Science.gov

Sample records for promotes eeg theta

  1. Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding.

    PubMed

    Kirov, Roumen; Weiss, Carsten; Siebner, Hartwig R; Born, Jan; Marshall, Lisa

    2009-09-08

    The application of transcranial slow oscillation stimulation (tSOS; 0.75 Hz) was previously shown to enhance widespread endogenous EEG slow oscillatory activity when applied during a sleep period characterized by emerging endogenous slow oscillatory activity. Processes of memory consolidation typically occurring during this state of sleep were also enhanced. Here, we show that the same tSOS applied in the waking brain also induced an increase in endogenous EEG slow oscillations (0.4-1.2 Hz), although in a topographically restricted fashion. Applied during wakefulness tSOS, additionally, resulted in a marked and widespread increase in EEG theta (4-8 Hz) activity. During wake, tSOS did not enhance consolidation of memories when applied after learning, but improved encoding of hippocampus-dependent memories when applied during learning. We conclude that the EEG frequency and related memory processes induced by tSOS critically depend on brain state. In response to tSOS during wakefulness the brain transposes stimulation by responding preferentially with theta oscillations and facilitated encoding.

  2. Modulation of EEG Theta Band Signal Complexity by Music Therapy

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Joydeep; Lee, Eun-Jeong

    The primary goal of this study was to investigate the impact of monochord (MC) sounds, a type of archaic sounds used in music therapy, on the neural complexity of EEG signals obtained from patients undergoing chemotherapy. The secondary goal was to compare the EEG signal complexity values for monochords with those for progressive muscle relaxation (PMR), an alternative therapy for relaxation. Forty cancer patients were randomly allocated to one of the two relaxation groups, MC and PMR, over a period of six months; continuous EEG signals were recorded during the first and last sessions. EEG signals were analyzed by applying signal mode complexity, a measure of complexity of neuronal oscillations. Across sessions, both groups showed a modulation of complexity of beta-2 band (20-29Hz) at midfrontal regions, but only MC group showed a modulation of complexity of theta band (3.5-7.5Hz) at posterior regions. Therefore, the neuronal complexity patterns showed different changes in EEG frequency band specific complexity resulting in two different types of interventions. Moreover, the different neural responses to listening to monochords and PMR were observed after regular relaxation interventions over a short time span.

  3. Differential effects of ongoing EEG beta and theta power on memory formation

    PubMed Central

    Scholz, Sebastian; Schneider, Signe Luisa

    2017-01-01

    Recently, elevated ongoing pre-stimulus beta power (13–17 Hz) at encoding has been associated with subsequent memory formation for visual stimulus material. It is unclear whether this activity is merely specific to visual processing or whether it reflects a state facilitating general memory formation, independent of stimulus modality. To answer that question, the present study investigated the relationship between neural pre-stimulus oscillations and verbal memory formation in different sensory modalities. For that purpose, a within-subject design was employed to explore differences between successful and failed memory formation in the visual and auditory modality. Furthermore, associative memory was addressed by presenting the stimuli in combination with background images. Results revealed that similar EEG activity in the low beta frequency range (13–17 Hz) is associated with subsequent memory success, independent of stimulus modality. Elevated power prior to stimulus onset differentiated successful from failed memory formation. In contrast, differential effects between modalities were found in the theta band (3–7 Hz), with an increased oscillatory activity before the onset of later remembered visually presented words. In addition, pre-stimulus theta power dissociated between successful and failed encoding of associated context, independent of the stimulus modality of the item itself. We therefore suggest that increased ongoing low beta activity reflects a memory promoting state, which is likely to be moderated by modality-independent attentional or inhibitory processes, whereas high ongoing theta power is suggested as an indicator of the enhanced binding of incoming interlinked information. PMID:28192459

  4. EEG oscillations and recognition memory: theta correlates of memory retrieval and decision making.

    PubMed

    Jacobs, Joshua; Hwang, Grace; Curran, Tim; Kahana, Michael J

    2006-08-15

    Studies of memory retrieval have identified electroencephalographic (EEG) correlates of a test item's old-new status, reaction time, and memory load. In the current study, we used a multivariate analysis to disentangle the effects of these correlated variables. During retrieval, power of left-parietal theta (4-8 Hz) oscillations increased in proportion to how well a test item was remembered, and theta in central regions correlated with decision making. We also studied how these oscillatory dynamics complemented event-related potentials. These findings are the first to demonstrate that distinct patterns of theta oscillations can simultaneously relate to different aspects of behavior.

  5. EEG Theta and Gamma Responses to Semantic Violations in Online Sentence Processing

    ERIC Educational Resources Information Center

    Hald, Lea A.; Bastiaansen, Marcel C. M.; Hagoort, Peter

    2006-01-01

    We explore the nature of the oscillatory dynamics in the EEG of subjects reading sentences that contain a semantic violation. More specifically, we examine whether increases in theta ([Approximately]3-7 Hz) and gamma (around 40 Hz) band power occur in response to sentences that were either semantically correct or contained a semantically…

  6. A Decade of EEG Theta/Beta Ratio Research in ADHD: A Meta-Analysis

    ERIC Educational Resources Information Center

    Arns, Martijn; Conners, C. Keith; Kraemer, Helena C.

    2013-01-01

    Objective: Many EEG studies have reported that ADHD is characterized by elevated Theta/Beta ratio (TBR). In this study we conducted a meta-analysis on the TBR in ADHD. Method: TBR data during Eyes Open from location Cz were analyzed from children/adolescents 6-18 years of age with and without ADHD. Results: Nine studies were identified with a…

  7. Resting-state EEG theta activity and risk learning: sensitivity to reward or punishment?

    PubMed

    Massar, Stijn A A; Kenemans, J Leon; Schutter, Dennis J L G

    2014-03-01

    Increased theta (4-7 Hz)-beta (13-30 Hz) power ratio in resting state electroencephalography (EEG) has been associated with risky disadvantageous decision making and with impaired reinforcement learning. However, the specific contributions of theta and beta power in risky decision making remain unclear. The first aim of the present study was to replicate the earlier found relationship and examine the specific contributions of theta and beta power in risky decision making using the Iowa Gambling Task. The second aim of the study was to examine whether the relation were associated with differences in reward or punishment sensitivity. We replicated the earlier found relationship by showing a positive association between theta/beta ratio and risky decision making. This correlation was mainly driven by theta oscillations. Furthermore, theta power correlated with reward motivated learning, but not with punishment learning. The present results replicate and extend earlier findings by providing novel insights into the relation between thetabeta ratios and risky decision making. Specifically, findings show that resting-state theta activity is correlated with reinforcement learning, and that this association may be explained by differences in reward sensitivity.

  8. Genetic variability in the human cannabinoid receptor 1 is associated with resting state EEG theta power in humans.

    PubMed

    Heitland, I; Kenemans, J L; Böcker, K B E; Baas, J M P

    2014-11-01

    It has long been postulated that exogenous cannabinoids have a profound effect on human cognitive functioning. These cannabinoid effects are thought to depend, at least in parts, on alterations of phase-locking of local field potential neuronal firing. The latter can be measured as activity in the theta frequency band (4-7Hz) by electroencephalogram. Theta oscillations are supposed to serve as a mechanism in neural representations of behaviorally relevant information. However, it remains unknown whether variability in endogenous cannabinoid activity is involved in theta rhythms and therefore, may serve as an individual differences index of human cognitive functioning. To clarify this issue, we recorded resting state EEG activity in 164 healthy human subjects and extracted EEG power across frequency bands (δ, θ, α, and β). To assess variability in the endocannabinoid system, two genetic polymorphisms (rs1049353, rs2180619) within the cannabinoid receptor 1 (CB1) were determined in all participants. As expected, we observed significant effects of rs1049353 on EEG power in the theta band at frontal, central and parietal electrode regions. Crucially, these effects were specific for the theta band, with no effects on activity in the other frequency bands. Rs2180619 showed no significant associations with theta power after Bonferroni correction. Taken together, we provide novel evidence in humans showing that genetic variability in the cannabinoid receptor 1 is associated with resting state EEG power in the theta frequency band. This extends prior findings of exogenous cannabinoid effects on theta power to the endogenous cannabinoid system.

  9. EEG synchronization characteristics of functional connectivity and complex network properties of memory maintenance in the delta and theta frequency bands.

    PubMed

    Tóth, Brigitta; Boha, Roland; Pósfai, Márton; Gaál, Zsófia Anna; Kónya, Anikó; Stam, Cornelis Jan; Molnár, Márk

    2012-03-01

    Task-dependent changes of nonlinear-linear synchronization features and graph theoretical properties of the delta and theta frequencies were analyzed in the present EEG study that were related to episodic memory maintenance processes. Synchronization was found to increase with respect to both the delta and theta bands within the frontal and parietal areas and also between these regions. Results of graph theoretical analysis indicated a task-related shift towards small-world network topology in the theta band.

  10. Theta-alpha EEG phase distributions in the frontal area for dissociation of visual and auditory working memory

    PubMed Central

    Akiyama, Masakazu; Tero, Atsushi; Kawasaki, Masahiro; Nishiura, Yasumasa; Yamaguchi, Yoko

    2017-01-01

    Working memory (WM) is known to be associated with synchronization of the theta and alpha bands observed in electroencephalograms (EEGs). Although frontal-posterior global theta synchronization appears in modality-specific WM, local theta synchronization in frontal regions has been found in modality-independent WM. How frontal theta oscillations separately synchronize with task-relevant sensory brain areas remains an open question. Here, we focused on theta-alpha phase relationships in frontal areas using EEG, and then verified their functional roles with mathematical models. EEG data showed that the relationship between theta (6 Hz) and alpha (12 Hz) phases in the frontal areas was about 1:2 during both auditory and visual WM, and that the phase distributions between auditory and visual WM were different. Next, we used the differences in phase distributions to construct FitzHugh-Nagumo type mathematical models. The results replicated the modality-specific branching by orthogonally of the trigonometric functions for theta and alpha oscillations. Furthermore, mathematical and experimental results were consistent with regards to the phase relationships and amplitudes observed in frontal and sensory areas. These results indicate the important role that different phase distributions of theta and alpha oscillations have in modality-specific dissociation in the brain. PMID:28266595

  11. Theta-alpha EEG phase distributions in the frontal area for dissociation of visual and auditory working memory.

    PubMed

    Akiyama, Masakazu; Tero, Atsushi; Kawasaki, Masahiro; Nishiura, Yasumasa; Yamaguchi, Yoko

    2017-03-07

    Working memory (WM) is known to be associated with synchronization of the theta and alpha bands observed in electroencephalograms (EEGs). Although frontal-posterior global theta synchronization appears in modality-specific WM, local theta synchronization in frontal regions has been found in modality-independent WM. How frontal theta oscillations separately synchronize with task-relevant sensory brain areas remains an open question. Here, we focused on theta-alpha phase relationships in frontal areas using EEG, and then verified their functional roles with mathematical models. EEG data showed that the relationship between theta (6 Hz) and alpha (12 Hz) phases in the frontal areas was about 1:2 during both auditory and visual WM, and that the phase distributions between auditory and visual WM were different. Next, we used the differences in phase distributions to construct FitzHugh-Nagumo type mathematical models. The results replicated the modality-specific branching by orthogonally of the trigonometric functions for theta and alpha oscillations. Furthermore, mathematical and experimental results were consistent with regards to the phase relationships and amplitudes observed in frontal and sensory areas. These results indicate the important role that different phase distributions of theta and alpha oscillations have in modality-specific dissociation in the brain.

  12. Resting posterior versus frontal delta/theta EEG activity is associated with extraversion and the COMT VAL(158)MET polymorphism.

    PubMed

    Wacker, Jan; Gatt, Justine Megan

    2010-07-05

    Recent studies suggest that resting posterior versus frontal EEG delta/theta activity (delta/theta Pz-Fz) is both sensitive to pharmacological manipulations of neural dopamine and associated with the agency facet of extraversion (i.e., a motivational disposition comprising enthusiasm, energy, assertiveness, achievement striving and social dominance). These observations suggest that posterior versus frontal resting EEG delta/theta activity may represent a useful marker for investigating the molecular genetic basis of extraversion. The present study aimed to test the novel hypothesis of an association between delta/theta Pz-Fz and a functional polymorphism of the enzyme catechol-O-methyltransferase (COMT VAL(158)MET) involved in dopamine catabolism. This was conducted in a large EEG data set from the Brain Resource International Database (BRID; resting EEG from N=1093 healthy individuals, 382 of which also genotyped for COMT VAL(158)MET). In summary, we (1) showed for the first time that the VAL allele is associated with increased delta/theta Pz-Fz; (2) replicated the association between extraversion and delta/theta Pz-Fz in a large, heterogeneous sample including both genders; and (3) documented that the VAL allele of the COMT VAL(158)MET is associated with increased extraversion scores, as previously reported for an overlapping BRID sample. This coherent pattern of findings adds further support to the suggestion that the posterior-anterior distribution of resting EEG slow wave activity in the delta/theta range represents a useful tool for probing the dopaminergic basis of extraversion.

  13. Trial-by-trial coupling between EEG and BOLD identifies networks related to alpha and theta EEG power increases during working memory maintenance.

    PubMed

    Scheeringa, René; Petersson, Karl Magnus; Oostenveld, Robert; Norris, David G; Hagoort, Peter; Bastiaansen, Marcel C M

    2009-02-01

    PET and fMRI experiments have previously shown that several brain regions in the frontal and parietal lobe are involved in working memory maintenance. MEG and EEG experiments have shown parametric increases with load for oscillatory activity in posterior alpha and frontal theta power. In the current study we investigated whether the areas found with fMRI can be associated with these alpha and theta effects by measuring simultaneous EEG and fMRI during a modified Sternberg task This allowed us to correlate EEG at the single trial level with the fMRI BOLD signal by forming a regressor based on single trial alpha and theta power estimates. We observed a right posterior, parametric alpha power increase, which was functionally related to decreases in BOLD in the primary visual cortex and in the posterior part of the right middle temporal gyrus. We relate this finding to the inhibition of neuronal activity that may interfere with WM maintenance. An observed parametric increase in frontal theta power was correlated to a decrease in BOLD in regions that together form the default mode network. We did not observe correlations between oscillatory EEG phenomena and BOLD in the traditional WM areas. In conclusion, the study shows that simultaneous EEG-fMRI recordings can be successfully used to identify the emergence of functional networks in the brain during the execution of a cognitive task.

  14. Clozapine augments delta, theta, and right frontal EEG alpha power in schizophrenic patients.

    PubMed

    Maccrimmon, D; Brunet, D; Criollo, M; Galin, H; Lawson, J S

    2012-01-01

    Objective. To explore the Quantitative EEG (QEEG) effects of established clozapine therapy regimes compared to those of previous ineffective antipsychotic regimes among 64 chronic (DSM-IV) schizophrenic patients. Methods. Data from 20 EEG channels referenced to linked ears were collected before and during maintenance clozapine therapy (mean duration 1.4 years). Absolute power was calculated in six frequency bands: delta (0.4-3.6 Hz), theta (4.2-7.8 Hz), alpha (8.2-11.8 Hz), beta1 (12.2-15.8 Hz), beta2 (16.2-19.8 Hz), and beta3 (20.2-23.8 Hz). Results. Clozapine augments power globally in the delta and theta bands, but this effect is more pronounced over frontal areas. Beta3 power was reduced. Alpha showed a frontal increase, more pronounced in the right, coupled with a posterior decrease with no net change in overall power. Conclusion. The demonstration of a significant clozapine-induced alpha topographic shift frontally and to the right is a novel discovery that may serve to encourage further investigations of subcortical structures in attempts to better understand the diverse aetiologies and optimal treatments of the schizophrenias.

  15. Clozapine Augments Delta, Theta, and Right Frontal EEG Alpha Power in Schizophrenic Patients

    PubMed Central

    MacCrimmon, D.; Brunet, D.; Criollo, M.; Galin, H.; Lawson, J. S.

    2012-01-01

    Objective. To explore the Quantitative EEG (QEEG) effects of established clozapine therapy regimes compared to those of previous ineffective antipsychotic regimes among 64 chronic (DSM-IV) schizophrenic patients. Methods. Data from 20 EEG channels referenced to linked ears were collected before and during maintenance clozapine therapy (mean duration 1.4 years). Absolute power was calculated in six frequency bands: delta (0.4–3.6 Hz), theta (4.2–7.8 Hz), alpha (8.2–11.8 Hz), beta1 (12.2–15.8 Hz), beta2 (16.2–19.8 Hz), and beta3 (20.2–23.8 Hz). Results. Clozapine augments power globally in the delta and theta bands, but this effect is more pronounced over frontal areas. Beta3 power was reduced. Alpha showed a frontal increase, more pronounced in the right, coupled with a posterior decrease with no net change in overall power. Conclusion. The demonstration of a significant clozapine-induced alpha topographic shift frontally and to the right is a novel discovery that may serve to encourage further investigations of subcortical structures in attempts to better understand the diverse aetiologies and optimal treatments of the schizophrenias. PMID:23738206

  16. EEG theta and Mu oscillations during perception of human and robot actions.

    PubMed

    Urgen, Burcu A; Plank, Markus; Ishiguro, Hiroshi; Poizner, Howard; Saygin, Ayse P

    2013-01-01

    The perception of others' actions supports important skills such as communication, intention understanding, and empathy. Are mechanisms of action processing in the human brain specifically tuned to process biological agents? Humanoid robots can perform recognizable actions, but can look and move differently from humans, and as such, can be used in experiments to address such questions. Here, we recorded EEG as participants viewed actions performed by three agents. In the Human condition, the agent had biological appearance and motion. The other two conditions featured a state-of-the-art robot in two different appearances: Android, which had biological appearance but mechanical motion, and Robot, which had mechanical appearance and motion. We explored whether sensorimotor mu (8-13 Hz) and frontal theta (4-8 Hz) activity exhibited selectivity for biological entities, in particular for whether the visual appearance and/or the motion of the observed agent was biological. Sensorimotor mu suppression has been linked to the motor simulation aspect of action processing (and the human mirror neuron system, MNS), and frontal theta to semantic and memory-related aspects. For all three agents, action observation induced significant attenuation in the power of mu oscillations, with no difference between agents. Thus, mu suppression, considered an index of MNS activity, does not appear to be selective for biological agents. Observation of the Robot resulted in greater frontal theta activity compared to the Android and the Human, whereas the latter two did not differ from each other. Frontal theta thus appears to be sensitive to visual appearance, suggesting agents that are not sufficiently biological in appearance may result in greater memory processing demands for the observer. Studies combining robotics and neuroscience such as this one can allow us to explore neural basis of action processing on the one hand, and inform the design of social robots on the other.

  17. EEG theta and Mu oscillations during perception of human and robot actions

    PubMed Central

    Urgen, Burcu A.; Plank, Markus; Ishiguro, Hiroshi; Poizner, Howard; Saygin, Ayse P.

    2013-01-01

    The perception of others’ actions supports important skills such as communication, intention understanding, and empathy. Are mechanisms of action processing in the human brain specifically tuned to process biological agents? Humanoid robots can perform recognizable actions, but can look and move differently from humans, and as such, can be used in experiments to address such questions. Here, we recorded EEG as participants viewed actions performed by three agents. In the Human condition, the agent had biological appearance and motion. The other two conditions featured a state-of-the-art robot in two different appearances: Android, which had biological appearance but mechanical motion, and Robot, which had mechanical appearance and motion. We explored whether sensorimotor mu (8–13 Hz) and frontal theta (4–8 Hz) activity exhibited selectivity for biological entities, in particular for whether the visual appearance and/or the motion of the observed agent was biological. Sensorimotor mu suppression has been linked to the motor simulation aspect of action processing (and the human mirror neuron system, MNS), and frontal theta to semantic and memory-related aspects. For all three agents, action observation induced significant attenuation in the power of mu oscillations, with no difference between agents. Thus, mu suppression, considered an index of MNS activity, does not appear to be selective for biological agents. Observation of the Robot resulted in greater frontal theta activity compared to the Android and the Human, whereas the latter two did not differ from each other. Frontal theta thus appears to be sensitive to visual appearance, suggesting agents that are not sufficiently biological in appearance may result in greater memory processing demands for the observer. Studies combining robotics and neuroscience such as this one can allow us to explore neural basis of action processing on the one hand, and inform the design of social robots on the other. PMID

  18. Mathematical cognitive style and arithmetic sign comprehension: a study of EEG alpha and theta activity.

    PubMed

    Earle, J B; Garcia-Dergay, P; Manniello, A; Dowd, C

    1996-01-01

    The localization of arithmetic sign comprehension was investigated using EEG spectral parameters as indicators of cortical engagement. Right-handed male subjects were selected on the basis of scores on the Mathematics Cognitive Style Survey and assigned to 2 groups, a 'left hemisphere oriented (LHO)' (N = 9) and 'right hemisphere oriented (RHO)' (N = 9) group. Subjects were presented with 4 conditions, a motoric baseline condition, two arithmetic fact retrieval tasks employing either a sign operator or verbal operator and a sign comprehension task which required subjects to fill in a missing sign (e.g. 6 ? 4 = 24). Both across subject correlational analysis of EEG alpha 1 asymmetry and performance as well as within subject analysis of condition means indicated a somewhat unique contribution of the right hemisphere to sign comprehension. LHO subjects exhibited greater relative left mid-temporal lobe activation than RHO subjects but less relative left frontal activation (theta band) than RHO subjects during the verbal operator task. It was tentatively concluded that this frontal lobe asymmetry difference was due to a mismatch in strategy preference and coding requirements among RHO subjects.

  19. Indication of increased phase coupling between theta and gamma EEG rhythms associated with the experience of auditory verbal hallucinations.

    PubMed

    Koutsoukos, Elias; Angelopoulos, Elias; Maillis, Antonis; Papadimitriou, George N; Stefanis, Costas

    2013-02-08

    Electroencephalographic oscillations, with different spectral contents, recorded in various brain sites are assumed to play an important role in the information processes underlying cognition as well as the abnormal brain functioning observed in nosological entities that affect neuronal connectivity such as schizophrenia. In the present study we investigated the interaction of EEG rhythms during the experience of auditory verbal hallucinations (AVHs). For this purpose we analyzed data obtained from patients suffering from persistent AVHs, focusing on the mode that the phase of theta oscillations modulate the amplitude of the broad gamma EEG oscillations. Our results indicate increased phase coupling between theta and gamma rhythms observed in the left frontotemporal cortices during AVHs, under eyes closed condition. The average differences of theta-gamma coupling between hallucinatory and resting stages in the left temporal area were found to be statistically significant. These results suggest that a theta-gamma interaction may be involved in the production and experience of AVHs in patients suffering from schizophrenia.

  20. Morning nutrition and executive function processes in preadolescents: gender variations in phasic modulation of frontal eeg theta activity during a go/ no-go task

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Frontal EEG theta activity has been related to executive functions (i.e., goal-directed behavior such as inhibition and flexibility of action). We studied the effects of morning nutritional status on frontal theta-executive function relationships using stimulus-locked responses [event-related increa...

  1. Frontal predominance of a relative increase in sleep delta and theta EEG activity after sleep loss in humans

    NASA Technical Reports Server (NTRS)

    Cajochen, C.; Foy, R.; Dijk, D. J.; Czeisler, C. A. (Principal Investigator)

    1999-01-01

    The effect of sleep deprivation (40 h) on topographic and temporal aspects of electroencephalographic (EEG) activity during sleep was investigated by all night spectral analysis in six young volunteers. The sleep-deprivation-induced increase of EEG power density in the delta and theta frequencies (1-7 Hz) during nonREM sleep, assessed along the antero-posterior axis (midline: Fz, Cz, Pz, Oz), was significantly larger in the more frontal derivations (Fz, Cz) than in the more parietal derivations (Pz, Oz). This frequency-specific frontal predominance was already present in the first 30 min of recovery sleep, and dissipated in the course of the 8-h sleep episode. The data demonstrate that the enhancement of slow wave EEG activity during sleep following extended wakefulness is most pronounced in frontal cortical areas.

  2. Auto power and coherence analysis of delta-theta band EEG during the waking-sleeping transition period.

    PubMed

    Morikawa, T; Hayashi, M; Hori, T

    1997-12-01

    To evaluate the spatio-temporal variation of delta and theta band EEGs during the waking-sleeping transition period, auto power and coherence analyses of scalp EEGs were carried out on 12 male subjects. The 7 auto power and 21 coherence values obtained from the 7 areas were studied every 20 s from 5 min before stage 1 onset to 24 min after stage 1 onset. The consecutive samples of spectra were computed for two frequency bands (delta: 2.5-3.5 Hz; theta: 4.0-7.5 Hz). Auto power started to increase after stage 1 onset and terminated 8.4 min after stage 2 onset. Topograms of each band power changed with progression towards deep sleep from the flat or relatively low voltage pattern without any focus to the frontopolar-parietal pattern or the fronto-parietal dominant pattern. Principal component analysis of the coherence values revealed generalized and localized components in each band. The generalized component was distributed across scalp areas, while the localized component was distributed in frontopolar-frontal areas. The generalized component decreased to the plateau level of non-rapid eye movement (NREM) sleep 5.4 min after stage 2 onset. The localized component started to increase after stage 1 onset and reached the plateau level of NREM sleep 2.4 min after stage 2 onset. These results indicate that the delta-theta band EEG structures of the waking-sleeping transition period may not be uniform across the scalp areas and the hypnagogic period may start after stage 1 onset and continue for 8.4 min after stage 2 onset.

  3. Resting EEG theta activity predicts cognitive performance in attention-deficit hyperactivity disorder.

    PubMed

    Hermens, Daniel F; Soei, Eleonore X C; Clarke, Simon D; Kohn, Michael R; Gordon, Evian; Williams, Leanne M

    2005-04-01

    Quantitative electroencephalography has contributed significantly to elucidating the neurobiologic mechanisms of attention-deficit hyperactivity disorder. The most consistent and robust electroencephalographic disturbance in attention-deficit hyperactivity disorder has been abnormally increased theta band during resting conditions. Separate research using attention-demanding tests has elucidated cognitive disturbances that differentiate attention-deficit hyperactivity disorder. This study attempts to integrate electroencephalographic and neuropsychological indices to determine whether cognitive performance is specifically related to increased theta. Theta activity was recorded during a resting condition for 46 children/adolescents with attention-deficit hyperactivity disorder and their sex- and age-matched control subjects. Accuracy and reaction time during an auditory oddball and a visual continuous performance test were then recorded. Compared with control subjects, the attention-deficit hyperactivity disorder group manifested significantly increased (primarily left) frontal theta. Furthermore, the attention-deficit hyperactivity disorder group scored significantly delayed reaction time and decreased accuracy in both tasks. Correlation analysis revealed a significant relationship between frontal (primarily left) theta and oddball accuracy for the attention-deficit hyperactivity disorder group compared with a significant relationship between posterior (primarily right) theta and reaction time in the continuous performance test for the control group. These results indicate that spatial neurophysiologic deficits in attention-deficit hyperactivity disorder may be related to disturbances in signal detection. This observation has important implications for the role of trait-like biologic deficits in attention-deficit hyperactivity disorder predicting performance in information processing.

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

    PubMed

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

    2016-07-01

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

  5. Fluctuating Inhibitory Inputs Promote Reliable Spiking at Theta Frequencies in Hippocampal Interneurons

    PubMed Central

    Sritharan, Duluxan; Skinner, Frances K.

    2012-01-01

    Theta-frequency (4–12 Hz) rhythms in the hippocampus play important roles in learning and memory. CA1 interneurons located at the stratum lacunosum-moleculare and radiatum junction (LM/RAD) are thought to contribute to hippocampal theta population activities by rhythmically pacing pyramidal cells with inhibitory postsynaptic potentials. This implies that LM/RAD cells need to fire reliably at theta frequencies in vivo. To determine whether this could occur, we use biophysically based LM/RAD model cells and apply different cholinergic and synaptic inputs to simulate in vivo-like network environments. We assess spike reliabilities and spiking frequencies, identifying biophysical properties and network conditions that best promote reliable theta spiking. We find that synaptic background activities that feature large inhibitory, but not excitatory, fluctuations are essential. This suggests that strong inhibitory input to these cells is vital for them to be able to contribute to population theta activities. Furthermore, we find that Type I-like oscillator models produced by augmented persistent sodium currents (INaP) or diminished A-type potassium currents (IA) enhance reliable spiking at lower theta frequencies. These Type I-like models are also the most responsive to large inhibitory fluctuations and can fire more reliably under such conditions. In previous work, we showed that INaP and IA are largely responsible for establishing LM/RAD cells’ subthreshold activities. Taken together with this study, we see that while both these currents are important for subthreshold theta fluctuations and reliable theta spiking, they contribute in different ways – INaP to reliable theta spiking and subthreshold activity generation, and IA to subthreshold activities at theta frequencies. This suggests that linking subthreshold and suprathreshold activities should be done with consideration of both in vivo contexts and biophysical specifics. PMID:22654751

  6. Interhemispheric Asymmetries and Theta Activity in the Rostral Anterior Cingulate Cortex as EEG Signature of HIV-Related Depression: Gender Matters.

    PubMed

    Kremer, Heidemarie; Lutz, Franz P C; McIntosh, Roger C; Dévieux, Jessy G; Ironson, Gail

    2016-04-01

    Resting EEGs of 40 people living with HIV (PLWH) on long-term antiretroviral treatment were examined for z-scored deviations from a healthy control (normative database) to examine the main and interaction effects of depression and gender. Regions of interest were frontal (alpha) and central (all bands) for interhemispheric asymmetries in quantitative EEGs and theta in the rostral anterior cingulate cortex (rACC) in low-resolution electromagnetic tomography (LORETA). Z-scored normed deviations of depressed PLWH, compared with nondepressed, showed right-dominant interhemispheric asymmetries in all regions. However, after adjusting for multiple testing, significance remained only central for theta, alpha, and beta. Reversed (left-dominant) frontal alpha asymmetry is a potential EEG marker of depression in the HIV negative population that was not reversed in depressive PLWH; however, corresponding with extant literature, gender had an effect on the size of frontal alpha asymmetry. The LORETA analysis revealed a trending interactional effect of depression and gender on theta activity in the rACC in Brodmann area 32. We found that compared to men, women had greater right-dominant frontal alpha-asymmetry and elevated theta activity in voxels of the rACC, which may indicate less likelihood of depression and a higher likelihood of response to antidepressants. In conclusion, subtle EEG deviations, such as right-dominant central theta, alpha, and beta asymmetries and theta activity in the rACC may mark HIV-related depressive symptoms and may predict the likelihood of response to antidepressants but gender effects need to be taken into account. Although this study introduced the use of LORETA to examine the neurophysiological correlates of negative affect in PLWH, further research is needed to assess the utility of this tool in diagnostics and treatment monitoring of depression in PLWH.

  7. Frontal EEG theta/beta ratio as an electrophysiological marker for attentional control and its test-retest reliability.

    PubMed

    Angelidis, Angelos; van der Does, Willem; Schakel, Lemmy; Putman, Peter

    2016-12-01

    A robust finding is that resting-state frontal theta/beta ratio (TBR), a spontaneous electroencephalographic (EEG) frequency band parameter, is increased in attention-deficit/hyperactivity disorder. Accumulating evidence suggests that TBR might also provide an objective marker of executive cognitive control (and more specifically attentional control; AC) in healthy adults. The present study aimed to further investigate this conception by assessing EEG frequency band power and AC twice (with a one-week interval) in 41 young female adults. In line with our predictions, the negative association between TBR and trait AC, as measured with an often used self-report measure, was replicated. Results also demonstrated that test-retest reliability of resting-state frontal TBR was very good (r=.93) and, moreover, TBR measured at the first session predicted AC during the second session (r=-.44). These consistent results further reinforce the notion that frontal TBR could be used as a reliable biomarker for prefrontally-mediated executive AC.

  8. The increase in theta/beta ratio on resting-state EEG in boys with attention-deficit/hyperactivity disorder is mediated by slow alpha peak frequency.

    PubMed

    Lansbergen, Marieke M; Arns, Martijn; van Dongen-Boomsma, Martine; Spronk, Desirée; Buitelaar, Jan K

    2011-01-15

    Attention-deficit/hyperactivity disorder (ADHD) was found to be characterized by a deviant pattern of electrocortical activity during resting state, particularly increased theta and decreased beta activity. The first objective of the present study is to confirm whether individuals with slow alpha peak frequency contribute to the finding of increased theta activity in ADHD. The second objective is to explore the relation between resting-state brain oscillations and specific cognitive functions. From 49 boys with ADHD and 49 healthy control boys, resting-state EEG during eyes open and eyes closed was recorded, and a variety of cognitive tasks were administered. Theta and beta power and theta/beta ratio were calculated using both fixed frequency bands and individualized frequency bands. As expected, theta/beta ratio, calculated using fixed frequency bands, was significantly higher in ADHD children than control children. However, this group effect was not significant when theta/beta ratio was assessed using individualized frequency bands. No consistent relation was found between resting-state brain oscillations and cognition. The present results suggest that previous findings of increased theta/beta ratio in ADHD may reflect individuals with slow alpha peak frequencies in addition to individuals with true increased theta activity. Therefore, the often reported theta/beta ratio in ADHD can be considered a non-specific measure combining several distinct neurophysiological subgroups such as frontal theta and slowed alpha peak frequencies. Future research should elucidate the functional role of resting-state brain oscillations by investigating neurophysiological subgroups, which may have a clearer relation to cognitive functions than single frequency bands.

  9. Anodal transcranial direct current stimulation (tDCS) increases frontal-midline theta activity in the human EEG: a preliminary investigation of non-invasive stimulation.

    PubMed

    Miller, Joe; Berger, Barbara; Sauseng, Paul

    2015-02-19

    Rhythmical brain activity in the range between four and eight Hz acquired over frontal-midline EEG recording sites - so called frontal-midline theta activity - is regarded as one of the most prominent neural signatures of sustained attention. It is reported to parametrically increase with cognitive load and is thought to be generated in medial prefrontal cortex. Here we explored the possibility of using anodal transcranial direct current stimulation over frontal sites to enhance frontal-midline theta activity and to increase sustained attention performance. We used a small preliminary sample to test a novel direct current stimulation electrode configuration by which we were able to significantly increase frontal-midline theta amplitude in a resting condition after the end of the stimulation period. Using standardised low resolution electromagnetic tomography analysis the effect in the surface EEG was localised to right prefrontal and left medial prefrontal brain areas. Transcranial direct current stimulation did, however, not have any impact on behavioural performance during a sustained attention task. This most likely was due to a very fast washout of the stimulation's after effect on theta activity. Although these are only preliminary results from a rather small sample, this study demonstrates that transcranial direct current stimulation can be used to rather selectively enhance frontal-midline theta amplitude.

  10. EEG theta/beta ratio as a potential biomarker for attentional control and resilience against deleterious effects of stress on attention.

    PubMed

    Putman, Peter; Verkuil, Bart; Arias-Garcia, Elsa; Pantazi, Ioanna; van Schie, Charlotte

    2014-06-01

    Anxious stress compromises cognitive executive performance. This occurs, for instance, in cognitive performance anxiety (CPA), in which anxiety about one's cognitive performance causes that performance to actually deteriorate (e.g., test anxiety). This is thought to result from a prefrontal cortically (PFC) mediated failure of top-down attentional control over stress-induced automatic processing of threat-related information. In addition, stress-induced increased catecholamine influx into the PFC may directly compromise attentional function. Previous research has suggested that the ratio between resting state electroencephalographic (EEG) low- and high-frequency power (the theta/beta ratio) is related to trait attentional control, which might moderate these effects of stress on attentional function. The goals of the present study were to test the novel prediction that theta/beta ratio moderates the deleterious effects of CPA-like anxious stress on state attentional control and to replicate a previous finding that the theta/beta ratio is related to self-reported trait attentional control. After recording of baseline frontal EEG signals, 77 participants performed a stress induction or a control procedure. Trait attentional control was assessed with the Attentional Control Scale, whereas stress-induced changes in attentional control and anxiety were measured with self-report visual analogue scales. The hypothesized moderating influence of theta/beta ratio on the effects of stress on state attentional control was confirmed. Theta/beta ratio explained 28% of the variance in stress-induced deterioration of self-reported attentional control. The negative relationship between theta/beta ratio and trait attentional control was replicated (r = -.33). The theta/beta ratio reflects, likely prefrontally mediated, attentional control, and should be a useful biomarker for the study of CPA and other anxiety-cognition interactions.

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

    PubMed

    Klimesch, W; Doppelmayr, M; Pachinger, T; Ripper, B

    1997-11-28

    The EEG was recorded while subjects judged whether sequentially presented feature-concept pairs are semantically congruent. Later and without prior warning they had to perform a semantic and episodic memory task. The results show that the upper alpha band is most sensitive to the encoding and processing of semantic information. It is only the upper alpha band that distinguishes between good and bad semantic memory performers and that shows significant correlations with semantic memory performance during that time period, semantic processing actually takes place. Even when the influence of episodic memory was removed by partial correlations, a reliable association between upper alpha desynchronization and semantic memory was observed.

  12. Quantitative EEG in Children and Adults With Attention Deficit Hyperactivity Disorder: Comparison of Absolute and Relative Power Spectra and Theta/Beta Ratio.

    PubMed

    Markovska-Simoska, Silvana; Pop-Jordanova, Nada

    2017-01-01

    In recent decades, resting state electroencephalographic (EEG) measures have been widely used to document underlying neurophysiological dysfunction in attention deficit hyperactivity disorder (ADHD). Although most EEG studies focus on children, there is a growing interest in adults with ADHD too. The aim of this study was to objectively assess and compare the absolute and relative EEG power as well as the theta/beta ratio in children and adults with ADHD. The evaluated sample comprised 30 male children and 30 male adults with ADHD diagnosed according to DSM-IV criteria. They were compared with 30 boys and 30 male adults matched by age. The mean age (±SD) of the children's group was 9 (±2.44) years and the adult group 35.8 (±8.65) years. EEG was recorded during an eyes-open condition. Spectral analysis of absolute (μV(2)) and relative power (%) was carried out for 4 frequency bands: delta (2-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-21 Hz). The findings obtained for ADHD children are increased absolute power of slow waves (theta and delta), whereas adults exhibited no differences compared with normal subjects. For the relative power spectra there were no differences between the ADHD and control groups. Across groups, the children showed greater relative power than the adults in the delta and theta bands, but for the higher frequency bands (alpha and beta) the adults showed more relative power than children. Only ADHD children showed greater theta/beta ratio compared to the normal group. Classification analysis showed that ADHD children could be differentiated from the control group by the absolute theta values and theta/beta ratio at Cz, but this was not the case with ADHD adults. The question that should be further explored is if these differences are mainly due to maturation processes or if there is a core difference in cortical arousal between ADHD children and adults.

  13. EEG Theta Dynamics within Frontal and Parietal Cortices for Error Processing during Reaching Movements in a Prism Adaptation Study Altering Visuo-Motor Predictive Planning.

    PubMed

    Arrighi, Pieranna; Bonfiglio, Luca; Minichilli, Fabrizio; Cantore, Nicoletta; Carboncini, Maria Chiara; Piccotti, Emily; Rossi, Bruno; Andre, Paolo

    2016-01-01

    Modulation of frontal midline theta (fmθ) is observed during error commission, but little is known about the role of theta oscillations in correcting motor behaviours. We investigate EEG activity of healthy partipants executing a reaching task under variable degrees of prism-induced visuo-motor distortion and visual occlusion of the initial arm trajectory. This task introduces directional errors of different magnitudes. The discrepancy between predicted and actual movement directions (i.e. the error), at the time when visual feedback (hand appearance) became available, elicits a signal that triggers on-line movement correction. Analysis were performed on 25 EEG channels. For each participant, the median value of the angular error of all reaching trials was used to partition the EEG epochs into high- and low-error conditions. We computed event-related spectral perturbations (ERSP) time-locked either to visual feedback or to the onset of movement correction. ERSP time-locked to the onset of visual feedback showed that fmθ increased in the high- but not in the low-error condition with an approximate time lag of 200 ms. Moreover, when single epochs were sorted by the degree of motor error, fmθ started to increase when a certain level of error was exceeded and, then, scaled with error magnitude. When ERSP were time-locked to the onset of movement correction, the fmθ increase anticipated this event with an approximate time lead of 50 ms. During successive trials, an error reduction was observed which was associated with indices of adaptations (i.e., aftereffects) suggesting the need to explore if theta oscillations may facilitate learning. To our knowledge this is the first study where the EEG signal recorded during reaching movements was time-locked to the onset of the error visual feedback. This allowed us to conclude that theta oscillations putatively generated by anterior cingulate cortex activation are implicated in error processing in semi-naturalistic motor

  14. Increased Prevalence of Intermittent Rhythmic Delta or Theta Activity (IRDA/IRTA) in the Electroencephalograms (EEGs) of Patients with Borderline Personality Disorder

    PubMed Central

    Tebartz van Elst, Ludger; Fleck, Max; Bartels, Susanne; Altenmüller, Dirk-Matthias; Riedel, Andreas; Bubl, Emanuel; Matthies, Swantje; Feige, Bernd; Perlov, Evgeniy; Endres, Dominique

    2016-01-01

    Introduction: An increased prevalence of pathological electroencephalography (EEG) signals has been reported in patients with borderline personality disorder (BPD). In an elaborative case description of such a patient with intermittent rhythmic delta and theta activity (IRDA/IRTA), the BPD symptoms where linked to the frequency of the IRDAs/IRTAs and vanished with the IRDAs/IRTAs following anticonvulsive therapy. This observation raised a question regarding the prevalence of such EEG abnormalities in BPD patients. The aim of this retrospective study was to identify the frequency of EEG abnormalities in a carefully analyzed psychiatric collective. Following earlier reports, we hypothesized an increased prevalence of EEG abnormalities in BPD patients. Participants and Methods: We recruited 96 consecutive patients with BPD from the archive of a university clinic for psychiatry and psychotherapy, and compared the prevalence of EEG abnormalities to those of 76 healthy controls subjects. The EEGs were rated by three different blinded clinicians, including a consultant specializing in epilepsy from the local epilepsy center. Results: We found a significant increase in the prevalence of IRDAs and IRTAs in BPD patients (14.6%) compared to the control subjects (3.9%; p = 0.020). Discussion: In this blinded retrospective case-control study, we were able to confirm an increased prevalence of pathological EEG findings (IRDAs/IRTAs only) in BPD patients. The major limitation of this study is that the control group was not matched on age and gender. Therefore, the results should be regarded as preliminary findings of an open uncontrolled, retrospective study. Future research performing prospective, controlled studies is needed to verify our findings and answer the question of whether such EEG findings might predict a positive response to anticonvulsive pharmacological treatment. PMID:26941624

  15. Successful memory encoding is associated with increased cross-frequency coupling between frontal theta and posterior gamma oscillations in human scalp-recorded EEG.

    PubMed

    Friese, Uwe; Köster, Moritz; Hassler, Uwe; Martens, Ulla; Trujillo-Barreto, Nelson; Gruber, Thomas

    2013-02-01

    Although previous studies have established that successful memory encoding is associated with increased synchronization of theta-band and gamma-band oscillations, it is unclear if there is a functional relationship between oscillations in these frequency bands. Using scalp-recorded EEG in healthy human participants, we demonstrate that cross-frequency coupling between frontal theta phase and posterior gamma power is enhanced during the encoding of visual stimuli which participants later on remember versus items which participants subsequently forget ("subsequent memory effect," SME). Conventional wavelet analyses and source localizations revealed SMEs in spectral power of theta-, alpha-, and gamma-band. Successful compared to unsuccessful encoding was reflected in increased theta-band activity in right frontal cortex as well as increased gamma-band activity in parietal-occipital regions. Moreover, decreased alpha-band activity in prefrontal and occipital cortex was also related to successful encoding. Overall, these findings support the idea that during the formation of new memories frontal cortex regions interact with cortical representations in posterior areas.

  16. Hemifield-dependent N1 and event-related theta/delta oscillations: An unbiased comparison of surface Laplacian and common EEG reference choices

    PubMed Central

    Kayser, Jürgen; Tenke, Craig E.

    2015-01-01

    Surface Laplacian methodology has been used to reduce the impact of volume conduction and arbitrary choice of EEG recording reference for the analysis of surface potentials. However, the empirical implications of employing these different transformations to the same EEG data remain obscure. This study directly compared the statistical effects of four commonly-used (nose, linked mastoids, average) or recommended (reference electrode standardization technique [REST]) references and their spherical spline current source density (CSD) transformation for a large data set stemming from a well-understood experimental manipulation. ERPs (72 sites) recorded from 130 individuals during a visual half-field paradigm with highly-controlled emotional stimuli were characterized by mid-parietooccipital N1 (125 ms peak latency) and event-related synchronization (ERS) of theta/delta (160 ms), which were most robust over the contralateral hemisphere. All five data transformations were rescaled to the same covariance and submitted to a single temporal or time-frequency PCA (Varimax) to yield simplified estimates of N1 or theta/delta ERS. Unbiased nonparametric permutation tests revealed that these hemifield-dependent asymmetries were by far most focal and prominent for CSD data, despite all transformations showing maximum effects at mid-parietooccipital sites. Employing smaller subsamples (signal-to-noise) or window-based ERP/ERS amplitudes did not affect these comparisons. Furthermore, correlations between N1 and theta/delta ERS at these sites were strongest for CSD and weakest for nose-referenced data. Contrary to the common notion that the spatial high pass filter properties of a surface Laplacian reduce important contributions of neuronal generators to the EEG signal, the present findings demonstrate that instead volume conduction inherent in surface potentials weakens the representation of neuronal activation patterns at scalp that directly reflect regional brain activity. PMID

  17. EEG Theta Dynamics within Frontal and Parietal Cortices for Error Processing during Reaching Movements in a Prism Adaptation Study Altering Visuo-Motor Predictive Planning

    PubMed Central

    Bonfiglio, Luca; Minichilli, Fabrizio; Cantore, Nicoletta; Carboncini, Maria Chiara; Piccotti, Emily; Rossi, Bruno

    2016-01-01

    Modulation of frontal midline theta (fmθ) is observed during error commission, but little is known about the role of theta oscillations in correcting motor behaviours. We investigate EEG activity of healthy partipants executing a reaching task under variable degrees of prism-induced visuo-motor distortion and visual occlusion of the initial arm trajectory. This task introduces directional errors of different magnitudes. The discrepancy between predicted and actual movement directions (i.e. the error), at the time when visual feedback (hand appearance) became available, elicits a signal that triggers on-line movement correction. Analysis were performed on 25 EEG channels. For each participant, the median value of the angular error of all reaching trials was used to partition the EEG epochs into high- and low-error conditions. We computed event-related spectral perturbations (ERSP) time-locked either to visual feedback or to the onset of movement correction. ERSP time-locked to the onset of visual feedback showed that fmθ increased in the high- but not in the low-error condition with an approximate time lag of 200 ms. Moreover, when single epochs were sorted by the degree of motor error, fmθ started to increase when a certain level of error was exceeded and, then, scaled with error magnitude. When ERSP were time-locked to the onset of movement correction, the fmθ increase anticipated this event with an approximate time lead of 50 ms. During successive trials, an error reduction was observed which was associated with indices of adaptations (i.e., aftereffects) suggesting the need to explore if theta oscillations may facilitate learning. To our knowledge this is the first study where the EEG signal recorded during reaching movements was time-locked to the onset of the error visual feedback. This allowed us to conclude that theta oscillations putatively generated by anterior cingulate cortex activation are implicated in error processing in semi-naturalistic motor

  18. Intermittent Theta Slowings in Contralateral Side of Weakness after Sleep Deprivation on Spot EEG in Sporadic Hemiplegic Migraine

    PubMed Central

    Lee, Chan-Hyuk; Seo, Man-Wook; Shin, Byoung-Soo; Yang, Tae-Ho; Shin, Hyun-June; Ryu, Han Uk

    2016-01-01

    Hemiplegic migraine (HM) is an uncommon type of migraine which is classified into sporadic and familial subtype. The noticed electroencephalogram (EEG) findings during HM attack are diffuse slowing contralateral to the weakened limb, but are usually normal in asymptomatic states. A 52-year-old woman who suffered from headache accompanying right arm weakness and aphasic symptoms admitted to our hospital. She underwent total five times of EEG including 2 times before admission. Only the last EEG exam after 24 hours of sleep deprivation (SD) showed intermittent slowing and higher amplitude of positive occipital sharp transients (POSTs) on the left parieto-occipital area. Here, we report a case with HM who revealed abnormal EEG findings after SD, which was not observed in the routine EEG study without SD. PMID:28101483

  19. EEG patterns in theta and gamma frequency range and their probable relation to human voluntary movement organization.

    PubMed

    Popivanov, D; Mineva, A; Krekule, I

    1999-05-21

    In experiments with EEG accompanying continuous slow goal-directed voluntary movements we found abrupt short-term transients (STs) of the coefficients of EEG time-varying autoregressive (TVAR) model. The onset of STs indicated (i) a positive EEG wave related to an increase of 3-7 Hz oscillations in time period before the movement start, (ii) synchronization of 35-40 Hz prior to movement start and during the movement when the target is nearly reached. Both these phenomena are expressed predominantly over supplementary motor area, premotor and parietal cortices. These patterns were detected after averaging of EEG segments synchronized to the abrupt changes of the TVAR coefficients computed in the time course of EEG single records. The results are discussed regarding the cognitive aspect of organization of goal-directed movements.

  20. Theta and high-beta networks for feedback processing: a simultaneous EEG-fMRI study in healthy male subjects.

    PubMed

    Andreou, C; Frielinghaus, H; Rauh, J; Mußmann, M; Vauth, S; Braun, P; Leicht, G; Mulert, C

    2017-01-31

    The reward system is important in assessing outcomes to guide behavior. To achieve these purposes, its core components interact with several brain areas involved in cognitive and emotional processing. A key mechanism suggested to subserve these interactions is oscillatory activity, with a prominent role of theta and high-beta oscillations. The present study used single-trial coupling of simultaneously recorded electroencephalography and functional magnetic resonance imaging data to investigate networks associated with oscillatory responses to feedback during a two-choice gambling task in healthy male participants (n=19). Differential associations of theta and high-beta oscillations with non-overlapping brain networks were observed: Increase of high-beta power in response to positive feedback was associated with activations in a largely subcortical network encompassing core areas of the reward network. In contrast, theta-band power increase upon loss was associated with activations in a frontoparietal network that included the anterior cingulate cortex. Trait impulsivity correlated significantly with activations in areas of the theta-associated network. Our results suggest that positive and negative feedback is processed by separate brain networks associated with different cognitive functions. Communication within these networks is mediated by oscillations of different frequency, possibly reflecting different modes of dopaminergic signaling.

  1. Background rhythm frequency and theta power of quantitative EEG analysis: predictive biomarkers for cognitive impairment post-cerebral infarcts.

    PubMed

    Song, Yang; Zang, Da-Wei; Jin, Yan-Yu; Wang, Zhi-Jun; Ni, Hong-Yan; Yin, Jian-Zhong; Ji, Dong-Xu

    2015-04-01

    In clinical settings, cerebral infarct is a common disease of older adults, which usually increases the risk of cognitive impairment. This study aims to assess the quantitative electroencephalography (qEEG) as a predictive biomarker for the development of cognitive impairment, post-cerebral infarcts, in subjects from the Department of Neurology. They underwent biennial EEG recording. Cerebral infarct subjects, with follow-up cognitive evaluation, were analyzed for qEEG measures of background rhythm frequency (BRF) and relative δ, θ, α, and β band power. The relationship between cognitive impairment and qEEG, and other possible predictors, was assessed by Cox regression. The results showed that the risk hazard of developing cognitive impairment was 14 times higher for those with low BRF than for those with high BRF (P < .001). Hazard ratio (HR) was also significant for more than median θ band power (HR = 5, P = .002) compared with less than median θ band power. The HRs for δ, α, and β bands were equal to the baseline demographic, and clinical characteristics were not significantly different. In conclusion, qEEG measures of BRF, and relative power in θ band, are potential predictive biomarkers for cognitive impairment in patients with cerebral infarcts. These biomarkers might be valuable in early prediction of cognitive impairment in patients with cerebral infarcts.

  2. EEG

    MedlinePlus

    Chernecky CC, Berger BJ. Electroencephalography (EEG) - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. Philadelphia, PA: Elsevier Saunders; 2013: ...

  3. [The theta rhythm of the infant EEG and the development of the mechanisms of voluntary control of attention in the 2nd half of the first year of life].

    PubMed

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

    1998-01-01

    The neurophysiological basis of attention control was studied in infants at the second half-year of life, i.e. in the period when the capability for voluntary control over behavior fundamentally improves. EEG was recorded in 60 infants aed 8-11 months in three experimental conditions: 1) attention to an object in the visual field (externally controlled attention, or the baseline state), 2) anticipation of a person in the peek-a-boo game (internally controlled attention), 3) attention to the reappeared person in the peek-a-boo game (control condition). The spectral analysis of the EEG data revealed a sharp increase in the EEG theta (3.6-6.0 Hz) during internally controlled attention as compared to the baseline and control conditions. The theta1 (3.6-4.8 Hz) increase was maximal in the frontal derivations. The reactivity of the frontal theta1 during internally controlled attention discriminated infants with different abilities to maintain this type of attention. The reactivity of the theta2 (5.2-6.0 Hz) was maximal in the right temporal derivation (T6) and did not depend on stability of the anticipatory attention. The findings point to different functional significance of the theta1 and theta2 rhythms in infants. It is suggested that synchronization of the frontal theta1 rhythm in infants reflects the activity of the anterior attention system which realizes the executive attention control. The ability to maintain anticipatory attention increased with age, whereas the frontal theta1 synchronization decreased and totally disappeared at the age of 11 months. At the age of 8 months there was a positive correlation between the frontal theta1 synchronization and behavioral index of stability of the internally controlled attention. On the contrary, this correlation was negative at the age of 9 and 10 months. It is suggested that the age-dependent dynamics of the relationship between the frontal theta1 reactivity and attention reflects a leap in maturation of the anterior

  4. Fronto-central theta oscillations are related to oscillations in saccadic response times (SRT): an EEG and behavioral data analysis.

    PubMed

    Diederich, Adele; Schomburg, Annette; van Vugt, Marieke

    2014-01-01

    The phase reset hypothesis states that the phase of an ongoing neural oscillation, reflecting periodic fluctuations in neural activity between states of high and low excitability, can be shifted by the occurrence of a sensory stimulus so that the phase value become highly constant across trials (Schroeder et al., 2008). From EEG/MEG studies it has been hypothesized that coupled oscillatory activity in primary sensory cortices regulates multi sensory processing (Senkowski et al. 2008). We follow up on a study in which evidence of phase reset was found using a purely behavioral paradigm by including also EEG measures. In this paradigm, presentation of an auditory accessory stimulus was followed by a visual target with a stimulus-onset asynchrony (SOA) across a range from 0 to 404 ms in steps of 4 ms. This fine-grained stimulus presentation allowed us to do a spectral analysis on the mean SRT as a function of the SOA, which revealed distinct peak spectral components within a frequency range of 6 to 11 Hz with a modus of 7 Hz. The EEG analysis showed that the auditory stimulus caused a phase reset in 7-Hz brain oscillations in a widespread set of channels. Moreover, there was a significant difference in the average phase at which the visual target stimulus appeared between slow and fast SRT trials. This effect was evident in three different analyses, and occurred primarily in frontal and central electrodes.

  5. Medial septal GABAergic projection neurons promote object exploration behavior and type 2 theta rhythm

    PubMed Central

    Gangadharan, Gireesh; Shin, Jonghan; Kim, Seong-Wook; Kim, Angela; Paydar, Afshin; Kim, Duk-Soo; Miyazaki, Taisuke; Watanabe, Masahiko; Yanagawa, Yuchio; Kim, Jinhyun; Kim, Yeon-Soo; Kim, Daesoo; Shin, Hee-Sup

    2016-01-01

    Exploratory drive is one of the most fundamental emotions, of all organisms, that are evoked by novelty stimulation. Exploratory behavior plays a fundamental role in motivation, learning, and well-being of organisms. Diverse exploratory behaviors have been described, although their heterogeneity is not certain because of the lack of solid experimental evidence for their distinction. Here we present results demonstrating that different neural mechanisms underlie different exploratory behaviors. Localized Cav3.1 knockdown in the medial septum (MS) selectively enhanced object exploration, whereas the null mutant (KO) mice showed enhanced-object exploration as well as open-field exploration. In MS knockdown mice, only type 2 hippocampal theta rhythm was enhanced, whereas both type 1 and type 2 theta rhythm were enhanced in KO mice. This selective effect was accompanied by markedly increased excitability of septo-hippocampal GABAergic projection neurons in the MS lacking T-type Ca2+ channels. Furthermore, optogenetic activation of the septo-hippocampal GABAergic pathway in WT mice also selectively enhanced object exploration behavior and type 2 theta rhythm, whereas inhibition of the same pathway decreased the behavior and the rhythm. These findings define object exploration distinguished from open-field exploration and reveal a critical role of T-type Ca2+ channels in the medial septal GABAergic projection neurons in this behavior. PMID:27208094

  6. Morning nutrition and executive function processes in preadolescents: modulation of frontal event-related theta, beta and gamma EEG oscillations during a go/ no-go task

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Executive functions (i.e., goal-directed behavior such as inhibition and flexibility of action) have been linked to frontal brain regions and to covariations in oscillatory brain activity, e.g., theta and gamma activity. We studied the effects of morning nutritional status on executive function rel...

  7. Hypnotic induction is followed by state-like changes in the organization of EEG functional connectivity in the theta and beta frequency bands in high-hypnotically susceptible individuals.

    PubMed

    Jamieson, Graham A; Burgess, Adrian P

    2014-01-01

    Altered state theories of hypnosis posit that a qualitatively distinct state of mental processing, which emerges in those with high hypnotic susceptibility following a hypnotic induction, enables the generation of anomalous experiences in response to specific hypnotic suggestions. If so then such a state should be observable as a discrete pattern of changes to functional connectivity (shared information) between brain regions following a hypnotic induction in high but not low hypnotically susceptible participants. Twenty-eight channel EEG was recorded from 12 high susceptible (highs) and 11 low susceptible (lows) participants with their eyes closed prior to and following a standard hypnotic induction. The EEG was used to provide a measure of functional connectivity using both coherence (COH) and the imaginary component of coherence (iCOH), which is insensitive to the effects of volume conduction. COH and iCOH were calculated between all electrode pairs for the frequency bands: delta (0.1-3.9 Hz), theta (4-7.9 Hz) alpha (8-12.9 Hz), beta1 (13-19.9 Hz), beta2 (20-29.9 Hz) and gamma (30-45 Hz). The results showed that there was an increase in theta iCOH from the pre-hypnosis to hypnosis condition in highs but not lows with a large proportion of significant links being focused on a central-parietal hub. There was also a decrease in beta1 iCOH from the pre-hypnosis to hypnosis condition with a focus on a fronto-central and an occipital hub that was greater in high compared to low susceptibles. There were no significant differences for COH or for spectral band amplitude in any frequency band. The results are interpreted as indicating that the hypnotic induction elicited a qualitative change in the organization of specific control systems within the brain for high as compared to low susceptible participants. This change in the functional organization of neural networks is a plausible indicator of the much theorized "hypnotic-state."

