

    2017-01-01

    Electroencephalograph (EEG) has been increasingly studied to identify distinct mental factors when persons perform cognitively demanding tasks. However, most of these studies examined EEG correlates at channel domain, which suffers the limitation that EEG signals are the mixture of multiple underlying neuronal sources due to the volume conduction effect. Moreover, few studies have been conducted in real-world tasks. To precisely probe EEG correlates with specific neural substrates to mental factors in real-world tasks, the present study examined EEG correlates to three mental factors, i.e., mental fatigue [also known as time-on-task (TOT) effect], workload and effort, in EEG component signals, which were obtained using an independent component analysis (ICA) on high-density EEG data. EEG data were recorded when subjects performed a realistically simulated air traffic control (ATC) task for 2 h. Five EEG independent component (IC) signals that were associated with specific neural substrates (i.e., the frontal, central medial, motor, parietal, occipital areas) were identified. Their spectral powers at their corresponding dominant bands, i.e., the theta power of the frontal IC and the alpha power of the other four ICs, were detected to be correlated to mental workload and effort levels, measured by behavioral metrics. Meanwhile, a linear regression analysis indicated that spectral powers at five ICs significantly increased with TOT. These findings indicated that different levels of mental factors can be sensitively reflected in EEG signals associated with various brain functions, including visual perception, cognitive processing, and motor outputs, in real-world tasks. These results can potentially aid in the development of efficient operational interfaces to ensure productivity and safety in ATC and beyond.

  19. Functional and effective brain connectivity for discrimination between Alzheimer's patients and healthy individuals: A study on resting state EEG rhythms.

    PubMed

    Blinowska, Katarzyna J; Rakowski, Franciszek; Kaminski, Maciej; De Vico Fallani, Fabrizio; Del Percio, Claudio; Lizio, Roberta; Babiloni, Claudio

    2017-04-01

    This exploratory study provided a proof of concept of a new procedure using multivariate electroencephalographic (EEG) topographic markers of cortical connectivity to discriminate normal elderly (Nold) and Alzheimer's disease (AD) individuals. The new procedure was tested on an existing database formed by resting state eyes-closed EEG data (19 exploring electrodes of 10-20 system referenced to linked-ear reference electrodes) recorded in 42 AD patients with dementia (age: 65.9years±8.5 standard deviation, SD) and 42 Nold non-consanguineous caregivers (age: 70.6years±8.5 SD). In this procedure, spectral EEG coherence estimated reciprocal functional connectivity while non-normalized directed transfer function (NDTF) estimated effective connectivity. Principal component analysis and computation of Mahalanobis distance integrated and combined these EEG topographic markers of cortical connectivity. The area under receiver operating curve (AUC) indexed the classification accuracy. A good classification of Nold and AD individuals was obtained by combining the EEG markers derived from NDTF and coherence (AUC=86%, sensitivity=0.85, specificity=0.70). These encouraging results motivate a cross-validation study of the new procedure in age- and education-matched Nold, stable and progressing mild cognitive impairment individuals, and de novo AD patients with dementia. If cross-validated, the new procedure will provide cheap, broadly available, repeatable over time, and entirely non-invasive EEG topographic markers reflecting abnormal cortical connectivity in AD patients diagnosed by direct or indirect measurement of cerebral amyloid β and hyperphosphorylated tau peptides. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  20. The study of cognitive processes in the brain EEG during the perception of bistable images using wavelet skeleton

    NASA Astrophysics Data System (ADS)

    Runnova, Anastasiya E.; Zhuravlev, Maksim O.; Pysarchik, Alexander N.; Khramova, Marina V.; Grubov, Vadim V.

    2017-03-01

    In the paper we study the appearance of the complex patterns in human EEG data during a psychophysiological experiment by stimulating cognitive activity with the perception of ambiguous object. A new method based on the calculation of the maximum energy component for the continuous wavelet transform (skeletons) is proposed. Skeleton analysis allows us to identify specific patterns in the EEG data set, appearing in the perception of ambiguous objects. Thus, it becomes possible to diagnose some cognitive processes associated with the concentration of attention and recognition of complex visual objects. The article presents the processing results of experimental data for 6 male volunteers.

  1. EEG (Electroencephalogram)

    MedlinePlus

    ... caffeine on the day of the test, because caffeine can affect the test results. Take your usual medications unless instructed otherwise. If you're supposed to sleep during your EEG test, your doctor may ask ...