  8. Hypnotic induction is followed by state-like changes in the organization of EEG functional connectivity in the theta and beta frequency bands in high-hypnotically susceptible individuals

    PubMed Central

    Jamieson, Graham A.; Burgess, Adrian P.

    2014-01-01

    Altered state theories of hypnosis posit that a qualitatively distinct state of mental processing, which emerges in those with high hypnotic susceptibility following a hypnotic induction, enables the generation of anomalous experiences in response to specific hypnotic suggestions. If so then such a state should be observable as a discrete pattern of changes to functional connectivity (shared information) between brain regions following a hypnotic induction in high but not low hypnotically susceptible participants. Twenty-eight channel EEG was recorded from 12 high susceptible (highs) and 11 low susceptible (lows) participants with their eyes closed prior to and following a standard hypnotic induction. The EEG was used to provide a measure of functional connectivity using both coherence (COH) and the imaginary component of coherence (iCOH), which is insensitive to the effects of volume conduction. COH and iCOH were calculated between all electrode pairs for the frequency bands: delta (0.1–3.9 Hz), theta (4–7.9 Hz) alpha (8–12.9 Hz), beta1 (13–19.9 Hz), beta2 (20–29.9 Hz) and gamma (30–45 Hz). The results showed that there was an increase in theta iCOH from the pre-hypnosis to hypnosis condition in highs but not lows with a large proportion of significant links being focused on a central-parietal hub. There was also a decrease in beta1 iCOH from the pre-hypnosis to hypnosis condition with a focus on a fronto-central and an occipital hub that was greater in high compared to low susceptibles. There were no significant differences for COH or for spectral band amplitude in any frequency band. The results are interpreted as indicating that the hypnotic induction elicited a qualitative change in the organization of specific control systems within the brain for high as compared to low susceptible participants. This change in the functional organization of neural networks is a plausible indicator of the much theorized “hypnotic-state.” PMID:25104928

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

    ERIC Educational Resources Information Center

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

    1999-01-01

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

  10. Frontal theta overrides pavlovian learning biases.

    PubMed

    Cavanagh, James F; Eisenberg, Ian; Guitart-Masip, Marc; Huys, Quentin; Frank, Michael J

    2013-05-08

    Pavlovian biases influence learning and decision making by intricately coupling reward seeking with action invigoration and punishment avoidance with action suppression. This bias is not always adaptive-it can often interfere with instrumental requirements. The prefrontal cortex is thought to help resolve such conflict between motivational systems, but the nature of this control process remains unknown. EEG recordings of midfrontal theta band power are sensitive to conflict and predictive of adaptive control over behavior, but it is not clear whether this signal reflects control over conflict between motivational systems. Here we used a task that orthogonalized action requirements and outcome valence while recording concurrent EEG in human participants. By applying a computational model of task performance, we derived parameters reflective of the latent influence of Pavlovian bias and how it was modulated by midfrontal theta power during motivational conflict. Between subjects, those who performed better under Pavlovian conflict exhibited higher midfrontal theta power. Within subjects, trial-to-trial variance in theta power was predictive of ability to overcome the influence of the Pavlovian bias, and this effect was most pronounced in subjects with higher midfrontal theta to conflict. These findings demonstrate that midfrontal theta is not only a sensitive index of prefrontal control, but it can also reflect the application of top-down control over instrumental processes.

  11. Metabolite of tryptophan promoting changes in EEG signal and the oxidative status of the brain.

    PubMed

    Ferrari, Rosana; Pugini, Silvana Maria Picolli; Arce, Aldo Ivan Cespedes; Costa, Ernane Jose Xavier; de Melo, Mariza Pires

    2014-08-01

    Tryptophan is an essential amino acid precursor of neurotransmitter serotonin and triptamine. During its metabolism, indole-3-acetic acid (IAA) is generated; this substance presents both antioxidant and prooxidant effects in different biological systems in addition to hipoglicemic effects. To date, electroencephalography (EEG) has been used to evaluate the temporal effect of several substances in neurotransmission. The goal of this study was to characterize the effect of IAA in the brain by analysing the EEG signal and evaluate the oxidative status by means of biochemical parameters. The EEG was acquired by using a noninvasive method, and the brain electric signal was analysed by advanced digital signal processing techniques to determinate the energy signal filtered in different band frequencies. Furthermore, the oxidative status of the brain was investigated by measuring the activity of antioxidant enzymes and lipid peroxidation as well as blood glucose rates of the animals treated with different doses of IAA. Our results showed the relationship of IAA administration with changes in EEG signals. The oxidative status of the brain was modified by IAA after 14 days of treatment.

  12. Topographic quantitative EEG amplitude in recovered alcoholics.

    PubMed

    Pollock, V E; Schneider, L S; Zemansky, M F; Gleason, R P; Pawluczyk, S

    1992-05-01

    Topographic measures of electroencephalographic (EEG) amplitude were used to compare recovered alcoholics (n = 14) with sex- and age-matched control subjects. Delta, alpha, and beta activity did not distinguish the groups, but regional differences in theta distribution did. Recovered alcoholics showed more uniform distributions of theta amplitudes in bilateral anterior and posterior regions compared with controls. Because a minimum of 5 years had elapsed since the recovered alcoholic subjects fulfilled DSM-III-R criteria for alcohol abuse or dependence, it is unlikely these EEG theta differences reflect the effects of withdrawal.

  13. Utility of intracerebral theta burst electrical stimulation to attenuate interhemispheric inhibition and to promote motor recovery after cortical injury in an animal model.

    PubMed

    Barry, Melissa D; Boddington, Laura J; Igelström, Kajsa M; Gray, Jason P; Shemmell, Jon; Tseng, Kuei Y; Oorschot, Dorothy E; Reynolds, John N J

    2014-11-01

    Following a cerebral cortex injury such as stroke, excessive inhibition around the core of the injury is thought to reduce the potential for new motor learning. In part, this may be caused by an imbalance of interhemispheric inhibition (IHI); therefore, treatments that relieve the inhibitory drive from the healthy hemisphere to the peri-lesional area may enhance motor recovery. Theta burst stimulation delivered by transcranial magnetic stimulation has been tested as a means of normalizing IHI, but clinical results have been variable. Here we use a new rat model of synaptic IHI to demonstrate that electrical intracranial theta burst stimulation causes long-lasting changes in motor cortex excitability. Further, we show that contralateral intermittent theta burst stimulation (iTBS) blocks IHI via a mechanism involving cannabinoid receptors. Finally, we show that contralesional iTBS applied during recovery from cortical injury in rats improves the recovery of motor function. These findings suggest that theta burst stimulation delivered through implanted electrodes may be a promising avenue to explore for augmenting rehabilitation from brain injury.

  14. Theta vocabulary I

    NASA Astrophysics Data System (ADS)

    Kharchev, S.; Zabrodin, A.

    2015-08-01

    This paper is an annotated list of transformation properties and identities satisfied by the four theta functions θ1, θ2, θ3, θ4 of one complex variable, presented in a ready-to-use form. An attempt is made to reveal a pattern behind various identities for the theta-functions. It is shown that all possible 3, 4 and 5-term identities of degree four emerge as algebraic consequences of the six fundamental bilinear 3-term identities connecting the theta-functions with modular parameters τ and 2 τ.

  15. Frontal theta is a signature of successful working memory manipulation

    PubMed Central

    Itthipuripat, Sirawaj; Wessel, Jan R.; Aron, Adam R.

    2012-01-01

    It has been proposed that working memory (WM) is updated/manipulated via a fronto-basal-ganglia circuit. One way that this could happen is via the synchronization of neural oscillations. A first step towards testing this hypothesis is to clearly establish a frontal scalp EEG signature of WM manipulation. Although many EEG studies have indeed revealed frontal EEG signatures for WM, especially in the theta frequency band (3–8 Hz), few of them required subjects to manipulate WM, and of those that did, none specifically tied the EEG signature to the manipulation process per se. Here we employed a WM manipulation task that has been shown with imaging to engage the prefrontal cortex and the striatum. We adapted this task to titrate the success of WM manipulation to approximately 50%. Using time-frequency analysis of EEG, we showed that theta power is increased over frontal cortex for successful versus failed WM manipulation, specifically at the time of the manipulation event. This establishes a clear-cut EEG signature of WM manipulation. Future studies could employ this to test the fronto-basal-ganglia hypothesis of WM updating/manipulation. PMID:23109082

  16. Hippocampal theta (3-8Hz) activity during classical eyeblink conditioning in rabbits.

    PubMed

    Nokia, Miriam S; Penttonen, Markku; Korhonen, Tapani; Wikgren, Jan

    2008-07-01

    In 1978, Berry and Thompson showed that the amount of theta (3-8Hz) activity in the spontaneous hippocampal EEG predicted learning rate in subsequent eyeblink conditioning in rabbits. More recently, the absence of theta activity during the training trial has been shown to have a detrimental effect on learning rate. Here, we aimed to further explore the relationship between theta activity and classical eyeblink conditioning by determining how the relative power of hippocampal theta activity [theta/(theta+delta) ratio] changes during both unpaired control and paired training phases. We found that animals with a higher hippocampal theta ratio immediately before conditioning learned faster and also that in these animals the theta ratio was higher throughout both experimental phases. In fact, while the hippocampal theta ratio remained stable in the fast learners as a function of training, it decreased in the slow learners already during unpaired training. In addition, the presence of hippocampal theta activity enhanced the hippocampal model of the conditioned response (CR) and seemed to be beneficial for CR performance in terms of peak latency during conditioning, but did not have any effect when the animals showed asymptotic learning. Together with earlier findings, these results imply that the behavioral state in which hippocampal theta activity is absent is detrimental for learning, and that the behavioral state in which hippocampal theta activity dominates is beneficial for learning, at least before a well-learned state is achieved.

  17. Test-retest reliability of cognitive EEG

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  18. Theta-Burst LTP

    PubMed Central

    Larson, John; Munkácsy, Erin

    2014-01-01

    This review covers the spatial and temporal rules governing induction of hippocampal long-term potentiation (LTP) by theta-burst stimulation. Induction of LTP in field CA1 by high frequency stimulation bursts that resemble the burst discharges (complex-spikes) of hippocampal pyramidal neurons involves a multiple-step mechanism. A single burst is insufficient for LTP induction because it evokes both excitatory and inhibitory currents that partially cancel and limit postsynaptic depolarization. Bursts repeated at the frequency (~5 Hz) of the endogenous theta rhythm induce maximal LTP, primarily because this frequency disables feed-forward inhibition and allows sufficient postsynaptic depolarization to activate voltage-sensitive NMDA receptors. The disinhibitory process, referred to as “priming”, involves presynaptic GABA autoreceptors that inhibit GABA release. Activation of NMDA receptors allows a calcium flux into dendritic spines that serves as the proximal trigger for LTP. We include new data showing that theta-burst stimulation is more efficient than other forms of stimulation for LTP induction. In addityion, we demonstrate that associative interactions between synapses activated during theta-bursts are limited to major dendritic domains since such interactions occur within apical or basal dendritic trees but not between them. We review evidence that recordings of electrophysiological responses during theta burst stimulation can help to determine if experimental manipulations that affect LTP do so by affecting events antecedent to the induction process, such as NMDA receptor activation, or downstream signaling cascades that result from postsynaptic calcium fluxes. Finally, we argue that theta-burst LTP represents a minimal model for stable, non-decremental LTP that is more sensitive to a variety of experimental manipulations than is LTP induced by other stimulation paradigms. PMID:25452022

  19. Bispectral analysis of the rat EEG during various vigilance states.

    PubMed

    Ning, T K; Bronzino, J D

    1989-04-01

    Bispectra were computed to detect phase coupling in the cortical and hippocampal EEG of the rat during various vigilance states. For EEG's recorded from the hippocampus, significant phase coupling was obtained during REM sleep between the frequency components (6-8 Hz) associated with theta rhythm.

  20. EEG differences and cognitive style.

    PubMed

    Glass, A; Riding, R J

    1999-10-01

    Individuals differences in information processing related to cognitive style were investigated by EEG recording during cognitive tasks. Fifteen adults received the Cognitive Styles Analysis which assessed their positions on two dimensions: the wholist-analytic and the verbal-imagery. The EEG from midline, paramedial and lateral electrode clusters was recorded, while subjects viewed words presented at different rates. A button was pressed when a word was in a target conceptual category. Off-line analysis produced spectral powers for delta, theta, alpha, beta 1, beta 2 and gamma bands. For the midline, the wholists had higher output than analytics in theta and alpha, but lower in gamma. In the paramedial cluster, verbalisers had greater right power than imagers for all bands except alpha. Further, the overall power was greater on the right for imagers than verbalisers frontally, and the converse occipitally. In the lateral grouping, the wholist-verbalisers had greater overall power left antero-temporally than other sub-groups.

  1. Frontal theta as a mechanism for cognitive control

    PubMed Central

    Cavanagh, James F.; Frank, Michael J.

    2014-01-01

    Recent advancements in cognitive neuroscience have afforded a description of neural responses in terms of latent algorithmic operations. However, the adoption of this approach to human scalp EEG has been more limited, despite the ability of this methodology to quantify canonical neuronal processes. Here we provide evidence that theta band activities over the mid-frontal cortex appear to reflect a common computation used for realizing the need for cognitive control. Moreover, by virtue of inherent properties of field oscillations, these theta band processes may be used to communicate this need and subsequently implement such control across disparate brain regions. Frontal theta is thus a compelling candidate mechanism by which emergent processes such as ‘cognitive control’ may be biophysically realized. PMID:24835663

  2. Understanding the theta aurora

    NASA Astrophysics Data System (ADS)

    Fear, Robert; Milan, Steve; Carter, Jennifer; Maggiolo, Romain; Fazakerley, Andrew; Dandouras, Iannis; Mende, Stephen

    2015-04-01

    The theta aurora, first observed by Dynamics Explorer in the 1980s, is a configuration of the Earth's aurora in which auroral emissions extend into and across the polar cap in the form of a transpolar arc. It is well established that the theta aurora occurs predominantly when the interplanetary magnetic field has a northward component, but over the last thirty years various mechanisms have been put forward to explain this intriguing phenomenon. In the last couple of years, a range of evidence has accumulated which strongly suggests that the transpolar arc is formed as proposed by Milan et al. (2005): magnetotail reconnection occurs during intervals of northward IMF, which results in a local "wedge" of closed magnetospheric flux that remains trapped in the magnetotail. Precipitation on these closed field lines results in the transpolar arc analogously to the formation of the aurora in the main oval. Evidence for magnetotail reconnection as the cause of the theta aurora includes the timescales necessary to influence the location at which the transpolar arc forms, and the presence of characteristic ionospheric flows which are excited by magnetotail reconnection and which are statistically associated with transpolar arcs (Fear & Milan, 2012a,b). Most recently, direct observation has been made of a localised wedge of closed magnetic flux, "trapped" in the lobe, which was observed to move back and forth in a manner which (to our knowledge) can only be explained by the magnetotail reconnection mechanism (Fear et al., 2014). In this talk, we summarise the evidence for the formation of the theta aurora by magnetotail reconnection, and discuss the remaining challenges in obtaining a comprehensive understanding of this spectacular phenomenon.

  3. Coupling between resting cerebral perfusion and EEG.

    PubMed

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

    2013-07-01

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

  4. Midfrontal conflict-related theta-band power reflects neural oscillations that predict behavior.

    PubMed

    Cohen, Michael X; Donner, Tobias H

    2013-12-01

    Action monitoring and conflict resolution require the rapid and flexible coordination of activity in multiple brain regions. Oscillatory neural population activity may be a key physiological mechanism underlying such rapid and flexible network coordination. EEG power modulations of theta-band (4-8 Hz) activity over the human midfrontal cortex during response conflict have been proposed to reflect neural oscillations that support conflict detection and resolution processes. However, it has remained unclear whether this frequency-band-specific activity reflects neural oscillations or nonoscillatory responses (i.e., event-related potentials). Here, we show that removing the phase-locked component of the EEG did not reduce the strength of the conflict-related modulation of the residual (i.e., non-phase-locked) theta power over midfrontal cortex. Furthermore, within-subject regression analyses revealed that the non-phase-locked theta power was a significantly better predictor of the conflict condition than was the time-domain phase-locked EEG component. Finally, non-phase-locked theta power showed robust and condition-specific (high- vs. low-conflict) cross-trial correlations with reaction time, whereas the phase-locked component did not. Taken together, our results indicate that most of the conflict-related and behaviorally relevant midfrontal EEG signal reflects a modulation of ongoing theta-band oscillations that occurs during the decision process but is not phase-locked to the stimulus or to the response.

  5. Intermittent Theta-Burst Stimulation of the Right Dorsolateral Prefrontal Cortex to Promote Metaphor Comprehension in Parkinson Disease: A Case Study.

    PubMed

    Tremblay, Christina; Monetta, Laura; Langlois, Mélanie; Schneider, Cyril

    2016-01-01

    This single-case research-designed study explored whether intermittent theta-burst stimulation (iTBS) of the right dorsolateral prefrontal cortex (DLPFC) could improve metaphor comprehension in people with Parkinson disease (PD) and language impairments. A right-handed participant with PD diagnosed 9 years ago, receiving long-term treatment with levodopa, and with metaphor comprehension impairment was recruited to undergo 10 sessions of sham stimulation (in 2wk), a washout period (6wk), and then 10 sessions of iTBS (in 2wk). Clinical scores of metaphor comprehension and motor evaluation (Unified Parkinson Disease Rating Scale part III) and transcranial magnetic stimulation to test the excitability of the primary motor cortex (M1) were used at baseline, postsham, post-iTBS, and at 3 follow-ups (8, 14, and 20wk post-iTBS). Metaphor comprehension was improved after iTBS, and the highest scores were obtained 8 weeks later (P=.01). This improvement was correlated with the increase of the right M1 excitability (r=-.86, P=.03) and with the decrease of transcallosal inhibition latency from the left to the right hemisphere (r=-.88, P=.02). Sham yielded no effect (P>.05). Administration of iTBS over the right DLPFC improved metaphor comprehension likely by a long-term influence on brain synaptic plasticity, including improvement of interhemispheric dialogue. More studies are warranted to confirm these findings in larger samples of participants with PD.

  6. Increased oscillatory theta activation evoked by violent digital game events.

    PubMed

    Salminen, Mikko; Ravaja, Niklas

    2008-04-11

    The authors examined electroencephalographic (EEG) oscillatory responses to two violent events, the player character wounding and killing an opponent character with a gun, in the digital game James Bond 007: NightFire. EEG was recorded from 25 (16 male) right-handed healthy young adults. EEG data were segmented into one 1-s baseline epoch before each event and two 1-s epochs after event onset. Power estimates (microV(2)) were derived with the fast Fourier transform (FFT) for each artefact free event. Both of the studied events evoked increased occipital theta (4-6Hz) responses as compared to the pre-event baseline. The wounding event evoked also increased occipital high theta (6-8Hz) response and the killing event evoked low alpha (8-10Hz) asymmetry over the central electrodes, both relative to the pre-event baseline. The results are discussed in light of facial electromyographic and electrodermal activity responses evoked by these same events, and it is suggested that the reported EEG responses may be attributable to affective processes related to these violent game events.

  7. Destructive power dynamics of alpha-theta oscillations via spike and wave in CA3.

    PubMed

    Dong, Guoya; Chen, Xiaogang; Li, Wenwen; Cheng, Zhishuang; Ge, Manling

    2010-01-01

    The power dynamics of alpha-theta oscillations via inter-ictal spikes and waves (SWs) in CA3 is investigated by means of Hilbert transform and the statistical method based on CA3 channel of LFP(Local Field Potention) data sampled on total 6 rats in resting with sniffing and of iEEG data on total 10 patients in quiet wakefulness. The comparison of alpha-theta power is done between the inter-ictal groups and control groups. It is concluded that the inter-ictal SWs can disrupt the power of alpha-theta oscillations, leading to the decreased power after SW. Because the alpha-theta oscillations are related with the cognition, it is estimated that the inter-ictal SWs can negatively affecte the cognitive function during the inter-ictal dynamics, although the alpha-theta power will be recoverable in some days after injections, even exceed over the power level before injections.

  8. Mobile EEG and its potential to promote the theory and application of imagery-based motor rehabilitation.

    PubMed

    Kranczioch, Cornelia; Zich, Catharina; Schierholz, Irina; Sterr, Annette

    2014-01-01

    Studying the brain in its natural state remains a major challenge for neuroscience. Solving this challenge would not only enable the refinement of cognitive theory, but also provide a better understanding of cognitive function in the type of complex and unpredictable situations that constitute daily life, and which are often disturbed in clinical populations. With mobile EEG, researchers now have access to a tool that can help address these issues. In this paper we present an overview of technical advancements in mobile EEG systems and associated analysis tools, and explore the benefits of this new technology. Using the example of motor imagery (MI) we will examine the translational potential of MI-based neurofeedback training for neurological rehabilitation and applied research.

  9. EEG in Sarcoidosis Patients Without Neurological Findings.

    PubMed

    Bilgin Topçuoğlu, Özgür; Kavas, Murat; Öztaş, Selahattin; Arınç, Sibel; Afşar, Gülgün; Saraç, Sema; Midi, İpek

    2017-01-01

    Sarcoidosis is a multisystem granulomatous disease affecting nervous system in 5% to 10% of patients. Magnetic resonance imaging (MRI) is accepted as the most sensitive method for detecting neurosarcoidosis. However, the most common findings in MRI are the nonspecific white matter lesions, which may be unrelated to sarcoidosis and can occur because of hypertension, diabetes mellitus, smoking, and other inflammatory or infectious disorders, as well. Autopsy studies report more frequent neurological involvement than the ante mortem studies. The aim of this study is to assess electroencephalography (EEG) in sarcoidosis patients without neurological findings in order to display asymptomatic neurological dysfunction. We performed EEG on 30 sarcoidosis patients without diagnosis of neurosarcoidosis or prior neurological comorbidities. Fourteen patients (46.7%) showed intermittant focal and/or generalized slowings while awake and not mentally activated. Seven (50%) of these 14 patients with EEG slowings had nonspecific white matter changes while the other half showed EEG slowings in the absence of MRI changes. We conclude that EEG slowings, when normal variants (psychomotor variant, temporal theta of elderly, frontal theta waves) are eliminated, may be an indicator of dysfunction in brain activity even in the absence of MRI findings. Hence, EEG may contribute toward detecting asymptomatic neurological dysfunction or probable future neurological involvement in sarcoidosis patients.

  10. Developmental changes of BOLD signal correlations with global human EEG power and synchronization during working memory.

    PubMed

    Michels, Lars; Lüchinger, Rafael; Koenig, Thomas; Martin, Ernst; Brandeis, Daniel

    2012-01-01

    In humans, theta band (5-7 Hz) power typically increases when performing cognitively demanding working memory (WM) tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent) signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and higher frequency band synchronization is modulated during WM. Yet, little is known about the link between BOLD, EEG power, and EEG synchronization during WM, and how these measures develop with human brain maturation or relate to behavioral changes. We examined EEG-BOLD signal correlations from 18 young adults and 15 school-aged children for age-dependent effects during a load-modulated Sternberg WM task. Frontal load (in-)dependent EEG theta power was significantly enhanced in children compared to adults, while adults showed stronger fMRI load effects. Children demonstrated a stronger negative correlation between global theta power and the BOLD signal in the default mode network relative to adults. Therefore, we conclude that theta power mediates the suppression of a task-irrelevant network. We further conclude that children suppress this network even more than adults, probably from an increased level of task-preparedness to compensate for not fully mature cognitive functions, reflected in lower response accuracy and increased reaction time. In contrast to power, correlations between instantaneous theta global field synchronization and the BOLD signal were exclusively positive in both age groups but only significant in adults in the frontal-parietal and posterior cingulate cortices. Furthermore, theta synchronization was weaker in children and was--in contrast to EEG power--positively correlated with response accuracy in both age groups. In summary we conclude that theta EEG-BOLD signal correlations differ between spectral power and synchronization and that

  11. Theta vocabulary II. Multidimensional case

    NASA Astrophysics Data System (ADS)

    Kharchev, S.; Zabrodin, A.

    2016-06-01

    It is shown that the Jacobi and Riemann identities of degree four for the multidimensional theta functions as well as the Weierstrass identities emerge as algebraic consequences of the fundamental multidimensional binary identities connecting the theta functions with Riemann matrices τ and 2 τ.

  12. Rostral anterior cingulate activity generates posterior versus anterior theta activity linked to agentic extraversion.

    PubMed

    Chavanon, Mira-Lynn; Wacker, Jan; Stemmler, Gerhard

    2011-06-01

    Recent research using the resting electroencephalogram (EEG) showed that posterior versus anterior theta activity (around 4-8 Hz) is consistently associated with agency, reflecting the dopaminergic core of extraversion (i.e., incentive motivation, positive emotion). Neuroimaging studies using various methodologies and experimental paradigms have converged on the anterior cingulate cortex (ACC) as a neurophysiological correlate of extraversion. The aim of the present study is integrate these lines of research by testing the hypothesis that posterior versus anterior EEG theta is at least partly based on ACC theta activity. Resting EEG data were analyzed in N = 78 healthy, male participants extremely high or low in agentic extraversion (aE). Using the low-resolution electromagnetic tomography algorithm, we localized the sources of aE-dependent intracerebral theta activity within rostral subdivisions of the ACC. The posterior versus anterior index and theta current density within the rostral ACC were significantly correlated (r = -.52), and both displayed high retest stability across 5 hr and were associated with traits from the aE spectrum. These neurophysiological correlates of aE and their possible functional significance are discussed.

  13. Characterization of the Theta to Beta Ratio in ADHD: Identifying Potential Sources of Heterogeneity

    ERIC Educational Resources Information Center

    Loo, Sandra K.; Cho, Alexander; Hale, T. Sigi; McGough, James; McCracken, James; Smalley, Susan L.

    2013-01-01

    Objective: The goal of this study is to characterize the theta to beta ratio (THBR) obtained from electroencephalogram (EEG) measures, in a large sample of community and clinical participants with regard to (a) ADHD diagnosis and subtypes, (b) common psychiatric comorbidities, and (c) cognitive correlates. Method: The sample includes 871…

  14. Autoregressive and bispectral analysis techniques: EEG applications.

    PubMed

    Ning, T; Bronzino, J D

    1990-01-01

    Some basic properties of autoregressive (AR) modeling and bispectral analysis are reviewed, and examples of their application in electroencephalography (EEG) research are provided. A second-order AR model was used to score cortical EEGs in order. In tests performed on five adult rats to distinguish between different vigilance states such a quiet-waking (QW), rapid-eye-movement (REM), and slow-wave sleep (SWS), SWS activity was correctly identified over 96% of the time, and a 95% agreement rate was achieved in recognizing the REM sleep stage. In a bispectral analysis of the rat EEG, third-order cumulant (TOC) sequences of 32 epochs belonging to the same vigilance state were estimated and then averaged. Preliminary results have shown that bispectra of hippocampal EEGs during REM Sleep exhibit significant quadratic phase couplings between frequencies in the 6-8-Hz range, associated with the theta rhythm.

  15. Inactivation of the medial mammillary nucleus attenuates theta rhythm activity in the hippocampus in urethane-anesthetized rats.

    PubMed

    Żakowski, Witold; Braszka, Łukasz; Zawistowski, Piotr; Orzeł-Gryglewska, Jolanta; Jurkowlaniec, Edyta

    2017-04-03

    Although the importance of the mammillary body for memory and learning processes is well known, its exact role has remained vague. The fact, that many neurons in one nucleus of the mammillary body in rats, i.e. the medial mammillary nucleus (MM), fires according with hippocampal theta rhythm, makes this structure crucial for a theta rhythm signaling in so-called extended hippocampal system. These neurons are driven by descending projections from the hippocampal formation, but it is still unknown whether the mammillary body only conveys theta rhythm or may also modulate it. In the present study, we investigated the effect of pharmacological inactivation (local infusion of 0.5μl of 20% procaine hydrochloride solution) of the MM on hippocampal theta rhythm in urethane-anesthetized rats. We found that intra-MM procaine microinjections suppress sensory-elicited theta rhythm in the hippocampus by reduction of its amplitude, but not the frequency. Procaine infusion decreased the EEG signal power of low theta frequency bands, i.e. 3-5Hz, down to 9.2% in 3-4Hz band in comparison to pre-injection conditions. After water infusion (control group) no changes of hippocampal EEG signal power were observed. Our findings showed for the first time that inactivation of the MM leads to a disruption of hippocampal theta rhythm in the rat, which may suggest that the mammillary body can regulate theta rhythm signaling in the extended hippocampal system.

  16. Centrotemporal spikes during NREM sleep: The promoting action of thalamus revealed by simultaneous EEG and fMRI coregistration.

    PubMed

    Mirandola, Laura; Cantalupo, Gaetano; Vaudano, Anna Elisabetta; Avanzini, Pietro; Ruggieri, Andrea; Pisani, Francesco; Cossu, Giuseppe; Tassinari, Carlo Alberto; Nichelli, Paolo Frigio; Benuzzi, Francesca; Meletti, Stefano

    2013-01-01

    Benign childhood epilepsy with centrotemporal spikes (BECTS) has been investigated through EEG-fMRI with the aim of localizing the generators of the epileptic activity, revealing, in most cases, the activation of the sensory-motor cortex ipsilateral to the centrotemporal spikes (CTS). In this case report, we investigated the brain circuits hemodynamically involved by CTS recorded during wakefulness and sleep in one boy with CTS and a language disorder but without epilepsy. For this purpose, the patient underwent EEG-fMRI coregistration. During the "awake session", fMRI analysis of right-sided CTS showed increments of BOLD signal in the bilateral sensory-motor cortex. During the "sleep session", BOLD increments related to right-sided CTS were observed in a widespread bilateral cortical-subcortical network involving the thalamus, basal ganglia, sensory-motor cortex, perisylvian cortex, and cerebellum. In this patient, who fulfilled neither the diagnostic criteria for BECTS nor that for electrical status epilepticus in sleep (ESES), the transition from wakefulness to sleep was related to the involvement of a widespread cortical-subcortical network related to CTS. In particular, the involvement of a thalamic-perisylvian neural network similar to the one previously observed in patients with ESES suggests a common sleep-related network dysfunction even in cases with milder phenotypes without seizures. This finding, if confirmed in a larger cohort of patients, could have relevant therapeutic implication.

  17. Can prefrontal theta cordance differentiate between depression recovery and dissimulation?

    PubMed

    Kopecek, Miloslav; Sos, Peter; Brunovsky, Martin; Bares, Martin; Stopkova, Pavla; Krajca, Vladimir

    2007-08-01

    We present a case report of a 37-year old woman diagnosed with depressive disorder, first episode, who was admitted into a psychiatric hospital after a failed suicidal attempt. She responded to antidepressant therapy, as evidenced by a >50% reduction in MADRS total score. She was discharged after 4 weeks of treatment, denying any suicidal ideations. The following day the patient committed suicide; she burned herself to death. It is very likely that the patient dissimulated her symptoms and ideations. Subsequently, her quantitative EEG records were retrospectively analyzed. An increase of prefrontal theta cordance value after the first week of mirtazapine therapy was found. Recently three small studies have revealed that decrease of prefrontal theta cordance after 1 week of antidepressant administration can predict clinical response in patients with unipolar depression. In our previous study the absence of a decreased theta prefrontal cordance was associated with lack of treatment response with NPV 1.0 (Bares et al., 2007). Thus, we hypothesize that prefrontal theta cordance could become an objective marker of change of depressive symptoms, independent of patients' compliance and symptom dissimulation, more precise than objective and self-rated depression rating scales.

  18. [Evaluation of mental workload of short-term memory task by secondary task performance and frontal midline theta rhythm].

    PubMed

    Nakashima, K; Sato, H

    1992-03-01

    The purpose of the present study was to evaluate the mental workload of short-term memory task by two objective measures, the secondary task performance and the frontal midline theta rhythm (Fm theta) of the electroencephalogram (EEG). First, to choose Fm theta appearance subjects EEGs were recorded for 18 male students during performing additional task. On Fm theta appearance subjects (8 males) a series of short-term memory task with changed number of memorable figures was imposed as the primary task, and tracking task as the secondary task. The task that presents seven numbers will be over the subjects' limits of short-term memory, and it was the threshold that the subjects' mental workload will be increased.

  19. 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.

  20. EEG (Electroencephalogram)

    MedlinePlus

    ... simple calculations, read a paragraph, look at a picture, breathe deeply (hyperventilate) for a few minutes, or look at a flashing light. Video is frequently recorded during the EEG. Your body motions are captured by a video camera while the ...

  1. Continuous theta burst transcranial magnetic stimulation affects brain functional connectivity.

    PubMed

    Dan Cao; Yingjie Li; Ling Wei; Yingying Tang

    2016-08-01

    Prefrontal cortex (PFC) plays an important role in the emotional processing as well as in the functional brain network. Hyperactivity in the right dorsolateral prefrontal cortex (DLPFC) would be found in anxious participants. However, it is still unclear what the role of PFC played in a resting functional network. Continuous theta burst transcranial magnetic stimulation (cTBS) is an effective tool to create virtual lesions on brain regions. In this paper, we applied cTBS over right prefrontal area, and investigated the effects of cTBS on the brain activity for functional connectivity by the method of graph theory. We recorded 64-channels EEG on thirteen healthy participants in the resting condition and emotional tasks before and after 40 s of cTBS. This work focused on the effect of cTBS on cortical activities in the resting condition by calculating the coherence between EEG channels and building functional networks before and after cTBS in the delta, theta, alpha and beta bands. Results revealed that 1) The functional connectivity after cTBS was significantly increased compared with that before cTBS in delta, theta, alpha and beta bands in the resting condition; 2) The efficiency-cost reached the maximum before and after cTBS both with the cost about 0.3 in the bands above, which meant that the information transmission of functional brain network with this cost was highly efficient; 3) the clustering coefficient and path length after cTBS was significantly increased in delta, theta and beta bands. In conclusion, cTBS over PFC indeed enhanced the functional connectivity in the resting condition. In addition, the information transmission in the resting brain network was highly efficient with the cost about 0.3.

  2. Permutation symmetry for theta functions

    SciTech Connect

    Carlson, B.C.

    2011-01-21

    This paper does for combinations of theta functions most of what Carlson (2004) [1] did for Jacobian elliptic functions. In each case the starting point is the symmetric elliptic integral R{sub F} of the first kind. Its three arguments (formerly squared Jacobian elliptic functions but now squared combinations of theta functions) differ by constants. Symbols designating the constants can often be used to replace 12 equations by three with permutation symmetry (formerly in the letters c, d, n for the Jacobian case but now in the subscripts 2, 3, 4 for theta functions). Such equations include derivatives and differential equations, bisection and duplication relations, addition formulas (apparently new for theta functions), and an example of pseudoaddition formulas.

  3. Does immobilization of dependent hand promote adaptative changes in cerebral cortex? An analysis through qEEG asymmetry.

    PubMed

    Manaia, Fernanda; Teixeira, Silmar; Velasques, Bruna; Bittencourt, Juliana; Salles, José Inácio; Arias-Carrión, Oscar; Basile, Luis F; Peressutti, Caroline; de Carvalho, Marcele Regine; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro; Machado, Sérgio

    2013-03-22

    This study aimed to elucidate electrophysiological and cortical mechanisms involved when 15 healthy right-handed subjects executed an index finger flexion and extension task before and after hand immobilization, using qEEG beta band (13-30Hz) asymmetry. This beta band is involved in motor activity and sensorial factors. Our hypothesis is that an increase in beta band asymmetry in pre-frontal, motor and parietal areas will occur in post-hand immobilization, because these areas need to reorganize for new planning, preparation and voluntary motor control. We found increase in beta band asymmetry during post-treatment task. We concluded that beta band asymmetry plays an important role in the analysis of cortical changes in several brain areas when associated to motor task. Furthermore, we assume that 48h of hand immobilization change cortical functioning.

  4. Correlation of hippocampal theta rhythm with changes in cutaneous temperature. [evoked neuron response in thermoregulation

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.; Saleh, M. A.; Karem, R. D.

    1974-01-01

    A possible role for the hippocampus in alerting an animal to changes in cutaneous temperature was examined. Following local warming or cooling of the ears of unanesthetized, loosely restrained rabbits, theta waves (4-7 Hz EEG waves) were recorded from electrodes straddling the hippocampus. The onset of the hippocampal theta rhythm was correlated with changes in cutaneous temperature, an observation consistent with studies indicating that the theta rhythm is a nonspecific response evoked by stimulation of several sensory modalities. Additional data from cats and rabbits were correlated with specific neurons within the hippocampus, namely pyramidal cells. Post stimulus time histograms obtained by excitation of the dorsal fornix were interpreted in terms of excitatory and inhibitory inputs to pyramidal cells. Thus, the theta rhythm, which appears to be evoked by changes in cutaneous temperature, can be related to a specific type of hippocampal neuron which is in turn connected with other areas of the brain involved in temperature regulation.

  5. Local and Widely Distributed EEG Activity in Schizophrenia With Prevalence of Negative Symptoms.

    PubMed

    Grin-Yatsenko, Vera A; Ponomarev, Valery A; Pronina, Marina V; Poliakov, Yury I; Plotnikova, Irina V; Kropotov, Juri D

    2017-01-01

    We evaluated EEG frequency abnormalities in resting state (eyes closed and eyes open) EEG in a group of chronic schizophrenia patients as compared with healthy subjects. The study included 3 methods of analysis of deviation of EEG characteristics: genuine EEG, current source density (CSD), and group independent component (gIC). All 3 methods have shown that the EEG in schizophrenia patients is characterized by enhanced low-frequency (delta and theta) and high-frequency (beta) activity in comparison with the control group. However, the spatial pattern of differences was dependent on the type of method used. Comparative analysis has shown that increased EEG power in schizophrenia patients apparently concerns both widely spatially distributed components and local components of signal. Furthermore, the observed differences in the delta and theta range can be described mainly by the local components, and those in the beta range mostly by spatially widely distributed ones. The possible nature of the widely distributed activity is discussed.

  6. Theta phase locking across the neocortex reflects cortico-hippocampal recursive communication during goal conflict resolution.

    PubMed

    Moore, Roger A; Gale, Anthony; Morris, Paul H; Forrester, Dave

    2006-06-01

    EEG theta coherence, EEG theta power and subjective levels of response were examined in a continuous monitoring target detection task where periodic goal conflicts were introduced as 34 participants progressed through a stimulus sequence leading to response. EEG theta coherence revealed increases in phase locking between cortical areas at specific task stages involving goal conflict. Theta power also increased at points of goal conflict. The temporal characteristics of subjective response (measured continuously throughout the task) indicated a delay between participants actually experiencing goal conflict and overt indications of conflict. The starting point for the study was based on a specific aspect of Gray and McNaughton's [Gray, J.A., McNaughton, N., 2000. The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-Hippocampal System, 2nd ed. Oxford University Press, Oxford] behavioural inhibition system model-namely, septo-hippocampal system involvement in the resolution of goal conflicts. We drew on Gray and McNaughton's [Gray, J.A., McNaughton, N., 2000. The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-Hippocampal system, 2nd ed. Oxford University Press, Oxford] suggestion that septo-hippocampal involvement in this process is reflected by EEG theta. While their theory explains many of our findings, we also drew upon Given's [Givens, B., 1996. Stimulus-evoked reseting of the dentate theta rhythm: relation to working memory. Neuroreport 8 (1), 159-163] proposal that the dentate theta rhythm is reset by behaviourally relevant stimuli. We made further proposals based on Makeig et al.'s [Makeig, S., Westerfield, M., Jung, T.-P., Enghoff, S., Townsend, J., Courchesne, E., Sejnowski, T.J., 2002. Dynamic brain sources of visual evoked responses. Science 295, 690-694] view that specific stimulus events invoke concurrent phase resetting and transient frequency domain coherence across different areas of neocortex. Relations

  7. Why don't you like me? Midfrontal theta power in response to unexpected peer rejection feedback.

    PubMed

    van der Molen, M J W; Dekkers, L M S; Westenberg, P M; van der Veen, F M; van der Molen, M W

    2017-02-01

    Social connectedness theory posits that the brain processes social rejection as a threat to survival. Recent electrophysiological evidence suggests that midfrontal theta (4-8Hz) oscillations in the EEG provide a window on the processing of social rejection. Here we examined midfrontal theta dynamics (power and inter-trial phase synchrony) during the processing of social evaluative feedback. We employed the Social Judgment paradigm in which 56 undergraduate women (mean age=19.67 years) were asked to communicate their expectancies about being liked vs. disliked by unknown peers. Expectancies were followed by feedback indicating social acceptance vs. rejection. Results revealed a significant increase in EEG theta power to unexpected social rejection feedback. This EEG theta response could be source-localized to brain regions typically reported during activation of the saliency network (i.e., dorsal anterior cingulate cortex, insula, inferior frontal gyrus, frontal pole, and the supplementary motor area). Theta phase dynamics mimicked the behavior of the time-domain averaged feedback-related negativity (FRN) by showing stronger phase synchrony for feedback that was unexpected vs. expected. Theta phase, however, differed from the FRN by also displaying stronger phase synchrony in response to rejection vs. acceptance feedback. Together, this study highlights distinct roles for midfrontal theta power and phase synchrony in response to social evaluative feedback. Our findings contribute to the literature by showing that midfrontal theta oscillatory power is sensitive to social rejection but only when peer rejection is unexpected, and this theta response is governed by a widely distributed neural network implicated in saliency detection and conflict monitoring.

  8. EEG Multiresolution Analysis Using Wavelet Transform

    DTIC Science & Technology

    2007-11-02

    Wavelet transform (WT) is a new multiresolution time-frequency analysis method. WT possesses well localization feature both in tine and frequency...plays a key role in the diagnosing diseases and is useful for both physiological research and medical applications. Using the dyadic wavelet ... transform the EEG signals are successfully decomposed to the alpha rhythm (8-13Hz) beta rhythm (14-30Hz) theta rhythm (4-7Hz) and delta rhythm (0.3-3Hz) and

  9. [Quantitative evaluation of inhibitory effects of epileptic spikes on theta rhythms in the network of hippocampal CA3 and entorhinal cortex in patients with temporal lobe epilepsy].

    PubMed

    Ge, Man-Ling; Guo, Jun-Dan; Chen, Sheng-Hua; Zhang, Ji-Chang; Fu, Xiao-Xuan; Chen, Yu-Min

    2017-02-25

    Epileptic spike is an indicator of hyper-excitability and hyper-synchrony in the neural networks. The inhibitory effects of spikes on theta rhythms (4-8 Hz) might be helpful to understand the mechanism of epileptic damage on the cognitive functions. To quantitatively evaluate the inhibitory effects of spikes on theta rhythms, intracerebral electroencephalogram (EEG) recordings with both sporadic spikes (SSs) and spike-free transient period between adjacent spikes were selected in 4 patients in the status of rapid eyes movement (REM) sleep with temporal lobe epilepsy (TLE) under the pre-surgical monitoring. The electrodes of hippocampal CA3 and entorhinal cortex (EC) were employed, since CA3 and EC built up one of key loops to investigate cognition and epilepsy. These SSs occurred only in CA3, only in EC, or in both CA3 and EC synchronously. Theta power was respectively estimated around SSs and during the spike-free transient period by Gabor wavelet transform and Hilbert transform. The intermittent extent was then estimated to represent for the loss of theta rhythms during the spike-free transient period. The following findings were obtained: (1) The prominent rhythms were in theta frequency band; (2) The spikes could transiently reduce theta power, and the inhibitory effect was severer around SSs in both CA3 and EC synchronously than that around either SSs only in EC or SSs only in CA3; (3) During the spike-free transient period, theta rhythms were interrupted with the intermittent theta rhythms left and theta power level continued dropping, implying the inhibitory effect was sustained. Additionally, the intermittent extent of theta rhythms was converged to the inhibitory extent around SSs; (4) The average theta power level during the spike-free transient period might not be in line with the inhibitory extent of theta rhythms around SSs. It was concluded that the SSs had negative effects on theta rhythms transiently and directly, the inhibitory effects aroused by

  10. Analysis of EEG patterns and genotypes in patients with Angelman syndrome.

    PubMed

    Vendrame, Martina; Loddenkemper, Tobias; Zarowski, Marcin; Gregas, Matt; Shuhaiber, Hans; Sarco, Dean P; Morales, Augusto; Nespeca, Mark; Sharpe, Cia; Haas, Kevin; Barnes, Gregory; Glaze, Daniel; Kothare, Sanjeev V

    2012-03-01

    We prospectively analyzed EEGs from participants in the ongoing NIH Rare Diseases Clinical Research Network Angelman Syndrome Natural History Study. Of the one-hundred-sixty enrolled patients (2006-2010), 115 had complete data (58 boys, median age 3.6 years). Distinct EEG findings were intermittent rhythmic delta waves (83.5%), interictal epileptiform discharges (74.2%), intermittent rhythmic theta waves (43.5%), and posterior rhythm slowing (43.5%). Centro-occipital and centro-temporal delta waves decreased with age (p=0.01, p=0.03). There were no specific correlations between EEG patterns and genotypes. A classification tree allowed the prediction of deletions class-1 (5.9 Mb) in patients with intermittent theta waves in <50% of EEG and interictal epileptiform abnormalities; UPD, UBE3A mutation or imprinting defects in patients with intermittent theta in <50% of EEG without interictal epileptiform abnormalities; deletions class-2 (5.0 Mb) in patients with >50% theta and normal posterior rhythm; atypical deletions in patients with >50% theta but abnormal posterior rhythm. EEG patterns are important biomarkers in Angelman syndrome and may suggest the underlying genetic etiology.

  11. Working memory performance inversely predicts spontaneous delta and theta-band scaling relations.

    PubMed

    Euler, Matthew J; Wiltshire, Travis J; Niermeyer, Madison A; Butner, Jonathan E

    2016-04-15

    Electrophysiological studies have strongly implicated theta-band activity in human working memory processes. Concurrently, work on spontaneous, non-task-related oscillations has revealed the presence of long-range temporal correlations (LRTCs) within sub-bands of the ongoing EEG, and has begun to demonstrate their functional significance. However, few studies have yet assessed the relation of LRTCs (also called scaling relations) to individual differences in cognitive abilities. The present study addressed the intersection of these two literatures by investigating the relation of narrow-band EEG scaling relations to individual differences in working memory ability, with a particular focus on the theta band. Fifty-four healthy adults completed standardized assessments of working memory and separate recordings of their spontaneous, non-task-related EEG. Scaling relations were quantified in each of the five classical EEG frequency bands via the estimation of the Hurst exponent obtained from detrended fluctuation analysis. A multilevel modeling framework was used to characterize the relation of working memory performance to scaling relations as a function of general scalp location in Cartesian space. Overall, results indicated an inverse relationship between both delta and theta scaling relations and working memory ability, which was most prominent at posterior sensors, and was independent of either spatial or individual variability in band-specific power. These findings add to the growing literature demonstrating the relevance of neural LRTCs for understanding brain functioning, and support a construct- and state-dependent view of their functional implications.

  12. Power spectral analysis of the EEG following protein malnutrition.

    PubMed

    Bronzino, J D; Stisser, P; Forbes, W B; Tracy, C; Resnick, O; Morgane, P J

    1980-01-01

    In these studies, power spectral analysis techniques were utilized to quantify the EEG obtained from rats reared on either an 8% or 25% casein diet during various vigilance states at two stages of development: (1) adulthood-90 to 120 days old; and (2) immediately after weaning-22 to 23 days old. It was found that the cortical EEG contained relatively more power in the low frequencies (ie., 0.5 to 10 Hz) for the 22-23 day old animals than for the 90-120 day old rats, especially during the slow wave sleep states-SWS1 and SWS2. Theta activity (5-8 Hz) in the hippocampus was shown to have greater power for the 22-23 day old group than for the older animals during both REM sleep and waking. Analyses of power spectral data and other indices of the frequency distribution of the hippocampal EEG indicated that those animals subjected to protein malnutrition have significantly more power in the theta band during REM sleep than the normal adult group. Since it was also noted that the hippocampal EEG obtained from the 22-23 day old group contained relatively more power in the theta band than the 90-120 day old group, the dietary treatment effect might be intrepreted as an instance of retarded development associated with protein malnutrition. Thus, a significant effect of the dietary manipulation used in the study may be largely on the system responsible for regulating theta activity.

  13. Effect of mental task load on fronto-central theta activity in a deep saturation dive to 450 msw.

    PubMed

    Lorenz, J; Lorenz, B; Heineke, M

    1992-07-01

    The increase of theta activity (4-7 Hz) in the electroencephalogram (EEG) during deep diving is commonly attributed to pathophysiologic mechanisms underlying the high pressure neurologic syndrome. The aim of this study was to clarify whether more precise cognitive aspects of the condition may be described in which theta activity occurs during a deep dive. Among 4 divers who were repeatedly examined during the GUSI 14 dive to 450 msw, 3 divers exhibited a pronounced correlation between short-term memory load, as varied by the memory set size of Sternberg's memory search task (MST), and the size of a distinct peak in the theta band of the EEG-power spectrum. The power of this peak was greatest in the fronto-central electrode position (Fz), increased dramatically during MST-performance at pressure, and failed to subside fully 1 day before surfacing. Despite the close dependency of observed theta activity on cognitive demands, no consistent correlation with performance measures (mean reaction time and errors) was found. In one diver, theta waves of similar morphology appeared in the resting EEG and increased significantly during the dive. We suggest two alternative explanations for the positive interaction of memory load and hyperbaric exposure on Fz-theta: a) Both factors induce a state of increased mental effort or selectivity of attention, known to be accompanied by frontal theta activity from normobaric studies. b) Pressure abnormally facilitates or patterns rhythmical excitations underlying theta activity that would occur naturally to a lesser extent during certain mental activities, learning, or repetitive short-term memory operations.

  14. 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.

  15. Association of Electroencephalography (EEG) Power Spectra with Corneal Nerve Fiber Injury in Retinoblastoma Patients.

    PubMed

    Liu, Jianliang; Sun, Juanjuan; Diao, Yumei; Deng, Aijun

    2016-09-04

    BACKGROUND In our clinical experience we discovered that EEG band power may be correlated with corneal nerve injury in retinoblastoma patients. This study aimed to investigate biomarkers obtained from electroencephalography (EEG) recordings to reflect corneal nerve injury in retinoblastoma patients. MATERIAL AND METHODS Our study included 20 retinoblastoma patients treated at the Department of Ophthalmology, Affiliated Hospital of Weifang Medical University between 2010 and 2014. Twenty normal individuals were included in the control group. EEG activity was recorded continuously with 32 electrodes using standard EEG electrode placement for detecting EEG power. A cornea confocal microscope was used to examine corneal nerve injury in retinoblastoma patients and normal individuals. Spearman rank correlation analysis was used to analyze the correlation between corneal nerve injury and EEG power changes. The sensitivity and specificity of changed EEG power in diagnosis of corneal nerve injury were also analyzed. RESULTS The predominantly slow EEG oscillations changed gradually into faster waves in retinoblastoma patients. The EEG pattern in retinoblastoma patients was characterized by a distinct increase of delta (P<0.01) and significant decrease of theta power P<0.05). Corneal nerves were damaged in corneas of retinoblastoma patients. Corneal nerve injury was positively correlated with delta EEG spectra power and negatively correlated with theta EEG spectra power. The diagnostic sensitivity and specificity by compounding in the series were 60% and 67%, respectively. CONCLUSIONS Changes in delta and theta of EEG appear to be associated with occurrence of corneal nerve injury. Useful information can be provided for evaluating corneal nerve damage in retinoblastoma patients through analyzing EEG power bands.

  16. Frontal theta links prediction errors to behavioral adaptation in reinforcement learning.

    PubMed

    Cavanagh, James F; Frank, Michael J; Klein, Theresa J; Allen, John J B

    2010-02-15

    Investigations into action monitoring have consistently detailed a frontocentral voltage deflection in the event-related potential (ERP) following the presentation of negatively valenced feedback, sometimes termed the feedback-related negativity (FRN). The FRN has been proposed to reflect a neural response to prediction errors during reinforcement learning, yet the single-trial relationship between neural activity and the quanta of expectation violation remains untested. Although ERP methods are not well suited to single-trial analyses, the FRN has been associated with theta band oscillatory perturbations in the medial prefrontal cortex. Mediofrontal theta oscillations have been previously associated with expectation violation and behavioral adaptation and are well suited to single-trial analysis. Here, we recorded EEG activity during a probabilistic reinforcement learning task and fit the performance data to an abstract computational model (Q-learning) for calculation of single-trial reward prediction errors. Single-trial theta oscillatory activities following feedback were investigated within the context of expectation (prediction error) and adaptation (subsequent reaction time change). Results indicate that interactive medial and lateral frontal theta activities reflect the degree of negative and positive reward prediction error in the service of behavioral adaptation. These different brain areas use prediction error calculations for different behavioral adaptations, with medial frontal theta reflecting the utilization of prediction errors for reaction time slowing (specifically following errors), but lateral frontal theta reflecting prediction errors leading to working memory-related reaction time speeding for the correct choice.

  17. Social exclusion modulates event-related frontal theta and tracks ostracism distress in children

    PubMed Central

    van Noordt, Stefon J.R.; White, Lars O.; Wu, Jia; Mayes, Linda C.; Crowley, Michael J.

    2015-01-01

    Social exclusion is a potent elicitor of distress. Previous studies have shown that medial frontal theta oscillations are modulated by the experience of social exclusion. Using the Cyberball paradigm, we examined event-related dynamics of theta power in the EEG at medial frontal sites while children aged 8–12 years were exposed to conditions of fair play and social exclusion. Using an event-related design, we found that medial frontal theta oscillations (4–8 Hz) increase during both early (i.e., 200–400 ms) and late (i.e., 400–800 ms) processing of rejection events during social exclusion relative to perceptually identical “not my turn” events during inclusion. Importantly, we show that only for the later time window (400–800 ms) slow-wave theta power tracks self-reported ostracism distress. Specifically, greater theta power at medial frontal sites to “rejection” events predicted higher levels of ostracism distress. Alpha and beta oscillations for rejection events were unrelated to ostracism distress at either 200–400 ms or 400–800 ms time windows. Our findings extend previous studies by showing that medial frontal theta oscillations for rejection events are a neural signature of social exclusion, linked to experienced distress in middle childhood. PMID:26048623

  18. Social exclusion modulates event-related frontal theta and tracks ostracism distress in children.

    PubMed

    van Noordt, Stefon J R; White, Lars O; Wu, Jia; Mayes, Linda C; Crowley, Michael J

    2015-09-01

    Social exclusion is a potent elicitor of distress. Previous studies have shown that medial frontal theta oscillations are modulated by the experience of social exclusion. Using the Cyberball paradigm, we examined event-related dynamics of theta power in the EEG at medial frontal sites while children aged 8-12 years were exposed to conditions of fair play and social exclusion. Using an event-related design, we found that medial frontal theta oscillations (4-8Hz) increase during both early (i.e., 200-400ms) and late (i.e., 400-800ms) processing of rejection events during social exclusion relative to perceptually identical "not my turn" events during inclusion. Importantly, we show that only for the later time window (400-800ms) slow-wave theta power tracks self-reported ostracism distress. Specifically, greater theta power at medial frontal sites to "rejection" events predicted higher levels of ostracism distress. Alpha and beta oscillations for rejection events were unrelated to ostracism distress at either 200-400ms or 400-800ms time windows. Our findings extend previous studies by showing that medial frontal theta oscillations for rejection events are a neural signature of social exclusion, linked to experienced distress in middle childhood.

  19. COMPARISON OF EEG CHANGES PRODUCED BY CARBARYL (CARBAMATE), PERMETHRIN (TYPE I PYRETHROID), AND DELTAMETHRIN (TYPE II PYRETHROID)

    EPA Science Inventory

    We have reported that treatment with carbaryl may alter Theta activity in the EEG (Lyke et al., Toxicologist, 108(S-1):441, 2009). In this study, we examined the ability to detect changes in EEG activity produced by pesticides with different modes of action. Long Evans rats were ...

  20. Theta synchronization predicts efficient memory encoding of concrete and abstract nouns.

    PubMed

    Weiss, S; Müller, H M; Rappelsberger, P

    2000-08-03

    Functional and topographical differences between processing of spoken nouns which were remembered or which were forgotten were shown by means of EEG coherence analysis. Later recalled nouns were related with increased neuronal synchronization (= cooperation) between anterior and posterior brain regions regardless of presented word category (either concrete or abstract nouns). However, theta coherence exhibited topographical differences during encoding of concrete and abstract nouns whereby former were related with higher short-range (mainly intrahemispheric), later with higher long-range (mainly interhemispheric) coherence. Thus, theta synchronization possibly is a general phenomenon always occurring if task demand increases and more efficient information processing is required. Measurement of EEG coherence yields new information about the neuronal interaction of involved brain regions during memory encoding of different word classes.

  1. 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

  2. Grid cells and theta as oscillatory interference: theory and predictions.

    PubMed

    Burgess, Neil

    2008-01-01

    The oscillatory interference model [Burgess et al. (2007) Hippocampus 17:801-802] of grid cell firing is reviewed as an algorithmic level description of path integration and as an implementation level description of grid cells and their inputs. New analyses concern the relationships between the variables in the model and the theta rhythm, running speed, and the intrinsic firing frequencies of grid cells. New simulations concern the implementation of velocity-controlled oscillators (VCOs) with different preferred directions in different neurons. To summarize the model, the distance traveled along a specific direction is encoded by the phase of a VCO relative to a baseline frequency. Each VCO is an intrinsic membrane potential oscillation whose frequency increases from baseline as a result of depolarization by synaptic input from speed modulated head-direction cells. Grid cell firing is driven by the VCOs whose preferred directions match the current direction of motion. VCOs are phase-reset by location-specific input from place cells to prevent accumulation of error. The baseline frequency is identified with the local average of VCO frequencies, while EEG theta frequency is identified with the global average VCO frequency and comprises two components: the frequency at zero speed and a linear response to running speed. Quantitative predictions are given for the inter-relationships between a grid cell's intrinsic firing frequency and grid scale, the two components of theta frequency, and the running speed of the animal. Qualitative predictions are given for the properties of the VCOs, and the relationship between environmental novelty, the two components of theta, grid scale and place cell remapping.

  3. Patterns of theta oscillation reflect the neural basis of individual differences in epistemic motivation

    PubMed Central

    Mussel, Patrick; Ulrich, Natalie; Allen, John J. B.; Osinsky, Roman; Hewig, Johannes

    2016-01-01

    Theta oscillations in the EEG have been shown to reflect ongoing cognitive processes related to mental effort. Here, we show that the pattern of theta oscillation in response to varying cognitive demands reflects stable individual differences in the personality trait epistemic motivation: Individuals with high levels of epistemic motivation recruit relatively more cognitive resources in response to situations possessing high, compared to low, cognitive demand; individuals with low levels do not show such a specific response. Our results provide direct evidence for the theory of the construct need for cognition and add to our understanding of the neural processes underlying theta oscillations. More generally, we provide an explanation how individual differences in personality traits might be represented on a neural level. PMID:27380648

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

    PubMed Central

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

    2016-01-01

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

  5. Selective Entrainment of Theta Oscillations in the Dorsal Stream Causally Enhances Auditory Working Memory Performance.

    PubMed

    Albouy, Philippe; Weiss, Aurélien; Baillet, Sylvain; Zatorre, Robert J

    2017-04-05

    The implication of the dorsal stream in manipulating auditory information in working memory has been recently established. However, the oscillatory dynamics within this network and its causal relationship with behavior remain undefined. Using simultaneous MEG/EEG, we show that theta oscillations in the dorsal stream predict participants' manipulation abilities during memory retention in a task requiring the comparison of two patterns differing in temporal order. We investigated the causal relationship between brain oscillations and behavior by applying theta-rhythmic TMS combined with EEG over the MEG-identified target (left intraparietal sulcus) during the silent interval between the two stimuli. Rhythmic TMS entrained theta oscillation and boosted participants' accuracy. TMS-induced oscillatory entrainment scaled with behavioral enhancement, and both gains varied with participants' baseline abilities. These effects were not seen for a melody-comparison control task and were not observed for arrhythmic TMS. These data establish theta activity in the dorsal stream as causally related to memory manipulation. VIDEO ABSTRACT.

  6. Mechanisms of Theta Plasmid Replication.

    PubMed

    Lilly, Joshua; Camps, Manel

    2015-02-01

    Plasmids are autonomously replicating pieces of DNA. This article discusses theta plasmid replication, which is a class of circular plasmid replication that includes ColE1-like origins of replication popular with expression vectors. All modalities of theta plasmid replication initiate synthesis with the leading strand at a predetermined site and complete replication through recruitment of the host's replisome, which extends the leading strand continuously while synthesizing the lagging strand discontinuously. There are clear differences between different modalities of theta plasmid replication in mechanisms of DNA duplex melting and in priming of leading- and lagging-strand synthesis. In some replicons duplex melting depends on transcription, while other replicons rely on plasmid-encoded trans-acting proteins (Reps); primers for leading-strand synthesis can be generated through processing of a transcript or in other replicons by the action of host- or plasmid-encoded primases. None of these processes require DNA breaks. The frequency of replication initiation is tightly regulated to facilitate establishment in permissive hosts and to achieve a steady state. The last section of the article reviews how plasmid copy number is sensed and how this feedback modulates the frequency of replication.

  7. Transient ischemic attacks: electrophysiological (conventional and topographic EEG) and radiological (CCT) evaluation.

    PubMed

    Madkour, O; Elwan, O; Hamdy, H; Elwan, H; Abbas, A; Taher, M; Abdel-Kader, A

    1993-10-01

    The value of electrophysiological tests: conventional electroencephalography (EEG), topographic EEG analysis as well as computerized tomography (CT) in the diagnosis and evaluation of 25 patients with manifestations of transient ischemic attacks (TIA) in the domain of the carotid system was assessed. Normal CT was the rule in TIA patients except in 8% of the cases, where nonspecific changes of brain atrophy were described. Conventional EEG, topographic EEG and spectral analysis could detect abnormalities in 48%, 80% and 64% of TIA cases respectively. None of the abnormal EEG records could be missed by topographic EEG analysis. 32% of the records were diagnosed as abnormal by topographic EEG, while conventional EEG failed to detect abnormalities. Spectral analysis of the EEG results revealed a significant decrease regarding mean high limit alpha percent power, and a significant increase regarding mean low and high limit theta percent power, as well as a significant increase of the mean high limit of the slow activities (delta + theta)/fast activities (alpha + beta) percent power ratio in the TIA group as compared to the normal control group.

  8. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze.

    PubMed

    Hernández-Pérez, J Jesús; Gutiérrez-Guzmán, Blanca E; López-Vázquez, Miguel Á; Olvera-Cortés, María E

    2015-01-01

    Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in

  9. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze

    PubMed Central

    Hernández-Pérez, J. Jesús; Gutiérrez-Guzmán, Blanca E.; López-Vázquez, Miguel Á.; Olvera-Cortés, María E.

    2015-01-01

    Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in

  10. Electroencephalogram (EEG) (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old EEG (Electroencephalogram) KidsHealth > For Parents > EEG (Electroencephalogram) A A A What's in this article? ... Child If You Have Questions en español Electroencefalograma (EEG) What It Is An electroencephalogram (EEG) is a ...

  11. Electroencephalogram (EEG) (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old EEG (Electroencephalogram) KidsHealth > For Parents > EEG (Electroencephalogram) Print A A A What's in this ... Child If You Have Questions en español Electroencefalograma (EEG) What It Is An electroencephalogram (EEG) is a ...

  12. Low-frequency theta oscillations in the human hippocampus during real-world and virtual navigation.

    PubMed

    Bohbot, Véronique D; Copara, Milagros S; Gotman, Jean; Ekstrom, Arne D

    2017-02-14

    Low-Frequency Oscillations (LFO) in the range of 7-9 Hz, or theta rhythm, has been recorded in rodents ambulating in the real world. However, intra-hippocampus EEG recordings during virtual navigation in humans have consistently reported LFO that appear to predominate around 3-4 Hz. Here we report clear evidence of 7-9 Hz rhythmicity in raw intra-hippocampus EEG traces during real as well as virtual movement. Oscillations typically occur at a lower frequency in virtual than real world navigation. This study highlights the possibility that human and rodent hippocampal EEG activity are not as different as previously reported and this difference may arise, in part, due to the lack of actual movement in previous human navigation studies, which were virtual.

  13. Low-frequency theta oscillations in the human hippocampus during real-world and virtual navigation

    PubMed Central

    Bohbot, Véronique D.; Copara, Milagros S.; Gotman, Jean; Ekstrom, Arne D.

    2017-01-01

    Low-Frequency Oscillations (LFO) in the range of 7–9 Hz, or theta rhythm, has been recorded in rodents ambulating in the real world. However, intra-hippocampus EEG recordings during virtual navigation in humans have consistently reported LFO that appear to predominate around 3–4 Hz. Here we report clear evidence of 7–9 Hz rhythmicity in raw intra-hippocampus EEG traces during real as well as virtual movement. Oscillations typically occur at a lower frequency in virtual than real world navigation. This study highlights the possibility that human and rodent hippocampal EEG activity are not as different as previously reported and this difference may arise, in part, due to the lack of actual movement in previous human navigation studies, which were virtual. PMID:28195129

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

    PubMed

    Jackson, Alice F; Bolger, Donald J

    2014-11-01

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

  15. 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.

  16. Computational Study of Hippocampal-Septal Theta Rhythm Changes Due to Beta-Amyloid-Altered Ionic Channels

    PubMed Central

    Zou, Xin; Coyle, Damien; Wong-Lin, KongFatt; Maguire, Liam

    2011-01-01

    Electroencephagraphy (EEG) of many dementia patients has been characterized by an increase in low frequency field potential oscillations. One of the characteristics of early stage Alzheimer’s disease (AD) is an increase in theta band power (4–7 Hz). However, the mechanism(s) underlying the changes in theta oscillations are still unclear. To address this issue, we investigate the theta band power changes associated with β-Amyloid (Aβ) peptide (one of the main markers of AD) using a computational model, and by mediating the toxicity of hippocampal pyramidal neurons. We use an established biophysical hippocampal CA1-medial septum network model to evaluate four ionic channels in pyramidal neurons, which were demonstrated to be affected by Aβ. They are the L-type Ca2+ channel, delayed rectifying K+ channel, A-type fast-inactivating K+ channel and large-conductance Ca2+-activated K+ channel. Our simulation results demonstrate that only the Aβ inhibited A-type fast-inactivating K+ channel can induce an increase in hippocampo-septal theta band power, while the other channels do not affect theta rhythm. We further deduce that this increased theta band power is due to enhanced synchrony of the pyramidal neurons. Our research may elucidate potential biomarkers and therapeutics for AD. Further investigation will be helpful for better understanding of AD-induced theta rhythm abnormalities and associated cognitive deficits. PMID:21720560

  17. Index of Alpha/Theta Ratio of the Electroencephalogram: A New Marker for Alzheimer’s Disease

    PubMed Central

    Schmidt, Magali T.; Kanda, Paulo A. M.; Basile, Luis F. H.; da Silva Lopes, Helder Frederico; Baratho, Regina; Demario, Jose L. C.; Jorge, Mario S.; Nardi, Antonio E.; Machado, Sergio; Ianof, Jéssica N.; Nitrini, Ricardo; Anghinah, Renato

    2013-01-01

    Objective: We evaluated quantitative EEG measures to determine a screening index to discriminate Alzheimer’s disease (AD) patients from normal individuals. Methods: Two groups of individuals older than 50 years, comprising a control group of 57 normal volunteers and a study group of 50 patients with probable AD, were compared. EEG recordings were obtained from subjects in a wake state with eyes closed at rest for 30 min. Logistic regression analysis was conducted. Results: Spectral potentials of the alpha and theta bands were computed for all electrodes and the alpha/theta ratio calculated. Logistic regression of alpha/theta of the mean potential of the C3 and O1 electrodes was carried out. A formula was calculated to aid the diagnosis of AD yielding 76.4% sensitivity and 84.6% specificity for AD with an area under the ROC curve of 0.92. Conclusion: Logistic regression of alpha/theta of the spectrum of the mean potential of EEG represents a good marker discriminating AD patients from normal controls. PMID:24130529

  18. Mathematically gifted adolescents mobilize enhanced workspace configuration of theta cortical network during deductive reasoning.

    PubMed

    Zhang, L; Gan, J Q; Wang, H

    2015-03-19

    Previous studies have established the importance of the fronto-parietal brain network in the information processing of reasoning. At the level of cortical source analysis, this eletroencepalogram (EEG) study investigates the functional reorganization of the theta-band (4-8Hz) neurocognitive network of mathematically gifted adolescents during deductive reasoning. Depending on the dense increase of long-range phase synchronizations in the reasoning process, math-gifted adolescents show more significant adaptive reorganization and enhanced "workspace" configuration in the theta network as compared with average-ability control subjects. The salient areas are mainly located in the anterior cortical vertices of the fronto-parietal network. Further correlation analyses have shown that the enhanced workspace configuration with respect to the global topological metrics of the theta network in math-gifted subjects is correlated with the intensive frontal midline theta (fm theta) response that is related to strong neural effort for cognitive events. These results suggest that by investing more cognitive resources math-gifted adolescents temporally mobilize an enhanced task-related global neuronal workspace, which is manifested as a highly integrated fronto-parietal information processing network during the reasoning process.

  19. Clinical and imaging correlates of EEG patterns in hospitalized patients with encephalopathy.

    PubMed

    Sutter, Raoul; Stevens, Robert D; Kaplan, Peter W

    2013-04-01

    To identify the relationship between pathologic electroencephalographic (EEG) patterns, clinical and neuroradiological abnormalities, and outcome in hospitalized patients with acute encephalopathy. This 5-year cohort study was performed at an academic tertiary care center. EEGs in 154 patients with altered mental status were classified according to five predefined patterns: Isolated continuous slowing of background activity (theta, theta/delta, and delta activity) and patterns with slowing background activity with episodic transients [i.e., triphasic waves (TWs) or frontal intermittent delta activity (FIRDA)]. Clinical characteristics, blood tests and neuroimaging were compared among groups. Associations between EEG patterns and structural and non-structural abnormalities were calculated. Glasgow Outcome Score >3 at discharge was defined as favorable and 1-3 as unfavorable outcome. In multivariable analyses, theta was associated with brain atrophy (OR 2.6, p = 0.020), theta/delta with intracerebral hemorrhages (OR 6.8, p = 0.005), FIRDA with past cerebrovascular accidents (OR 2.7, p = 0.004), TWs with liver or multi-organ failure (OR 6, p = 0.004; OR 4, p = 0.039), and delta activity with alcohol/drug abuse with or without intoxication, and HIV infection (OR 3.8, p = 0.003; OR 9, p = 0.004). TWs were associated with death (OR 4.5, p = 0.005); theta/delta with unfavorable outcomes (OR 2.5, p = 0.033), while patients with FIRDA had favorable outcomes (OR 4.8, p = 0.004). In encephalopathic patients, well-defined EEG patterns are associated with specific pathological conditions and outcomes, suggesting that mechanistic hypotheses underlie these abnormal EEG patterns. To clarify the respective contributions of non-structural and structural abnormalities to encephalopathy reflected in specific EEG patterns, prospective studies using continuous EEG monitoring during the acute onset of encephalopathy are needed.

  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. Local Experience-Dependent Changes in the Wake EEG after Prolonged Wakefulness

    PubMed Central

    Hung, Ching-Sui; Sarasso, Simone; Ferrarelli, Fabio; Riedner, Brady; Ghilardi, M. Felice; Cirelli, Chiara; Tononi, Giulio

    2013-01-01

    Study Objectives: Prolonged wakefulness leads to a progressive increase in sleep pressure, reflected in a global increase in slow wave activity (SWA, 0.5-4.5 Hz) in the sleep electroencephalogram (EEG). A global increase in wake theta activity (5-9 Hz) also occurs. Recently, it was shown that prolonged wakefulness in rodents leads to signs of “local sleep” in an otherwise awake brain, accompanied by a slow/theta wave (2-6 Hz) in the local EEG that occurs at different times in different cortical areas. Compelling evidence in animals and humans also indicates that sleep is locally regulated by the amount of experience-dependent plasticity. Here, we asked whether the extended practice of tasks that involve specific brain circuits results in increased occurrence of local intermittent theta waves in the human EEG, above and beyond the global EEG changes previously described. Design: Participants recorded with high-density EEG completed 2 experiments during which they stayed awake ≥ 24 h practicing a language task (audiobook listening [AB]) or a visuomotor task (driving simulator [DS]). Setting: Sleep laboratory. Patients or Participants: 16 healthy participants (7 females). Interventions: Two extended wake periods. Measurements and Results: Both conditions resulted in global increases in resting wake EEG theta power at the end of 24 h of wake, accompanied by increased sleepiness. Moreover, wake theta power as well as the occurrence and amplitude of theta waves showed regional, task-dependent changes, increasing more over left frontal derivations in AB, and over posterior parietal regions in DS. These local changes in wake theta power correlated with similar local changes in sleep low frequencies including SWA. Conclusions: Extended experience-dependent plasticity of specific circuits results in a local increase of the wake theta EEG power in those regions, followed by more intense sleep, as reflected by SWA, over the same areas. Citation: Hung CS; Sarasso S

  2. EEG based image encryption via quantum walks.

    PubMed

    Rawat, N; Shin, Y; Balasingham, I

    2016-08-01

    An electroencephalogram (EEG) based image encryption combined with Quantum walks (QW) is encoded in Fresnel domain. The computational version of EEG randomizes the original plaintext whereas QW can serve as an excellent key generator due to its inherent nonlinear chaotic dynamic behavior. First, a spatially coherent monochromatic laser beam passes through an SLM, which introduces an arbitrary EEG phase-only mask. The modified beam is collected by a CCD. Further, the intensity is multiply with the QW digitally. EEG shows high sensitivity to system parameters and capable of encrypting and transmitting the data whereas QW has unpredictability, stability and non-periodicity. Only applying the correct keys, the original image can be retrieved successfully. Simulations and comparisons show the proposed method to be secure enough for image encryption and outperforms prior works. The proposed method opens the door towards introducing EEG and quantum computation into image encryption and promotes the convergence between our approach and image processing.

  3. Intrinsic Cornu Ammonis Area 1 Theta-Nested Gamma Oscillations Induced by Optogenetic Theta Frequency Stimulation

    PubMed Central

    Butler, James L.; Mendonça, Philipe R. F.; Robinson, Hugh P. C.

    2016-01-01

    Gamma oscillations (30–120 Hz) are thought to be important for various cognitive functions, including perception and working memory, and disruption of these oscillations has been implicated in brain disorders, such as schizophrenia and Alzheimer's disease. The cornu ammonis area 1 (CA1) of the hippocampus receives gamma frequency inputs from upstream regions (cornu ammonis area 3 and medial entorhinal cortex) and generates itself a faster gamma oscillation. The exact nature and origin of the intrinsic CA1 gamma oscillation is still under debate. Here, we expressed channelrhodopsin-2 under the CaMKIIα promoter in mice and prepared hippocampal slices to produce a model of intrinsic CA1 gamma oscillations. Sinusoidal optical stimulation of CA1 at theta frequency was found to induce robust theta-nested gamma oscillations with a temporal and spatial profile similar to CA1 gamma in vivo. The results suggest the presence of a single gamma rhythm generator with a frequency range of 65–75 Hz at 32°C. Pharmacological analysis found that the oscillations depended on both AMPA and GABAA receptors. Cell-attached and whole-cell recordings revealed that excitatory neuron firing slightly preceded interneuron firing within each gamma cycle, suggesting that this intrinsic CA1 gamma oscillation is generated with a pyramidal–interneuron circuit mechanism. SIGNIFICANCE STATEMENT This study demonstrates that the cornu ammonis area 1 (CA1) is capable of generating intrinsic gamma oscillations in response to theta input. This gamma generator is independent of activity in the upstream regions, highlighting that CA1 can produce its own gamma oscillation in addition to inheriting activity from the upstream regions. This supports the theory that gamma oscillations predominantly function to achieve local synchrony, and that a local gamma generated in each area conducts the signal to the downstream region. PMID:27076416

  4. Effect of diazepam on EEG power and coherent activity: sex differences.

    PubMed

    Romano-Torres, M; Borja-Lascurain, E; Chao-Rebolledo, C; del-Río-Portilla, Y; Corsi-Cabrera, M

    2002-10-01

    Benzodiazepine-steroid interactions and sex differences in brain and circulating levels of gonadal steroids, lead to hypothesized differential effects of DZ on EEG in women and men. Coherent activity has been shown to be relevant for binding information into global percepts therefore diazepam effects on EEG correlation and sex differences were assessed in a double-blind crossover study. Healthy males (9) and females (9) received a single-dose (5 mg) of diazepam or placebo. EEG was recorded with eyes open (FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2) before and 2 h after drug administration in two counterbalanced sessions. DZ selectively increased delta and theta EEG correlation among frontal regions and decreased it between right parieto-occipital (theta) and fronto-central regions (alpha2) in addition to an increase in beta2 interhemispheric correlation in men and women. Men showed increased beta1 interhemispheric correlation, decreased alpha1 and increased beta power; women showed in addition, decreased theta and alpha2 power. theta rhythm was more sensitive to DZ in women, whereas interhemispheric correlation was more affected in men. DZ had a sexually dimorphic effect on waking EEG and a disrupting effect on coherent activity, increasing balance among frontal regions and decreasing temporal coupling between anterior-posterior regions. These sex differences might be related to differences in brain organization and activational effects of female gonadal steroids which are higher in women than in men.

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

    PubMed

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

    2012-06-01

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

  6. Memory load and display polarity in visual search performance and EEG response.

    PubMed

    Chan, Tam; Hsu, Hsin-Yi

    2010-02-01

    Electroencephalogram measures have frequently been shown to be highly sensitive to variations in task conditions; however, research on the effects of memory load on EEG response and Visual Display Terminal (VDT) performance is lacking. Data from 19 college students were analyzed for effects of memory load and polarity on VDT performance. Included also were modulation of the EEG distribution around the cerebrum, the inferred source of operation of working memory and comprehension. Analyses indicated that the effects of memory load on finish time were statistically significant. The theta band at FP1 and FP2 had larger change in power than at T6, showing a large effect between memory load and frontal lobe function. This experiment on polarity and EEG response indicated the power change in the theta band was stronger for positive contrast than negative; however, the polarity of the display had no statistically significant effect on EEG response.

  7. Coupling between Theta Oscillations and Cognitive Control Network during Cross-Modal Visual and Auditory Attention: Supramodal vs Modality-Specific Mechanisms

    PubMed Central

    Wang, Wuyi; Viswanathan, Shivakumar; Lee, Taraz; Grafton, Scott T.

    2016-01-01

    Cortical theta band oscillations (4–8 Hz) in EEG signals have been shown to be important for a variety of different cognitive control operations in visual attention paradigms. However the synchronization source of these signals as defined by fMRI BOLD activity and the extent to which theta oscillations play a role in multimodal attention remains unknown. Here we investigated the extent to which cross-modal visual and auditory attention impacts theta oscillations. Using a simultaneous EEG-fMRI paradigm, healthy human participants performed an attentional vigilance task with six cross-modal conditions using naturalistic stimuli. To assess supramodal mechanisms, modulation of theta oscillation amplitude for attention to either visual or auditory stimuli was correlated with BOLD activity by conjunction analysis. Negative correlation was localized to cortical regions associated with the default mode network and positively with ventral premotor areas. Modality-associated attention to visual stimuli was marked by a positive correlation of theta and BOLD activity in fronto-parietal area that was not observed in the auditory condition. A positive correlation of theta and BOLD activity was observed in auditory cortex, while a negative correlation of theta and BOLD activity was observed in visual cortex during auditory attention. The data support a supramodal interaction of theta activity with of DMN function, and modality-associated processes within fronto-parietal networks related to top-down theta related cognitive control in cross-modal visual attention. On the other hand, in sensory cortices there are opposing effects of theta activity during cross-modal auditory attention. PMID:27391013

  8. EEG manifestations of nondual experiences in meditators.

    PubMed

    Berman, Amanda E; Stevens, Larry

    2015-01-01

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

  9. Prognostic value of EEG in different etiological types of coma.

    PubMed

    Khaburzania, M; Beridze, M

    2013-06-01

    Study aimed at evaluation of prognostic value of standard EEG in different etiology of coma and the influence of etiological factor on the EEG patterns and coma outcome. Totally 175 coma patients were investigated. Patients were evaluated by Glasgow Coma Scale (GCS), clinically and by 16 channel electroencephalography. Auditory evoked potentials studied by EEG -regime for evoked potentials in patients with vegetative state (VS). Patients divided in 8 groups according to coma etiology. All patients were studied for photoreaction, brainstem reflexes, localization of sound and pain, length of coma state and outcome. Brain injury visualized by conventional CT. Outcome defined as death, VS, recovery with disability and without disability. Disability was rated by Disability Rating Scale (DRS). Recovered patients assessed by Mini Mental State Examination (MMSE) scale. Statistics performed by SPSS-11.0. From 175 coma patients 55 patients died, 23 patients found in VS, 97 patients recovered with and without disability. In all etiological groups of coma the background EEG patterns were established. Correspondence analysis of all investigated factors revealed that sound localization had the significant association with EEG delta and theta rhythms and with recovery from coma state (Chi-sqr. =31.10493; p= 0.000001). Among 23 VS patients 9 patients had the signs of MCS and showed the long latency waves (p300) after binaural stimulation. The high amplitude theta frequencies in frontal and temporal lobes significantly correlated with prolongation of latency of cognitive evoked potentials (r=+0.47; p<0.01). Etiological factor had the significant effect on EEG patterns' association with coma outcome only in hemorrhagic and traumatic coma (chi-sqr.=12.95; p<0.005; chi-sqr.=7.92; p<0.03 respectively). Significant correlations established between the delta and theta EEG patterns and coma outcome. Low amplitude decreased power delta and theta frequencies correlated with SND in survived

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

    PubMed

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

    2013-09-01

    This study investigated sex differences between the EEGs of Combined and Inattentive types of attention-deficit/hyperactivity disorder (AD/HD) within boys and girls aged 8-12 years. Subject groups included 80 AD/HD Combined type (40 boys and 40 girls), 80 AD/HD Inattentive type (40 boys and 40 girls) and 80 controls (40 boys and 40 girls). An eyes-closed resting EEG was recorded and Fourier transformed to provide estimates for absolute and relative power in the delta, theta, alpha and beta frequency bands, as well as total power and the theta/beta ratio. The boy AD/HD groups, compared with boy controls, had greater absolute and relative theta, greater theta/beta ratio, reduced absolute and relative alpha, and reduced absolute and relative beta. The girl AD/HD groups, compared with girl controls, had greater absolute delta, greater absolute and relative theta, greater theta/beta ratio, greater total power, and reduced relative delta and relative beta. Between AD/HD types, Combined type boys had globally greater absolute and relative theta, greater theta/beta ratio, and less relative alpha than Inattentive type boys. While topographical differences emerged, there were no significant global differences between AD/HD types in girls. That is, EEG differences between AD/HD types are dissimilar in boys and girls. Different EEG maturational patterns between boys and girls also obscure AD/HD-related EEG abnormalities. These results have important implications for our understanding of AD/HD in girls. Ignoring such sex differences may have compromised the value of previous AD/HD investigations, and these sex differences should be recognised in future research.

  11. EEG coherence: topography and frequency structure.

    PubMed

    Chorlian, David Balin; Rangaswamy, Madhavi; Porjesz, Bernice

    2009-09-01

    Topographical patterns of bipolar EEG coherence are frequency specific, indicating the presence of diverse neuroanatomical and neurophysiological factors in EEG production. Bipolar EEG coherence values were calculated at 50 frequency bins ranging from 3 to 28 Hz for 39 coherence pairs. Data were derived from 4.25 min of resting EEG obtained from 106 healthy adult male subjects and analyzed in 0.5 Hz bins by Fourier transform methods. Frequency bands were clearly separated at 8.5 and 13 Hz, with a less distinct separations at 6 and 20 Hz. Within pair (non-topographic) and across pair (topographic), measures gave similar patterns of separation. Significant pathways were primarily anterior-posterior interhemispheric or perpendicular to the anterior-posterior axis. There was little difference between left and right for comparable pairs. Theta band coherent activity involves distinct midline and temporal sources, with temporal sources showing anterior/posterior differentiation. In contrast, alpha activity has a distinct posterior focus, while beta activity shows no clear global structure. A spatially homogeneous model based on characteristics of thalamocortical connectivity accounts for much of the data, but departures from the model indicate the contribution of other neural factors to coherence.

  12. 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.

  13. EEG and ERP assessment of normal aging.

    PubMed

    Polich, J

    1997-05-01

    EEG was recorded from 120 normal adult subjects who ranged in age from 20 to 80+ years in separate eyes open/closed conditions. The P3(00) event-related brain potential (ERP) was elicited with auditory and visual stimuli in separate conditions in the same subjects. Spectral analysis indicated that overall EEG power decreased as subject age increased. P3 amplitude decreased and peak latency increased for both the auditory and visual stimulus conditions as subject age increased. Few age-related differences were observed for the N1, P2, or N2 components. Spectral power from the delta, theta, and alpha bands correlated positively with P3 amplitude across subject age, but mean band frequency demonstrated only weak associations with P3 latency. No strong relationships were found between EEG and the other ERP component variables. The results suggest that age contributes to EEG power shifts, and that such changes significantly affect age-related variability of the P3 ERP component.

  14. The effect of a single session of short duration heart rate variability biofeedback on EEG: a pilot study.

    PubMed

    Prinsloo, Gabriell E; Rauch, H G Laurie; Karpul, David; Derman, Wayne E

    2013-03-01

    This pilot study examines the effect of heart rate variability (HRV) biofeedback on measures of electroencephalogram (EEG) during and immediately after biofeedback. Eighteen healthy males exposed to work-related stress, were randomised into an HRV biofeedback (BIO) or a comparative group (COM). EEG was recorded during the intervention and during rest periods before and after the intervention. Power spectral density in theta, alpha and beta frequency bands and theta/beta ratios were calculated. During the intervention, the BIO group had higher relative theta power [Fz and Pz (p < 0.01), Cz (p < 0.05)], lower fronto-central relative beta power (p < 0.05), and higher theta/beta [Fz and Cz (p < 0.01), Pz (p < 0.05)] than the COM group. The groups showed different responses after the intervention with increased posterior theta/beta (p < 0.05) in the BIO group and altered posterior relative theta (p < 0.05), central relative beta (p = 0.06) and central-posterior theta/beta (p < 0.01) in the post-intervention rest period. The findings of this study suggest that a single session of HRV biofeedback after a single training session was associated with changes in EEG suggestive of increased internal attention and relaxation both during and after the intervention. However, the comparative intervention was associated with changes suggestive of increased mental effort and possible anxiety during and after the intervention.

  15. A Comparison of Frontal Theta Activity During Shooting among Biathletes and Cross-Country Skiers before and after Vigorous Exercise

    PubMed Central

    Luchsinger, Harri; Sandbakk, Øyvind; Schubert, Michael; Ettema, Gertjan; Baumeister, Jochen

    2016-01-01

    Background Previous studies using electroencephalography (EEG) to monitor brain activity have linked higher frontal theta activity to more focused attention and superior performance in goal-directed precision tasks. In biathlon, shooting performance requires focused attention after high-intensity cross-country skiing. Purpose To compare biathletes (serving as experts) and cross-country skiers (novices) and examine the effect of vigorous exercise on frontal theta activity during shooting. Methods EEG frontal theta (4–7 Hz) activity was compared between nine biathletes and eight cross-country skiers at comparable skiing performance levels who fired 100 shots on a 5-m indoor shooting range in quiescent condition followed by 20 shots after each of five 6-min high-intensity roller skiing sessions in the skating technique on a treadmill. Results Biathletes hit 80±14% and 81±10% before and after the roller skiing sessions, respectively. For the cross-country skiers these values were significantly lower than for the biathletes and amounted to 39±13% and 44±11% (p<0.01). Biathletes had on average 6% higher frontal theta activity during shooting as compared to cross-country skiers (F1,15 = 4.82, p = 0.044), but no significant effect of vigorous exercise on frontal theta activity in either of the two groups were found (F1,15 = 0.14, p = 0.72). Conclusions Biathletes had significantly higher frontal theta activity than cross-country skiers during shooting, indicating higher focused attention in biathletes. Vigorous exercise did not decrease shooting performance or frontal theta activity during shooting in biathletes and cross-country skiers. PMID:26981639

  16. Photographic observations of Theta-1 Orionis

    NASA Technical Reports Server (NTRS)

    Feibelman, W. A.; Gull, T. R.

    1979-01-01

    Photographic observations of the eclipsing binary Theta-1 Ori A suggest a secondary minimum near phase 0.64 of its 65.43233-day period. This minimum may be wavelength dependent. The star Theta-1 Ori E is suspected of being variable.

  17. 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.

  18. Concurrent working memory task decreases the Stroop interference effect as indexed by the decreased theta oscillations.

    PubMed

    Zhao, Y; Tang, D; Hu, L; Zhang, L; Hitchman, G; Wang, L; Chen, A

    2014-03-14

    Working memory (WM) tasks may increase or decrease the interference effect of concurrently performed cognitive control tasks. However, the neural oscillatory correlates of this modulation effect of WM on the Stroop task are still largely unknown. In the present study, behavioral and electroencephalographic (EEG) data were recorded from 32 healthy participants during their performance of the single Stroop task and the same task with a concurrent WM task. We observed that the Stroop interference effect represented in both response times (RTs) and theta-band event-related spectral perturbation (ERSP) magnitude reduced under the dual-task condition compared with the single-task condition. The reduction of interference in theta-band ERSP was further positively correlated with interference reduction in RTs, and was mainly explained by the source in the left middle frontal gyrus. In conclusion, the present study suggests that the effect of concurrent WM tasks on the reduction of the Stroop interference effect can be indexed by EEG oscillations in theta-band rhythm in the centro-frontal regions and this modulation was mediated by the reduced cognitive control under the concurrent WM task.

  19. Grid cells and theta as oscillatory interference: electrophysiological data from freely moving rats.

    PubMed

    Jeewajee, A; Barry, C; O'Keefe, J; Burgess, N

    2008-01-01

    The oscillatory interference model (Burgess et al. (2007) Hippocampus 17:801-812) explains the generation of spatially stable, regular firing patterns by medial entorhinal cortical (mEC) grid cells in terms of the interference between velocity-controlled oscillators (VCOs) with different preferred directions. This model predicts specific relationships between the intrinsic firing frequency and spatial scale of grid cell firing, the EEG theta frequency, and running speed (Burgess,2008). Here, we use spectral analyses of EEG and of spike autocorrelograms to estimate the intrinsic firing frequency of grid cells, and the concurrent theta frequency, in mEC Layer II in freely moving rats. The intrinsic firing frequency of grid cells increased with running speed and decreased with grid scale, according to the quantitative prediction of the model. Similarly, theta frequency increased with running speed, which was also predicted by the model. An alternative Moiré interference model (Blair et al.,2007) predicts a direction-dependent variation in intrinsic firing frequency, which was not found. Our results suggest that interference between VCOs generates the spatial firing patterns of entorhinal grid cells according to the oscillatory interference model. They also provide specific constraints on this model of grid cell firing and have more general implications for viewing neuronal processing in terms of interfering oscillatory processes.

  20. Wavelet entropy analysis of event-related potentials indicates modality-independent theta dominance.

    PubMed

    Yordanova, Juliana; Kolev, Vasil; Rosso, Osvaldo A; Schürmann, Martin; Sakowitz, Oliver W; Ozgören, Murat; Basar, Erol

    2002-05-30

    Sensory/cognitive stimulation elicits multiple electroencephalogram (EEG)-oscillations that may be partly or fully overlapping over the time axis. To evaluate co-existent multi-frequency oscillations, EEG responses to unimodal (auditory or visual) and bimodal (combined auditory and visual) stimuli were analyzed by applying a new method called wavelet entropy (WE). The method is based on the wavelet transform (WT) and quantifies entropy of short segments of the event-related brain potentials (ERPs). For each modality, a significant transient decrease of WE emerged in the post-stimulus EEG epoch indicating a highly-ordered state in the ERP. WE minimum was always determined by a prominent dominance of theta (4-8 Hz) ERP components over other frequency bands. Event-related 'transition to order' was most pronounced and stable at anterior electrodes, and after bimodal stimulation. Being consistently observed across different modalities, a transient theta-dominated state may reflect a processing stage that is obligatory for stimulus evaluation, during which interfering activations from other frequency networks are minimized.

  1. Prediction of subjective ratings of emotional pictures by EEG features

    NASA Astrophysics Data System (ADS)

    McFarland, Dennis J.; Parvaz, Muhammad A.; Sarnacki, William A.; Goldstein, Rita Z.; Wolpaw, Jonathan R.

    2017-02-01

    Objective. Emotion dysregulation is an important aspect of many psychiatric disorders. Brain-computer interface (BCI) technology could be a powerful new approach to facilitating therapeutic self-regulation of emotions. One possible BCI method would be to provide stimulus-specific feedback based on subject-specific electroencephalographic (EEG) responses to emotion-eliciting stimuli. Approach. To assess the feasibility of this approach, we studied the relationships between emotional valence/arousal and three EEG features: amplitude of alpha activity over frontal cortex; amplitude of theta activity over frontal midline cortex; and the late positive potential over central and posterior mid-line areas. For each feature, we evaluated its ability to predict emotional valence/arousal on both an individual and a group basis. Twenty healthy participants (9 men, 11 women; ages 22-68) rated each of 192 pictures from the IAPS collection in terms of valence and arousal twice (96 pictures on each of 4 d over 2 weeks). EEG was collected simultaneously and used to develop models based on canonical correlation to predict subject-specific single-trial ratings. Separate models were evaluated for the three EEG features: frontal alpha activity; frontal midline theta; and the late positive potential. In each case, these features were used to simultaneously predict both the normed ratings and the subject-specific ratings. Main results. Models using each of the three EEG features with data from individual subjects were generally successful at predicting subjective ratings on training data, but generalization to test data was less successful. Sparse models performed better than models without regularization. Significance. The results suggest that the frontal midline theta is a better candidate than frontal alpha activity or the late positive potential for use in a BCI-based paradigm designed to modify emotional reactions.

  2. 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.

  3. Neurofeedback training aimed to improve focused attention and alertness in children with ADHD: a study of relative power of EEG rhythms using custom-made software application.

    PubMed

    Hillard, Brent; El-Baz, Ayman S; Sears, Lonnie; Tasman, Allan; Sokhadze, Estate M

    2013-07-01

    Neurofeedback is a nonpharmacological treatment for attention-deficit hyperactivity disorder (ADHD). We propose that operant conditioning of electroencephalogram (EEG) in neurofeedback training aimed to mitigate inattention and low arousal in ADHD, will be accompanied by changes in EEG bands' relative power. Patients were 18 children diagnosed with ADHD. The neurofeedback protocol ("Focus/Alertness" by Peak Achievement Trainer) has a focused attention and alertness training mode. The neurofeedback protocol provides one for Focus and one for Alertness. This does not allow for collecting information regarding changes in specific EEG bands (delta, theta, alpha, low and high beta, and gamma) power within the 2 to 45 Hz range. Quantitative EEG analysis was completed on each of twelve 25-minute-long sessions using a custom-made MatLab application to determine the relative power of each of the aforementioned EEG bands throughout each session, and from the first session to the last session. Additional statistical analysis determined significant changes in relative power within sessions (from minute 1 to minute 25) and between sessions (from session 1 to session 12). Analysis was of relative power of theta, alpha, low and high beta, theta/alpha, theta/beta, and theta/low beta and theta/high beta ratios. Additional secondary measures of patients' post-neurofeedback outcomes were assessed, using an audiovisual selective attention test (IVA + Plus) and behavioral evaluation scores from the Aberrant Behavior Checklist. Analysis of data computed in the MatLab application, determined that theta/low beta and theta/alpha ratios decreased significantly from session 1 to session 12, and from minute 1 to minute 25 within sessions. The findings regarding EEG changes resulting from brain wave self-regulation training, along with behavioral evaluations, will help elucidate neural mechanisms of neurofeedback aimed to improve focused attention and alertness in ADHD.

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

    PubMed Central

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

    2015-01-01

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

  5. Nicotine induction of theta frequency oscillations in rodent hippocampus in vitro.

    PubMed

    Lu, C B; Henderson, Z

    2010-03-10

    The hippocampus is an area important for learning and memory and exhibits prominent and behaviourally relevant theta (4-12 Hz) and gamma (30-100 Hz) frequency oscillations in vivo. Hippocampal slices produce similar types of oscillatory activity in response to bath-application of neurotransmitter receptor agonists. The medial septum diagonal band area (MS/DB) provides both a cholinergic and GABAergic projection to the hippocampus, and although it plays a major role in the generation and maintenance of the hippocampal theta rhythm in vivo, there is evidence for intrinsic theta generation mechanisms in the hippocampus, especially in area CA3. The aim of this study was to examine the role of the nicotinic receptor (nAChR) in the induction of oscillatory field activity in the in vitro preparation of the rat hippocampus. Bath-application of a low concentration of nicotine (1 muM) to transversely-cut hippocampal slices produced persistent theta-frequency oscillations in area CA3 of the hippocampus. These oscillations were reduced by both GABA(A) receptor antagonists and ionotropic glutamate receptor antagonists, indicating the involvement of local GABAergic and glutamatergic neurons in the production of the rhythmic theta activity. The nicotine-induced theta activity was inhibited by non-selective nAChR antagonists and partially by an alpha7* nAChR antagonist. The induction of theta frequency oscillations in CA3 by nicotine was mimicked alpha7* nAChR agonists but not by non-alpha7* nAChR agonists. In conclusion, theta activity in the hippocampus may be promoted by tonic stimulation of alpha7* nAChRs, possibly via selective stimulation of theta-preferring interneurons in the hippocampus that express post-synaptic alpha7* nAChRs.

  6. Signal Quality Assessment Model for Wearable EEG Sensor on Prediction of Mental Stress.

    PubMed

    Hu, Bin; Peng, Hong; Zhao, Qinglin; Hu, Bo; Majoe, Dennis; Zheng, Fang; Moore, Philip

    2015-07-01

    Electroencephalogram (EEG) plays an important role in E-healthcare systems, especially in the mental healthcare area, where constant and unobtrusive monitoring is desirable. In the context of OPTIMI project, a novel, low cost, and light weight wearable EEG sensor has been designed and produced. In order to improve the performance and reliability of EEG sensors in real-life settings, we propose a method to evaluate the quality of EEG signals, based on which users can easily adjust the connection between electrodes and their skin. Our method helps to filter invalid EEG data from personal trials in both domestic and office settings. We then apply an algorithm based on Discrete Wavelet Transformation (DWT) and Adaptive Noise Cancellation (ANC) which has been designed to remove ocular artifacts (OA) from the EEG signal. DWT is applied to obtain a reconstructed OA signal as a reference while ANC, based on recursive least squares, is used to remove the OA from the original EEG data. The newly produced sensors were tested and deployed within the OPTIMI framework for chronic stress detection. EEG nonlinear dynamics features and frontal asymmetry of theta, alpha, and beta bands have been selected as biological indicators for chronic stress, showing relative greater right anterior EEG data activity in stressful individuals. Evaluation results demonstrate that our EEG sensor and data processing algorithms have successfully addressed the requirements and challenges of a portable system for patient monitoring, as envisioned by the EU OPTIMI project.

  7. An Alpha and Theta Intensive and Short Neurofeedback Protocol for Healthy Aging Working-Memory Training

    PubMed Central

    Reis, Joana; Portugal, Ana Maria; Fernandes, Luís; Afonso, Nuno; Pereira, Mariana; Sousa, Nuno; Dias, Nuno S.

    2016-01-01

    The present study tested the effects of an intensive and short alpha and theta neurofeedback (NF) protocol in working memory (WM) performance in a healthy elder population and explored the effects of a multimodal approach, by supplementing NF with cognitive tasks. Participants were allocated to four groups: NF (N = 9); neurofeedback supplemented with cognitive training (NFCT) (N = 8); cognitive training (CT) (N = 7) and sham neurofeedback (Sham-NF) (N = 6). The intervention consisted in 30-min sessions for 8 days. The NF group presented post intervention increases of alpha and theta relative power as well as performance in the matrix rotation task. In addition, a successful up training of frontal theta showed positive correlation with an improvement of post-training alpha and a better performance in the matrix rotation task. The results presented herein suggest that an intensive and short NF protocol enables elders to learn alpha and theta self-modulation and already presents moderate improvements in cognition and basal EEG. Also, CT group showed moderate performance gains on the cognitive tasks used during the training sessions but no clear improvements on neurophysiology and behavioral measurements were observed. This study represents a first attempt to study the effects of an intensive and short NF protocol in WM performance of elders. The evidence presented here suggests that an intensive and short NF intervention could be a valid alternative for introduction of older populations to NF methodologies. PMID:27458369

  8. An Alpha and Theta Intensive and Short Neurofeedback Protocol for Healthy Aging Working-Memory Training.

    PubMed

    Reis, Joana; Portugal, Ana Maria; Fernandes, Luís; Afonso, Nuno; Pereira, Mariana; Sousa, Nuno; Dias, Nuno S

    2016-01-01

    The present study tested the effects of an intensive and short alpha and theta neurofeedback (NF) protocol in working memory (WM) performance in a healthy elder population and explored the effects of a multimodal approach, by supplementing NF with cognitive tasks. Participants were allocated to four groups: NF (N = 9); neurofeedback supplemented with cognitive training (NFCT) (N = 8); cognitive training (CT) (N = 7) and sham neurofeedback (Sham-NF) (N = 6). The intervention consisted in 30-min sessions for 8 days. The NF group presented post intervention increases of alpha and theta relative power as well as performance in the matrix rotation task. In addition, a successful up training of frontal theta showed positive correlation with an improvement of post-training alpha and a better performance in the matrix rotation task. The results presented herein suggest that an intensive and short NF protocol enables elders to learn alpha and theta self-modulation and already presents moderate improvements in cognition and basal EEG. Also, CT group showed moderate performance gains on the cognitive tasks used during the training sessions but no clear improvements on neurophysiology and behavioral measurements were observed. This study represents a first attempt to study the effects of an intensive and short NF protocol in WM performance of elders. The evidence presented here suggests that an intensive and short NF intervention could be a valid alternative for introduction of older populations to NF methodologies.

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

    PubMed

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

    2016-06-01

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

  10. Neural mechanisms of infant learning: differences in frontal theta activity during object exploration modulate subsequent object recognition

    PubMed Central

    Begus, Katarina; Southgate, Victoria; Gliga, Teodora

    2015-01-01

    Investigating learning mechanisms in infancy relies largely on behavioural measures like visual attention, which often fail to predict whether stimuli would be encoded successfully. This study explored EEG activity in the theta frequency band, previously shown to predict successful learning in adults, to directly study infants' cognitive engagement, beyond visual attention. We tested 11-month-old infants (N = 23) and demonstrated that differences in frontal theta-band oscillations, recorded during infants' object exploration, predicted differential subsequent recognition of these objects in a preferential-looking test. Given that theta activity is modulated by motivation to learn in adults, these findings set the ground for future investigation into the drivers of infant learning. PMID:26018832

  11. Genetic and Disorder-Specific Aspects of Resting State EEG Abnormalities in Schizophrenia

    PubMed Central

    Venables, Noah C.; Bernat, Edward M.; Sponheim, Scott R.

    2009-01-01

    We evaluated whether abnormal frequency composition of the resting state electroencephalogram (EEG) in schizophrenia was associated with genetic liability for the disorder by studying first-degree biological relatives of schizophrenia patients. The study included a data-driven method for defining EEG frequency components and determined the specificity of resting state EEG frequency abnormalities by assessing schizophrenia patients, bipolar disorder patients, and relatives of both patient groups. Schizophrenia patients and their relatives, but not bipolar patients or their relatives, exhibited increased high-frequency activity (beta) providing evidence for disturbances in resting state brain activity being specific to genetic liability for schizophrenia. Schizophrenia patients exhibited augmented low-frequency EEG activity (delta, theta), while bipolar disorder patients and the 2 groups of relatives generally failed to manifest similar low-frequency EEG abnormalities. The Val158Met polymorphism for the catechol-O-methyl transferase (COMT) gene was most strongly associated with delta and theta activity in schizophrenia patients. Met homozygote schizophrenia patients exhibited augmented activity for the 2 low-frequency bands compared with control subjects. Excessive high-frequency EEG activity over frontal brain regions may serve as an endophenotype that reflects cortical expression of genetic vulnerability for schizophrenia. Low-frequency resting state EEG anomalies in schizophrenia may relate to disorder-specific pathophysiology in schizophrenia and the influence of the COMT gene on tonic dopamanergic function. PMID:18381357

  12. 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.

  13. Delta and Theta oscillations as risk markers in Adolescent Offspring of Alcoholics

    PubMed Central

    Rangaswamy, Madhavi; Jones, Kevin A.; Porjesz, Bernice; Chorlian, David B.; Padmanabhapillai, Ajayan; Kamarajan, Chella; Kuperman, Samuel; Rohrbaugh, John; O’Connor, Sean J.; Bauer, Lance O.; Schuckit, Marc A.; Begleiter., Henri

    2007-01-01

    Background Visual P300 is consistently lower in alcohol dependent individuals, their offspring and subjects at risk. Delta and theta event related oscillations (ERO) are the major contributors to the P300 signal. The total and evoked power in delta and theta bands in the 300 to 700 millisecond post-stimulus window (corresponding to the zone of P3 maxima) was compared between adolescent offspring of alcoholics (high-risk) and age-matched normal controls (low-risk), to assess the utility of the risk markers. Methods EEG was recorded during the performance of visual oddball task. The S-Transform algorithm decomposed the EEG signals into different frequency bands and the group differences in total and evoked power in the oscillatory responses during the P300 time window (300 to 700 ms) were analyzed using a multivariate design. Similar analysis was performed on P300 peak amplitudes for the target. Results The high-risk group showed significantly lower parietal post-stimulus evoked and total power in the delta band for targets. A decrease in total power was seen centrally and parietally in theta band. The P300 peak amplitude in the parietal electrodes was also significantly lower in the high-risk group. Conclusions The decreased total theta power and total and evoked delta power for visual targets in high risk individuals may serve as an endophenotypic marker in the development of alcoholism and other disinhibitory disorders. The differences seen between the offspring of alcoholics and controls may have a cholinergic basis. The ERO measures appear to be more robust than the P300 amplitude in differentiating the groups. PMID:17129626

  14. Hippocampal theta sequences reflect current goals.

    PubMed

    Wikenheiser, Andrew M; Redish, A David

    2015-02-01

    Hippocampal information processing is discretized by oscillations, and the ensemble activity of place cells is organized into temporal sequences bounded by theta cycles. Theta sequences represent time-compressed trajectories through space. Their forward-directed nature makes them an intuitive candidate mechanism for planning future trajectories, but their connection to goal-directed behavior remains unclear. As rats performed a value-guided decision-making task, the extent to which theta sequences projected ahead of the animal's current location varied on a moment-by-moment basis depending on the rat's goals. Look-ahead extended farther on journeys to distant goals than on journeys to more proximal goals and was predictive of the animal's destination. On arrival at goals, however, look-ahead was similar regardless of where the animal began its journey from. Together, these results provide evidence that hippocampal theta sequences contain information related to goals or intentions, pointing toward a potential spatial basis for planning.

  15. Movement Enhances the Nonlinearity of Hippocampal Theta

    PubMed Central

    Sheremet, Alex; Burke, Sara N.

    2016-01-01

    The nonlinear, metastable dynamics of the brain are essential for large-scale integration of smaller components and for the rapid organization of neurons in support of behavior. Therefore, understanding the nonlinearity of the brain is paramount for understanding the relationship between brain dynamics and behavior. Explicit quantitative descriptions of the properties and consequences of nonlinear neural networks, however, are rare. Because the local field potential (LFP) reflects the total activity across a population of neurons, nonlinearites of the nervous system should be quantifiable by examining oscillatory structure. We used high-order spectral analysis of LFP recorded from the dorsal and intermediate regions of the rat hippocampus to show that the nonlinear character of the hippocampal theta rhythm is directly related to movement speed of the animal. In the time domain, nonlinearity is expressed as the development of skewness and asymmetry in the theta shape. In the spectral domain, nonlinear dynamics manifest as the development of a chain of harmonics statistically phase coupled to the theta oscillation. This evolution was modulated across hippocampal regions, being stronger in the dorsal CA1 relative to more intermediate areas. The intensity and timing of the spiking activity of pyramidal cells and interneurons was strongly correlated to theta nonlinearity. Because theta is known to propagate from dorsal to ventral regions of the hippocampus, these data suggest that the nonlinear character of theta decreases as it travels and supports a hypothesis that activity dissipates along the longitudinal axis of the hippocampus. SIGNIFICANCE STATEMENT We describe the first explicit quantification regarding how behavior enhances the nonlinearity of the nervous system. Our findings demonstrate uniquely how theta changes with increasing speed due to the altered underlying neuronal dynamics and open new directions of research on the relationship between single

  16. Mobile EEG in epilepsy.

    PubMed

    Askamp, Jessica; van Putten, Michel J A M

    2014-01-01

    The sensitivity of routine EEG recordings for interictal epileptiform discharges in epilepsy is limited. In some patients, inpatient video-EEG may be performed to increase the likelihood of finding abnormalities. Although many agree that home EEG recordings may provide a cost-effective alternative to these recordings, their use is still not introduced everywhere. We surveyed Dutch neurologists and patients and evaluated a novel mobile EEG device (Mobita, TMSi). Key specifications were compared with three other current mobile EEG devices. We shortly discuss algorithms to assist in the review process. Thirty percent (33 out of 109) of Dutch neurologists reported that home EEG recordings are used in their hospital. The majority of neurologists think that mobile EEG can have additional value in investigation of unclear paroxysms, but not in the initial diagnosis after a first seizure. Poor electrode contacts and signal quality, limited recording time and absence of software for reliable and effective assistance in the interpretation of EEGs have been important constraints for usage, but in recent devices discussed here, many of these problems have been solved. The majority of our patients were satisfied with the home EEG procedure and did not think that our EEG device was uncomfortable to wear, but they did feel uneasy wearing it in public.

  17. Review of neonatal EEG.

    PubMed

    Husain, Aatif M

    2005-03-01

    Neonatal electroencephalography (EEG) presents some of the most difficult challenges in EEG interpretation. It differs significantly in many ways from EEG of older children and adults. Technologically, acquisition of a neonatal EEG is significantly more difficult and different than an adult EEG. There are numerous features that are age-specific and change almost week-to-week in the preterm infant. Some features may be normal at one age and abnormal if they persist for several weeks. Many of these features also have different implications in neonates as compared to older individuals. These issues mandate a different approach to neonatal EEG interpretation. In this article an overview of neonatal EEG is presented. After a brief discussion of relevant technical issues, various normal EEG features encountered in neonates are discussed. This is followed by a discussion of the ontogeny of EEG, starting from the age of viability to the first few months of life. A description of various abnormalities follows. Finally, an approach to analysis of a neonatal EEG is presented.

  18. 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.

  19. Theta event-related synchronization is a biomarker for a morbid effect of alcoholism on the brain that may partially resolve with extended abstinence.

    PubMed

    Gilmore, Casey S; Fein, George

    2012-11-01

    Analyzing the induced (non-stimulus-phase-locked) EEG activity elicited by targets in a three-condition visual oddball task, Fein and colleagues have shown increased theta band event-related synchronization (ERS) in two different samples of long-term abstinent alcoholics (LTAA) compared with age- and gender-comparable controls. The theta ERS effect in alcoholics was also shown to be independent of, and opposite in direction to, the reduced amplitude evoked (stimulus-phase-locked) activity typically found in alcoholics and those at genetic risk of developing alcoholism. This study extends these findings by applying time-frequency analysis to target stimulus event-related EEG to compare evoked and induced theta activity in 43 LTAA and 72 nonalcoholic controls with a group of 31 alcoholics who just recently initiated abstinence from alcohol (between 6- and 15-week abstinent; referred to as short-term abstinent alcoholics, STAA). Results demonstrated that (1) evoked theta power was reduced to the same degree in STAA and LTAA compared with nonalcoholic control participants, while (2) induced theta activity, measured by theta ERS, was increased in both STAA and LTAA relative to controls, but was also increased in STAA relative to LTAA. The STAA and LTAA groups did not differ on measures of alcohol use severity or family history of alcohol problems. These results, coupled with previous findings that show a relationship between stronger theta ERS and increased memory load and attention allocation, suggest that increased theta ERS may be a biomarker for a detrimental effect of chronic alcohol abuse on the brain - a detriment that may recover, at least partially, with extended abstinence.

  20. Memories of attachment hamper EEG cortical connectivity in dissociative patients.

    PubMed

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

    2014-08-01

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

  1. Chemotherapy disrupts learning, neurogenesis and theta activity in the adult brain.

    PubMed

    Nokia, Miriam S; Anderson, Megan L; Shors, Tracey J

    2012-12-01

    Chemotherapy, especially if prolonged, disrupts attention, working memory and speed of processing in humans. Most cancer drugs that cross the blood-brain barrier also decrease adult neurogenesis. Because new neurons are generated in the hippocampus, this decrease may contribute to the deficits in working memory and related thought processes. The neurophysiological mechanisms that underlie these deficits are generally unknown. A possible mediator is hippocampal oscillatory activity within the theta range (3-12 Hz). Theta activity predicts and promotes efficient learning in healthy animals and humans. Here, we hypothesised that chemotherapy disrupts learning via decreases in hippocampal adult neurogenesis and theta activity. Temozolomide was administered to adult male Sprague-Dawley rats in a cyclic manner for several weeks. Treatment was followed by training with different types of eyeblink classical conditioning, a form of associative learning. Chemotherapy reduced both neurogenesis and endogenous theta activity, as well as disrupted learning and related theta-band responses to the conditioned stimulus. The detrimental effects of temozolomide only occurred after several weeks of treatment, and only on a task that requires the association of events across a temporal gap and not during training with temporally overlapping stimuli. Chemotherapy did not disrupt the memory for previously learned associations, a memory independent of (new neurons in) the hippocampus. In conclusion, prolonged systemic chemotherapy is associated with a decrease in hippocampal adult neurogenesis and theta activity that may explain the selective deficits in processes of learning that describe the 'chemobrain'.

  2. Power spectral analysis of hippocampal and cortical EEG activity following severe prenatal protein malnutrition in the rat.

    PubMed

    Morgane, P J; Austin, K; Siok, C; LaFrance, R; Bronzino, J D

    1985-10-01

    We have studied the effects of prenatal protein malnutrition on development of the hippocampal and frontal cortical electroencephalographic (EEG) activity. Using power spectral analyses in rats of several age groups we found that protein malnutrition, instituted prenatally and continued postnatally, produces marked alterations in power spectral measures, i.e., alterations in peak theta frequency in the hippocampus during rapid eye movement (REM) sleep. Peak theta frequency was found to be significantly retarded in malnourished animals, especially during the preweaning period of development. Protein malnutrition, therefore, appears to affect mechanisms responsible for generating the tonic component of theta activity.

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

    PubMed

    Jäncke, Lutz; Alahmadi, Nsreen

    2016-01-01

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

  4. Classification of Healthy Subjects and Alzheimer's Disease Patients with Dementia from Cortical Sources of Resting State EEG Rhythms: A Study Using Artificial Neural Networks

    PubMed Central

    Triggiani, Antonio I.; Bevilacqua, Vitoantonio; Brunetti, Antonio; Lizio, Roberta; Tattoli, Giacomo; Cassano, Fabio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Barulli, Maria R.; Tortelli, Rosanna; Cardinali, Valentina; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Stocchi, Fabrizio; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Lacidogna, Giordano; Orzi, Francesco; Buttinelli, Carla; Giubilei, Franco; Del Percio, Claudio; Frisoni, Giovanni B.; Babiloni, Claudio

    2017-01-01

    Previous evidence showed a 75.5% best accuracy in the classification of 120 Alzheimer's disease (AD) patients with dementia and 100 matched normal elderly (Nold) subjects based on cortical source current density and linear lagged connectivity estimated by eLORETA freeware from resting state eyes-closed electroencephalographic (rsEEG) rhythms (Babiloni et al., 2016a). Specifically, that accuracy was reached using the ratio between occipital delta and alpha1 current density for a linear univariate classifier (receiver operating characteristic curves). Here we tested an innovative approach based on an artificial neural network (ANN) classifier from the same database of rsEEG markers. Frequency bands of interest were delta (2–4 Hz), theta (4–8 Hz Hz), alpha1 (8–10.5 Hz), and alpha2 (10.5–13 Hz). ANN classification showed an accuracy of 77% using the most 4 discriminative rsEEG markers of source current density (parietal theta/alpha 1, temporal theta/alpha 1, occipital theta/alpha 1, and occipital delta/alpha 1). It also showed an accuracy of 72% using the most 4 discriminative rsEEG markers of source lagged linear connectivity (inter-hemispherical occipital delta/alpha 2, intra-hemispherical right parietal-limbic alpha 1, intra-hemispherical left occipital-temporal theta/alpha 1, intra-hemispherical right occipital-temporal theta/alpha 1). With these 8 markers combined, an accuracy of at least 76% was reached. Interestingly, this accuracy based on 8 (linear) rsEEG markers as inputs to ANN was similar to that obtained with a single rsEEG marker (Babiloni et al., 2016a), thus unveiling their information redundancy for classification purposes. In future AD studies, inputs to ANNs should include other classes of independent linear (i.e., directed transfer function) and non-linear (i.e., entropy) rsEEG markers to improve the classification. PMID:28184183

  5. Classification of Healthy Subjects and Alzheimer's Disease Patients with Dementia from Cortical Sources of Resting State EEG Rhythms: A Study Using Artificial Neural Networks.