  2. Delayed Early Primary Visual Pathway Development in Premature Infants: High Density Electrophysiological Evidence

    PubMed Central

    Tremblay, Emmanuel; Vannasing, Phetsamone; Roy, Marie-Sylvie; Lefebvre, Francine; Kombate, Damelan; Lassonde, Maryse; Lepore, Franco; McKerral, Michelle; Gallagher, Anne

    2014-01-01

    In the past decades, multiple studies have been interested in developmental patterns of the visual system in healthy infants. During the first year of life, differential maturational changes have been observed between the Magnocellular (P) and the Parvocellular (P) visual pathways. However, few studies investigated P and M system development in infants born prematurely. The aim of the present study was to characterize P and M system maturational differences between healthy preterm and fullterm infants through a critical period of visual maturation: the first year of life. Using a cross-sectional design, high-density electroencephalogram (EEG) was recorded in 31 healthy preterms and 41 fullterm infants of 3, 6, or 12 months (corrected age for premature babies). Three visual stimulations varying in contrast and spatial frequency were presented to stimulate preferentially the M pathway, the P pathway, or both systems simultaneously during EEG recordings. Results from early visual evoked potentials in response to the stimulation that activates simultaneously both systems revealed longer N1 latencies and smaller P1 amplitudes in preterm infants compared to fullterms. Moreover, preterms showed longer N1 and P1 latencies in response to stimuli assessing the M pathway at 3 months. No differences between preterms and fullterms were found when using the preferential P system stimulation. In order to identify the cerebral generator of each visual response, distributed source analyses were computed in 12-month-old infants using LORETA. Source analysis demonstrated an activation of the parietal dorsal region in fullterm infants, in response to the preferential M pathway, which was not seen in the preterms. Overall, these findings suggest that the Magnocellular pathway development is affected in premature infants. Although our VEP results suggest that premature children overcome, at least partially, the visual developmental delay with time, source analyses reveal abnormal brain

  3. RETRACTED: Neutron scattering and molecular dynamics simulation studies of the phase transition: High-density amorphous ice to low-density amorphous ice

    NASA Astrophysics Data System (ADS)

    Dong, Shunle; Chen, Zhuo; Wang, Yan

    2010-03-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors of Chemical Physics. A large part of this article (text as well as measured data) has been published previously in Canadian Journal of Physics (Neutron-scattering studies of the phase transitions in high-pressure ices during annealing, by Y. Wang, A.I. Kolesnikov, S.L. Dong, and J.C. Li, Can. J. Phys., 81 (2003) 401-407, doi: 10.1139/p03-045).

  4. Safety and Biocompatibility of a New High-Density Polyethylene-Based Spherical Integrated Porous Orbital Implant: An Experimental Study in Rabbits

    PubMed Central

    Fernandez-Bueno, Ivan; Di Lauro, Salvatore; Alvarez, Ivan; Lopez, Jose Carlos; Garcia-Gutierrez, Maria Teresa; Fernandez, Itziar; Larra, Eva; Pastor, Jose Carlos

    2015-01-01

    Purpose. To evaluate clinically and histologically the safety and biocompatibility of a new HDPE-based spherical porous orbital implants in rabbits. Methods. MEDPOR (Porex Surgical, Inc., Fairburn, GA, USA), OCULFIT I, and OCULFIT II (AJL Ophthalmic S.A., Vitoria, Spain) implants were implanted in eviscerated rabbis. Animals were randomly divided into 6 groups (n = 4 each) according to the 3 implant materials tested and 2 follow-up times of 90 or 180 days. Signs of regional pain and presence of eyelid swelling, conjunctival hyperemia, and amount of exudate were semiquantitatively evaluated. After animals sacrifice, the implants and surrounding ocular tissues were processed for histological staining and polarized light evaluation. Statistical study was performed by ANOVA and Kaplan-Meier analysis. Results. No statistically significant differences in regional pain, eyelid swelling, or conjunctival hyperemia were shown between implants and/or time points evaluated. However, amount of exudate differed, with OCULFIT I causing the smallest amount. No remarkable clinical complications were observed. Histological findings were similar in all three types of implants and agree with minor inflammatory response. Conclusions. OCULFIT ophthalmic tolerance and biocompatibility in rabbits were comparable to the clinically used MEDPOR. Clinical studies are needed to determine if OCULFIT is superior to the orbital implants commercially available. PMID:26689343

  5. A genome-wide association study for somatic cell score using the Illumina high-density bovine beadchip identifies several novel QTL potentially related to mastitis susceptibility

    PubMed Central

    Meredith, Brian K.; Berry, Donagh P.; Kearney, Francis; Finlay, Emma K.; Fahey, Alan G.; Bradley, Daniel G.; Lynn, David J.