    PubMed

    Triggiani, Antonio I; Bevilacqua, Vitoantonio; Brunetti, Antonio; Lizio, Roberta; Tattoli, Giacomo; Cassano, Fabio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Barulli, Maria R; Tortelli, Rosanna; Cardinali, Valentina; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Stocchi, Fabrizio; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Lacidogna, Giordano; Orzi, Francesco; Buttinelli, Carla; Giubilei, Franco; Del Percio, Claudio; Frisoni, Giovanni B; Babiloni, Claudio

    2016-01-01

    Previous evidence showed a 75.5% best accuracy in the classification of 120 Alzheimer's disease (AD) patients with dementia and 100 matched normal elderly (Nold) subjects based on cortical source current density and linear lagged connectivity estimated by eLORETA freeware from resting state eyes-closed electroencephalographic (rsEEG) rhythms (Babiloni et al., 2016a). Specifically, that accuracy was reached using the ratio between occipital delta and alpha1 current density for a linear univariate classifier (receiver operating characteristic curves). Here we tested an innovative approach based on an artificial neural network (ANN) classifier from the same database of rsEEG markers. Frequency bands of interest were delta (2-4 Hz), theta (4-8 Hz Hz), alpha1 (8-10.5 Hz), and alpha2 (10.5-13 Hz). ANN classification showed an accuracy of 77% using the most 4 discriminative rsEEG markers of source current density (parietal theta/alpha 1, temporal theta/alpha 1, occipital theta/alpha 1, and occipital delta/alpha 1). It also showed an accuracy of 72% using the most 4 discriminative rsEEG markers of source lagged linear connectivity (inter-hemispherical occipital delta/alpha 2, intra-hemispherical right parietal-limbic alpha 1, intra-hemispherical left occipital-temporal theta/alpha 1, intra-hemispherical right occipital-temporal theta/alpha 1). With these 8 markers combined, an accuracy of at least 76% was reached. Interestingly, this accuracy based on 8 (linear) rsEEG markers as inputs to ANN was similar to that obtained with a single rsEEG marker (Babiloni et al., 2016a), thus unveiling their information redundancy for classification purposes. In future AD studies, inputs to ANNs should include other classes of independent linear (i.e., directed transfer function) and non-linear (i.e., entropy) rsEEG markers to improve the classification.

  6. Extraversion and fronto-posterior EEG spectral power gradient: an independent component analysis.

    PubMed

    Knyazev, Gennady G; Bocharov, Andrey V; Pylkova, Liudmila V

    2012-02-01

    Several studies show that the fronto-posterior EEG spectral power gradient is a stable individual characteristic related to personality. Whether this characteristic is specifically related to agentic extraversion and theta band of frequencies or is associated with a broader set of personality traits and frequency bands is a matter of debate, as well as the specific cortical regions contributing to this effect. To clarify these questions, we used group independent component analysis (ICA) and source localization techniques. Agentic extraversion was associated with higher theta activity in the default mode network's (DMN) posterior hub and lower theta activity in the orbitofrontal cortex (OFC). Regression analyses showed that theta activity predicted agentic extraversion better than other frequency bands and agentic extraversion predicted posterior versus frontal activity better than other personality dimensions. These results are taken to indicate higher tonic activity in OFC and lower activity in DMN in extraverts as compared to introverts.

  7. EEG and Coma.

    PubMed

    Ardeshna, Nikesh I

    2016-03-01

    Coma is defined as a state of extreme unresponsiveness, in which a person exhibits no voluntary movement or behavior even to painful stimuli. The utilization of EEG for patients in coma has increased dramatically over the last few years. In fact, many institutions have set protocols for continuous EEG (cEEG) monitoring for patients in coma due to potential causes such as subarachnoid hemorrhage or cardiac arrest. Consequently, EEG plays an important role in diagnosis, managenent, and in some cases even prognosis of coma patients.

  8. 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

  9. 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.

  10. 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.

  11. Connectivity Measures in EEG Microstructural Sleep Elements

    PubMed Central

    Sakellariou, Dimitris; Koupparis, Andreas M.; Kokkinos, Vasileios; Koutroumanidis, Michalis; Kostopoulos, George K.

    2016-01-01

    During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting procedures. The connectivity patterns of the latter, among other aspects of sleep microstructure, are still to be fully elucidated. We suggest here a methodology for the assessment and investigation of the connectivity patterns of EEG microstructural elements, such as sleep spindles. The methodology combines techniques in the preprocessing, estimation, error assessing and visualization of results levels in order to allow the detailed examination of the connectivity aspects (levels and directionality of information flow) over frequency and time with notable resolution, while dealing with the volume conduction and EEG reference assessment. The high temporal and frequency resolution of the methodology will allow the association between the microelements and the dynamically forming networks that characterize them, and consequently possibly reveal aspects of the EEG microstructure. The proposed methodology is initially tested on artificially generated signals for proof of concept and subsequently applied to real EEG recordings via a custom built MATLAB-based tool developed for such studies. Preliminary results from 843 fast sleep spindles recorded in whole night sleep of 5 healthy volunteers indicate a prevailing pattern of interactions between centroparietal and frontal regions. We demonstrate hereby, an opening to our knowledge attempt to estimate the scalp EEG connectivity that characterizes fast sleep spindles via an “EEG-element connectivity” methodology we propose. The application of the latter, via a computational tool we developed suggests it is able to investigate the connectivity patterns related to the

  12. An EEG Finger-Print of fMRI deep regional activation.

    PubMed

    Meir-Hasson, Yehudit; Kinreich, Sivan; Podlipsky, Ilana; Hendler, Talma; Intrator, Nathan

    2014-11-15

    This work introduces a general framework for producing an EEG Finger-Print (EFP) which can be used to predict specific brain activity as measured by fMRI at a given deep region. This new approach allows for improved EEG spatial resolution based on simultaneous fMRI activity measurements. Advanced signal processing and machine learning methods were applied on EEG data acquired simultaneously with fMRI during relaxation training guided by on-line continuous feedback on changing alpha/theta EEG measure. We focused on demonstrating improved EEG prediction of activation in sub-cortical regions such as the amygdala. Our analysis shows that a ridge regression model that is based on time/frequency representation of EEG data from a single electrode, can predict the amygdala related activity significantly better than a traditional theta/alpha activity sampled from the best electrode and about 1/3 of the times, significantly better than a linear combination of frequencies with a pre-defined delay. The far-reaching goal of our approach is to be able to reduce the need for fMRI scanning for probing specific sub-cortical regions such as the amygdala as the basis for brain-training procedures. On the other hand, activity in those regions can be characterized with higher temporal resolution than is obtained by fMRI alone thus revealing additional information about their processing mode.

  13. Modulation of the COMT Val(158)Met polymorphism on resting-state EEG power.

    PubMed

    Solís-Ortiz, Silvia; Pérez-Luque, Elva; Gutiérrez-Muñoz, Mayra

    2015-01-01

    The catechol-O-methyltransferase (COMT) Val(158)Met polymorphism impacts cortical dopamine (DA) levels and may influence cortical electrical activity in the human brain. This study investigated whether COMT genotype influences resting-state electroencephalogram (EEG) power in the frontal, parietal and midline regions in healthy volunteers. EEG recordings were conducted in the resting-state in 13 postmenopausal healthy woman carriers of the Val/Val genotype and 11 with the Met/Met genotype. The resting EEG spectral absolute power in the frontal (F3, F4, F7, F8, FC3 and FC4), parietal (CP3, CP4, P3 and P4) and midline (Fz, FCz, Cz, CPz, Pz and Oz) was analyzed during the eyes-open and eyes-closed conditions. The frequency bands considered were the delta, theta, alpha1, alpha2, beta1 and beta2. EEG data of the Val/Val and Met/Met genotypes, brain regions and conditions were analyzed using a general linear model analysis. In the individuals with the Met/Met genotype, delta activity was increased in the eyes-closed condition, theta activity was increased in the eyes-closed and in the eyes-open conditions, and alpha1 band, alpha2 band and beta1band activity was increased in the eyes-closed condition. A significant interaction between COMT genotypes and spectral bands was observed. Met homozygote individuals exhibited more delta, theta and beta1 activity than individuals with the Val/Val genotype. No significant interaction between COMT genotypes and the resting-state EEG regional power and conditions were observed for the three brain regions studied. Our findings indicate that the COMT Val(158)Met polymorphism does not directly impact resting-state EEG regional power, but instead suggest that COMT genotype can modulate resting-state EEG spectral power in postmenopausal healthy women.

  14. Anatomical Substrate and Scalp EEG Markers are Correlated in Subjects with Cognitive Impairment and Alzheimer's Disease.

    PubMed

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

    2011-01-01

    Dementia is a syndromic diagnosis, encompassing various stage of severity and different anatomo-physiological substrates. The hippocampus is one of the first and most affected brain regions affected by both Alzheimer's disease (AD) and mild cognitive impairment (MCI). Moreover, chronic cerebrovascular disease (CVD) is one of the major risk factor for developing dementia. Recent studies have demonstrated different relationship between the anatomical substrate and scalp electroencephalography (EEG) markers. Indeed, modifications of EEG rhythmicity is not proportional to the hippocampal atrophy, whereas changes in EEG activity are directly proportional to the load of subcortical CVD. The computation of the EEG spectral power and the analysis of the functional coupling of brain areas, through linear coherence, are two of the most known processing methods in EEG research. Two specific EEG markers, theta/gamma and alpha3/alpha2 frequency ratio have been reliable associated to the atrophy of amygdalo-hippocampal complex. Moreover, theta/gamma ratio has been related to MCI conversion in dementia and alpha3/alpha2 ratio has been specifically related to MCI conversion in AD. The functional coupling of brain areas is also modulated by hippocampal atrophy. In the MCI subjects, hippocampal atrophy is linked to an increase of interhemispheric coherence seen on frontal and temporal regions whereas subcortical CVD is linked to a decrease of coherence in fronto-parietal regions. In the present study the most significant results of recent studies on correlation between scalp EEG, cognitive decline, and anatomical substrate have been reviewed, with particular attention to the relationships between EEG changes and hippocampal atrophy. The following review is not intended to provide a comprehensive summary of the literature. Rather it identifies and discusses selected studies that are designed to find the specific correlation between scalp EEG markers and anatomo-pathological substrate

  15. Distributed analysis of simultaneous EEG-fMRI time-series: modeling and interpretation issues.

    PubMed

    Esposito, Fabrizio; Aragri, Adriana; Piccoli, Tommaso; Tedeschi, Gioacchino; Goebel, Rainer; Di Salle, Francesco

    2009-10-01

    Functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) represent brain activity in terms of a reliable anatomical localization and a detailed temporal evolution of neural signals. Simultaneous EEG-fMRI recordings offer the possibility to greatly enrich the significance and the interpretation of the single modality results because the same neural processes are observed from the same brain at the same time. Nonetheless, the different physical nature of the measured signals by the two techniques renders the coupling not always straightforward, especially in cognitive experiments where spatially localized and distributed effects coexist and evolve temporally at different temporal scales. The purpose of this article is to illustrate the combination of simultaneously recorded EEG and fMRI signals exploiting the principles of EEG distributed source modeling. We define a common source space for fMRI and EEG signal projection and gather a conceptually unique framework for the spatial and temporal comparative analysis. We illustrate this framework in a graded-load working-memory simultaneous EEG-fMRI experiment based on the n-back task where sustained load-dependent changes in the blood-oxygenation-level-dependent (BOLD) signals during continuous item memorization co-occur with parametric changes in the EEG theta power induced at each single item. In line with previous studies, we demonstrate on two single-subject cases how the presented approach is capable of colocalizing in midline frontal regions two phenomena simultaneously observed at different temporal scales, such as the sustained negative changes in BOLD activity and the parametric EEG theta synchronization. We discuss the presented approach in relation to modeling and interpretation issues typically arising in simultaneous EEG-fMRI studies.

  16. Frontal midline theta oscillations during mental arithmetic: effects of stress.

    PubMed

    Gärtner, Matti; Grimm, Simone; Bajbouj, Malek

    2015-01-01

    Complex cognitive tasks such as mental arithmetic heavily rely on intact, well-coordinated prefrontal cortex (PFC) function. Converging evidence suggests that frontal midline theta (FMT) oscillations play an important role during the execution of such PFC-dependent tasks. Additionally, it is well-established that acute stress impairs PFC function, and recent evidence suggests that FMT is decreased under stress. In this EEG study, we investigated FMT oscillations during a mental arithmetic task that was carried out in a stressful and a neutral control condition. Our results show late-onset, sustained FMT increases during mental arithmetic. In the neutral condition FMT started to increase earlier than in the stress condition. Direct comparison of the conditions quantified this difference by showing stronger FMT increases in the neutral condition in an early time window. Between-subject correlation analysis showed that attenuated FMT under stress was related to slowed reaction times. Our results suggest that FMT is associated with stimulus independent mental processes during the natural and complex PFC-dependent task of mental arithmetic, and is a possible marker for intact PFC function that is disrupted under stress.

  17. 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

  18. 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

  19. Measuring Theta_13 at Daya Bay

    SciTech Connect

    Lau, Kwong

    2014-03-14

    We measured the neutrino mixing angle, theta13, presumably related to the preponderance of matter over antimatter in our universe with high precision. We determined theta13 by measuring the disappearance of neutrinos from a group of six nuclear reactors. The target, located inside a mountain at about 2 km from the reactors, is 80 tons of liquid scintillator doped with trace amount of Gadolinium to increase its neutron detection efficiency. The neutrino flux is measured by the inverse beta-decay reaction where the final-state particles are detected by the liquid scintillator. The measured value of theta13, based on data collected over 3 years, is large, around 8 degrees, rendering the measurement of the parameter related to matter-antimatter asymmetry in future long baseline neutrino experiments easier.

  20. Learning alters theta amplitude, theta-gamma coupling and neuronal synchronization in inferotemporal cortex

    PubMed Central

    2011-01-01

    Background How oscillatory brain rhythms alone, or in combination, influence cortical information processing to support learning has yet to be fully established. Local field potential and multi-unit neuronal activity recordings were made from 64-electrode arrays in the inferotemporal cortex of conscious sheep during and after visual discrimination learning of face or object pairs. A neural network model has been developed to simulate and aid functional interpretation of learning-evoked changes. Results Following learning the amplitude of theta (4-8 Hz), but not gamma (30-70 Hz) oscillations was increased, as was the ratio of theta to gamma. Over 75% of electrodes showed significant coupling between theta phase and gamma amplitude (theta-nested gamma). The strength of this coupling was also increased following learning and this was not simply a consequence of increased theta amplitude. Actual discrimination performance was significantly correlated with theta and theta-gamma coupling changes. Neuronal activity was phase-locked with theta but learning had no effect on firing rates or the magnitude or latencies of visual evoked potentials during stimuli. The neural network model developed showed that a combination of fast and slow inhibitory interneurons could generate theta-nested gamma. By increasing N-methyl-D-aspartate receptor sensitivity in the model similar changes were produced as in inferotemporal cortex after learning. The model showed that these changes could potentiate the firing of downstream neurons by a temporal desynchronization of excitatory neuron output without increasing the firing frequencies of the latter. This desynchronization effect was confirmed in IT neuronal activity following learning and its magnitude was correlated with discrimination performance. Conclusions Face discrimination learning produces significant increases in both theta amplitude and the strength of theta-gamma coupling in the inferotemporal cortex which are correlated with

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

    PubMed Central

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

    2016-01-01

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

  2. Nonconvulsive Status Epilepticus Resembling Clinical Absence with Atypical EEG Pattern

    PubMed Central

    Mysore, Channaiah Srikanth; Zabad, Rana; Bertoni, John

    2017-01-01

    Objective. We are reporting two cases: a patient with steroid responsive encephalopathy associated with autoimmune thyroiditis (SREAT) and another patient with secondary progressive multiple sclerosis (SPMS), both presenting with altered mental status (AMS) and later diagnosed with nonconvulsive atypical absence status epilepticus (AS), with atypical EEG changes. Methods. A report of two cases. Results. A patient with history of SREAT and the other with SPMS had multiple admissions due to AMS. For both, EEG revealed the presence of a high voltage generalized sharply contoured theta activity. A diagnosis of NCSE with clinical features of AS was made based on both clinical and EEG features. There was significant clinical and electrographic improvement with administration of levetiracetam for both patients in addition to sodium valproate and Solumedrol for the SREAT patient. Both patients continued to be seizure free on follow-up few months later. Conclusions. This is a report of two cases of atypical AS, with atypical EEG, in patients with different neurological conditions. Prompt clinical and EEG recovery occurred following appropriate medical treatment. We think that this condition might be underreported and could significantly benefit from prompt treatment when appropriately diagnosed. PMID:28203468

  3. The characteristics of EEG power spectra changes after ACL rupture

    PubMed Central

    Miao, Xin; Huang, Hongshi; Hu, Xiaoqing; Li, Dai; Yu, Yuanyuan; Ao, Yingfang

    2017-01-01

    Background Reestablishing knee stability is the core of the treatment of ACL (Anterior Cruciate Ligament) injury. Some patients still have a feeling of instability of the knee after ACL injury treatment. This unstable feeling may be caused by central nervous system changes after ACL rupture. Methods To identify the central changes after ACL rupture, EEG spectra were recorded to compare ACL patients and healthy controls when they were walking, jogging, and landing. Results There was a significant increase in delta, theta, alpha and beta band power during walking, jogging and landing in ACL patients. We also found an asymmetry phenomenon of EEG only in the ACL patients, mainly in the frontal area and central-parietal area. The asymmetry of beta band power extended to the frontal and the central area during jogging and landing task. Conclusions There were significant differences in EEG power spectra between the ACL patients and healthy people. ACL patients showed high EEG band power activities and an asymmetry phenomenon. EEG power changes were affected by movements, the asymmetry extended when performing more complicated movements. PMID:28182627

  4. Maternal dexamethasone and EEG hyperactivity in preterm fetal sheep

    PubMed Central

    Davidson, Joanne O; Quaedackers, Josine S L T; George, Sherly A; Gunn, Alistair Jan; Bennet, Laura

    2011-01-01

    Abstract Maternal treatment with synthetic corticosteroids such as dexamethasone (DEX) significantly reduces neonatal morbidity and mortality, but its effects on the fetal brain remain unclear. In this study we evaluated the effects of DEX on EEG activity in preterm fetal sheep. Ewes at 103 days gestation received two intramuscular injections of DEX (12 mg, n = 8) or saline vehicle (n = 7) 24 h apart. Fetal EEG activity was recorded from 6 h before until 120 h after the first injection (DEX-1). DEX-1 was associated with a marked transient rise in total EEG power, maximal at 12 h (P < 0.001), with a relative increase in delta and reduced theta, alpha and beta activity, resolving by 24 h. Continuous EEG records showed a shift to larger but less frequent transient waveforms (P < 0.001). Unexpectedly, evolving epileptiform activity, consistent with electrographic and clinical seizures, developed from 178 ± 44 min after DEX-1. Similar but smaller changes were seen after the second injection. Following the injections, total power returned to control values, but the proportion of alpha activity progressively increased vs. controls (P < 0.001), with reduced interburst interval duration and number (P < 0.001). No histological neural injury or microglial activation was seen. In summary, exposure to maternal dexamethasone was associated with dramatic, evolving low-frequency hyperactivity on fetal cortical EEG recordings, followed by sustained changes consistent with maturation of fetal sleep architecture. We postulate that these effects may contribute to improved neonatal outcomes. PMID:21646408

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

    PubMed Central

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

    2015-01-01

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

  6. Transient Global Amnesia Deteriorates the Network Efficiency of the Theta Band

    PubMed Central

    Yi, SangHak; Lim, Jae-Sung; Jang, Jae-Won; Im, Chang-Hwan; Kim, SangYun

    2016-01-01

    Acute perturbation of the hippocampus, one of the connector hubs in the brain, is a key step in the pathophysiological cascade of transient global amnesia (TGA). We tested the hypothesis that network efficiency, meaning the efficiency of information exchange over a network, is impaired during the acute stage of TGA. Graph theoretical analysis was applied to resting-state EEG data collected from 21 patients with TGA. The EEG data were obtained twice, once during the acute stage (< 24 hours after symptom onset) and once during the resolved stage (> 2 months after symptom onset) of TGA. Characteristic path lengths and clustering coefficients of functional networks constructed using phase-locking values were computed and normalized as a function of the degree in the delta, theta, alpha, beta 1, beta 2 and gamma frequency bands of the EEG. We investigated whether the normalized characteristic path length (nCPL) and normalized clustering coefficients (nCC) differed significantly between the acute and resolved stages of TGA at each frequency band using the Wilcoxon signed-rank test. For networks where the nCPL or nCC differed significantly between the two stages, we also evaluated changes in the connections of the brain networks. During the acute stage of TGA, the nCPL of the theta band networks with mean degrees of 8, 8.5, 9 and 9.5 significantly increased (P < 0.05). During the acute stage, the lost edges for these networks were mostly found between the anterior (frontal and anterior temporal) and posterior (parieto-occipital and posterior temporal) brain regions, whereas newly developed edges were primarily found between the left and right frontotemporal regions. The nCC of the theta band with a mean degree of 5.5 significantly decreased during the acute stage (P < 0.05). Our results indicate that TGA deteriorates the network efficiency of the theta frequency band. This effect might be related to the desynchronization between the anterior and posterior brain areas

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

    PubMed Central

    Papagiannopoulou, Eleni A.; Lagopoulos, Jim

    2016-01-01

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

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

    PubMed

    Papagiannopoulou, Eleni A; Lagopoulos, Jim

    2016-01-01

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

  9. Event-Related Theta Power during Lexical-Semantic Retrieval and Decision Conflict is Modulated by Alcohol Intoxication: Anatomically Constrained MEG

    PubMed Central

    Marinkovic, Ksenija; Rosen, Burke Q.; Cox, Brendan; Kovacevic, Sanja

    2012-01-01

    Language processing is commonly characterized by an event-related increase in theta power (4–7 Hz) in scalp EEG. Oscillatory brain dynamics underlying alcohol’s effects on language are poorly understood despite impairments on verbal tasks. To investigate how moderate alcohol intoxication modulates event-related theta activity during visual word processing, healthy social drinkers (N = 22, 11 females) participated in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions in a counterbalanced design. They performed a double-duty lexical decision task as they detected real words among non-words. An additional requirement to respond to all real words that also referred to animals induced response conflict. High density whole-head MEG signals and midline scalp EEG data were decomposed for each trial with Morlet wavelets. Each person’s reconstructed cortical surface was used to constrain noise-normalized distributed minimum norm inverse solutions for theta frequencies. Alcohol intoxication increased reaction time and marginally affected accuracy. The overall spatio-temporal pattern is consistent with the left-lateralized fronto-temporal activation observed in language studies applying time-domain analysis. Event-related theta power was sensitive to the two functions manipulated by the task. First, theta estimated to the left-lateralized fronto-temporal areas reflected lexical-semantic retrieval, indicating that this measure is well suited for investigating the neural basis of language functions. While alcohol attenuated theta power overall, it was particularly deleterious to semantic retrieval since it reduced theta to real words but not pseudowords. Second, a highly overlapping prefrontal network comprising lateral prefrontal and anterior cingulate cortex was sensitive to decision conflict and was also affected by intoxication, in agreement with previous studies indicating that executive functions are especially vulnerable to

  10. Theta oscillations are affected by amnestic mild cognitive impairment and cognitive load.

    PubMed

    Cummins, Tarrant D R; Broughton, Megan; Finnigan, Simon

    2008-10-01

    Amnestic mild cognitive impairment (aMCI) is classified primarily via substantial episodic memory deficits in the absence of a dementia diagnosis. To investigate the potential neurophysiological correlates of such deficits we compared QEEG power between 12 participants with aMCI and 12 healthy matched controls. EEG was acquired during performance of a modified Sternberg word recognition task with low and high memory load conditions. While recognition accuracy of aMCI participants was lower than that of controls, this difference was not significant. Nevertheless the aMCI group demonstrated significantly lower theta power at a number of electrode sites and significant correlations were observed between power at these sites and neuropsychological assessment scores. Furthermore in the aMCI sample only, theta power was significantly lower under high versus low memory load. Given current interpretations of the neural generator(s), as well as the role(s), of theta oscillations in cognitive processes, the present data indicate that aMCI may be associated with disruptions in the operation of neurocognitive networks (e.g., MTL-neocortical), particularly under high cognitive load.

  11. Cross-correlation of EEG frequency bands and heart rate variability for sleep apnoea classification.

    PubMed

    Abdullah, Haslaile; Maddage, Namunu C; Cosic, Irena; Cvetkovic, Dean

    2010-12-01

    Sleep apnoea is a sleep breathing disorder which causes changes in cardiac and neuronal activity and discontinuities in sleep pattern when observed via electrocardiogram (ECG) and electroencephalogram (EEG). Using both statistical analysis and Gaussian discriminative modelling approaches, this paper presents a pilot study of assessing the cross-correlation between EEG frequency bands and heart rate variability (HRV) in normal and sleep apnoea clinical patients. For the study we used EEG (delta, theta, alpha, sigma and beta) and HRV (LF(nu), HF(nu) and LF/HF) features from the spectral analysis. The statistical analysis in different sleep stages highlighted that in sleep apnoea patients, the EEG delta, sigma and beta bands exhibited a strong correlation with HRV features. Then the correlation between EEG frequency bands and HRV features were examined for sleep apnoea classification using univariate and multivariate Gaussian models (UGs and MGs). The MG outperformed the UG in the classification. When EEG and HRV features were combined and modelled with MG, we achieved 64% correct classification accuracy, which is 2 or 8% improvement with respect to using only EEG or ECG features. When delta and acceleration coefficients of the EEG features were incorporated, then the overall accuracy improved to 71%.

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

    PubMed

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

    2012-04-01

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

  13. Human brain networks in cognitive decline: a graph theoretical analysis of cortical connectivity from EEG data.

    PubMed

    Vecchio, Fabrizio; Miraglia, Francesca; Marra, Camillo; Quaranta, Davide; Vita, Maria Gabriella; Bramanti, Placido; Rossini, Paolo Maria

    2014-01-01

    The aim of this study was to investigate the neuronal network characteristics in physiological and pathological brain aging. A database of 378 participants divided in three groups was analyzed: Alzheimer's disease (AD), mild cognitive impairment (MCI), and normal elderly (Nold) subjects. Through EEG recordings, cortical sources were evaluated by sLORETA software, while graph theory parameters (Characteristic Path Length λ, Clustering coefficient γ, and small-world network σ) were computed to the undirected and weighted networks, obtained by the lagged linear coherence evaluated by eLORETA software. EEG cortical sources from spectral analysis showed significant differences in delta, theta, and alpha 1 bands. Furthermore, the analysis of eLORETA cortical connectivity suggested that for the normalized Characteristic Path Length (λ) the pattern differences between normal cognition and dementia were observed in the theta band (MCI subjects are find similar to healthy subjects), while for the normalized Clustering coefficient (γ) a significant increment was found for AD group in delta, theta, and alpha 1 bands; finally, the small world (σ) parameter presented a significant interaction between AD and MCI groups showing a theta increase in MCI. The fact that AD patients respect the MCI subjects were significantly impaired in theta but not in alpha bands connectivity are in line with the hypothesis of an intermediate status of MCI between normal condition and overt dementia.

  14. (No) time for control: Frontal theta dynamics reveal the cost of temporally guided conflict anticipation.

    PubMed

    van Driel, Joram; Swart, Jennifer C; Egner, Tobias; Ridderinkhof, K Richard; Cohen, Michael X

    2015-12-01

    During situations of response conflict, cognitive control is characterized by prefrontal theta-band (3- to 8-Hz) activity. It has been shown that cognitive control can be triggered proactively by contextual cues that predict conflict. Here, we investigated whether a pretrial preparation interval could serve as such a cue. This would show that the temporal contingencies embedded in the task can be used to anticipate upcoming conflict. To this end, we recorded electroencephalography (EEG) from 30 human subjects while they performed a version of a Simon task in which the duration of a fixation cross between trials predicted whether the next trial would contain response conflict. Both their behavior and EEG activity showed a consistent but unexpected pattern of results: The conflict effect (increased reaction times and decreased accuracy on conflict as compared to nonconflict trials) was stronger when conflict was cued, and this was associated with stronger conflict-related midfrontal theta activity and functional connectivity. Interestingly, intervals that predicted conflict did show a pretarget increase in midfrontal theta power. These findings suggest that temporally guided expectations of conflict do heighten conflict anticipation, but also lead to less efficiently applied reactive control. We further explored this post-hoc interpretation by means of three behavioral follow-up experiments, in which we used nontemporal cues, semantically informative cues, and neutral cues. Together, this body of results suggests that the counterintuitive cost of conflict cueing may not be uniquely related to the temporal domain, but may instead be related to the implicitness and validity of the cue.

  15. Quantitative analysis of EEG effects following experimental marginal magnesium and boron deprivation.

    PubMed

    Penland, J G

    1995-12-01

    Magnesium (115 and 315 mg/d) and boron (0.23 and 3.23 mg/d) were fed in a double-blind Latin squares design to 13 healthy postmenopausal women (aged 50-78 years) living on a metabolic unit. An eight-channel electroencephalogram (EEG) was recorded during the last week of each of four 6-week dietary periods. Power and coherence measures were determined for each of four EEG frequency bands: delta (1-3 Hz), theta (4-7 Hz), alpha (8-12 Hz), and beta (13-18 Hz). Compared to high dietary magnesium, the low magnesium intake increased total power in the frontal regions and right temporal and parietal regions and resulted in frequency-specific increases in left occipital delta power, theta power in all but the left temporal region, alpha power in the right frontal and right temporal regions, and beta power in the frontal regions. The proportion of theta to total power in the parietal regions also increased with the low magnesium intake. While magnesium effects were observed primarily during eyes-closed conditions, effects of dietary boron on EEG power were found only during eyes-open conditions. Relative to high dietary boron, the low boron intake increased delta power in the left parietal and left occipital regions, increased the proportion of delta to total power in the frontal regions, and decreased relative right frontal theta, right frontal alpha, and left frontal beta power. Additional magnesium and boron effects were evident in the measures of EEG coherence. Thus relatively short periods of marginal magnesium and boron deprivation can affect brain function in healthy older women. The findings extend previous qualitative observations of increased CNS activity following severe magnesium deprivation and deficiency to cases of experimentally induced marginal magnesium deficiency, and verify CNS hyperexcitability by quantitative analysis of the EEG.

  16. Motor Cortex Theta and Gamma Architecture in Young Adult APPswePS1dE9 Alzheimer Mice

    PubMed Central

    Lundt, Andreas; Wormuth, Carola; Ginde, Varun Raj; Müller, Ralf; Henseler, Christina; Broich, Karl; Xie, Kan; Haenisch, Britta; Ehninger, Dan; Weiergräber, Marco

    2017-01-01

    Alzheimer’s disease (AD) is a multifactorial disorder leading to progressive memory loss and eventually death. In this study, an APPswePS1dE9 AD mouse model has been analyzed for motor cortex theta, beta and gamma frequency alterations using computerized 3D stereotaxic electrode positioning and implantable video-EEG radiotelemetry to perform long-term M1 recordings from both genders considering age, circadian rhythm and activity status of experimental animals. We previously demonstrated that APPswePS1dE9 mice exibit complex alterations in hippocampal frequency power and another recent investigation reported a global increase of alpha, beta and gamma power in APPswePS1dE9 in females of 16–17 weeks of age. In this cortical study in APPswePS1dE9 mice we did not observe any changes in theta, beta and particularly gamma power in both genders at the age of 14, 15, 18 and 19 weeks. Importantly, no activity dependence of theta, beta and gamma activity could be detected. These findings clearly point to the fact that EEG activity, particularly gamma power exhibits developmental changes and spatial distinctiveness in the APPswePS1dE9 mouse model of Alzheimer’s disease. PMID:28072877

  17. Higher theta and alpha1 coherence when listening to Vedic recitation compared to coherence during Transcendental Meditation practice.

    PubMed

    Travis, Frederick; Parim, Niyazi; Shrivastava, Amrita

    2017-03-01

    This study compared subjective experiences and EEG patterns in 37 subjects when listening to live Vedic recitation and when practicing Transcendental Meditation (TM). Content analysis of experiences when listening to Vedic recitation yielded three higher-order code. Experiences during Vedic recitation were: (1) deeper than during TM practice; (2) experienced as an inner process; and (3) characterized by lively silence. EEG patterns support these higher-order codes. Theta2 and alpha1 frontal, parietal, and frontal-parietal coherence were significantly higher when listening to Vedic recitation, than during TM practice. Theta2 coherence is seen when attending to internal mental processes. Higher theta2 coherence supports subjects' descriptions that the Vedic recitations were "not external sounds but internal vibrations." Alpha1 coherence is reported during pure consciousness experiences during TM practice. Higher alpha1 coherence supports subjects' descriptions that they "experienced a depth of experience, rarely experienced even during deep TM practice." These data support the utility of listening to Vedic recitation to culture deep inner experiences.

  18. Holomorphic projections and Ramanujan's mock theta functions.

    PubMed

    Imamoğlu, Özlem; Raum, Martin; Richter, Olav K

    2014-03-18

    We use spectral methods of automorphic forms to establish a holomorphic projection operator for tensor products of vector-valued harmonic weak Maass forms and vector-valued modular forms. We apply this operator to discover simple recursions for Fourier series coefficients of Ramanujan's mock theta functions.

  19. Autonomic and EEG correlates of emotional imagery in subjects with different hypnotic susceptibility.

    PubMed

    Sebastiani, L; Simoni, A; Gemignani, A; Ghelarducci, B; Santarcangelo, E L

    2003-04-15

    The autonomic and EEG correlates of the response to a cognitive unpleasant stimulation (US) verbally administered to awake hypnotizable and non hypnotizable subjects were studied. They were compared with the values obtained during a resting condition immediately preceding the stimulus and with those produced by a cognitive neutral stimulation (NS), also administered after a basal resting period. Results showed hypnotic trait effects on skin resistance, heart and respiratory rate as well as on EEG theta, alpha, beta and gamma relative power changes. The autonomic and EEG patterns observed indicated different strategies in the task execution for hypnotizable and non hypnotizable subjects and a discrepancy between the autonomic and EEG changes associated to the US in susceptible subjects. Results support dissociation theories of hypnosis and suggest for hypnotizable persons an active mechanism of protection against cardiac hazard.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  1. Slow EEG-power spectra correlate with haemodynamic changes during laryngoscopy and intubation following induction with fentanyl or sufentanil.

    PubMed

    Freye, E; Dehnen-Seipel, H; Latasch, L; Behler, M; Wilder-Smith, O H

    1999-01-01

    We studied nociception-associated arousal following laryngoscopy and intubation in patients scheduled for elective open heart surgery, using EEG power spectra and hemodynamics. Either fentanyl (7 micrograms/kg; n = 30) or sufentanil (1 microgram/kg; n = 30) were given in a randomized fashion to induce anesthesia in heavily premedicated patients, followed by pancuronium bromide (100 micrograms/kg). EEG-power spectra (delta, theta, alpha, beta) as well as mean arterial blood pressure (MAP) and heart rate (HF) were measured at the following end-points: before the induction of anesthesia (control), 1 and 10 minutes after laryngoscopy and intubation (L & I). Linear regression analysis was computed to determine which of the EEG power spectra was most sensitive to detect insufficient blockade of nociceptive-related arousal when correlated with haemodynamics. In the fentanyl group the change in HF closely correlated with the decrease of power in the slow delta- and theta-domain (r2 = 0.98 and r2 = 0.89 respectively) of the EEG. The change in MAP also closely correlated with a decrease in the slow delta- and theta-domain (r2 = 0.97 and r2 = 0.99 respectively). There was little correlation in regard to spectral edge frequency (SEF) and HF and MAP changes (r2 = 0.36 and r2 = 0.12 respectively). In the sufentanil group the change in HF correlated closely with an increase of power in the fast alpha and a decrease in the slow theta-domain (r2 = 0.91 and r2 = 0.98 respectively) of the EEG. The changes in MAP closely correlated with an increase in the fast alpha-band a decrease in the slow theta-domain (r2 = 0.98 and r2 = 0.73 respectively). Also there was little correlation of SEF with HF and MAP changes (r2 = 0.09 and r2 = 0.02 respectively). Among the EEG-spectra, reduction of power in the slow delta- and theta-bands are the most sensitive parameters to determine insufficient antinociception of opioids commonly used for the induction in cardiac anesthesia. Increase of power in

  2. Theta-burst Transcranial Magnetic Stimulation Alters the Functional Topography of the Cortical Motor Network

    PubMed Central

    NOH, Nor Azila; FUGGETTA, Giorgio; MANGANOTTI, Paolo

    2015-01-01

    Background: Transcranial magnetic stimulation (TMS) is a non-invasive tool that is able to modulate the electrical activity of the brain depending upon its protocol of stimulation. Theta burst stimulation (TBS) is a high-frequency TMS protocol that is able to induce prolonged plasticity changes in the brain. The induction of plasticity-like effects by TBS is useful in both experimental and therapeutic settings; however, the underlying neural mechanisms of this modulation remain unclear. The aim of this study was to investigate the effects of continuous TBS (cTBS) on the intrahemispheric and interhemispheric functional connectivity of the resting and active brain. Methods: A total of 26 healthy humans were randomly divided into two groups that received either real cTBS or sham (control) over the left primary motor cortex. Surface electroencephalogram (EEG) was used to quantify the changes of neural oscillations after cTBS at rest and after a choice reaction time test. The cTBS-induced EEG oscillations were computed using spectral analysis of event-related coherence (ERCoh) of theta (4–7.5 Hz), low alpha (8–9.5 Hz), high alpha (10–12.5 Hz), low beta (13–19.5 Hz), and high beta (20–30 Hz) brain rhythms. Results: We observed a global decrease in functional connectivity of the brain in the cTBS group when compared to sham in the low beta brain rhythm at rest and high beta brain rhythm during the active state. In particular, EEG spectral analysis revealed that high-frequency beta, a cortically generated brain rhythm, was the most sensitive band that was modulated by cTBS. Conclusion: Overall, our findings suggest that cTBS, a TMS protocol that mimics the mechanism of long-term depression of synaptic plasticity, modulates motor network oscillations primarily at the cortical level and might interfere with cortical information coding. PMID:27006636

  3. Better than sleep: theta neurofeedback training accelerates memory consolidation.

    PubMed

    Reiner, Miriam; Rozengurt, Roman; Barnea, Anat

    2014-01-01

    Consistent empirical results showed that both night and day sleep enhanced memory consolidation. In this study we explore processes of consolidation of memory during awake hours. Since theta oscillations have been shown to play a central role in exchange of information, we hypothesized that elevated theta during awake hours will enhance memory consolidation. We used a neurofeedback protocol, to enhance the relative power of theta or beta oscillations. Participants trained on a tapping task, were divided into three groups: neurofeedback theta; neurofeedback beta; control. We found a significant improvement in performance in the theta group, relative to the beta and control groups, immediately after neurofeedback. Performance was further improved after night sleep in all groups, with a significant advantage favoring the theta group. Theta power during training was correlated with the level of improvement, indicating a clear relationship between memory consolidation, and theta neurofeedback.

  4. Interactions between different EEG frequency bands and their effect on alpha-fMRI correlations.

    PubMed

    de Munck, J C; Gonçalves, S I; Mammoliti, R; Heethaar, R M; Lopes da Silva, F H

    2009-08-01

    In EEG/fMRI correlation studies it is common to consider the fMRI BOLD as filtered version of the EEG alpha power. Here the question is addressed whether other EEG frequency components may affect the correlation between alpha and BOLD. This was done comparing the statistical parametric maps (SPMs) of three different filter models wherein either the free or the standard hemodynamic response functions (HRF) were used in combination with the full spectral bandwidth of the EEG. EEG and fMRI were co-registered in a 30 min resting state condition in 15 healthy young subjects. Power variations in the delta, theta, alpha, beta and gamma bands were extracted from the EEG and used as regressors in a general linear model. Statistical parametric maps (SPMs) were computed using three different filter models, wherein either the free or the standard hemodynamic response functions (HRF) were used in combination with the full spectral bandwidth of the EEG. Results show that the SPMs of different EEG frequency bands, when significant, are very similar to that of the alpha rhythm. This is true in particular for the beta band, despite the fact that the alpha harmonics were discarded. It is shown that inclusion of EEG frequency bands as confounder in the fMRI-alpha correlation model has a large effect on the resulting SPM, in particular when for each frequency band the HRF is extracted from the data. We conclude that power fluctuations of different EEG frequency bands are mutually highly correlated, and that a multi frequency model is required to extract the SPM of the frequency of interest from EEG/fMRI data. When no constraints are put on the shapes of the HRFs of the nuisance frequencies, the correlation model looses so much statistical power that no correlations can be detected.

  5. Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci

    PubMed Central

    Volberg, Gregor; Goldhacker, Markus; Hanslmayr, Simon

    2016-01-01

    Abstract The method of loci is one, if not the most, efficient mnemonic encoding strategy. This spatial mnemonic combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial and associative memory processes. During such processes, fMRI studies consistently demonstrate MTL activity, while electrophysiological studies have emphasized the important role of theta oscillations (3–8 Hz) in the MTL. However, it is still unknown whether increases or decreases in theta power co-occur with increased BOLD signal in the MTL during memory encoding. To investigate this question, we recorded EEG and fMRI separately, while human participants used the spatial method of loci or the pegword method, a similarly associative but nonspatial mnemonic. The more effective spatial mnemonic induced a pronounced theta power decrease source localized to the left MTL compared with the nonspatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. Successful encoding, irrespective of the strategy used, elicited decreases in left temporal theta power and increases in MTL BOLD activity. This pattern of results suggests a negative relationship between theta power and BOLD signal changes in the MTL during memory encoding and spatial processing. The findings extend the well known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL. PMID:28101523

  6. Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci.

    PubMed

    Fellner, Marie-Christin; Volberg, Gregor; Wimber, Maria; Goldhacker, Markus; Greenlee, Mark W; Hanslmayr, Simon

    2016-01-01

    The method of loci is one, if not the most, efficient mnemonic encoding strategy. This spatial mnemonic combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial and associative memory processes. During such processes, fMRI studies consistently demonstrate MTL activity, while electrophysiological studies have emphasized the important role of theta oscillations (3-8 Hz) in the MTL. However, it is still unknown whether increases or decreases in theta power co-occur with increased BOLD signal in the MTL during memory encoding. To investigate this question, we recorded EEG and fMRI separately, while human participants used the spatial method of loci or the pegword method, a similarly associative but nonspatial mnemonic. The more effective spatial mnemonic induced a pronounced theta power decrease source localized to the left MTL compared with the nonspatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. Successful encoding, irrespective of the strategy used, elicited decreases in left temporal theta power and increases in MTL BOLD activity. This pattern of results suggests a negative relationship between theta power and BOLD signal changes in the MTL during memory encoding and spatial processing. The findings extend the well known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL.

  7. Self-generated theta oscillations in the hippocampus.

    PubMed

    Goutagny, Romain; Jackson, Jesse; Williams, Sylvain

    2009-12-01

    Hippocampal theta rhythm is crucial for spatial memory and is thought to be generated by extrinsic inputs. In contrast, using a complete rat hippocampus in vitro, we found several intrinsic, atropine-resistant theta generators in CA1. These oscillators were organized along the septotemporal axis and arose independently from CA3. Our results suggest that CA1 theta rhythm can emerge from the coupling of multiple autonomous hippocampal theta oscillators.

  8. Theta/beta neurofeedback in children with ADHD: Feasibility of a short-term setting and plasticity effects.

    PubMed

    Van Doren, Jessica; Heinrich, Hartmut; Bezold, Mareile; Reuter, Nina; Kratz, Oliver; Horndasch, Stefanie; Berking, Matthias; Ros, Tomas; Gevensleben, Holger; Moll, Gunther H; Studer, Petra

    2017-02-01

    Neurofeedback (NF) is increasingly used as a therapy for attention-deficit/hyperactivity disorder (ADHD), however behavioral improvements require 20 plus training sessions. More economic evaluation strategies are needed to test methodological optimizations and mechanisms of action. In healthy adults, neuroplastic effects have been demonstrated directly after a single session of NF training. The aim of our study was to test the feasibility of short-term theta/beta NF in children with ADHD and to learn more about the mechanisms underlying this protocol. Children with ADHD conducted two theta/beta NF sessions. In the first half of the sessions, three NF trials (puzzles as feedback animations) were run with pre- and post-reading and picture search tasks. A significant decrease of the theta/beta ratio (TBR), driven by a decrease of theta activity, was found in the NF trials of the second session demonstrating rapid and successful neuroregulation by children with ADHD. For pre-post comparisons, children were split into good vs. poor regulator groups based on the slope of their TBR over the NF trials. For the reading task, significant EEG changes were seen for the theta band from pre- to post-NF depending on individual neuroregulation ability. This neuroplastic effect was not restricted to the feedback electrode Cz, but appeared as a generalized pattern, maximal over midline and right-hemisphere electrodes. Our findings indicate that short-term NF may be a valuable and economical tool to study the neuroplastic mechanisms of targeted NF protocols in clinical disorders, such as theta/beta training in children with ADHD.

  9. Frontal-posterior theta oscillations reflect memory retrieval during sentence comprehension.

    PubMed

    Meyer, Lars; Grigutsch, Maren; Schmuck, Noura; Gaston, Phoebe; Friederici, Angela D

    2015-10-01

    Successful working-memory retrieval requires that items be retained as distinct units. At the neural level, it has been shown that theta-band oscillatory power increases with the number of to-be-distinguished items during working-memory retrieval. Here we hypothesized that during sentence comprehension, verbal-working-memory retrieval demands lead to increased theta power over frontal cortex, supposedly supporting the distinction amongst stored items during verbal-working-memory retrieval. Also, synchronicity may increase between the frontal cortex and the posterior cortex, with the latter supposedly supporting item retention. We operationalized retrieval by using pronouns, which refer to and trigger the retrieval of antecedent nouns from a preceding sentence part. Retrieval demand was systematically varied by changing the pronoun antecedent: Either, it was non-embedded in the preceding main clause, and thus easy-to-retrieve across a single clause boundary, or embedded in the preceding subordinate clause, and thus hard-to-retrieve across a double clause boundary. We combined electroencephalography (EEG), scalp-level time-frequency analysis, source localization, and source-level coherence analysis, observing a frontal-midline and broad left-hemispheric theta-power increase for embedded-antecedent compared to non-embedded-antecedent retrieval. Sources were localized to left-frontal, left-parietal, and bilateral-inferior-temporal cortices. Coherence analyses suggested synchronicity between left-frontal and left-parietal and between left-frontal and right-inferior-temporal cortices. Activity of an array of left-frontal, left-parietal, and bilateral-inferior-temporal cortices may thus assist retrieval during sentence comprehension, potentially indexing the orchestration of item distinction, verbal working memory, and long-term memory. Our results extend prior findings by mapping prior knowledge on the functional role of theta oscillations onto processes genuine to human

  10. Impaired Neural Synchrony in the Theta Frequency Range in Adolescents at Familial Risk for Schizophrenia

    PubMed Central

    Donkers, Franc C. L.; Schwikert, Shane R.; Evans, Anna M.; Cleary, Katherine M.; Perkins, Diana O.; Belger, Aysenil

    2011-01-01

    Puberty is a critical period for the maturation of the fronto-limbic and fronto-striate brain circuits responsible for executive function and affective processing. Puberty also coincides with the emergence of the prodromal signs of schizophrenia, which may indicate an association between these two processes. Time-domain analysis and wavelet based time–frequency analysis was performed on electroencephalographic (EEG) data of 30 healthy control (HC) subjects and 24 individuals at familial risk (FR) for schizophrenia. All participants were between the ages of 13 and 18 years and were carefully matched for age, gender, ethnicity, education, and Tanner Stage. Electrophysiological recordings were obtained from 32 EEG channels while participants performed a visual oddball task, where they identified rare visual targets among standard “scrambled” images and rare aversive and neutral distracter pictures. The time-domain analysis showed that during target processing the FR group showed smaller event-related potentials in the P2 and P3 range as compared to the HC group. In addition, EEG activity in the theta (4–8 Hz) frequency range was significantly reduced during target processing in the FR group. Inefficient cortical information processing during puberty may be an early indicator of altered brain function in adolescents at FR for schizophrenia and may represent a vulnerability marker for illness onset. Longitudinal assessments will have to determine their predictive value for illness onset in populations at FR for psychotic illness. PMID:21991257

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  13. Monitoring kidney patients by syntactometric EEG analysis.

    PubMed

    Hernández Sande, C; Arias Rodríguez, J E

    1985-10-01

    The EEG of seriously ill kidney patients reflects changes in their condition which can be measured quantitatively by a syntactic pattern recognition technique. 128 s of an EEG were sampled at 100 Hz and segmented into 4 sec blocks, each of which was labelled D (or d), T (or t), N (or n), S (or s), or B (or b) depending on the position of its main peak in the power spectrum: delta band (0-4 Hz), theta band (4-8 Hz), alpha band (8-12 Hz), sigma band (12-14 Hz) or beta band (over 14 Hz). The use of capital or small letters depends on the size of the peak A refinement of the method also takes into account the second largest peak. The distance of the resulting 32-character 'sentences' from a pattern is calculated using a string-to-string metric based on weighted insertions, deletions and substitutions (insertions and deletions are included to allow for artefacts detected in the signal). Elementary weights have been assigned on empirical medical grounds taking into account the neurological significance of the various spectral bands and their correlation with the levels of creatinine and urea in the bloodstream.

  14. Optimization of EEG frequency bands for improved diagnosis of Alzheimer disease.

    PubMed

    Elgendi, Mohamed; Vialatte, Francois; Cichocki, Andrzej; Latchoumane, Charles; Jeong, Jaesung; Dauwels, Justin

    2011-01-01

    Many clinical studies have shown that electroencephalograms (EEG) of Alzheimer patients (AD) often have an abnormal power spectrum. In this paper a frequency band analysis of AD EEG signals is presented, with the aim of improving the diagnosis of AD from EEG signals. Relative power in different EEG frequency bands is used as features to distinguish between AD patients and healthy control subjects. Many different frequency bands between 4 and 30 Hz are systematically tested, besides the traditional frequency bands, e.g., theta band (4-8 Hz). The discriminative power of the resulting spectral features is assessed through statistical tests (Mann-Whitney U test). Moreover, linear discriminant analysis is conducted with those spectral features. The optimized frequency ranges (4-7 Hz, 8-15 Hz, 19-24 Hz) yield substantially better classification performance than the traditional frequency bands (4-8 Hz, 8-12 Hz, 12-30 Hz); the frequency band 4-7 Hz is the optimal frequency range for detecting AD, which is similar to the classical theta band. The frequency bands were also optimized as features through leave-one-out crossvalidation, resulting in error-free classification. The optimized frequency bands may improve existing EEG based diagnostic tools for AD. Additional testing on larger AD datasets is required to verify the effectiveness of the proposed approach.

  15. Maturational changes in automated EEG spectral power analysis in preterm infants.

    PubMed

    Niemarkt, Hendrik J; Jennekens, Ward; Pasman, Jaco W; Katgert, Titia; Van Pul, Carola; Gavilanes, Antonio W D; Kramer, Boris W; Zimmermann, Luc J; Bambang Oetomo, Sidarto; Andriessen, Peter

    2011-11-01

    Our study aimed at automated power spectral analysis of the EEG in preterm infants to identify changes of spectral measures with maturation. Weekly (10-20 montage) 4-h EEG recordings were performed in 18 preterm infants with GA <32 wk and normal neurological follow-up at 2 y, resulting in 79 recordings studied from 27(+4) to 36(+3) wk of postmenstrual age (PMA, GA + postnatal age). Automated spectral analysis was performed on 4-h EEG recordings. The frequency spectrum was divided in delta 1 (0.5-1 Hz), delta 2 (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) band. Absolute and relative power of each frequency band and spectral edge frequency were calculated. Maturational changes in spectral measures were observed most clearly in the centrotemporal channels. With advancing PMA, absolute powers of delta 1 to 2 and theta decreased. With advancing PMA, relative power of delta 1 decreased and relative powers of alpha and beta increased, respectively. In conclusion, with maturation, spectral analysis of the EEG showed a significant shift from the lower to the higher frequencies. Computer analysis of EEG will allow an objective and reproducible analysis for long-term prognosis and/or stratification of clinical treatment.

  16. Assessing transient cross-frequency coupling in EEG data.

    PubMed

    Cohen, Michael X

    2008-03-15

    Synchronization of oscillatory EEG signals across different frequency bands is receiving waxing interest in cognitive neuroscience and neurophysiology, and cross-frequency coupling is being increasingly linked to cognitive and perceptual processes. Several methods exist to examine cross-frequency coupling, although each has its limitations, typically by being flexible only over time or over frequency. Here, a method for assessing transient cross-frequency coupling is presented, which allows one to test for the presence of multiple, dynamic, and flexible cross-frequency coupling structure over both time and frequency. The method is applied to intracranial EEG data, and strong coupling between gamma ( approximately 40-80 Hz) and upper theta ( approximately 7-9 Hz) was observed. This method might have useful applications in uncovering the electrophysiological correlates of cognitive processes.

  17. Electroencephalographical study of the Rett syndrome with special reference to the monorhythmic theta activities in adult patients.

    PubMed

    Ishizaki, A

    1992-05-01

    The long-term course of the EEG in the Rett syndrome is documented with reference to past studies. The monorhythmic theta activities in the waking state which were characteristically seen in adults with the Rett syndrome were investigated in patients aged between 27 and 28, using auto power spectra. They were often suppressed when the patients were excited or strained. Then the suppression was thought to elevate their conscious levels. The theta activities were often suppressed by calling, but not easily suppressed by other stimuli, especially the somatosensory stimuli of pain and touch. There were also abnormal findings in the ABR and blink reflexes. In the Rett syndrome we, therefore, suspect there are disturbances in the brain stem functions especially in the ascending reticular activating system which is related to elevation of the conscious level.

  18. Promotion

    PubMed Central

    Alam, Hasan B.

    2013-01-01

    This article gives an overview of the promotion process in an academic medical center. A description of different promotional tracks, tenure and endowed chairs, and the process of submitting an application is provided. Finally, some practical advice about developing skills and attributes that can help with academic growth and promotion is dispensed. PMID:24436683

  19. Septal serotonin depletion in rats facilitates working memory in the radial arm maze and increases hippocampal high-frequency theta activity.

    PubMed

    López-Vázquez, Miguel Ángel; López-Loeza, Elisa; Lajud Ávila, Naima; Gutiérrez-Guzmán, Blanca Erika; Hernández-Pérez, J Jesús; Reyes, Yoana Estrada; Olvera-Cortés, María Esther

    2014-07-05

    Hippocampal theta activity, which is strongly modulated by the septal medial/Broca׳s diagonal band neurons, has been linked to information processing of the hippocampus. Serotonin from the medial raphe nuclei desynchronises hippocampal theta activity, whereas inactivation or a lesion of this nucleus induces continuous and persistent theta activity in the hippocampus. Hippocampal serotonin depletion produces an increased expression of high-frequency theta activity concurrent with the facilitation of place learning in the Morris maze. The medial septum-diagonal band of Broca complex (MS/DBB) has been proposed as a key structure in the serotonin modulation of theta activity. We addressed whether serotonin depletion of the MS/DBB induces changes in the characteristics of hippocampal theta activity and whether the depletion is associated with learning in a working memory spatial task in the radial arm maze. Sprague Dawley rats were depleted of 5HT with the infusion of 5,7-dihydroxytriptamine (5,7-DHT) in MS/DBB and were subsequently trained in the standard test (win-shift) in the radial arm, while the CA1 EEG activity was simultaneously recorded through telemetry. The MS/DBB serotonin depletion induced a low level of expression of low-frequency (4.5-6.5Hz) and a higher expression of high-frequency (6.5-9.5Hz) theta activity concomitant to a minor number of errors committed by rats on the working memory test. Thus, the depletion of serotonin in the MS/DBB caused a facilitator effect on working memory and a predominance of high-frequency theta activity.

  20. EEG Signatures of Dynamic Functional Network Connectivity States.

    PubMed

    Allen, E A; Damaraju, E; Eichele, T; Wu, L; Calhoun, V D

    2017-02-22

    The human brain operates by dynamically modulating different neural populations to enable goal directed behavior. The synchrony or lack thereof between different brain regions is thought to correspond to observed functional connectivity dynamics in resting state brain imaging data. In a large sample of healthy human adult subjects and utilizing a sliding windowed correlation method on functional imaging data, earlier we demonstrated the presence of seven distinct functional connectivity states/patterns between different brain networks that reliably occur across time and subjects. Whether these connectivity states correspond to meaningful electrophysiological signatures was not clear. In this study, using a dataset with concurrent EEG and resting state functional imaging data acquired during eyes open and eyes closed states, we demonstrate the replicability of previous findings in an independent sample, and identify EEG spectral signatures associated with these functional network connectivity changes. Eyes open and eyes closed conditions show common and different connectivity patterns that are associated with distinct EEG spectral signatures. Certain connectivity states are more prevalent in the eyes open case and some occur only in eyes closed state. Both conditions exhibit a state of increased thalamocortical anticorrelation associated with reduced EEG spectral alpha power and increased delta and theta power possibly reflecting drowsiness. This state occurs more frequently in the eyes closed state. In summary, we find a link between dynamic connectivity in fMRI data and concurrently collected EEG data, including a large effect of vigilance on functional connectivity. As demonstrated with EEG and fMRI, the stationarity of connectivity cannot be assumed, even for relatively short periods.

  1. Different Resting State EEG Features in Children from Switzerland and Saudi Arabia

    PubMed Central

    Alahmadi, Nsreen; Evdokimov, Sergey A.; Kropotov, Yury (Juri); Müller, Andreas M.; Jäncke, Lutz

    2016-01-01

    Background: Cultural neuroscience is an emerging research field concerned with studying the influences of different cultures on brain anatomy and function. In this study, we examined whether different cultural or genetic influences might influence the resting state electroencephalogram (EEG) in young children (mean age 10 years) from Switzerland and Saudi Arabia. Methods: Resting state EEG recordings were obtained from relatively large groups of healthy children (95 healthy Swiss children and 102 Saudi Arabian children). These EEG data were analyzed using group independent components analyses (gICA) and conventional analyses of spectral data, together with estimations of the underlying intracortical sources, using LORETA software. Results: We identified many similarities, but also some substantial differences with respect to the resting state EEG data. For Swiss children, we found stronger delta band power values in mesial frontal areas and stronger power values in three out of four frequency bands in occipital areas. For Saudi Arabian children, we uncovered stronger alpha band power over the sensorimotor cortex. The additionally measured theta/beta ratio (TBR) was similar for Swiss and Saudi Arabian children. Conclusions: The different EEG resting state features identified, are discussed in the context of different cultural experiences and possible genetic influences. In addition, we emphasize the importance of using appropriate EEG databases when comparing resting state EEG features between groups. PMID:27853430

  2. 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.

  3. The spatiospectral characterization of brain networks: fusing concurrent EEG spectra and fMRI maps.

    PubMed

    Bridwell, David A; Wu, Lei; Eichele, Tom; Calhoun, Vince D

    2013-04-01

    Different imaging modalities capture different aspects of brain activity. Functional magnetic resonance imaging (fMRI) reveals intrinsic networks whose BOLD signals have periods from 100 s (0.01 Hz) to about 10s (0.1 Hz). Electroencephalographic (EEG) recordings, in contrast, commonly reflect cortical electrical fluctuations with periods up to 20 ms (50 Hz) or above. We examined the correspondence between intrinsic fMRI and EEG network activity at rest in order to characterize brain networks both spatially (with fMRI) and spectrally (with EEG). Brain networks were separately identified within the concurrently recorded fMRI and EEG at the aggregate group level with group independent component analysis and the association between spatial fMRI and frequency by spatial EEG sources was examined by deconvolving their component time courses. The two modalities are considered linked if the estimated impulse response function (IRF) is significantly non-zero at biologically plausible delays. We found that negative associations were primarily present within two of five alpha components, which highlights the importance of considering multiple alpha sources in EEG-fMRI. Positive associations were primarily present within the lower (e.g. delta and theta) and higher (e.g. upper beta and lower gamma) spectral regions, sometimes within the same fMRI components. Collectively, the results demonstrate a promising approach to characterize brain networks spatially and spectrally, and reveal that positive and negative associations appear within partially distinct regions of the EEG spectrum.

  4. Event-related EEG time-frequency PCA and the orienting reflex to auditory stimuli.

    PubMed

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

    2015-04-01

    We recently reported an auditory habituation series with counterbalanced indifferent and significant (counting) instructions. Time-frequency (t-f) analysis of electrooculogram-corrected EEG was used to explore event-related synchronization (ERS)/desynchronization (ERD) in four EEG bands using arbitrarily selected time epochs and traditional frequency ranges. ERS in delta, theta, and alpha, and subsequent ERD in theta, alpha, and beta, showed substantial decrement over trials, yet effects of stimulus significance (count vs. no-task) were minimal. Here, we used principal components analysis (PCA) of the t-f data to investigate the natural frequency and time combinations involved in such stimulus processing. We identified four ERS and four ERD t-f components: six showed decrement over trials, four showed count > no-task effects, and six showed Significance × Trial interactions. This increased sensitivity argues for the wider use of our data-driven t-f PCA approach.

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

    PubMed Central

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

    2016-01-01

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

  6. Parvalbumin Interneurons of Hippocampus Tune Population Activity at Theta Frequency.

    PubMed

    Amilhon, Bénédicte; Huh, Carey Y L; Manseau, Frédéric; Ducharme, Guillaume; Nichol, Heather; Adamantidis, Antoine; Williams, Sylvain

    2015-06-03

    Hippocampal theta rhythm arises from a combination of recently described intrinsic theta oscillators and inputs from multiple brain areas. Interneurons expressing the markers parvalbumin (PV) and somatostatin (SOM) are leading candidates to participate in intrinsic rhythm generation and principal cell (PC) coordination in distal CA1 and subiculum. We tested their involvement by optogenetically activating and silencing PV or SOM interneurons in an intact hippocampus preparation that preserves intrinsic connections and oscillates spontaneously at theta frequencies. Despite evidence suggesting that SOM interneurons are crucial for theta, optogenetic manipulation of these interneurons modestly influenced theta rhythm. However, SOM interneurons were able to strongly modulate temporoammonic inputs. In contrast, activation of PV interneurons powerfully controlled PC network and rhythm generation optimally at 8 Hz, while continuously silencing them disrupted theta. Our results thus demonstrate a pivotal role of PV but not SOM interneurons for PC synchronization and the emergence of intrinsic hippocampal theta.

  7. EEG Brain Activity in Dynamic Health Qigong Training: Same Effects for Mental Practice and Physical Training?

    PubMed Central

    Henz, Diana; Schöllhorn, Wolfgang I.

    2017-01-01

    In recent years, there has been significant uptake of meditation and related relaxation techniques, as a means of alleviating stress and fostering an attentive mind. Several electroencephalogram (EEG) studies have reported changes in spectral band frequencies during Qigong meditation indicating a relaxed state. Much less is reported on effects of brain activation patterns induced by Qigong techniques involving bodily movement. In this study, we tested whether (1) physical Qigong training alters EEG theta and alpha activation, and (2) mental practice induces the same effect as a physical Qigong training. Subjects performed the dynamic Health Qigong technique Wu Qin Xi (five animals) physically and by mental practice in a within-subjects design. Experimental conditions were randomized. Two 2-min (eyes-open, eyes-closed) EEG sequences under resting conditions were recorded before and immediately after each 15-min exercise. Analyses of variance were performed for spectral power density data. Increased alpha power was found in posterior regions in mental practice and physical training for eyes-open and eyes-closed conditions. Theta power was increased after mental practice in central areas in eyes-open conditions, decreased in fronto-central areas in eyes-closed conditions. Results suggest that mental, as well as physical Qigong training, increases alpha activity and therefore induces a relaxed state of mind. The observed differences in theta activity indicate different attentional processes in physical and mental Qigong training. No difference in theta activity was obtained in physical and mental Qigong training for eyes-open and eyes-closed resting state. In contrast, mental practice of Qigong entails a high degree of internalized attention that correlates with theta activity, and that is dependent on eyes-open and eyes-closed resting state. PMID:28223957

  8. 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

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

    PubMed

    Fachner, Jörg; Gold, Christian; Erkkilä, Jaakko

    2013-04-01

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

  10. EEG Brain Activity in Dynamic Health Qigong Training: Same Effects for Mental Practice and Physical Training?

    PubMed

    Henz, Diana; Schöllhorn, Wolfgang I

    2017-01-01

    In recent years, there has been significant uptake of meditation and related relaxation techniques, as a means of alleviating stress and fostering an attentive mind. Several electroencephalogram (EEG) studies have reported changes in spectral band frequencies during Qigong meditation indicating a relaxed state. Much less is reported on effects of brain activation patterns induced by Qigong techniques involving bodily movement. In this study, we tested whether (1) physical Qigong training alters EEG theta and alpha activation, and (2) mental practice induces the same effect as a physical Qigong training. Subjects performed the dynamic Health Qigong technique Wu Qin Xi (five animals) physically and by mental practice in a within-subjects design. Experimental conditions were randomized. Two 2-min (eyes-open, eyes-closed) EEG sequences under resting conditions were recorded before and immediately after each 15-min exercise. Analyses of variance were performed for spectral power density data. Increased alpha power was found in posterior regions in mental practice and physical training for eyes-open and eyes-closed conditions. Theta power was increased after mental practice in central areas in eyes-open conditions, decreased in fronto-central areas in eyes-closed conditions. Results suggest that mental, as well as physical Qigong training, increases alpha activity and therefore induces a relaxed state of mind. The observed differences in theta activity indicate different attentional processes in physical and mental Qigong training. No difference in theta activity was obtained in physical and mental Qigong training for eyes-open and eyes-closed resting state. In contrast, mental practice of Qigong entails a high degree of internalized attention that correlates with theta activity, and that is dependent on eyes-open and eyes-closed resting state.

  11. 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.

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

    PubMed Central

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

    2014-01-01

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

  13. Progressive Fracture of [0/90/ + or - Theta]s Composite Structure Under Uniform Pressure Load

    NASA Technical Reports Server (NTRS)

    Gotsis, Pascalis K.; Chamis, Christos C.; Gotsis, Christos K.; Mouratidis, Ericos

    2007-01-01

    S-Glass/epoxy [0/90/plus or minus theta]s for theta =45 deg., 60 deg., and 75 deg. laminated fiber-reinforced composite stiffened plate was simulated to investigated for damage and fracture progression under uniform pressure. An integrated computer code was augmented for the simulation of the damage initiation, growth, accumulation, and propagation to fracture and to structural collapse. Results show in detail the damage progression sequence and structural fracture resistance during different degradation stages. Damage through the thickness of the laminate initiated first at [0/90/plus or minus 45]s at 15.168 MPa (2200 psi), followed by [0/90/plus or minus 60]s at 16.96 MPa (2460 psi) and finally by [0/90/plus or minus 75]s at 19.3 MPa (2800 psi). After damage initiation happened the cracks propagate rapidly to structural fracture.

  14. Invasive EEG explorations.

    PubMed

    Taussig, D; Montavont, A; Isnard, J

    2015-03-01

    The Wada test was adapted from the procedure described by Wada in 1964. It still has a role in the prognostic evaluation of memory disorders after mesial temporal lobectomy. The test consists of injecting a short-acting anesthetic into one hemisphere, under continuous EEG monitoring and during carotid catheterization, to verify the function of contralateral structures. Intracranial EEG recordings deliver signals with few artifacts, and which are quite specific of the zone explored. Three types of electrodes are in common use: (a) foramen ovale (FO) electrodes: electrodes can be inserted directly, without any stereotactic procedure, to provide easy and comparative EEG recordings of the lower and middle portions of the temporal lobe close to the hippocampus. These allow validation of the temporal lobe origin of seizures using FO electrodes recording coupled with scalp EEG; (b): subdural strip or grip electrodes. This relatively aggressive technique carries infectious and hemorrhagic risks and does not allow the exploration of deep cortical structures. However, it permits precise functional cortical mapping via electrical stimulation because of dense and regular positioning of electrodes over the cortical convexity; (c) stereotactically implanted depth electrodes (stereo-electroencephalography [SEEG]). Electrodes are individually planned and inserted within the brain parenchyma through small burr holes. This technique is less aggressive than subdural grid exploration. However it offers relatively limited spatial sampling that may be less well adapted to precise functional evaluation. It allows recording from deep cortical structures and can be argued to be the gold standard of presurgical EEG exploration.

  15. Desynchronization of Theta-Phase Gamma-Amplitude Coupling during a Mental Arithmetic Task in Children with Attention Deficit/Hyperactivity Disorder

    PubMed Central

    Kim, Jun Won; Kim, Bung-Nyun; Lee, Jaewon; Na, Chul; Kee, Baik Seok; Min, Kyung Joon; Han, Doug Hyun; Kim, Johanna Inhyang; Lee, Young Sik

    2016-01-01

    Introduction Theta-phase gamma-amplitude coupling (TGC) measurement has recently received attention as a feasible method of assessing brain functions such as neuronal interactions. The purpose of this electroencephalographic (EEG) study is to understand the mechanisms underlying the deficits in attentional control in children with attention deficit/hyperactivity disorder (ADHD) by comparing the power spectra and TGC at rest and during a mental arithmetic task. Methods Nineteen-channel EEGs were recorded from 97 volunteers (including 53 subjects with ADHD) from a camp for hyperactive children under two conditions (rest and task performance). The EEG power spectra and the TGC data were analyzed. Correlation analyses between the Intermediate Visual and Auditory (IVA) continuous performance test (CPT) scores and EEG parameters were performed. Results No significant difference in the power spectra was detected between the groups at rest and during task performance. However, TGC was reduced during the arithmetic task in the ADHD group compared with the normal group (F = 16.70, p < 0.001). The TGC values positively correlated with the IVA CPT scores but negatively correlated with theta power. Conclusions Our findings suggest that desynchronization of TGC occurred during the arithmetic task in ADHD children. TGC in ADHD children is expected to serve as a promising neurophysiological marker of network deactivation during attention-demanding tasks. PMID:26930194

  16. Correlation of Visuospatial Ability and EEG Slowing in Patients with Parkinson's Disease

    PubMed Central

    Meyer, Antonia; Chaturvedi, Menorca; Hatz, Florian; Gschwandtner, Ute

    2017-01-01

    Background. Visuospatial dysfunction is among the first cognitive symptoms in Parkinson's disease (PD) and is often predictive for PD-dementia. Furthermore, cognitive status in PD-patients correlates with quantitative EEG. This cross-sectional study aimed to investigate the correlation between EEG slowing and visuospatial ability in nondemented PD-patients. Methods. Fifty-seven nondemented PD-patients (17 females/40 males) were evaluated with a comprehensive neuropsychological test battery and a high-resolution 256-channel EEG was recorded. A median split was performed for each cognitive test dividing the patients sample into either a normal or lower performance group. The electrodes were split into five areas: frontal, central, temporal, parietal, and occipital. A linear mixed effects model (LME) was used for correlational analyses and to control for confounding factors. Results. Subsequently, for the lower performance, LME analysis showed a significant positive correlation between ROCF score and parietal alpha/theta ratio (b = .59, p = .012) and occipital alpha/theta ratio (b = 0.50, p = .030). No correlations were found in the group of patients with normal visuospatial abilities. Conclusion. We conclude that a reduction of the parietal alpha/theta ratio is related to visuospatial impairments in PD-patients. These findings indicate that visuospatial impairment in PD-patients could be influenced by parietal dysfunction. PMID:28348918

  17. Different types of theta rhythmicity are induced by social and fearful stimuli in a network associated with social memory

    PubMed Central

    Tendler, Alex; Wagner, Shlomo

    2015-01-01

    Rhythmic activity in the theta range is thought to promote neuronal communication between brain regions. In this study, we performed chronic telemetric recordings in socially behaving rats to monitor electrophysiological activity in limbic brain regions linked to social behavior. Social encounters were associated with increased rhythmicity in the high theta range (7–10 Hz) that was proportional to the stimulus degree of novelty. This modulation of theta rhythmicity, which was specific for social stimuli, appeared to reflect a brain-state of social arousal. In contrast, the same network responded to a fearful stimulus by enhancement of rhythmicity in the low theta range (3–7 Hz). Moreover, theta rhythmicity showed different pattern of coherence between the distinct brain regions in response to social and fearful stimuli. We suggest that the two types of stimuli induce distinct arousal states that elicit different patterns of theta rhythmicity, which cause the same brain areas to communicate in different modes. DOI: http://dx.doi.org/10.7554/eLife.03614.001 PMID:25686218

  18. Analysis of EEG activity in response to binaural beats with different frequencies.

    PubMed

    Gao, Xiang; Cao, Hongbao; Ming, Dong; Qi, Hongzhi; Wang, Xuemin; Wang, Xiaolu; Chen, Runge; Zhou, Peng

    2014-12-01

    When two coherent sounds with nearly similar frequencies are presented to each ear respectively with stereo headphones, the brain integrates the two signals and produces a sensation of a third sound called binaural beat (BB). Although earlier studies showed that BB could influence behavior and cognition, common agreement on the mechanism of BB has not been reached yet. In this work, we employed Relative Power (RP), Phase Locking Value (PLV) and Cross-Mutual Information (CMI) to track EEG changes during BB stimulations. EEG signals were acquired from 13 healthy subjects. Five-minute BBs with four different frequencies were tested: delta band (1 Hz), theta band (5 Hz), alpha band (10 Hz) and beta band (20 Hz). We observed RP increase in theta and alpha bands and decrease in beta band during delta and alpha BB stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified. Connectivity changes were detected following the variation of RP during BB stimulations. Our observation supports the hypothesis that BBs could affect functional brain connectivity, suggesting that the mechanism of BB-brain interaction is worth further study.

  19. EEG Spectral Changes in Treatment Naïve Active Alcoholics

    PubMed Central

    Fein, G.; Allen, J.

    2007-01-01

    Background The present study examines the EEG spectra of actively drinking treatment naïve alcoholics (TxNA). Methods EEGs were gathered on 51 TxNA’s and age and sex-matched controls during eyes-closed conditions. Participants were excluded for lifetime diagnoses of psychiatric or substance abuse disorders. Power for the theta to high beta bands was examined across midline electrodes. Results The TxNA sample exhibited a nexus of disinhibited traits associated with the vulnerability to alcoholism, and had developed alcohol dependence, but no other diagnosable psychiatric or substance abuse disorders. The TxNA subjects evidenced higher power for all EEG bands compared to controls. The magnitude and anterior-posterior extent of the group differences varied across bands. Within the TxNA group, EEG power was negatively correlated with average and peak alcohol drinking duration and average and peak alcohol dose. Conclusions Increased EEG power across the theta to high beta bands distinguishes TxNAs without comorbid diagnoses from controls. These effects varied across bands in their magnitude and spatial extent, suggesting that there are different effects for the different EEG spectral generators. We hypothesize the increased power in these individuals is a trait difference associated with the inherited nexus of disinhibited traits and its manifestation in alcoholism. Based on the strong negative correlations with alcohol use variables, we speculate that decreases in EEG power are a morbid effect of long-term alcohol abuse. We acknowledge that this hypothesized effect of alcohol abuse on EEG power is opposite to the increased EEG power we hypothesize is associated with alcoholism and its inherited nexus of disinhibited traits. An implication of this model is that with continuing alcohol abuse, the increased EEG power in TxNAs will eventually be overpowered by the effects of long-term severe alcohol abuse. This model predicts that in very long-term alcoholics EEG power

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2016-04-01

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

  3. Cognitive-Neural Effects of Brush Writing of Chinese Characters: Cortical Excitation of Theta Rhythm

    PubMed Central

    Xu, Min; Kao, Henry S. R.; Zhang, Manlin; Lam, Stewart P. W.; Wang, Wei

    2013-01-01

    Chinese calligraphy has been scientifically investigated within the contexts and principles of psychology, cognitive science, and the cognitive neuroscience. On the basis of vast amount of research in the last 30 years, we have developed a cybernetic theory of handwriting and calligraphy to account for the intricate interactions of several psychological dimensions involved in the dynamic act of graphic production. Central to this system of writing are the role of sensory, bio-, cognitive, and neurofeedback mechanisms for the initiation, guidance, and regulation of the writing motions vis-a-vis visual-geometric variations of Chinese characters. This experiment provided the first evidence of cortical excitation in EEG theta wave as a neural hub that integrates information coming from changes in the practitioner's body, emotions, and cognition. In addition, it has also confirmed neurofeedback as an essential component of the cybernetic theory of handwriting and calligraphy. PMID:23533532

  4. EEG and Eye Tracking Demonstrate Vigilance Enhancement with Challenge Integration

    PubMed Central

    Bodala, Indu P.; Li, Junhua; Thakor, Nitish V.; Al-Nashash, Hasan

    2016-01-01

    Maintaining vigilance is possibly the first requirement for surveillance tasks where personnel are faced with monotonous yet intensive monitoring tasks. Decrement in vigilance in such situations could result in dangerous consequences such as accidents, loss of life and system failure. In this paper, we investigate the possibility to enhance vigilance or sustained attention using “challenge integration,” a strategy that integrates a primary task with challenging stimuli. A primary surveillance task (identifying an intruder in a simulated factory environment) and a challenge stimulus (periods of rain obscuring the surveillance scene) were employed to test the changes in vigilance levels. The effect of integrating challenging events (resulting from artificially simulated rain) into the task were compared to the initial monotonous phase. EEG and eye tracking data is collected and analyzed for n = 12 subjects. Frontal midline theta power and frontal theta to parietal alpha power ratio which are used as measures of engagement and attention allocation show an increase due to challenge integration (p < 0.05 in each case). Relative delta band power of EEG also shows statistically significant suppression on the frontoparietal and occipital cortices due to challenge integration (p < 0.05). Saccade amplitude, saccade velocity and blink rate obtained from eye tracking data exhibit statistically significant changes during the challenge phase of the experiment (p < 0.05 in each case). From the correlation analysis between the statistically significant measures of eye tracking and EEG, we infer that saccade amplitude and saccade velocity decrease with vigilance decrement along with frontal midline theta and frontal theta to parietal alpha ratio. Conversely, blink rate and relative delta power increase with vigilance decrement. However, these measures exhibit a reverse trend when challenge stimulus appears in the task suggesting vigilance enhancement. Moreover, the mean

  5. A theory of alpha/theta neurofeedback, creative performance enhancement, long distance functional connectivity and psychological integration.

    PubMed

    Gruzelier, John

    2009-02-01

    Professionally significant enhancement of music and dance performance and mood has followed training with an EEG-neurofeedback protocol which increases the ratio of theta to alpha waves using auditory feedback with eyes closed. While originally the protocol was designed to induce hypnogogia, a state historically associated with creativity, the outcome was psychological integration, while subsequent applications focusing on raising the theta-alpha ratio, reduced depression and anxiety in alcoholism and resolved post traumatic stress syndrome (PTSD). In optimal performance studies we confirmed associations with creativity in musical performance, but effects also included technique and communication. We extended efficacy to dance and social anxiety. Diversity of outcome has a counterpart in wide ranging associations between theta oscillations and behaviour in cognitive and affective neuroscience: in animals with sensory-motor activity in exploration, effort, working memory, learning, retention and REM sleep; in man with meditative concentration, reduced anxiety and sympathetic autonomic activation, as well as task demands in virtual spatial navigation, focussed and sustained attention, working and recognition memory, and having implications for synaptic plasticity and long term potentiation. Neuroanatomical circuitry involves the ascending mescencephalic-cortical arousal system, and limbic circuits subserving cognitive as well as affective/motivational functions. Working memory and meditative bliss, representing cognitive and affective domains, respectively, involve coupling between frontal and posterior cortices, exemplify a role for theta and alpha waves in mediating the interaction between distal and widely distributed connections. It is posited that this mediation in part underpins the integrational attributes of alpha-theta training in optimal performance and psychotherapy, creative associations in hypnogogia, and enhancement of technical, communication and

  6. Ramanujan’s mock theta functions

    PubMed Central

    Griffin, Michael; Ono, Ken; Rolen, Larry

    2013-01-01

    In his famous deathbed letter, Ramanujan introduced the notion of a mock theta function, and he offered some alleged examples. Recent work by Zwegers [Zwegers S (2001) Contemp Math 291:268–277 and Zwegers S (2002) PhD thesis (Univ of Utrecht, Utrecht, The Netherlands)] has elucidated the theory encompassing these examples. They are holomorphic parts of special harmonic weak Maass forms. Despite this understanding, little attention has been given to Ramanujan’s original definition. Here, we prove that Ramanujan’s examples do indeed satisfy his original definition. PMID:23536292

  7. Loss of balance during balance beam walking elicits a multifocal theta band electrocortical response

    PubMed Central

    Gwin, Joseph T.; Makeig, Scott; Ferris, Daniel P.

    2013-01-01

    Determining the neural correlates of loss of balance during walking could lead to improved clinical assessment and treatment for individuals predisposed to falls. We used high-density electroencephalography (EEG) combined with independent component analysis (ICA) to study loss of balance during human walking. We examined 26 healthy young subjects performing heel-to-toe walking on a treadmill-mounted balance beam as well as walking on the treadmill belt (both at 0.22 m/s). ICA identified clusters of electrocortical EEG sources located in or near anterior cingulate, anterior parietal, superior dorsolateral-prefrontal, and medial sensorimotor cortex that exhibited significantly larger mean spectral power in the theta band (4–7 Hz) during walking on the balance beam compared with treadmill walking. Left and right sensorimotor cortex clusters produced significantly less power in the beta band (12–30 Hz) during walking on the balance beam compared with treadmill walking. For each source cluster, we also computed a normalized mean time/frequency spectrogram time locked to the gait cycle during loss of balance (i.e., when subjects stepped off the balance beam). All clusters except the medial sensorimotor cluster exhibited a transient increase in theta band power during loss of balance. Cluster spectrograms demonstrated that the first electrocortical indication of impending loss of balance occurred in the left sensorimotor cortex at the transition from single support to double support prior to stepping off the beam. These findings provide new insight into the neural correlates of walking balance control and could aid future studies on elderly individuals and others with balance impairments. PMID:23926037

  8. Loss of balance during balance beam walking elicits a multifocal theta band electrocortical response.

    PubMed

    Sipp, Amy R; Gwin, Joseph T; Makeig, Scott; Ferris, Daniel P

    2013-11-01

    Determining the neural correlates of loss of balance during walking could lead to improved clinical assessment and treatment for individuals predisposed to falls. We used high-density electroencephalography (EEG) combined with independent component analysis (ICA) to study loss of balance during human walking. We examined 26 healthy young subjects performing heel-to-toe walking on a treadmill-mounted balance beam as well as walking on the treadmill belt (both at 0.22 m/s). ICA identified clusters of electrocortical EEG sources located in or near anterior cingulate, anterior parietal, superior dorsolateral-prefrontal, and medial sensorimotor cortex that exhibited significantly larger mean spectral power in the theta band (4-7 Hz) during walking on the balance beam compared with treadmill walking. Left and right sensorimotor cortex clusters produced significantly less power in the beta band (12-30 Hz) during walking on the balance beam compared with treadmill walking. For each source cluster, we also computed a normalized mean time/frequency spectrogram time locked to the gait cycle during loss of balance (i.e., when subjects stepped off the balance beam). All clusters except the medial sensorimotor cluster exhibited a transient increase in theta band power during loss of balance. Cluster spectrograms demonstrated that the first electrocortical indication of impending loss of balance occurred in the left sensorimotor cortex at the transition from single support to double support prior to stepping off the beam. These findings provide new insight into the neural correlates of walking balance control and could aid future studies on elderly individuals and others with balance impairments.

  9. A Matter of Time: The Influence of Recording Context on EEG Spectral Power in Adolescents and Young Adults with ADHD.

    PubMed

    Kitsune, Glenn L; Cheung, Celeste H M; Brandeis, Daniel; Banaschewski, Tobias; Asherson, Philip; McLoughlin, Gráinne; Kuntsi, Jonna

    2015-07-01

    Elevated theta or theta/beta ratio is often reported in attention deficit hyperactivity disorder (ADHD), but the consistency across studies and the relation to hypoarousal are increasingly questioned. Reports of elevated delta related to maturational lag and of attenuated beta activity are less well replicated. Some critical inconsistencies could relate to differences in recording context. We examined if resting-state EEG power or global field synchronization (GFS) differed between recordings made at the beginning and end of a 1.5 h testing session in 76 adolescents and young adults with ADHD, and 85 controls. In addition, we aimed to examine the effect of IQ on any potential group differences. Both regional and midline electrodes yielded group main effects for delta, trends in theta, but no differences in alpha or theta/beta ratio. An additional group difference in beta was detected when using regions. Group by time interactions in delta and theta became significant when controlling for IQ. The ADHD group had higher delta and theta power at time-1, but not at time-2, whereas beta power was elevated only at time-2. GFS did not differ between groups or condition. We show some ADHD-control differences on EEG spectral power varied with recording time within a single recording session, with both IQ and electrode selection having a small but significant influence on observed differences. Our findings demonstrate the effect of recording context on resting-state EEG, and highlight the importance of accounting for these variables to ensure consistency of results in future studies.

  10. Long-term EEG in adults: sleep-deprived EEG (SDE), ambulatory EEG (Amb-EEG) and long-term video-EEG recording (LTVER).

    PubMed

    Michel, V; Mazzola, L; Lemesle, M; Vercueil, L

    2015-03-01

    Long-term EEG in adults includes three modalities: sleep deprived-EEG lasting 1 to 3 hours, 24 hours ambulatory-EEG and continuous prolonged video-EEG lasting from several hours to several days. The main indications of long-term EEG are: syndromic classification of epilepsy; search for interictal discharges when epilepsy is suspected or for the purpose of therapeutic evaluation; positive diagnosis of paroxysmal clinical events; and pre-surgical evaluation of drug-resistant epilepsy. Sleep deprived-EEG and ambulatory-EEG are indicated to detect interictal discharges in order to validate a syndromic classification of epilepsy when standard EEG is negative. These exams can help in evaluating treatment efficacy, especially when clinical evaluation is difficult. Long-term video EEG is indicated for drug-resistant epilepsy, to analyze electro-clinical correlations in a pre-surgical evaluation context, and to refine a positive diagnosis when paroxysmal clinical events are frequent.

  11. [Post-radiation effect on the interhemispheric asymmetry in EEG and thermography characteristics].

    PubMed

    Zhavoronkova, L A; Gabova, A V; Kuznetsova, G D; Sel'skiĭ, A G; Pasechnik, V I; Kholodova, N B; Ianovich, A V

    2003-01-01

    Complex analysis of EEG and thermographic parameters carried out in 10 healthy subjects and 34 patients, Chernobyl clean-up participants revealed a correlation between EEG and brain temperature changes in the baseline state and during mental arithmetic. During cognitive activity the maximal increase in the average EEG coherence and temperature shifts in healthy subjects were observed in the left frontotemporal and right parietotemporal areas. In patients changes in both parameters under study were most pronounced, the interhemispheric relations were impaired. The visual analysis revealed "flat" and "hypersynchronous" EEG types in patients. The dominant pathologic activity in the betal range indicative of mediobasal and oral brainstem lesions was characteristic of the flat EEG. This type of activity was observed in 60% of patients. In these cases, a general decrease in EEG coherence and temperature was most pronounced in the left hemisphere. The hypersynchronou EEG type (40% patients) was characterized by paroxysmal activity in the theta and alpha ranges suggesting diencephalic brain lesions. In these cases, EEG coherence and temperature were more variable; changes in the right hemisphere were significant, be it increase or decrease. Our complex approach to investigation of brain activity in different aspects seems to be promising in estimation of the brain functional state both in healthy persons and patients in remote terms after exposure to radiation. The specific hemispheric temperature changes revealed in Chernobyl patients especially during cognitive activity can be the sequels of postradiation disorders of vascular neuro-circulation. The EEG findings suggest subcortical disorders at different levels (diencephalic or brainstem) and functional failure of the right or left hemispheres in remote terms after exposure to radiation.

  12. Prestimulus EEG amplitude determinants of ERP responses in a habituation paradigm.

    PubMed

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

    2013-09-01

    Evidence for the nature and extent of the prestimulus EEG contributions to ERP determination has been mounting, and we have recently mapped these within an equiprobable auditory Go/NoGo task. Here we examined if the pattern of relationships in the Go/NoGo would generalise to an auditory habituation paradigm. Count and No-task conditions were assessed, and we predicted broadly corresponding effects between Go and Count, and NoGo and No-task conditions. Single-trial data were obtained at the midline sites (Fz, Cz, Pz). Prestimulus EEG in each of the traditional bands was quantified using a sliding FFT window, and five ERP components were manually identified. The corresponding EEG and ERP data were then correlated across subjects, sites, and trials, separately for each ERP component measure (amplitude, latency), task condition (Count, No-task), and EEG band (delta, theta, alpha, beta). Despite the substantial paradigm and methodological differences, 10 of the 17 expected prestimulus EEG-ERP directional relationships (i.e., direct or inverse effects) were confirmed across the traditional bands and ERP components, and only one was in the opposite direction. Importantly, 18 additional relationships reached significance here; these occurred across the EEG bands, and ERP components. Together these findings confirm the significant contributions of prestimulus EEG to subsequent ERP responses. These appear to be at least partially independent of the paradigm and EEG methodology employed, suggesting that there is merit in mapping these contributions further. Our findings also indicate the improved sensitivity of the statistical approach used here in detecting such EEG-ERP relationships.

  13. Variability of model-free and model-based quantitative measures of EEG.

    PubMed

    Van Albada, Sacha J; Rennie, Christopher J; Robinson, Peter A

    2007-06-01

    Variable contributions of state and trait to the electroencephalographic (EEG) signal affect the stability over time of EEG measures, quite apart from other experimental uncertainties. The extent of intraindividual and interindividual variability is an important factor in determining the statistical, and hence possibly clinical significance of observed differences in the EEG. This study investigates the changes in classical quantitative EEG (qEEG) measures, as well as of parameters obtained by fitting frequency spectra to an existing continuum model of brain electrical activity. These parameters may have extra variability due to model selection and fitting. Besides estimating the levels of intraindividual and interindividual variability, we determined approximate time scales for change in qEEG measures and model parameters. This provides an estimate of the recording length needed to capture a given percentage of the total intraindividual variability. Also, if more precise time scales can be obtained in future, these may aid the characterization of physiological processes underlying various EEG measures. Heterogeneity of the subject group was constrained by testing only healthy males in a narrow age range (mean = 22.3 years, sd = 2.7). Eyes-closed EEGs of 32 subjects were recorded at weekly intervals over an approximately six-week period, of which 13 subjects were followed for a year. QEEG measures, computed from Cz spectra, were powers in five frequency bands, alpha peak frequency, and spectral entropy. Of these, theta, alpha, and beta band powers were most reproducible. Of the nine model parameters obtained by fitting model predictions to experiment, the most reproducible ones quantified the total power and the time delay between cortex and thalamus. About 95% of the maximum change in spectral parameters was reached within minutes of recording time, implying that repeat recordings are not necessary to capture the bulk of the variability in EEG spectra.

  14. Handedness leads to interhemispheric EEG asymmetry during sleep in the rat.

    PubMed

    Vyazovskiy, V V; Tobler, I

    2008-02-01

    Sleep electroencephalographic (EEG) slow-wave activity is increased after wakefulness and decreases during sleep. Regional sleep EEG differences are thought to be a consequence of activation of specific cortical neuronal circuits during waking. We investigated the relationship between handedness and interhemispheric brain asymmetry. Bilateral EEG recordings were obtained from the frontal and occipital cortex in rats with a clear paw preference in a food-reaching task (right, n = 5; left, n = 5). While still naïve to the task, no waking or sleep EEG asymmetry was present. During the food-reaching task, the waking EEG showed significant, substantial power increases in the frontal hemisphere contralateral to the dominant paw in the low theta range (4.5-6.0 Hz). Moreover, the non-REM sleep EEG following feeding bouts was markedly asymmetric, with significantly higher power in the hemisphere contralateral to the preferred paw in frequencies >1.5 Hz. No asymmetry was evident in the occipital EEG. Correlation analyses revealed a positive association between the hemispheric asymmetry during sleep and the degree of preferred use of the contralateral paw during waking in frequencies <9.0 Hz. Our findings show that handedness is reflected in specific, regional EEG asymmetry during sleep. Neuronal activity induced by preferential use of a particular forelimb led to a local enhancement of EEG power in frequencies within the delta and sigma ranges, supporting the hypothesis of use-dependent local sleep regulation. We conclude that inherent laterality is manifested when animals are exposed to complex behavioral tasks, and sleep plays a role in consolidating the hemispheric dominance of the brain.

  15. Functional connectivity among multi-channel EEGs when working memory load reaches the capacity.

    PubMed

    Zhang, Dan; Zhao, Huipo; Bai, Wenwen; Tian, Xin

    2016-01-15

    Evidence from behavioral studies has suggested a capacity existed in working memory. As the concept of functional connectivity has been introduced into neuroscience research in the recent years, the aim of this study is to investigate the functional connectivity in the brain when working memory load reaches the capacity. 32-channel electroencephalographs (EEGs) were recorded for 16 healthy subjects, while they performed a visual working memory task with load 1-6. Individual working memory capacity was calculated according to behavioral results. Short-time Fourier transform was used to determine the principal frequency band (theta band) related to working memory. The functional connectivity among EEGs was measured by the directed transform function (DTF) via spectral Granger causal analysis. The capacity was 4 calculated from the behavioral results. The power was focused in the frontal midline region. The strongest connectivity strengths of EEG theta components from load 1 to 6 distributed in the frontal midline region. The curve of DTF values vs load numbers showed that DTF increased from load 1 to 4, peaked at load 4, then decreased after load 4. This study finds that the functional connectivity between EEGs, described quantitatively by DTF, became less strong when working memory load exceeded the capacity.

  16. Trait anxiety impact on posterior activation asymmetries at rest and during evoked negative emotions: EEG investigation.

    PubMed

    Aftanas, Ljubomir I; Pavlov, Sergey V

    2005-01-01

    The main objective of the present investigation was to examine how high trait anxiety would influence cortical EEG asymmetries under non-emotional conditions and while experiencing negative emotions. The 62-channel EEG was recorded in control (n=21) and high anxiety (HA, n=18) non-patient individuals. Results showed that in HA subjects, the lowest level of arousal (eyes closed) was associated with stronger right-sided parieto-temporal theta-1 (4-6 Hz) and beta-1 (12-18 Hz) activity, whereas increased non-emotional arousal (eyes open, viewing neutral movie clip) was marked by persisting favored right hemisphere beta-1 activity. In turn, viewing aversive movie clip by the HA group led to significant lateralized decrease of the right parieto-temporal beta-1 power, which was initially higher in the emotionally neutral conditions. The EEG data suggests that asymmetrical parieto-temporal theta-1 and beta-1 EEG activity might be better interpreted in terms of Gray's BAS and BIS theory.

  17. Reduced ERPs and theta oscillations underlie working memory deficits in Toxoplasma gondii infected seniors.

    PubMed

    Gajewski, Patrick D; Falkenstein, Michael; Hengstler, Jan G; Golka, Klaus

    2016-10-01

    Toxoplasma gondii is one of the most widespread infections in humans. Recent studies give evidence for memory deficits in infected older adults. To investigate working memory dysfunction in infected elderly, a double-blinded electrophysiological study was conducted. 84 persons derived from a sample of 131 healthy participants with the mean age of 70 years were assigned to two groups of 42 non-infected and 42 infected individuals. The outcome measures were behavioral performance, target and response-related ERPs, and time-frequency wavelets during performance in a n-back working-memory task. The infected individuals showed a reduced rate of detected targets and diminished P3b amplitude both in target-locked as well as response-locked data compared to the non-infected group. Time-frequency decomposition of the EEG-signals revealed lower evoked power in the theta frequency range in the target-locked as well as in the response-locked data in infected individuals. The reported effects were comparable with differences between healthy young and old adults described previously. Taking together, the reduced working-memory performance accompanied by an attenuated P3b and frontal theta activity may suggest neurotransmitter imbalance like dopamine and norepinephrine in T. gondii infected individuals. In face of a high prevalence of T. gondii infection and the increasing ratio of older population their accelerated memory decline may have substantial socioeconomic consequences.

  18. Recalling and forgetting dreams: theta and alpha oscillations during sleep predict subsequent dream recall.

    PubMed

    Marzano, Cristina; Ferrara, Michele; Mauro, Federica; Moroni, Fabio; Gorgoni, Maurizio; Tempesta, Daniela; Cipolli, Carlo; De Gennaro, Luigi

    2011-05-04

    Under the assumption that dream recall is a peculiar form of declarative memory, we have hypothesized that (1) the encoding of dream contents during sleep should share some electrophysiological mechanisms with the encoding of episodic memories of the awake brain and (2) recalling a dream(s) after awakening from non-rapid eye movement (NREM) and rapid eye movement (REM) sleep should be associated with different brain oscillations. Here, we report that cortical brain oscillations of human sleep are predictive of successful dream recall. In particular, after morning awakening from REM sleep, a higher frontal 5-7 Hz (theta) activity was associated with successful dream recall. This finding mirrors the increase in frontal theta activity during successful encoding of episodic memories in wakefulness. Moreover, in keeping with the different EEG background, a different predictive relationship was found after awakening from stage 2 NREM sleep. Specifically, a lower 8-12 Hz (alpha) oscillatory activity of the right temporal area was associated with a successful dream recall. These findings provide the first evidence of univocal cortical electroencephalographic correlates of dream recall, suggesting that the neurophysiological mechanisms underlying the encoding and recall of episodic memories may remain the same across different states of consciousness.

  19. The neuronal mechanisms underlying improvement of impulsivity in ADHD by theta/beta neurofeedback

    PubMed Central

    Bluschke, Annet; Broschwitz, Felicia; Kohl, Simon; Roessner, Veit; Beste, Christian

    2016-01-01

    Neurofeedback is increasingly recognized as an intervention to treat core symptoms of attention deficit hyperactivity disorder (ADHD). Despite the large number of studies having been carried out to evaluate its effectiveness, it is widely elusive what neuronal mechanisms related to the core symptoms of ADHD are modulated by neurofeedback. 19 children with ADHD undergoing 8 weeks of theta/beta neurofeedback and 17 waiting list controls performed a Go/Nogo task in a pre-post design. We used neurophysiological measures combining high-density EEG recording with source localization analyses using sLORETA. Compared to the waiting list ADHD control group, impulsive behaviour measured was reduced after neurofeedback treatment. The effects of neurofeedback were very specific for situations requiring inhibitory control over responses. The neurophysiological data shows that processes of perceptual gating, attentional selection and resource allocation processes were not affected by neurofeedback. Rather, neurofeedback effects seem to be based on the modulation of response inhibition processes in medial frontal cortices. The study shows that specific neuronal mechanisms underlying impulsivity are modulated by theta/beta neurofeedback in ADHD. The applied neurofeedback protocol could be particularly suitable to address inhibitory control. The study validates assumed functional neuroanatomical target regions of an established neurofeedback protocol on a neurophysiological level. PMID:27514985

  20. Frontal midline theta connectivity is related to efficiency of WM maintenance and is affected by aging.

    PubMed

    Tóth, Brigitta; Kardos, Zsófia; File, Bálint; Boha, Roland; Stam, Cornelis Jan; Molnár, Márk

    2014-10-01

    Representations in working memory (WM) are temporary, but can be refreshed for longer periods of time through maintenance mechanisms, thereby establishing their availability for subsequent memory tests. Frontal brain regions supporting WM maintenance operations undergo anatomical and functional changes with advancing age, leading to age related decline of memory functions. The present study focused on age-related functional connectivity changes of the frontal midline (FM) cortex in the theta band (4-8 Hz), related to WM maintenance. In the visual delayed-match-to-sample WM task young (18-26 years, N=20) and elderly (60-71 years N=16) adults had to memorize sample stimuli consisting of 3 or 5 items while 33 channel EEG recording was performed. The phase lag index was used to quantify connectivity strength between cortical regions. The low and high memory demanding WM maintenance periods were classified based on whether they were successfully maintained (remembered) or unsuccessfully maintained (unrecognized later). In the elderly reduced connectivity strength of FM brain region and decreased performance were observed. The connectivity strength between FM and posterior sensory cortices was shown to be sensitive to both increased memory demands and memory performance regardless of age. The coupling of frontal regions (midline and lateral) and FM-temporal cortices characterized successfully maintained trials and declined with advancing age. The findings provide evidence that a FM neural circuit of theta oscillations that serves a possible basis of active maintenance process is especially vulnerable to aging.

  1. Neuroelectric assessment of HIV: EEG, ERP, and viral load.

    PubMed

    Polich, J; Ilan, A; Poceta, J S; Mitler, M M; Darko, D F

    2000-10-01

    The effects of the human immunodeficiency virus (HIV) infection on the central nervous system function were studied with electroencephalographic (EEG) and auditory event-related brain potentials (EPRs) in patients infected with HIV and unaffected young adult control subjects (n=10/group). All subjects were assessed once every 15 min for four trial blocks at the same time of day to assess EEG/ERP changes with time on task-induced fatigue. Spectral analysis was applied to the pre- and post-stimulus EEG segments. ERP values were evaluated with respect to group differences for component amplitude and latency measures. Spectral analysis demonstrated that HIV patients evinced greater pre-stimulus delta power over frontal areas compared to control subjects, and less post-stimulus spectral power for the delta, theta, and alpha bands over the central/parietal areas. P300 amplitude was smaller, and latency was marginally longer for the HIV patients compared to control subjects. P300 latency correlated positively with increases in the patient HIV viral load. Time-on-task generally did not affect EEG or ERP measures for either group other than contributing to an overall decrease in neuroelectric responsivity. Group spectral power effects were consistent with differences in arousal/fatigue level. P300 group differences were consistent with declines in cognitive capability, and P300 latency increased with increased viral load. HIV infection negatively affected central nervous system function as measured by EEG and cognitive ERPs in a manner that suggests decreased arousal and increased fatigue in HIV patients.

  2. [EEG and ischemic stroke in full-term newborns].

    PubMed

    Selton, D; André, M; Hascoët, J M

    2003-06-01

    The aims of this study were to describe EEG anomalies in unilateral neonatal ischemic stroke without hypoxic-ischemic encephalopathy, and to determine possible links between these abnormalities and long-term outcome. In 6 full-term newborns without severe fetal distress ischemic stroke was confirmed by computed tomography and/or magnetic resonance imaging. Twenty EEGs were recorded during the neonatal period, 5 in acute stage and 15 later. The duration of the follow-up ranged from 3 to 9 years. All newborns developed unilateral clonic seizures, right-sided (5 cases) or left-sided (1 case); seizures began between 14 and 48 h of life. At follow-up, 3 children were normal at 2 and 6 years of age, while the 3 others had sequelae: epilepsy at 9 years of age in one, and unilateral mild cerebral palsy in the 2 others (3 and 4 years of age), with behavioral problems in one of them. Critical EEG discharges, rhythmic sharp waves and/or slow waves were recorded on the injured side. Abnormalities of interictal activity were excess of alpha or theta rhythms, transitory EEG discontinuity or low voltage. The 2 children with cerebral palsy had numerous unilateral post-ictal positive rolandic slow sharp waves (PRSSWs), which were similar to the positive rolandic sharp waves of premature infants; the child with behavioral problems had numerous positive left-sided temporal fast sharp waves. PRSSWs could be associated with contralateral motor sequelae, while positive left temporal fast sharp waves were associated with long term behavioral problems. These findings may be used for future prospective studies aimed at specifying the relation between EEG abnormalities and long-term outcome.

  3. Frontal theta activation associated with error detection in toddlers: influence of familial socioeconomic status.

    PubMed

    Conejero, Ángela; Guerra, Sonia; Abundis-Gutiérrez, Alicia; Rueda, M Rosario

    2016-12-15

    Error detection is one of the functions of the executive attention network, a brain system involved in executive control that includes the anterior cingulate cortex and other prefrontal regions. Despite the key role of this function in a wide range of life outcomes, very limited research has examined the early development of the network and whether its functional efficacy is related to environmental factors. Electrophysiological studies with adults have shown oscillatory activity in theta (4-7 Hz) range arising from medial frontal cortex that follows the detection of self-committed or observed errors. In the current study, we designed a novel experimental procedure that involved a familiarization phase with simple three-pieces puzzles followed by an experimental phase in which toddlers observed the puzzles being formed either correctly or incorrectly. Observation of incorrect configurations produced increased potentials in midline channels and greater power theta activity for both toddlers (n = 56) and adults (n = 14). In addition, socioeconomic status of the family in general, and parental education in particular, contributed to individual differences in the amplitude of the error-related signal and associated theta power in toddlers, indicating that children raised in lower SES families show poorer activation of the executive attention network. These data demonstrate the influence of environmental factors at the earliest stages of development of the executive attention network. Importantly, the results show that error-detection EEG signals can be used as neural markers of the initial development of executive attention, which can be of great help for the early detection of risk for developmental disorders involving deficits in this function.

  4. Event-related theta synchronization predicts deficit in facial affect recognition in schizophrenia.

    PubMed

    Csukly, Gábor; Stefanics, Gábor; Komlósi, Sarolta; Czigler, István; Czobor, Pál

    2014-02-01

    Growing evidence suggests that abnormalities in the synchronized oscillatory activity of neurons in schizophrenia may lead to impaired neural activation and temporal coding and thus lead to neurocognitive dysfunctions, such as deficits in facial affect recognition. To gain an insight into the neurobiological processes linked to facial affect recognition, we investigated both induced and evoked oscillatory activity by calculating the Event Related Spectral Perturbation (ERSP) and the Inter Trial Coherence (ITC) during facial affect recognition. Fearful and neutral faces as well as nonface patches were presented to 24 patients with schizophrenia and 24 matched healthy controls while EEG was recorded. The participants' task was to recognize facial expressions. Because previous findings with healthy controls showed that facial feature decoding was associated primarily with oscillatory activity in the theta band, we analyzed ERSP and ITC in this frequency band in the time interval of 140-200 ms, which corresponds to the N170 component. Event-related theta activity and phase-locking to facial expressions, but not to nonface patches, predicted emotion recognition performance in both controls and patients. Event-related changes in theta amplitude and phase-locking were found to be significantly weaker in patients compared with healthy controls, which is in line with previous investigations showing decreased neural synchronization in the low frequency bands in patients with schizophrenia. Neural synchrony is thought to underlie distributed information processing. Our results indicate a less effective functioning in the recognition process of facial features, which may contribute to a less effective social cognition in schizophrenia.

  5. 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.

  6. [Computerized EEG and personality].

    PubMed

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

    1989-01-01

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

  7. EEG synchronization and migraine

    NASA Astrophysics Data System (ADS)

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

    2004-03-01

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

  8. Flexible electroencephalogram (EEG) headband

    NASA Technical Reports Server (NTRS)

    Raggio, L. J.

    1973-01-01

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

  9. Combination of frequency bands in EEG for feature reduction in mental task classification.

    PubMed

    Abdollahi, Farnaz; Motie-Nasrabadi, Ali

    2006-01-01

    Brain-computer interfaces require online processing of electroencephalogram (EEG) measurements. Therefore, speed of signal processing is of great importance in BCI systems. We present a method of feature reduction by combining frequency band powers of EEG, in order to speed up processing and meanwhile avoid classifier overfitting. As a result a linear combination of power spectrum of EEG frequency bands (alpha, beta, gamma, delta & theta) was found that reduces the dimension of feature vector by a factor of 5. This method gives a total correct classification rate of 91.71% comparing to 87.96% achieved from direct use of frequency band powers and 85.54% achieved from PCA feature reduction method applied to the same feature vector with 14 components.

  10. Drug-induced EEG pattern predicts effectiveness of ketamine in treating refractory status epilepticus.

    PubMed

    Basha, Maysaa M; Alqallaf, Abdulradha; Shah, Aashit K

    2015-04-01

    Refractory status epilepticus (RSE) can lack overt clinical manifestation and is usually treated with continuous infusion of intravenous anesthetic drugs (IVADs), where the use of continuous electroencephalography (cEEG) is imperative. Ketamine has recently been shown to be effective in the treatment of RSE. We retrospectively review a cohort of 11 patients receiving ketamine as part of their treatment regimen for RSE. We report on the presence of a characteristic EEG rhythm consisting of a generalized archiform theta to beta rhythms (7-20 Hz) appearing after ketamine administration. This pattern was seen in five patients, four of whom achieved successful resolution of RSE. Ketamine-induced EEG pattern may serve as a biomarker predictive of successful treatment outcome in RSE.

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

    PubMed

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

    2015-09-01

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

  12. Complexity of resting-state EEG activity in the patients with early-stage Parkinson's disease.

    PubMed

    Yi, Guo-Sheng; Wang, Jiang; Deng, Bin; Wei, Xi-Le

    2017-04-01

    To investigate the abnormal brain activities in the early stage of Parkinson's disease (PD), the electroencephalogram (EEG) signals were recorded with 20 channels from non-dementia PD patients (18 patients, 8 females) and age matched healthy controls (18 subjects, 8 females) during the resting state. Two methods based on the ordinal patterns of the recorded series, i.e., permutation entropy (PE) and order index (OI), were introduced to characterize the complexity of the cortical activities for two groups. It was observed that the resting-state EEG of PD patients showed lower PE and higher OI than healthy controls, which indicated that the early-stage PD caused the reduced complexity of EEG. We further applied two methods to determine the complexity of EEG rhythms in five sub-bands. The results showed that the gamma, beta and alpha rhythms of PD patients were characterized by lower PE and higher OI, i.e., reduced complexity, than healthy subjects. No significant differences were observed in theta or delta rhythms between two groups. The findings suggested that PE and OI were promising methods to detect the abnormal changes in the dynamics of EEG signals associated with early-stage PD. Further, such changes in EEG complexity may be the early markers of the cortical or subcortical dysfunction caused by PD.

  13. Theoretical analysis on relationship between the neural activity and the EEG.

    PubMed

    Kitazoe, Y; Hiraoka, N; Ueta, H; Ogura, H; Yamamoto, K; Seto, K; Saito, H

    1983-10-21

    Firstly, a collective oscillation mode of the neural activity is derived from the neural network system by using the multicompartment equation and the projection operator technique. This technique takes into account higher order interactions among neurons. The solution of the equation gives a chain structure with an infinite number of circuit loops in which each of them is only composed of four neurons. The obtained eigenvalues are quite similar to the spectrum of frequencies of the EEG. Secondly, the time-dependent behavior of the observed EEG is simulated by starting from the elementary process of action potential trains of neurons, which includes the effect of the collective oscillation mode mentioned above. This gives a comprehensive derivation of the EEG from the neural activity of action potentials. The simulation assumes that information of the action potential trains can be transmitted to the EEG through the intermediate states of the postsynaptic potential trains and the slow waves. The paper reports that a slightly modulated activity of a relatively small amount of neurons can cause a strong influence on the shape of the global EEG and that the calculated results reproduce the characteristic features of the EEG in a rat such as the theta rhythm, the spindle wave and the arousal wave.

  14. BLINKER: Automated Extraction of Ocular Indices from EEG Enabling Large-Scale Analysis.

    PubMed

    Kleifges, Kelly; Bigdely-Shamlo, Nima; Kerick, Scott E; Robbins, Kay A

    2017-01-01

    Electroencephalography (EEG) offers a platform for studying the relationships between behavioral measures, such as blink rate and duration, with neural correlates of fatigue and attention, such as theta and alpha band power. Further, the existence of EEG studies covering a variety of subjects and tasks provides opportunities for the community to better characterize variability of these measures across tasks and subjects. We have implemented an automated pipeline (BLINKER) for extracting ocular indices such as blink rate, blink duration, and blink velocity-amplitude ratios from EEG channels, EOG channels, and/or independent components (ICs). To illustrate the use of our approach, we have applied the pipeline to a large corpus of EEG data (comprising more than 2000 datasets acquired at eight different laboratories) in order to characterize variability of certain ocular indicators across subjects. We also investigate dependence of ocular indices on task in a shooter study. We have implemented our algorithms in a freely available MATLAB toolbox called BLINKER. The toolbox, which is easy to use and can be applied to collections of data without user intervention, can automatically discover which channels or ICs capture blinks. The tools extract blinks, calculate common ocular indices, generate a report for each dataset, dump labeled images of the individual blinks, and provide summary statistics across collections. Users can run BLINKER as a script or as a plugin for EEGLAB. The toolbox is available at https://github.com/VisLab/EEG-Blinks. User documentation and examples appear at http://vislab.github.io/EEG-Blinks/.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  16. BLINKER: Automated Extraction of Ocular Indices from EEG Enabling Large-Scale Analysis

    PubMed Central

    Kleifges, Kelly; Bigdely-Shamlo, Nima; Kerick, Scott E.; Robbins, Kay A.

    2017-01-01

    Electroencephalography (EEG) offers a platform for studying the relationships between behavioral measures, such as blink rate and duration, with neural correlates of fatigue and attention, such as theta and alpha band power. Further, the existence of EEG studies covering a variety of subjects and tasks provides opportunities for the community to better characterize variability of these measures across tasks and subjects. We have implemented an automated pipeline (BLINKER) for extracting ocular indices such as blink rate, blink duration, and blink velocity-amplitude ratios from EEG channels, EOG channels, and/or independent components (ICs). To illustrate the use of our approach, we have applied the pipeline to a large corpus of EEG data (comprising more than 2000 datasets acquired at eight different laboratories) in order to characterize variability of certain ocular indicators across subjects. We also investigate dependence of ocular indices on task in a shooter study. We have implemented our algorithms in a freely available MATLAB toolbox called BLINKER. The toolbox, which is easy to use and can be applied to collections of data without user intervention, can automatically discover which channels or ICs capture blinks. The tools extract blinks, calculate common ocular indices, generate a report for each dataset, dump labeled images of the individual blinks, and provide summary statistics across collections. Users can run BLINKER as a script or as a plugin for EEGLAB. The toolbox is available at https://github.com/VisLab/EEG-Blinks. User documentation and examples appear at http://vislab.github.io/EEG-Blinks/. PMID:28217081

  17. 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

  18. A statistical comparison of EEG time- and time-frequency domain representations of error processing.

    PubMed

    Munneke, Gert-Jan; Nap, Tanja S; Schippers, Eveline E; Cohen, Michael X

    2015-08-27

    Successful behavior relies on error detection and subsequent remedial adjustment of behavior. Researchers have identified two electrophysiological signatures of error processing: the time-domain error-related negativity (ERN), and the time-frequency domain increased power in the delta/theta frequency bands (~2-8 Hz). The relationship between these two signatures is not entirely clear: on the one hand they occur after the same type of event and with similar latency, but on the other hand, the time-domain ERP component contains only phase-locked activity whereas the time-frequency response additionally contains non-phase-locked dynamics. Here we examined the ERN and error-related delta/theta activity in relation to each other, focusing on within-subject analyses that utilize single-trial data. Using logistic regression, we constructed three statistical models in which the accuracy of each trial was predicted from the ERN, delta/theta power, or both. We found that both the ERN and delta/theta power worked roughly equally well as predictors of single-trial accuracy (~70% accurate prediction). Furthermore, a model including both measures provided a stronger overall prediction compared to either model alone. Based on these findings two conclusions are drawn: first, the phase-locked part of the EEG signal appears to be roughly as predictive of single-trial response accuracy as the non-phase-locked part; second, the single-trial ERP and delta/theta power contain both overlapping and independent information.

  19. White matter vascular lesions are related to parietal-to-frontal coupling of EEG rhythms in mild cognitive impairment.