    2013-01-01

    Mastitis is an inflammation-driven disease of the bovine mammary gland that occurs in response to physical damage or infection and is one of the most costly production-related diseases in the dairy industry worldwide. We performed a genome-wide association study (GWAS) to identify genetic loci associated with somatic cell score (SCS), an indicator trait of mammary gland inflammation. A total of 702 Holstein-Friesian bulls were genotyped for 777,962 single nucleotide polymorphisms (SNPs) and associated with SCS phenotypes. The SCS phenotypes were expressed as daughter yield deviations (DYD) based on a large number of progeny performance records. A total of 138 SNPs on 15 different chromosomes reached genome-wide significance (corrected p-value ≤ 0.05) for association with SCS (after correction for multiple testing). We defined 28 distinct QTL regions and a number of candidate genes located in these QTL regions were identified. The most significant association (p-value = 1.70 × 10−7) was observed on chromosome 6. This QTL had no known genes annotated within it, however, the Ensembl Genome Browser predicted the presence of a small non-coding RNA (a Y RNA gene) in this genomic region. This Y RNA gene was 99% identical to human RNY4. Y RNAs are a rare type of non-coding RNA that were originally discovered due to their association with the autoimmune disease, systemic lupus erythematosus. Examining small-RNA sequencing (RNAseq) data being generated by us in multiple different mastitis-pathogen challenged cell-types has revealed that this Y RNA is expressed (but not differentially expressed) in these cells. Other QTL regions identified in this study also encoded strong candidate genes for mastitis susceptibility. A QTL region on chromosome 13, for example, was found to contain a cluster of β-defensin genes, a gene family with known roles in innate immunity. Due to the increased SNP density, this study also refined the boundaries for several known QTL for SCS and

  6. A Study to Analyze the Permeation of High Density Gases and Propellant Vapors Through Single Layer Teflon or Teflon Structure Materials and Laminations. Volume 1

    NASA Technical Reports Server (NTRS)

    Johnson, R. L.; Young, Donald L. (Technical Monitor)

    1967-01-01

    This report contains the results of a fifteen month analytical and experimental study of the leakage rate of the pressurant gases (N2, He) and the propellant vapors (N2O4,N2H4) through bladder structures consisting of two layers of Teflon separated by a metallic foil diffusion barrier containing microscopic or larger holes. Results were obtained for the steady state leakage rate through circular holes and long rectangular openings in the barrier for arbitrary thicknesses of the two Teflon layers. The effect of hole shape and relative hole position on the leakage rate were studied. The transient problem was analyzed and it was shown that steady state calculations are adequate for estimating the leakage rate. A computer program entitled "Diffusion Analyzer Program" was developed to calculate the leakage rate, both transient and steady state. Finally, the analytical results were compared to experimentally determined values of the leakage rate through a model laminated bladder structure. The results of the analysis are in good agreement with experiment. The experimental effort (Part II of the Bladder Permeation Program) measured the solubility, diffusion coefficient and permeability of helium, nitrogen and nitrogen tetroxide vapor through Teflon TFE and FEP membranes. Data were obtained in the temperature range of 25 to 100 C at pressures ranging from near vacuum to about 20 atmospheres. Results of the experimental effort were compared with the limited data previously reported. As a verification to the applicability of results to actual bladder systems, counter diffusion tests were performed with a laminated sample containing aluminum foil with a selected group of holes.

  7. Meson Masses in High Density QCD

    SciTech Connect

    Silas R. Beane; Paulo F. Bedaque; Martin J. Savage

    2000-06-15

    The low-energy effective theories for the two- and three-flavor color-superconductors arising in the high density limit of QCD are discussed. Using an effective field theory to describe quarks near the fermi surface, we compute the masses of the pseudo-Goldstone bosons that dominate the low-momentum dynamics of these systems.

  8. Unconventional High Density Vertically Aligned Conducting Polymer

    DTIC Science & Technology

    2014-08-21

    CVD) method on silicon substrates using iron (Fe) on alumina as a catalyst . The as-grown A-CNT forests have a 1% volume fraction (Vf) of CNTs with...here, consisting of the anode of the conformal coating of oCVD PEDOT on A-CNTs (PEDOT/A-CNTs) and ultra-high density graphene-oxide cathode ( HD -a

  9. Supernovae and high density nuclear matter

    SciTech Connect

    Kahana, S.

    1986-01-01

    The role of the nuclear equation of state (EOS) in producing prompt supernova explosions is examined. Results of calculations of Baron, Cooperstein, and Kahana incorporating general relativity and a new high density EOS are presented, and the relevance of these calculations to laboratory experiments with heavy ions considered. 31 refs., 6 figs., 2 tabs.

  10. High density laser-driven target

    DOEpatents

    Lindl, John D.

    1981-01-01

    A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

  11. Approach of high density coal preparation method

    SciTech Connect

    Yang, Y.; Chen, Q.

    1996-12-31

    Density difference of aged anthracite coal of high density and discard is less than that of general coal and discard; conventional separation methods are difficult to be used. For the special coal, coal dry beneficiation technology with air-dense medium fluidized bed has obvious superiority over other separation methods.

  12. Changes in triglycerides and high-density lipoprotein cholesterol may precede peripheral insulin resistance, with 2-h insulin partially mediating this unidirectional relationship: a prospective cohort study.