    PubMed

    Babiloni, Claudio; Frisoni, Giovanni B; Pievani, Michela; Vecchio, Fabrizio; Infarinato, Francesco; Geroldi, Cristina; Salinari, Serenella; Ferri, Raffaele; Fracassi, Claudia; Eusebi, Fabrizio; Rossini, Paolo M

    2008-12-01

    Do cerebrovascular and Alzheimer's disease (AD) lesions represent additive factors in the development of mild cognitive impairment (MCI) as a putative preclinical stage of AD? Here we tested the hypothesis that directionality of fronto-parietal functional coupling of electroencephalographic (EEG) rhythms is relatively preserved in amnesic MCI subjects in whom the cognitive decline is mainly explained by white-matter vascular load. Resting EEG was recorded in 40 healthy elderly (Nold) and 78 amnesic MCI. In the MCI subjects, white-matter vascular load was quantified based on magnetic resonance images (0-30 visual rating scale). EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha1 (8-10.5 Hz), alpha2 (10.5-13 Hz), beta1 (13-20 Hz), and beta2 (20-30 Hz). Directionality of fronto-parietal functional coupling of EEG rhythms was estimated by directed transfer function software. As main results, (i) fronto-parietal functional coupling of EEG rhythms was higher in magnitude in the Nold than in the MCI subjects; (ii) more interestingly, that coupling was higher at theta, alpha1, alpha2, and beta1 in MCI V+ (high vascular load; N = 42; MMSE = 26) than in MCI V- group (low vascular load; N = 36; MMSE= 26.7). These results are interpreted as supporting the additive model according to which MCI state would result from the combination of cerebrovascular and neurodegenerative lesions.

  20. Synchronization of fronto-parietal beta and theta networks as a signature of visual awareness in neglect.

    PubMed

    Yordanova, Juliana; Kolev, Vasil; Verleger, Rolf; Heide, Wolfgang; Grumbt, Michael; Schürmann, Martin

    2017-02-01

    In the neglect syndrome, the perceptual deficit for contra-lesional hemi-space is increasingly viewed as a dysfunction of fronto-parietal cortical networks, the disruption of which has been described in neuroanatomical and hemodynamic studies. Here we exploit the superior temporal resolution of electroencephalography (EEG) to study dynamic transient connectivity of fronto-parietal circuits at early stages of visual perception in neglect. As reflected by inter-regional phase synchronization in a full-field attention task, two functionally distinct fronto-parietal networks, in beta (15-25Hz) and theta (4-8Hz) frequency bands, were related to stimulus discrimination within the first 200 ms of visual processing. Neglect pathology was specifically associated with significant suppressions of both beta and theta networks engaging right parietal regions. These connectivity abnormalities occurred in a pattern that was distinctly different from what was observed in right-hemisphere lesion patients without neglect. Also, both beta and theta abnormalities contributed additively to visual awareness decrease, quantified in the Behavioural Inattention Test. These results provide evidence for the impairment of fast dynamic fronto-parietal interactions during early stages of visual processing in neglect pathology. Also, they reveal that different modes of fronto-parietal dysfunction contribute independently to deficits in visual awareness at the behavioural level.

  1. [Gender differences in resting EEG related to Eysenk's Personality Traits].

    PubMed

    Razumnikova, O M

    2004-01-01

    EEG mapping was used to study gender differences in hemispheric organization related to personality (40 male and 42 female subjects, the students 17-20 ages). The results showed, that each clearly defined personality trait (neuroticism, extraversion, psychoticizm and social conformity) characterized by special EEG pattern differenced on men and women groups. At the same time, more close interaction of gender and neuroticism was observed, but gender and extraversion were less connected. Neuroticism related patterns of coherence in the alpha2- and beta2-bands were associated with an activity changes in anterior cortex in men but posterior--in women, at that the positive correlations were observed in the beta2-band in the former case and negative ones in the second. There are two opposing tendencies of the interaction between extraversion and gender in a modulation of the resting theta-rhythm: an increase of cortex connections in men and decrease ones in women. The specificity of spatial-temporal EEG patterns in men associated mostly with a psychoticizm value but in women--with a social conformism. In either case these personality traits related to activity of frontal cortex in the left hemisphere.

  2. Optogenetic Activation of Septal Glutamatergic Neurons Drive Hippocampal Theta Rhythms.

    PubMed

    Robinson, Jennifer; Manseau, Frédéric; Ducharme, Guillaume; Amilhon, Bénédicte; Vigneault, Erika; El Mestikawy, Salah; Williams, Sylvain

    2016-03-09

    The medial septum and diagonal band of Broca (MS-DBB) has an essential role for theta rhythm generation in the hippocampus and is critical for learning and memory. The MS-DBB contains cholinergic, GABAergic, and recently described glutamatergic neurons, but their specific contribution to theta generation is poorly understood. Here, we examined the role of MS-DBB glutamatergic neurons in theta rhythm using optogenetic activation and electrophysiological recordings performed in in vitro preparations and in freely behaving mice. The experiments in slices suggest that MS-DBB glutamatergic neurons provide prominent excitatory inputs to a majority of local GABAergic and a minority of septal cholinergic neurons. In contrast, activation of MS-DBB glutamatergic fiber terminals in hippocampal slices elicited weak postsynaptic responses in hippocampal neurons. In the in vitro septo-hippocampal preparation, activation of MS-DBB glutamatergic neurons did increase the rhythmicity of hippocampal theta oscillations, whereas stimulation of septo-hippocampal glutamatergic fibers in the fornix did not have an effect. In freely behaving mice, activation of these neurons in the MS-DBB strongly synchronized hippocampal theta rhythms over a wide range of frequencies, whereas activation of their projections to the hippocampus through fornix stimulations had no effect on theta rhythms, suggesting that MS-DBB glutamatergic neurons played a role in theta generation through local modulation of septal neurons. Together, these results provide the first evidence that MS-DBB glutamatergic neurons modulate local septal circuits, which in turn contribute to theta rhythms in the hippocampus.

  3. Hippocampo-cerebellar theta band phase synchrony in rabbits.

    PubMed

    Wikgren, J; Nokia, M S; Penttonen, M

    2010-02-17

    Hippocampal functioning, in the form of theta band oscillation, has been shown to modulate and predict cerebellar learning of which rabbit eyeblink conditioning is perhaps the most well-known example. The contribution of hippocampal neural activity to cerebellar learning is only possible if there is a functional connection between the two structures. Here, in the context of trace eyeblink conditioning, we show (1) that, in addition to the hippocampus, prominent theta oscillation also occurs in the cerebellum, and (2) that cerebellar theta oscillation is synchronized with that in the hippocampus. Further, the degree of phase synchrony (PS) increased both as a response to the conditioning stimuli and as a function of the relative power of hippocampal theta oscillation. However, the degree of PS did not change as a function of either training or learning nor did it predict learning rate as the hippocampal theta ratio did. Nevertheless, theta band synchronization might reflect the formation of transient neural assemblies between the hippocampus and the cerebellum. These findings help us understand how hippocampal function can affect eyeblink conditioning, during which the critical plasticity occurs in the cerebellum. Future studies should examine cerebellar unit activity in relation to hippocampal theta oscillations in order to discover the detailed mechanisms of theta-paced neural activity.

  4. Reversal of theta rhythm flow through intact hippocampal circuits.

    PubMed

    Jackson, Jesse; Amilhon, Bénédicte; Goutagny, Romain; Bott, Jean-Bastien; Manseau, Frédéric; Kortleven, Christian; Bressler, Steven L; Williams, Sylvain

    2014-10-01

    Activity flow through the hippocampus is thought to arise exclusively from unidirectional excitatory synaptic signaling from CA3 to CA1 to the subiculum. Theta rhythms are important for hippocampal synchronization during episodic memory processing; thus, it is assumed that theta rhythms follow these excitatory feedforward circuits. To the contrary, we found that theta rhythms generated in the rat subiculum flowed backward to actively modulate spike timing and local network rhythms in CA1 and CA3. This reversed signaling involved GABAergic mechanisms. However, when hippocampal circuits were physically limited to a lamellar slab, CA3 outputs synchronized CA1 and the subiculum using excitatory mechanisms, as predicted by classic hippocampal models. Finally, analysis of in vivo recordings revealed that this reversed theta flow was most prominent during REM sleep. These data demonstrate that communication between CA3, CA1 and the subiculum is not exclusively unidirectional or excitatory and that reversed inhibitory theta signaling also contributes to intrahippocampal synchrony.

  5. To Know or Not to Know? Theta and Delta Reflect Complementary Information about an Advanced Cue before Feedback in Decision-Making

    PubMed Central

    Wang, Jing; Chen, Zhaofeng; Peng, Xiaozhe; Yang, Tiantian; Li, Peng; Cong, Fengyu; Li, Hong

    2016-01-01

    To investigate brain activity during the reinforcement learning process in social contexts is a topic of increasing research interest. Previous studies have mainly focused on using electroencephalograms (EEGs) for feedback evaluation in reinforcement learning tasks by measuring event-related potentials. Few studies have investigated the time–frequency (TF) profiles of a cue that manifested whether a following feedback is available or not after decision-making. Moreover, it remains unclear whether the TF profiles of the cue interact with different agents to whom the feedback related. In this study we used the TF approach to test EEG oscillations of the cue stimuli in three agents (‘Self’, ‘Other’, and ‘Computer’) conditions separately. The results showed that the increased central-posterior delta power was elicited by the feedback unavailable cues more so than with the feedback available cue within 200–350 ms after the onset of the cue, but only in the self-condition. Moreover, a frontal-central theta oscillation had enhanced power when following the feedback unavailable cue as opposed to the feedback available cue across three agencies. These findings demonstrated that the cue for knowing an outcome produced reward prediction error-like signals, which were mirrored by the delta and theta oscillations during decision-making. More importantly, the present study demonstrated that the theta and delta oscillations reflected separable components of the advanced cue processing before the feedback in decision-making. PMID:27766090

  6. EEG analyses with SOBI.

    SciTech Connect

    Glickman, Matthew R.; Tang, Akaysha

    2009-02-01

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

  7. Impact of alcohol use on EEG dynamics of response inhibition: a cotwin control analysis.

    PubMed

    Harper, Jeremy; Malone, Stephen M; Iacono, William G

    2016-11-18

    Research indicates that alcohol misuse is associated with behavioral disinhibition, but the neurophysiological mechanisms governing this relationship remain largely unknown. Recent work suggests that successful inhibition and cognitive control involve electrophysiological theta-band dynamics, including medial frontal cortex (MFC) power enhancement and functional connectivity between the MFC and dorsal prefrontal cortex (dPFC) regions, which may be disrupted by alcohol misuse. In addition, research suggests that, compared to men, women are at heightened risk of experiencing the negative physical and neurocognitive correlates of drinking. The present study tested the hypothesis that alcohol misuse has a deleterious effect on theta-band response inhibition EEG dynamics in a sample of 300 24-year-old same-sex twins. A cotwin control (CTC) design was used to disentangle premorbid risk for alcohol use from the causal effects of alcohol exposure. Drinking was negatively associated with theta-band MFC power and MFC-dPFC connectivity during response inhibition, and this effect was stronger among women. The CTC analysis suggested that, for women, reduced nogo-related theta-band MFC power and MFC-dPFC connectivity were both consistent with the potential deleterious causal effects of alcohol exposure. These findings suggest that diminished theta-band MFC power and MFC-dPFC connectivity may be neurophysiological mechanisms underlying alcohol-related disinhibition. Although preliminary, these results suggest that normative levels of alcohol use during emerging adulthood have potential sex-specific causal effects on response inhibition EEG dynamics, and thus have potentially significant public health implications.

  8. Estimating brain load from the EEG.

    PubMed

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

    2009-07-14

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  11. Memory load effect in auditory-verbal short-term memory task: EEG fractal and spectral analysis.

    PubMed

    Stokić, Miodrag; Milovanović, Dragan; Ljubisavljević, Miloš R; Nenadović, Vanja; Čukić, Milena

    2015-10-01

    The objective of this preliminary study was to quantify changes in complexity of EEG using fractal dimension (FD) alongside linear methods of spectral power, event-related spectral perturbations, coherence, and source localization of EEG generators for theta (4-7 Hz), alpha (8-12 Hz), and beta (13-23 Hz) frequency bands due to a memory load effect in an auditory-verbal short-term memory (AVSTM) task for words. We examined 20 healthy individuals using the Sternberg's paradigm with increasing memory load (three, five, and seven words). The stimuli were four-letter words. Artifact-free 5-s EEG segments during retention period were analyzed. The most significant finding was the increase in FD with the increase in memory load in temporal regions T3 and T4, and in parietal region Pz, while decrease in FD with increase in memory load was registered in frontal midline region Fz. Results point to increase in frontal midline (Fz) theta spectral power, decrease in alpha spectral power in parietal region-Pz, and increase in beta spectral power in T3 and T4 region with increase in memory load. Decrease in theta coherence within right hemisphere due to memory load was obtained. Alpha coherence increased in posterior regions with anterior decrease. Beta coherence increased in fronto-temporal regions. Source localization delineated theta activity increase in frontal midline region, alpha decrease in superior parietal region, and beta increase in superior temporal gyrus with increase in memory load. In conclusion, FD as a nonlinear measure may serve as a sensitive index for quantifying dynamical changes in EEG signals during AVSTM tasks.

  12. Age-related effects on verbal and visuospatial memory are mediated by theta and alpha II rhythms.

    PubMed

    Reichert, Johanna Louise; Kober, Silvia Erika; Witte, Matthias; Neuper, Christa; Wood, Guilherme

    2016-01-01

    Both electrical brain activity during rest and memory functions change across the lifespan. Moreover, electrical brain activity is associated with memory functions. However, the interplay between all these effects has been investigated only scarcely. The present study investigated the extent to which the power of resting-state electroencephalographic (EEG) frequencies mediates the impact of aging on verbal and visuospatial memory. Seventy healthy participants with 22 to 83years of age completed a visuospatial and verbal learning and memory test and provided eyes-open and eyes-closed resting-state EEG data. Robust age-related effects on behavioral and EEG data were observed. Mediation analyses showed that the relative power of the theta (4-8Hz) frequency band in fronto-central locations partly explained the negative age-related effect on delayed recall in the verbal memory task. The relative power of the alpha II (10-12Hz) frequency band in mainly parietal locations partly explained the negative impact of age on immediate and delayed recall in the visuospatial task. Results indicate that spontaneous brain activity carries specific information about aging processes and predicts the level of competence in verbal and visuospatial memory tasks.

  13. 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.

  14. Use of electroencephalography (EEG) to assess CNS changes produced by pesticides with different modes of action: effects of permethrin, deltamethrin, fipronil, imidacloprid, carbaryl, and triadimefon.

    PubMed

    Freeborn, Danielle L; McDaniel, Katherine L; Moser, Virginia C; Herr, David W

    2015-01-15

    The electroencephalogram (EEG) is an apical measure, capable of detecting changes in brain neuronal activity produced by internal or external stimuli. We assessed whether pesticides with different modes of action produced different changes in the EEG of adult male Long-Evans rats. The EEG was recorded using two montages (visual cortex referenced to the cerebellum and to the frontal cortex) in unrestrained rats at the time of peak behavioral effects. Pesticides included: permethrin and deltamethrin (Type I and Type II pyrethroids; 2 h), fipronil (single and repeated doses; phenylpyrazole; 6 h), imidacloprid (neonicotinoid; 2 h), carbaryl (carbamate; 0.5 h), and triadimefon (triazole; 1 h), using dosages that produced approximately an ED30 or an ED50-ED80 change in motor activity. Permethrin (43, 100 mg/kg) increased amplitudes or areas (delta, alpha, or gamma bands) in the EEG. Deltamethrin (2.5, 5.5 mg/kg) reduced the amplitudes or areas of the delta, theta, alpha, beta, and gamma bands, but the changes were not dose-related. A single treatment with fipronil (25, 50 mg/kg, but not 5, 10 mg/kg) decreased gamma band area. Additional changes in the delta, theta, and gamma bands were observed when fipronil (5, 10 mg/kg) was administered for 14 days. Imidacloprid (50, 100 mg/kg) did not alter the EEG. Carbaryl (10, 50 mg/kg) decreased theta area, and decreased delta and increased beta frequency. Triadimefon (75, 150 mg/kg) produced minimal changes in the EEG. The results show that the EEG is affected differently by approximately equipotent doses of pesticides with different modes of action.

  15. The frequency of hippocampal theta rhythm is modulated on a circadian period and is entrained by food availability

    PubMed Central

    Munn, Robert G. K.; Tyree, Susan M.; McNaughton, Neil; Bilkey, David K.

    2015-01-01

    The hippocampal formation plays a critical role in the generation of episodic memory. While the encoding of the spatial and contextual components of memory have been extensively studied, how the hippocampus encodes temporal information, especially at long time intervals, is less well understood. The activity of place cells in hippocampus has previously been shown to be modulated at a circadian time-scale, entrained by a behavioral stimulus, but not entrained by light. The experimental procedures used in the previous study of this phenomenon, however, necessarily conflated two alternative entraining stimuli, the exposure to the recording environment and the availability of food, making it impossible to distinguish between these possibilities. Here we demonstrate that the frequency of theta-band hippocampal EEG varies with a circadian period in freely moving animals and that this periodicity mirrors changes in the firing rate of hippocampal neurons. Theta activity serves, therefore, as a proxy of circadian-modulated hippocampal neuronal activity. We then demonstrate that the frequency of hippocampal theta driven by stimulation of the reticular formation also varies with a circadian period. Because this effect can be observed without having to feed the animal to encourage movement we were able to identify what stimulus entrains the circadian oscillation. We show that with reticular-activated recordings started at various times of the day the frequency of theta varies quasi-sinusoidally with a 25 h period and phase-aligned when referenced to the animal’s regular feeding time, but not the recording start time. Furthermore, we show that theta frequency consistently varied with a circadian period when the data obtained from repeated recordings started at various times of the day were referenced to the start of food availability in the recording chamber. This pattern did not occur when data were referenced to the start of the recording session or to the actual time of

  16. Influence of age on the interrelation between EEG frequency bands during NREM and REM sleep.

    PubMed

    Mann, Klaus; Röschke, Joachim

    2004-04-01

    The age-dependence of temporal interrelations between distinct frequency bands of sleep EEG was investigated in a group of 59 healthy young and middle-aged males via cross correlation analysis. Based on global evaluation throughout the entire night, a highly significant decline of the delta/theta correlation with increasing age was found. A separate analysis for non-rapid eye movement (NREM) and rapid eye movement (REM) sleep revealed different changes with aging. During NREM sleep, the correlation between the delta and theta frequency bands decreased with increasing age. In contrast, during REM sleep, a stronger correlation became obvious between the theta, alpha, and beta frequency bands with increasing age, whereas the lower frequency components were not affected. These findings indicate that aging processes seem to interact with sleep EEG rhythms in a complex manner, where most conspicuous is a disintegration of the activities in the lower frequency range, both concerning the successive sleep cycles across the night and the micro-structure of NREM sleep.

  17. Brain vascular damage of cholinergic pathways and EEG markers in mild cognitive impairment.

    PubMed

    Moretti, Davide Vito; Pievani, Michela; Fracassi, Claudia; Geroldi, Cristina; Calabria, Marco; De Carli, Charles S; Rossini, Paolo Maria; Frisoni, Giovanni Battista

    2008-11-01

    We evaluated changes of brain rhythmicity correlating with the cerebrovascular damage of long-range (capsular tract) and short-range (medial and perisylvian tracts) cholinergic pathways in subjects with mild cognitive impairment (MCI). Ninety-four MCI subjects underwent electroencephalographic (EEG) recordings and magnetic resonance imaging (MRI). The EEG relative power spectrum was computed in delta, theta, alpha1, alpha2, alpha3, beta1, beta2, gamma frequency bands. White matter hyperintensities along each cholinergic tract was segmented on MRI. Three MCI subgroups were identified based on increasing damage. A significant increase of delta and theta power band was found in patients with the highest total cholinergic burden as well as in patients with highest capsular pathway damage; total load of cholinergic damage was also associated with decreased gamma power band. Alpha frequency was differentially affected: decrease of alpha3 power band was associated with the greatest damage of the capsular pathway whereas increase of alpha3 power band was associated with the greatest damage of the perisylvian pathway. Multiple regression linear analysis showed independent association of cholinergic damage with delta, theta and gamma frequency, not with alpha frequency. In conclusion, the damage of long-range and short range cholinergic tracts has possible different implications for cognitive functions in MCI subjects.

  18. Spectral and brain mapping analysis of EEG based on Pwelch in schizophrenic patients

    NASA Astrophysics Data System (ADS)

    Akbar, Y.; Khotimah, S. N.; Haryanto, F.

    2016-03-01

    The aim of this study is to investigate and analyze the differences of power spectral distribution in various frequency bands between healthy subjects and schizophrenic patients. Subjects in this study were 8 people consisting of 4 schizophrenic patients and 4 healthy subjects. Subjects were recorded from 12 electrodes with Electroencephalography (EEG). EEG signals were recorded during a resting eye-closed state for 4-6 minutes. Data were extracted and analyzed by centering and filtering, then performed using Welch Periodogram technique for the spectral estimation with a Hamming window. The results of this study showed that delta power spectral in schizophrenic patients increased ten times from healthy subjects; theta power spectral in schizophrenic patients increased three times from healthy subjects; alpha power spectral in schizophrenic patients decreased with an increase of one third of healthy subjects. These results were confirmed by Kolmogorov-Smirnov test showing there were significant differences between schizophrenic and healthy subjects on delta, theta and alpha brain wave. Based on the results of Brain Mapping analysis showed that there was significant increasing in the activity of delta waves and theta waves in frontal lobe of schizophrenics, whereas the alpha waves indicated a decrease in the occipital lobe in all schizophrenic patients.

  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. Diagnosis of Alzheimer's disease from EEG by means of synchrony measures in optimized frequency bands.

    PubMed

    Gallego-Jutglà, Esteve; Elgendi, Mohamed; Vialatte, Francois; Solé-Casals, Jordi; Cichocki, Andrzej; Latchoumane, Charles; Jeong, Jaesung; Dauwels, Justin

    2012-01-01

    Several clinical studies have reported that EEG synchrony is affected by Alzheimer's disease (AD). In this paper a frequency band analysis of AD EEG signals is presented, with the aim of improving the diagnosis of AD using EEG signals. In this paper, multiple synchrony measures are assessed through statistical tests (Mann-Whitney U test), including correlation, phase synchrony and Granger causality measures. Moreover, linear discriminant analysis (LDA) is conducted with those synchrony measures as features. For the data set at hand, the frequency range (5-6 Hz) yields the best accuracy for diagnosing AD, which lies within the classical theta band (4-8 Hz). The corresponding classification error is 4.88% for directed transfer function (DTF) Granger causality measure. Interestingly, results show that EEG of AD patients is more synchronous than in healthy subjects within the optimized range 5-6 Hz, which is in sharp contrast with the loss of synchrony in AD EEG reported in many earlier studies. This new finding may provide new insights about the neurophysiology of AD. Additional testing on larger AD datasets is required to verify the effectiveness of the proposed approach.

  1. Effect of total sleep deprivation on reaction time and waking EEG activity in man.

    PubMed

    Lorenzo, I; Ramos, J; Arce, C; Guevara, M A; Corsi-Cabrera, M

    1995-06-01

    Nine paid volunteers were sleep deprived over a period of 40 hours. Every 2 hours during total sleep deprivation (TSD) and after recovery sleep, oral temperature (OT), reaction time (RT) in a vigilance task and electroencephalogram (EEG) with eyes open and closed (C3, C4, T3 and T4) were recorded. Ten artifact-free samples from each condition were Fourier transformed. Absolute power was calculated for six bands. Analyses of variance with deprivation and time of day as factors showed the following significant results: 1) TSD induced an increase in RT, of theta power in all derivations, of beta power in both centrals and a decrease of alpha power with eyes closed; OT was not affected. 2) All bands showed a peak of power at 1800 hours, 2 hours in advance of the OT acrophase at 2000 hours. All variables recovered baseline values after 1 night of sleep. Significant linear correlations of hours of wakefulness with EEG and RT, and of EEG power with OT and RT, were observed. The present findings show a linear increase in EEG power and RT with TSD, and a diurnal oscillation of EEG power, which is independent of TSD.

  2. Cannabinoid antagonist SLV326 induces convulsive seizures and changes in the interictal EEG in rats.

    PubMed

    Perescis, Martin F J; de Bruin, Natasja; Heijink, Liesbeth; Kruse, Chris; Vinogradova, Lyudmila; Lüttjohann, Annika; van Luijtelaar, Gilles; van Rijn, Clementina M

    2017-01-01

    Cannabinoid CB1 antagonists have been investigated for possible treatment of e.g. obesity-related disorders. However, clinical application was halted due to their symptoms of anxiety and depression. In addition to these adverse effects, we have shown earlier that chronic treatment with the CB1 antagonist rimonabant may induce EEG-confirmed convulsive seizures. In a regulatory repeat-dose toxicity study violent episodes of "muscle spasms" were observed in Wistar rats, daily dosed with the CB1 receptor antagonist SLV326 during 5 months. The aim of the present follow-up study was to investigate whether these violent movements were of an epileptic origin. In selected SLV326-treated and control animals, EEG and behavior were monitored for 24 hours. 25% of SLV326 treated animals showed 1 to 21 EEG-confirmed generalized convulsive seizures, whereas controls were seizure-free. The behavioral seizures were typical for a limbic origin. Moreover, interictal spikes were found in 38% of treated animals. The frequency spectrum of the interictal EEG of the treated rats showed a lower theta peak frequency, as well as lower gamma power compared to the controls. These frequency changes were state-dependent: they were only found during high locomotor activity. It is concluded that long term blockade of the endogenous cannabinoid system can provoke limbic seizures in otherwise healthy rats. Additionally, SLV326 alters the frequency spectrum of the EEG when rats are highly active, suggesting effects on complex behavior and cognition.

  3. Cannabinoid antagonist SLV326 induces convulsive seizures and changes in the interictal EEG in rats

    PubMed Central

    de Bruin, Natasja; Heijink, Liesbeth; Kruse, Chris; Vinogradova, Lyudmila; Lüttjohann, Annika; van Luijtelaar, Gilles; van Rijn, Clementina M.

    2017-01-01

    Cannabinoid CB1 antagonists have been investigated for possible treatment of e.g. obesity-related disorders. However, clinical application was halted due to their symptoms of anxiety and depression. In addition to these adverse effects, we have shown earlier that chronic treatment with the CB1 antagonist rimonabant may induce EEG-confirmed convulsive seizures. In a regulatory repeat-dose toxicity study violent episodes of “muscle spasms” were observed in Wistar rats, daily dosed with the CB1 receptor antagonist SLV326 during 5 months. The aim of the present follow-up study was to investigate whether these violent movements were of an epileptic origin. In selected SLV326-treated and control animals, EEG and behavior were monitored for 24 hours. 25% of SLV326 treated animals showed 1 to 21 EEG-confirmed generalized convulsive seizures, whereas controls were seizure-free. The behavioral seizures were typical for a limbic origin. Moreover, interictal spikes were found in 38% of treated animals. The frequency spectrum of the interictal EEG of the treated rats showed a lower theta peak frequency, as well as lower gamma power compared to the controls. These frequency changes were state-dependent: they were only found during high locomotor activity. It is concluded that long term blockade of the endogenous cannabinoid system can provoke limbic seizures in otherwise healthy rats. Additionally, SLV326 alters the frequency spectrum of the EEG when rats are highly active, suggesting effects on complex behavior and cognition. PMID:28151935

  4. Theta Pinch Coil Design for SSX

    NASA Astrophysics Data System (ADS)

    Shrock, J. E.; Han, J.; Kaur, M.; Brown, M. R.; Schaffner, D. A.

    2016-10-01

    We present the essential physics and design parameters behind a theta pinch coil used on SSX. The coil is used as an accelerator to drive flux behind a Taylor plume traveling about 30 km/sec. Operating between 25 and 40 kV on a time scale < 10 μs , the design focuses on minimizing the quarter cycle rise time (π/2√{ LC }) of the coil while maintaining the necessary precautions for working at high voltage. Our design works with 1.1 and 3.3 μF capacitors and a maximum stored electrical energy of U =1/2 CV2 = 880 J (at the lower capacitance). This electrical energy is converted into kinetic energy in the plume. Each plume has a mass greater than 30 μg , giving an initial kinetic energy of at least 14 J . At perfect efficiency, the upper bound of the plume velocity will be 240 km/sec using the lower capacitance circuit. Work supported by DOE OFES and ARPA-E ALPHA programs.

  5. Blinded, multi-center validation of EEG and rating scales in identifying ADHD within a clinical sample.

    PubMed

    Snyder, Steven M; Quintana, Humberto; Sexson, Sandra B; Knott, Peter; Haque, A F M; Reynolds, Donald A

    2008-06-30

    Previous validation studies of attention deficit/hyperactivity disorder (ADHD) assessment by rating scales or EEG have provided Class-IV evidence per standards of the American Academy of Neurology. To investigate clinical applications, we collected Class-I evidence, namely from a blinded, prospective, multi-center study of a representative clinical sample categorized with a clinical standard. Participating males (101) and females (58) aged 6 to 18 had presented to one of four psychiatric and pediatric clinics because of the suspected presence of attention and behavior problems. DSM-IV diagnosis was performed by clinicians assisted with a semi-structured clinical interview. EEG (theta/beta ratio) and ratings scales (Conners Rating Scales-Revised and ADHD Rating Scales-IV) were collected separately in a blinded protocol. ADHD prevalence in the clinical sample was 61%, whereas the remainder had other childhood/adolescent disorders or no diagnosis. Comorbidities were observed in 66% of ADHD patients and included mood, anxiety, disruptive, and learning disorders at rates similar to previous findings. EEG identified ADHD with 87% sensitivity and 94% specificity. Rating scales provided sensitivity of 38-79% and specificity of 13-61%. While parent or teacher identification of ADHD by rating scales was reduced in accuracy when applied to a diverse clinical sample, theta/beta ratio changes remained consistent with the clinician's ADHD diagnosis. Because theta/beta ratio changes do not identify comorbidities or alternative diagnoses, the results do not support the use of EEG as a stand-alone diagnostic and should be limited to the interpretation that EEG may complement a clinical evaluation for ADHD.

  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. EEG oscillations during sleep and dream recall: state- or trait-like individual differences?

    PubMed Central

    Scarpelli, Serena; D’Atri, Aurora; Gorgoni, Maurizio; Ferrara, Michele; De Gennaro, Luigi

    2015-01-01

    Dreaming represents a peculiar form of cognitive activity during sleep. On the basis of the well-known relationship between sleep and memory, there has been a growing interest in the predictive role of human brain activity during sleep on dream recall. Neuroimaging studies indicate that rapid eye movement (REM) sleep is characterized by limbic activation and prefrontal cortex deactivation. This pattern could explain the presence of emotional contents in dream reports. Furthermore, the morphoanatomical measures of amygdala and hippocampus predict some features of dream contents (bizarreness, vividness, and emotional load). More relevant for a general view of dreaming mechanisms, empirical data from neuropsychological and electroencephalographic (EEG) studies support the hypothesis that there is a sort of continuity between the neurophysiological mechanisms of encoding and retrieval of episodic memories across sleep and wakefulness. A notable overlap between the electrophysiological mechanisms underlying emotional memory formation and some peculiar EEG features of REM sleep has been suggested. In particular, theta (5–8 Hz) EEG oscillations on frontal regions in the pre-awakening sleep are predictive of dream recall, which parallels the predictive relation during wakefulness between theta activity and successful retrieval of episodic memory. Although some observations support an interpretation more in terms of an intraindividual than interindividual mechanism, the existing empirical evidence still precludes from definitely disentangling if this relation is explained by state- or trait-like differences. PMID:25999908

  8. Developmental alterations in noxious-evoked EEG activity recorded from rat primary somatosensory cortex.

    PubMed

    Devonshire, I M; Greenspon, C M; Hathway, G J

    2015-10-01

    Primary somatosensory cortex (S1) contains a nociceptive map that localizes potential tissue damage on the body and encodes stimulus intensity. An objective and specific biomarker of pain however is currently lacking and is urgently required for use in non-verbal clinical populations as well as in the validation of pre-clinical pain models. Here we describe studies to see if the responses of the S1 in juvenile rats are different to those in the adult. We recorded electroencephalogram (EEG) responses from S1 of lightly-anesthetized Sprague-Dawley rats at either postnatal day 21 or postnatal day 40 during the presentation of noxious (55 °C) or innocuous (30 °C) thermal stimuli applied to the plantar surface of the left hindpaw. The total EEG power across the recording period was the same in both ages after stimulation but the frequency distribution was significantly affected by age. Noxious heat evoked a significant increase in theta band (4-8 Hz) activity in adults only (P<0.0001 compared to baseline; P<0.0001 compared to juveniles). There were no significant differences in EEG responses to innocuous thermal stimuli. These data show that there are significant alterations in the processing of nociceptive inputs within the maturing cortex and that cortical theta activity is involved only in the adult cortical response to noxious stimulation.

  9. EEG oscillations during sleep and dream recall: state- or trait-like individual differences?

    PubMed

    Scarpelli, Serena; D'Atri, Aurora; Gorgoni, Maurizio; Ferrara, Michele; De Gennaro, Luigi

    2015-01-01

    Dreaming represents a peculiar form of cognitive activity during sleep. On the basis of the well-known relationship between sleep and memory, there has been a growing interest in the predictive role of human brain activity during sleep on dream recall. Neuroimaging studies indicate that rapid eye movement (REM) sleep is characterized by limbic activation and prefrontal cortex deactivation. This pattern could explain the presence of emotional contents in dream reports. Furthermore, the morphoanatomical measures of amygdala and hippocampus predict some features of dream contents (bizarreness, vividness, and emotional load). More relevant for a general view of dreaming mechanisms, empirical data from neuropsychological and electroencephalographic (EEG) studies support the hypothesis that there is a sort of continuity between the neurophysiological mechanisms of encoding and retrieval of episodic memories across sleep and wakefulness. A notable overlap between the electrophysiological mechanisms underlying emotional memory formation and some peculiar EEG features of REM sleep has been suggested. In particular, theta (5-8 Hz) EEG oscillations on frontal regions in the pre-awakening sleep are predictive of dream recall, which parallels the predictive relation during wakefulness between theta activity and successful retrieval of episodic memory. Although some observations support an interpretation more in terms of an intraindividual than interindividual mechanism, the existing empirical evidence still precludes from definitely disentangling if this relation is explained by state- or trait-like differences.

  10. 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.

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

    PubMed

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

    2011-03-01

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

  12. EEG during masturbation and ejaculation.

    PubMed

    Graber, B; Rohrbaugh, J W; Newlin, D B; Varner, J L; Ellingson, R J

    1985-12-01

    The occurrence of a distinctive EEG pattern specifically related to sexual arousal and orgasm would provide a reliable and convenient means of identifying such events in the laboratory and would also provide clues to cerebral structures involved in the processes. EEG-polygraph recordings were obtained under rigorously controlled conditions in four normal male subjects during masturbation and ejaculation. The EEG data were subjected to both impressionistic and quantitative analyses. They showed no remarkable changes during the sequence of relevant physiological responses. The sole effect was a slight depression of alpha activity, a well-known nonspecific effect associated with changes in attention and arousal. Examination of the literature shows little agreement among reported results of studies of EEG changes during orgasm. It is likely that at least some reported changes were artifactual. It is concluded that the case for the existence of EEG changes specifically related to sexual arousal and orgasm remains unproven.

  13. An EEG-based machine learning method to screen alcohol use disorder.

    PubMed

    Mumtaz, Wajid; Vuong, Pham Lam; Xia, Likun; Malik, Aamir Saeed; Rashid, Rusdi Bin Abd

    2017-04-01

    Screening alcohol use disorder (AUD) patients has been challenging due to the subjectivity involved in the process. Hence, robust and objective methods are needed to automate the screening of AUD patients. In this paper, a machine learning method is proposed that utilized resting-state electroencephalography (EEG)-derived features as input data to classify the AUD patients and healthy controls and to perform automatic screening of AUD patients. In this context, the EEG data were recorded during 5 min of eyes closed and 5 min of eyes open conditions. For this purpose, 30 AUD patients and 15 aged-matched healthy controls were recruited. After preprocessing the EEG data, EEG features such as inter-hemispheric coherences and spectral power for EEG delta, theta, alpha, beta and gamma bands were computed involving 19 scalp locations. The selection of most discriminant features was performed with a rank-based feature selection method assigning a weight value to each feature according to a criterion, i.e., receiver operating characteristics curve. For example, a feature with large weight was considered more relevant to the target labels than a feature with less weight. Therefore, a reduced set of most discriminant features was identified and further be utilized during classification of AUD patients and healthy controls. As results, the inter-hemispheric coherences between the brain regions were found significantly different between the study groups and provided high classification efficiency (Accuracy = 80.8, sensitivity = 82.5, and specificity = 80, F-Measure = 0.78). In addition, the power computed in different EEG bands were found significant and provided an overall classification efficiency as (Accuracy = 86.6, sensitivity = 95, specificity = 82.5, and F-Measure = 0.88). Further, the integration of these EEG feature resulted into even higher results (Accuracy = 89.3 %, sensitivity = 88.5 %, specificity = 91 %, and F-Measure = 0.90). Based

  14. Sodium valproate interactions with the HPNS: EEG and behavioral observations.

    PubMed

    Pearce, P C; Clarke, D; Doré, C J; Halsey, M J; Luff, N P; Maclean, C J

    1989-03-01

    A new baboon model was used to investigate the therapuetic effect of sodium valproate on the high pressure neurologic syndrome (HPNS). A hyperbaric chamber was used to achieve environmental pressures of 61 ATA, over a 5-h period. Eight animals underwent two compressions, a control and a valproate-treated compression (half the animals had valproate on the first compression). Mild signs of HPNS (e.g., paw and limb tremor) were first observed at approximately 20 ATA. More severe signs (e.g., whole body tremor, myoclonus, and vomiting) were observed above 40 ATA. Sodium valproate was administered during the compression phase and for 2 wk previously. It was effective at the higher pressures above 41 ATA in reducing the severity of the signs of HPNS. The major effect of pressure on the EEG was to increase alpha and theta wave amplitude in a linear manner. Alpha wave amplitude was reduced by sodium valproate.

  15. Theta synchronization and alpha desynchronization in a memory task.

    PubMed

    Klimesch, W; Doppelmayr, M; Schimke, H; Ripper, B

    1997-03-01

    In the present study, we examined the hypothesis that episodic encoding and retrieval processes are primarily reflected by a task-related increase in theta power. Individuals performed a recognition task with a total of 192 words. The electroencephalogram was recorded during the study and recognition phase. The results show that only those words that were later correctly recognized produced a significant increase in theta power during encoding. During the actual recognition processes too, a significant theta synchronization (increase in band power) was found for correctly remembered words only. In contrast to the theta band, remembered and not remembered words revealed a complex pattern of desynchronization in the lower and upper alpha band that was different during encoding and recognition.

  16. Reversed theta sequences of hippocampal cell assemblies during backward travel.

    PubMed

    Cei, Anne; Girardeau, Gabrielle; Drieu, Céline; Kanbi, Karim El; Zugaro, Michaël

    2014-05-01

    Hippocampal cell assemblies coding for past, present and future events form theta-timescale (~100 ms) sequences that represent spatio-temporal episodes. However, the underlying mechanisms remain largely unknown. We recorded hippocampal and entorhinal cortical activity as rats experienced backward travel on a model train. Although the firing fields of place cells remained stable, the order in which they were activated in the theta sequence was reversed during backward travel. Thus, hippocampal cell assemblies coordinated their relative timing to correctly predict the sequential traversal of place fields in reverse order. At the single-cell level, theta phase represented distance traveled through the field, even though the head of the rat was oriented opposite to travel direction and entorhinal head-direction cells maintained their preferred firing direction. Our results challenge most theoretical models of theta sequence generation in the hippocampus.

  17. 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.

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

    PubMed

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

    2016-08-01

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

  19. [EEG changes during sedation with gamma-hydroxybutyric acid].

    PubMed

    Entholzner, E; Mielke, L; Pichlmeier, R; Weber, F; Schneck, H

    1995-05-01

    min) had been recorded. Patients receiving long-term sedation were studied daily for an additional 15-min period. Corresponding well to the clinical findings, EEG pattern changed to a slow delta-theta or delta-only rhythm within 10 min of the start of injection. Alpha and beta power decreased, while delta activity exhibited an increase. All changes were most obvious in frontal and central areas of the brain. In about one out of three patients, a burst--suppression pattern developed. Since automatic processing of EEG may fail to detect special patterns like the looked-for 3/s spikes and waves, the raw EEG was analysed visually by an expert neurologist. Both processed and conventionally analysed EEG were free of any seizure-like electrical activity. CONCLUSION. We conclude that animal data may not apply to the use of GHB in humans, provided the dose is limited to the clinical needs. GHB is used in clinical practice in doses twice as high, or even higher, than the one we use for induction, without obvious side effects. However, the suppression of theta rhythm we observed in about half of the patients studied may indicate that even less than 50 mg/kg BW might be sufficient for adequate sedation.

  20. A computational study on plasticity during theta cycles at Schaffer collateral synapses on CA1 pyramidal cells in the hippocampus.

    PubMed

    Saudargiene, Ausra; Cobb, Stuart; Graham, Bruce P

    2015-02-01

    Cellular activity in the CA1 area of the hippocampus waxes and wanes at theta frequency (4-8 Hz) during exploratory behavior of rats. Perisomatic inhibition onto pyramidal cells tends to be strongest out of phase with pyramidal cell activity, whereas dendritic inhibition is strongest in phase with pyramidal cell activity. Synaptic plasticity also varies across the theta cycle, from strong long-term potentiation (LTP) to long-term depression (LTD), putatively corresponding to encoding and retrieval phases for information patterns encoded by pyramidal cell activity (Hasselmo et al. (2002a) Neural Comput 14:793-817). The mechanisms underpinning the phasic changes in plasticity are not clear, but it is likely that inhibition plays a role by affecting levels of electrical activity and calcium concentration at synapses. We explore the properties of synaptic plasticity during theta at Schaffer collateral synapses on CA1 pyramidal neurons and the influence of spatially and temporally targeted inhibition using a detailed multicompartmental model of the CA1 pyramidal neuron microcircuit and a phenomenological model of synaptic plasticity. The results suggest CA3-CA1 synapses are potentiated on one phase of theta due to high calcium levels provided by paired weak CA3 and layer III entorhinal cortex (EC) inputs even when somatic spiking is inhibited by perisomatic interneuron activity. Weak CA3 inputs alone induce lower calcium transients and result in depression of the CA3-CA1 synapses. These synapses are depressed if activated in phase with dendritic inhibition as strong CA3 inputs alone are not able to cause high calcium in this theta phase even though the CA1 pyramidal neuron shows somatic spiking. Dendritic inhibition acts as a switch that prevents LTP and promotes LTD during the retrieval phases of the theta rhythm in CA1 pyramidal cell. This may be important for not overly reinforcing recalled memories and in forgetting no longer relevant memories.

  1. Dry EEG Electrodes

    PubMed Central

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

    2014-01-01

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

  2. Interpreting EEG alpha activity.

    PubMed

    Bazanova, O M; Vernon, D

    2014-07-01

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

  3. Reduced mind wandering in experienced meditators and associated EEG correlates.

    PubMed

    Brandmeyer, Tracy; Delorme, Arnaud

    2016-11-04

    One outstanding question in the contemplative science literature relates to the direct impact of meditation experience on the monitoring of internal states and its respective correspondence with neural activity. In particular, to what extent does meditation influence the awareness, duration and frequency of the tendency of the mind to wander. To assess the relation between mind wandering and meditation, we tested 2 groups of meditators, one with a moderate level of experience (non-expert) and those who are well advanced in their practice (expert). We designed a novel paradigm using self-reports of internal mental states based on an experiential sampling probe paradigm presented during ~1 h of seated concentration meditation to gain insight into the dynamic measures of electroencephalography (EEG) during absorption in meditation as compared to reported mind wandering episodes. Our results show that expert meditation practitioners report a greater depth and frequency of sustained meditation, whereas non-expert practitioners report a greater depth and frequency of mind wandering episodes. This is one of the first direct behavioral indices of meditation expertise and its associated impact on the reduced frequency of mind wandering, with corresponding EEG activations showing increased frontal midline theta and somatosensory alpha rhythms during meditation as compared to mind wandering in expert practitioners. Frontal midline theta and somatosensory alpha rhythms are often observed during executive functioning, cognitive control and the active monitoring of sensory information. Our study thus provides additional new evidence to support the hypothesis that the maintenance of both internal and external orientations of attention may be maintained by similar neural mechanisms and that these mechanisms may be modulated by meditation training.

  4. Analytical Insights on Theta-Gamma Coupled Neural Oscillators

    PubMed Central

    2013-01-01

    In this paper, we study the dynamics of a quadratic integrate-and-fire neuron, spiking in the gamma (30–100 Hz) range, coupled to a delta/theta frequency (1–8 Hz) neural oscillator. Using analytical and semianalytical methods, we were able to derive characteristic spiking times for the system in two distinct regimes (depending on parameter values): one regime where the gamma neuron is intrinsically oscillating in the absence of theta input, and a second one in which gamma spiking is directly gated by theta input, i.e., windows of gamma activity alternate with silence periods depending on the underlying theta phase. In the former case, we transform the equations such that the system becomes analogous to the Mathieu differential equation. By solving this equation, we can compute numerically the time to the first gamma spike, and then use singular perturbation theory to find successive spike times. On the other hand, in the excitable condition, we make direct use of singular perturbation theory to obtain an approximation of the time to first gamma spike, and then extend the result to calculate ensuing gamma spikes in a recursive fashion. We thereby give explicit formulas for the onset and offset of gamma spike burst during a theta cycle, and provide an estimation of the total number of spikes per theta cycle both for excitable and oscillator regimes. PMID:23945442

  5. Frontal theta activity during working memory in test anxiety.

    PubMed

    Shi, Zhan; Gao, Xin; Zhou, Renlai

    2015-03-04

    Previous studies have shown that working memory (WM) processes are related to frontal-midline theta (FM-theta) activity (4-8 Hz) and test anxiety impairs WM performance. However, the effect of test anxiety on FM-theta activity during WM has not been investigated as yet. To examine this question, 37 undergraduates were asked to complete a modified reading span task involving neutral working memory capacity (WMC) and emotional WMC while their electroencephalography was measured. The results showed that relative to neutral WMC performance (the ability to remember the letter lists in the context of valence-neutral sentences), emotional WMC performance (the ability to remember the letter lists in the context of test-related sentences) was poorer for highly test anxious participants compared with lowly test anxious participants. Relative to FM-theta activity during remembering the letter lists in the valence-neutral context, FM-theta activity was weaker during remembering the letter lists in the test-related context for highly test anxious participants compared with lowly test anxious participants. These findings indicate that FM-theta is an index not only for successful WM manipulation but also for efficient prefrontal cortex functioning during WM.

  6. Flexible theta sequence compression mediated via phase precessing interneurons

    PubMed Central

    Chadwick, Angus; van Rossum, Mark CW; Nolan, Matthew F

    2016-01-01

    Encoding of behavioral episodes as spike sequences during hippocampal theta oscillations provides a neural substrate for computations on events extended across time and space. However, the mechanisms underlying the numerous and diverse experimentally observed properties of theta sequences remain poorly understood. Here we account for theta sequences using a novel model constrained by the septo-hippocampal circuitry. We show that when spontaneously active interneurons integrate spatial signals and theta frequency pacemaker inputs, they generate phase precessing action potentials that can coordinate theta sequences in place cell populations. We reveal novel constraints on sequence generation, predict cellular properties and neural dynamics that characterize sequence compression, identify circuit organization principles for high capacity sequential representation, and show that theta sequences can be used as substrates for association of conditioned stimuli with recent and upcoming events. Our results suggest mechanisms for flexible sequence compression that are suited to associative learning across an animal’s lifespan. DOI: http://dx.doi.org/10.7554/eLife.20349.001 PMID:27929374

  7. Functional brain networks in healthy subjects under acupuncture stimulation: An EEG study based on nonlinear synchronization likelihood analysis

    NASA Astrophysics Data System (ADS)

    Yu, Haitao; Liu, Jing; Cai, Lihui; Wang, Jiang; Cao, Yibin; Hao, Chongqing

    2017-02-01

    Electroencephalogram (EEG) signal evoked by acupuncture stimulation at "Zusanli" acupoint is analyzed to investigate the modulatory effect of manual acupuncture on the functional brain activity. Power spectral density of EEG signal is first calculated based on the autoregressive Burg method. It is shown that the EEG power is significantly increased during and after acupuncture in delta and theta bands, but decreased in alpha band. Furthermore, synchronization likelihood is used to estimate the nonlinear correlation between each pairwise EEG signals. By applying a threshold to resulting synchronization matrices, functional networks for each band are reconstructed and further quantitatively analyzed to study the impact of acupuncture on network structure. Graph theoretical analysis demonstrates that the functional connectivity of the brain undergoes obvious change under different conditions: pre-acupuncture, acupuncture, and post-acupuncture. The minimum path length is largely decreased and the clustering coefficient keeps increasing during and after acupuncture in delta and theta bands. It is indicated that acupuncture can significantly modulate the functional activity of the brain, and facilitate the information transmission within different brain areas. The obtained results may facilitate our understanding of the long-lasting effect of acupuncture on the brain function.

  8. Immediate effects of Alpha/theta and Sensory-Motor Rhythm feedback on music performance.

    PubMed

    Gruzelier, J H; Hirst, L; Holmes, P; Leach, J

    2014-07-01

    This is one of a series of investigations comparing two EEG-neurofeedback protocols - Alpha/theta (A/T) and Sensory-Motor Rhythm (SMR) - for performance enhancement in the Arts, here with the focus on music. The original report (Egner and Gruzelier, 2003) established a beneficial outcome for elite conservatoire musicians following A/T training in two investigations. Subsequently this A/T advantage was replicated for both advanced instrumental and novice singing abilities, including improvisation, while SMR training benefited novice performance only (Gruzelier, Holmes et al., 2014). Here we report a replication of the latter study in university instrumentalists who as before were novice singers with one design change - post-training performances were conducted within the tenth final session instead of on a subsequent occasion. As before expert judges rated the domains of Creativity/Musicality, Communication/Presentation and Technique. The proximity to training of the music performances within the last session likely compromised gains from A/T learning, but perhaps reinforced the impact of SMR training efficacy. In support of validation there was evidence of strong within- and across-session A/T learning and positive linear trends for across-session SMR/theta and SMR/beta-2 ratio learning. In support of mediation learning correlated with music performance. The A/T outcome was markedly discrepant from previous studies and should dispel any impression that the hypnogogic state itself is transferred to the performance context. The effects of SMR ratio training are consistent with an impact on lower-order abilities required in novice performance such as sustained attention and memory, and benefiting all three domains of music assessment.

  9. Theta phase synchrony and conscious target perception: impact of intensive mental training.

    PubMed

    Slagter, Heleen A; Lutz, Antoine; Greischar, Lawrence L; Nieuwenhuis, Sander; Davidson, Richard J

    2009-08-01

    The information processing capacity of the human mind is limited, as is evidenced by the attentional blink-a deficit in identifying the second of two targets (T1 and T2) presented in close succession. This deficit is thought to result from an overinvestment of limited resources in T1 processing. We previously reported that intensive mental training in a style of meditation aimed at reducing elaborate object processing, reduced brain resource allocation to T1, and improved T2 accuracy [Slagter, H. A., Lutz, A., Greischar, L. L., Francis, A. D., Nieuwenhuis, S., Davis, J., et al. Mental training affects distribution of limited brain resources. PloS Biology, 5, e138, 2007]. Here we report EEG spectral analyses to examine the possibility that this reduction in elaborate T1 processing rendered the system more available to process new target information, as indexed by T2-locked phase variability. Intensive mental training was associated with decreased cross-trial variability in the phase of oscillatory theta activity after successfully detected T2s, in particular, for those individuals who showed the greatest reduction in brain resource allocation to T1. These data implicate theta phase locking in conscious target perception, and suggest that after mental training the cognitive system is more rapidly available to process new target information. Mental training was not associated with changes in the amplitude of T2-induced responses or oscillatory activity before task onset. In combination, these findings illustrate the usefulness of systematic mental training in the study of the human mind by revealing the neural mechanisms that enable the brain to successfully represent target information.

  10. EEG Recording and Analysis for Sleep Research

    PubMed Central

    Campbell, Ian G.

    2010-01-01

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

  11. Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

    PubMed Central

    Baier-Bitterlich, G; Uberall, F; Bauer, B; Fresser, F; Wachter, H; Grunicke, H; Utermann, G; Altman, A; Baier, G

    1996-01-01

    T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation

  12. Melatonin versus chloral hydrate for recording sleep EEG.

    PubMed

    Ashrafi, Mahmoud Reza; Mohammadi, Mahmoud; Tafarroji, Javad; Shabanian, Reza; Salamati, Peyman; Zamani, Gholam Reza

    2010-05-01

    Although behavioral training could be successful in promoting electroencephalogram (EEG) compliance without restraint or sedation, sleep EEG may increase the yield of seizure activity. Furthermore uncooperative children not amenable to behavioral training require sedation for EEG recording. Our aim was to assess the impact of melatonin on the sleep EEG recording in comparison with chloral hydrate. Three hundred and forty eight patients (aged 1 month to 6 years) that were uncooperative with the EEG setup or referred for sleep EEG were enrolled in the study. Patients, partially sleep-deprived the night before, were randomly divided in two groups of melatonin and chloral hydrate on an alternative day basis, 174 patients in each group. Sleep onset latency in the chloral hydrate and melatonin groups was similar (Mann-Whitney test, P=0.113). However, sleep duration and drowsiness time were significantly shorter in the group of melatonin compared to the group of chloral hydrate (Mann-Whitney test, P<0.0001 and P<0.0001 respectively). More patients in the melatonin group (20 versus six patients in the chloral hydrate group) required a second dose of sedative for sleep induction (chi square test, P value=0.004). Seizure activities appeared in the electroencephalograms of 53% and 46% of patients in the melatonin and chloral hydrate groups respectively that were significantly higher in the melatonin group (chi square test, P=0.005). Few adverse effects occurred in both groups (Fisher's exact test, P=0.64). The shorter sleep duration and drowsiness period were the two advantages of melatonin over chloral hydrate. Furthermore higher yield of seizure activity detection in melatonin sedated patients was in favor of its prescription for sleep EEG recording in the pediatric population.

  13. Cross coherence independent component analysis in resting and action states EEG discrimination

    NASA Astrophysics Data System (ADS)

    Almurshedi, A.; Ismail, A. K.

    2014-11-01

    Cross Coherence time frequency transform and independent component analysis (ICA) method were used to analyse the electroencephalogram (EEG) signals in resting and action states during open and close eyes conditions. From the topographical scalp distributions of delta, theta, alpha, and beta power spectrum can clearly discriminate between the signal when the eyes were open or closed, but it was difficult to distinguish between resting and action states when the eyes were closed. In open eyes condition, the frontal area (Fp1, Fp2) was activated (higher power) in delta and theta bands whilst occipital (O1, O2) and partial (P3, P4, Pz) area of brain was activated alpha band in closed eyes condition. The cross coherence method of time frequency analysis is capable of discrimination between rest and action brain signals in closed eyes condition.

  14. Spectral characteristics and linear-nonlinear synchronization changes of different EEG frequency bands during the CNV.

    PubMed

    Molnár, Márk; Csuhaj, Roland; Gaál, Zsófia Anna; Czigler, Balázs; Ulbert, István; Boha, Roland; Kondákor, István

    2008-05-01

    During the CNV recorded in a simple auditory working memory task, task-specific decrease of the relative delta band and a transient increase of the absolute theta band were seen, accompanied by an increase of the absolute alpha1 and alpha2 bands in the posterior region. The decreased delta power probably corresponds to increased task-evoked arousal, whereas the transient theta power increase corresponds to working memory demand and possibly to the orienting response. The increased alpha1 and alpha2 power may be a manifestation of a top-down mechanism revealing control over the execution of a response. The area-specific, task-related, and frequency-dependent changes of EEG complexity measures indicate frontally increasing complexity during the early part of the CNV in the beta frequency bands, which underscores the importance of this region in the mechanisms of anticipatory behavior.

  15. Response conflict processes' classification in 7 and 9 year old children using EEG brain connectivity measures.

    PubMed

    Almabruk, T; Iyer, K; Girdler, S; Khan, M M; Tan, T

    2016-08-01

    Investigating cognitive development of children poses interesting challenges pertaining to emergence of children's' ability to think and understand. Psychological tasks that involve conflict, like the Flanker task, are widely used to understand development of response conflict processes. In this study, EEG signals were used to examine the coherence and imaginary part of coherency within the delta, theta, alpha and beta bands across different conditions of the Flanker task. Longitudinal data were collected from a group of typically developing children at ages of seven and nine. We found that the imaginary part of coherency was more helpful in distinguishing between stimuli - alpha and beta bands resulted in 90.90% classification rate in seven year old children. The beta and theta bands were found to be more effective for stimuli classification in nine year old children - more than 84.09% classification accuracy was achieved.

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

    NASA Astrophysics Data System (ADS)

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

    1995-08-01

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

  17. EEG Biofeedback as a Treatment for Substance Use Disorders: Review, Rating of Efficacy, and Recommendations for Further Research

    PubMed Central

    Cannon, Rex L.; Trudeau, David L.

    2008-01-01

    Electroencephalographic (EEG) biofeedback has been employed in substance use disorder (SUD) over the last three decades. The SUD is a complex series of disorders with frequent comorbidities and EEG abnormalities of several types. EEG biofeedback has been employed in conjunction with other therapies and may be useful in enhancing certain outcomes of therapy. Based on published clinical studies and employing efficacy criteria adapted by the Association for Applied Psychophysiology and Biofeedback and the International Society for Neurofeedback and Research, alpha theta training—either alone for alcoholism or in combination with beta training for stimulant and mixed substance abuse and combined with residential treatment programs, is probably efficacious. Considerations of further research design taking these factors into account are discussed and descriptions of contemporary research are given. PMID:18214670

  18. 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.

  19. [Gender differences in EEG coherence changes during figural creative thinking: the efficacy coupling].

    PubMed

    Vol'f, N V; Tarasova, I V; Razumnikova, O M

    2009-01-01

    The study was aimed to explore the features of interaction between cortical areas during figural creative task performance in high- and low-creative men and women. We divided the participants into two groups with high and low creativity by the median of originality score. EEG was recorded at rest and during task performance (Torrance Tests of Creative Thinking "Incomplete figures"). The EEG coherence was computed in six frequency bands from theta1 to beta2. We analyzed the total values of coherence for each of 16 sites, calculated separately for intrahemispheric and interhemispheric connections. In the theta2, alphal, and alpha2 bands, coherence values decreased in task performance as compared to baseline in subjects with lower originality scores, whereas in subjects with higher scores, they increased in the theta2 and alpha1 bands. The decrease in the alpha2 band in the higher-creativity group was significantly lower in comparison with the decrease in the lower-score group. In the alpha2 band, the interaction of gender, creativity, laterality, and electrode position factors was also found during analysis of task-induced coherence changes. Further examination of the interaction showed the similarity of EEG coherence patterns in men and women with opposite creative abilities and higher values of task-induced coherence changes in the anterior regions of the left hemisphere and posterior regions of the right hemisphere in high-creative in comparison with low-creative men. The findings are discussed in terms of different cognitive strategies used by men and women that may have the same results in creative problem solving.

  20. Spectral analysis of neocortical and hippocampal EEG in the protein malnourished rat.

    PubMed

    Bronzino, J D; Austin, K; Siok, C J; Cordova, C; Morgane, P J

    1983-06-01

    In these studies, power spectral analysis techniques were utilized to quantify changes in the cortical and hippocampal EEG obtained from rats reared on either an 8% or 25% casein diet as they mature from 14 to 22 days of age. Analyses of the power spectral data obtained from the frontal cortex of rats reared on the 25% casein diet during this preweaning period (14-22 days) indicated increases in the power in the 0.5-3.5 c/sec frequency band primarily during slow-wave sleep. Prenatal protein malnutrition (8% casein diet) significantly reduced the low frequency power content in the cortical EEG obtained during slow-wave sleep at 18 and 22 days of age. Analyses of power spectral data obtained from the hippocampal EEG during REM sleep also revealed developmental and diet-related differences. The frequency at which the peak power occurs in the theta band (4-11 c/sec) was found to increase normally in a linear fashion from 14 to 22 days of age (from 4.4 to 5.5 c/sec) in rats reared on the 25% casein diet. In addition, power in the 4-7 c/sec band significantly increased during this preweaning period. Prenatal protein malnutrition significantly slowed the development of theta frequency and produced higher values of power in the component of theta rhythm. Finally, vigilance profiles showed that rats normally progress from 14 days of age when REM sleep dominates their vigilance profile, to 22 days of age when they spend significantly more time in slow-wave sleep. Prenatal protein malnutrition retards this normal developmental sequence by significantly reducing the REM sleep time at 14 and 18 days of age and increasing the time spend in aroused waking at both these ages. However, at the time of weaning, i.e., at 22 days of age, these differences in sleep-waking behavior were no longer observed to be significant.

  1. A systematic review of the neurophysiology of mindfulness on EEG oscillations.

    PubMed

    Lomas, Tim; Ivtzan, Itai; Fu, Cynthia H Y

    2015-10-01

    Mindfulness meditation has been purported to be a beneficial practice for wellbeing. It would therefore be expected that the neurophysiology of mindfulness would reflect this impact on wellbeing. However, investigations of the effects of mindfulness have generated mixed reports of increases, decreases, as well as no differences in EEG oscillations in comparison with a resting state and a variety of tasks. We have performed a systematic review of EEG studies of mindfulness meditation in order to determine any common effects and to identify factors which may impact on the effects. Databases were reviewed from 1966 to August 2015. Eligibility criteria included empirical quantitative analyses of mindfulness meditation practice and EEG measurements acquired in relation to practice. A total of 56 papers met the eligibility criteria and were included in the systematic review, consisting of a total 1715 subjects: 1358 healthy individuals and 357 individuals with psychiatric diagnoses. Studies were principally examined for power outcomes in each bandwidth, in particular the power differentials between mindfulness and a control state, as well as outcomes relating to hemispheric asymmetry and event-related potentials. The systematic review revealed that mindfulness was most commonly associated with enhanced alpha and theta power as compared to an eyes closed resting state, although such outcomes were not uniformly reported. No consistent patterns were observed with respect to beta, delta and gamma bandwidths. In summary, mindfulness is associated with increased alpha and theta power in both healthy individuals and in patient groups. This co-presence of elevated alpha and theta may signify a state of relaxed alertness which is conducive to mental health.

  2. Pre-stimulus BOLD-network activation modulates EEG spectral activity during working memory retention.

    PubMed

    Kottlow, Mara; Schlaepfer, Anthony; Baenninger, Anja; Michels, Lars; Brandeis, Daniel; Koenig, Thomas

    2015-01-01

    Working memory (WM) processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health. We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods. Four temporally coherent networks (TCNs)-the default mode network (DMN), the dorsal attention, the right and the left WM network-were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks' pre-stimulus activation upon retention-related EEG activity in the theta, alpha, and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing. We were able to replicate two well-known load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be "online" synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals.

  3. Longitudinal sleep EEG trajectories indicate complex patterns of adolescent brain maturation.

    PubMed

    Feinberg, Irwin; Campbell, Ian G

    2013-02-15

    New longitudinal sleep data spanning ages 6-10 yr are presented and combined with previous data to analyze maturational trajectories of delta and theta EEG across ages 6-18 yr in non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM delta power (DP) increased from age 6 to age 8 yr and then declined. Its highest rate of decline occurred between ages 12 and 16.5 yr. We attribute the delta EEG trajectories to changes in synaptic density. Whatever their neuronal underpinnings, these age curves can guide research into the molecular-genetic mechanisms that underlie adolescent brain development. The DP trajectories in NREM and REM sleep differed strikingly. DP in REM did not initially increase but declined steadily from age 6 to age 16 yr. We hypothesize that the DP decline in REM reflects maturation of the same brain arousal systems that eliminate delta waves in waking EEG. Whereas the DP age curves differed in NREM and REM sleep, theta age curves were similar in both, roughly paralleling the age trajectory of REM DP. The different maturational curves for NREM delta and theta indicate that they serve different brain functions despite having similar within-sleep dynamics and responses to sleep loss. Period-amplitude analysis of NREM and REM delta waveforms revealed that the age trends in DP were driven more by changes in wave amplitude rather than incidence. These data further document the powerful and complex link between sleep and brain maturation. Understanding this relationship would shed light on both brain development and the function of sleep.

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

    PubMed

    Aftanas, Ljubomir; Golosheykin, Semen

    2005-06-01

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

  5. The EEG of tropical encephalopathies.

    PubMed

    Mallewa, Macpherson; Birbeck, Gretchen L

    2013-10-01

    In addition to encountering most of the conditions treated by clinicians in the West, clinicians in the tropics are faced with unique tropical encephalopathies. These are largely but not entirely infectious in nature. Despite the relatively low cost of EEG technology, it remains unavailable in many low-income tropical settings even at the tertiary care level. Where available, the EEG recordings and interpretation are often of unacceptable quality. Nonetheless, there are existing data on the EEG patterns seen in malaria and a number of tropical viral, bacterial, and parasitic infestations.

  6. Quantitative EEG (QEEG) Measures Differentiate Parkinson's Disease (PD) Patients from Healthy Controls (HC)

    PubMed Central

    Chaturvedi, Menorca; Hatz, Florian; Gschwandtner, Ute; Bogaarts, Jan G.; Meyer, Antonia; Fuhr, Peter; Roth, Volker

    2017-01-01

    Objectives: To find out which Quantitative EEG (QEEG) parameters could best distinguish patients with Parkinson's disease (PD) with and without Mild Cognitive Impairment from healthy individuals and to find an optimal method for feature selection. Background: Certain QEEG parameters have been seen to be associated with dementia in Parkinson's and Alzheimer's disease. Studies have also shown some parameters to be dependent on the stage of the disease. We wanted to investigate the differences in high-resolution QEEG measures between groups of PD patients and healthy individuals, and come up with a small subset of features that could accurately distinguish between the two groups. Methods: High-resolution 256-channel EEG were recorded in 50 PD patients (age 68.8 ± 7.0 year; female/male 17/33) and 41 healthy controls (age 71.1 ± 7.7 year; female/male 20/22). Data was processed to calculate the relative power in alpha, theta, delta, beta frequency bands across the different regions of the brain. Median, peak frequencies were also obtained and alpha1/theta ratios were calculated. Machine learning methods were applied to the data and compared. Additionally, penalized Logistic regression using LASSO was applied to the data in R and a subset of best-performing features was obtained. Results: Random Forest and LASSO were found to be optimal methods for feature selection. A group of six measures selected by LASSO was seen to have the most effect in differentiating healthy individuals from PD patients. The most important variables were the theta power in temporal left region and the alpha1/theta ratio in the central left region. Conclusion: The penalized regression method applied was helpful in selecting a small group of features from a dataset that had high multicollinearity. PMID:28167911

  7. Posterior versus Frontal Theta Activity Indexes Approach Motivation during Affective Autobiographical Memories

    PubMed Central

    Walden, Keegan; Pornpattananangkul, Narun; Curlee, Alexandria; McAdams, Dan P.; Nusslock, Robin

    2016-01-01

    Research has recently identified a promising neurophysiological marker of approach motivation involving posterior versus frontal (Pz-Fz) electroencephalographic (EEG) theta activity (PFTA; Wacker, Chavanon, & Stemmler, 2006). Preliminary evidence indicates that PFTA is modulated by dopaminergic activity thought to underlie appetitive tendencies, and that it indexes self-reported Behavioral Approach System (BAS) sensitivity. To date, research has largely relied on resting indices of PFTA and has yet to examine the relationship between PFTA and specific approach-related affective states generated by emotionally salient laboratory tasks. Accordingly, the present study evaluated PFTA both at rest and during an ecologically valid autobiographical memory task in which participants recalled personal life experiences involving a goal-striving, an anxious apprehension, a low-point (i.e., difficult) and a neutral memory while EEG data were recorded. In line with prediction, elevated PFTA was observed during both goal-striving and anxious apprehension autobiographical memories. PFTA was particularly elevated during anxious apprehension memories coded as being high on approach-related tendencies. Elevated PFTA during anxious apprehension is consistent with a growing literature indicating that anxious apprehension is associated with elevated approach and reward-related brain function. Lastly, elevated resting PFTA was positively correlated with self-reported trait anger, a negatively valenced emotion characterized by approach-related tendencies. Results have implications for a) enhancing our understanding of the neurophysiology of approach-related emotions, b) establishing PFTA as an index of appetitive motivational states, and c) clarifying our understanding of the neurophysiology and approach-related tendencies associated with both anxious apprehension and anger. PMID:25245178

  8. Posterior versus frontal theta activity indexes approach motivation during affective autobiographical memories.

    PubMed

    Walden, K; Pornpattananangkul, N; Curlee, A; McAdams, D P; Nusslock, R

    2015-03-01

    Research has recently identified a promising neurophysiological marker of approach motivation involving posterior versus frontal (Pz - Fz) electroencephalographic (EEG) theta activity PFTA; Wacker, Chavanon, & Stemmler (Journal of Personality and Social Psychology 91:171-187, 2006). Preliminary evidence indicated that PFTA is modulated by dopaminergic activity, thought to underlie appetitive tendencies, and that it indexes self-reported behavioral activation system (BAS) sensitivity. To date, research has largely relied on resting indices of PFTA and has yet to examine the relationship between PFTA and specific approach-related affective states generated by emotionally salient laboratory tasks. Accordingly, the present study evaluated PFTA both at rest and during an ecologically valid autobiographical memory task in which participants recalled personal life experiences involving a goal-striving, an anxious apprehension, a low-point (i.e., difficult), and a neutral memory while EEG data were recorded. In line with prediction, elevated PFTA was observed during both goal-striving and anxious apprehension autobiographical memories. PFTA was particularly elevated during anxious apprehension memories coded as being high on approach-related tendencies. Elevated PFTA during anxious apprehension is consistent with a growing literature indicating that anxious apprehension is associated with elevated approach- and reward-related brain function. Lastly, elevated resting PFTA was positively correlated with self-reported trait anger, a negatively valenced emotion characterized by approach-related tendencies. These results have implications for (a) enhancing our understanding of the neurophysiology of approach-related emotions, (b) establishing PFTA as an index of appetitive motivational states, and (c) clarifying our understanding of the neurophysiology and approach-related tendencies associated with both anxious apprehension and anger.

  9. Application of alpha/theta neurofeedback and heart rate variability training to young contemporary dancers: state anxiety and creativity.

    PubMed

    Gruzelier, J H; Thompson, T; Redding, E; Brandt, R; Steffert, T

    2014-07-01

    As one in a series on the impact of EEG-neurofeedback in the performing arts, we set out to replicate a previous dance study in which alpha/theta (A/T) neurofeedback and heart rate variability (HRV) biofeedback enhanced performance in competitive ballroom dancers compared with controls. First year contemporary dance conservatoire students were randomised to the same two psychophysiological interventions or a choreology instruction comparison group or a no-training control group. While there was demonstrable neurofeedback learning, there was no impact of the three interventions on dance performance as assessed by four experts. However, HRV training reduced anxiety and the reduction correlated with improved technique and artistry in performance; the anxiety scale items focussed on autonomic functions, especially cardiovascular activity. In line with the putative impact of hypnogogic training on creativity A/T training increased cognitive creativity with the test of unusual uses, but not insight problems. Methodological and theoretical implications are considered.

  10. Changes in quantitative EEG absolute power during the task of catching an object in free fall.

    PubMed

    Machado, Sergio; Portella, Cláudio Elidio; Silva, Julio Guilherme; Velasques, Bruna; Terra, Patrícia; Vorkapic, Camila Ferreira; Silva, Vernon Furtado da; Miana, Luis; Basile, Luis; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro

    2007-09-01

    The aim of this study was to verify changes in absolute power (qEEG), in theta, during the catch of a free falling object. The sample consisted of 10 healthy individuals, of both genders, with ages between 25 and 40 years. A three-way ANOVA followed by Post-Hoc analysis was applied. The results demonstrated main effects for time and position. In conclusion, a motor task that involves expectation produces deactivation of non-relevant areas in the ipsilateral hemisphere of the active limb. On the other hand, the patterns of results showed activation in areas responsible for planning and selection of motor repertoires in the contralateral hemisphere.

  11. [An analysis of EEG rhythm changes following micropolarization of several brain structures].

    PubMed

    Blank, Iu A

    1976-01-01

    With the aid of the EEG special statistical analysis, micropolarization of the temporal cortex of hypothalamus was shown to entail abrupt alterations of the theta-, alpha-, and beta-rhythms in the temporal and motor cortex, hypothalamus, and the midbrain RF. The changes of the biorhythms (their correlation, thresholds of occurring, connection of the local and distant shifts) are regarded as reflecting some fine regulation of the structures' functional condition as well as mutual influences of the cortex and the deep brain structures which tell on modulation of mnemic processes.

  12. Theta-gamma coupling reflects the interaction of bottom-up and top-down processes in speech perception in children.

    PubMed

    Wang, Juan; Gao, Danqi; Li, Duan; Desroches, Amy S; Liu, Li; Li, Xiaoli

    2014-11-15

    This study investigates how the interaction of different brain oscillations (particularly theta-gamma coupling) modulates the bottom-up and top-down processes during speech perception. We employed a speech perception paradigm that manipulated the congruency between a visually presented picture and an auditory stimulus and asked participants to judge whether they matched or mismatched. A group of children (mean age 10 years, 5 months) participated in this study and their electroencephalographic (EEG) data were recorded while performing the experimental task. It was found that in comparison with mismatch condition, match condition facilitated speech perception by eliciting greater theta-gamma coupling in the frontal area and smaller theta-gamma coupling in the left temporal area. These findings suggested that a top-down facilitation effect from congruent visual pictures engaged different mechanisms in low-level sensory (temporal) regions and high-level linguistic and decision (frontal) regions. Interestingly, hemispheric asymmetry is with higher theta-gamma coupling in the match condition in the right hemisphere and higher theta-gamma coupling in the mismatch condition in the left hemisphere. This indicates that a fast global processing strategy and a slow detailed processing strategy were differentially adopted in the match and mismatch conditions. This study provides new insight into the mechanisms of speech perception from the interaction of different oscillatory activities and provides neural evidence for theories of speech perception allowing for top-down feedback connections. Furthermore, it sheds light on children's speech perception development by showing a similar pattern of integration of bottom-up and top-down information during speech perception as previous studies have revealed in adults.

  13. Use of electroencephalography (EEG) to assess CNS changes produced by pesticides with different modes of action: Effects of permethrin, deltamethrin, fipronil, imidacloprid, carbaryl, and triadimefon

    SciTech Connect

    Freeborn, Danielle L. McDaniel, Katherine L. Moser, Virginia C. Herr, David W.

    2015-01-15

    The electroencephalogram (EEG) is an apical measure, capable of detecting changes in brain neuronal activity produced by internal or external stimuli. We assessed whether pesticides with different modes of action produced different changes in the EEG of adult male Long–Evans rats. The EEG was recorded using two montages (visual cortex referenced to the cerebellum and to the frontal cortex) in unrestrained rats at the time of peak behavioral effects. Pesticides included: permethrin and deltamethrin (Type I and Type II pyrethroids; 2 h), fipronil (single and repeated doses; phenylpyrazole; 6 h), imidacloprid (neonicotinoid; 2 h), carbaryl (carbamate; 0.5 h), and triadimefon (triazole; 1 h), using dosages that produced approximately an ED{sub 30} or an ED{sub 50}–ED{sub 80} change in motor activity. Permethrin (43, 100 mg/kg) increased amplitudes or areas (delta, alpha, or gamma bands) in the EEG. Deltamethrin (2.5, 5.5 mg/kg) reduced the amplitudes or areas of the delta, theta, alpha, beta, and gamma bands, but the changes were not dose-related. A single treatment with fipronil (25, 50 mg/kg, but not 5, 10 mg/kg) decreased gamma band area. Additional changes in the delta, theta, and gamma bands were observed when fipronil (5, 10 mg/kg) was administered for 14 days. Imidacloprid (50, 100 mg/kg) did not alter the EEG. Carbaryl (10, 50 mg/kg) decreased theta area, and decreased delta and increased beta frequency. Triadimefon (75, 150 mg/kg) produced minimal changes in the EEG. The results show that the EEG is affected differently by approximately equipotent doses of pesticides with different modes of action. - Highlights: • Pesticides with different modes of action have different effects on in vivo rodent EEG. • The EEG was also changed differently after single vs. repeated treatment with fipronil. • The data suggest that EEG may be used as an apical measure for detecting chemical effects on the central nervous system.

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

    PubMed

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

    2016-03-01

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

  15. The phase of ongoing EEG oscillations predicts visual perception.

    PubMed

    Busch, Niko A; Dubois, Julien; VanRullen, Rufin

    2009-06-17

    Oscillations are ubiquitous in electrical recordings of brain activity. While the amplitude of ongoing oscillatory activity is known to correlate with various aspects of perception, the influence of oscillatory phase on perception remains unknown. In particular, since phase varies on a much faster timescale than the more sluggish amplitude fluctuations, phase effects could reveal the fine-grained neural mechanisms underlying perception. We presented brief flashes of light at the individual luminance threshold while EEG was recorded. Although the stimulus on each trial was identical, subjects detected approximately half of the flashes (hits) and entirely missed the other half (misses). Phase distributions across trials were compared between hits and misses. We found that shortly before stimulus onset, each of the two distributions exhibited significant phase concentration, but at different phase angles. This effect was strongest in the theta and alpha frequency bands. In this time-frequency range, oscillatory phase accounted for at least 16% of variability in detection performance and allowed the prediction of performance on the single-trial level. This finding indicates that the visual detection threshold fluctuates over time along with the phase of ongoing EEG activity. The results support the notion that ongoing oscillations shape our perception, possibly by providing a temporal reference frame for neural codes that rely on precise spike timing.

  16. 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.

  17. [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.

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

    NASA Technical Reports Server (NTRS)

    Bert, J.; Collomb, H.

    1980-01-01

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

  19. Preliminary Study on Quantitative Sleep EEG Characteristics in Patients with Schizophrenia

    PubMed Central

    Oh, Seong Min; Kim, Jong Won; Choi, Jae Won; Jeong, Do-Un

    2017-01-01

    We used quantitative electroencephalography (EEG) spectral analysis to compare activity in the bilateral frontal, central, and occipital areas in nine patients with schizophrenia and ten healthy control subjects during standard nocturnal polysomnography. Patients with schizophrenia had longer sleep latency than controls. In N2 sleep, the patients had significantly lower 0.5–1 Hz power and higher theta power in the left frontal region, and higher beta power in the left occipital region than did control subjects. In N3 sleep, the patients with schizophrenia had significantly higher alpha power in the left occipital region than did controls. These findings show distinctive EEG sleep patterns in patients with schizophrenia, which may reflect brain dysfunction or medication effects. PMID:28326122

  20. Resting state EEG power, intra-hemisphere and inter-hemisphere coherence in bipolar disorder

    NASA Astrophysics Data System (ADS)

    Handayani, Nita; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, Warsito P.

    2017-02-01

    This paper examines the differences of EEG power and coherence between bipolar disorder patients and healthy subjects in the resting state. Observations are focused on the prefrontal cortex area by calculating intra-hemisphere and inter-hemisphere coherence. EEG data acquisition are conducted by using wireless Emotiv Epoc on AF3, AF4, FC5, FC6, F7 and F8 channels. The power spectral analysis shows that in bipolar disoder there is an increase of power in the delta, theta and beta frequencies, and power decrease in the alpha frequency. The coherence test results show that both intra-hemisphere and inter-hemisphere coherence in bipolar disorder patients are lower than healthy subjects. This shows the lack of brain synchronization in bipolar disorder patients.

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

    PubMed

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

    2011-05-01

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

  2. Quantum modular forms, mock modular forms, and partial theta functions

    NASA Astrophysics Data System (ADS)

    Kimport, Susanna

    Defined by Zagier in 2010, quantum modular forms have been the subject of an explosion of recent research. Many of these results are aimed at discovering examples of these functions, which are defined on the rational numbers and have "nice" modularity properties. Though the subject is in its early stages, numerous results (including Zagier's original examples) show these objects naturally arising from many areas of mathematics as limits of other modular-like functions. One such family of examples is due to Folsom, Ono, and Rhoades, who connected these new objects to partial theta functions (introduced by Rogers in 1917) and mock modular forms (about which there is a rich theory, whose origins date back to Ramanujan in 1920). In this thesis, we build off of the work of Folsom, Ono, and Rhoades by providing an infinite family of quantum modular forms of arbitrary positive half-integral weight. Further, this family of quantum modular forms "glues" mock modular forms to partial theta functions and is constructed from a so-called "universal" mock theta function by extending a method of Eichler and Zagier (originally defined for holomorphic Jacobi forms) into a non-holomorphic setting. In addition to the infinite family, we explore the weight 1/2 and 3/2 functions in more depth. For both of these weights, we are able to explicitly write down the quantum modular form, as well as the corresponding "errors to modularity," which can be shown to be Mordell integrals of specific theta functions and, as a consequence, are real-analytic functions. Finally, we turn our attention to the partial theta functions associated with these low weight examples. Berndt and Kim provide asymptotic expansions for a certain class of partial theta functions as q approaches 1 radially within the unit disk. Here, we extend this work to not only obtain asymptotic expansions for this class of functions as q approaches any root of unity, but also for a certain class of derivatives of these functions

  3. EEG default mode network in the human brain: spectral regional field powers.

    PubMed

    Chen, Andrew C N; Feng, Weijia; Zhao, Huixuan; Yin, Yanling; Wang, Peipei

    2008-06-01

    Eyes-closed (EC) and eyes-open (EO) are essential behaviors in mammalians, including man. At resting EC-EO state, brain activity in the default mode devoid of task-demand has recently been established in fMRI. However, the corresponding comprehensive electrophysiological conditions are little known even though EEG has been recorded in humans for nearly 80 years. In this study, we examined the spatial characteristics of spectral distribution in EEG field powers, i.e., sitting quietly with an EC and EO resting state of 3 min each, measured with high-density 128-ch EEG recording and FFT signal analyses in 15 right-handed healthy college females. Region of interest was set at a threshold at 90% of the spectral effective value to delimit the dominant spatial field power of effective energy in brain activity. Low-frequency delta (0.5-3.5 Hz) EEG field power was distributed at the prefrontal area with great expansion of spatial field and enhancement of field power (t=-2.72, p<0.02) from the EC to the EO state. Theta (4-7 Hz) EEG field power was distributed over the fronto-central area and leaned forward from EC to the EO state but with drastic reduction in field power (t=4.04, p<0.01). The middle-frequency alpha-1 (7.5-9.5 Hz) and alpha-2 (10-12 Hz) EEG powers exhibited bilateral distribution over the posterior areas with an anterior field in lower alpha-1. Both showed significantly reduction of field powers (respectively, W=120, p<0.001 for alpha-1; t=4.12, p<0.001 for alpha-2) from EC to the EO state. Beta-1 (13-23 Hz) exhibited a similar spatial region over the posterior area as in alpha-2 and showed reduction of field power (t=4.42, p<0.001) from EC to the EO state. In contrast, high-frequency beta-2 and gamma band exhibited similar, mainly prefrontal distribution in field power, and exhibited no change from EC to the EO state. Corresponding correlation analyses indicated significant group association between EC and EO only in the field powers of delta (r=0.95, p<0

  4. Amyloid Beta Peptides Differentially Affect Hippocampal Theta Rhythms In Vitro

    PubMed Central

    Gutiérrez-Lerma, Armando I.; Ordaz, Benito; Peña-Ortega, Fernando

    2013-01-01

    Soluble amyloid beta peptide (Aβ) is responsible for the early cognitive dysfunction observed in Alzheimer's disease. Both cholinergically and glutamatergically induced hippocampal theta rhythms are related to learning and memory, spatial navigation, and spatial memory. However, these two types of theta rhythms are not identical; they are associated with different behaviors and can be differentially modulated by diverse experimental conditions. Therefore, in this study, we aimed to investigate whether or not application of soluble Aβ alters the two types of theta frequency oscillatory network activity generated in rat hippocampal slices by application of the cholinergic and glutamatergic agonists carbachol or DHPG, respectively. Due to previous evidence that oscillatory activity can be differentially affected by different Aβ peptides, we also compared Aβ25−35 and Aβ1−42 for their effects on theta rhythms in vitro at similar concentrations (0.5 to 1.0 μM). We found that Aβ25−35 reduces, with less potency than Aβ1−42, carbachol-induced population theta oscillatory activity. In contrast, DHPG-induced oscillatory activity was not affected by a high concentration of Aβ25−35 but was reduced by Aβ1−42. Our results support the idea that different amyloid peptides might alter specific cellular mechanisms related to the generation of specific neuronal network activities, instead of exerting a generalized inhibitory effect on neuronal network function. PMID:23878547

  5. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning

    PubMed Central

    Hoffmann, Loren C.; Cicchese, Joseph J.; Berry, Stephen D.

    2015-01-01

    Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3–12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3–7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning. PMID:25918501

  6. EEG correlates of fatigue during administration of a neuropsychological test battery

    PubMed Central

    Barwick, Fiona; Arnett, Peter; Slobounov, Semyon

    2011-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  8. Affective attitudes to face images associated with intracerebral EEG source location before face viewing.

    PubMed

    Pizzagalli, D; Koenig, T; Regard, M; Lehmann, D

    1999-01-01

    We investigated whether different, personality-related affective attitudes are associated with different brain electric field (EEG) sources before any emotional challenge (stimulus exposure). A 27-channel EEG was recorded in 15 subjects during eyes-closed resting. After recording, subjects rated 32 images of human faces for affective appeal. The subjects in the first (i.e., most negative) and fourth (i.e., most positive) quartile of general affective attitude were further analyzed. The EEG data (mean=25+/-4. 8 s/subject) were subjected to frequency-domain model dipole source analysis (FFT-Dipole-Approximation), resulting in 3-dimensional intracerebral source locations and strengths for the delta-theta, alpha, and beta EEG frequency band, and for the full range (1.5-30 Hz) band. Subjects with negative attitude (compared to those with positive attitude) showed the following source locations: more inferior for all frequency bands, more anterior for the delta-theta band, more posterior and more right for the alpha, beta and 1.5-30 Hz bands. One year later, the subjects were asked to rate the face images again. The rating scores for the same face images were highly correlated for all subjects, and original and retest affective mean attitude was highly correlated across subjects. The present results show that subjects with different affective attitudes to face images had different active, cerebral, neural populations in a task-free condition prior to viewing the images. We conclude that the brain functional state which implements affective attitude towards face images as a personality feature exists without elicitors, as a continuously present, dynamic feature of brain functioning.

  9. Reward Dependent Invigoration Relates to Theta Oscillations and Is Predicted by Dopaminergic Midbrain Integrity in Healthy Elderly

    PubMed Central

    Steiger, Tineke K.; Bunzeck, Nico

    2017-01-01

    Motivation can have invigorating effects on behavior via dopaminergic neuromodulation. While this relationship has mainly been established in theoretical models and studies in younger subjects, the impact of structural declines of the dopaminergic system during healthy aging remains unclear. To investigate this issue, we used electroencephalography (EEG) in healthy young and elderly humans in a reward-learning paradigm. Specifically, scene images were initially encoded by combining them with cues predicting monetary reward (high vs. low reward). Subsequently, recognition memory for the scenes was tested. As a main finding, we can show that response times (RTs) during encoding were faster for high reward predicting images in the young but not elderly participants. This pattern was resembled in power changes in the theta-band (4–7 Hz). Importantly, analyses of structural MRI data revealed that individual reward-related differences in the elderlies’ response time could be predicted by the structural integrity of the dopaminergic substantia nigra (SN; as measured by magnetization transfer (MT)). These findings suggest a close relationship between reward-based invigoration, theta oscillations and age-dependent changes of the dopaminergic system. PMID:28174533

  10. A multimodal approach to estimating vigilance using EEG and forehead EOG

    NASA Astrophysics Data System (ADS)

    Zheng, Wei-Long; Lu, Bao-Liang

    2017-04-01

    Objective. Covert aspects of ongoing user mental states provide key context information for user-aware human computer interactions. In this paper, we focus on the problem of estimating the vigilance of users using EEG and EOG signals. Approach. The PERCLOS index as vigilance annotation is obtained from eye tracking glasses. To improve the feasibility and wearability of vigilance estimation devices for real-world applications, we adopt a novel electrode placement for forehead EOG and extract various eye movement features, which contain the principal information of traditional EOG. We explore the effects of EEG from different brain areas and combine EEG and forehead EOG to leverage their complementary characteristics for vigilance estimation. Considering that the vigilance of users is a dynamic changing process because the intrinsic mental states of users involve temporal evolution, we introduce continuous conditional neural field and continuous conditional random field models to capture dynamic temporal dependency. Main results. We propose a multimodal approach to estimating vigilance by combining EEG and forehead EOG and incorporating the temporal dependency of vigilance into model training. The experimental results demonstrate that modality fusion can improve the performance compared with a single modality, EOG and EEG contain complementary information for vigilance estimation, and the temporal dependency-based models can enhance the performance of vigilance estimation. From the experimental results, we observe that theta and alpha frequency activities are increased, while gamma frequency activities are decreased in drowsy states in contrast to awake states. Significance. The forehead setup allows for the simultaneous collection of EEG and EOG and achieves comparative performance using only four shared electrodes in comparison with the temporal and posterior sites.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    PubMed

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

    2014-12-01

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

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

    PubMed

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

    2015-01-01

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

  14. Changes in human EEG caused by low level modulated microwave stimulation.

    PubMed

    Hinrikus, Hiie; Parts, Maie; Lass, Jaanus; Tuulik, Viiu

    2004-09-01

    This study focuses on the effect of low level microwave radiation on human EEG alpha and theta rhythms. During the experiment, 20 healthy volunteers were exposed to a 450 MHz microwaves with 7 Hz on-off modulation. The field power density at the scalp was 0.16 mW/cm2. Signals from the following EEG channels were used: FP1, FP2, P3, P4, T3, T4, O1, and O2. The experimental protocol consisted of one cycle of short term photic and ten cycles of the repetitive microwave stimulation. The changes caused by photic as well as microwave stimulation were more regular on the alpha rhythm. In the majority of cases, photic stimulation caused changes in the EEG energy level in the occipital and microwave stimulation in the frontal region. Our experimental results demonstrated that microwave stimulation effects became apparent, starting from the third stimulation cycle. Changes varied strongly from subject to subject. Therefore, photic and microwave exposure did not cause statistically significant changes in the EEG activity level for the whole group. For some subjects, clear tendencies of changes in microwave on-off cycles were noticeable.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  16. Functional organization of different brain areas during convergent and divergent thinking: an EEG investigation.

    PubMed

    Razoumnikova, O M

    2000-09-01

    This study examined the task-related changes in EEG patterns during the experimental condition of convergent and divergent thinking in 36 healthy male subjects. EEG was recorded from 16 sites (10/20 system). After FFT a power was calculated for all 16 loci, and a coherence was estimated for all 120 electrode pairs in six frequency bands (4-30 Hz). Different patterns of the significant changes for the obtained EEG parameters were found during the two thinking types. When compared with the rest, both mental experiences produced the significant desynchronization of alpha1,2 rhythms. At the same time, the convergent thinking induced coherence increases in the θ1 band that were more caudal and right-sided, whereas divergent thinking showed mainly amplitude decreases in the caudal regions of the cortex in theta1,2 bands and the massive increases of a amplitude and coherence in the beta2 indicating a close interaction between both hemispheres. Distinct task-related discrepancies of EEG pattern in the beta2 band between the subjects divided into groups of good and bad performers of divergent thinking are also found. Good performance is related to the special organization of the cerebral areas in the beta2 band: (i) increased functional connectivity of central-parietal areas of both hemispheres; and (ii) greater ipsilateral connections between the cortex regions of the right hemisphere.

  17. EEG inter/intra-hemispheric coherence and asymmetric responses to visual stimulations.

    PubMed

    Cvetkovic, Dean; Cosic, Irena

    2009-10-01

    This study has attempted to increase the meaning and significance of findings in the experimental areas of electroencephalographic (EEG) visual or photic driving. The aim of this study was to investigate whether the visual stimulation at particular extremely low frequency order could possibly induce changes in the corresponding EEG frequency bands by examining the functional connectedness between brain regions. This was evaluated by applying the improved experimental protocol and objective using non-parametric spectral estimation coherence algorithm. The findings from our study revealed a significantly higher coherence in the EEG beta2 band (16.6 Hz) corresponding to 16.66 Hz visual stimulation, suggesting a high inter-hemispheric functional connectivity during visual stimulus. A significant increase was revealed during 50 Hz visual stimulation at gamma band and a decrease during 4 Hz visual stimulation at theta band, linked with a substantial transitional shift in predominance from anterior to posterior relative power. This study may also increase the awareness of EEG visual driving response studies in clinical practice to uncover potential neurophysiologic abnormalities.

  18. [EEG coherence during unconscious visual set under conditions of increased motivation of subjects].

    PubMed

    Kurova, N S; Cheremushkin, E A; Ashkinazi, M L

    2003-01-01

    Prestimulus EEG was recorded in the state of "operative rest" after the instruction and at the stages of formation, actualization, and extinction of unconscious visual set to perception of unequal circles. Two motivation conditions were used: (1) subjects were promised to be rewarded with a small money price for each correct response (a "general" rise of motivation) and (2) only correct assessments of stimuli of a certain kind were rewarded (a "selective" rise of motivation). In both conditions, additional motivation of subjects to the results of their performance led to an increase in EEG coherence most pronounced in the theta and alpha 1 frequency ranges in the left temporal area of the cortex. During the "general" rise of motivation the EEG coherence (as compared to the control group) was higher in a greater number of derivation pairs than during the "selective" rise. EEG coherence in "motivated" subjects was increased already at the stage of operative rest. Later on, at the set stages, no significant changes were revealed. Thus, the realized set formed by the verbal instruction, which increased motivation of subjects to the results of their performance, produced substantially more prominent changes in coherence of cortical potentials than the unconscious set formed during perception of visual stimuli.

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

    PubMed Central

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

    2015-01-01

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

  20. Cerebellar theta burst stimulation modulates the neural activity of interconnected parietal and motor areas

    PubMed Central

    Casula, Elias Paolo; Pellicciari, Maria Concetta; Ponzo, Viviana; Stampanoni Bassi, Mario; Veniero, Domenica; Caltagirone, Carlo; Koch, Giacomo

    2016-01-01

    Voluntary movement control and execution are regulated by the influence of the cerebellar output over different interconnected cortical areas, through dentato-thalamo connections. In the present study we applied transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess the effects of cerebellar theta-burst stimulation (TBS) over the controlateral primary motor cortex (M1) and posterior parietal cortex (PPC) in a group of healthy volunteers. We found a TBS-dependent bidirectional modulation over TMS-evoked activity; specifically, cTBS increased whereas iTBS decreased activity between 100 and 200 ms after TMS, in a similar manner over both M1 and PPC areas. On the oscillatory domain, TBS induced specific changes over M1 natural frequencies of oscillation: TMS-evoked alpha activity was decreased by cTBS whereas beta activity was enhanced by iTBS. No effects were observed after sham stimulation. Our data provide novel evidence showing that the cerebellum exerts its control on the cortex likely by impinging on specific set of interneurons dependent on GABA-ergic activity. We show that cerebellar TBS modulates cortical excitability of distant interconnected cortical areas by acting through common temporal, spatial and frequency domains. PMID:27796359

  1. Event-related delta, theta, alpha and gamma correlates to auditory oddball processing during Vipassana meditation.

    PubMed

    Cahn, B Rael; Delorme, Arnaud; Polich, John

    2013-01-01

    Long-term Vipassana meditators sat in meditation vs. a control (instructed mind wandering) states for 25 min, electroencephalography (EEG) was recorded and condition order counterbalanced. For the last 4 min, a three-stimulus auditory oddball series was presented during both meditation and control periods through headphones and no task imposed. Time-frequency analysis demonstrated that meditation relative to the control condition evinced decreased evoked delta (2-4 Hz) power to distracter stimuli concomitantly with a greater event-related reduction of late (500-900 ms) alpha-1 (8-10 Hz) activity, which indexed altered dynamics of attentional engagement to distracters. Additionally, standard stimuli were associated with increased early event-related alpha phase synchrony (inter-trial coherence) and evoked theta (4-8 Hz) phase synchrony, suggesting enhanced processing of the habituated standard background stimuli. Finally, during meditation, there was a greater differential early-evoked gamma power to the different stimulus classes. Correlation analysis indicated that this effect stemmed from a meditation state-related increase in early distracter-evoked gamma power and phase synchrony specific to longer-term expert practitioners. The findings suggest that Vipassana meditation evokes a brain state of enhanced perceptual clarity and decreased automated reactivity.

  2. Normalisation of frontal theta activity following methylphenidate treatment in adult attention-deficit/hyperactivity disorder.

    PubMed

    Skirrow, Caroline; McLoughlin, Grainne; Banaschewski, Tobias; Brandeis, Daniel; Kuntsi, Jonna; Asherson, Philip

    2015-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is associated with cognitive performance and functional brain changes that are sensitive to task conditions, indicating a role for dynamic impairments rather than stable cognitive deficits. Prominent hypotheses consistent with this observation are a failure to optimise brain arousal or activation states. Here we investigate cortical activation during different conditions. Using a sample of 41 non-comorbid adults with ADHD and 48 controls, we examine quantitative EEG activity during a resting state, a cued continuous performance test with flankers (CPT-OX) and the sustained attention to response task (SART). We further investigate the effects of methylphenidate in a subsample of 21 ADHD cases. Control participants showed a task-related increase in theta activity when engaged in cognitive tasks, primarily in frontal and parietal regions, which was absent in participants with ADHD. Treatment with methylphenidate resulted in normalisation of the resting state to task activation pattern. These findings suggest that ADHD in adults is associated with insufficient allocation of neuronal resources required for normal cortical activation commensurate with task demands. Further work is required to clarify the causal role of the deficit in cortical activation and provide a clearer understanding of the mechanisms involved.

  3. Working memory-related frontal theta activity is decreased under acute stress.

    PubMed

    Gärtner, Matti; Rohde-Liebenau, Lea; Grimm, Simone; Bajbouj, Malek

    2014-05-01

    Acute stress impairs prefrontal cortex (PFC) function and has detrimental effects on working memory (WM) performance. Converging evidence from electrophysiological studies suggests a close link between WM processes and frontal theta (FT) activity (4-8 Hz). However, the effect of stress on WM-related FT activity has not been investigated yet. To shed light on this topic we acquired EEG data from 31 healthy male subjects who underwent a stressful and a neutral control condition. In both conditions, they performed an n-back WM task at two different difficulty levels. Our results showed that WM-related FT activity was decreased under stress. Behaviorally, we found performance impairments under stress in the difficult task condition that were related to FT decreases. Increased cortisol levels indicated a successful moderate stress induction. These findings indicate that FT is a potential neurobiological marker for intact PFC functioning during WM and further supports the recently made assumption that FT acts in the PFC to optimize performance.

  4. Quantum Theta Functions and Gabor Frames for Modulation Spaces

    NASA Astrophysics Data System (ADS)

    Luef, Franz; Manin, Yuri I.

    2009-06-01

    Representations of the celebrated Heisenberg commutation relations in quantum mechanics (and their exponentiated versions) form the starting point for a number of basic constructions, both in mathematics and mathematical physics (geometric quantization, quantum tori, classical and quantum theta functions) and signal analysis (Gabor analysis). In this paper we will try to bridge the two communities, represented by the two co-authors: that of noncommutative geometry and that of signal analysis. After providing a brief comparative dictionary of the two languages, we will show, e.g. that the Janssen representation of Gabor frames with generalized Gaussians as Gabor atoms yields in a natural way quantum theta functions, and that the Rieffel scalar product and associativity relations underlie both the functional equations for quantum thetas and the Fundamental Identity of Gabor analysis.

  5. [EEG investigations in cognitive impairments].

    PubMed

    Szirmai, Imre; Kamondi, Anita

    2011-01-30

    The EEG is an indicator of all physiological and neuropsychological activity. The alpha rhythm was considered as a key phenomenon in research of human mentation from the discovery of EEG. Two methods are known for the estimation of cognitive deficit by the use of quantitative EEG (QEEG). The first is based on the hypothesis, that the mean values of the normal EEG from healthy volunteers can be used as reference, and deviation from the normal values of EEG parameters may suggest disease. This kind of "neurometry" was elaborated by R. E. John. The second method assesses event related (ER) transients evoked by somatosensory and mental stimuli. Quantity and localization of signals may refer to the functional state of the cortex. These reactions depend strongly on the test-paradigms. Recognition of the attention-intention cycle disclosed the physiological mechanism of ERD (event related desynchronisation) and ERS (event related synchronisation). In contrast with the classical "stimulus-reaction" model, both perception and voluntary movement are initiated by the brain itself, and not by the environment. Human behavior and conscious actions depend on the intention. QEEG analysis proved that the attention and intention localize in segregate areas of the brain. Both "static" and "dynamic" neurometric methods are able to differentiate the EEG records of demented patients from healthy controls, furthermore some dementias from each other. We conclude that with the help of sophisticated methods of QEEG analysis minimal functional deficit of the electrogenesis can be recognized, which could be helpful in the differential diagnosis Notwithstanding the EEG can not explain the evolution neither the normal or the diseased mental processes. The only "instrument" which is able to approach the human mind is the human cogitation itself with the aids of appropriate tests. The QEEG can be conclusive in the analysis of particular processes of mental activity, such as timing, state of

  6. Altered Intermittent Rhythmic Delta and Theta Activity in the Electroencephalographies of High Functioning Adult Patients with Autism Spectrum Disorder

    PubMed Central

    Endres, Dominique; Maier, Simon; Feige, Bernd; Posielski, Nicole A.; Nickel, Kathrin; Ebert, Dieter; Riedel, Andreas; Philipsen, Alexandra; Perlov, Evgeniy; Tebartz van Elst, Ludger

    2017-01-01

    Background: Autism spectrum disorder (ASD) is often associated with epilepsy. Previous studies have also shown increased rates of electroencephalographic (EEG) alteration in ASD patients without epilepsy. The aim of this study was to compare the rate of intermittent rhythmic delta and theta activity (IRDA/IRTA) events between high-functioning adult patients with ASD and matched healthy controls. Materials and Methods: Routine EEG records of 19 ASD patients and 19 matched controls were screened for IRDA/IRTA using a fully data driven analysis with fixed thresholds. IRDA/IRTA rates before and after hyperventilation (HV) as well as the HV-induced difference in IRDA/IRTA rates (HV difference) were analyzed. For inter-group measures, we used the Wilcoxon rank sum test. Results: Significantly increased HV difference was detected in the ASD group (p = 0.0497). However, the groups showed no difference in IRDA/IRTA rates before HV (p = 0.564) and after HV (p = 0.163). Conclusions: The lack of any group differences regarding IRDA/IRTA before HV might be related to the fact that we only studied non-secondary high-functioning autism in a small sample of epilepsy-free adult patients. A significantly increased HV difference might be regarded as a marker of subtle neuronal network instability possibly causing short-term disturbances via local area network inhibition and long-term effects via epileptic encephalopathy. PMID:28265243

  7. Coping food craving with neurofeedback. Evaluation of the usefulness of alpha/theta training in a non-clinical sample.

    PubMed

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

    2017-02-01

    The aim of the present study was to explore the usefulness of the alpha/theta (A/T) training in reducing Food Craving (FC) in a non-clinical sample. The modifications of electroencephalographic (EEG) power spectra associated with A/T training was also investigated. Fifty subjects were enrolled in the study and randomly assigned to receive ten sessions of A/T training [neurofeedback group (NFG)=25], or to act as controls [waiting list group (WLG)=25]. All participants were administered the Food Cravings Questionnaire-Trait, the Eating Disorder Examination Questionnaire and the Symptom Checklist-90-Revised. In the post training assessment, compared to the WLG, the NFG showed a significant reduction of intentions and plans to consume food (F1; 49=4.90; p=.033; d=0.626) and of craving as a physiological state (F1; 49=8.09; p=.007; d=803). In NFG, changes in FC persisted after 4months follow-up. Furthermore, A/T training was associated with significant a increase of resting EEG alpha power in several brain areas involved in FC (e.g., insula) and food cue reactivity (e.g., parahippocampal gyrus, inferior and superior temporal gyrus). Taken together, our results showed that ten sessions of A/T training are associated with a decrease of self-reported FC in a non-clinical sample. These findings suggest that this brain-directed intervention may be useful in the treatment of dysfunctional eating behaviors characterized by FC.

  8. Frontal midline theta rhythm and gamma power changes during focused attention on mental calculation: an MEG beamformer analysis.

    PubMed

    Ishii, Ryouhei; Canuet, Leonides; Ishihara, Tsutomu; Aoki, Yasunori; Ikeda, Shunichiro; Hata, Masahiro; Katsimichas, Themistoklis; Gunji, Atsuko; Takahashi, Hidetoshi; Nakahachi, Takayuki; Iwase, Masao; Takeda, Masatoshi

    2014-01-01

    Frontal midline theta rhythm (Fmθ) appears widely distributed over medial prefrontal areas in EEG recordings, indicating focused attention. Although mental calculation is often used as an attention-demanding task, little has been reported on calculation-related activation in Fmθ experiments. In this study we used spatially filtered MEG and permutation analysis to precisely localize cortical generators of the magnetic counterpart of Fmθ, as well as other sources of oscillatory activity associated with mental calculation processing (i.e., arithmetic subtraction). Our results confirmed and extended earlier EEG/MEG studies indicating that Fmθ during mental calculation is generated in the dorsal anterior cingulate and adjacent medial prefrontal cortex. Mental subtraction was also associated with gamma event-related synchronization, as an index of activation, in right parietal regions subserving basic numerical processing and number-based spatial attention. Gamma event-related desynchronization appeared in the right lateral prefrontal cortex, likely representing a mechanism to interrupt neural activity that can interfere with the ongoing cognitive task.

  9. Neural mechanisms of selective exposure: an EEG study on the processing of decision-consistent and inconsistent information.

    PubMed

    Fischer, Peter; Reinweber, Matthias; Vogrincic, Claudia; Schäfer, Axel; Schienle, Anne; Volberg, Gregor

    2013-01-01

    Decision makers tend to prefer decision-consistent information and/or neglect decision-inconsistent information (selective exposure). In the present EEG study the neural mechanisms of the classic selective exposure effect were examined by investigating oscillatory brain responses to consistent vs. inconsistent information. Twenty participants made an economic decision and subsequently were exposed to 45 consistent and 45 inconsistent images concerning their decision. EEG was recorded from 31 electrodes and differences between oscillatory brain responses towards consistent and inconsistent information were examined. The main result was an increase of induced theta power (5-8Hz, 0-0.7s) in the consistent compared to the inconsistent condition at right temporo-parietal electrodes, as well as a corresponding increase of evoked theta power at frontal electrodes. Since theta oscillations are often observed during memory formation, we conclude that decision-consistent information triggers memory formation, whereas decision-inconsistent information seems not to do so. This finding supports the classic motivational perspective of Leon Festinger on the selective exposure effect.

  10. EEG, temporal correlations, and avalanches.

    PubMed

    Benayoun, Marc; Kohrman, Michael; Cowan, Jack; van Drongelen, Wim

    2010-12-01

    Epileptiform activity in the EEG is frequently characterized by rhythmic, correlated patterns or synchronized bursts. Long-range temporal correlations (LRTC) are described by power law scaling of the autocorrelation function and have been observed in scalp and intracranial EEG recordings. Synchronous large-amplitude bursts (also called neuronal avalanches) have been observed in local field potentials both in vitro and in vivo. This article explores the presence of neuronal avalanches in scalp and intracranial EEG in the context of LRTC. Results indicate that both scalp and intracranial EEG show LRTC, with larger scaling exponents in scalp recordings than intracranial. A subset of analyzed recordings also show avalanche behavior, indicating that avalanches may be associated with LRTC. Artificial test signals reveal a linear relationship between the scaling exponent measured by detrended fluctuation analysis and the exponent of the avalanche size distribution. Analysis and evaluation of simulated data reveal that preprocessing of EEG (squaring the signal or applying a filter) affect the ability of detrended fluctuation analysis to reliably measure LRTC.

  11. Inter-individual and intra-individual variation of the effects of pulsed RF EMF exposure on the human sleep EEG.

    PubMed

    Lustenberger, Caroline; Murbach, Manuel; Tüshaus, Laura; Wehrle, Flavia; Kuster, Niels; Achermann, Peter; Huber, Reto

    2015-04-01

    Pulse-modulated radiofrequency electromagnetic fields (RF EMF) can alter brain activity during sleep; increases of electroencephalographic (EEG) power in the sleep spindle (13.75-15.25 Hz) and delta-theta (1.25-9 Hz) frequency range have been reported. These field effects show striking inter-individual differences. However, it is still unknown whether individual subjects react in a similar way when repeatedly exposed. Thus, our study aimed to investigate inter-individual variation and intra-individual stability of field effects. To do so, we exposed 20 young male subjects twice for 30 min prior to sleep to the same amplitude modulated 900 MHz (2 Hz pulse, 20 Hz Gaussian low-pass filter and a ratio of peak-to-average of 4) RF EMF (spatial peak absorption of 2 W/kg averaged over 10 g) 2 weeks apart. The topographical analysis of EEG power during all-night non-rapid eye movement sleep revealed: (1) exposure-related increases in delta-theta frequency range in several fronto-central electrodes; and (2) no differences in spindle frequency range. We did not observe reproducible within-subject RF EMF effects on sleep spindle and delta-theta activity in the sleep EEG and it remains unclear whether a biological trait of how the subjects' brains react to RF EMF exists.

  12. Cerebellar Intermittent Theta-Burst Stimulation and Motor Control Training in Individuals with Cervical Dystonia

    PubMed Central

    Bradnam, Lynley V.; McDonnell, Michelle N.; Ridding, Michael C.

    2016-01-01

    Background: There is emerging evidence that cervical dystonia is a neural network disorder with the cerebellum as a key node. The cerebellum may provide a target for neuromodulation as a therapeutic intervention in cervical dystonia. Objective: This study aimed to assess effects of intermittent theta-burst stimulation of the cerebellum on dystonia symptoms, quality of life, hand motor dexterity and cortical neurophysiology using transcranial magnetic stimulation. Methods: Sixteen participants with cervical dystonia were randomised into real or sham stimulation groups. Cerebellar neuromodulation was combined with motor training for the neck and an implicit learning task. The intervention was delivered over 10 working days. Outcome measures included dystonia severity and pain, quality of life, hand dexterity, and motor-evoked potentials and cortical silent periods recorded from upper trapezius muscles. Assessments were taken at baseline and after 5 and 10 days, with quality of life also measured 4 and 12 weeks later. Results: Intermittent theta-burst stimulation improved dystonia severity (Day 5, −5.44 points; p = 0.012; Day 10, −4.6 points; p = 0.025), however, effect sizes were small. Quality of life also improved (Day 5, −10.6 points, p = 0.012; Day 10, −8.6 points, p = 0.036; Week 4, −12.5 points, p = 0.036; Week 12, −12.4 points, p = 0.025), with medium or large effect sizes. There was a reduction in time to complete the pegboard task pre to post intervention (both p < 0.008). Cortical neurophysiology was unchanged by cerebellar neuromodulation. Conclusion: Intermittent theta-burst stimulation of the cerebellum may improve cervical dystonia symptoms, upper limb motor control and quality of life. The mechanism likely involves promoting neuroplasticity in the cerebellum although the neurophysiology remains to be elucidated. Cerebellar neuromodulation may have potential as a novel treatment intervention for cervical dystonia, although larger

  13. A Low energy neutrino factory for large theta(13)

    SciTech Connect

    Geer, Steve; Mena, Olga; Pascoli, Silvia; /Durham U., IPPP

    2007-01-01

    If the value of {theta}{sub 13} is within the reach of the upcoming generation of long-baseline experiments, T2K and NOvA, they show that a low-energy neutrino factory, with peak energy in the few GeV range, would provide a sensitive tool to explore CP-violation and the neutrino mass hierarchy. They consider baselines with typical length 1000-1500 km. The unique performance of the low energy neutrino factory is due to the rich neutrino oscillation pattern at energies between 1 and 4 GeV at baselines {Omicron}(1000) km. They perform both a semi-analytical study of the sensitivities and a numerical analysis to explore how well this setup can measure {theta}{sub 13}, CP-violation, and determine the type of mass hierarchy and the {theta}{sub 23} quadrant. A low energy neutrino factory provides a powerful tool to resolve ambiguities and make precise parameter determinations, for both large and fairly small values of the mixing parameter {theta}{sub 13}.

  14. Classical Conditioning of Hippocampal Theta Patterns in the Rat.

    DTIC Science & Technology

    1976-08-01

    associated with changes in performance of learned tasks , 1,4,5, 8,9 there have been very few studies of neurona l plasticity of the hippocampus It self...rapid development of a conditioned hippocampal theta response to a visual sti mulus demonstrates tha t there is considerable neurona l plasticity in the

  15. Presence of state transitions in the cryptophyte alga Guillardia theta.

    PubMed

    Cheregi, Otilia; Kotabová, Eva; Prášil, Ondřej; Schröder, Wolfgang P; Kaňa, Radek; Funk, Christiane

    2015-10-01

    Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing antennae excitation between the photosystems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mechanisms have been analysed in the cryptophyte alga Guillardia theta. Photoprotective non-photochemical quenching was observed in cultures only after they had entered the stationary growth phase. These cells displayed a diminished overall photosynthetic efficiency, measured as CO2 assimilation rate and electron transport rate. However, in the logarithmic growth phase G. theta cells redistributed excitation energy via a mechanism similar to state transitions. These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective. It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively. G. theta therefore represents a chromalveolate algae able to perform state transitions.

  16. Predictability of EEG interictal spikes.

    PubMed Central

    Scott, D A; Schiff, S J

    1995-01-01

    To determine whether EEG spikes are predictable, time series of EEG spike intervals were generated from subdural and depth electrode recordings from four patients. The intervals between EEG spikes were hand edited to ensure high accuracy and eliminate false positive and negative spikes. Spike rates (per minute) were generated from longer time series, but for these data hand editing was usually not feasible. Linear and nonlinear models were fit to both types of data. One patient had no linear or nonlinear predictability, two had predictability that could be well accounted for with a linear stochastic model, and one had a degree of nonlinear predictability for both interval and rate data that no linear model could adequately account for. PMID:8580318

  17. EEG signal analysis: a survey.

    PubMed

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

    2010-04-01

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

  18. Complex dynamics of epileptic EEG.

    PubMed

    Kannathal, N; Puthusserypady, Sadasivan K; Choo Min, Lim

    2004-01-01

    Electroencephalogram (EEG) - the recorded representation of electrical activity of the brain contain useful information about the state of the brain. Recent studies indicate that nonlinear methods can extract valuable information from neuronal dynamics. We compare the dynamical properties of EEG signals of healthy subjects with epileptic subjects using nonlinear time series analysis techniques. Chaotic invariants like correlation dimension (D2) , largest Lyapunov exponent (lambda1), Hurst exponent (H) and Kolmogorov entropy (K) are used to characterize the signal. Our study showed clear differences in dynamical properties of brain electrical activity of the normal and epileptic subjects with a confidence level of more than 90%. Furthermore to support this claim fractal dimension (FD) analysis is performed. The results indicate reduction in value of FD for epileptic EEG indicating reduction in system complexity.

  19. Engagement Assessment Using EEG Signals

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  20. 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.

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

    PubMed

    Nishifuji, Seiji

    2011-01-01

    The present paper investigated response of electroencephalogram (EEG) to aerobic exercise with low intensity after performing mental task with listening to acoustic stimuli in order to measure a recovery effect of the acute exercise on the EEG. The mean amplitude of the alpha wave (8-13 Hz) was significantly reduced during performing mental arithmetic and/or listening to 5 KHz unpleasant tone. In particular, the mean reduction rate of the amplitude was more than 20 % in the low-frequency range of the alpha wave (8-10 Hz) under both stressors. On the other hand, the alpha wave was fixed after an acute exercise of 20 min; the mean amplitude of the alpha wave exceeded 30 % of spontaneous level prior to stressed conditions in the low-frequency range but unchanged in the high-frequency range. Response of the theta wave was similar to the low-alpha wave, while beta and gamma waves showed no significant change in response to the stressors and exercise. The observation indicates that the acute exercise with low intensity may be responsible for the rapid recovery and enhancement of the alpha wave in the low-frequency range and theta wave.