    PubMed

    Han, Tianshu; Cheng, Yu; Tian, Shuang; Wang, Li; Liang, Xi; Duan, Wei; Na, Lixin; Sun, Changhao

    2016-11-04

    Results of longitudinal researches regarding the temporal relationship between dyslipidemia and insulin resistance (IR) are inconsistent. This study assessed temporal relationships of blood lipids with IR and determined whether there are any mediating effects existed in these temporal relationships. This study examined a longitudinal cohort of 3325 subjects aged 20-74 years from China with an average of 4.2 years follow-up. Measurements of fasting blood lipids, as well as fasting and 2-h serum glucose and insulin, were obtained at two time points. The Gutt index and HOMA-IR were calculated as indicators of peripheral IR and hepatic IR. A cross-lagged path analysis was performed to examine the temporal relationships between blood lipids and IR. A mediation analysis was used to examine mediating effect. After adjusting for covariates, the cross-lagged path coefficients from baseline TG and HDL-C to follow-up Gutt index were significantly greater than those from baseline Gutt index to follow-up TG and HDL-C (β1 = -0.131 vs β2 = -0.047, P < 0.001 for TG; β1 = 0.134 vs β2 = 0.023, P < 0.001 for HDL-C). The path coefficients from baseline TG and HDL-C to follow-up 2-h insulin were significantly greater than those from baseline 2-h insulin to follow-up TG and HDL-C (β1 = 0.125 vs β2 = 0.040, P < 0.001 for TG; β1 = -0.112 vs β2 = -0.026, P < 0.001 for HDL-C). 2-h insulin partially mediated the effect of TG/HDL-C on Gutt index with a 59.3% mediating effect for TG and 61.0% for HDL-C. These findings provide strong evidence that dyslipidemia probably precede peripheral IR and that 2-h insulin partially mediates this unidirectional temporal relationship.

  13. High-density lipoprotein subclasses are a potential intermediary between alcohol intake and reduced risk of cardiovascular disease: the Rancho Bernardo Study.

    PubMed

    Muth, Natalie D; Laughlin, Gail A; von Mühlen, Denise; Smith, Sidney C; Barrett-Connor, Elizabeth

    2010-10-01

    We conducted a cross-sectional study of NMR-derived HDL subclasses and alcohol intake among 2171 community-dwelling older adults with a large proportion of daily or near-daily alcohol consumers (44 %). We aimed to assess whether, in addition to increasing total HDL, alcohol may induce a beneficial shift in HDL particle size distribution. Participants were categorised based on reported alcohol intake (g per week) and on frequency (none, < 3 times/week, 3-4 times/week, ≥ 5 times/week). The association between alcohol intake and lipoprotein fractions was examined using sex-specific linear regression models adjusted for age, BMI, diabetes, current smoking, exercise and hormone therapy in women. There was a stepwise gradient with the highest weekly alcohol consumption associated with the highest total HDL size and greatest number of medium and large HDL particles, as well as higher total HDL concentrations (all P < 0.001); total small HDL did not differ. Alcohol-HDL size associations were similar in both sexes and did not differ by use of hormone replacement therapy in women. In conclusion, regular alcohol consumers had a higher number and percentage of large HDL particles than non-drinkers. These results suggest that one way that alcohol may decrease CVD is through potentially favourable changes in lipoprotein subclass composition.

  14. High-density Genotyping of Immune Loci in Kawasaki Disease and IVIG Treatment Response in European-American Case-parent Trio Study

    PubMed Central

    Shendre, Aditi; Wiener, Howard W.; Zhi, Degui; Vazquez, Ana I; Portman, Michael A.; Shrestha, Sadeep

    2014-01-01

    Kawasaki disease (KD) is a diffuse and acute small-vessel vasculitis observed in children and has genetic and autoimmune components. We genotyped 112 case-parent trios of European decent (confirmed by AIMS) using the ImmunoChip array and performed association analyses with susceptibility to KD and IVIG non-response. KD susceptibility was assessed using the transmission disequilibrium test whereas IVIG non-response was evaluated using multivariable logistic regression analysis. We replicated SNPs in three gene regions (FCGR, CD40/CDH22, and HLA-DQB2/HLA-DOB) that have been previously associated with KD and provide support to other findings of several novel SNPs in genes with potential pathway in KD pathogenesis. SNP rs838143 in the 3′ UTR of FUT1 gene (2.7×10-5) and rs9847915 in the intergenic region of LOC730109 ∣ BRD7P2 (6.81×10-7) were the top hits for KD susceptibility in additive and dominant models, respectively. The top hits for IVIG responsiveness were rs1200332 in the intergenic region of BAZ1A ∣ C14orf19 (1.4×10-4) and rs4889606 in the intron of the STX1B gene (6.95×10-5) in additive and dominant models, respectively. Our study suggests that genes and biological pathways involved in autoimmune diseases play an important role in the pathogenesis of KD and IVIG response mechanism. PMID:25101798

  15. A Whole Genome Association Study on Meat Quality Traits Using High Density SNP Chips in a Cross between Korean Native Pig and Landrace.