  2. Relation between Resting State Front-Parietal EEG Coherence and Executive Function in Parkinson's Disease

    PubMed Central

    Teramoto, Hiroko; Akimoto, Takayoshi; Shiota, Hiroshi; Kamei, Satoshi

    2016-01-01

    Objective. To assess the relation between executive dysfunction (ED) in Parkinson's disease (PD) and resting state functional connectivity evaluated using electroencephalography (EEG) coherence. Methods. Sixty-eight nondemented sporadic PD patients were assessed using the Behavioural Assessment of the Dysexecutive Syndrome (BADS) to evaluate executive function. EEG coherence in the left frontoparietal electrode pair (F3-P3) and the right frontoparietal electrode pair (F4-P4) was analyzed in the alpha and theta range. The BADS scores were compared across the coherence groups, and the multiple logistic regression analysis was performed to assess the contribution of confounders. Results. The standardized BADS score was significantly lower in the low F3-P3 coherence group in the alpha range (Mann-Whitney U test, p = 0.032), though there was no difference between F4-P4 coherence group in the alpha range, F3-P3, and F4-P4 coherence groups in the theta range and the standardized BADS score. The multiple logistic regression analysis revealed the significant relation between the F3-P3 coherence group in alpha range and age-controlled standardized BADS score (p = 0.039, 95% CI = 1.002–1.062). Conclusion. The decrease in resting state functional connectivity between the frontal and parietal cortices especially in the left side is related to ED in PD. PMID:27433473

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

    PubMed

    Baumeister, J; von Detten, S; van Niekerk, S-M; Schubert, M; Ageberg, E; Louw, Q A

    2013-12-01

    Landing from a jump is related to predictive sensorimotor control. Frontal, central and parietal brain areas are known to play a role in this process based on online sensory feedback. This can be measured by EEG. However, there is only limited knowledge about brain activity during predictive preparation for drop landings (DL). The purpose is to demonstrate changes in brain activity in preparation for DL in different conditions. After resting, 10 athletes performed a series of DLs and were asked to concentrate on the landing preparation for 10 s before an auditory signal required them to drop land from a 30 cm platform. This task was executed before and after a standardized fatigue protocol. EEG spectral power was calculated during DL preparation. Frontal Theta power was increased during preparation compared to rest. Parietal Alpha-2 power demonstrated higher values in preparation after fatigue condition while lower limb kinematics remained unchanged. Cortical activity in frontal and parietal brain areas is sensitive for predictive sensorimotor control of drop landings. Frontal Theta power demonstrates an increase and is related to higher attentional control. In a fatigued condition the parietal Alpha-2 power increase might be related to a deactivation in the somatosensory brain areas.

  4. 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.

  5. [The impact of experimental instruction on changes in EEG power during verbal creative thinking in men and women].

    PubMed

    Tarasova, I V; Razumnikova, O M; Vol'f, N V

    2006-01-01

    Features of EEG pattern during verbal creative thinking depending on experimental instruction were studied in men and women. Spectral power density was analyzed in six frequency bands (4-30 Hz). Performance of a creative task produced an increase in the power of theta (4-6 Hz) and beta2 (20-40 Hz) components and decrease in the power of alpha (8-13 Hz) and betal (13-20 Hz). Changes in the alpha and betal bands were observed, predominantly, in the posterior areas, whereas power of the thetal and beta2 bands increased in the anterior areas. Independently of instruction, women demonstrated greater synchronization in the theta1 band than men, whereas in men the desynchronization in the alpha2 band (10-13 Hz) was more pronounced. When the subjects were instructed to create original sentences, a widespread decrease in the EEG power was observed in the band of 8-30 Hz as compared to instruction "to create sentences". Thus, the instruction-related changes in EEG power were not gender-specific. They may reflect neural activity mediating selective attention.

  6. Subject position affects EEG magnitudes.

    PubMed

    Rice, Justin K; Rorden, Christopher; Little, Jessica S; Parra, Lucas C

    2013-01-01

    EEG (electroencephalography) has been used for decades in thousands of research studies and is today a routine clinical tool despite the small magnitude of measured scalp potentials. It is widely accepted that the currents originating in the brain are strongly influenced by the high resistivity of skull bone, but it is less well known that the thin layer of CSF (cerebrospinal fluid) has perhaps an even more important effect on EEG scalp magnitude by spatially blurring the signals. Here it is shown that brain shift and the resulting small changes in CSF layer thickness, induced by changing the subject's position, have a significant effect on EEG signal magnitudes in several standard visual paradigms. For spatially incoherent high-frequency activity the effect produced by switching from prone to supine can be dramatic, increasing occipital signal power by several times for some subjects (on average 80%). MRI measurements showed that the occipital CSF layer between the brain and skull decreases by approximately 30% in thickness when a subject moves from prone to supine position. A multiple dipole model demonstrated that this can indeed lead to occipital EEG signal power increases in the same direction and order of magnitude as those observed here. These results suggest that future EEG studies should control for subjects' posture, and that some studies may consider placing their subjects into the most favorable position for the experiment. These findings also imply that special consideration should be given to EEG measurements from subjects with brain atrophy due to normal aging or neurodegenerative diseases, since the resulting increase in CSF layer thickness could profoundly decrease scalp potential measurements.

  7. Integration of an EEG biomarker with a clinician's ADHD evaluation

    PubMed Central

    Snyder, Steven M; Rugino, Thomas A; Hornig, Mady; Stein, Mark A

    2015-01-01

    Background This study is the first to evaluate an assessment aid for attention-deficit/hyperactivity disorder (ADHD) according to both Class-I evidence standards of American Academy of Neurology and De Novo requirements of US Food and Drug Administration. The assessment aid involves a method to integrate an electroencephalographic (EEG) biomarker, theta/beta ratio (TBR), with a clinician's ADHD evaluation. The integration method is intended as a step to help improve certainty with criterion E (i.e., whether symptoms are better explained by another condition). Methods To evaluate the assessment aid, investigators conducted a prospective, triple-blinded, 13-site, clinical cohort study. Comprehensive clinical evaluation data were obtained from 275 children and adolescents presenting with attentional and behavioral concerns. A qualified clinician at each site performed differential diagnosis. EEG was collected by separate teams. The reference standard was consensus diagnosis by an independent, multidisciplinary team (psychiatrist, psychologist, and neurodevelopmental pediatrician), which is well-suited to evaluate criterion E in a complex clinical population. Results Of 209 patients meeting ADHD criteria per a site clinician's judgment, 93 were separately found by the multidisciplinary team to be less likely to meet criterion E, implying possible overdiagnosis by clinicians in 34% of the total clinical sample (93/275). Of those 93, 91% were also identified by EEG, showing a relatively lower TBR (85/93). Further, the integration method was in 97% agreement with the multidisciplinary team in the resolution of a clinician's uncertain cases (35/36). TBR showed statistical power specific to supporting certainty of criterion E per the multidisciplinary team (Cohen's d, 1.53). Patients with relatively lower TBR were more likely to have other conditions that could affect criterion E certainty (10 significant results; P ≤ 0.05). Integration of this information with a

  8. The separate and combined effects of monoamine oxidase A inhibition and nicotine on resting state EEG.

    PubMed

    Smith, Dylan M; Fisher, Derek; Blier, Pierre; Ilivitsky, Vadim; Knott, Verner

    2016-01-01

    While nicotine is often associated with the neuropsychological effects of tobacco smoke, the robust monoamine oxidase (MAO) inhibition observed in chronic smokers is also likely to play a role. Electroencephalographically-indexed alterations in baseline neural oscillations by nicotine have previously been reported in both smokers and non-smokers, however, little is known about the effects of MAO inhibition in combination with nicotine on resting state EEG. In a sample of 24 healthy non-smoking males, the effects of 6 mg nicotine gum, as well as MAO-A inhibition via 75 mg moclobemide, were investigated in separate and combined conditions over four separate test sessions. Drug effects were observed in the alpha2, beta2, and theta band frequencies. Nicotine increased alpha2 power, and moclobemide decreased beta2 power. Theta power was decreased most robustly by the combination of both drugs. Therefore, this study demonstrated that the nicotinic and MAO inhibiting properties of tobacco may differentially influence fast-wave oscillations (alpha2 and beta2), while acting in synergy to influence theta oscillations.

  9. Spatial organization of EEG coherence during listening to consonant and dissonant chords.

    PubMed

    Passynkova, Natalia; Neubauer, Heinrich; Scheich, Henning

    2007-01-22

    Theories of harmony state that the contribution of both sensory and cognitive components is important for musical consonance perception. The aims of the present study were to analyze (a) functional intra- and inter-hemispheric connectivity associated with listening to consonant and dissonant chords using EEG coherence method; (b) relationships between affective responsiveness, sensory aspects of perceived consonance and associated brain connectivity. We identified two lines of inter-hemispheric connectivity in the theta band; one localized anterior being sensitive to consonance and one localized posterior sensitive to dissonance. Stronger right intra-hemispheric connectivity for consonance than dissonance in the theta band was associated with higher pleasantness ratings. The relationship between sensory aspects of perceived consonance and left intra-hemispheric connectivity found in theta-2 was interpreted as processing of vertical harmony without emotional involvement. The stronger connectivity along the axis "left anterior-right posterior" for dissonance than consonance in the alpha-1 band is discussed as a correlate of novelty processing. By introducing a "auditory object dissociation" hypothesis we suggest to extend the present concept of harmony perception. We believe that "auditory object dissociation" is a component of "sensory dissonance."

  10. Effects of working memory load on oscillatory power in human intracranial EEG.

    PubMed

    Meltzer, Jed A; Zaveri, Hitten P; Goncharova, Irina I; Distasio, Marcello M; Papademetris, Xenophon; Spencer, Susan S; Spencer, Dennis D; Constable, R Todd

    2008-08-01

    Studies of working memory load effects on human EEG power have indicated divergent effects in different frequency bands. Although gamma power typically increases with load, the load dependency of the lower frequency theta and alpha bands is uncertain. We obtained intracranial electroencephalography measurements from 1453 electrode sites in 14 epilepsy patients performing a Sternberg task, in order to characterize the anatomical distribution of load-related changes across the frequency spectrum. Gamma power increases occurred throughout the brain, but were most common in the occipital lobe. In the theta and alpha bands, both increases and decreases were observed, but with different anatomical distributions. Increases in theta and alpha power were most prevalent in frontal midline cortex. Decreases were most commonly observed in occipital cortex, colocalized with increases in the gamma range, but were also detected in lateral frontal and parietal regions. Spatial overlap with group functional magnetic resonance imaging results was minimal except in the precentral gyrus. These findings suggest that power in any given frequency band is not a unitary phenomenon; rather, reactivity in the same frequency band varies in different brain regions, and may relate to the engagement or inhibition of a given area in a cognitive task.

  11. EEG source reconstruction reveals frontal-parietal dynamics of spatial conflict processing.

    PubMed

    Cohen, Michael X; Ridderinkhof, K Richard

    2013-01-01

    Cognitive control requires the suppression of distracting information in order to focus on task-relevant information. We applied EEG source reconstruction via time-frequency linear constrained minimum variance beamforming to help elucidate the neural mechanisms involved in spatial conflict processing. Human subjects performed a Simon task, in which conflict was induced by incongruence between spatial location and response hand. We found an early (∼200 ms post-stimulus) conflict modulation in stimulus-contralateral parietal gamma (30-50 Hz), followed by a later alpha-band (8-12 Hz) conflict modulation, suggesting an early detection of spatial conflict and inhibition of spatial location processing. Inter-regional connectivity analyses assessed via cross-frequency coupling of theta (4-8 Hz), alpha, and gamma power revealed conflict-induced shifts in cortical network interactions: Congruent trials (relative to incongruent trials) had stronger coupling between frontal theta and stimulus-contrahemifield parietal alpha/gamma power, whereas incongruent trials had increased theta coupling between medial frontal and lateral frontal regions. These findings shed new light into the large-scale network dynamics of spatial conflict processing, and how those networks are shaped by oscillatory interactions.

  12. Appetitive long-term taste conditioning enhances human visually evoked EEG responses.

    PubMed

    Viemose, Ida; Møller, Per; Laugesen, Jakob L; Schachtman, Todd R; Manoharan, Thukirtha; Christoffersen, Gert R J

    2013-09-15

    Long-term effects of learned associations between an image and a taste have not been studied with electromagnetic brain scanning techniques. The possibility that taste conditioning may change sensory image processing was investigated in young adult subjects. EEG-responses evoked by images were recorded before and after a training session using an image as conditioned stimulus and a pleasant taste as unconditioned stimulus. The results showed that in posterior electrodes placed over visual cortex areas, the following changes occurred after conditioning: (1) the amplitude and duration of the N2-P3 waves in the visual evoked potentials were enhanced; (2) the N2 and P3 peak delays were shortened; (3) power induced by image presentation was enhanced in the delta and theta frequency bands; (4) cross-hemispheric delta and theta coherences among the posterior electrodes were enhanced; (5) calculations of the underlying whole brain distribution of currents using swLORETA showed elevated current densities in posterior voxels. None of the above changes occurred in a sham-trained control group. In electrodes placed over the prefrontal cortex, delta and theta power also rose significantly. It is suggested that the appetitive taste conditioning potentiated synaptic activity in visual cortex networks and that this led to an increased speed of image processing.

  13. EEG connectivity between the subgenual anterior cingulate and prefrontal cortices in response to antidepressant medication.

    PubMed

    Iseger, Tabitha A; Korgaonkar, Mayuresh S; Kenemans, J Leon; Grieve, Stuart M; Baeken, Chris; Fitzgerald, Paul B; Arns, Martijn

    2017-02-22

    Antidepressant medication is the most common treatment for major depressive disorder (MDD), however, the precise working mechanism underlying these treatments remains unclear. Recent neuromodulation treatments demonstrate that direct stimulation of the dorsolateral prefrontal cortex (DLPFC), dorsomedial prefrontal cortex (DMPFC), and subgenual anterior cingulate (sgACC) relate to clinical improvement, suggesting connectivity alterations of the DLPFC-DMPFC-sgACC network to mediate antidepressant response. The international Study to Predict Optimized Treatment in Depression (iSPOT-D) is an international multicentre study that collected EEG data for 1008 MDD patients, randomized to 3 different antidepressant medications (N=447 MDD with complete pre- and post-treatment data and N=336 non-MDD). Treatment response was defined by a decline of >50% on the Hamilton Rating Score for Depression (HRSD17). We investigated whether connectivity in alpha and theta frequencies of the DLPFC-DMPFC-sgACC network changed from pre- to post-treatment between: (i) patients and controls, and (ii) responders (R) and non-responders (NR). Women exhibited higher alpha and theta connectivity compared to males, both pre- and post-treatment. Furthermore, theta, but not alpha, hypo-connectivity was found for MDD patients. A decreased alpha connectivity after treatment was found only for male responders, while non-responders and females exhibited no changes in alpha connectivity. Decreasing alpha connectivity could potentially serve as a treatment emergent biomarker, in males only. Furthermore, it could be useful to a priori stratify by gender for future MDD studies.

  14. Depression-Related Brain Connectivity Analyzed by EEG Event-Related Phase Synchrony Measure

    PubMed Central

    Li, Yuezhi; Kang, Cheng; Qu, Xingda; Zhou, Yunfei; Wang, Wuyi; Hu, Yong

    2016-01-01

    This study is to examine changes of functional connectivity in patients with depressive disorder using synchronous brain activity. Event-related potentials (ERPs) were acquired during a visual oddball task in 14 patients with depressive disorder and 19 healthy controls. Electroencephalogram (EEG) recordings were analyzed using event-related phase coherence (ERPCOH) to obtain the functional network. Alteration of the phase synchronization index (PSI) of the functional network was investigated. Patients with depression showed a decreased number of significant electrode pairs in delta phase synchronization, and an increased number of significant electrode pairs in theta, alpha and beta phase synchronization, compared with controls. Patients with depression showed lower target-dependent PSI increment in the frontal-parietal/temporal/occipital electrode pairs in delta-phase synchronization than healthy participants. However, patients with depression showed higher target-dependent PSI increments in theta band in the prefrontal/frontal and frontal-temporal electrode pairs, higher PSI increments in alpha band in the prefrontal pairs and higher increments of beta PSI in the central and right frontal-parietal pairs than controls. It implied that the decrease in delta PSI activity in major depression may indicate impairment of the connection between the frontal and parietal/temporal/occipital regions. The increase in theta, alpha and beta PSI in the frontal/prefrontal sites might reflect the compensatory mechanism to maintain normal cognitive performance. These findings may provide a foundation for a new approach to evaluate the effectiveness of therapeutic strategies for depression. PMID:27725797

  15. Modulation of Hippocampal Theta Oscillations and Spatial Memory by Relaxin-3 Neurons of the Nucleus Incertus

    ERIC Educational Resources Information Center

    Ma, Sherie; Olucha-Bordonau, Francisco E.; Hossain, M. Akhter; Lin, Feng; Kuei, Chester; Liu, Changlu; Wade, John D.; Sutton, Steven W.; Nunez, Angel; Gundlach, Andrew L.

    2009-01-01

    Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that "pacemaker" neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the…

  16. EEG Oscillation Evidences of Enhanced Susceptibility to Emotional Stimuli during Adolescence

    PubMed Central

    Meng, Xianxin; Liu, Wenwen; Zhang, Ling; Li, Xiang; Yao, Bo; Ding, Xinsheng; Yuan, JiaJin; Yang, Jiemin

    2016-01-01

    Background: Our recent event-related potential (ERP) study showed that adolescents are more emotionally sensitive to negative events compared to adults, regardless of the valence strength of the events. The current work aimed to confirm this age-related difference in response to emotional stimuli of diverse intensities by examining Electroencephalography (EEG) oscillatory power in time-frequency analysis. Methods: Time-frequency analyses were performed on the EEG data recorded for highly negative (HN), moderately negative (MN) and Neutral pictures in 20 adolescents and 20 adults during a covert emotional task. The results showed a significant age by emotion interaction effect in the theta and beta oscillatory power during the 500–600 ms post stimulus. Results: Adolescents showed significantly less pronounced theta synchronization (ERS, 5.5–7.5 Hz) for HN stimuli, and larger beta desynchronization (ERD; 18–20 Hz) for both HN and MN stimuli, in comparison with neutral stimuli. By contrast, adults exhibited no significant emotion effects in theta and beta frequency bands. In addition, the analysis of the alpha spectral power (10.5–12 Hz; 850–950 ms) showed a main effect of emotion, while the emotion by age interaction was not significant. Irrespective of adolescents or adults, HN and MN stimuli elicited enhanced alpha suppression compared to Neutral stimuli, while the alpha power was similar across HN and MN conditions. Conclusions: These results confirmed prior findings that adolescents are more sensitive to emotionally negative stimuli compared to adults, regardless of emotion intensity, possibly due to the developing prefrontal control system during adolescence. PMID:27242568

  17. Possible EEG sequelae of very long duration marihuana use: pilot findings from topographic quantitative EEG analyses of subjects with 15 to 24 years of cumulative daily exposure to THC.

    PubMed

    Struve, F A; Patrick, G; Straumanis, J J; Fitz-Gerald, M J; Manno, J

    1998-01-01

    In previous work we demonstrated and replicated a significant association between increased absolute and relative power and interhemispheric coherence of EEG alpha activity over the bilateral frontal-central cortex ("alpha hyperfrontality") in daily marihuana users as contrasted with nonusers. In this report we focused our analyses on subjects who reported smoking marihuana on a daily basis for 15 to 24 consecutive years. Compared to nonuser controls and subjects who had used marihuana on a daily basis for shorter periods of time, subjects with excessively long cumulative exposures to THC were found to have significantly elevated absolute power of theta activity over bilateral frontal-central cortex, as well as significantly increased interhemispheric coherence of theta activity across central and posterior regions. Concurrent reaction time studies conducted in our laboratory suggest that very long duration cumulative marihuana exposure might be associated with slowed cognitive processing.

  18. Nonlinear dynamics and quantitative EEG analysis.

    PubMed

    Jansen, B H

    1996-01-01

    Quantitative, computerized electroencephalogram (EEG) analysis appears to be based on a phenomenological approach to EEG interpretation, and is primarily rooted in linear systems theory. A fundamentally different approach to computerized EEG analysis, however, is making its way into the laboratories. The basic idea, inspired by recent advances in the area of nonlinear dynamics and chaos theory, is to view an EEG as the output of a deterministic system of relatively simple complexity, but containing nonlinearities. This suggests that studying the geometrical dynamics of EEGs, and the development of neurophysiologically realistic models of EEG generation may produce more successful automated EEG analysis techniques than the classical, stochastic methods. A review of the fundamentals of chaos theory is provided. Evidence supporting the nonlinear dynamics paradigm to EEG interpretation is presented, and the kind of new information that can be extracted from the EEG is discussed. A case is made that a nonlinear dynamic systems viewpoint to EEG generation will profoundly affect the way EEG interpretation is currently done.

  19. Odds Ratio Product of Sleep EEG as a Continuous Measure of Sleep State

    PubMed Central

    Younes, Magdy; Ostrowski, Michele; Soiferman, Marc; Younes, Henry; Younes, Mark; Raneri, Jill; Hanly, Patrick

    2015-01-01

    Study Objectives: To develop and validate an algorithm that provides a continuous estimate of sleep depth from the electroencephalogram (EEG). Design: Retrospective analysis of polysomnograms. Setting: Research laboratory. Participants: 114 patients who underwent clinical polysomnography in sleep centers at the University of Manitoba (n = 58) and the University of Calgary (n = 56). Interventions: None. Measurements and Results: Power spectrum of EEG was determined in 3-second epochs and divided into delta, theta, alpha-sigma, and beta frequency bands. The range of powers in each band was divided into 10 aliquots. EEG patterns were assigned a 4-digit number that reflects the relative power in the 4 frequency ranges (10,000 possible patterns). Probability of each pattern occurring in 30-s epochs staged awake was determined, resulting in a continuous probability value from 0% to 100%. This was divided by 40 (% of epochs staged awake) producing the odds ratio product (ORP), with a range of 0–2.5. In validation testing, average ORP decreased progressively as EEG progressed from wakefulness (2.19 ± 0.29) to stage N3 (0.13 ± 0.05). ORP < 1.0 predicted sleep and ORP > 2.0 predicted wakefulness in > 95% of 30-s epochs. Epochs with intermediate ORP occurred in unstable sleep with a high arousal index (> 70/h) and were subject to much interrater scoring variability. There was an excellent correlation (r2 = 0.98) between ORP in current 30-s epochs and the likelihood of arousal or awakening occurring in the next 30-s epoch. Conclusions: Our results support the use of the odds ratio product (ORP) as a continuous measure of sleep depth. Citation: Younes M, Ostrowski M, Soiferman M, Younes H, Younes M, Raneri J, Hanly P. Odds ratio product of sleep EEG as a continuous measure of sleep state. SLEEP 2015;38(4):641–654. PMID:25348125

  20. [EEG spectral characteristics at different stages of the unconscious visual set in two motivation conditions].

    PubMed

    Kurova, N S; Cheremushkin, E A; Ashkinazi, M L

    2002-01-01

    Multichannel EEG were recorded in young healthy subjects in two series of experiments during formation, actualization, and extinction of the visual unconscious set to the perception of unequal circles under conditions of increased motivation of subjects to the result of their performance. In the first series of experiments, subjects were promised to be rewarded (a small money price) for each correct response (the "general" rise of motivation). In the second series, subjects were promised to be rewarded for correct responses only in cases when one of the circles was larger than the other one (the "directed" rise of motivation). The dynamics of the EEG spectral power derived under these two conditions was compared with similar indices obtained earlier during formation of the same set without any special motivation of subjects (control). In all experimental conditions, before the presentation of the stimuli the EEG power in the alpha range was higher in subjects with the stable set. The dynamics of changes in the alpha power at set stages was principally similar in all conditions. In all the experimental conditions, in subjects with unstable set the EEG power in the delta range was highest at the stage of set actualization. The most pronounced generalized changes in the EEG power in the theta-range during the "general" rise of motivation in subjects with stable and unstable forms of set and greater variability of the reaction time to the probe stimulus suggest that the task performance under these conditions required greater tension than under conditions of the "directed" rise of motivation.

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

    PubMed

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

    2014-07-01

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

  2. Stroboscopic artifact in digital video-EEG.

    PubMed

    Quigg, Mark; Taft, William

    2004-01-01

    Combined digital video-EEG (DV-EEG) systems eliminate many familiar technical artifacts of older analog recorders; however, new and unanticipated technical issues are becoming evident. In this report, a case is described that identifies one of these technical limitations that could represent a pitfall to accurate data interpretation. An EEG was recorded on an 18-year-old man with history of photically sensitive generalized tonic-clonic seizures, revealing photoparoxysmal responses that appeared to outlast photic stimulation. However, in an attempted video-EEG correlation, the digital video recording showed variable appearance or absence of photic bursts that did not correlate with EEG photic tick marks, initially suggesting desynchronization between video and EEG signals. However, the absence of flashes seen on the video record resulted from stroboscopic artifact caused by mismatch between strobe frequency, video sampling rate, and video display characteristics. Stroboscopic aliasing is a DV-EEG specific artifact that can complicate accurate interpretation of photoparoxysmal responses.

  3. EEG Alpha Power and Intelligence.

    ERIC Educational Resources Information Center

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

    2002-01-01

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

  4. [Topographic-quantitative EEG-analysis of the paradoxical arousal reaction. EEG changes during urologic surgery using isoflurane/ N2O anesthesia].

    PubMed

    Bischoff, P; Kochs, E; Droese, D; Meyer-Moldenhauer, W H; Schulte am Esch, J

    1993-03-01

    arousal patterns were seen in these patients. In group 2, delta output changed from 69.6 microV2/Hz (baseline) to 147.4 microV2/Hz at frontal leads (F4) 5-6 min after the start of surgery. Only minimal changes were observed for theta activity. At the same time, in most cases fast wave activity (alpha 1, alpha 2, beta 1 and beta 2) was decreased by more than 50% at identical cortical areas. Increases in MAP were noted continuously after start of surgery up to a maximum of 19.8% from baseline, which became significant at the 16-min level. Heart rate did not change over time. DISCUSSION. Our data demonstrate that EEG slowing may be induced by surgical stimulation during steady-state anaesthesia with 0.6% isoflurane/66% nitrous oxide in oxygen. These findings are consistent with previous reports indicating the occurrence of slow wave patterns following sensory stimulation in comatose patients. Since these events occur predominantly at frontal areas they may not be detected with single-channel parietal recordings. Our data suggest that topographical EEG monitoring may useful for assessing painful events during surgery. Using EEG monoparameters like spectral edge frequency or median the occurrence of paradoxical arousal reactions may be falsely interpreted as an increased depth of anaesthesia.

  5. Increased EEG sigma and beta power during NREM sleep in primary insomnia.

    PubMed

    Spiegelhalder, Kai; Regen, Wolfram; Feige, Bernd; Holz, Johannes; Piosczyk, Hannah; Baglioni, Chiara; Riemann, Dieter; Nissen, Christoph

    2012-12-01

    The hyperarousal model of primary insomnia suggests that a deficit of attenuating arousal during sleep might cause the experience of non-restorative sleep. In the current study, we examined EEG spectral power values for standard frequency bands as indices of cortical arousal and sleep protecting mechanisms during sleep in 25 patients with primary insomnia and 29 good sleeper controls. Patients with primary insomnia demonstrated significantly elevated spectral power values in the EEG beta and sigma frequency band during NREM stage 2 sleep. No differences were observed in other frequency bands or during REM sleep. Based on prior studies suggesting that EEG beta activity represents a marker of cortical arousal and EEG sleep spindle (sigma) activity is an index of sleep protective mechanisms, our findings may provide further evidence for the concept that a simultaneous activation of wake-promoting and sleep-protecting neural activity patterns contributes to the experience of non-restorative sleep in primary insomnia.

  6. Interactive effects of age and gender on EEG power and coherence during a short-term memory task in middle-aged adults.

    PubMed

    Kober, Silvia Erika; Reichert, Johanna Louise; Neuper, Christa; Wood, Guilherme

    2016-04-01

    The effects of age and gender on electroencephalographic (EEG) activity during a short-term memory task were assessed in a group of 40 healthy participants aged 22-63 years. Multi-channel EEG was recorded in 20 younger (mean = 24.65-year-old, 10 male) and 20 middle-aged participants (mean = 46.40-year-old, 10 male) during performance of a Sternberg task. EEG power and coherence measures were analyzed in different frequency bands. Significant interactions emerged between age and gender in memory performance and concomitant EEG parameters, suggesting that the aging process differentially influences men and women. Middle-aged women showed a lower short-term memory performance compared to young women, which was accompanied by decreasing delta and theta power and increasing brain connectivity with age in women. In contrast, men showed no age-related decline in short-term memory performance and no changes in EEG parameters. These results provide first evidence of age-related alterations in EEG activity underlying memory processes, which were already evident in the middle years of life in women but not in men.

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

    PubMed

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

    2014-01-01

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

  8. EEG evidence of face-specific visual self-representation.

    PubMed

    Miyakoshi, Makoto; Kanayama, Noriaki; Iidaka, Tetsuya; Ohira, Hideki

    2010-05-01

    Cognitive science has regarded an individual's face as a form of representative stimuli to engage self-representation. The domain-generality of self-representation has been assumed in several reports, but was recently refuted in a functional magnetic resonance imaging study (Sugiura et al., 2008). The general validity of this study's criticism should be tested by other measures to compensate for the limitation of the time resolution of the blood-oxygen-level-dependent (BOLD) signal. In this article, we report an EEG study on the domain-generality of visual self-representation. Domain-general self-representation was operationally defined as the self-relevance common to one's own Face and Cup; three levels of familiarity, Self, Familiar, and Unfamiliar, were prepared for each. There was another condition, Visual Field, that manipulated visual hemifield during stimulus presentation, but it was collapsed because it produced no interaction with stimulus familiarity. Our results confirmed comparable phase resetting in both domains in response to familiarity manipulation, which occurred within the medial frontal area during 270-390 ms poststimulus and in the theta band. However, self-specific dissociation was observed only for Face. The results here support the conclusion that visual self-representation is domain-specific and that the oscillatory responses observed suggest evidence of face-specific visual self-representation. Results also revealed an inter-trial phase coherency decrease specifically for Self-Face within the right fusiform area during 170-290 ms poststimulus and in the alpha and theta band, suggesting reduced functional demand for Self-Face represented by sharpened networks.

  9. Music training is associated with cortical synchronization reflected in EEG coherence during verbal memory encoding

    PubMed Central

    Cheung, Mei-chun; Chan, Agnes S.; Liu, Ying; Law, Derry; Wong, Christina W. Y.

    2017-01-01

    Music training can improve cognitive functions. Previous studies have shown that children and adults with music training demonstrate better verbal learning and memory performance than those without such training. Although prior studies have shown an association between music training and changes in the structural and functional organization of the brain, there is no concrete evidence of the underlying neural correlates of the verbal memory encoding phase involved in such enhanced memory performance. Therefore, we carried out an electroencephalography (EEG) study to investigate how music training was associated with brain activity during the verbal memory encoding phase. Sixty participants were recruited, 30 of whom had received music training for at least one year (the MT group) and 30 of whom had never received music training (the NMT group). The participants in the two groups were matched for age, education, gender distribution, and cognitive capability. Their verbal and visual memory functions were assessed using standardized neuropsychological tests and EEG was used to record their brain activity during the verbal memory encoding phase. Consistent with previous studies, the MT group demonstrated better verbal memory than the NMT group during both the learning and the delayed recall trials in the paper-and-pencil tests. The MT group also exhibited greater learning capacity during the learning trials. Compared with the NMT group, the MT group showed an increase in long-range left and right intrahemispheric EEG coherence in the theta frequency band during the verbal memory encoding phase. In addition, their event-related left intrahemispheric theta coherence was positively associated with subsequent verbal memory performance as measured by discrimination scores. These results suggest that music training may modulate the cortical synchronization of the neural networks involved in verbal memory formation. PMID:28358852

  10. Music training is associated with cortical synchronization reflected in EEG coherence during verbal memory encoding.

    PubMed

    Cheung, Mei-Chun; Chan, Agnes S; Liu, Ying; Law, Derry; Wong, Christina W Y

    2017-01-01

    Music training can improve cognitive functions. Previous studies have shown that children and adults with music training demonstrate better verbal learning and memory performance than those without such training. Although prior studies have shown an association between music training and changes in the structural and functional organization of the brain, there is no concrete evidence of the underlying neural correlates of the verbal memory encoding phase involved in such enhanced memory performance. Therefore, we carried out an electroencephalography (EEG) study to investigate how music training was associated with brain activity during the verbal memory encoding phase. Sixty participants were recruited, 30 of whom had received music training for at least one year (the MT group) and 30 of whom had never received music training (the NMT group). The participants in the two groups were matched for age, education, gender distribution, and cognitive capability. Their verbal and visual memory functions were assessed using standardized neuropsychological tests and EEG was used to record their brain activity during the verbal memory encoding phase. Consistent with previous studies, the MT group demonstrated better verbal memory than the NMT group during both the learning and the delayed recall trials in the paper-and-pencil tests. The MT group also exhibited greater learning capacity during the learning trials. Compared with the NMT group, the MT group showed an increase in long-range left and right intrahemispheric EEG coherence in the theta frequency band during the verbal memory encoding phase. In addition, their event-related left intrahemispheric theta coherence was positively associated with subsequent verbal memory performance as measured by discrimination scores. These results suggest that music training may modulate the cortical synchronization of the neural networks involved in verbal memory formation.

  11. Quantitative Changes in the Sleep EEG at Moderate Altitude (1630 m and 2590 m)

    PubMed Central

    Stadelmann, Katrin; Latshang, Tsogyal D.; Lo Cascio, Christian M.; Tesler, Noemi; Stoewhas, Anne-Christin; Kohler, Malcolm; Bloch, Konrad E.; Huber, Reto; Achermann, Peter

    2013-01-01

    Background Previous studies have observed an altitude-dependent increase in central apneas and a shift towards lighter sleep at altitudes >4000 m. Whether altitude-dependent changes in the sleep EEG are also prevalent at moderate altitudes of 1600 m and 2600 m remains largely unknown. Furthermore, the relationship between sleep EEG variables and central apneas and oxygen saturation are of great interest to understand the impact of hypoxia at moderate altitude on sleep. Methods Fourty-four healthy men (mean age 25.0±5.5 years) underwent polysomnographic recordings during a baseline night at 490 m and four consecutive nights at 1630 m and 2590 m (two nights each) in a randomized cross-over design. Results Comparison of sleep EEG power density spectra of frontal (F3A2) and central (C3A2) derivations at altitudes compared to baseline revealed that slow-wave activity (SWA, 0.8–4.6 Hz) in non-REM sleep was reduced in an altitude-dependent manner (∼4% at 1630 m and 15% at 2590 m), while theta activity (4.6–8 Hz) was reduced only at the highest altitude (10% at 2590 m). In addition, spindle peak height and frequency showed a modest increase in the second night at 2590 m. SWA and theta activity were also reduced in REM sleep. Correlations between spectral power and central apnea/hypopnea index (AHI), oxygen desaturation index (ODI), and oxygen saturation revealed that distinct frequency bands were correlated with oxygen saturation (6.4–8 Hz and 13–14.4 Hz) and breathing variables (AHI, ODI; 0.8–4.6 Hz). Conclusions The correlation between SWA and AHI/ODI suggests that respiratory disturbances contribute to the reduction in SWA at altitude. Since SWA is a marker of sleep homeostasis, this might be indicative of an inability to efficiently dissipate sleep pressure. PMID:24167552

  12. Effects of acute nicotine administration on behavioral and neural (EEG) correlates of working memory in non-smokers.

    PubMed

    Fisher, Derek J; Daniels, Richelle; Jaworska, Natalia; Knobelsdorf, Amy; Knott, Verner J

    2012-01-06

    Enhancements in working memory (WM) performance have been previously reported following acute smoking/nicotine. Neuroimaging and behavioral assessments of nicotine's effects on WM have yielded inconsistent findings. Few studies, however, have examined the effects of nicotine on WM-related neural activity in non-smokers. The present study examined the effect of acute nicotine gum administration (6 mg) on electroencephalographic (EEG) activity (alpha(1), alpha(2) and theta bands) and performance on the parametrically manipulated N-back task of WM in 20 non-smoking adults. EEG activity varied with WM load (e.g. alpha(1) decreasing and theta increasing). Performance on the N-back was also load-sensitive, with slower reaction times and decreased accuracy associated with increasing memory load. Neither response speed nor accuracy measures were affected by nicotine but EEG was, with the effects varying by load and brain region. Nicotine-induced increases in alpha(2) and theta were observed under lower (0-, 1-back) memory load conditions Additionally, nicotine significantly reduced signal detection sensitivity values and altered response bias toward being more conservative at all levels of the N-back. Taken together, these findings suggest that while nicotine may boost WM neural processes at lower levels of WM load in non-smokers, it also may activate concurrent behavioral inhibition networks that negate any effects on behavioral performance. Additionally, nicotine appears to have no impact, or perhaps a negative impact, on these processes under more demanding (2-back, 3-back) conditions in non-smokers.

  13. Frontal EEG/ERP correlates of attentional processes, cortisol and motivational states in adolescents from lower and higher socioeconomic status

    PubMed Central

    D'Angiulli, Amedeo; Weinberg, Joanne; Oberlander, Tim F.; Grunau, Ruth E.; Hertzman, Clyde; Maggi, Stefania

    2012-01-01

    Event-related potentials (ERPs) and other electroencephalographic (EEG) evidence show that frontal brain areas of higher and lower socioeconomic status (SES) children are recruited differently during selective attention tasks. We assessed whether multiple variables related to self-regulation (perceived mental effort) emotional states (e.g., anxiety, stress, etc.) and motivational states (e.g., boredom, engagement, etc.) may co-occur or interact with frontal attentional processing probed in two matched-samples of fourteen lower-SES and higher-SES adolescents. ERP and EEG activation were measured during a task probing selective attention to sequences of tones. Pre- and post-task salivary cortisol and self-reported emotional states were also measured. At similar behavioural performance level, the higher-SES group showed a greater ERP differentiation between attended (relevant) and unattended (irrelevant) tones than the lower-SES group. EEG power analysis revealed a cross-over interaction, specifically, lower-SES adolescents showed significantly higher theta power when ignoring rather than attending to tones, whereas, higher-SES adolescents showed the opposite pattern. Significant theta asymmetry differences were also found at midfrontal electrodes indicating left hypo-activity in lower-SES adolescents. The attended vs. unattended difference in right midfrontal theta increased with individual SES rank, and (independently from SES) with lower cortisol task reactivity and higher boredom. Results suggest lower-SES children used additional compensatory resources to monitor/control response inhibition to distracters, perceiving also more mental effort, as compared to higher-SES counterparts. Nevertheless, stress, boredom and other task-related perceived states were unrelated to SES. Ruling out presumed confounds, this study confirms the midfrontal mechanisms responsible for the SES effects on selective attention reported previously and here reflect genuine cognitive

  14. Prestimulus theta in the human hippocampus predicts subsequent recognition but not recall.

    PubMed

    Merkow, Maxwell B; Burke, John F; Stein, Joel M; Kahana, Michael J

    2014-12-01

    Human theta (4-8 Hz) activity in the medial temporal lobe correlates with memory formation; however, the precise role that theta plays in the memory system remains elusive (Hanslmayr and Staudigl, ). Recently, prestimulus theta activity has been associated with successful memory formation, although its specific cognitive role remains unknown (e.g., Fell et al., 2011). In this report, we demonstrate that prestimulus theta in the hippocampus indexes encoding that supports old-new recognition memory but not recall. These findings suggest that human hippocampal prestimulus theta may preferentially participate in the encoding of item information, as opposed to associative information.

  15. Prestimulus theta in the human hippocampus predicts subsequent recognition but not recall

    PubMed Central

    Merkow, Maxwell B.; Burke, John F.; Stein, Joel M.; Kahana, Michael J.

    2014-01-01

    Human theta (4−8 Hz) activity in the medial temporal lobe correlates with memory formation; however, the precise role that theta plays in the memory system remains elusive (Hanslmayr and Staudigl, 2013). Recently, prestimulus theta activity has been associated with successful memory formation, although its specific cognitive role remains unknown (e.g. Fell et al., 2011). In this report, we demonstrate that prestimulus theta in the hippocampus indexes encoding that supports old–new recognition memory but not recall. These findings suggest that human hippocampal prestimulus theta may preferentially participate in the encoding of item information, as opposed to associative information. PMID:25074395

  16. EEG power asymmetry and functional connectivity as a marker of treatment effectiveness in DBS surgery for depression.

    PubMed

    Quraan, Maher A; Protzner, Andrea B; Daskalakis, Zafiris J; Giacobbe, Peter; Tang, Chris W; Kennedy, Sidney H; Lozano, Andres M; McAndrews, Mary P

    2014-04-01

    Recently, deep brain stimulation (DBS) has been evaluated as an experimental therapy for treatment-resistant depression. Although there have been encouraging results in open-label trials, about half of the patients fail to achieve meaningful benefit. Although progress has been made in understanding the neurobiology of MDD, the ability to characterize differences in brain dynamics between those who do and do not benefit from DBS is lacking. In this study, we investigated EEG resting-state data recorded from 12 patients that have undergone DBS surgery. Of those, six patients were classified as responders to DBS, defined as an improvement of 50% or more on the 17-item Hamilton Rating Scale for Depression (HAMD-17). We compared hemispheric frontal theta and parietal alpha power asymmetry and synchronization asymmetry between responders and non-responders. Hemispheric power asymmetry showed statistically significant differences between responders and non-responders with healthy controls showing an asymmetry similar to responders but opposite to non-responders. This asymmetry was characterized by an increase in frontal theta in the right hemisphere relative to the left combined with an increase in parietal alpha in the left hemisphere relative to the right in non-responders compared with responders. Hemispheric mean synchronization asymmetry showed a statistically significant difference between responders and non-responders in the theta band, with healthy controls showing an asymmetry similar to responders but opposite to non-responders. This asymmetry resulted from an increase in frontal synchronization in the right hemisphere relative to the left combined with an increase in parietal synchronization in the left hemisphere relative to the right in non-responders compared with responders. Connectivity diagrams revealed long-range differences in frontal/central-parietal connectivity between the two groups in the theta band. This pattern was observed irrespective of

  17. PyEEG: an open source Python module for EEG/MEG feature extraction.

    PubMed

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

    2011-01-01

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

  18. A model code for the radiative theta pinch

    SciTech Connect

    Lee, S.; Saw, S. H.; Lee, P. C. K.; Akel, M.; Damideh, V.; Khattak, N. A. D.; Mongkolnavin, R.; Paosawatyanyong, B.

    2014-07-15

    A model for the theta pinch is presented with three modelled phases of radial inward shock phase, reflected shock phase, and a final pinch phase. The governing equations for the phases are derived incorporating thermodynamics and radiation and radiation-coupled dynamics in the pinch phase. A code is written incorporating correction for the effects of transit delay of small disturbing speeds and the effects of plasma self-absorption on the radiation. Two model parameters are incorporated into the model, the coupling coefficient f between the primary loop current and the induced plasma current and the mass swept up factor f{sub m}. These values are taken from experiments carried out in the Chulalongkorn theta pinch.

  19. Cold iron cos THETA magnet option for the SSC

    SciTech Connect

    Reardon, P.

    1985-01-01

    We review first the evolution over the past several years of a cold iron, high field cos THETA magnet design option for the SSC. We note the collaborative approach pursued by BNL and LBL on the 2-in-1 option, and the culmination of this effort in the tests of the BNL 4.5 m model magnets. Next, we discuss the subsequent 1-in-1 option being pursued jointly by BNL, Fermilab and LBL.

  20. Correlation of hippocampal theta rhythm with changes in cutaneous temperature

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.; Saleh, M. A.; Karem, R. D.

    1974-01-01

    Investigation of the possibility that the hippocampus performs the function of alerting an animal to changes in cutaneous temperature, using unanesthetized, loosely restrained rabbits. The results indicate that the hippocampal theta rhythm, which appears to be evoked by changes in cutaneous temperature, can be related to a specific type of hyppocampal neuron which is, in turn, connected with other areas of the brain involved in temperature regulation.

  1. The role of REM sleep theta activity in emotional memory

    PubMed Central

    Hutchison, Isabel C.; Rathore, Shailendra

    2015-01-01

    While non-REM (NREM) sleep has been strongly implicated in the reactivation and consolidation of memory traces, the role of rapid-eye movement (REM) sleep remains unclear. A growing body of research on humans and animals provide behavioral evidence for a role of REM sleep in the strengthening and modulation of emotional memories. Theta activity—which describes low frequency oscillations in the local field potential within the hippocampus, amygdala and neocortex—is a prominent feature of both wake and REM sleep in humans and rodents. Theta coherence between the hippocampus and amygdala drives large-scale pontine-geniculo-occipital (PGO) waves, the density of which predicts increases in plasticity-related gene expression. This could potentially facilitate the processing of emotional memory traces within the hippocampus during REM sleep. Further, the timing of hippocampal activity in relation to theta phase is vital in determining subsequent potentiation of neuronal activity. This could allow the emotionally modulated strengthening of novel and gradual weakening of consolidated hippocampal memory traces during REM sleep. Hippocampal theta activity is also correlated with REM sleep levels of achetylcholine - which is thought to reduce hippocampal inputs in the neocortex. The additional low levels of noradrenaline during REM sleep, which facilitate feedback within the neocortex, could allow the integration of novel memory traces previously consolidated during NREM sleep. We therefore propose that REM sleep mediates the prioritized processing of emotional memories within the hippocampus, the integration of previously consolidated memory traces within the neocortex, as well as the disengagement of consolidated neocortical memory traces from the hippocampus. PMID:26483709

  2. Theta Coordinated Error-Driven Learning in the Hippocampus

    PubMed Central

    Ketz, Nicholas; Morkonda, Srinimisha G.; O'Reilly, Randall C.

    2013-01-01

    The learning mechanism in the hippocampus has almost universally been assumed to be Hebbian in nature, where individual neurons in an engram join together with synaptic weight increases to support facilitated recall of memories later. However, it is also widely known that Hebbian learning mechanisms impose significant capacity constraints, and are generally less computationally powerful than learning mechanisms that take advantage of error signals. We show that the differential phase relationships of hippocampal subfields within the overall theta rhythm enable a powerful form of error-driven learning, which results in significantly greater capacity, as shown in computer simulations. In one phase of the theta cycle, the bidirectional connectivity between CA1 and entorhinal cortex can be trained in an error-driven fashion to learn to effectively encode the cortical inputs in a compact and sparse form over CA1. In a subsequent portion of the theta cycle, the system attempts to recall an existing memory, via the pathway from entorhinal cortex to CA3 and CA1. Finally the full theta cycle completes when a strong target encoding representation of the current input is imposed onto the CA1 via direct projections from entorhinal cortex. The difference between this target encoding and the attempted recall of the same representation on CA1 constitutes an error signal that can drive the learning of CA3 to CA1 synapses. This CA3 to CA1 pathway is critical for enabling full reinstatement of recalled hippocampal memories out in cortex. Taken together, these new learning dynamics enable a much more robust, high-capacity model of hippocampal learning than was available previously under the classical Hebbian model. PMID:23762019

  3. The role of REM sleep theta activity in emotional memory.

    PubMed

    Hutchison, Isabel C; Rathore, Shailendra

    2015-01-01

    While non-REM (NREM) sleep has been strongly implicated in the reactivation and consolidation of memory traces, the role of rapid-eye movement (REM) sleep remains unclear. A growing body of research on humans and animals provide behavioral evidence for a role of REM sleep in the strengthening and modulation of emotional memories. Theta activity-which describes low frequency oscillations in the local field potential within the hippocampus, amygdala and neocortex-is a prominent feature of both wake and REM sleep in humans and rodents. Theta coherence between the hippocampus and amygdala drives large-scale pontine-geniculo-occipital (PGO) waves, the density of which predicts increases in plasticity-related gene expression. This could potentially facilitate the processing of emotional memory traces within the hippocampus during REM sleep. Further, the timing of hippocampal activity in relation to theta phase is vital in determining subsequent potentiation of neuronal activity. This could allow the emotionally modulated strengthening of novel and gradual weakening of consolidated hippocampal memory traces during REM sleep. Hippocampal theta activity is also correlated with REM sleep levels of achetylcholine - which is thought to reduce hippocampal inputs in the neocortex. The additional low levels of noradrenaline during REM sleep, which facilitate feedback within the neocortex, could allow the integration of novel memory traces previously consolidated during NREM sleep. We therefore propose that REM sleep mediates the prioritized processing of emotional memories within the hippocampus, the integration of previously consolidated memory traces within the neocortex, as well as the disengagement of consolidated neocortical memory traces from the hippocampus.

  4. Laminar profile of spontaneous and evoked theta: Rhythmic modulation of cortical processing during word integration.

    PubMed

    Halgren, Eric; Kaestner, Erik; Marinkovic, Ksenija; Cash, Sydney S; Wang, Chunmao; Schomer, Donald L; Madsen, Joseph R; Ulbert, Istvan

    2015-09-01

    Theta may play a central role during language understanding and other extended cognitive processing, providing an envelope for widespread integration of participating cortical areas. We used linear microelectrode arrays in epileptics to define the circuits generating theta in inferotemporal, perirhinal, entorhinal, prefrontal and anterior cingulate cortices. In all locations, theta was generated by excitatory current sinks in middle layers which receive predominantly feedforward inputs, alternating with sinks in superficial layers which receive mainly feedback/associative inputs. Baseline and event-related theta were generated by indistinguishable laminar profiles of transmembrane currents and unit-firing. Word presentation could reset theta phase, permitting theta to contribute to late event-related potentials, even when theta power decreases relative to baseline. Limited recordings during sentence reading are consistent with rhythmic theta activity entrained by a given word modulating the neural background for the following word. These findings show that theta occurs spontaneously, and can be momentarily suppressed, reset and synchronized by words. Theta represents an alternation between feedforward/divergent and associative/convergent processing modes that may temporally organize sustained processing and optimize the timing of memory formation. We suggest that words are initially encoded via a ventral feedforward stream which is lexicosemantic in the anteroventral temporal lobe; its arrival may trigger a widespread theta rhythm which integrates the word within a larger context.

  5. A Modified Theta Projection Model for Creep Behavior of Metals and Alloys

    NASA Astrophysics Data System (ADS)

    Kumar, Manish; Singh, I. V.; Mishra, B. K.; Ahmad, S.; Venugopal Rao, A.; Kumar, Vikas

    2016-09-01

    In this work, a modified theta projection model is proposed for the constitutive modeling of creep behavior of metals and alloys. In the conventional theta projection model, strain hardening exponent is a function of time and theta, whereas in the modified theta projection model, the exponent is taken as a function of time, theta, and applied stress. The results obtained by the modified theta projection model for Al 2124 T851 alloy at constant uniaxial tensile stress are compared with the experimental results and with the predictions of the conventional theta projection method. The creep behavior of Al 7075 T651 alloy is also predicted using modified and conventional theta projection model and compared with the available experimental data. It is observed that the modified theta projection model captures the creep behavior more accurately as compared to the conventional theta projection model. The modified theta projection model can be used to predict the creep strain of pure metals and class M alloys (similar creep behavior to pure metals) for intermediate range of stress and temperature.

  6. Which EEG patterns in coma are nonconvulsive status epilepticus?

    PubMed

    Trinka, Eugen; Leitinger, Markus

    2015-08-01

    Nonconvulsive status epilepticus (NCSE) is common in patients with coma with a prevalence between 5% and 48%. Patients in deep coma may exhibit epileptiform EEG patterns, such as generalized periodic spikes, and there is an ongoing debate about the relationship of these patterns and NCSE. The purposes of this review are (i) to discuss the various EEG patterns found in coma, its fluctuations, and transitions and (ii) to propose modified criteria for NCSE in coma. Classical coma patterns such as diffuse polymorphic delta activity, spindle coma, alpha/theta coma, low output voltage, or burst suppression do not reflect NCSE. Any ictal patterns with a typical spatiotemporal evolution or epileptiform discharges faster than 2.5 Hz in a comatose patient reflect nonconvulsive seizures or NCSE and should be treated. Generalized periodic diacharges or lateralized periodic discharges (GPDs/LPDs) with a frequency of less than 2.5 Hz or rhythmic discharges (RDs) faster than 0.5 Hz are the borderland of NCSE in coma. In these cases, at least one of the additional criteria is needed to diagnose NCSE (a) subtle clinical ictal phenomena, (b) typical spatiotemporal evolution, or (c) response to antiepileptic drug treatment. There is currently no consensus about how long these patterns must be present to qualify for NCSE, and the distinction from nonconvulsive seizures in patients with critical illness or in comatose patients seems arbitrary. The Salzburg Consensus Criteria for NCSE [1] have been modified according to the Standardized Terminology of the American Clinical Neurophysiology Society [2] and validated in three different cohorts, with a sensitivity of 97.2%, a specificity of 95.9%, and a diagnostic accuracy of 96.3% in patients with clinical signs of NCSE. Their diagnostic utility in different cohorts with patients in deep coma has to be studied in the future. This article is part of a Special Issue entitled "Status Epilepticus".

  7. Impaired theta-gamma coupling in APP-deficient mice

    PubMed Central

    Zhang, Xiaomin; Zhong, Wewei; Brankačk, Jurij; Weyer, Sascha W.; Müller, Ulrike C.; Tort, Adriano B. L.; Draguhn, Andreas

    2016-01-01

    Amyloid precursor protein (APP) is critically involved in the pathophysiology of Alzheimer’s disease, but its physiological functions remain elusive. Importantly, APP knockout (APP-KO) mice exhibit cognitive deficits, suggesting that APP plays a role at the neuronal network level. To investigate this possibility, we recorded local field potentials (LFPs) from the posterior parietal cortex, dorsal hippocampus and lateral prefrontal cortex of freely moving APP-KO mice. Spectral analyses showed that network oscillations within the theta- and gamma-frequency bands were not different between APP-KO and wild-type mice. Surprisingly, however, while gamma amplitude coupled to theta phase in all recorded regions of wild-type animals, in APP-KO mice theta-gamma coupling was strongly diminished in recordings from the parietal cortex and hippocampus, but not in LFPs recorded from the prefrontal cortex. Thus, lack of APP reduces oscillatory coupling in LFP recordings from specific brain regions, despite not affecting the amplitude of the oscillations. Together, our findings reveal reduced cross-frequency coupling as a functional marker of APP deficiency at the network level. PMID:26905287

  8. Effects of neural synchrony on surface EEG.

    PubMed

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

    2014-04-01

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

  9. Eliminating stroop effects with post-hypnotic instructions: Brain mechanisms inferred from EEG.

    PubMed

    Zahedi, Anoushiravan; Stuermer, Birgit; Hatami, Javad; Rostami, Reza; Sommer, Werner

    2017-02-01

    The classic Stroop task demonstrates the persistent and automatic effects of the meaning of color words that are very hard to inhibit when the task is to name the word color. Post-hypnotic instructions may enable highly-hypnotizable participants to inhibit the automatic access to word meaning. Here we compared the consequences of hypnosis alone and hypnosis with post-hypnotic instructions on the Stroop effect and its facilitation and inhibition components. Importantly, we studied the mechanisms of the hypnosis effects at the neural level by analyzing EEG frequencies. Highly hypnotizable participants performed the Stroop task in a counterbalanced design following (1) post-hypnotic suggestions that words had lost their meaning, (2) after hypnosis alone, and (3) in a control condition without hypnosis. The overall Stroop effect and both its facilitation and interference components, were not significant after the post-hypnotic suggestion but in both other conditions. Hypnosis alone neither affected the Stroop effect nor - in contrast to some previous reports and claims - overall performance. EEG recorded during the Stroop task showed a significant increase in both frontal theta and frontal beta power when participants were under the impact of post-hypnotic suggestions, in comparison to the two other sessions. Together, these findings indicate that post-hypnotic suggestions - but not hypnosis alone - are powerful tools for eliciting top down processes. Our EEG findings could be interpreted as clue that this is due to the investment of additional cognitive control.

  10. Effect of spatial ability and sex on EEG power in high school students.

    PubMed

    Arce, C; Ramos, J; Guevara, M A; Corsi-Cabrera, M

    1995-06-01

    Performance at eight cognitive tests and EEG spectral power at rest was computed in 2 groups of men and women, between 17 and 21 years of age, with extreme degrees of spatial ability (SA) evaluated by the spatial relations subtest of the DAT: a low spatial ability group (10 men, 10 women) with scores below percentile 30 and a high spatial ability group (10 men, 10 women) with scores above percentile 80. Ten EEG artifact free samples, 4.096 sec each, were analyzed and absolute (AP) and relative power (RP) were obtained for 5 frequency bands using an FFT. EEG was submitted to principal component analysis and two way ANOVAs. High SA showed lower AP in the entire spectrum with eyes open and closed, and lower alpha 1 RP with eyes open than low SA group regardless of sex. The difference between low and high SA was better explained by high alpha AP at all derivations and high theta AP at right derivations and at left central and occipital regions. Women showed higher beta 1 and beta 2 AP at all derivations except at temporal regions than men regardless of SA scores.

  11. Correlated Components of Ongoing EEG Point to Emotionally Laden Attention – A Possible Marker of Engagement?

    PubMed Central

    Dmochowski, Jacek P.; Sajda, Paul; Dias, Joao; Parra, Lucas C.

    2012-01-01

    Recent evidence from functional magnetic resonance imaging suggests that cortical hemodynamic responses coincide in different subjects experiencing a common naturalistic stimulus. Here we utilize neural responses in the electroencephalogram (EEG) evoked by multiple presentations of short film clips to index brain states marked by high levels of correlation within and across subjects. We formulate a novel signal decomposition method which extracts maximally correlated signal components from multiple EEG records. The resulting components capture correlations down to a one-second time resolution, thus revealing that peak correlations of neural activity across viewings can occur in remarkable correspondence with arousing moments of the film. Moreover, a significant reduction in neural correlation occurs upon a second viewing of the film or when the narrative is disrupted by presenting its scenes scrambled in time. We also probe oscillatory brain activity during periods of heightened correlation, and observe during such times a significant increase in the theta band for a frontal component and reductions in the alpha and beta frequency bands for parietal and occipital components. Low-resolution EEG tomography of these components suggests that the correlated neural activity is consistent with sources in the cingulate and orbitofrontal cortices. Put together, these results suggest that the observed synchrony reflects attention- and emotion-modulated cortical processing which may be decoded with high temporal resolution by extracting maximally correlated components of neural activity. PMID:22623915

  12. EEG to Primary Rewards: Predictive Utility and Malleability by Brain Stimulation

    PubMed Central

    Prause, Nicole; Siegle, Greg J.; Deblieck, Choi; Wu, Allan; Iacoboni, Marco

    2016-01-01

    Theta burst stimulation (TBS) is thought to affect reward processing mechanisms, which may increase and decrease reward sensitivity. To test the ability of TBS to modulate response to strong primary rewards, participants hypersensitive to primary rewards were recruited. Twenty men and women with at least two opposite-sex, sexual partners in the last year received two forms of TBS. Stimulations were randomized to avoid order effects and separated by 2 hours to reduce carryover. The two TBS forms have been demonstrated to inhibit (continuous) or excite (intermittent) the left dorsolateral prefrontal cortex using different pulse patterns, which links to brain areas associated with reward conditioning. After each TBS, participants completed tasks assessing their reward responsiveness to monetary and sexual rewards. Electroencephalography (EEG) was recorded. They also reported their number of orgasms in the weekend following stimulation. This signal was malleable by TBS, where excitatory TBS resulted in lower EEG alpha relative to inhibitory TBS to primary rewards. EEG responses to sexual rewards in the lab (following both forms of TBS) predicted the number of orgasms experienced over the forthcoming weekend. TBS may be useful in modifying hypersensitivity or hyposensitivity to primary rewards that predict sexual behaviors. Since TBS altered the anticipation of a sexual reward, TBS may offer a novel treatment for sexual desire problems. PMID:27902711