    PubMed

    Lee, K-T; Lee, Y-M; Alam, M; Choi, B H; Park, M R; Kim, K-S; Kim, T-H; Kim, J-J

    2012-11-01

    A whole genome association (WGA) study was performed to detect significant polymorphisms for meat quality traits in an F2 cross population (N = 478) that were generated with Korean native pig sires and Landrace dams in National Livestock Research Institute, Songwhan, Korea. The animals were genotyped using Illumina porcine 60k SNP beadchips, in which a set of 46,865 SNPs were available for the WGA analyses on ten carcass quality traits; live weight, crude protein, crude lipids, crude ash, water holding capacity, drip loss, shear force, CIE L, CIE a and CIE b. Phenotypes were regressed on additive and dominance effects for each SNP using a simple linear regression model, after adjusting for sex, sire and slaughter stage as fixed effects. With the significant SNPs for each trait (p<0.001), a stepwise regression procedure was applied to determine the best set of SNPs with the additive and/or dominance effects. A total of 106 SNPs, or quantitative trait loci (QTL) were detected, and about 32 to 66% of the total phenotypic variation was explained by the significant SNPs for each trait. The QTL were identified in most porcine chromosomes (SSCs), in which majority of the QTL were detected in SSCs 1, 2, 12, 13, 14 and 16. Several QTL clusters were identified on SSCs 12, 16 and 17, and a cluster of QTL influencing crude protein, crude lipid, drip loss, shear force, CIE a and CIE b were located between 20 and 29 Mb of SSC12. A pleiotropic QTL for drip loss, CIE L and CIE b was also detected on SSC16. These QTL need to be validated in commercial pig populations for genetic improvement in meat quality via marker-assisted selection.

  16. High-density scintillating glasses for a proton imaging detector

    NASA Astrophysics Data System (ADS)

    Tillman, I. J.; Dettmann, M. A.; Herrig, V.; Thune, Z. L.; Zieser, A. J.; Michalek, S. F.; Been, M. O.; Martinez-Szewczyk, M. M.; Koster, H. J.; Wilkinson, C. J.; Kielty, M. W.; Jacobsohn, L. G.; Akgun, U.

    2017-06-01

    High-density scintillating glasses are proposed for a novel proton-imaging device that can improve the accuracy of the hadron therapy. High-density scintillating glasses are needed to build a cost effective, compact calorimeter that can be attached to a gantry. This report summarizes the study on Europium, Terbium, and Cerium-doped scintillating glasses that were developed containing heavy elements such as Lanthanum, Gadolinium, and Tungsten. The density of the samples reach up to 5.9 g/cm3, and their 300-600 nm emission overlaps perfectly with the peak cathode sensitivity of the commercial photo detectors. The developed glasses do not require any special quenching and can be poured easily, which makes them a good candidate for production in various geometries. Here, the glass making conditions, preliminary tests on optical and physical properties of these scintillating, high-density, oxide glasses developed for a novel medical imaging application are reported.

  17. [The EEG and thinking].

    PubMed

    Petsche, H

    1990-12-01

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

  18. EEG Abnormalities Are Associated With Poorer Depressive Symptom Outcomes With Escitalopram and Venlafaxine-XR, but Not Sertraline: Results From the Multicenter Randomized iSPOT-D Study.

    PubMed

    Arns, Martijn; Gordon, Evian; Boutros, Nash N

    2017-01-01

    Rationale Limited research is available on electrophysiological abnormalities such as epileptiform EEG or EEG slowing in depression and its association with antidepressant treatment response. Objectives We investigated the association between EEG abnormalities and antidepressant treatment response in the international Study to Predict Optimized Treatment in Depression (iSPOT-D). Methods Of 1008 participants with major depressive disorder randomized to escitalopram, sertraline, or venlafaxine-XR, 622 completed 8 weeks of treatment per protocol. The study also recruited 336 healthy controls. Treatment response was established after 8 weeks using the 17-item Hamilton Rating Scale for Depression (HRSD17). The resting-state EEG was assessed at baseline with eyes closed. EEG abnormalities including epileptiform activity, EEG slowing, and alpha peak frequency (APF) were scored for all subjects, blind to treatment outcome. Results Patients and controls did not differ in the occurrence of EEG abnormalities. Furthermore, in the per protocol sample the occurrence of epileptiform EEG and EEG slowing (as a combined marker) were associated with a reduced likelihood of responding to escitalopram (P = .019; odds ratio [OR] = 3.56) and venlafaxine-XR (P = .043; OR = 2.76), but not sertraline (OR = 0.73). The response rates for this "any EEG abnormality" groups versus the "no-abnormality" group were 33% and 64% for escitalopram and 41% and 66% for venlafaxine-XR, respectively. A slow APF was associated with treatment response only in the sertraline group (P = .21; d = .027). Conclusions EEG abnormalities are associated with nonresponse to escitalopram and venlafaxine-XR, but not sertraline, whereas a slow APF is associated to response for sertraline only.

  19. Disrupted reinforcement learning and maladaptive behavior in women with a history of childhood sexual abuse: a high-density event-related potential study.

    PubMed

    Pechtel, Pia; Pizzagalli, Diego A

    2013-05-01

    previously rewarded, but not previously punished, trials. Irrespective of past MDD episodes, women with a history of CSA showed neural and behavioral deficits in utilizing previous reinforcement to optimize decision making in the absence of feedback (blunted "Go learning"). Although our study provides initial evidence for reward-specific deficits associated with CSA, future research is warranted to determine if disrupted positive reinforcement learning predicts high-risk behavior following CSA.

  20. Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium

    PubMed Central

    Lu, Yingchang; Justice, Anne E.; Mudgal, Poorva; Liu, Ching-Ti; Young, Kristin; Feitosa, Mary F.; Rand, Kristin; Dimitrov, Latchezar; Duan, Qing; Guo, Xiuqing; Lange, Leslie A.; Nalls, Michael A.; Okut, Hayrettin; Tayo, Bamidele O.; Vedantam, Sailaja; Bradfield, Jonathan P.; Chen, Guanjie; Chesi, Alessandra; Irvin, Marguerite R.; Padhukasahasram, Badri; Zheng, Wei; Allison, Matthew A.; Ambrosone, Christine B.; Bandera, Elisa V.; Berndt, Sonja I.; Blot, William J.; Bottinger, Erwin P.; Carpten, John; Chanock, Stephen J.; Chen, Yii-Der Ida; Conti, David V.; Cooper, Richard S.; Fornage, Myriam; Freedman, Barry I.; Garcia, Melissa; Goodman, Phyllis J.; Hsu, Yu-Han H.; Hu, Jennifer; Huff, Chad D.; Ingles, Sue A.; John, Esther M.; Kittles, Rick; Klein, Eric; Li, Jin; McKnight, Barbara; Nayak, Uma; Nemesure, Barbara; Olshan, Andrew; Salako, Babatunde; Sanderson, Maureen; Shao, Yaming; Siscovick, David S.; Stanford, Janet L.; Strom, Sara S.; Witte, John S.; Yao, Jie; Zhu, Xiaofeng; Ziegler, Regina G.; Zonderman, Alan B.; Ambs, Stefan; Cushman, Mary; Faul, Jessica D.; Hakonarson, Hakon; Levin, Albert M.; Nathanson, Katherine L.; Weir, David R.; Zhi, Degui; Arnett, Donna K.; Kardia, Sharon L. R.; Oloapde, Olufunmilayo I.; Rao, D. C.; Williams, L. Keoki; Becker, Diane M.; Borecki, Ingrid B.; Evans, Michele K.; Harris, Tamara B.; Hirschhorn, Joel N.; Psaty, Bruce M.; Wilson, James G.; Bowden, Donald W.; Cupples, L. Adrienne; Haiman, Christopher A.; Loos, Ruth J. F.; North, Kari E.

    2017-01-01

    Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P < 5×10−8: seven for BMI, and one for WHRadjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHRadjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in

  1. Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium.

    PubMed

    Ng, Maggie C Y; Graff, Mariaelisa; Lu, Yingchang; Justice, Anne E; Mudgal, Poorva; Liu, Ching-Ti; Young, Kristin; Yanek, Lisa R; Feitosa, Mary F; Wojczynski, Mary K; Rand, Kristin; Brody, Jennifer A; Cade, Brian E; Dimitrov, Latchezar; Duan, Qing; Guo, Xiuqing; Lange, Leslie A; Nalls, Michael A; Okut, Hayrettin; Tajuddin, Salman M; Tayo, Bamidele O; Vedantam, Sailaja; Bradfield, Jonathan P; Chen, Guanjie; Chen, Wei-Min; Chesi, Alessandra; Irvin, Marguerite R; Padhukasahasram, Badri; Smith, Jennifer A; Zheng, Wei; Allison, Matthew A; Ambrosone, Christine B; Bandera, Elisa V; Bartz, Traci M; Berndt, Sonja I; Bernstein, Leslie; Blot, William J; Bottinger, Erwin P; Carpten, John; Chanock, Stephen J; Chen, Yii-Der Ida; Conti, David V; Cooper, Richard S; Fornage, Myriam; Freedman, Barry I; Garcia, Melissa; Goodman, Phyllis J; Hsu, Yu-Han H; Hu, Jennifer; Huff, Chad D; Ingles, Sue A; John, Esther M; Kittles, Rick; Klein, Eric; Li, Jin; McKnight, Barbara; Nayak, Uma; Nemesure, Barbara; Ogunniyi, Adesola; Olshan, Andrew; Press, Michael F; Rohde, Rebecca; Rybicki, Benjamin A; Salako, Babatunde; Sanderson, Maureen; Shao, Yaming; Siscovick, David S; Stanford, Janet L; Stevens, Victoria L; Stram, Alex; Strom, Sara S; Vaidya, Dhananjay; Witte, John S; Yao, Jie; Zhu, Xiaofeng; Ziegler, Regina G; Zonderman, Alan B; Adeyemo, Adebowale; Ambs, Stefan; Cushman, Mary; Faul, Jessica D; Hakonarson, Hakon; Levin, Albert M; Nathanson, Katherine L; Ware, Erin B; Weir, David R; Zhao, Wei; Zhi, Degui; Arnett, Donna K; Grant, Struan F A; Kardia, Sharon L R; Oloapde, Olufunmilayo I; Rao, D C; Rotimi, Charles N; Sale, Michele M; Williams, L Keoki; Zemel, Babette S; Becker, Diane M; Borecki, Ingrid B; Evans, Michele K; Harris, Tamara B; Hirschhorn, Joel N; Li, Yun; Patel, Sanjay R; Psaty, Bruce M; Rotter, Jerome I; Wilson, James G; Bowden, Donald W; Cupples, L Adrienne; Haiman, Christopher A; Loos, Ruth J F; North, Kari E

    2017-04-01

    Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P < 5×10-8: seven for BMI, and one for WHRadjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHRadjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in

  2. Multidimensional cognitive evaluation of patients with disorders of consciousness using EEG: A proof of concept study.

    PubMed

    Sergent, Claire; Faugeras, Frédéric; Rohaut, Benjamin; Perrin, Fabien; Valente, Mélanie; Tallon-Baudry, Catherine; Cohen, Laurent; Naccache, Lionel

    2017-01-01

    The use of cognitive evoked potentials in EEG is now part of the routine evaluation of non-communicating patients with disorders of consciousness in several specialized medical centers around the world. They typically focus on one or two cognitive markers, such as the mismatch negativity or the P3 to global auditory regularity. However it has become clear that none of these markers in isolation is at the same time sufficiently specific and sufficiently sensitive to be taken as the unique gold standard for diagnosing consciousness. A good way forward would be to combine several cognitive markers within the same test to improve evaluation. Furthermore, given the diversity of lesions leading to disorders of consciousness, it is important not only to probe whether a patient is conscious or not, but also to establish a more general and nuanced profile of the residual cognitive capacities of each patient using a combination of markers. In the present study we built a unique EEG protocol that probed 8 dimensions of cognitive processing in a single 1.5 h session. This protocol probed variants of classical markers together with new markers of spatial attention, which has not yet been studied in these patients. The eight dimensions were: (1) own name recognition, (2) temporal attention, (3) spatial attention, (4) detection of spatial incongruence (5) motor planning, and (6,7,8) modulations of these effects by the global context, reflecting higher-level functions. This protocol was tested in 15 healthy control subjects and in 17 patients with various etiologies, among which 13 could be included in the analysis. The results in the control group allowed a validation and a specific description of the cognitive levels probed by each marker. At the single-subject level, this combined protocol allowed assessing the presence of both classical and newly introduced markers for each patient and control, and revealed that the combination of several markers increased diagnostic

  3. Signal distortion from microelectrodes in clinical EEG acquisition systems

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

    Many centers are now using high-density microelectrodes during traditional intracranial electroencephalography (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 GΩ, which is much higher than most clinical systems. These results show that it is critical to account for variations

  4. Cognitive workload modulation through degraded visual stimuli: a single-trial EEG study

    NASA Astrophysics Data System (ADS)

    Yu, K.; Prasad, I.; Mir, H.; Thakor, N.; Al-Nashash, H.

    2015-08-01

    Objective. Our experiments explored the effect of visual stimuli degradation on cognitive workload. Approach. We investigated the subjective assessment, event-related potentials (ERPs) as well as electroencephalogram (EEG) as measures of cognitive workload. Main results. These experiments confirm that degradation of visual stimuli increases cognitive workload as assessed by subjective NASA task load index and confirmed by the observed P300 amplitude attenuation. Furthermore, the single-trial multi-level classification using features extracted from ERPs and EEG is found to be promising. Specifically, the adopted single-trial oscillatory EEG/ERP detection method achieved an average accuracy of 85% for discriminating 4 workload levels. Additionally, we found from the spatial patterns obtained from EEG signals that the frontal parts carry information that can be used for differentiating workload levels. Significance. Our results show that visual stimuli can modulate cognitive workload, and the modulation can be measured by the single trial EEG/ERP detection method.

  5. Joint Coupling of Awake EEG Frequency Activity and MRI Gray Matter Volumes in the Psychosis Dimension: A BSNIP Study.

    PubMed

    Soh, Pauline; Narayanan, Balaji; Khadka, Sabin; Calhoun, Vince D; Keshavan, Matcheri S; Tamminga, Carol A; Sweeney, John A; Clementz, Brett A; Pearlson, Godfrey D

    2015-01-01

    Many studies have examined either electroencephalogram (EEG) frequency activity or gray matter volumes (GMV) in various psychoses [including schizophrenia (SZ), schizoaffective (SZA), and psychotic bipolar disorder (PBP)]. Prior work demonstrated similar EEG and gray matter abnormalities in both SZ and PBP. Integrating EEG and GMV and jointly analyzing the combined data fully elucidates the linkage between the two and may provide better biomarker- or endophenotype-specificity for a particular illness. Joint exploratory investigations of EEG and GMV are scarce in the literature and the relationship between the two in psychosis is even less explored. We investigated a joint multivariate model to test whether the linear relationship or linkage between awake EEG (AEEG) frequency activity and GMV is abnormal across the psychosis dimension and if such effects are also present in first-degree relatives. We assessed 607 subjects comprising 264 probands [105 SZ, 72 SZA, and 87 PBP], 233 of their first degree relatives [82 SZ relatives (SZR), 71 SZA relatives (SZAR), and 80 PBP relatives (PBPR)], and 110 healthy comparison subjects (HC). All subjects underwent structural MRI (sMRI) and EEG scans. Frequency activity and voxel-based morphometric GMV were derived from EEG and sMRI data, respectively. Seven AEEG frequency and gray matter components were extracted using Joint independent component analysis (jICA). The loading coefficients (LC) were examined for group differences using analysis of covariance. Further, the LCs were correlated with psychopathology scores to identify relationship with clinical symptoms. Joint ICA revealed a single component differentiating SZ from HC (p < 0.006), comprising increased posterior alpha activity associated with decreased volume in inferior parietal lobe, supramarginal, parahippocampal gyrus, middle frontal, inferior temporal gyri, and increased volume of uncus and culmen. No components were aberrant in either PBP or SZA or any

  6. Epileptogenic networks of type II focal cortical dysplasia: a stereo-EEG study.

    PubMed

    Varotto, Giulia; Tassi, Laura; Franceschetti, Silvana; Spreafico, Roberto; Panzica, Ferruccio

    2012-07-02

    In the context of focal and drug-resistant epilepsy, surgical resection of the epileptogenic zone may be the only therapeutic option for reducing or suppressing seizures. In many such patients, intracranial stereo-EEG recordings remain the gold standard for the epilepsy surgery work-up. Assessing the extent of the epileptogenic zone and its organisation is a crucial objective, and requires advanced methods of signal processing. Over the last ten years, considerable efforts have been made to develop signal analysis techniques for characterising the connectivity between spatially distributed regions. The aim of this study was to evaluate the changes in dynamic connectivity pattern under inter-ictal, pre-ictal and ictal conditions using signals derived from stereo-EEG recordings of 10 patients with Taylor-type focal cortical dysplasia. A causal linear multivariate method - partial directed coherence - and indices derived from graph theory were used to characterise the synchronisation property of the lesional zone (corresponding to the epileptogenic zone in our patients) and to distinguish it from other regions involved in ictal activity or not. The results show that a significantly different connectivity pattern (mainly in the gamma band) distinguishes the epileptogenic zone from other cortical regions not only during the ictal event, but also during the inter- and pre-ictal periods. This indicates that the lesional nodes play a leading role in generating and propagating ictal EEG activity by acting as the hubs of the epileptic network originating and sustaining seizures. Our findings also indicate that the cortical regions beyond the dysplasia involved in the ictal activity essentially act as "secondary" generators of synchronous activity. The leading role of the lesional zone may account for the good post-surgical outcome of patients with type II focal cortical dysplasia as resecting the dysplasia removes the epileptogenic zone responsible for seizure organisation

  7. High density tape/head interface study

    NASA Technical Reports Server (NTRS)

    Csengery, L. C.

    1983-01-01

    The high energy (H sub c approximately or = to 650 oersteds) tapes and high track density (84 tracks per inch) heads investigated had, as its goal, the definition of optimum combinations of head and tape, including the control required of their interfacial dynamics that would enable the manufacture of high rate (150 Mbps) digital tape recorders for unattended space flight.

  8. High Density Lipoprotein Metabolism in Man

    PubMed Central

    Blum, Conrad B.; Levy, Robert I.; Eisenberg, Shlomo; Hall, Marshall; Goebel, Robert H.; Berman, Mones

    1977-01-01

    The turnover of 125I-high density lipoprotein (HDL) was examined in a total of 14 studies in eight normal volunteers in an attempt to determine the metabolic relationship between apolipoproteins A-I (apoA-I) and A-II (apoA-II) of HDL and to define further some of the determinants of HDL metabolism. All subjects were first studied under conditions of an isocaloric balanced diet (40% fat, 40% carbohydrate). Four were then studied with an 80% carbohydrate diet, and two were studied while receiving nicotinic acid (1 g three times daily) and ingesting the same isocaloric balanced diet. The